WO2019200589A1

WO2019200589A1 - Slot format and signaling in non-orthogonal multiple access wireless communications

Info

Publication number: WO2019200589A1
Application number: PCT/CN2018/083770
Authority: WO
Inventors: Jing LEI; Seyong PARK; Naga Bhushan; Joseph Binamira Soriaga; Tingfang Ji; Yiqing Cao
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2018-04-19
Filing date: 2018-04-19
Publication date: 2019-10-24
Anticipated expiration: 2020-10-19

Abstract

Methods, systems, and devices for wireless communications are described that provide for configuration of multiple different non orthogonal multiple access (NOMA) slot formats for NOMA uplink transmissions. In some cases, the NOMA slot formats may provide one or more uplink symbols configured for reference signal transmissions, control information transmissions, or combinations thereof. A base station may configure a user equipment (UE) for NOMA transmissions according to one of the configured slot formats. In some cases, a base station may signal a NOMA slot format indicator (SFI) to a number of UEs to indicate the NOMA slot format to be used at each UE.

Description

SLOT FORMAT AND SIGNALING IN NON-ORTHOGONAL MULTIPLE ACCESS WIRELESS COMMUNICATIONS

BACKGROUND

The following relates generally to wireless communications, and more specifically to slot format and signaling in non-orthogonal multiple access wireless communications.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform-spread-OFDM (DFT-S-OFDM) . A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

Some wireless communications systems may support multiple access techniques for multiple users by sharing available system resources (e.g., time, frequency, and power) . In some cases, non-orthogonal multiple access (NOMA) techniques may outperform orthogonal multiple access (OMA) techniques, and may allow multiple different transmitters to transmit concurrent transmissions over common time, frequency, and spatial resources. Efficient and reliable techniques for implementing NOMA in a wireless communications system may thus be desirable in order to enhance system access and resource utilization.

SUMMARY

The described techniques relate to improved methods, systems, devices, or apparatuses that support various non-orthogonal multiple access (NOMA) wireless communications slot formats and signaling. Various described techniques provide for configuration of multiple different NOMA slot formats for NOMA uplink transmissions. In some cases, the NOMA slot formats may provide one or more uplink symbols configured for reference signal transmissions, control information transmissions, or combinations thereof. A base station may configure a user equipment (UE) for NOMA transmissions according to one of the configured slot formats. In some cases, a base station may signal a NOMA slot format indicator (SFI) to a number of UEs to indicate the NOMA slot format to be used at each UE.

In some cases, the NOMA slot format may include one or more symbols configured for demodulation reference signal (DMRS) transmissions. In such cases, DMRS symbols for some UEs may be configured toward a beginning of a NOMA slot, and DMRS symbols for other UEs may be configured toward an end of a NOMA slot. In some cases, available DMRS sequences for DMRS symbols at the beginning of the NOMA slot may be orthogonal, which may simplify initial multi user decoding (MUD) , and available DMRS sequences for DMRS symbols later in the NOMA slot may be non-orthogonal, which may increase the size of the resource pool.

In some cases, UEs may transmit uplink control channel (e.g., physical uplink control channel (PUCCH) ) information that may assist a base station in receiving uplink transmissions from the UE. In some cases, a base station may transmit downlink control information (DCI) for use in transmission of one or more NOMA uplink transmissions at a UE.In some cases, the slot configuration may also indicate slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots.

A method of wireless communication at a UE is described. The method may include receiving, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, formatting one or more NOMA uplink transmissions based on the NOMA SFI, and transmitting the one or more NOMA uplink transmissions to the base station.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, format one or more NOMA uplink transmissions based on the NOMA SFI, and transmit the one or more NOMA uplink transmissions to the base station.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, formatting one or more NOMA uplink transmissions based on the NOMA SFI, and transmitting the one or more NOMA uplink transmissions to the base station.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, format one or more NOMA uplink transmissions based on the NOMA SFI, and transmit the one or more NOMA uplink transmissions to the base station.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the one or more NOMA uplink transmissions may be autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the formatting the one or more NOMA uplink transmissions further may include operations, features, means, or instructions for identifying the one or more DMRS symbols within the one or more slots based on the NOMA SFI and selecting a DMRS sequence for the one or more DMRS transmissions based on a location of the one or more DMRS symbols within the one or more slots. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a first set of orthogonal DMRS sequences may be configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences may be configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the formatting the one or more NOMA uplink transmissions further may include operations, features, means, or instructions for identifying a spectral efficiency of the uplink transmissions to the base station and selecting a first number of DMRS symbols when a value of the spectral efficiency may be below a threshold value and a second number of DMRS symbols when the value of the spectral efficiency meets or exceeds the threshold value, where the second number of DMRS symbols may be greater than the first number of DMRS symbols.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the formatting the one or more NOMA uplink transmissions may include operations, features, means, or instructions for identifying an uplink control channel symbol within the one or more slots based on the NOMA SFI, determining that an uplink control channel transmission may be to be transmitted to the base station, the uplink control channel transmission indicating one or more parameters associated with one or more uplink data NOMA transmissions within the one or more slots and formatting the uplink control channel transmission within the uplink control channel symbol. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the uplink control channel transmission includes a predetermined sequence that indicates values for the one or more parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the predetermined sequence may be selected from a set of available sequences based on the values for the one or more parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the predetermined sequence may be transmitted in an absence of a CRC or channel coding.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the uplink control channel transmission includes a set of encoded bits that indicate values for the one or more parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the set of encoded bits may be transmitted with a CRC and channel coding. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the one or more parameters indicate, for the one or more uplink data NOMA transmissions, one or more of a spreading factor, a number of RMSI layers, a modulation order, or any combinations thereof. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the one or more parameters provide enhanced successive interference cancellation (SIC) for the base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the base station, DCI that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes one or more index values of a configuration table that maps a set of configuration parameters to the one or more index values. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the NOMA SFI further indicates slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the slot aggregation information indicates a spreading factor may be to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for differenting slots of the two or more aggregated slots may have different NOMA slot formats.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the receiving further may include operations, features, means, or instructions for receiving the NOMA SFI via a semi-static downlink assignment from the base station. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the receiving further may include operations, features, means, or instructions for receiving the NOMA SFI via RRC signaling. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the receiving further may include operations, features, means, or instructions for receiving the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the receiving further may include operations, features, means, or instructions for receiving a first portion of the NOMA SFI via a semi-static downlink assignment from the base station and receiving a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station.

A method of wireless communication is described. The method may include configuring, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, transmitting, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE, monitoring uplink transmissions in the one or more slots, and decoding two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration.

An apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE, monitor uplink transmissions in the one or more slots, and decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration.

Another apparatus for wireless communication is described. The apparatus may include means for configuring, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, transmitting, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE, monitoring uplink transmissions in the one or more slots, and decoding two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE, monitor uplink transmissions in the one or more slots, and decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the NOMA slot configuration includes one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the set of UEs.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuring further may include operations, features, means, or instructions for configuring a DMRS sequence for the one or more DMRS transmissions based on a location of the one or more DMRS symbols within the one or more slots. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a first set of orthogonal DMRS sequences may be configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences may be configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuring further may include operations, features, means, or instructions for configuring an uplink control channel symbol within the one or more slots. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, an uplink control channel transmission received via the uplink control channel symbol includes a predetermined sequence that indicates values for one or more parameters of an associated uplink NOMA transmission. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the predetermined sequence may be selected from a set of available sequences based on the values for the one or more parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the one or more parameters indicate, for one or more uplink data NOMA transmissions, one or more of a spreading factor, number of transmission layers, a modulation order, or any combinations thereof. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the one or more parameters provide enhanced successive interference cancellation (SIC) for the base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to a first UE of the set of UEs, DCI that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes one or more index values of a configuration table that maps a set of configuration parameters to the one or more index values. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuring further may include operations, features, means, or instructions for configuring a slot aggregation for aggregation of the one or more NOMA uplink transmissions across two or more slots, and where the NOMA SFI includes slot aggregation information. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the slot aggregation information indicates a spreading factor may be to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitting the NOMA SFI further may include operations, features, means, or instructions for transmitting, from the base station, the NOMA SFI via a semi-static downlink assignment. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitting the NOMA SFI further may include operations, features, means, or instructions for transmitting the NOMA SFI via RRC signaling. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitting the NOMA SFI further may include operations, features, means, or instructions for transmitting the NOMA SFI via dynamic signaling in a group common downlink control channel transmission. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitting the NOMA SFI further may include operations, features, means, or instructions for transmitting a first portion of the NOMA SFI via a semi-static downlink assignment and transmitting a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a multi-layer resource spread multiple access (RSMA) transmit chain that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIGs. 4A, 4B, and 4C illustrate examples of NOMA slot formats that include configured demodulation reference signal (DMRS) symbols that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIGs. 5A, 5B, and 5C illustrate examples of NOMA slot formats that include configured uplink control channel symbols that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of a NOMA slot formats that include a downlink control information transmission that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 7 illustrates an example of a NOMA slot formats for slot aggregation that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIGs. 8A and 8B illustrate examples of NOMA slot formats for slot aggregation that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 9 illustrates an example of a process flow that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIGs. 10 and 11 show block diagrams of devices that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 12 shows a block diagram of a device that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 13 shows a diagram of a system including a device that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIGs. 14 and 15 show block diagrams of devices that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 16 shows a block diagram of a device that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIG. 17 shows a diagram of a system including a device that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

FIGs. 18 through 25 show flowcharts illustrating methods that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Some wireless communications systems may support non-orthogonal multiple access (NOMA) techniques, enabling transmitters to transmit concurrently over common transmission resources. NOMA techniques may help to enhance the achievable spectral efficiency (SE) of the wireless communications system. In some aspects of the present disclosure, a wireless communications system may implement NOMA techniques for uplink transmissions from a user equipment (UE) to a serving base station that may allow the base station to successfully decode the UE transmission, such as through successive interference cancellation (SIC) at a multi user decoder (MUD) . Various described techniques provide for configuration of multiple different NOMA slot formats for NOMA uplink transmissions. In some cases, the NOMA slot formats may provide one or more uplink symbols configured for reference signal transmissions, control information transmissions, or combinations thereof. A base station may configure UEs for NOMA transmissions according to one of the configured NOMA slot formats. In some cases, a base station may signal a NOMA slot format indicator (SFI) to a number of UEs to indicate the NOMA slot format to be used at each UE.

