WO2025200190A1

WO2025200190A1 - Method and apparatus for communications

Info

Publication number: WO2025200190A1
Application number: PCT/CN2024/105902
Authority: WO
Inventors: Yu Cao; Ming Jia; Jianglei Ma; Xiaoyan Bi
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2024-03-27
Filing date: 2024-07-17
Publication date: 2025-10-02
Anticipated expiration: 2026-09-27
Also published as: WO2025200190A9

Abstract

Embodiments of the present application provide a method and an apparatus for communication. In the present application, a solution that use one codeword (CW) map to a number of transmission layers is proposed. The scheme considers a joint CW to QAM and layer mapping solution. The basic idea is to map the more important bits of the codeword from the encoding process to higher reliability bits based on both bit location of modulation symbol and layer index. a ranking of the reliability (or the experienced channel quality) of the combination of layer index and modulation symbol is needed. In order for the BS and user to understand in the same way about the ranking results as well as understand how the joint CW to QAM and layer mapping is done, BS may need to indicate information regarding the ranking and/or parameters used for the joint mapping scheme. The present application proposes different method and signaling to indicate ranking and other parameters for joint CW to QAM and layer mapping process.

Description

METHOD AND APPARATUS FOR COMMUNICATIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to, international patent application No. PCT/CN2024/084184, entitled “METHOD AND APPARATUS FOR COMMUNICATIONS” , filed on March 27, 2024 and hereby incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments of the present invention relate to the field of wireless technologies, and more specifically, to a method and an apparatus for communications.

BACKGROUND

In future wireless communications, multiple input multiple output (MIMO) may have transmitter and/or receiver equipped with large number of antennas and support transmission over a large number of transmission layers. The channel quality among different transmission layers may significantly vary. One potential solution to codeword (CW) -to-layer mapping scheme is to use one CW map to each transmission layer. This allows maximizing throughput when accurate link adaptation is available. However, the scheme may incur significant overhead to the system, and can be impractical especially with large number of transmission layers. The overhead may include: hybrid automatic repeat request (HARQ) feedback overhead, HARQ process management overhead, signaling overhead, channel state information (CSI) feedback overhead. In addition, code block (CB) length can be very different for different layers, which may impact performance for some short-length CB, and also makes segmentation more complicated.

Therefore, an urgent technical problem that a codeword to layer mapping in a MIMO system, especially equipped with a larger number of antennas supporting a larger number of transmission layers, needs to be solved to improve system performance in many aspects.

SUMMARY

Embodiments of the present application provide a method and an apparatus for communications, which provides an efficient, robust and low overhead solution for a codeword to layer mapping for MIMO communications that has a large number of transmission layers.

According to a first aspect, there is provided a method for communications, and the method may be applied to a network side, for example, a base station (BS) or a component (for example, a circuit, a chip, or a chip system) in the BS. The method may include: mapping, based on mapping information, a coded bit sequence including a plurality of coded bits to modulation symbols and L transmission layers, where the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol, L is an integer greater than one; and transmitting first information used for determining the mapping information.

In a proposed solution provided by this application, a coded bit sequence is mapped, based on mapping information, to modulation symbols and multiple transmission layers by a first device. Then the first device needs to transmit first information used for determined the mapping information to a second device, for example, a UE, so that the first device and the second device have same understanding about how a joint codeword to modulation and transmission layer mapping is done. In addition, the mapping information is associated with a combination of a transmission layer and a bit location. Based on the mapping information, more important coded bits can be mapped to higher locations in terms of both a modulation bit location and a transmission layer location. In this way, the more important coded bits are better protected, which yields better decoding performance. Besides, the proposed solution also reduces complexity and signaling of the mapping procedure.

According to a second aspect, there is provided a method for communications, and the method may be applied at a terminal side, for example, a terminal or a module in a terminal, a circuit or a chip (for example, a modem (modem) chip, also referred to as a baseband (baseband) chip, or a system on chip (system on chip, SoC) chip or a system in package (system in package, SIP) chip that includes a modem core) that is responsible for a communication function in a terminal. The method may include: receiving first information, where the first information is used for determining mapping information, the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol; and demodulating, based on mapping information, a signal transmitted via L transmission layers, L is an integer greater than one.

The technical effects in the second aspect can be referred to those in the first aspect, which are not repeated.

In an implementation of the first aspect or the second aspect, the L transmission layers are mapped to one codeword.

In an implementation of the first aspect or the second aspect, the first information indicates a ranking of the combination.

This implementation is one of the most accurate ways to indicate a ranking of a combination.

In an implementation of the first aspect or the second aspect, the first information indicates a ranking among all possible rankings of the combinations.

In an implementation of the first aspect or the second aspect, the first information indicates a value corresponding to a first permutation pattern, the first permutation pattern corresponds to a first ranking of the combination, and the first permutation pattern is one of multiple permutation patterns that correspond to multiple rankings of the combination in a one-to-one relationship.

In this implementation, based on a one-to-one relationship, between multiple permutation patterns and multiple values, first information indicates a first permutation pattern by indicating a value corresponding to the first permutation pattern. The first permutation pattern represents a possible ranking of a combination. Since a small number of bits can indicate all of the multiple permutation patterns, this implementation can reduce overhead of indicating a ranking of a combination.

In an implementation of the first aspect or the second aspect, the first information indicates a ranking of the L transmission layers.

This implementation can be used when there is a preconfigured rule used, and overhead of indicating a ranking of a combination can be reduced.

In an implementation of the first aspect or the second aspect, the ranking of the L transmission layers and a preconfigured rule are used jointly to determine a ranking of the combination, and the mapping information is determined based on the ranking of the combination.

In an implementation of the first aspect or the second aspect, the first information indicates a ranking of more than one transmission layer groups, each transmission layer group comprises one or more transmission layers in the L transmission layers, and each transmission layer is comprised in one transmission layer group.

In an implementation of the first aspect or the second aspect, the ranking of the more than one transmission layer group and a preconfigured rule are used jointly to determine a ranking of the combination, and the mapping information is determined based on the ranking of the combination.

This implementation can be used when there is a preconfigured rule used. Besides, overhead of indicating a ranking of a combination can be further reduced due to joint use of both the preconfigured rule and grouping of L transmission layer.

In an implementation of the first aspect or the second aspect, the more than one transmission layer group is preconfigured.

In this implementation, since more than one transmission layer group is preconfigured, signaling to keep same understanding of transmission layer groups between a network device and a terminal is saved.

In an implementation of the first aspect or the second aspect, the first information further comprises one or more of:a quantity of transmission layers comprised in each transmission layer group; or a quantity of the more than one transmission layer groups.

In an implementation of the first aspect or the second aspect, the first information indicates modulation schemes for each of the L transmission layers or for each of transmission layer groups.

In an implementation of the first aspect or the second aspect, the first information, a preconfigured rule and a third rule are used jointly to determine a ranking of the combination, the third rule includes that a priority of a first transmission layer in the L transmission layers that adopts a modulation scheme corresponding to a higher modulation order is higher than a priority of a second transmission layer in the L transmission layers that adopts a modulation scheme corresponding to a lower modulation order, or the third rule includes that a priority of a firs transmission layer group in more than one transmission layer group that adopts a modulation scheme corresponding to a higher modulation order is higher than a priority of a second transmission layer group in more than one transmission layer group that adopts a modulation scheme corresponding to a lower modulation order; and the mapping information is determined based on the ranking of the combination.

In this implementation, a preconfigured rule and a third rule are joint used to reduce overhead of indicating a ranking of a combination.

In an implementation of the first aspect or the second aspect, the first information is used further for indicating a ranking of transmission layers adopting a same modulation scheme; or the first information is used further for indicating a ranking of transmission layer groups adopting a same modulation scheme.

This implementation is used based on the previous implementation. If different transmission layers or transmission layer groups adopt a same modulation scheme, first information further indicates a ranking of the transmission layers or transmission layer groups adopting the same modulation scheme so that the ranking of the combination can be determined.

In an implementation of the first aspect or the second aspect, the preconfigured rule comprises: a first rule based on which priority of the bit location of the modulation symbol is higher than priority of the transmission layer; or a second rule based on which priority of the transmission layer is higher than priority of the bit location of the modulation symbol.

This implementation provides two kinds of preconfigured rules. A preconfigured rule based indication obtains the minimum signaling overhead and capture majority of system gain.

In an implementation of the first aspect or the second aspect, the method further comprises: transmitting second information, the second information is used for indicating the first rule or the second rule.

In this implementation, if there is more than one preconfigured rule, signaling between a network device and a terminal that indicates which preconfigured rule is used to determine the ranking of the combination is needed. This implementation can achieve a tradeoff between full flexibility and signaling overhead.

In an implementation of the first aspect or the second aspect, the first information is used for indicating a subblock interleaving pattern f (i) associated with a ranking of the combination, the subblock interleaving pattern f (i) represent an ordering of a subblock i among all subblocks, the subblock i is a sub-sequence of a coded bit sequence to be mapped to a transmission layer and a bit location of a modulation symbol or to be mapped to a transmission layer group and a bit location of a modulation symbol.

In this implementation, first information indicates a subblock interleaving pattern that can be used to map a coded bit sequence to modulation symbols and L transmission layers. This is one of the most flexible and accurate ways to indicate a ranking of a combination, and captures the maximum gain. In addition, the subblock interleaver pattern indicated by the first information can be directly used by the BS or UE for the mapping or demapping of the coded bit sequence to modulation symbols and transmission layers.

In an implementation of the first aspect or the second aspect, the method further includes: mapping the coded bit sequence to modulation symbols and the L transmission layers based on the subblock interleaving pattern.

In an implementation of the first aspect or the second aspect, the subblock interleaving pattern denoted with f (i) indicates a location of a first combination with an index i in the ranking of all combinations, i is an integer; and the first combination comprises any one of: a combination of a bit location of a modulation symbol and a transmission layer; a combination of a bit location group of a modulation symbol and a transmission layer; a combination of a bit location of a modulation symbol and a transmission layer group; a combination of a bit location group pf a modulation symbol and a transmission layer group.

In an implementation of the first aspect or the second aspect, the bit location group comprises every two adjacent bit locations with the same priority in a modulation symbol.

In this implementation, grouping of bit locations of a modulation symbol further reduce overhead of indicating a ranking of a combination, and has no performance loss with the case without grouping of bit locations of the modulation symbol.

In an implementation of the first aspect or the second aspect, the ranking of the combination comprises a ranking of the combination in reliability.

In above implementations, a ranking of a combination may be a ranking on reliability of channel quality of the combination.

According to a third aspect, a communication apparatus is described. The communication apparatus has a function of implementing the first aspect. For example, the communication apparatus includes a corresponding module, unit, or means for performing operations in the first aspect. The module, unit, or means may be specifically implemented by using software, may be implemented by using hardware, or may be implemented by using software in combination with hardware.

According to a fourth aspect, a communication apparatus is described. The communication apparatus has a function of implementing the second aspect. For example, the communication apparatus includes a corresponding module, unit, or means for performing operations in the second aspect. The module, unit, or means may be specifically implemented by using software, may be implemented by using hardware, or may be implemented by using software in combination with hardware.

According to a fifth aspect, another communication apparatus is described. The communication apparatus includes one or more processors coupled to a memory. The memory is configured to store a part or all of a necessary program or instructions for implementing a function in the first aspect. The one or more processors may execute the computer program or the instructions, and when the computer or the instructions is/are executed, the communication apparatus is enabled to implement the method in any possible design or implementation of the first aspect.

According to a sixth aspect, another communication apparatus is described. The communication apparatus includes one or more processors coupled to a memory. The memory is configured to store a part or all of a necessary program or instructions for implementing a function in the second aspect. The one or more processors may execute the computer program or the instructions, and when the computer or the instructions is/are executed, the communication apparatus is enabled to implement the method in any possible design or implementation of the second aspect.

In some embodiments of the fifth or the sixth aspect, the communication apparatus may further include the memory.

In some embodiments of the fifth or the sixth aspect, the communication apparatus may further include an interface circuit, and the processor is configured to communicate with another apparatus or component through the interface circuit.

In some embodiments, the communication apparatus may be a terminal, a module in a terminal, or a chip responsible for a communication function in a terminal, for example, a modem chip (also referred to as a baseband chip) or an SoC chip or a SIP chip that includes a modem module. In some embodiments, the communication apparatus may be a network device, for example, a base station (BS) or a component (for example, a circuit, a chip, or a chip system) in the BS.

According to a seventh aspect, a computer-readable storage medium is descried. The computer-readable storage medium stores computer-readable instructions, and when a computer reads and executes the computer-readable instructions, the computer is enabled to perform the method in any one of possible designs of the first aspect or the second aspect.

According to an eighth aspect, a computer program product is described. When a computer reads and executes the computer program product, the computer is enabled to perform the method in any one of possible designs of the first aspect or the second aspect.

According to a ninth aspect, this application provides a system comprising at least one of an apparatus in (or at) a terminal device of this application, or an apparatus in (or at) a network device of this application.

According to a tenth aspect, this application provides a method performed by a system comprising at least one of an apparatus in (or at) a terminal of this application, and an apparatus in (or at) a network device of this application.

This application encompasses various embodiments, including not only method embodiments, but also other embodiments such as apparatus embodiments and embodiments related to non-transitory computer readable storage media. Embodiments may incorporate, individually or in combinations, the features disclosed herein.

DESCRIPTION OF DRAWINGS

One or more embodiments are exemplarily described by corresponding accompanying drawings, and these exemplary illustrations and accompanying drawings constitute no limitation on the embodiments. Elements with the same reference numerals in the accompanying drawings are illustrated as similar elements, and the drawings are not limited to scale, in which:

FIG. 1 is a schematic diagram of an application scenario according to an embodiment of the present application.

FIG. 2 illustrates an example of a communication system.

FIG. 3 illustrates another example of an electronic device (ED) and a base station.

FIG. 4 illustrates a schematic diagram of units or modules in a device.

FIG. 5 illustrates an example apparatus 410 according to an implementation of the present application.

FIG. 6 is an example of a channel model of a MIMO system.

FIG. 7 shows an example of a process for a base station to obtain CSI.

FIG. 8 shows an example of an overall procedure for coding, modulation and layer mapping procedure.

FIG. 9 shows an example of joint CW to modulation and layer mapping with a same modulation scheme used for all layers.

FIG. 10 shows an example of joint CW to modulation and layer mapping with per layer modulation adaptation.

FIG. 11 shows an example of a subblock interleaving process with modulation adaptation.

FIG. 12 shows an example of a process for bit interleaving, modulation and layer mapping.

FIG. 13 shows an example of a basic signaling and transmission procedure for DL and UL transmission.

FIG. 14 is a schematic flow chart of a communication method 200 according to embodiment of the present application.

FIG. 15 shows an example of modulation and reliability ranking based on layer groups rather than single layer.

FIG. 16 shows an example of grouping two modulation bits that has the same priority in a same tier.

FIG. 17 is a schematic block diagram of a communication apparatus according to an embodiment of the present application.

FIG. 18 is a schematic block diagram of a communication apparatus according to an embodiment of the present application.

DESCRIPTION OF EMBODIMENTS

In order to understand features and technical contents of embodiments of the present application in detail, implementations of the embodiments of the present application will be described in detail below with reference to the accompanying drawings, and the attached drawings are only for reference and illustration purposes, and are not intended to limit the embodiments of the present applications. In the following technical descriptions, for ease of explanation, numerous details are set forth to provide a thorough understanding of the disclosed embodiments.

The technical solutions in embodiments of the present application may be applied to various communications systems, such as a fifth generation (5G) wireless communications system, a new ratio (NR) wireless communications system, a future communications system.

For ease of understanding the embodiments of the present application, a communications system shown in FIGS. 1～3 is taken as an example to describe in detail a communications system to which the embodiments of this application are applicable.

FIG. 1 is a schematic diagram of an application scenario according to an embodiment of the present application. Referring to FIG. 1, as an illustrative example without limitation, a simplified schematic illustration of a communication system is provided. The communication system 100 comprises a radio access network 120. The radio access network 120 may be a future radio access network, or a legacy (e.g. 5G or 4G, ) radio access network. One or more communication electronic devices (ED) 110a, 110b, 110c, 110d, 110e, 110f, 110g, 110h, 110i, 110j (generically referred to as 110) may be interconnected to one another or connected to one or more network nodes (170a, 170b, generically referred to as 170) in the radio access network 120. A core network 130 may be a part of the communication system and may be dependent or independent of the radio access technology used in the communication system 100. The communication system 100 also includes a public switched telephone network (PSTN) 140, the internet 150, and other networks 160.

FIG. 2 illustrates an example communication system 100. In general, the communication system 100 enables multiple wireless or wired elements to communicate data and other content. The purpose of the communication system 100 may be to provide content, such as voice, data, video, and/or text, via broadcast, multicast, groupcast, unicast, etc. The communication system 100 may operate by sharing resources, such as carrier spectrum bandwidth, between its constituent elements. The communication system 100 may include a terrestrial communication system and/or a non-terrestrial communication system. The communication system 100 may provide a wide range of communication services and applications (such as earth monitoring, remote sensing, passive sensing and positioning, navigation and tracking, autonomous delivery and mobility, etc. ) . The communication system 100 may provide a high degree of availability and robustness through a joint operation of a terrestrial communication system and a non-terrestrial communication system. For example, integrating a non-terrestrial communication system (or components thereof) into a terrestrial communication system can result in what may be considered a heterogeneous network comprising multiple layers. Compared to conventional communication networks, the heterogeneous network may achieve better overall performance through efficient multi-link joint operation, more flexible functionality sharing, and faster physical layer link switching between terrestrial networks and non-terrestrial networks.

The terrestrial communication system and the non-terrestrial communication system could be considered sub-systems of the communication system. In the example shown in FIG. 1, the communication system 100 includes electronic devices (ED) 110a, 110b, 110c, 110d (generically referred to as ED 110) , radio access networks (RANs) 120a, 120b, a non-terrestrial communication network 120c, a core network 130, a public switched telephone network (PSTN) 140, the Internet 150, and other networks 160. The RANs 120a, 120b include respective base stations (BSs) 170a, 170b, which may be generically referred to as terrestrial transmit and receive points (T-TRPs) 170a, 170b. The non-terrestrial communication network 120c includes an access node 172, which may be generically referred to as a non-terrestrial transmit and receive point (NT-TRP) 172.

Any ED 110 may be alternatively or additionally configured to interface, access, or communicate with any T-TRP 170a, 170b and NT-TRP 172, the Internet 150, the core network 130, the PSTN 140, the other networks 160, or any combination of the preceding. In some examples, ED 110a may communicate an uplink and/or downlink transmission over a terrestrial air interface 190a with T-TRP 170a. In some examples, the EDs 110a, 110b, 110c, and 110d may also communicate directly with one another via one or more sidelink air interfaces 190b. In some examples, ED 110d may communicate an uplink and/or downlink transmission over a non-terrestrial air interface 190c with NT-TRP 172.

The air interfaces 190a and 190b may use similar communication technology, such as any suitable radio access technology. For example, the communication system 100 may implement one or more channel access methods, such as code division multiple access (CDMA) , space division multiple access (SDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal FDMA (OFDMA) , or single-carrier FDMA (SC-FDMA, also known as discrete Fourier transform spread OFDMA, DFT-s-OFDMA) in the air interfaces 190a and 190b. The air interfaces 190a and 190b may utilize other higher dimension signal spaces, which may involve a combination of orthogonal and/or non-orthogonal dimensions.

The non-terrestrial air interface 190c can enable communication between the ED 110d and one or multiple NT-TRPs 172 via a wireless link or simply a link. For some examples, the link is a dedicated connection for unicast transmission, a connection for broadcast transmission, or a connection between a group of EDs 110 and one or multiple NT-TRPs 172 for multicast transmission.

The RANs 120a and 120b are in communication with the core network 130 to provide the EDs 110a 110b, and 110c with various services such as voice, data, and other services. The RANs 120a and 120b and/or the core network 130 may be in direct or indirect communication with one or more other RANs (not shown) , which may or may not be directly served by core network 130, and may or may not employ the same radio access technology as RAN 120a, RAN 120b or both. The core network 130 may also serve as a gateway access between (i) the RANs 120a and 120b or EDs 110a 110b, and 110c or both, and (ii) other networks (such as the PSTN 140, the Internet 150, and the other networks 160) . In addition, some or all of the EDs 110a 110b, and 110c may include functionality for communicating with different wireless networks over different wireless links using different wireless technologies and/or protocols. Instead of wireless communication (or in addition thereto) , the EDs 110a 110b, and 110c may communicate via wired communication channels to a service provider or switch (not shown) , and to the Internet 150. PSTN 140 may include circuit switched telephone networks for providing plain old telephone service (POTS) . Internet 150 may include a network of computers and subnets (intranets) or both, and incorporate protocols, such as Internet Protocol (IP) , Transmission Control Protocol (TCP) , User Datagram Protocol (UDP) . EDs 110a 110b, and 110c may be multimode devices capable of operation according to multiple radio access technologies, and incorporate multiple transceivers necessary to support such.

Furthermore, communication between different devices/apparatuses in various implementations of this disclosure may refer to direct communication (that is, without the need of forwarding by another device/apparatus) , or may refer to communication (s) between different devices/apparatuses via another device/apparatus (that is, requiring forwarding by another device/apparatus) . Alternatively, such communication (s) may involve one functional unit inside a device/apparatus using another functional unit within the device/apparatus to communicate with another device/apparatus. In other words, phrases such as “sending (or transmitting) information to... (an ED or a base station) ” in this disclosure may be understood as a destination endpoint of the information being an ED or a base station, including, sending/transmitting information directly or indirectly to an ED or a base station. Similarly, phrases like “receiving information from... (an ED or a base station) ” may be understood as a source endpoint of the information being an ED or a base station, including directly or indirectly receiving information from an ED or a base station. Between the source endpoint that sends the information and the destination endpoint, necessary processing such as, but not limited to, format conversion, digital-to-analog conversion, amplification, and filtering may be performed on the information. However, the destination endpoint may understand valid information from the source endpoint. A similar understanding applies to other descriptions in this disclosure without reiterating details already described. In the present disclosure, the terms "send" and "transmit" may be used interchangeably in different implementations of this disclosure.

FIG. 3 illustrates another example of an ED 110 and a base station 170a, 170b and/or 170c. The ED 110 is used to connect persons, objects, machines, etc. The ED 110 may be widely used in various scenarios including, for example, cellular communications, device-to-device (D2D) , vehicle to everything (V2X) , peer-to-peer (P2P) , machine-to-machine (M2M) , machine-type communications (MTC) , internet of things (IoT) , virtual reality (VR) , augmented reality (AR) , mixed reality (MR) , metaverse, digital twin, industrial control, self-driving, remote medical, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, drones, robots, remote sensing, passive sensing, positioning, navigation and tracking, autonomous delivery and mobility, etc.

Each ED 110 represents any suitable end user device for wireless operation and may include such devices (or may be referred to) as a user equipment/device (UE) , a wireless transmit/receive unit (WTRU) , a mobile station, a fixed or mobile subscriber unit, a cellular telephone, a station (STA) , a machine type communication (MTC) device, a personal digital assistant (PDA) , a smartphone, a laptop, a computer, a tablet, a wireless sensor, a consumer electronics device, a smart book, a vehicle, a car, a truck, a bus, a train, or an IoT device, wearable devices (such as a watch, a pair of glasses, head mounted equipment, etc. ) , an industrial device, or an apparatus in (e.g. communication module, modem, or chip) or comprising the forgoing devices, among other possibilities. Future generation EDs 110 may be referred to using other terms. The base station 170a and 170b is a T-TRP and will hereafter be referred to as T-TRP 170. Also shown in FIG. 3, a NT-TRP will hereafter be referred to as NT-TRP 172. Each ED 110 connected to T-TRP 170 and/or NT-TRP 172 can be dynamically or semi-statically turned-on (i.e., established, activated, or enabled) , turned-off (i.e., released, deactivated, or disabled) and/or configured in response to one of more of: connection availability and connection necessity.

The ED 110 includes a transmitter 201 and a receiver 203 coupled to one or more antennas 204. Only one antenna 204 is illustrated to avoid congestion in the drawing. One, some, or all of the antennas 204 may alternatively be panels. The transmitter 201 and the receiver 203 may be integrated, e.g. as a transceiver. The transceiver is configured to modulate data or other content for transmission by at least one antenna 204 or network interface controller (NIC) . The transceiver is also configured to demodulate data or other content received by the at least one antenna 204. Each transceiver includes any suitable structure for generating signals for wireless or wired transmission and/or processing signals received wirelessly or by wire. Each antenna 204 includes any suitable structure for transmitting and/or receiving wireless or wired signals.

The ED 110 includes at least one memory 208. The memory 208 stores instructions and data used, generated, or collected by the ED 110. For example, the memory 208 could store software instructions or modules configured to implement some or all of the functionality and/or embodiments described herein and that are executed by one or more processing unit (s) (e.g., a processor 210) . Each memory 208 includes any suitable volatile and/or non-volatile storage and retrieval device (s) . Any suitable type of memory may be used, such as random access memory (RAM) , read only memory (ROM) , hard disk, optical disc, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, on-processor cache, and the like.

The ED 110 may further include one or more input/output devices (not shown) or interfaces (such as a wired interface to the Internet 150 in FIG. 1) . The input/output devices or interfaces permit interaction with a user or other devices in the network. Each input/output device or interface includes any suitable structure for providing information to or receiving information from a user, and/or for network interface communications. Suitable structures include, for example, a speaker, microphone, keypad, keyboard, display, touch screen, etc.

The ED 110 includes the processor 210 for performing operations including those operations related to preparing a transmission for uplink transmission to the NT-TRP 172 and/or the T-TRP 170; those operations related to processing downlink transmissions received from the NT-TRP 172 and/or the T-TRP 170; and those operations related to processing sidelink transmission to and from another ED 110. Processing operations related to preparing a transmission for uplink transmission may include operations such as encoding, modulating, transmit beamforming, and generating symbols for transmission. Processing operations related to processing downlink transmissions may include operations such as receive beamforming, demodulating and decoding received symbols. Depending upon the embodiment, a downlink transmission may be received by the receiver 203, possibly using receive beamforming, and the processor 210 may extract signaling from the downlink transmission (e.g. by detecting and/or decoding the signaling) . An example of signaling may be a reference signal transmitted by the NT-TRP 172 and/or by the T-TRP 170. In some embodiments, the processor 210 implements the transmit beamforming and/or the receive beamforming based on the indication of beam direction, e.g. beam angle information (BAI) , received from the T-TRP 170. In some embodiments, the processor 210 may perform operations relating to network access (e.g. initial access) and/or downlink synchronization, such as operations relating to detecting a synchronization sequence, decoding and obtaining the system information, etc. In some embodiments, the processor 210 may perform channel estimation, e.g. using a reference signal received from the NT-TRP 172 and/or from the T-TRP 170.

Although not illustrated, the processor 210 may form part of the transmitter 201 and/or part of the receiver 203. Although not illustrated, the memory 208 may form part of the processor 210.

The processor 210, the processing components of the transmitter 201, and the processing components of the receiver 203 may each be implemented by the same or different one or more processors that are configured to execute instructions stored in a memory (e.g. in the memory 208) . Alternatively, some or all of the processor 210, the processing components of the transmitter 201, and the processing components of the receiver 203 may each be implemented using dedicated circuitry, such as a programmed field-programmable gate array (FPGA) , an application-specific integrated circuit (ASIC) , or a hardware accelerator such as a graphics processing unit (GPU) or an artificial intelligence (AI) accelerator.

The T-TRP 170 may be known by other names in some implementations, such as a base station, a base transceiver station (BTS) , a radio base station, a network node, a network device, a device on the network side, a transmit/receive node, a Node B, an evolved NodeB (eNodeB or eNB) , a Home eNodeB, a next Generation NodeB (gNB) , a transmission point (TP) , a site controller, an access point (AP) , a wireless router, a relay station, a terrestrial node, a terrestrial network device, a terrestrial base station, a base band unit (BBU) , a remote radio unit (RRU) , an active antenna unit (AAU) , a remote radio head (RRH) , a central unit (CU) , a distributed unit (DU) , a positioning node, among other possibilities. The T-TRP 170 may be a macro BS, a pico BS, a relay node, a donor node, or the like, or combinations thereof. The T-TRP 170 may refer to the forgoing devices or refer to apparatus (e.g. a communication module, a modem, or a chip) in the forgoing devices.

In some embodiments, the parts of the T-TRP 170 may be distributed. For example, some of the modules of the T-TRP 170 may be located remote from the equipment that houses the antennas 256 for the T-TRP 170, and may be coupled to the equipment that houses the antennas 256 over a communication link (not shown) sometimes known as front haul, such as common public radio interface (CPRI) . Therefore, in some embodiments, the term T-TRP 170 may also refer to modules on the network side that perform processing operations, such as determining the location of the ED 110, resource allocation (scheduling) , message generation, and encoding/decoding, and that are not necessarily part of the equipment that houses the antennas 256 of the T-TRP 170. The modules may also be coupled to other T-TRPs. In some embodiments, the T-TRP 170 may actually be a plurality of T-TRPs that are operating together to serve the ED 110, e.g. through the use of coordinated multipoint transmissions.