In some cases, the NOMA slot format may include one or more symbols configured for demodulation reference signal (DMRS) transmissions. DMRS symbols for some UEs may be configured toward a beginning of a NOMA slot, and DMRS symbols for other UEs may be configured toward an end of a NOMA slot. Uplink transmissions of UEs with DMRS symbols earlier in the slot may be decoded, and used for interference cancellation (e.g., via successive interference cancellation (SIC) techniques) for UEs with DMRS symbols later in the slot. In some cases, available DMRS sequences for DMRS symbols at the beginning of the NOMA slot may be orthogonal, which may simplify initial multi user decoding (MUD) , and available DMRS sequences for DMRS symbols later in the NOMA slot may be non-orthogonal, which may increase the size of the resource pool.

In some cases, UEs may transmit uplink control channel (e.g., physical uplink control channel (PUCCH) ) information that may assist a base station in receiving uplink transmissions from the UE. In some cases, the uplink control channel information may be indicated through a control channel sequence that may be selected based on one or more parameters associated the NOMA uplink transmissions, such as a spreading factor, number of layers of multi-layer resource spread multiple access (ML-RSMA) transmissions, a modulation order, or any combinations thereof. In some cases, such uplink control channel information may be indicated through a small number of encoded bits that may provide an index into a configuration table.

In some cases, a base station may transmit downlink control information (DCI) for use in transmission of one or more NOMA uplink transmissions at a UE. In some cases, the DCI may be a compact NOMA DCI that may indicate one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. In some cases, the compact NOMA DCI may include one or more index values of a configuration table that maps a plurality of configuration parameters to the one or more index values. In some cases, the slot configuration may also indicate slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots. The slot aggregation information may indicate, in some cases, a spreading factor is to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.

Aspects of the disclosure are initially described in the context of a wireless communications system. Examples of various slot formats and related signaling are then discussed. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to slot format and signaling in non-orthogonal multiple access wireless communications.

FIG. 1 illustrates an example of a wireless communications system 100 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices. In some cases, UEs 115 and base stations 105 may use NOMA transmission techniques in which multiple UEs 115 may transmit concurrent uplink transmissions using common resources.

Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas. Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation Node B or giga-nodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) . The UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.

The geographic coverage area 110 for a base station 105 may be divided into sectors making up only a portion of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

The term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE 115 may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.

In some cases, a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) . One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105. In some cases, groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some cases, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs 115 without the involvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with one another. For example, base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1 or other interface) . Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2 or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) . The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) . Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) . In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .

Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 MHz to 300 GHz. Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that can tolerate interference from other users.

Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

In some cases, wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a CA configuration in conjunction with CCs operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.

In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving devices are equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

In some cases, wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may in some cases perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data. At the Physical (PHY) layer, transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) . In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of T _s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms) , where the frame period may be expressed as T _f = 307,200 T _s. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) . In other cases, a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125. For example, a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an E-UTRA absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115. Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) . In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as OFDM or DFT-s-OFDM) .

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR, etc. ) . For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc. ) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) . In some examples, each served UE 115 may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.

In some cases, one or more base stations 105 may configure one or more UEs for NOMA communications. In some cases, a base station 105 may configure multiple different NOMA slot formats for NOMA uplink transmissions. Such NOMA slot formats may provide one or more uplink symbols configured for reference signal transmissions, control information transmissions, or combinations thereof. The base station 105 may configure a UE 115 for NOMA transmissions according to one of the configured slot formats. In some cases, the base station 105 may signal a NOMA slot format indicator (SFI) to a number of UEs 115 to indicate the NOMA slot format to be used at each UE 115.

In some cases, the NOMA slot format may include one or more symbols configured for DMRS transmissions. In such cases, DMRS symbols for some UEs 115 may be configured toward a beginning of a NOMA slot, and DMRS symbols for other UEs 115 may be configured toward an end of a NOMA slot. In some cases, available DMRS sequences for DMRS symbols at the beginning of the NOMA slot may be orthogonal, which may simplify initial multi user decoding (MUD) , and available DMRS sequences for DMRS symbols later in the NOMA slot may be non-orthogonal, which may increase the size of the resource pool.

In some cases, UEs 115 may transmit uplink control channel (e.g., PUCCH) information that may assist a base station 105 in receiving uplink transmissions from the UE 115. In some cases, a base station 105 may transmit DCI for use in transmission of one or more NOMA uplink transmissions at a UE 115. In some cases, the slot configuration may also indicate slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots.

FIG. 2 illustrates an example of a wireless communications system 200 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. In some examples, wireless communications system 200 may implement aspects of wireless communications system 100. In the example of FIG. 2, the wireless communications system 200 may include base station 105-a, which may be an example of a base station 105 of FIG. 1. The wireless communications system 200 may also include first UE 115-a and second UE 115-b, which may each be examples of a UE 115 of FIG. 1, that are located within coverage area 110-a of base station 105-a.

The UEs 115 may be configured for NOMA transmissions, such as according to multi-layer RSMA transmission techniques. For example, UEs 115 may receive NOMA configuration, including a NOMA SFI 205, via downlink carriers 210 and may transmit concurrent uplink transmissions using common NOMA uplink resources 215 via uplink carriers 220. In some cases, uplink NOMA transmissions may allow the UEs 115 to autonomously transmit uplink transmissions in the absence of a specific grant of uplink resources to the UE 115. Such grant-free uplink transmissions may significantly reduce downlink overhead of the wireless communications system 200. For example, grant-based uplink transmissions may consume one downlink grant, which indicates uplink resources for the uplink transmission. In many deployments, a majority of uplink transmission (e.g., greater than 90 %in some deployments) transmit a relatively small amount of data (e.g., 40 bytes or less) , and thus the downlink grants consume a relatively large amount of network resources relative to the uplink data transmissions. Further, as the number of UEs 115 in a system increase (e.g., in some IoT deployments numerous UEs 115 may be present in a coverage area of base station 105-a) and relatively small amounts of data are transmitted in uplink transmissions, the overhead of downlink control information (DCI) that provides grants for the uplink traffic may also increase. Thus, NOMA techniques may allow concurrent transmissions from UEs 115, and may allow the UEs 115 to transmit via NOMA uplink resources 215 in the absence of an uplink grant, and may thus increase network efficiency.

In some cases, the NOMA SFI may indicate a NOMA slot format to be used for uplink transmissions using NOMA uplink resources 215. In some cases, as will be discussed in more detail below, the NOMA slot format may include one or more symbols configured for DMRS transmissions, which may include additional DMRS symbols than may otherwise be configured for OMA transmissions. The NOMA slot format indicated in the NOMA SFI may be selected from a number of available slot formats, examples of which may include: front-loaded uplink DMRS + PUSCH + optional PDCCH/PUSCH; short PUCCH + DMRS + PUSCH + optional PDCCH/PDSCH; front-loaded uplink DMRS + PUSCH + additional DMRS + optional PDCCH/PDSCH; PDCCH + uplink DMRS + optional short PUCCH + PUSCH; PDCCH + front-loaded uplink DMRS + PUSCH; PDCCH + short PUCCH + DMRS + PUSCH; PDCCH + front-loaded uplink DMRS + PUSCH + additional DMRS; PDCCH + DMRS + short PUCCH + PUSCH. It is to be understood that this non-exhaustive list of examples is provided for illustration and discussion purposes only, and that other slot formats can be readily identified as being within the scope of the present disclosure.

In some cases, the slot format may include DMRS symbols that for some certain UE 115, such as the first UE 115-a, may be configured toward a beginning of a NOMA slot, and DMRS symbols for other UEs 115, such as second UE 115-b, may be configured toward an end of a NOMA slot. In such cases, the base station 105-a may decode the concurrent uplink transmissions and, based on the earlier DMRS symbol location of the first UE 115-a received via first uplink carrier 220-a, and decode a first uplink transmission of the first UE 115-a. Parameters associated with the decoded first uplink transmission may then be used in successive interference cancellation (SIC) techniques, in conjunction with the later DMRS of the second UE 115-b, to decode a second uplink transmission of the second UE 115-b that is transmitted via second uplink carrier 220-b. In some cases, available DMRS sequences for DMRS symbols at the beginning of the NOMA slot may be orthogonal, which may simplify initial multi user decoding (MUD) , and available DMRS sequences for DMRS symbols later in the NOMA slot may be non-orthogonal, which may increase the size of the resource pool. In some cases, the NOMA SFI 205 may also indicate slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots. The slot aggregation information may indicate, in some cases, a spreading factor is to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.

In some cases, UEs 115 may transmit uplink control channel (e.g., PUCCH) information that may assist the base station 105-a in receiving uplink transmissions from the UEs 115. As will be discussed in more detail below, the uplink control channel information may be indicated through a control channel sequence that may be selected based on one or more parameters associated the NOMA uplink transmissions, such as a spreading factor, number of layers of ML-RSMA transmissions, a modulation order, or any combinations thereof. In some cases, such uplink control channel information may be indicated through a small number of encoded bits that may provide an index into a configuration table.

Additionally or alternatively, the base station 105-a may transmit downlink control information (DCI) for use in transmission of one or more NOMA uplink transmissions by the UE 115. In some cases, the DCI may be a compact NOMA DCI that may indicate one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. In some cases, the NOMA DCI may be transmitted responsive to a received uplink NOMA transmission, or in advance of an uplink NOMA transmission. In some cases, the compact NOMA DCI may include one or more index values of a configuration table that maps a plurality of configuration parameters to the one or more index values.

The NOMA SFI 205 may, in some cases, be indicated to the UEs 115 in a semi-static manner. For example, the base station 105-a may transmit radio resource control (RRC) signaling as part on a connection establishment, and following establishment of the connection, that may indicate the NOMA SFI. In some cases, the configured slot format may be cell specific, and may depend upon operation modes, use cases, and deployment. In other cases, the NOMA SFI 205 may be dynamically indicated to the UEs 115, such as via broadcast communications to the UEs 115. In some cases, the base station 105-a may dynamically indicate the NOMA SFI via a dynamic assignment carried by a group common physical downlink control channel (PDCCH) transmission. In further cases, portions of the NOMA slot format may be semi-static (e.g., uplink control channel symbol locations) and configured via RRC signaling, and other portions of the NOMA slot format may be dynamic (e.g., DMRS symbol locations) and configured dynamically by other control channel signaling (e.g., group common PDCCH) .

As indicated above, NOMA transmissions may use ML-RSMA transmission techniques. FIG. 3 illustrates an example of a multi-layer resource spread multiple access transmit chain 300 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The ML-RSMA transmit chain 300 may be implemented in a UE (e.g., a UE 115 of FIG. 1 or 2) , although the concepts provided herein may be applied to any ML-RSMA transmitter.

The ML-RSMA transmit chain 300 may include a channel encoder 310, a rate matching/bit interleaving component 315, a modulator 320, a de-multiplexing (e.g., demux) component 325, m spreading sequence components 335, m gain components 340, a scrambling component 345, a tone interleaving component 350, a tone mapper 355, and a waveform component 360. Each of these components may use ML-RSMA parameters, such as an encoding scheme, rate matching, modulation (e.g., MCS) , spreading factor, gain, and the like, to perform an action. For example, the modulator 320 may apply an MCS based on an MCS indicated by a base station, or the demux component 325 may split a bit stream into m layers, where the UE selects the number of layers (i.e., m) . As shown, the ML-RSMA transmit chain 300 uses the same parameters for each layer for the channel encoder 310, the rate matching/bit interleaving component 315, the modulator 320, the scrambling component 345, the tone interleaving component 350, the tone mapper 355, and the waveform component 360, although in other implementations different parameters may be used in such components.

As an example, a UE may identify uplink data 305 to be transmitted. The UE may provide the data to a channel encoder 310. The channel encoder 310 may apply a coding technique to the transport blocks such as, for example, a low-density parity-check (LDPC) encoding algorithm, to generate coded data bits. A rate matching/bit interleaving component 315 may perform rate matching on the coded data bits. For example, rate matching may involve selecting which of the coded data bits to transmit, and which of the coded data bits to discard. Bit interleaving may include, for example, forward error correction (FEC) . The channel coded data may be provided to a modulator 320 that may modulate the coded data according to a modulation and coding scheme (MCS) to generate a data symbol vector that is a sequence of modulated symbols.

The UE may then provide the modulated symbols to a demux component 325, which splits the modulated symbols into multiple segments of modulated symbols. The UE may assign the segments to layers 330 in the ML-RSMA configuration. For example, the UE may use m layers and split the modulated symbol into m segments. The demux component 325 may be a different points in the transmit chain. In some cases, multiple layers with a common parameter for a component (e.g., sharing a common MCS) may be represented by a single component (e.g., a single encoder and a single modulator) . Thus, if multiple layers use a common parameter related to a component, the multiple layers may be shown to be handled by a single component.

A spreading sequence component 335 of a layer may apply a spreading sequence unique to that layer. For example, spreading sequence component 335-a may apply a first spreading sequence to a first segment of modulation symbols, and spreading sequence component 335-m may apply a different spreading sequence to the mth segment of modulation symbols. In some cases, the spreading sequences may make the spread modulation symbol segments orthogonal, or quasi-orthogonal, to each other. In some cases, a spreading sequence may further be unique to the UE, such that a receiving device (e.g., a base station) may distinguish ML-RSMA transmissions from multiple UEs using the same resources, such as by NOMA techniques. In some cases, the spreading sequences may be determined based on a spreading sequence codebook. The UE may then apply a gain 340 to each layer 330 (e.g., gain g ₁ 340-a may be applied to the first layer 330-a and gain g _m 340-m may be applied to the mth layer 330-m) prior to recombining the spread symbols of the layers 330.

The UE may send the combined, spread symbols to the scrambling component 345. The scrambling component may apply a scrambling sequence to the spread symbols. The scrambling sequence may be UE-specific. In some cases, the scrambling sequence may be longer than the spreading sequences applied by the spreading sequence components 335.

The UE may provide the scrambled symbols to the tone interleaving component 350 and the tone mapper 355. The tone interleaving component 350 and the tone mapper 355 may interleave the map the time-domain symbols to tones corresponding to one or more symbol periods assigned for the ML-RSMA transmission. Based on the spreading, modulated symbols may be repeated with scrambling. In some cases, the tone interleaving component 350 and the tone mapper 355 may assign repeated modulated symbols to adjacent time/frequency resources. In some other examples, the tone interleaving component 350 and the tone mapper 355 may assign repeated modulated symbols to non-adjacent time/frequency resources. In some cases, the tone interleaving component 350 and the tone mapper 355 may group resource elements (REs) and repeated modulated symbols. The tone interleaving component 350 and the tone mapper 355 may generate frequency domain signals after the tone interleaving and mapping.

The waveform component 360 may perform an inverse fast Fourier transform (IFFT) on the frequency domain signals to generate a time domain waveform, such as a NOMA CP/DFT-s-OFDM waveform for uplink transmission. The UE may transmit the waveform via power amplifiers and antennas to a base station using the frequency and time resources identified for the uplink transmission of the uplink data by the UE. In some cases, the frequency and time resources may be NOMA resources, such as the NOMA resources 215 described in FIG. 2. A base station receiving NOMA uplink transmission from two or more UEs may decode each of the NOMA transmissions in accordance with NOMA techniques, such as SIC. In some cases, reference signal transmissions of the UEs, control signal transmissions, or combinations thereof, may assist the base station in decoding the multiple concurrent transmissions. As indicated above, different NOMA slot formats may provide locations for DMRS symbols, control channel symbols, and other transmissions.

FIGs. 4A, 4B, and 4C illustrate examples of NOMA slot formats that include configured demodulation reference signal (DMRS) symbols that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. In some examples, NOMA slot formats that include configured demodulation reference signal (DMRS) symbols may be implemented in aspects of

wireless communications system

100 or 200.

In the example of FIG. 4A, NOMA slot format 400 may include one or more DMRS symbols 405, a number of physical uplink shared channel (PUSCH) symbols 410, and optionally one or more physical downlink control channel (PDCCH) or physical downlink shared channel (PDSCH) symbols 415. The DMRS symbol (s) 405, in this example, are located at a start of the slot or TTI, and may assist a receiving base station in demodulating the PUSCH symbols 410.

In other cases, such as in the example of FIG. 4B, NOMA slot format 425 may include one or more DMRS symbols 430 that are located later within a slot, with a first set of PUSCH symbols 435-a and a second set of PUSCH symbols 435-b located on either side of the DMRS symbols 430. This example NOMA slot format 425 may also optionally include one or more PDCCH/PDSCH symbols 440. The DMRS symbol (s) 430, in this example, are located relatively later in the slot, and may assist a receiving base station in demodulating the PUSCH symbols 435. In some cases, a base station may configure some UEs with the slot format 400, and to help mitigate collision of DMRS transmissions, may configure other UEs with slot format 425. Thus, for NOMA UEs sharing the same PUSCH resources, their DMRS can be transmitted in different symbol locations of the same slot.

In still other cases, such as in the example of FIG. 4C, NOMA slot format 450 may include first DMRS symbol (s) 455-a that are located early within a slot, and second DMRS symbol (s) 455-b located later within the slot, with a first set of PUSCH symbols 460-a following the first DMRS symbol (s) 455-a and a second set of PUSCH symbols 460-b following DMRS symbol (s) 455-b. This example NOMA slot format 450 may also optionally include one or more PDCCH/PDSCH symbols 465. While the examples of FIGs. 4A through 4C show several examples of NOMA slot formats, numerous other examples of slot formats may be used in some systems, such as slot formats that have earlier or later DMRS locations, PDCCH/PDSCH symbols located earlier or later in slots or not configurable in a slot at all. Further, other symbols within slots may be configured for other transmissions, such as for UCI or DCI transmissions.

In some cases, for UEs whose DMRS symbols are front loaded with respect to PUSCH symbols in the slot, a receiving base station may detect their UE IDs, decode their data first, and perform SIC to decode other UE data. For UEs whose DMRS symbols are inserted between or after the PUSCH symbols, the receiving base station may detect them after canceling the interference of the UEs with front-loaded DMRS. In some cases, different DMRS sequences can be applied to different DMRS symbol locations. For example, front-loaded DMRS (e.g., DMRS symbols located relatively early in a slot) can use orthogonal sequences to simplify initial MUD, whereas non-orthogonal sequences can be applied to additional DMRS symbols (e.g., DMRS symbols located relatively later in a slot) to increase the size of resource pool of DMRS sequence. In some cases, to accommodate the different spectral efficiencies (SE) of a UE, additional DMRS symbols can also be configured and a UE may select a number of DMRS symbols to use based on a SE of the UE. Such different SEs of different UEs may occur when ML-RSMA is used. To help enable more reliable detection and channel estimation by a receiving base station, UEs with relatively high SE, such as a SE that is at or above a preconfigured threshold value, can choose to transmit additional DMRS using the additional DMRS symbols.