The T-TRP 170 includes at least one transmitter 252 and at least one receiver 254 coupled to one or more antennas 256. Only one antenna 256 is illustrated to avoid congestion in the drawing. One, some, or all of the antennas 256 may alternatively be panels. The transmitter 252 and the receiver 254 may be integrated as a transceiver. The T-TRP 170 further includes a processor 260 for performing operations including those related to: preparing a transmission for downlink transmission to the ED 110, processing an uplink transmission received from the ED 110, preparing a transmission for backhaul transmission to the NT-TRP 172, and processing a transmission received over backhaul from the NT-TRP 172. Processing operations related to preparing a transmission for downlink or backhaul transmission may include operations such as encoding, modulating, precoding (e.g. multiple input multiple output (MIMO) precoding) , transmit beamforming, and generating symbols for transmission. Processing operations related to processing received transmissions in the uplink or over backhaul may include operations such as receive beamforming, demodulating received symbols, and decoding received symbols. The processor 260 may also perform operations relating to network access (e.g. initial access) and/or downlink synchronization, such as generating the content of synchronization signal blocks (SSBs) , generating the system information, etc. In some embodiments, the processor 260 also generates an indication of beam direction, e.g. BAI, which may be scheduled for transmission by a scheduler 253. The processor 260 performs other network-side processing operations described herein, such as determining the location of the ED 110, determining where to deploy the NT-TRP 172, etc. In some embodiments, the processor 260 may generate signaling, e.g. to configure one or more parameters of the ED 110 and/or one or more parameters of the NT-TRP 172. Any signaling generated by the processor 260 is sent by the transmitter 252. Note that “signaling” , as used herein, may alternatively be called control signaling. Signaling may be transmitted in a physical layer control channel, e.g. a physical downlink control channel (PDCCH) , in which case the signaling may be known as dynamic signaling. Signaling transmitted in a downlink physical layer control channel may be known as Downlink Control Information (DCI) . Siganling transmitted in an uplink physical layer control channel may be known as Uplink Control Information (UCI) . Signaling transmitted in a sidelink physical layer control channel may be known as Sidelink Control Information (SCI) . Signaling may be included in a higher-layer (e.g., higher than physical layer) packet transmitted in a physical layer data channel, e.g. in a physical downlink shared channel (PDSCH) , in which case the signaling may be known as higher-layer signaling, static signaling, or semi-static signaling. Higher-layer signaling may also refer to Radio Resource Control (RRC) protocol signaling or Media Access Control –Control Element (MAC-CE) signaling.

The scheduler 253 may be coupled to the processor 260. The scheduler 253 may be included within or operated separately from the T-TRP 170. The scheduler 253 may schedule uplink, downlink, sidelink, and/or backhaul transmissions, including issuing scheduling grants and/or configuring scheduling-free (e.g., “configured grant” ) resources. The T-TRP 170 further includes a memory 258 for storing information and data. The memory 258 stores instructions and data used, generated, or collected by the T-TRP 170. For example, the memory 258 could store software instructions or modules configured to implement some or all of the functionality and/or embodiments described herein and that are executed by the processor 260.

Although not illustrated, the processor 260 may form part of the transmitter 252 and/or part of the receiver 254. Also, although not illustrated, the processor 260 may implement the scheduler 253. Although not illustrated, the memory 258 may form part of the processor 260.

The processor 260, the scheduler 253, the processing components of the transmitter 252, and the processing components of the receiver 254 may each be implemented by the same or different one or more processors that are configured to execute instructions stored in a memory, e.g. in the memory 258. Alternatively, some or all of the processor 260, the scheduler 253, the processing components of the transmitter 252, and the processing components of the receiver 254 may be implemented using dedicated circuitry, such as a programmed FPGA, a hardware accelerator (e.g., a GPU or AI accelerator) , or an ASIC.

Although the NT-TRP 172 is illustrated as a drone only as an example, the NT-TRP 172 may be implemented in any suitable non-terrestrial form, such as satellites and high altitude platforms, including international mobile telecommunication base stations and unmanned aerial vehicles, for example. Also, the NT-TRP 172 may be known by other names in some implementations, such as a non-terrestrial node, a non-terrestrial network device, or a non-terrestrial base station. The NT-TRP 172 includes a transmitter 272 and a receiver 274 coupled to one or more antennas 280. Only one antenna 280 is illustrated to avoid congestion in the drawing. One, some, or all of the antennas may alternatively be panels. The transmitter 272 and the receiver 274 may be integrated as a transceiver. The NT-TRP 172 further includes a processor 276 for performing operations including those related to: preparing a transmission for downlink transmission to the ED 110, processing an uplink transmission received from the ED 110, preparing a transmission for backhaul transmission to T-TRP 170, and processing a transmission received over backhaul from the T-TRP 170. Processing operations related to preparing a transmission for downlink or backhaul transmission may include operations such as encoding, modulating, precoding (e.g. MIMO precoding) , transmit beamforming, and generating symbols for transmission. Processing operations related to processing received transmissions in the uplink or over backhaul may include operations such as receive beamforming, demodulating received symbols, and decoding received symbols. In some embodiments, the processor 276 implements the transmit beamforming and/or receive beamforming based on beam direction information (e.g. BAI) received from the T-TRP 170. In some embodiments, the processor 276 may generate signaling, e.g. to configure one or more parameters of the ED 110. In some embodiments, the NT-TRP 172 implements physical layer processing, but does not implement higher layer functions such as functions at the medium access control (MAC) or radio link control (RLC) layer. As this is only an example, more generally, the NT-TRP 172 may implement higher layer functions in addition to physical layer processing.

The NT-TRP 172 further includes a memory 278 for storing information and data. Although not illustrated, the processor 276 may form part of the transmitter 272 and/or part of the receiver 274. Although not illustrated, the memory 278 may form part of the processor 276.

The processor 276, the processing components of the transmitter 272, and the processing components of the receiver 274 may each be implemented by the same or different one or more processors that are configured to execute instructions stored in a memory, e.g. in the memory 278. Alternatively, some or all of the processor 276, the processing components of the transmitter 272, and the processing components of the receiver 274 may be implemented using dedicated circuitry, such as a programmed FPGA, a hardware accelerator (e.g., a GPU or AI accelerator) , or an ASIC. In some embodiments, the NT-TRP 172 may actually be a plurality of NT-TRPs that are operating together to serve the ED 110, e.g. through coordinated multipoint transmissions.

The T-TRP 170, the NT-TRP 172, and/or the ED 110 may include other components, but these have been omitted for the sake of clarity.

FIG. 4 illustrates a schematic diagram of units or modules in a device, such as in the ED 110, in the T-TRP 170, or in the NT-TRP 172. One or more steps of the embodiment methods provided herein may be performed by corresponding units or modules, according to FIG. 4. For example, a signal may be transmitted by a transmitting unit or by a transmitting module. A signal may be received by a receiving unit or by a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by an artificial intelligence (AI) or machine learning (ML) module. The respective units or modules may be implemented using hardware, one or more components or devices that execute software, or a combination thereof. For instance, one or more of the units or modules may be a circuit such as an integrated circuit. Examples of an integrated circuit includes a programmed FPGA, a GPU, or an ASIC. For instance, one or more of the units or modules may be logical such as a logical function performed by a circuit, by a portion of an integrated circuit, or by software instructions executed by a processor. It will be appreciated that where the modules are implemented using software for execution by a processor for example, the modules may be retrieved by a processor, in whole or part as needed, individually or together for processing, in single or multiple instances, and that the modules themselves may include instructions for further deployment and instantiation.

Additional details regarding the EDs 110, the T-TRP 170, and the NT-TRP 172 are known to those of skill in the art. As such, these details are omitted here.

Channel coding is an indispensable module in communications systems that encode K source bits into N code bits to provide error correction capability against adversary channel condition such as noise and interference. The code rate is R=K/N. In practice, the code rate R is selected according to channel quality.

Polar codes are capacity-achieving codes and thus a great breakthrough in coding theory. As code length approaches infinity, the synthesized channels (or subchannels) become either noiseless or pure noise. The noiseless subchannels are utilized to transport information, and their proportion is proven to achieve the channel capacity defined by Shannon. The above-mentioned channel polarization phenomenon occurs under successive cancellation (SC) or SC-based decoding, which has a relatively low complexity.

Low-density parity-check (LDPC) codes are capacity-approaching codes. LDPC codes are usually defined by a parity-check matrix, which has far more zeros than ones, thus having low density. By properly designing the positions of ones in the matrix, the decoding performance can be improved. Although LDPC codes can be viewed as a type of random codes, introducing structures can facilitate its hardware implementations of both encoder and decoder. Quasi-cyclic is such a structure that first defines a smaller base matrix or base graph (BG) , and then perform “lifting” by replacing its ones with a cyclic shifted version of identity matrix.

Rate matching is performed after channel encoding, by either puncturing/shortening or repeating some code bits. The purpose is to obtain a code bit sequence of desired length for transmission over limited channel resources.

Channel interleaver is applied after channel encoding and rate matching by permuting the code bits. The purpose is to provide stable or superior performance under high-order modulation or in fading channel.

Hybrid automatic repeat request (HARQ) is a mechanism to provide reliable wireless transmission. It combines forward error correction (FEC) and automatic repeat request (ARQ) . In HARQ, the initial transmission is a FEC code word with CRC bits to support error detection at the receiver. If a decoding error is detected, the receiver will send back a NACK signaling to inform the transmitter of the error, and request for a retransmission. The retransmitted bits can be directly selected from the initially transmitted bits, or incrementally generated code bits which form a longer code word with the initially transmitted bits. The former is called chase-combining HARQ (CC-HARQ) and the latter is called incremental-redundancy HARQ (IR-HARQ) . Typically, IR-HARQ outperforms CC-HARQ with the additional coding gain from incremental redundancy.

Low Density Parity Check (LDPC) code is a channel coding scheme very close to Shannon line, and features good performance and low complexity. Currently, LDPC has been adopted as data channel coding schemes by 3GPP 5G New Radio (NR) and IEEE 802.11 systems.

The LDPC code is encoded by through a parity-check matrix. A widely-adopted LDPC code has a QC structure, and a shifting value of each block is designed to avoid a bad structure such as a short circle, and improve a code distance. At present, the main decoding algorithms for LDPC codes are Min-Sum (MS) and Belief Propagation (BP) . In terms of decoding performance, the BP decoding algorithm is better, but it has a large amount of information storage and a complex computation overhead, which is not convenient to hardware implementation. Therefore, Offset-MS and Normalized-MS decoding algorithms are used in realistic communication systems. The LDPC codes implemented in practice is to extend the “1” in the basic graph (BG) by a square matrix, which is a cyclic shifted version of an identity matrix. The BG of QC-LDPC code can be defined by BG= (X, Y, F) , where X corresponds to a variable, Y corresponds to a check equation, and F is its edge connections. The Tanner graph is obtained after QC lifting with an expansion factor Zc. That is, a bipartite graph G= (V, C, E) , where V is a variable node, C is a check node, E is a connected edge, and a corresponding parity matrix column quantity N=|V|=Zc |X|. The quantity of rows of the check matrix M=|C|=Zc |Y|, and a quantity of non-zero elements of the check matrix is |E|=Z|F|.

5G data channels support information block length ranging from 1 to 8448. The standard describes two parity-check matrices: BG1 and BG2. The same base graph, lifted by different lifting sizes, can adapt to a wide set of different code rates and lengths. To achieve this, one only needs to store the Lifting Size and Shifting Value lists in the look-up tables, and rate matching and IR-HARQ based on the tables.

In NR LDPC codes, a codeword before rate matching (referred as a mother codeword) typically consists of three disjoint portions or parts, i.e., systematic bits, core parity check bits and extended parity check bits. In NR LDPC code, four different redundancy versions (RVs) including RV0, RV1, RV2 and RV3 are generated after rate matching. In initial transmission, RV0 is normally selected in which most of the systematic bits are included in the set of coded bits. Meanwhile, depending on the effective code rate, part of core parity bits or all core parity check bits and extended parity bits are included in RV0. As a result, RV0 has the highest self-decodable ability among all RVs (i.e., RV0 can be self-decodable at highest code rate) . In retransmission, the transmitter may select RV1, RV2 or RV3. Nevertheless, only RV3 is self-decodable, while RV1 and RV2 are not self-decodable at high code rate. The main reason is that, at some code rates, RV1 and RV2 may only consist of parity check bits, resulting in unsuccessfully decoding at the receiver.

Multiple input multiple-output technology (sometimes simply referred to as “MIMO” ) allows an antenna array having multiple antennas to perform enhanced signal transmissions and receptions, which can result in higher data transmission rates. The above ED 110 and T-TRP 170, and/or NT-TRP may use MIMO to communicate over physical layer wireless resources. MIMO utilizes multiple antennas at a transmit apparatus and/or receive apparatus to transmit and/or receive data in a same physical layer resource block over multiple parallel wireless signals. MIMO may involve beamforming parallel wireless signals for reliable multipath transmission of data in the resource block. MIMO may involve bonding parallel wireless signals that transport different data, effectively increasing the data rate of the data carried in a resource block.

In recent years, a MIMO wireless communication system with the above T-TRP 170 and/or NT-TRP 172 configured with a large number of antennas (known as a large-scale MIMO or massive MIMO, for example) has gained wide attention from academia and industry. In the large-scale MIMO system, the T-TRP 170 and/or NT-TRP 172 are generally configured with more than ten antennas (such as 128 or 256 antennas) , and serve dozens of the ED 110 (such as 40 devices) . By having a large number of antennas, the T-TRP 170 and/or NT-TRP 172 can increase the degree of spatial freedom of wireless communications, improve data transmission rate, spectrum efficiency and power efficiency, and minimize or largely eliminate the interference between cells. Using the degree of spatial freedom provided by the large number of antennas, the T-TRP 170 and/or NT-TRP 172 of each cell can communicate with many ED 110 in the cell on a same frequency resource at a same time (that is, on a same time-frequency resource) , thus greatly increasing the spectrum efficiency of the system. By having a large number of antennas, the T-TRP 170 and/or NT-TRP 172 also enable each user to have better spatial directivity for uplink and downlink transmission. This can further result in a reduction of transmission power at one or more of the T-TRP 170, the NT-TRP 172, and the ED 110, thus improving overall power efficiency in the system.