FIGs. 5A, 5B, and 5C illustrate examples of NOMA slot formats that include configured uplink control channel symbols that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. In some examples, NOMA slot formats that include configured uplink control channel symbols may be implemented in aspects of

wireless communications system

100 or 200.

In the example of FIG. 5A, NOMA slot format 500 may include one or more DMRS symbols 505, one or more short PUCCH symbols 510, a number of PUSCH symbols 515, and optionally one or more PDCCH/PDSCH symbols 520. The DMRS symbol (s) 505, in this example, are located at a start of the slot or TTI, and may assist a receiving base station in demodulating the PUSCH symbols 515. In the example of FIG. 5B, NOMA slot format 525 may include one or more short PUCCH symbols 530 followed by one or more DMRS symbols 535, a number of PUSCH symbols 540, and optionally one or more PDCCH/PDSCH symbols 545. The DMRS symbol (s) 535, in this example, are located relatively early in the slot, and again may assist a receiving base station in demodulating the PUSCH symbols 540. Numerous other examples of control channel information symbols may also be used, and these examples are provided for purposes of discussion and illustration only.

In some cases, uplink control channel information, such as provided in

short PUCCH symbols

510 and 530, may include information to enhance demodulation and decoding of NOMA transmissions at a receiving base station. For example, NOMA UEs with higher SE, reliability, or latency requirements may transmit a short PUCCH that may assist the base station in decoding the associated NOMA uplink transmission. In the example of FIG. 5C, a first NOMA transmission 555 may be transmitted by a first UE that may include DMRS symbol 565, short PUCCH symbol 570, and PUSCH symbols 575. Concurrently with the first NOMA transmission 555, a second UE may transmit a second NOMA transmission 560 using common wireless resources, which may include a DMRS symbol 580 and PUSCH symbols 585. In this case, the first UE may have a higher SE, reliability, or latency requirement and may transmit uplink control information via short PUCCH symbol 570. The uplink control information may allow a receiving base station to more reliably decode the first NOMA transmission 555 in the presence of the concurrently transmitted second NOMA transmission 560.

In some cases, the uplink control channel transmission may be a predefined sequence that carries limited information about the transmitting UE, and does not require cyclic redundancy check (CRC) or channel coding. The sequence may be selected based on a table of available sequences that are mapped to one or more NOMA transmission parameters (e.g., number of layers, spreading factor, modulation order, spreading sequence, scrambling sequence, UE ID, etc. ) . In other cases, the uplink control channel transmission may include a relatively small number of encoded bits that may indicate one or more transmission parameters, and that may include CRC and channel coding (e.g., Reed Muller coding) and that are transmitted with a relatively large spreading factor. The receiving base station, upon detecting the PUCCH, may can obtain side information (e.g., spreading factor, number of layers, modulation order, spreading sequence, scrambling sequence, UE ID, etc. ) about the transmitting UE, which may help to reduce the complexity associated blind decoding and simplify SIC. In some cases, UEs with both short PUCCH symbol 570 and DMRS symbol 565 may be treated as “strong” UEs and decoded first, and UEs without the short PUCCH symbol 570 can benefit from cancelled interference from the strong UEs.

In some cases, a base station may not successfully decode an uplink NOMA transmission from a UE. In such cases, feedback may be provided to the transmitting UE (e.g., HARQ ACK/NACK feedback) that indicates whether the uplink NOMA transmission is successfully received and that may prompt a retransmission by the UE in the event of unsuccessful reception at the receiving base station. In some cases, the base station may transmit a DCI transmission associated with uplink NOMA transmissions. Such a DCI transmission may be limited to DCI associated with NOMA transmissions, and may be referred to herein as compact DCI.

FIG. 6 illustrates an example of a NOMA slot format 600 that includes a downlink control information transmission that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. In some examples, NOMA slot format 600 that includes a downlink control information transmission may be implemented in aspects of

wireless communications system

100 or 200.

In this example, an initial transmission 605 may be transmitted by a UE as an uplink NOMA transmission that includes DMRS symbol (s) 615, PUSCH symbols 620, and optionally PDCCH/PDSCH symbol (s) 625. A receiving base station may attempt to receive and decode the initial transmission 605, and may not successfully decode the transmission. In such a case, the receiving base station may transmit a NACK feedback indication. In this example, the receiving base station may incorporate the NACK feedback indication in NOMA DCI 630 that is transmitted back to the UE. The UE, upon receiving the NOMA DCI 630, may transmit retransmission 610, which may include DMRS symbol (s) 635 and PUSCH symbols 640. The retransmission slot may also optionally include PDCCH/PDSCH symbol (s) 645. The NOMA DCI 630 may, additionally or alternatively, include other information, such as link adaptation or different NOMA operation mode information. The NOMA DCI 630, in some cases, may include indications of such feedback or other parameters. In some cases, to reduce the signaling overhead a compact NOMA DCI with simplified HARQ and compact DCI may be configured. In some cases, the NOMA DCI may include a payload that includes, for example, a slot format indication, link adaptation information (e.g. change of spreading factor, change of bundling size, multi-layer support, limited support for dynamic MCS, power control, multiplexing, etc. ) , group ACK/NACK information, a slot aggregation indication, or any combinations thereof. The UE, upon receiving the NOMA DCI, may format and transmit subsequent NOMA uplink transmissions in accordance with information in the NOMA DCI. In some cases, the NOMA DCI include one or more index values of a configuration table that maps a set of configuration parameters to the one or more index values.

FIG. 7 illustrates an example of NOMA slot formats for slot aggregation 700 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. In some examples, NOMA slot formats for slot aggregation 700 may be implemented in aspects of

wireless communications system

100 or 200.

In this example, two NOMA slots may be configured, including a first NOMA slot (slot k) 715, and a second NOMA slot (slot k+1) 720. A first UE group may be configured without slot aggregation, and may transmit NOMA transmissions 710 which may, for example, have a spreading factor of two for the first NOMA slot 715, which may include DMRS symbol (s) 725, PUSCH symbols 730, and optional PDCCH/PDSCH symbol (s) 735. A second UE croup may be configured with slot aggregation, and may transmit NOMA transmissions 705 which may, for example, have a spreading factor of four and be aggregated across the first NOMA slot 715 and the second NOMA slot 720. In this example, aggregated NOMA transmissions 705 may include DMRS symbol (s) 740, PUSCH symbols 745, and optional PDCCH/PDSCH symbol (s) 750 in the first NOMA slot 715 and DMRS symbol (s) 755, PUSCH symbols 760, and optional PDCCH/PDSCH symbol (s) 765 in the second NOMA slot 720.

Such slot aggregation can be treated as a method to implement nested spreading, which may allow different spreading factors for different UE groups, and thus the different UE groups can occupy a different number of symbols. In some cases, slot aggregation can be combined with other link adaptation methods, and may allow for the joint use of power control and rate adaptation in UE grouping.

In some cases, slot formats for adjacent aggregated NOMA slots may be the same or different. FIGs. 8A and 8B illustrate examples of a NOMA slot formats for slot aggregation that support slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. In some examples, NOMA slot formats for slot aggregation may be implemented in aspects of

wireless communications system

100 or 200. In these examples, different combinations of slot formats may be implemented for different NOMA slots.

FIG. 8A illustrates a slot aggregation 800 of a first slot (slot k) 805 and a second slot (slot k+1) 810. The first slot 805 may have a first slot format 815 that may be any available slot format, such as one of the exemplary slot formats discussed above. The second slot 810 may have a different slot format that includes only PUSCH symbols 820. In such a case, one or more DMRS symbols from the first slot 805 may be used for demodulation of the second slot 810. Similarly, FIG. 8B illustrates a slot aggregation 825 of a first slot (slot k) 830 and a second slot (slot k+1) 835. The first slot 830 may have a first slot format 840 that may be any available slot format, such as one of the exemplary slot formats discussed above. The second slot 835 may have a different slot format that includes PUSCH symbols 845 and PDCCH/PDSCH symbols 850. In some cases, the aggregated slots may be discontinuous in time, and may use different frequency, or spatial resources. In some cases, the number of time/frequency resources for PUSCH may be identical across the aggregated slots.

FIG. 9 illustrates an example of a process flow 900 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. In some examples, process flow 900 may implement aspects of

wireless communications system

100 or 200. Process flow 900 includes UE 115-c and base station 105-b, which may be respective examples of a UE 115 and a base station 105 as described herein.

The base station 105-b in this example, at 905, may configure NOMA slots. The configuration of NOMA slots may be based on various parameters, such as a number of UEs that may potentially transmit NOMA uplink transmissions, SE, reliability, or latency requirements of the UEs, resources available for NOMA transmissions, capabilities of UEs that are served by the base station 105-b, and the like. The base station 105-b may transmit NOMA slot configuration information 910 to the UE 115-c. In some cases, the slot format may be provided in a NOMA SFI that is transmitted to the UE 115-c via semi-static signaling (e.g., RRC signaling) or via dynamic signaling (e.g., via group PDCCH) .

At 915, the UE 115-c may configure parameters for uplink reference signal and control transmissions. In some cases, the UE 115-c may select a DMRS sequence for a DMRS transmission, in which a set of available DMRS sequences may be based at least in part on a location of configured DMRS symbols within a NOMA slot. In some cases, the UE 115-c may determine a SE (e.g., based on a number of ML-RSMA layers) , and may determine a number of DMRS symbols to use for DMRS transmissions based at least in part on the determined SE. In some cases, the UE 115-c may select a first number of DMRS symbols when the SE is below a threshold value, and may select a second number of DMRS symbols that are greater than the first number of DMRS symbols when the SE is at or above the threshold value. In some cases, the UE 115-c may determine whether to transmit uplink control information and may configure a uplink control transmission based on the determination. Such a determination may be based on a configuration at the UE, or a SE, reliability target, latency target, or combinations thereof, at the UE.

At 920, UE 115-c may generate a NOMA transmission. The NOMA transmission may include uplink data to be transmitted in PUSCH symbols, may include one or more DMRS sequences to be transmitted in one or more DMRS symbols, may include control information for transmission in one or more uplink control symbols, or any combination thereof. The UE 115-c may transmit the NOMA transmission 925 to the base station 105-b, which may receive and decode the transmission. In some cases, the base station 105-b may perform NOMA demodulation and decoding based on SIC/MUD using NOMA decoding techniques.

Optionally, at 930, the base station 105-b may configure NOMA DCI. As indicated above, the NOMA DCI may include, for example, feedback information, one or more parameters associated with NOMA uplink transmissions, or any combinations thereof. The base station 105-b may transmit the NOMA DCI 935 to the UE 115-c, which may receive and process the DCI accordingly.

The UE 115-c may optionally, at 940, configure parameters for uplink reference signal and control transmissions for a NOMA retransmission, in a manner similarly as discussed at block 915. In some cases, the NOMA DCI 935 may include different or updated parameters that may be used to configure retransmission parameters.

Optionally at 945, the UE may generate a NOMA retransmission. The NOMA retransmission may include the uplink data transmitted in the prior PUSCH symbols, may include one or more DMRS sequences to be transmitted in one or more DMRS symbols, may include control information for transmission in one or more uplink control symbols, or any combination thereof. The UE 115-c may transmit the NOMA retransmission 950 to the base station 105-b, which may receive and decode the retransmission.

FIG. 10 shows a block diagram 1000 of a device 1005 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The device 1005 may be an example of aspects of a UE 115 as described herein. The device 1005 may include a receiver 1010, a communications manager 1015, and a transmitter 1020. The device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to slot format and signaling in non-orthogonal multiple access wireless communications, etc. ) . Information may be passed on to other components of the device 1005. The receiver 1010 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The receiver 1010 may utilize a single antenna or a set of antennas.

The communications manager 1015 may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, format one or more NOMA uplink transmissions based on the NOMA SFI, and transmit the one or more NOMA uplink transmissions to the base station. The communications manager 1015 may be an example of aspects of the communications manager 1310 described herein.

The communications manager 1015, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 1015, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 1015, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 1015, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 1015, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1020 may transmit signals generated by other components of the device 1005. In some examples, the transmitter 1020 may be collocated with a receiver 1010 in a transceiver module. For example, the transmitter 1020 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The transmitter 1020 may utilize a single antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a device 1105 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The device 1105 may be an example of aspects of a device 1005 or a UE 115 as described herein. The device 1105 may include a receiver 1110, a communications manager 1115, and a transmitter 1130. The device 1105 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1110 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to slot format and signaling in non-orthogonal multiple access wireless communications, etc. ) . Information may be passed on to other components of the device 1105. The receiver 1110 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The receiver 1110 may utilize a single antenna or a set of antennas.

The communications manager 1115 may be an example of aspects of the communications manager 1015 as described herein. The communications manager 1115 may include a NOMA configuration manager 1120 and a NOMA transmission manager 1125. The communications manager 1115 may be an example of aspects of the communications manager 1310 described herein.

The NOMA configuration manager 1120 may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof.

The NOMA transmission manager 1125 may format one or more NOMA uplink transmissions based on the NOMA SFI and transmit the one or more NOMA uplink transmissions to the base station.

The transmitter 1130 may transmit signals generated by other components of the device 1105. In some examples, the transmitter 1130 may be collocated with a receiver 1110 in a transceiver module. For example, the transmitter 1130 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The transmitter 1130 may utilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a communications manager 1205 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The communications manager 1205 may be an example of aspects of a communications manager 1015, a communications manager 1115, or a communications manager 1310 described herein.. The communications manager 1205 may include a NOMA configuration manager 1210, a NOMA transmission manager 1215, a DMRS component 1220, an UCI component 1225, a DCI component 1230, and a slot aggregation component 1235. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The NOMA configuration manager 1210 may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. In some examples, the NOMA configuration manager 1210 may receive the NOMA SFI via a semi-static downlink assignment from the base station. In some examples, the NOMA configuration manager 1210 may receive the NOMA SFI via RRC signaling. In some examples, the NOMA configuration manager 1210 may receive the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station. In some examples, the NOMA configuration manager 1210 may receive a first portion of the NOMA SFI via a semi-static downlink assignment from the base station and receiving a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station. In some cases, the one or more NOMA uplink transmissions are autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station.

The NOMA transmission manager 1215 may format one or more NOMA uplink transmissions based on the NOMA SFI. In some examples, the NOMA transmission manager 1215 may transmit the one or more NOMA uplink transmissions to the base station.

The DMRS component 1220 may identify the one or more DMRS symbols within the one or more slots based on the NOMA SFI. In some examples, the DMRS component 1220 may select a DMRS sequence for the one or more DMRS transmissions based on a location of the one or more DMRS symbols within the one or more slots. In some examples, the DMRS component 1220 may identify a spectral efficiency of the uplink transmissions to the base station. In some examples, the DMRS component 1220 may select a first number of DMRS symbols when a value of the spectral efficiency is below a threshold value and a second number of DMRS symbols when the value of the spectral efficiency meets or exceeds the threshold value, where the second number of DMRS symbols is greater than the first number of DMRS symbols. In some cases, a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.

The UCI component 1225 may identify an uplink control channel symbol within the one or more slots based on the NOMA SFI. In some examples, the UCI component 1225 may determine that an uplink control channel transmission is to be transmitted to the base station, the uplink control channel transmission indicating one or more parameters associated with one or more uplink data NOMA transmissions within the one or more slots.

In some examples, the UCI component 1225 may format the uplink control channel transmission within the uplink control channel symbol. In some cases, the uplink control channel transmission includes a predetermined sequence that indicates values for the one or more parameters. In some cases, the predetermined sequence is selected from a set of available sequences based on the values for the one or more parameters. In some cases, the predetermined sequence is transmitted in an absence of a CRC or channel coding. In some cases, the uplink control channel transmission includes a set of encoded bits that indicate values for the one or more parameters. In some cases, the set of encoded bits are transmitted with a CRC and channel coding. In some cases, the one or more parameters indicate, for the one or more uplink data NOMA transmissions, one or more of a spreading factor, a number of RMSI layers, a modulation order, or any combinations thereof. In some cases, the one or more parameters provide enhanced successive interference cancellation (SIC) for the base station.

The DCI component 1230 may receive, from the base station, DCI that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. In some cases, the DCI includes one or more index values of a configuration table that maps a set of configuration parameters to the one or more index values. In some cases, the DCI includes ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.

The slot aggregation component 1235 may different slots of the two or more aggregated slots have different NOMA slot formats. In some cases, the NOMA SFI further indicates slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots. In some cases, the slot aggregation information indicates a spreading factor is to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.

FIG. 13 shows a diagram of a system 1300 including a device 1305 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The device 1305 may be an example of or include the components of device 1005, device 1105, or a UE 115 as described herein.. The device 1305 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1310, an I/O controller 1315, a transceiver 1320, an antenna 1325, memory 1330, and a processor 1340. These components may be in electronic communication via one or more buses (e.g., bus 1345) .

The communications manager 1310 may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, format one or more NOMA uplink transmissions based on the NOMA SFI, and transmit the one or more NOMA uplink transmissions to the base station.

The I/O controller 1315 may manage input and output signals for the device 1305. The I/O controller 1315 may also manage peripherals not integrated into the device 1305. In some cases, the I/O controller 1315 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 1315 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 1315 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 1315 may be implemented as part of a processor. In some cases, a user may interact with the device 1305 via the I/O controller 1315 or via hardware components controlled by the I/O controller 1315.

The transceiver 1320 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1320 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1320 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1325. However, in some cases the device may have more than one antenna 1325, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1330 may include RAM and ROM. The memory 1330 may store computer-readable, computer-executable code 1335 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1330 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1340 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1340 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 1340. The processor 1340 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1330) to cause the device 1305 to perform various functions (e.g., functions or tasks supporting slot format and signaling in non-orthogonal multiple access wireless communications) .

The code 1335 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1335 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1335 may not be directly executable by the processor 1340 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 14 shows a block diagram 1400 of a device 1405 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The device 1405 may be an example of aspects of a base station 105 as described herein. The device 1405 may include a receiver 1410, a communications manager 1415, and a transmitter 1420. The device 1405 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1410 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to slot format and signaling in non-orthogonal multiple access wireless communications, etc. ) . Information may be passed on to other components of the device 1405. The receiver 1410 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The receiver 1410 may utilize a single antenna or a set of antennas.

The communications manager 1415 may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE, monitor uplink transmissions in the one or more slots, and decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration. The communications manager 1415 may be an example of aspects of the communications manager 1710 described herein.

The communications manager 1415, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 1415, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 1415, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 1415, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 1415, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1420 may transmit signals generated by other components of the device 1405. In some examples, the transmitter 1420 may be collocated with a receiver 1410 in a transceiver module. For example, the transmitter 1420 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The transmitter 1420 may utilize a single antenna or a set of antennas.

FIG. 15 shows a block diagram 1500 of a device 1505 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The device 1505 may be an example of aspects of a device 1405 or a base station 105 as described herein. The device 1505 may include a receiver 1510, a communications manager 1515, and a transmitter 1535. The device 1505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to slot format and signaling in non-orthogonal multiple access wireless communications, etc. ) . Information may be passed on to other components of the device 1505. The receiver 1510 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The receiver 1510 may utilize a single antenna or a set of antennas.