FIG. 5 illustrates an example apparatus 410 according to an implementation of the present application. The apparatus 410 may be a communication device or an apparatus implemented in a communication device such as the ED 110 or the TRPs 170a, 170b, 172. For example, the apparatus 410 implemented in an ED may be an integrated circuit, which in some instances may be referred to as a chip, a modem, a modem chip, a baseband chip, or a baseband processor. In some implementations, one or more integrated circuits can be packaged into a system-on-chip, a system-in-package, or a multi-chip module. The apparatus 410 can include one or more integrated circuits and other discrete components. In some implementations, the apparatus 410 may be a module within the ED 110, or within the apparatus 310. In some implementations, the apparatus 410 may be a module within one of the TRPs 170a, 170b, 172, or the apparatus 320.

In an example, the apparatus 410 may include one or more processors 411, and an interface circuit 412. The apparatus 410 may further include a memory 413. The one or more processors 411 are configured to process signals and execute one or more communication protocols. The memory 413 is configured to store at least a part of corresponding computer program instructions and/or data. In an example, the one or more processors 411 execute the computer program instructions stored in the memory 413 to implement related operations (for example, inputting, outputting, receiving, and transmitting) in the method embodiments disclosed herein. In some implementations, the memory 413 being configured to store the corresponding computer program instructions and/or data may mean that the memory 413 is configured to store all of the corresponding computer program instructions and/or data for execution by the one or more processors 411. In some implementations, the memory 413 being configured to store the corresponding computer program instructions and/or data may mean that the memory 413 is configured to store a part of the corresponding computer program instructions and/or data. For example, the part of the corresponding computer program instructions and/or data may include computer program instructions and/or data that need to be currently executed by the one or more processors 411. Thus, the memory 413 may store different parts of computer program instructions and/or data for a plurality times for the one or more processors 411 to perform related operations in the method embodiments disclosed herein. As a communication interface, the interface circuit 412 is configured to implement communication with another component. For example, the interface circuit 412 may communicate a signal with another apparatus or system, such as a radio frequency processing apparatus or another processor. The signal may include or carry information intended as a payload, such as user data, control information, etc. The signal may also include or carry information useful to a receiver, but not necessarily as a payload, such as a pilot signal or reference signal. Communicating the signal may include transmitting the signal to another component or device. Communicating the signal may additionally or alternatively include receiving the signal from another component or device. Transmitting the signal may include outputting the signal to a component or device that is directly or indirectly coupled to the interface circuit 412. Receiving the signal may include inputting or obtaining the signal from a component or device that is directly or indirectly couped to the interface circuit 412. Optionally, to reduce a load of the one or more processors, a baseband signal processing circuit 414 may be also disposed to implement processing of at least a part of baseband signals, including signal demodulation, modulation, encoding, decoding, or the like.

The apparatus 410 may be the processor 210 (or 260) within the apparatus 310 (or 320) , in some scenarios, or may be included within the processor 210 (or 260) within the apparatus 310 (or 320) in some scenarios. The apparatus 410 may be a baseband chip or may include a baseband chip. In some implementations, the apparatus 410 may be independently packaged into a chip. In some implementations, the apparatus 310 (or 320) includes different types of chips. The apparatus 410 may be packaged into a processor chip (for example, an SoC chip or a SIP chip) with the different types of chips. In some implementations, the apparatus 410 may be packaged into a chip with some or all of circuits of a radio frequency processing system that may further be included in the apparatus 310 (or 320) .

MIMO technology may include single-user MIMO (SU-MIMO) , where signals on multiple spatial layers are transmitted to a same ED, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple EDs.

1) Apparatus System Description

A MIMO system may include a receive apparatus (ED 110 for a downlink transmission, T-TRP 170 or NT-TRP 172 for an uplink transmission, for example) connected to one or more receive (RX) antennas, a transmit apparatus (T-TRP 170 or NT-TRP 172 for a downlink transmission, or ED 110 for an uplink transmission, for example) connected to one or more transmit (TX) antennas. For instance, a plurality of RX antennas may form an antenna array in which the plurality of RX antennas are arranged in line at even intervals, which may be known as a uniform linear array (ULA) .

FIG. 6 is an example of a channel model of a MIMO system. A transmit apparatus is connected to four TX antennas, x1 to x4, a receive apparatus is connected to four RX antennas, y1 to y4, and a transmission channel may be formed between each TX antenna and each RX antenna pair. For example, a signal transmitted through x1 may be received by y2 through channel h21. A signal transmitted through x3 may be received by y1 through channel h13.

Antenna port, which may also be referred to as port for short, is a transmit antenna identified by a receiving apparatus, or a transmit antenna that can be distinguished in spatial domain. For each virtual antenna, one antenna port may be configured, and each virtual antenna may be a weighted combination of multiple physical antennas. Each antenna port may correspond to one reference signal port.

2) Reference signal and channel estimation

In a MIMO system, to implement functions such as system synchronization, channel information feedback, and data transmission, channel estimation needs to be performed on an uplink channel or a downlink channel. Channel estimation refers to the process of reconstructing or restoring received signals to compensate for signal distortion caused by channel fading and noise. In channel estimation, a reference signal sent by a transmitting apparatus may be used to track a change in the time domain and/or frequency domain of a channel, so as to reconstruct or restore a received signal. The reference signal may also be referred to as a pilot signal, a reference sequence or the like, and is described as a reference signal in the following for ease of understanding. The reference signal comprises, for example, a channel state information-reference signal (CSI-RS) , a sounding reference signal (SRS) , and a demodulation reference signal (DMRS) .

The CSI-RS is mainly used for downlink channel estimation corresponding to a physical antenna port. For example, a receiving apparatus (i.e. a UE) may perform channel estimation on each physical antenna port based on a CSI-RS sent by a transmitting apparatus (i.e. a base station) , to feedback channel state information (CSI) based on a channel estimation result. The CSI may include related information such as a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a layer indicator (LI) , and a rank indicator (RI) . The CSI is used to reconstruct or precode the downlink channel.

FIG. 7 illustrates a process for a base station to obtain CSI. Referring to FIG. 7, in some implementations, a process in which the base station obtains CSI may include: sending, by the base station, a reference signal to the UE; obtaining, by the UE, an estimated CSI value according to the received reference signal, selecting, by the UE, a precoding vector from a codebook according to the estimated CSI value, and feedback, by the UE, the index of the precoding vector to the base station; the base station determines a CSI reconstruction value with reference to the index of the precoding vector. The CSI reconstruction value can be a CSI closest to the true value of the CSI that can be obtained by the base station.

Multiple antenna at the transmitter and/or receiver side has been well used for wireless communications system to either improve the reliability or throughput. The communication scheme is usually known as multiple input multiple output (MIMO) communications. Multiple antennas at the transmitter and/or receiver side can be used to obtain diversity gain against fading channel or can be used to enable spatial multiplexing, that is, to transmit multiple data streams over multiple layers in parallel at the same time frequency resource to increase throughput.

When a spatial multiplexing scheme is used, transmissions may be over multiple transmission layers. A transmission layer (which may be simplified as a layer) refers to a data stream that is transmitted. In the case of MIMO transmissions, there are at least two transmission layers, or more generally L transmission layers (where L is at least two) . The L transmission layers are mapped to N antennas or N antenna ports (which are fed to respective transmission antennas (or antenna ports) ) by means of a MIMO precoder matrix of size N x L. Generally, the number of transmission layers (i.e., L, also referred to as the transmission rank or, simply, the rank) is less than or equal to the number of antennas (i.e., N) . In the present disclosure, there are at least two transmission layers for MIMO transmission, and the transmission layers may be referred to as MIMO layers.

In 5G new radio (NR) , up to 8 MIMO layer in a single transmission is supported. For MIMO transmission in cellular system, the transmitter may first encode an information data block into a codeword (CW) , the CW is then modulated and mapped to multiple MIMO layers before precoding, this process is usually known as CW-to-layer mappings. In NR, up to two CWs in a single transmission, with each CW mapped to a max of 4 layers, with a total of up to 8 layers per single user transmission, are supported.

In 6G and future wireless communications, terabits MIMO (T-MIMO) or massive MIMO (m-MIMO) may have transmitter and/or receiver equipped with large number of antennas and support transmission over a large number of layers. The channel quality among different layers may significantly varies.

One potential solution to CW-to-layer mapping schemes is to use One CW map to each transmission layer. This allows maximizing throughput when accurate link adaptation is available. However, the scheme may incur significant overhead to the system, and can be impractical especially with large number of layers. The overhead may include: HARQ feedback overhead, HARQ process management overhead, signaling overhead, CSI feedback overhead. In addition, CB length can be very different for different layers, which may impact performance for some short-length CB, and also makes segmentation more complicated.

This application aims to provide an efficient, robust and low overhead solution for CW-to-layer mapping for MIMO communications that has a significant number of layers.

Therefore, in this application, a solution that use one CW map to a number of layers is proposed. Those layers may have varying channel quality. The scheme considers a joint CW to QAM and layer mapping solution. The basic idea is to map the more important bits of the codeword from the encoding process to higher reliability bits based on both bit location of modulation symbol and layer index. This way, the more important coded bits are better protected, which yields better decoding performance.

For better performance of this scheme, a ranking of the reliability (or the experienced channel quality) of the combination of layer index and modulation symbol is needed. In order for the BS and user to understand in the same way about the ranking results as well as understand how the joint CW to QAM and layer mapping is done, BS may need to indicate information regarding the ranking and/or parameters used for the joint mapping scheme. This disclosure proposes different method and signaling to indicate ranking and other parameters for joint CW to QAM and layer mapping process.

FIG. 8 illustrates an example of an overall procedure for coding, modulation and layer mapping process. Referring FIG. 8, the transport block (TB) information may be segmented into multiple code blocks before encoding, each code block is encoded and rate matched separately. And coded bits after rate matching may be concatenated into a single code bit stream as a codeword. The CB segmentation and concatenation process are not needed if there is a single CB. In addition, if there are multiple CBs, alternatively, each CB may be modulated and mapped to layers separately. CRC may be optionally appended into the TB as well as each CB, which is not shown in the figure. The output coded bit stream, or the codeword (CW) , may be optionally scrambled first. The CW is then modulated and mapped to one or multiple transmission layers. The complex value vector after modulation and layer mapping is then precoded by multiple antenna precoding process, then it is going through resource mapping and transmitted through multiple physical antennas. The rate matching process may include bit selection, subblock interleaving and bit interleaving as described in more details in this disclosure. The process can be applicable to uplink or downlink data transmissions. In some scenarios, e.g. in uplink, there may be transform precoding or DFT based precoding process for transmission using DFT-OFDM that is not shown in the figure.

The general process of the joint CW to modulation and layer mapping is as follows:

Step 0: Bit selection. The information bits are first encoded using a FEC code, such as LDPC code. The output coded bits are selected based on redundancy version and number of coded bits required to obtain a coded bit stream. This process is usually called rate matching. In the rate matching process, bit selection may be first performed to select the coded bits according to the redundancy version. The bit selection process usually obtained by first write encoded bits using mother code into a circular buffer, then the initial location of the coded bits may be determined from the redundancy version.

Step 1 (optional) : Coded bit priority ranking: arrange the coded bits according to the priority/importance of the coded bits.

Step 2: Define joint modulation bits and MIMO layer reliability tiers (For example, if there is m_l bits for the modulation level with the same modulation scheme for all L layers, there are total ofreliability tiers) , L is the number of the transmission layers mapped to one codeword. The reliability tier also be referred to a tier for simplification in following embodiments.

Optionally, we may group bits from modulation symbols with same reliability in the same tier. In some scenario, multiple layers may be grouped in the same layer group and belong to the same reliability tier.

The tier may be regarded as a function of a transmission layer (which may be represented with a transmission layer index) , or more generally a combination of a transmission layer and a bit location of a modulation symbol (which may be represented with a combination of a transmission layer index and a bit location index) . Similarly, the tier also can be represented with an index. For example, if the tier is a function of a transmission layer index, a tier index has a one-to-one mapping relationship to the transmission layer index. For another example, if the tier is a function of a combination of a transmission layer index and a bit location index, a tier index has one-to-one mapping relationship with the combination of the transmission layer index and the bit location index. Optionally, the above layer index also can be layer group index, the bit location index also can be a bit location group index. Therefore, the tier also can be a function of a layer group index, or a function of a combination of a layer index/layer group index and a bit location index/bit location group index. A coded bit sequence that needs to be modulated and mapped to L transmission layers can be divided into several sub-sequences or subblocks, and each sub-sequence or each subblock may corresponds to one tier. The coded bit sequence can be mapped to modulation symbols and the L transmission layers based on a corresponding relationship between the sub-sequence/subblock and the tier.

Step 3: Order (also referred as “rank” ) the reliability tiers based on bit reliability from both MIMO layers (that is, the transmission layers) and modulation bits. The disclosure provides more details on how to obtain an ordering (also referred as “a ranking” ) , which also can be called a reliability ranking. Since the ranking is obtained based on both the transmission layer and the modulation bit, the ranking also can be called a ranking of a combination of a transmission layer and a bit location of a modulation symbol.

Step 4: Map the priority ordered coded bit sequence (that is, the ranked coded bit sequence) to the corresponding modulation symbols and transmission layers based on the reliability ranking.

This may consist of a few steps:

1. Map the original bit sequence into different combinations of transmission layers and bit locations of modulation symbols based on the reliability ranking. This mapping is done such that the earlier bits (thus more important bits) that have lower indexes in the ranked coded bit sequence are mapped to the higher reliability combination of the bit location and the transmission layer.

2. Modulate the bit sequence into modulation symbols according to the modulation scheme used for each layer and the mapping.

3. Allocate the modulation symbols to the corresponding transmission layers based on the mapping

FIG. 9 describes an example of joint CW to modulation and layer mapping with a same modulation scheme used for all layers. Assuming the reliability order (that is, the reliability ranking) of the combinations of the modulation bits and MIMO layers are given by L1, b (1) b (2) > L2, b (1) b (2) > L1, b (3) b (4) > L2, b (3) b (4) > L3, b (1) b (2) > L4 b (1) b (2) > L3, b (3) b (4) > L4, b (3) b (4) , where L1, L2, L3 and L4 refers to Layer 1, Layer 2, Layer 3 and Layer 4, notations b (1) , b (2) …are the 1st and the 2nd bit of bits carried by a modulation symbol. The notations b (1) , b (2) , …are the same as b₁, b₂…used in some other example of this disclosure. As described before, b (1) and b (2) have the same reliability, so we don’t need to rank between them or we can take any rank between them for the mapping purpose, same applies to b (3) and b (4) .

After obtaining the reliability tier ranking, the priority ordered coded bit sequence is mapped to the modulation symbols and the MIMO layers based on the reliability tier ranking. To implement the mapping scheme, one example is to first divide the priority ordered coded bit sequence into P equal size subblocks, where P is the same as the number of the reliability tiers. This process can also be considered a bit interleaving process which write the bit sequence into multiple shorter vertical sequences and read them horizontally for modulation and layer mapping. The P subblocks or vertical sequences is mapped to P reliability tiers following the reliability order, i.e., the most reliable tier is mapped to the first vertical sequence or first subblock, which corresponds to the earliest or highest priority coded bits based on the priority ordering of the coded bit sequence.