The communications manager 1515 may be an example of aspects of the communications manager 1415 as described herein. The communications manager 1515 may include a NOMA configuration manager 1520, a NOMA transmission manager 1525, and a decoder 1530. The communications manager 1515 may be an example of aspects of the communications manager 1710 described herein.

The NOMA configuration manager 1520 may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof and transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE.

The NOMA transmission manager 1525 may monitor uplink transmissions in the one or more slots. The decoder 1530 may decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration.

The transmitter 1535 may transmit signals generated by other components of the device 1505. In some examples, the transmitter 1535 may be collocated with a receiver 1510 in a transceiver module. For example, the transmitter 1535 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The transmitter 1535 may utilize a single antenna or a set of antennas.

FIG. 16 shows a block diagram 1600 of a communications manager 1605 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The communications manager 1605 may be an example of aspects of a communications manager 1415, a communications manager 1515, or a communications manager 1710 described herein.. The communications manager 1605 may include a NOMA configuration manager 1610, a NOMA transmission manager 1615, a decoder 1620, a DMRS component 1625, an UCI component 1630, a DCI component 1635, and a slot aggregation component 1640. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The NOMA configuration manager 1610 may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. In some examples, the NOMA configuration manager 1610 may transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE. In some examples, the NOMA configuration manager 1610 may transmit, from the base station, the NOMA SFI via a semi-static downlink assignment. In some examples, the NOMA configuration manager 1610 may transmit the NOMA SFI via RRC signaling. In some examples, the NOMA configuration manager 1610 may transmit the NOMA SFI via dynamic signaling in a group common downlink control channel transmission. In some examples, the NOMA configuration manager 1610 may transmit a first portion of the NOMA SFI via a semi-static downlink assignment and transmitting a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission.

The NOMA transmission manager 1615 may monitor uplink transmissions in the one or more slots. The decoder 1620 may decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration.

The DMRS component 1625 may configure a DMRS sequence for the one or more DMRS transmissions based on a location of the one or more DMRS symbols within the one or more slots. In some cases, the NOMA slot configuration includes one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the set of UEs. In some cases, a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.

The UCI component 1630 may configure an uplink control channel symbol within the one or more slots. In some cases, an uplink control channel transmission received via the uplink control channel symbol includes a predetermined sequence that indicates values for one or more parameters of an associated uplink NOMA transmission. In some cases, the predetermined sequence is selected from a set of available sequences based on the values for the one or more parameters. In some cases, the one or more parameters indicate, for one or more uplink data NOMA transmissions, one or more of a spreading factor, number of transmission layers, a modulation order, or any combinations thereof. In some cases, the one or more parameters provide enhanced successive interference cancellation (SIC) for the base station.

The DCI component 1635 may transmit, to a first UE of the set of UEs, DCI that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. In some cases, the DCI includes one or more index values of a configuration table that maps a set of configuration parameters to the one or more index values. In some cases, the DCI includes ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.

The slot aggregation component 1640 may configure a slot aggregation for aggregation of the one or more NOMA uplink transmissions across two or more slots, and where the NOMA SFI includes slot aggregation information. In some cases, the slot aggregation information indicates a spreading factor is to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.

FIG. 17 shows a diagram of a system 1700 including a device 1705 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The device 1705 may be an example of or include the components of device 1405, device 1505, or a base station 105 as described herein. . The device 1705 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1710, a network communications manager 1715, a transceiver 1720, an antenna 1725, memory 1730, a processor 1740, and an inter-station communications manager 1745. These components may be in electronic communication via one or more buses (e.g., bus 1750) .

The communications manager 1710 may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof, transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE, monitor uplink transmissions in the one or more slots, and decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration.

The network communications manager 1715 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 1715 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 1720 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1720 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1720 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1725. However, in some cases the device may have more than one antenna 1725, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1730 may include RAM, ROM, or a combination thereof. The memory 1730 may store computer-readable code 1735 including instructions that, when executed by a processor (e.g., the processor 1740) cause the device to perform various functions described herein. In some cases, the memory 1730 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1740 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1740 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 1740. The processor 1740 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1730) to cause the device # {device} to perform various functions (e.g., functions or tasks supporting slot format and signaling in non-orthogonal multiple access wireless communications) .

The inter-station communications manager 1745 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1745 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1745 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

The code 1735 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1735 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1735 may not be directly executable by the processor 1740 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 18 shows a flowchart illustrating a method 1800 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 1800 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1800 may be performed by a communications manager as described with reference to FIGs. 10 to 13.In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1805, the UE may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 1805 may be performed according to the methods described herein. In some examples, aspects of the operations of 1805 may be performed by a NOMA configuration manager as described with reference to FIGs. 10 to 13.

In some cases, the one or more NOMA uplink transmissions are autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station. In some cases, the NOMA SFI is signaled via a semi-static downlink assignment from the base station. In some cases, the UE may receive the NOMA SFI via RRC signaling. In some cases, the UE may receive the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station. In some cases, the UE may receive a first portion of the NOMA SFI via a semi-static downlink assignment from the base station and receiving a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station.

At 1810, the UE may format one or more NOMA uplink transmissions based on the NOMA SFI. The operations of 1810 may be performed according to the methods described herein. In some examples, aspects of the operations of 1810 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

At 1815, the UE may transmit the one or more NOMA uplink transmissions to the base station. The operations of 1815 may be performed according to the methods described herein. In some examples, aspects of the operations of 1815 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

FIG. 19 shows a flowchart illustrating a method 1900 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 1900 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1900 may be performed by a communications manager as described with reference to FIGs. 10 to 13. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1905, the UE may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 1905 may be performed according to the methods described herein. In some examples, aspects of the operations of 1905 may be performed by a NOMA configuration manager as described with reference to FIGs. 10 to 13. In some cases, the one or more NOMA uplink transmissions are autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station.

At 1910, the UE may identify the one or more DMRS symbols within the one or more slots based on the NOMA SFI. The operations of 1910 may be performed according to the methods described herein. In some examples, aspects of the operations of 1910 may be performed by a DMRS component as described with reference to FIGs. 10 to 13.

At 1915, the UE may select a DMRS sequence for the one or more DMRS transmissions based on a location of the one or more DMRS symbols within the one or more slots. The operations of 1915 may be performed according to the methods described herein. In some examples, aspects of the operations of 1915 may be performed by a DMRS component as described with reference to FIGs. 10 to 13. In some cases, a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.

At 1920, the UE may format one or more NOMA uplink transmissions based on the NOMA SFI. The operations of 1920 may be performed according to the methods described herein. In some examples, aspects of the operations of 1920 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

At 1925, the UE may transmit the one or more NOMA uplink transmissions to the base station. The operations of 1925 may be performed according to the methods described herein. In some examples, aspects of the operations of 1925 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

FIG. 20 shows a flowchart illustrating a method 2000 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 2000 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 2000 may be performed by a communications manager as described with reference to FIGs. 10 to 13. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 2005, the UE may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 2005 may be performed according to the methods described herein. In some examples, aspects of the operations of 2005 may be performed by a NOMA configuration manager as described with reference to FIGs. 10 to 13. In some cases, the one or more NOMA uplink transmissions are autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station.

At 2010, the UE may identify a spectral efficiency of the uplink transmissions to the base station. The operations of 2010 may be performed according to the methods described herein. In some examples, aspects of the operations of 2010 may be performed by a DMRS component as described with reference to FIGs. 10 to 13.

At 2015, the UE may select a first number of DMRS symbols when a value of the spectral efficiency is below a threshold value and a second number of DMRS symbols when the value of the spectral efficiency meets or exceeds the threshold value, where the second number of DMRS symbols is greater than the first number of DMRS symbols. The operations of 2015 may be performed according to the methods described herein. In some examples, aspects of the operations of 2015 may be performed by a DMRS component as described with reference to FIGs. 10 to 13.

At 2020, the UE may format one or more NOMA uplink transmissions based on the NOMA SFI. The operations of 2020 may be performed according to the methods described herein. In some examples, aspects of the operations of 2020 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

At 2025, the UE may transmit the one or more NOMA uplink transmissions to the base station. The operations of 2025 may be performed according to the methods described herein. In some examples, aspects of the operations of 2025 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

FIG. 21 shows a flowchart illustrating a method 2100 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 2100 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 2100 may be performed by a communications manager as described with reference to FIGs. 10 to 13. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 2105, the UE may receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 2105 may be performed according to the methods described herein. In some examples, aspects of the operations of 2105 may be performed by a NOMA configuration manager as described with reference to FIGs. 10 to 13.

At 2110, the UE may format one or more NOMA uplink transmissions based on the NOMA SFI. The operations of 2110 may be performed according to the methods described herein. In some examples, aspects of the operations of 2110 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

At 2115, the UE may transmit the one or more NOMA uplink transmissions to the base station. The operations of 2115 may be performed according to the methods described herein. In some examples, aspects of the operations of 2115 may be performed by a NOMA transmission manager as described with reference to FIGs. 10 to 13.

At 2120, the UE may receive, from the base station, DCI that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. The operations of 2120 may be performed according to the methods described herein. In some examples, aspects of the operations of 2120 may be performed by a DCI component as described with reference to FIGs. 10 to 13. In some cases, the DCI includes one or more index values of a configuration table that maps a set of configuration parameters to the one or more index values. In some cases, the DCI includes ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.

At 2125, the UE may optionally transmit the retransmission of one or more NOMA uplink transmissions to the base station based at least in part on the DCI. The operations of 2125 may be performed according to the methods described herein. In some examples, aspects of the operations of 2125 may be performed by a DCI component as described with reference to FIGs. 10 to 13.

FIG. 22 shows a flowchart illustrating a method 2200 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 2200 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2200 may be performed by a communications manager as described with reference to FIGs. 14 to 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2205, the base station may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 2205 may be performed according to the methods described herein. In some examples, aspects of the operations of 2205 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17. In some cases, the NOMA slot configuration includes one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the set of UEs.