After mapping the priority coded bit sequence to the reliability tiers based on combination of modulation bit location and layers, the next step is to map the bit sequence to the modulation symbols and the MIMO layers. For the modulation mapping, the modulated symbols are selected horizontally in order by combining bits from same MIMO layers. In the example, the modulation scheme for Layer 1 is 16QAM, which contains 4 bits. Therefore the first modulation symbol, which is to be allocated to Layer 1, is formed by selecting 1 bit each from the subblocks or vertical sequence that corresponding to (L1, b (1) ) , (L1, b (2) ) , (L1, b (3) ) and (L1, b (4) ) tiers, i.e., from the 1^st, 2^nd, 5^th and 6^th vertical sequences to map a modulation symbol and further allocated to the first MIMO layer. In FIG. 9, different bits from the same modulation symbol are marked using the same shape and the same shape is marked to be mapped to the corresponding transmission layer before precoding.

FIG. 10 illustrates a more general example of the joint modulation and layer mapping scheme for the CW mapping with per layer modulation adaptation. In this example, different modulations (i.e., different modulation schemes) in different layers are used in the joint modulation and layer mapping process. Each CW is mapped to 4 layers, which mean each CB of the CW is also mapped across the 4 layers. Each layer is applied with a potentially different modulation scheme, which is adapted based on the channel quality of each layer. In the example, 64QAM, 16QAM, 16QAM and QPSK modulation schemes are adopted for Layer 1 to layer 4, which corresponds to modulation order m_l equals 6, 4, 4, 2, respectively.

For the joint mapping process, first the priority ordered coded bit sequence are first divided into P equal sized shorter sequences or subblocks, these shorter sequences may be called vertical sequences to visually match the figure. P is the same as the total number of reliability tiers, which is given byAssume the reliability ranking for the combinations of layer indexes and bit locations of the modulation symbols are given by L1, b (1) b (2) > L2, b (1) b (2) > L3, b (1) b (2) > L4, b (1) b (2) >L1, b (3) b (4) > L2, b (3) b (4) > L3, b (3) b (4) > L1, b (5) b (6) . The 16 vertical sequences are mapped to the 16 reliability tiers of different combinations of the layer indexes and the bit locations. After that take 1 bit of each bit location corresponding to the same MIMO layers and map them to a modulation symbol and then allocate the modulation symbol to the corresponding MIMO layers. In the example, the first bit of the vertical sequences that corresponding to (L₁, b₁) , (L₁, b₂) , …, (L₁, b₆) , with a total of 6 bits, will be mapped to a 64QAM modulation constellation through the modulation process, which result in a complex value allocated to layer 1. The corresponding bit locations and the modulation symbols mapped to the layer 1 have been shown as the circular shape in the figure. Similarly, we have first bit of the vertical sequences corresponding to L2 layer, with a total of 4 bits, mapped to a 16QAM modulation constellation through modulation process, which result in a complex value allocated to layer 2. After mapping all the first bit to a modulation symbol corresponding to each MIMO layer. The complex values represent the first modulation symbols of each layer form a vector of complex values with dimension equals to the number of layers. This vector is then multiplied by the precoder through precoding process for further processing and transmission. The 2^nd bit and following bits of each reliability tier will go through the same process for joint modulation and layer mapping sequentially.

In the following, some implementations of the joint CW to modulation and mapping process will be described in more detail. Consider the step we already obtained a priority ordered coded bit sequence through rate matching and the optional coded bit priority ranking process.

The remaining steps for joint CW to modulation and mapping process may include:

1. Subblock interleaving

FIG. 11 illustrates a subblock interleaving process with modulation adaptation. The input priority ordered coded bit sequence is first divided equally or nearly equally intosublocks. In this example, P=16. Each subblock corresponds to a reliability tier of a specific layer index and modualtion bit location combinations based on the joint modulation and layer reliability ranking as shown in the figure. The ranking of the combiantion in the example is given by (L1, b (1) b (2) > L2, b (1) b (2) > L3, b (1) b (2) > L4, b (1) b (2) >L1, b (3) b (4) > L2, b (3) b (4) > L3, b (3) b (4) > L1, b (5) b (6) . The subblock interleaver is used to rearrange subblocks such that the overall bit sequence following the order of layers first, then different bit locaitons of the modulated symbols of the MIMO layer. Basically after the subblock interleaver, the subblocks in order corresponds to (L1, b (1) ) (L1 b (2) ) (L1 b (3) ) (L1 b (4) ) (L1 b (5) ) (L1 b (6) ) (L2 b (1) ) (L2 b (2) ) (L2 b (3) ) (L2 b (4) ) (L3 b (1) ) (L3 b (2) ) (L3 b (3) ) (L3 b (4) ) (L4 b (1) ) (L4 b (2) ) , as shown in FIG. 11.

2. Bit interleaving

FIG. 12 is an example of bit interleaving, modulation and layer mapping procedure. Referring to FIG. 12, after subblock interleaving, a bit interleaving process is used by writing the input sequence vertically and read the output bit horizontally. The process is shown in the left part of the FIG. 12.

Note that write vertically is basically divide the input bit sequence into P subblocks, then read horizontally is to take bit sequentially from each subblock, e.g., take 1^st bit of each subblock sequentially, then take 2^nd bit of each subblock sequentially, …, etc. until all bits of the subblocks are taken. The width of the horizontal taken is P.

3. Modulation mapping

The bit sequence after bit interleaving is then going through modulation process. The modulation process is to map the modulation symbol of each layer in a round robin fashion, and the output of the modulation mapping process is a sequence of complex values, with each complex value represents a modulation symbol. For example, for first 16 bits, first 6 bits are mapped to the 1^st 64QAM symbol of layer 1, the next 4 bits are mapped to the 1^st 16QAM symbol of layer 2, then next 4 bits are mapped to the 1^st 16QAM symbol of layer 3, the last 2 bits are mapped to the 1^st QPSK symbol of layer 4. Then for the next 16 bits, first 6 bits are mapped to 2^nd 64QAM symbol of layer 1, the next 4 bits are mapped to the 2^nd 16QAM symbol of layer 2, then next bits are mapped to the 2^nd 16QAM symbol of layer 3, and the last 2 bits are mapped to the 2^nd QPSK symbol of layer 4 etc. This modulation mapping process is shown in the middle part of the figure.

4. Layer mapping

For L MIMO layers, each L consecutive modulated symbols with L complex values are mapped to the corresponding L layers. This is obtained by forming the L complex values of the L modulated symbols as a vector of complex values of dimension L. The vector of complex values is sent as the input of the MIMO precoder. The vector is multiplied by a precoder matrix with dimension L×N to produce a vector of complex values with length N for further resource mapping and transmission on physical antennas. In the example, the 16 bits mapped to 1st symbol of each layer become a vector of complex symbols as an input vector for precoding. Similarly, we map each of the following 16 bits to a vector of complex symbols for the 2^nd precoder input. This process is allocating modulation symbols in round robin fashion to different MIMO layers, but the modulation symbols may correspond to different modulation levels. The layer mapping process is shown in the right part of the figure for the example.

To further illustrate the process, the following gives a more detailed example on the joint CW to modulation and layer mapping process.

The process can be applicable to LDPC code, Polar code or other FEC code. In the following, we use LDPC code as an example for the rate matching process. Note that some of the common process for coding, rate matching, modulation, scrambling, layer mapping and other procedures may not be repeated and can be referred to, for example, [3GPP TS 28.212 V16.7.0] . The information bits for each code block are encoded by a mother code to produce a coded bit sequence d₀, d₁, d₂, ..., d_N-1, which includes a plurality of coded bits and is the input sequence to rate matching.

1. Rate matching process

The rate matching for LDPC code is defined per code block and may include processes of bit selection, subblock interleaving and bit interleaving. The input bit sequence to rate matching is d₀, d₁, d₂, ..., d_N-1 . The output bit sequence after rate matching is denoted as f₀, f₁, f₂, ..., f_E-1.

1.1. Bit selection

The bit sequence after encoding d₀, d₁, d₂, ..., d_N-4 is written into a circular buffer of length N_cb for the r-th coded block. N_cb is usually equal to encoder output bit length of the mother code, and may be modified for low buffer rate matching (LBRM) , details to determine N_cb can be refered to Section 5.4.2.1 of [3GPP TS 38.212 V16.7.0] .

The output bit sequence is selected from the input sequence based on the redundancy version. Example of this process can be referred to [3GPP TS 28.212 V16.7.0] . The output bit sequence from bit selection for each code block (CB) is given by e₀, e₁, e₂, ..., e_E-1

1.2. Subblock interleaving

The bits inputted to the sub-block interleaver are the coded bits e₀, e₁, e₂, ..., e_E-1. This input sequence is also considered to be the priority ordered input sequence in previous description. The coded bits e₀, e₁, e₂, ..., e_E-1 are divided into P sub-blocks, where P is the number of reliability tiers. As described earlier, P may be given bywhere L is the number of transmission layers the transport block is map to. Note that the sequence length E determined in the bit selection process may has result in that E is divisible by P, so E/P can be an integer.

The bits outputted from the sub-block interleaver are denoted as y₀, y₁, y₂, ..., y_E-1, generated as follows:

As above, f (i) is the sub-block interleaver pattern. P is the number of subblocks into which the first bit sequence is divided, E is a length of the first bit sequence, thus E/P is the number of bits per subblock or subsequence includes. is the subblock index for bit y_n , f (i) is the subblock index for bit e_J (n). mod (n, E/P) is the bit index of y_n within subblock i , which is equal to the bit index of e_J (n) within subblock f (i) as captured by equation J (n) = f (i) × (E/P) +mod (n, E/P) ; Equation y_n=e_J (n)maps the bits of subblock f (i) in the input bit sequence e to the same bits of subblock i in the output bit sequence y. Note that the above implementation is just one way of implementation of subblock interleaving process. There are other alternative ways to achieve the same results and not described here in detail for simplicity. For example, a reverse function of f (i) , denoted as g (i) , can be defined as the subblock interleaver instead. In this case, instead of map subblock f (i) of input bit sequence e to subblock i of output bit sequence y, we can map subblock i of input bit sequence e to subblock g (i) of output bit sequence y.

The subblock interleaver pattern f (i) represents reliability ranking of tiers or the reliability ranking of the combination of transmission layer and bit location of modulation symbols, which we refer to the joint modulation and layer reliability ranking. f (i) can be indicated by the network or BS, e.g., in the DCI that is scheduling the transmission; f (i) can also be a fixed pattern, which may be described by a look up table or a function; f (i) can also be generated based on a fixed rule.

To interpret the relationship between subblock interleaver pattern f (i) and the joint modulation and layer tier reliability ranking. Let’s define a single tier index i (0≤i≤P-1) , which is a function of layer index l (1≤l≤L) , and bit location index j (1≤j≤m_l) for bit b_j of the modulation scheme with modulation order m_l in layer l , such that where a notation x is an index for summation. Therefore, it can be interpreted that a tier index, which starts with i=0, which corresponds to 1^st bit of modulation symbol of first layer, then i=1 corresponds the 2^nd bit of the modulation symbol of the first layer, …, until i=m₁-1 corresponds to the last bit of modulation symbol of first layer, then goes to 2^nd layer, ..., until i=P-1 corresponds to the last bit of the modulation symbol in the last layer, for a total of P tiers. Note that the layer index l and bit location index j start at 1 (which is one) is to be consistent with the description in previous examples. However, you can also define l and j starts at 0 and change the function accordingly, e.g. toor more generally, any one to one mapping of the single index i from the pair of indexes l and j.

Now if we rank the reliability of tier i from the most reliable tier to the least reliable tier, then the subblock interleaver pattern f (i) represents the ranking of tier i among all tiers, i.e., f (i) is the location of the tier i in the ranking. More specifically, if the reliability ranking is given by R (i₀) ≥R (i₁) ≥R (i₂) …≥ R (i_P-1) , where (i₀, …i_P-1) are a sequence of the tier index ranked from highest reliability to lowest reliability. R (i) is a tier reliability function for the ranking purpose, (higher R (i) means higher reliability for tier i) , which can be defined as specific functions but it may not be defined in some scenario as long as the tier ranking, represented by the tier ranking sequence (i₀, …i_P-1) , can be obtained. Then subblock interleaver pattern f (i) is given by f (i_k) =k for 0≤k≤P-1, i.e., f (i) is the location of the tier i in the tier ranking sequence.

Now taking the example shown in FIGS. 9～10, as described earlier for the examples, the modulation order m_l is 6, 4, 4 and 2 for Layer 1 to 4, respectively and P=16 tiers; the ranking order from the most reliable to the list reliable for the tiers are given by (L₁b₁) , (L₁b₂) , (L₂b₁) , (L₂b₂) , (L₃b₁) , (L₃b₂) , (L₄b₁) , (L₄b₂) , (L₁b₃) , (L₁b₄) , (L₂b₃) , (L₂b₄) , (L₃b₃) , (L₃b₄) , (L₁b₅) , (L₁b₆) . Now this corresponds to the tier ranking for the pair of the layer index l and bit index j (l, j) as the follow order (1, 1) , (1, 2) , (2, 1) , (2, 2) , (3, 1) , (3, 2) , (4, 1) , (4, 2) , (1, 3) , (1, 4) , (2, 3) , (2, 4) , (3, 3) , (3, 4) , (1, 5) , (1, 6) .

If we use the single tier index defined based onwe obtain the tier ranking sequence (i₀, …i_P-1) = (0, 1, 6, 7, 10, 11, 14, 15, 2, 3, 8, 9, 12, 13, 4, 5) . Then based on f (i_k) =k, we obtain the subblock interleaver pattern f (i) for the example as given by the following table 1. On the other hand, if the reverse function of f (i) : g (i) is used for the subblock interleaving implementation instead as described earlier, then g (i) is the ranking of tier i among all tiers, i.e., g (i) is given by the tier ranking sequence, in this example, g (i) = (0, 1, 6, 7, 10, 11, 14, 15, 2, 3, 8, 9, 12, 13, 4, 5) for i=0, 1, …, 15, where i is the location in the tier ranking sequence.

Table 1: Subblock interleaver pattern f (i)

After subblock interleaving, the bit sequence has been changed from the left to the right in FIG. 10.

1.3 Bit interleaving.

The bit sequence y₀, y₁, y₂, ..., y_E-1 from the subblock interleaver output is interleaved to bit sequence f₀, f₁, f₂, ..., f_E-1, according to the following, where the value of P is the number of tiers or the number of the subblocks, as given bywhere L is the number of transmission layers the transport block is map to.

This process corresponds to the bit interleaving process in FIG. 12, where the input bit sequence after subblock interleaving or ranking process, is written vertically and read horizentally, with horizental width thta equals to the number of tiers P. Equivalently, it can be implented by written the bit sequence horizentally and read vertically. The process is to prepare the bit sequence in the order of modulation symbols, then layers for the modulation and mapping.

2. Code block concatenation

If there are multiple code blocks, optionally, the rate matching output of multiple code blocks can be concatenated to a single coded bit stream via a code block concatenation process. Alternatively, each code block can be modulated and mapped to multiple transmission layers seperately. An example of code block concatenation process similar to Section 5.5 of [3GPP TS 38.212 V16.7.0] .

3. Physical uplink or downlink shared channel processing

3.1 Scrambling

For each codeword, the block of bits a (0) , …, a (M_bit-1) , whereis the number of bits in the codeword transmitted on the physical channel, may be scrambled prior to modulation, resulting in a block of scrambled bits codeword q. The block of bits is obtained from the output of the coded bit sequence for a single code block or multiple code blocks after code block concatenation described above. Examples of the optional scrambling process can be found on Section 6.3.1.1 of [3GPP TS 38.211 V17.0.0] for uplink data transmission and Section 7.3.1.1 of [3GPP TS 38.211 V17.0.0] for downlink transmission.

3.2 Modulation

For each codeword q, the UE shall assume the block of optionally scrambled bitsare modulated using modulation scheme for each layer in order and in a round robin fashion, resulting in a block of complex-valued modulation symbols d (0) , …, d (M_symb-1) . In another word, each set ofbits, are modulated in order using a set of L modulation schemes with modulation order m₁, m₂, …, m_L , resulting in a set of L complex-valued modulation symbols, (d (n·L+0) , d (n·L+1) , …, d( (n+1) ·L-1) ) respectively, where L is the number of layers and m_l is the modulation order for layer l.

Table 2: Examples of modulation schemes

3.3 Layer mapping

The UE shall assume that complex-valued modulation symbols for each of the codewords to be transmitted are mapped onto one or several layers. The codeword is mapped to a number of transmission layers according to the following: For notational simplicity, to be consistent with the tier ranking notation, and without loss of generality, we assume the codeword of interest is mapped to L layers with layer index from 1 to L. In practice, the codeword may be mapped to L layers with other layer index, e.g. layer index from 0 to L-1, or there are multiple codeword, and the codeword may be mapped to L layers among a total of more than L layers, e.g., with layer index from k to L+k-1. These indices should be one-to-one mapped in order to the layer index 1 to L used for the ranking purpose.

Complex-valued modulation symbols d (0) , …, d (M_symb-1) for this codeword shall be mapped onto the layerswhere L is the number of layers this codeword is mapped to andis the number of modulation symbols per layer andx ^(j) (i) = d (L·i+j-1) (i= 0, 1, …, M_symb) (j=1, 2, …, L) .

Or more generally if the code word is mapped to Layer index k to L+k-1, k=0, 1, …, x ^(j) (i) = d (L·i+j-k) (i=0, 1, …, M_symb) (j=k, 2, …, L+k-1) .

After layer mapping, the block of vectors may be mapped to antenna port, going through the multi-antenna precoding process, then through resource mapping, which includes mapping to time and frequency resources for transmission.

To determine the ranking of the combination of the modulation bit (which also refers to the bit location of the modulation symbol) and the transmission layer, the network or BS may determine the ranking based on CSI feedback information. The ranking can be based on channel quality feedback for each layer, e.g., based on signal to interference plus noise ratio (SINR) or CQI of each layer among all layers mapped to this CW. The ranking can also be based on layer ranking feedback, for which, examples used for some special preconfigured ranking rules are given in this disclosure. The information used for determining the ranking of the combination can also be based on information of a statistical model or statistical results (or statistic information) regarding L transmission layers, L is the number of the transmission layer mapped to one codeword. Optionally, part or all of the statistical results or parameters for the statistical model may be from the CSI feedback from the UE. As examples in some embodiments, the ranking of the combination of the modulation bit and the transmission layer could be a ranking based on a reliability of the combination. In another word, the ranking may be a reliability ranking.

In an implementation, the BS may compute the ranking of the combinations based on feedback information from the UE such as CQI, SINR or any channel quality measures of per layer or per layer group, and then indicate the ranking of the combination to the UE for the joint modulation and transmission layer mapping. Alternatively, UE may measure CQI, SINR or any channel quality measures of each layer or each layer group itself, compute the ranking of the combination, and then report the ranking of the combination to the network or the BS.

In some scenarios, instead of a fully flexible ranking of the combination of a transmission layer index and a bit location index, the BS or the UE may determine the ranking based on a preconfigured special rule. These ranking methods may be defined for one of the following reasons:

1) The fully flexible ranking may require significant signaling overhead to indicate the ranking used for the CW to modulation and transmission layer mapping process, which may not be desirable.

2) The BS or the network may not have enough information to determine a fully flexible ranking, therefore, it make sense for the BS or the network to use a simplified ranking rule based on limited information BS have while the performance can still benefit significantly from the simplified ranking rule.

Accordingly, due to the second reason listed above, after the BS determined the ranking of the combination, the BS transmitting information used for the UE to determine the ranking, the UE uses the received information and one or more special rules to finally determine the ranking of the combinations, and vice versa. Optionally, the special rules can be preconfigured, predefined, or indicated by signaling, etc.

Different ways can be used to order (or rank) reliability tiers for layer and modulation mapping. The followings are some examples of the special rules.

Rule 1: Modulation bit location always are considered first and then the transmission layers.

In this rule, priority of the bit location of the modulation symbol is higher than priority of the transmission layer. Specifically, the ranking process may be as follows: the BS or the UE selects first two-bit location first, then go through all the transmission layers (for example, the L transmission layers mapped to one codeword) in an order starting from the transmission layer with the highest ranking/priority or highest channel quality to the lowest one, then selects next two-bit locations, then go through all the transmission layers that contains the corresponding bit locations in the order of from the highest ranking/priority or highest channel quality to the lowest, …, and selects last two-bit locations, and go through all the transmission layers that contains the last two bit locations in the order of from highest ranking/priority or the highest channel quality to the lowest one. Note that, as it is known that the 1st and 2nd bit locations of the modulation symbol have the same reliability or priority, they are considered together in the ranking, similarly. Moreover, in the ranking process, when select two consecutive and adjacent bit locations going through the transmission layers from the highest reliability one to the lowest one, if a certain transmission layer doesn’t contain the corresponding bit locations, the certain transmission layer is skipped.

Rule 2: Layer quality always are considered first and then bit locations of modulation symbols.

In this rule, priority of the transmission layer is higher than priority of the bit location of the modulation symbol. Specifically, the ranking process may be as follows: the BS or the UE selects a transmission layer with the highest channel quality first, then go through all bit locations from the first bit location to the last bit location based on the modulation scheme corresponding to this transmission layer; then it selects a transmission layer with the second highest channel quality, and go through all bit locations in an order from the first bit location to the last bit location based on the modulation scheme corresponding to this transmission layer; …, finally, it selects the transmission layer with the lowest channel quality, then go through all bit locations from the first to the last bit location based on the corresponding modulation scheme of this transmission layer.

For the rule 1, assuming modulation adaptation is adopted, the average SNR of each modulation bits may be similar, therefore, earlier bit locations in modulation is likely more important than later bit location. The more important bits form the codeword will be mapped to higher reliability bit locations, which is an advantage of the Rule 1.

For the rule 2, assuming modulation adaptation is adopted, the average SNR of each modulation bits may be similar, therefore, earlier bit locations in modulation is likely more important than later bit location. The more important bits form the codeword will be mapped to higher reliability bit locations, which is an advantage of the Rule 2.

In the following, two examples are given in two different scenarios.

In a first scenario, it is assumed that channel quality of each layer is already ranked based on a nature ascending (or descending) order of layer index from a layer with the highest channel quality to a layer with the lowest channel quality. For example, the layer with higher channel quality corresponds to a lower layer index, and vice versa. This can be achieved by different mechanisms, for example, the BS or the network can arrange a mapping of the layer to an antenna port, and a mapping of the antenna port to physical antennas in such a way that the layer with the highest channel quality appears on the layer with the lowest index, and columns of a precoder corresponding to each layer can also be arranged accordingly. Note that, examples with an ascending order of layer index representing the highest channel quality to the lowest channel quality may be given in the following embodiments, however, a descending order of the layer index also can be applied similarly.

In a first example, we assume there is no layer-based modulation adaptation, i.e., the modulation scheme used for all layers mapped to one CW is the same. There are total of 4 layers: L0, L1, L2, L3 with corresponding layer index l=0, 1, 2 and 3, respectively. The modulation scheme for all 4 layers is 16QAM, with a modulation order that equals to 4, i.e., 4 bits per modulation symbol. A ranking of layers is assumed to be already done based on the nature ascending order of layer indexes, i.e., L0>L1>L2>L3.

If the Rule 1 with “bit locations of modulation symbols first and transmission layers second” is used, the reliability ranking for the combination (or pair) of the bit location and the layer index (from the highest reliability to the lowest reliability) is given by (L0, b (1) ) , (L0, b (2) ) , (L1, b (1) ) , (L1, b (2) ) , (L2, b (1) ) , (L2, b (2) ) , (L3, b (1) ) , (L3, b (2) ) , (L0, b (3) ) , (L0, b (4) ) , (L1, b (3) ) , (L1, b (4) ) , (L2, b (3) ) , (L2, b (4) ) , (L3, b (3) ) , (L3, b (4) ) , where b (j) represents j-th bit of a modulation symbol, same meaning as the notation b_j, j=1, 2, …, m, where m is the modulation order.

If the Rule 2 with “transmission layers first and bit locations of modulation symbols second” is used, the reliability ranking of the combination of the bit location and the layer index is given by (L0, b (1) ) , (L0, b (2) ) , (L0, b (3) ) , (L0, b (4) ) , (L1, b (1) ) , (L1, b (2) ) , (L1, b (3) ) , (L1, b (4) ) , (L2, b (1) ) , (L2, b (2) ) , (L2, b (3) ) , (L2, b (4) ) , (L3, b (1) ) , (L3, b (2) ) , (L3, b (3) ) , (L3, b (4) ) .

In a second example, layer-based modulation adaptation is adopted, i.e., different layers mapped to the same CW may use different modulation schemes. In the example, the modulation scheme for each layer is given by L0: 64QAM, L1: 16QAM, L2: 16QAM, L3: QPSK, where the modulation order is given by 6, 4, 4, 2, respectively.

If the Rule 1 with “bit locations of the modulation symbols first and transmission layers second” is used, the reliability ranking of the combination of the bit location and the transmission layer is given by (L0, b (1) ) , (L0, b (2) ) , (L1, b (1) ) , (L1, b (2) ) , (L2, b (1) ) , (L2, b (2) ) , (L3, b (1) ) , (L3, b (2) ) , (L0, b (3) ) , (L0, b (4) ) , (L1, b (3) ) , (L1, b (4) ) , (L2, b (3) ) , (L2, b (4) ) , (L0, b (5) ) , (L0, b (6) ) .

If the Rule 2 with “transmission layers first and bit locations of modulation symbols second” is used, the reliability ranking of the combination of the bit location and the layer index (i.e., the transmission layer) is given by (L0, b (1) ) , (L0, b (2) ) , (L0, b (3) ) , (L0, b (4) ) , (L0, b (5) ) , (L0, b (6) ) , (L1, b (1) ) , (L1, b (2) ) , (L1, b (3) ) , (L1, b (4) ) , (L2, b (1) ) , (L2, b (2) ) , (L2, b (3) ) , (L2, b (4) ) , (L3, b (1) ) , (L3, b (2) ) .

In a second scenario, the layer index is not ranked based on channel quality, i.e., the order of the layer index does not imply any order of channel quality. In this case, some additional information may be needed for the ranking rule, e.g., a ranking of channel quality of the layers. The ranking of layers’ channel quality may be obtained from channel measurement or CSI feedback.

If the previous first example is used, i.e., without layer-based modulation adaptation used and all 4 layers using 16QAM modulation, and assuming the ranking of layer quality is given by L1>L2>L0>L3.

If the Rule 1 with “bit locations of modulation symbols first and transmission layers second” is used, the reliability ranking is given by (L1, b (1) ) , (L1, b (2) ) , (L2, b (1) ) , (L2, b (2) ) , (L0, b (1) ) , (L0, b (2) ) , (L3, b (1) ) , (L3, b (2) ) , (L1, b (3) ) , (L1, b (4) ) , (L2, b (3) ) , (L2, b (4) ) , (L0, b (3) ) , (L0, b (4) ) , (L3, b (3) ) , (L3, b (4) ) .

If the Rule 2 with “transmission layers first and bit locations of modulation symbols second” is used, the reliability ranking of the combination of the bit location and the layer index is given by (L1, b (1) ) , (L1, b (2) ) , (L1, b (3) ) , (L1, b (4) ) , (L2, b (1) ) , (L2, b (2) ) , (L2, b (3) ) , (L2, b (4) ) , (L0, b (1) ) , (L0, b (2) ) , (L0, b (3) ) , (L0, b (4) ) , (L3, b (1) ) , (L3, b (2) ) , (L3, b (3) ) , (L3, b (4) ) .

If the second example is used, where there is layer-based modulation adaptation, with the modulation schemes for each layer given by L0: 16QAM, L1: 64QAM, L2: 16QAM, L3: QPSK, where the modulation orders are given by 4, 6, 4, 2, respectively. And assuming the ranking of layer quality is given by L1>L2>L0>L3, then:

If the Rule 1 with “bit locations of the modulation symbols first and transmission layers second” is used, the reliability ranking is given by (L1, b (1) ) , (L1, b (2) ) , (L2, b (1) ) , (L2, b (2) ) , (L0, b (1) ) , (L0, b (2) ) , (L3, b (1) ) , (L3, b (2) ) , (L1, b (3) ) , (L1, b (4) ) , (L2, b (3) ) , (L2, b (4) ) , (L0, b (3) ) , (L0, b (4) ) , (L1, b (5) ) , (L1, b (6) ) ;

If the Rule 2 with “transmission layers first and bit locations of modulation symbols second” is used, the reliability ranking of the combination of the bit location and the layer index is given by (L1, b (1) ) , (L1, b (2) ) , (L1, b (3) ) , (L1, b (4) ) , (L1, b (5) ) , (L1, b (6) ) , (L2, b (1) ) , (L2, b (2) ) , (L2, b (3) ) , (L2, b (4) ) , (L0, b (1) ) , (L0, b (2) ) , (L0, b (3) ) , (L0, b (4) ) , (L3, b (1) ) , (L3, b (2) ) .