At 2210, the base station may transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE. The operations of 2210 may be performed according to the methods described herein. In some examples, aspects of the operations of 2210 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17.

At 2215, the base station may transmit, from the base station, the NOMA SFI via a semi-static downlink assignment. The operations of 2215 may be performed according to the methods described herein. In some examples, aspects of the operations of 2215 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17. In some cases, the base station may transmit the NOMA SFI via RRC signaling. In some cases, the base station may transmit the NOMA SFI via dynamic signaling in a group common downlink control channel transmission. In some cases, the base station may transmit a first portion of the NOMA SFI via a semi-static downlink assignment and transmitting a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission.

At 2220, the base station may monitor uplink transmissions in the one or more slots. The operations of 2220 may be performed according to the methods described herein. In some examples, aspects of the operations of 2220 may be performed by a NOMA transmission manager as described with reference to FIGs. 14 to 17.

At 2225, the base station may decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration. The operations of 2225 may be performed according to the methods described herein. In some examples, aspects of the operations of 2225 may be performed by a decoder as described with reference to FIGs. 14 to 17.

FIG. 23 shows a flowchart illustrating a method 2300 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 2300 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2300 may be performed by a communications manager as described with reference to FIGs. 14 to 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2305, the base station may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 2305 may be performed according to the methods described herein. In some examples, aspects of the operations of 2305 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17. In some cases, the NOMA slot configuration includes one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the set of UEs.

At 2310, the base station may configure a DMRS sequence for the one or more DMRS transmissions based on a location of the one or more DMRS symbols within the one or more slots. The operations of 2310 may be performed according to the methods described herein. In some examples, aspects of the operations of 2310 may be performed by a DMRS component as described with reference to FIGs. 14 to 17. In some cases, a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.

At 2315, the base station may transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE. The operations of 2315 may be performed according to the methods described herein. In some examples, aspects of the operations of 2315 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17.

At 2320, the base station may monitor uplink transmissions in the one or more slots. The operations of 2320 may be performed according to the methods described herein. In some examples, aspects of the operations of 2320 may be performed by a NOMA transmission manager as described with reference to FIGs. 14 to 17.

At 2325, the base station may decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration. The operations of 2325 may be performed according to the methods described herein. In some examples, aspects of the operations of 2325 may be performed by a decoder as described with reference to FIGs. 14 to 17.

FIG. 24 shows a flowchart illustrating a method 2400 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 2400 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2400 may be performed by a communications manager as described with reference to FIGs. 14 to 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2405, the base station may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 2405 may be performed according to the methods described herein. In some examples, aspects of the operations of 2405 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17.

At 2410, the base station may configure an uplink control channel symbol within the one or more slots. The operations of 2410 may be performed according to the methods described herein. In some examples, aspects of the operations of 2410 may be performed by an UCI component as described with reference to FIGs. 14 to 17. In some cases, an uplink control channel transmission received via the uplink control channel symbol includes a predetermined sequence that indicates values for one or more parameters of an associated uplink NOMA transmission.

At 2415, the base station may transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE. The operations of 2415 may be performed according to the methods described herein. In some examples, aspects of the operations of 2415 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17.

At 2420, the base station may monitor uplink transmissions in the one or more slots. The operations of 2420 may be performed according to the methods described herein. In some examples, aspects of the operations of 2420 may be performed by a NOMA transmission manager as described with reference to FIGs. 14 to 17.

At 2425, the base station may decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration. The operations of 2425 may be performed according to the methods described herein. In some examples, aspects of the operations of 2425 may be performed by a decoder as described with reference to FIGs. 14 to 17.

FIG. 25 shows a flowchart illustrating a method 2500 that supports slot format and signaling in non-orthogonal multiple access wireless communications in accordance with aspects of the present disclosure. The operations of method 2500 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2500 may be performed by a communications manager as described with reference to FIGs. 14 to 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2505, the base station may configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent UE NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof. The operations of 2505 may be performed according to the methods described herein. In some examples, aspects of the operations of 2505 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17.

At 2510, the base station may transmit, to each of a set of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE. The operations of 2510 may be performed according to the methods described herein. In some examples, aspects of the operations of 2510 may be performed by a NOMA configuration manager as described with reference to FIGs. 14 to 17.

At 2515, the base station may monitor uplink transmissions in the one or more slots. The operations of 2515 may be performed according to the methods described herein. In some examples, aspects of the operations of 2515 may be performed by a NOMA transmission manager as described with reference to FIGs. 14 to 17.

At 2520, the base station may decode two or more concurrent NOMA transmissions from two or more of the set of UEs based on the NOMA slot configuration. The operations of 2520 may be performed according to the methods described herein. In some examples, aspects of the operations of 2520 may be performed by a decoder as described with reference to FIGs. 14 to 17.

At 2525, the base station may transmit, to a first UE of the set of UEs, DCI that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof. The operations of 2525 may be performed according to the methods described herein. In some examples, aspects of the operations of 2525 may be performed by a DCI component as described with reference to FIGs. 14 to 17. In some cases, the DCI includes one or more index values of a configuration table that maps a set of configuration parameters to the one or more index values. In some cases, the DCI includes ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.

At 2530, the base station may optionally monitor uplink transmissions in one or more slots for retransmissions. The operations of 2515 may be performed according to the methods described herein. In some examples, aspects of the operations of 2515 may be performed by a NOMA transmission manager as described with reference to FIGs. 14 to 17.

It should be noted that the methods described above describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single carrier frequency division multiple access (SC-FDMA) , and other systems. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS- 856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .

An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) . LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs 115 with service subscriptions with the network provider. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc. ) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs 115 with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs 115 having an association with the femto cell (e.g., UEs 115 in a closed subscriber group (CSG) , UEs 115 for users in the home, and the like) . An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.

The wireless communications system 100 or systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device (PLD) , discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable read only memory (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communication at a user equipment (UE) , comprising:

receiving, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

formatting one or more NOMA uplink transmissions based at least in part on the NOMA SFI; and

transmitting the one or more NOMA uplink transmissions to the base station.
The method of claim 1, wherein the one or more NOMA uplink transmissions are autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station.
The method of claim 2, wherein the formatting the one or more NOMA uplink transmissions further comprises:

identifying the one or more DMRS symbols within the one or more slots based at least in part on the NOMA SFI; and

selecting a DMRS sequence for the one or more DMRS transmissions based at least in part on a location of the one or more DMRS symbols within the one or more slots.
The method of claim 3, wherein a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.
The method of claim 2, wherein the formatting the one or more NOMA uplink transmissions further comprises:

identifying a spectral efficiency of the uplink transmissions to the base station; and

selecting a first number of DMRS symbols when a value of the spectral efficiency is below a threshold value and a second number of DMRS symbols when the value of the spectral efficiency meets or exceeds the threshold value, wherein the second number of DMRS symbols is greater than the first number of DMRS symbols.
The method of claim 1, wherein the formatting the one or more NOMA uplink transmissions comprises:

identifying an uplink control channel symbol within the one or more slots based at least in part on the NOMA SFI;

determining that an uplink control channel transmission is to be transmitted to the base station, the uplink control channel transmission indicating one or more parameters associated with one or more uplink data NOMA transmissions within the one or more slots; and

formatting the uplink control channel transmission within the uplink control channel symbol.
The method of claim 6, wherein the uplink control channel transmission comprises a predetermined sequence that indicates values for the one or more parameters.
The method of claim 7, wherein the predetermined sequence is selected from a plurality of available sequences based on the values for the one or more parameters.
The method of claim 7, wherein the predetermined sequence is transmitted in an absence of a cyclic redundancy check (CRC) or channel coding.
The method of claim 6, wherein the uplink control channel transmission comprises a set of encoded bits that indicate values for the one or more parameters.
The method of claim 10, wherein the set of encoded bits are transmitted with a cyclic redundancy check (CRC) and channel coding.
The method of claim 6, wherein the one or more parameters indicate, for the one or more uplink data NOMA transmissions, one or more of a spreading factor, a number of RMSI layers, a modulation order, or any combinations thereof.
The method of claim 6, wherein the one or more parameters provide enhanced successive interference cancellation (SIC) for the base station.
The method of claim 1, further comprising:

receiving, from the base station, downlink control information (DCI) that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof.
The method of claim 14, wherein the DCI comprises one or more index values of a configuration table that maps a plurality of configuration parameters to the one or more index values.
The method of claim 14, wherein the DCI comprises ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.
The method of claim 1, wherein the NOMA SFI further indicates slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots.
The method of claim 17, wherein the slot aggregation information indicates a spreading factor is to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.
The method of claim 17, wherein:

different slots of the two or more aggregated slots have different NOMA slot formats.
The method of claim 1, wherein the receiving further comprises:

receiving the NOMA SFI via a semi-static downlink assignment from the base station.
The method of claim 1, wherein the receiving further comprises:

receiving the NOMA SFI via radio resource control (RRC) signaling.
The method of claim 1, wherein the receiving further comprises:

receiving the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station.
The method of claim 1, wherein the receiving further comprises:

receiving a first portion of the NOMA SFI via a semi-static downlink assignment from the base station and receiving a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission from the base station.
A method for wireless communication, comprising:

configuring, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent user equipment (UE) NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

transmitting, to each of a plurality of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE;

monitoring uplink transmissions in the one or more slots; and

decoding two or more concurrent NOMA transmissions from two or more of the plurality of UEs based at least in part on the NOMA slot configuration.
The method of claim 24, wherein the NOMA slot configuration includes one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the plurality of UEs.
The method of claim 25, wherein the configuring further comprises:

configuring a DMRS sequence for the one or more DMRS transmissions based at least in part on a location of the one or more DMRS symbols within the one or more slots.
The method of claim 26, wherein a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.
The method of claim 24, wherein the configuring further comprises:

configuring an uplink control channel symbol within the one or more slots.
The method of claim 28, wherein an uplink control channel transmission received via the uplink control channel symbol comprises a predetermined sequence that indicates values for one or more parameters of an associated uplink NOMA transmission.
The method of claim 29, wherein the predetermined sequence is selected from a plurality of available sequences based on the values for the one or more parameters.
The method of claim 29, wherein the one or more parameters indicate, for one or more uplink data NOMA transmissions, one or more of a spreading factor, number of transmission layers, a modulation order, or any combinations thereof.
The method of claim 29, wherein the one or more parameters provide enhanced successive interference cancellation (SIC) for the base station.
The method of claim 24, further comprising:

transmitting, to a first UE of the plurality of UEs, downlink control information (DCI) that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof.
The method of claim 33, wherein the DCI comprises one or more index values of a configuration table that maps a plurality of configuration parameters to the one or more index values.
The method of claim 33, wherein the DCI comprises ACK/NACK feedback information that indicates a retransmission of one or more prior uplink NOMA transmissions and one or more parameters for the retransmission.
The method of claim 24, wherein the configuring further comprises:

configuring a slot aggregation for aggregation of the one or more NOMA uplink transmissions across two or more slots, and wherein the NOMA SFI includes slot aggregation information.
The method of claim 36, wherein the slot aggregation information indicates a spreading factor is to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.
The method of claim 24, wherein the transmitting the NOMA SFI further comprises:

transmitting, from the base station, the NOMA SFI via a semi-static downlink assignment.
The method of claim 24, wherein the transmitting the NOMA SFI further comprises:

transmitting the NOMA SFI via radio resource control (RRC) signaling.
The method of claim 24, wherein the transmitting the NOMA SFI further comprises:

transmitting the NOMA SFI via dynamic signaling in a group common downlink control channel transmission.
The method of claim 24, wherein the transmitting the NOMA SFI further comprises:

transmitting a first portion of the NOMA SFI via a semi-static downlink assignment and transmitting a second portion of the NOMA SFI via dynamic signaling in a group common downlink control channel transmission.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

format one or more NOMA uplink transmissions based at least in part on the NOMA SFI; and

transmit the one or more NOMA uplink transmissions to the base station.
The apparatus of claim 42, wherein the one or more NOMA uplink transmissions are autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station.
The apparatus of claim 43, wherein the instructions are further executable by the processor to cause the apparatus to:

identify the one or more DMRS symbols within the one or more slots based at least in part on the NOMA SFI; and

select a DMRS sequence for the one or more DMRS transmissions based at least in part on a location of the one or more DMRS symbols within the one or more slots.
The apparatus of claim 44, wherein a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.
The apparatus of claim 43, wherein the instructions are further executable by the processor to cause the apparatus to:

identify a spectral efficiency of the uplink transmissions to the base station; and

select a first number of DMRS symbols when a value of the spectral efficiency is below a threshold value and a second number of DMRS symbols when the value of the spectral efficiency meets or exceeds the threshold value, wherein the second number of DMRS symbols is greater than the first number of DMRS symbols.
The apparatus of claim 42, wherein the instructions are further executable by the processor to cause the apparatus to:

identify an uplink control channel symbol within the one or more slots based at least in part on the NOMA SFI;

determine that an uplink control channel transmission is to be transmitted to the base station, the uplink control channel transmission indicating one or more parameters associated with one or more uplink data NOMA transmissions within the one or more slots; and

format the uplink control channel transmission within the uplink control channel symbol.
The apparatus of claim 42, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from the base station, downlink control information (DCI) that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof.
The apparatus of claim 48, wherein the DCI comprises one or more index values of a configuration table that maps a plurality of configuration parameters to the one or more index values.
The apparatus of claim 42, wherein the NOMA SFI further indicates slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots.
The apparatus of claim 50, wherein the slot aggregation information indicates a spreading factor is to be applied to spread the one or more NOMA uplink transmissions across two or more aggregated slots.
The apparatus of claim 50, wherein different slots of the two or more aggregated slots have different NOMA slot formats.
An apparatus for wireless communication, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent user equipment (UE) NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

transmit, to each of a plurality of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE;

monitor uplink transmissions in the one or more slots; and

decode two or more concurrent NOMA transmissions from two or more of the plurality of UEs based at least in part on the NOMA slot configuration.
The apparatus of claim 53, wherein the NOMA slot configuration includes one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the plurality of UEs.
The apparatus of claim 54, wherein the instructions are further executable by the processor to cause the apparatus to:

configure a DMRS sequence for the one or more DMRS transmissions based at least in part on a location of the one or more DMRS symbols within the one or more slots.
The apparatus of claim 55, wherein a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.
The apparatus of claim 53, wherein the instructions are further executable by the processor to cause the apparatus to:

configure an uplink control channel symbol within the one or more slots.
The apparatus of claim 57, wherein an uplink control channel transmission received via the uplink control channel symbol comprises a predetermined sequence that indicates values for one or more parameters of an associated uplink NOMA transmission.
The apparatus of claim 53, wherein the instructions are further executable by the processor to cause the apparatus to:

transmit, to a first UE of the plurality of UEs, downlink control information (DCI) that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof.
The apparatus of claim 53, wherein the configuring further comprises:

configure a slot aggregation for aggregation of the one or more NOMA uplink transmissions across two or more slots, and wherein the NOMA SFI includes slot aggregation information.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for receiving, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

means for formatting one or more NOMA uplink transmissions based at least in part on the NOMA SFI; and

means for transmitting the one or more NOMA uplink transmissions to the base station.
The apparatus of claim 61, wherein the one or more NOMA uplink transmissions are autonomous uplink transmissions from the UE, and the NOMA SFI indicates one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the UE to the base station.
The apparatus of claim 62, further comprising:

means for identifying the one or more DMRS symbols within the one or more slots based at least in part on the NOMA SFI; and

means for selecting a DMRS sequence for the one or more DMRS transmissions based at least in part on a location of the one or more DMRS symbols within the one or more slots.
The apparatus of claim 63, wherein a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.
The apparatus of claim 62, further comprising:

means for identifying a spectral efficiency of the uplink transmissions to the base station; and

means for selecting a first number of DMRS symbols when a value of the spectral efficiency is below a threshold value and a second number of DMRS symbols when the value of the spectral efficiency meets or exceeds the threshold value, wherein the second number of DMRS symbols is greater than the first number of DMRS symbols.
The apparatus of claim 61, further comprising:

means for identifying an uplink control channel symbol within the one or more slots based at least in part on the NOMA SFI;

means for determining that an uplink control channel transmission is to be transmitted to the base station, the uplink control channel transmission indicating one or more parameters associated with one or more uplink data NOMA transmissions within the one or more slots; and

means for formatting the uplink control channel transmission within the uplink control channel symbol.
The apparatus of claim 61, further comprising:

means for receiving, from the base station, downlink control information (DCI) that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof.
The apparatus of claim 61, wherein the NOMA SFI further indicates slot aggregation information for aggregation of the one or more NOMA uplink transmissions across two or more slots.
An apparatus for wireless communication, comprising:

means for configuring, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent user equipment (UE) NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

means for transmitting, to each of a plurality of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE;

means for monitoring uplink transmissions in the one or more slots; and

means for decoding two or more concurrent NOMA transmissions from two or more of the plurality of UEs based at least in part on the NOMA slot configuration.
The apparatus of claim 69, wherein the NOMA slot configuration includes one or more demodulation reference signal (DMRS) symbols within the one or more slots configured for DMRS transmissions from the plurality of UEs.
The apparatus of claim 70, further comprising:

means for configuring a DMRS sequence for the one or more DMRS transmissions based at least in part on a location of the one or more DMRS symbols within the one or more slots.
The apparatus of claim 71, wherein a first set of orthogonal DMRS sequences are configured for DMRS symbols located in a first subset of symbols within the one or more slots and a second set of non-orthogonal DMRS sequences are configured for DMRS symbols located in a second subset of symbols within the one or more slots, the first subset of symbols being earlier in the one or more slots than the second subset of symbols.
The apparatus of claim 69, further comprising:

means for configuring an uplink control channel symbol within the one or more slots.
The apparatus of claim 69, further comprising:

means for transmitting, to a first UE of the plurality of UEs, downlink control information (DCI) that indicates one or more of a NOMA slot format parameter, a link adaptation parameter, acknowledgment/negative-acknowledgment (ACK/NACK) feedback, a slot aggregation parameter, or any combinations thereof.
The apparatus of claim 69, further comprising:

means for configuring a slot aggregation for aggregation of the one or more NOMA uplink transmissions across two or more slots, and wherein the NOMA SFI includes slot aggregation information.
A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE) , the code comprising instructions executable by a processor to:

receive, from a base station, a non-orthogonal multiple access (NOMA) slot format indication (SFI) for transmission of NOMA uplink transmissions in one or more slots, the NOMA SFI indicating one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

format one or more NOMA uplink transmissions based at least in part on the NOMA SFI; and

transmit the one or more NOMA uplink transmissions to the base station.
A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:

configure, at a base station, a non-orthogonal multiple access (NOMA) slot configuration for concurrent user equipment (UE) NOMA uplink transmissions to the base station in one or more slots, the NOMA slot configuration including one or more uplink symbols within the one or more slots that are configured for reference signal transmissions, control information transmissions, or combinations thereof;

transmit, to each of a plurality of UEs, a NOMA slot format indication (SFI) that indicates the NOMA slot configuration for NOMA uplink transmissions from each UE;

monitor uplink transmissions in the one or more slots; and

decode two or more concurrent NOMA transmissions from two or more of the plurality of UEs based at least in part on the NOMA slot configuration.