In some scenarios, if the modulation scheme for each layer is already known, then the reliability ranking of the layers can be based on a modulation order. For example, if the above second example is used, the modulation schemes for each layer are given by L0: 16QAM, L1: 64QAM, L2: 16QAM, L3: QPSK. Therefore, the modulation orders are given by 4, 6, 4, 2, respectively. The ranking of the layers can be determined based on additional information that a higher modulation order a later takes a higher reliability the layer has, based on the additional information, the reliability ranking of the layers are determined as L1> (L2, L0) >L3. In the case where the modulation order is the same for multiple layers, the ranking of the layers using the same modulation order may be based on other rules, e.g., based on the nature ascending (or descending) order of layer indexes corresponding to the same modulation scheme among the layer mapped to one codeword. For example, if the ascending order of the layer indexes of the layers corresponding to the same modulation order represents an ascending order of the reliability of the layers, the reliability of layers L2 and L0 can be determined as L2>L0. Then the reliability of the layers can be determined as L1> L2>L0>L3. The additional information may be preconfigured or default information. Alternatively, the ranking of the layers using the same modulation order may be based on CSI feedback.

The advantage of the special rule-based ranking may provide minimum signaling overhead since the BS or the UE just needs additional information such as layer ranking or modulation order itself to determine the ranking of the combination. It can still capture majority of the performance gain and require minimum feedback knowledge if the additional information is from the feedback.

FIG. 13 shows a basic signaling and transmission procedure for DL (left figure) and UL (right figure) transmission. In DL transmission, BS may optionally send reference signal (RS) for channel measurement, and the reference signal may include CSI-RS, PT-RS, DMRS, etc. UE may then optionally perform channel measurement, usually based on the reference signal (e.g. CSI-RS) , then UE send CSI feedback to the BS, which may include information to help BS for joint CW to QAM and layer mapping. BS then determine a ranking of reliability of a combination of a bit location and a transmission layers based on feedback and/or specific preconfigured rules, and then perform encoding, modulation and layer mapping, including the joint CW to QAM and layer mapping process based on the determined ranking of the combination of the transmission layer and the bit location. Then BS sends DCI to schedule the PDSCH (i.e., DL data) transmission. The DCI may additionally indicate the ranking of the combination for UE to understand the ranking used for the joint CW to QAM and layer mapping process. Then UE use the information carried by the DCI to help decoding PDSCH.

In the uplink transmission, the RS for channel measurement may be optionally sent by the UE (e.g. via SRS) . BS may perform channel measurement and determine a ranking of a combination of a transmission layer and a bit location of a modulation symbol based on either channel information or specific preconfigured rules or both of them. Then BS may send a DCI to schedule a PUSCH (i.e., UL data) transmission. The DCI may additionally indicate the ranking of the combination for UE to understand the ranking used for the joint CW to QAM and layer mapping process. Then UE perform encoding, modulation and layer mapping, including the joint CW to QAM and layer mapping process and send the PUSCH to BS based on the information from DCI.

The joint CW to QAM and layer mapping is performed by the BS or the UE based on mapping information associated with a combination of a transmission layer and a bit location of a modulation symbol. For example, the mapping information may indicate the ranking of the combination, or the mapping information is associated with information indicating the ranking of the combination, or the mapping information is associated with information that can be used to determine the ranking of the combination. In addition, the mapping information may be the ranking of the combination, or a subblock interleaving pattern, etc.

FIG. 14 is a schematic flow chart of a communication method 200 according to embodiment of the present application. Some steps of the method 200 are implemented by a first device or a chip configured in the first device, and some steps of the method 200 are implemented by a second device or a chip configured in the second device. The first device also can be referred as a transmitting device, and the second device also can be referred as a receiving device.

At step 210, a first device maps, based on mapping information, a coded bit sequence including a plurality of coded bits to modulation symbols and L transmission layers.

For the first device, the mapping information is used for mapping the coded bit sequence to the modulation symbols and the L transmission layers. As a transmitting device, the first device transmits a signal via the L transmission layers using the mapping information, and the first device needs to provide information to the second device to let the second device obtain the mapping information and then demodulate the received signal based on the mapping information.

At step 220, the first device transmits first information to the second device. The second device receives the first information accordingly.

Based on the first information, the second device determines the mapping information.

There are many ways to make the second device determine the mapping information based on the first information. In other words, the first information may include or indicate different information in different implementations for the device to determine the mapping information, which is described in the following embodiments.

At step 230, the second device demodulates, based on the mapping information, a signal from the first device transmitted via the L transmission layers.

According to the embodiments of this application, the mapping information is used for the first device to perform a mapping operation described in step 210, and it is used for the second device to perform demodulating on the received signal from the first device.

In an embodiment, the method 200 may be used in a downlink (DL) communication, which means the first device is the BS and the second device is a UE. In the DL communication, the BS maps, based on the mapping information, a coded bit sequence including a plurality of coded bits to modulation symbols and L transmission layers, L is an integer greater than one. The BS may transmit first information to the UE, and the first information is used for the UE to determine the mapping information. The L transmission layers are mapped to one codeword.

There are different ways can be used to indicate joint layer quality and modulated bit reliability ranking (that is, the ranking of the combination of a bit location of a modulation symbol and a transmission layer) , and it depends on how the ranking is determined and used for the joint CW to QAM and layer mapping.

The following are some examples of indication schemes can be used. The indication schemes can be applied in either the UL transmission or the DL transmission. For example, in the UL transmission or the DL transmission, the BS transmit information to help the UE to determine the ranking. Based on the received information, the UE may decode the PDSCH in the DL transmission or perform the joint CW to QAM and layer mapping in the UL transmission. In the following embodiments, the information transmitted by the BS to help the UE to determine the ranking can be referred to as first information for simplification.

As described earlier, different ways can be used to indicate the ranking, depending on how the ranking is determined.

The first information is transmitted by the BS to the UE to determine the ranking of the combination. Therefore, the first information varies if different methods or ways are taken to determine the ranking of the combination. For example, the first information may be the ranking of the combination itself, a ranking of the L transmission layers, a ranking of more than one transmission layer group which consists of the L transmission layers, a ranking of part of the L transmission layers corresponding to a same modulation order, or a subblock interleaver pattern, etc.

In some of the above implementations, additional information is also needed for the UE to determine the ranking of the combination. Optionally, in an embodiment, the additional information may be provided by the BS, or it is preconfigured in advance, or it may be implicitly indicated with the first information. In an embodiment, the additional information may be the specific preconfigured ranking rules. These implementations will be elaborated in the following.

1. Fixed special ranking rules

If the ranking is determined based on a special ranking rule, the BS transmits the first information to the UE. The first information may indicate one or more of, but not limited to: layer ranking information, modulation order per layer, layer ranking information for layers have the same modulation order. The special ranking rule can be referred to the description in above embodiments, for example, the Rule 1, the Rule 2, which is not repeated herein.

The layer ranking information may indicate a ranking of L transmission layers mapped to one codeword. The ranking of the L transmission layers may be obtained based on channel qualities of the L transmission layers. A transmission layer that has a higher channel quality may have a higher priority in the ranking.

In an implementation, if some of the L transmission layers corresponding to a same modulation order, the first information may indicate a ranking of the transmission layers that corresponds to the same modulation order. For example, there are two transmission layers corresponding to a same modulation order of 4, the first information may indicate a ranking of the two transmission layers. The transmission layers corresponding to the same modulation order can be referred to as a subset of the transmission layer. Optionally, there may be one or more subsets, which is not limited. If there are more than one subset, the first information indicates layer ranking information corresponding to the more than one subset, respectively.

The UE determines the ranking of the combination based on the received first information and additional information such as the preconfigured rules or some other information.

For example, assuming that the first information indicates the ranking of L transmission layers, and a preconfigured ranking rule is known to the UE in advance. Moreover, the BS may further indicate modulation schemes for each transmission layer to the UE. Then the ranking of the combination can be determined by the UE based on the received first information, the preconfigured ranking rule and the modulation schemes for each transmission layer. In this example, the preconfigured ranking rule and the modulation schemes for each transmission layer are examples of the additional information.

In another example, the first information indicates the modulation schemes for the L transmission layers, respectively. It is implicitly indicated that a higher modulation order a transmission layer takes a higher reliability the transmission layer has. Therefore, a priority of a first transmission layer that adopts a modulation scheme corresponding to a higher modulation order is higher than a priority of a second transmission layer that adopts a modulation scheme corresponding to a lower modulation order. The UE can determine the ranking of the combination based on the first information and the preconfigured ranking rule. If there are some transmission layers adopt the same modulation scheme, the BS may provide additional information indicating a ranking of the transmission layers adopting the same modulation scheme.

2. Full ranking indication

In this implementation, the first information is used to indicate full ranking information or a compressed version of the full ranking information. Full ranking indication here refers to indicating a ranking of a combination of bit location and a layer index. As a comparison, in some other ways such as the foregoing fixed special ranking rules, or some that will be described in the following embodiments, the first information may indicate information that needs to be used jointly with preconfigured rules and/or additional information, or the first information may indicate a subblock interleaver pattern associated with the ranking of the combination, and both of which assist the UE to determine the ranking of the combination. However, the first information doesn’t explicitly include the ranking of the combination itself in these embodiments.

In some scenario, BS may configure a limited number of possible choices of ranking of the combination of bit location and layer index among all possible rankings in advance in semi-static configurations (e.g., in RRC signaling) , then in dynamic signaling (e.g. in DCI) . BS may indicate one choice among the limited choices of the ranking configured in advance.

3. Configurable ranking rules

Note that, the special rule such as the rule 1 or the rule 2 is preconfigured or fixed at the UE side, and the BS doesn’t need to indicate it to the UE. But the configurable ranking rules means that which rule, among kinds of rules, is used to determine the ranking of the combination needs to be configured, and the BS needs to indicate the chosen rule to the UE. The following are some examples such as a) , b) and c) for the BS to indicate the ranking rules.

a) the BS or the network may send specific configuration on the reliability ranking.

In this implementation, the specific configuration is configurable. For example, the specific configuration may be the rule 1 of “bit locations of the modulation symbols first and transmission layers second” or the rule 2 of “transmission layers first and bit locations of modulation symbols second” described above. The BS may send indication information used for indicating which rule is to be used in the joint CW to QAM and layer mapping process.

b) a couple of choices will be configured in advance (e.g. in RRC) or predefined in advance to reduce signaling overhead and DCI may indicate which ranking rules will be used.

In this implementation, a couple of special rules are configured in advance by the BS with an RRC configuration. Then, the BS may send DCI may indicate a choice between one or more of: a first rule of modulation bit first, a second rule of layer first and the full ranking indication. For example, the first rule and the second rule are configured in advance with the RRC configuration. Before the UL transmission or the DL transmission, the BS send DCI carrying information to tell the UE the first rule should be used in the UL transmission or the DL transmission.

c) UE can feedback preference among a fixed number of predefined ranking.

In this implementation, there may be more than one predefined ranking of the combination is configured both at the BS side and the UE side. Before the UL transmission or the DL transmission, the UE may send an index corresponding one of the more than one predefined ranking of the combination to indicate a specific ranking the UE prefers. The BS may send information indicating the specific ranking indicated by the UE is accepted or rejected by the BS. Optionally, if the BS rejected the specific rule indicated by the UE, the BS may indicate a new one from the more than one predefined ranking. UE should then use the ranking indicated by the BS.

If the ranking rule is configurable, BS may indicate a choice between which rule will be used. Once the ranking rule is indicated, additional indication may be needed for the specific ranking rule or the full ranking indication will be used as discussed below.

If the ranking is based on fixed special rules, as described in some examples, the following signaling may need to be sent from the BS to the UE. Based on the modulation first or layer first based rules described earlier: BS may perform one or more of:

1) Indicate a layer ranking information and use a fixed rule to derive joint modulation and layer ranking.

The layer ranking may be expressed as a layer ranking pattern, which can be simply the reliability ranking (from the highest to the lowest or vice versa) of each layer. The layer ranking pattern can be compressed using permutation pattern as there are limited number of choices, the permutation pattern can be simply a permutation of the L layers (Layer 1 to Layer L) . For example, for 4 layers, there are 24 permutation choices, which means, 5 bits (which can indicate 2⁵=32 choices) are enough rather than 8 (2×4=8) bits.

2) Indicate modulation order per layer.

a) Instead of indicating the full layer ranking information, BS may indicate just modulation scheme used for each layer. Then both BS and UE can use the rule of “a higher modulation order means a higher layer quality” to rank the layers based on a modulation order. In case of a same modulation order used for two or more layers or layer groups, the modulation order adopted for the two or more layer or layer groups can be defined based on a fixed rule (e.g. a lower layer index first) or can be indicated.

b) Indicate modulation order per layer and indicate a ranking for the layers that share the same modulation order. The ranking of the combination is based on the modulation order per layer and the ranking of two or more layers that share the same modulation order, or the ranking of the combination is based on the modulation order per layer and layer indexes corresponding to the same modulation order.

3) Ranking can be layer group based: a) Instead of indicating a ranking or a modulation order per layer, they can be indicated per layer group or a subset of layers: b) Group can be determined in advance: c) BS can indicate the number of layers belong to a layer group or how many layer groups are determined based on all the layers.

Table 3: Layer ranking indication

From the table 3, a value of LR (i) represents a location of the layer i in the ranking of all the L layers, i is a positive integer, i≤L, L is the total number of the layers mapped to one codeword (or i is an integer satisfying 0≤i≤ L-1 if the layer index starts from 0 instead of 1) . For example, when 0≤i≤L-1, the layer ranking indication indicates a ranking of 4 layers. The location of a layer corresponding to a layer index “0” is “3” in the ranking of all the 4 layers (which may mean the lowest channel quality or lowest priority among the 4 layers) , and the location of a layer corresponding to a layer index “1” is “0” in the ranking of all the 4 layers (which may mean the highest channel quality or highest priority among the 4 layers) , etc.

Table 4 illustrates an example of modulation order per layer indication and a ranking of more than one layer using (or corresponding to) the same modulation order.

Table 4: Modulation order per layer and ranking

It can be seen from the table 4, there are 4 layers corresponding to layer indexes of 0, 1, 2, 3, respectively. The modulation orders for the 4 layers are 4, 6, 4, 2, respectively, where the layer 0 and the layer 2 uses the same modulation order, that is 4. Therefore, there is additional information used to indicate the ranking of the layers using the same modulation order. The additional information may be one of possible implementations of the fist information. In this example, there are two layers uses the same modulation order, the addition information is used to indicate the ranking of the layer 0 and the layer 2. Specifically, priority of the layer 0 is lower than priority of the layer 2. Therefore, the ranking of the 4 layers can be determined based on information provided by table 4 as: L₁>L₂>L₀>L₃.

In general, the ranking may indicate an order of reliability on the combination of layer index and bit location index. An example of the ranking table is indicated as follows:

1) Table indicates the reliability ranking of the combination of a layer index and a bit location index;

2) Table can also be used to indicate fixed rule or configurable rule. For example, table 4 is used to indicate a fixed rule of “a higher modulation order of a layer means a higher priority of the layer” . The rule of “a higher modulation order of a layer means a higher priority of the layer” can be referred to as a third rule, which is used jointly with the first information to determine a ranking of the transmission layers, and further with a preconfigured ranking rule such as the rule 1 or the rule 2 in the above embodiments together can determine the ranking of the combination.

If the ranking for specific layer and bit index combination is fixed based on a certain rule, then the table for the ranking may be available to both BS and UE. If the ranking is configured by the BS, BS may indicate the ranking table. For example, a bit map can be used to indicate the ranking of the combination, where each set of bits is used to indicate its reliability ranking (that is, the ranking of the combination) and the location of the set of bits can indicate the combination of layer index and bit location among modulation symbols. For example, if the reliability ranking from table 5 is used, each number in the ranking column is indicating a ranking of a combination of layer index and bit location index. The ranking can be indicated using 4 bits, representing a choice of a number between 0 and 15. For example, number 0 represents the highest reliability or the highest priority, number 1 represents the second highest reliably or priority, …, and the number 15 represents the lowest reliability or priority. To indicate Table 5, a bit map consists 16 set of bits with each set consists of 4 bits can be used to indicate the ranking numbers in the ranking column. Each set of 4 bits corresponding to the ranking in one of the rows in the table, corresponding to the ranking of a combination of layer index and bit location index in the table. The location of the set of bits corresponds to the combination of layer index and bit location index in the table (i.e., which row of the table) . The bit map may consist of 16 sets of bits from a set of 0000 to a set of 1111 can be used. For example, the first set of the 16 sets indicates a ranking number 0 (i.e., 0000) of a combination of layer index 0 and a bit location index 0. The second set of the 16 sets indicates a ranking number 1 (i.e., 0001) of a combination of layer index 0 and a bit location index 1. The third set of the 16 sets indicates a ranking number 8 (i.e., 1000) of a combination of a layer index 0 and a bit location index 2, …, and so on. The last set of the 16 sets indicates a ranking number 7 (i.e., 0111) of a combination of a layer index 3 and a bit location 1, etc.

The full ranking indication can be further compressed based on permutation pattern. For example, the ranking of each combination of a layer index and a bit location can be 0-15 or 16 choices that can be indicated by 4 bits. The overall indication can be 64 (4×16=64 combinations) bits. However, the possible ranking is a permutation of number 0-15 (each number between 0-15 represents a combination of layer index and bit location index) which the overall choice is far less than 64 bit indications, so we can directly indicate possible choices among all permutation patterns. In this implementation, the BS transmit first information indicating a value corresponding to a first permutation pattern, the first permutation pattern corresponds to a first ranking of the combination, and the first permutation pattern is one of multiple permutation patterns that correspond to multiple rankings of the combination in a one-to-one relationship.

Table 5: Reliability ranking table based on indexes of layers and bit location

It can be seen from table 5, the ranking is based on a layer index and a bit location index. For example, a combination of layer index 0 and bit location index 0 corresponds to a location 0 in the ranking of the combination, which is the highest priority in the ranking of the combination. The combination of layer index 0 and bit location index 3 corresponds to a location 9 in the ranking of the combination, etc.

The indication of ranking can be further compressed based on grouping of either layers or bit locations or both. Group can be determined in advance. BS can indicate the number of layers belong to a layer group, and layers in the same layer group has same ranking or the same priority in the ranking. Similarly, the bit location can be grouped as the consecutive two bits (1^st, 2^nd or 3^rd 4^th has the same reliability) . The grouping can reduce overall signaling overhead as well as simplify mapping procedure. For example, if 2 layers are grouped together, the 4 layers become 2 layer groups. Further, if every 2 bits of a modulation symbol are grouped together, for a 4 layer with a fixed 16QAM modulation, there are now 2×2=4 reliability groups (which is 4 tiers equivalently) rather than 16 reliability groups without grouping. Then only the ranking for the 4 reliability groups or tier needs to be indicated.

In some scenarios, instead of indicating a ranking of reliability (as the reliability ranking or the ranking of the combination described in above embodiments) , BS may indicate directly how the ranking of the reliability is used for the mapping. For example, BS may indicate a subblock interleaver pattern associated with the ranking of the combination, that may be used for subblock interleaving process for the joint CW to QAM and layer mapping. Similarly, if the reverse function of f (i) , i.e., g (i) is used as described earlier, g (i) may be indicated instead of f (i) .

Table 6: Subblock interleaver pattern f (i)

If the ranking is fixed for a fixed number of layers, the table can be used to indicate a specific ranking that is known by both the BS and the UE. If the ranking is flexible, BS may indicate the f (i) values in DCI or a combination of RRC and DCI.

The ranking or subblock interleaving pattern can be simplified knowing the 2 adjacent bits (the 1st, the 2nd for example) have same reliability. Pattern can be compressed based on potential choices of f (i) as f (i) is a permutation from 0 to P-1.

Subblock interleaver pattern can be compressed based on layer grouping and bit location grouping following one or more of:

1) Group can be determined in advance;

2) BS can indicate the number of layers belonging to a layer group;

3) Similarly, the bit location can be grouped as the consecutive two bits (the1^st and the 2^nd, or the 3^rd and the 4^th) that have the same reliability.

The grouping can reduce overall signaling overhead as well as simplify mapping procedure.

The following are clarification about how to use the ranking information to implement the CW to QAM and layer mapping. To summarize, it is based on link between the ranking and the subblock interleaving pattern.

1) Once the ranking of the combination is determined based on the indication, the following example method can be used to determine a subblock interleaver pattern to implement the mapping procedure;

2) Define a new index (e.g. a tier index i) as a function of layer index l and bit location index j (the equation below assumes that both the layer index and the bit location start at 0, without loss of generality, indexes based on layer index and bit location index starting at 1 or other numbers can be easily derived) :

In this equation, l, represents a layer index, varies in a range of 0 to L-1, and j, represents a bit location, varies from 0 to m_l-1 for layer l, where m_l-1 is the modulation order adopted at the layer l. Therefore, a tier corresponding to a tier index i is a combination of layer l and bit location j associated with the modulation order corresponding to the layer l. The l , j and i are integers. The notation x is an index used for summation. The above equation should be i=function (l, j) , that is, the tier index i is a function with variables of l and j.

3) Subblock interleaver pattern f (i) represents the ranking of tier i among all tiers, where tier i is a combination of layer index and bit location index, i.e., f (i) is the location of the tier i in the ranking

If we rank the reliability of tier i from the most reliable tier to the least reliable tier, then the subblock interleaver pattern f (i) represents the ranking of tier i among all tiers, i.e., f (i) is the location of the tier i in the ranking. More specifically, if the reliability ranking is given by R (i₀) ≥R (i₁) ≥R (i₂) …≥ R (i_P-1) , where (i₀, …i_P-1) are a sequence of the tier index ranked from the highest to the lowest. R (i) is a tier reliability function for the ranking purpose, which can be defined as specific functions but it may not be defined in some scenarios as long as the tier ranking, represented by the tier ranking sequence (i₀, …i_P-1) , can be obtained. Then subblock interleaver pattern f (i) is given by f (i_k) =k for 0≤k≤P-1, i.e., f (i) is the location of the tier i in the tier ranking sequence.

In the above embodiments, the ranking of the combination is determined based on per layer and per bit location. In some other embodiments, instead of ranking on per layer and per modulation bit (i.e., per bit location of the modulation symbol) basis, the ranking can be determined based on per layer group or a subset of layers as well as per bit location group basis. Grouping can be done on layers as well as bit locations of the modulation symbols. Grouping can work together with any of the ranking determinations or ranking rules.

For example, there are L layers mapped to one codeword, the L layers may be grouped into several layer groups, for example, Q layer groups. The grouping can be determined based on difference in layer channel qualities. For example, layers with similar channel qualities may be grouped together, or layers with channel quality difference not exceeding a threshold may be grouped together.

The grouping can also be determined based on physical channels. For example, the two polarization of the antenna elements belong to the same group. In another example, each panel/beam belongs to a single layer group. In another example, transmission layer using different TRP belongs to different group, different layers of the same TRP belongs to the same group, etc.

A grouping method can be preconfigured, e.g., every L_g-layer belong to a layer group, the number of layers L_g belong to a layer group can be configured or fixed (e.g. L_g =2) . That is, L_g is a layer group size. The configuration of the number of layers belonging to a group can be in semi-static configuration (e.g. RRC signaling) , dynamic signaling (e.g. in DCI) or a combination of both (e.g. a combination of both RRC and DCI) . In some scenarios, instead of configuring or fixing the number of layers belonging to the same group, the maximum number of layer groups belonging to one CW or belonging to one MIMO transmission may be configured or fixed.

If multiple layers are grouped together, layers within a layer group can be assumed to have the same ranking. In another word, priorities of the layers within one transmission layer group are the same in the ranking. Similarly, the bit locations also can be grouped as the consecutive two bits (for example, the 1^st and the 2^nd, or the 3^rd and the 4^th, etc. ) of the modulation symbol have the same reliability.

Once multiple layers or multiple information bit locations are grouped together, the ranking rule only need to consider the ranking between layer groups or the ranking of a combination of layer groups and bit location groups (for example, we may regard a single layer as a special layer group that includes only one layer and/or a single bit location as a special bit location group that includes only one bit location, i.e., the number of components in the layer group or the bit location group is 1) . Once the group-based ranking is determined, ranking among layers in the same layer group or bit locations within the bit group can follow specific rules, e.g., ascending or descending order of the layer index or bit location index within the group. In this special case (which refers to the case where the single layer being a layer group or the single bit location being a bit group) , the number of the tiers remains the same asirregardless of grouping process, i.e., the mapping process does not change once the ranking is determined irregardless of grouping process.

In some other scenarios, group-based ranking also changes the number of the tiers and the mapping process. The examples are described as follows.

FIG. 15 shows an example of modulation as well as reliability ranking based on layer groups rather than a single layer. In the example, the CW is mapped to 4 layers but the transmission layers are grouped into two layer groups, (L1, L2) belongs to Layer Group (LG) 1 with 16QAM modulation (which corresponds to a modulation order=4) and (L3, L4) belongs to Layer Group (LG) 2 with QPSK modulation (which corresponds to a modulation order=2) . The joint modulation and layer ranking is based on layer groups with LG1, b₁b₂ > LG2, b₁b₂ > LG1, b₃b₄ with a total of 6 reliability tiers as shown in FIG. 15. Note that, since the L1 and L2 belong to one layer group, L3 and L4 belong to another layer group, a combination of each bit location and a layer group is one tier. For example, a combination of the 1st bit location of modulation symbols and LG1 is notated with LG1, b₁, and a combination of the 3rd bit location of modulation symbols and LG1 is notated with LG1, b₃. etc. Therefore, the 6 reliability tiers are illustrated as: (LG1, b₁) , (LG1, b₂) , (LG2, b₁) , (LG2, b₂) , (LG1, b₃) , (LG1, b₄) . Moreover, in FIG. 15, tiers corresponding one layer group and two consecutive bit locations are notated together for simplification. For example, (LG1, b₁) and (LG1, b₂) are notated together with (LG1, b₁b₂) , i.e., (L₁L₂) b₁b₂ illustrated in FIG. 15. The other notations illustrated in FIG. 15 are similar with what is clarified as examples, which will not be repeated for the sake of brevity. In the bit interleaving process, two bits instead of one bit are taken from each tier to write out horizontally to be prepared for two modulation symbols for each layer group tier. In the modulation process, two modulation symbols are produced for each layer group as well and mapped to the two layers in the layer group in order. The rest of the procedure is similar to the scheme where each layer group has 1 layer.

In the above embodiment shown in FIG. 15, the 2 bits (e.g. b₁ and b₂, b₃ and b₄) with the same reliability in a modulation symbol are still considered as 2 tiers for reliability ranking and mapping procedure. However, since the 2 bits have same reliability, in some scenario, the 2 bits can be grouped together as 1 tier. That is, each two consecutive bits in a modulation symbol are taken as a bit location group, which is called a bit group for simplification in the embodiments. In this scenario, the total number of tiers or subblocks/vertical sequences may be divided by 2 asWhen performs the joint modulation and layer mapping, 2 bits are selected from each tier/subblock/vertical sequence instead of 1. This will create similar results with potential lower complexity for bit interleaving process.

In above embodiments, indexes such as the tier index, the transmission layer index, the transmission layer groups index, bit location index, and so on, starts from 0 in some embodiments while starts from 1 in some other embodiments. The skilled person can deduce the corresponding expressions or descriptions with the indexes starting from 1 based on the descriptions with index starting from 0, and vice versa. For example, a notation b (i) and a notation b_i is equivalent, e.g., notations b (1) and b (2) and notations b₁ and b₂ are used to represent the same thing, respectively. Similarly, L1 is the same as L_j where j=1 in a math form. The index in some above embodiments may start from 1, however, it usually starts from 0 in communication standards. For the person skilled in the art, it is easy to deduce a corresponding expression in which index starts from 0 based on an expression in which the index starts from 1. The expressions in which index starts from 1 and the expressions in which index starts from 0 are equivalent without loss of generality etc.

FIG. 16 shows an example of grouping two modulation bits that have the same priority in the same reliability tier. The other parameter setting is the same as the example in FIG. 10. Now because of the grouping, instead of having P=16 tiers, there are P=8 tiers. The order of the 8 tiers, from the highest reliability (or priority) to the lowest reliability (or priority) , is represented as tier ranking 1, tier ranking 2, …, tier ranking 8, and each tier has twice the number of bits as the non-grouping case for the bit locations. Note that, the tier ranking 1 refers to the first location in the order of the 8 tiers which has the highest reliability, and the tier ranking 2 refers to the second location in the order of the 8 tiers which has the second highest reliability, and so on. In the bit interleaving process, two bits are taken from each tier to write horizontally to produce the bit stream for modulations. The rest of the procedure is similar to the case without grouping.

The advantages of the indication scheme in the above embodiments proposed by the present application may be summarized as follows:

1) Special ranking rule indication: a) minimum signaling overhead (because just layer ranking or modulation order itself needs to be indicated by a signaling) ; b) Capture majority of the gain;

2) Ranking table or subblock interleaver pattern: a) most flexible and accurate; b) Capture maximum gain;

3) Configurable ranking rules: tradeoff between full flexibility and the signaling overhead;

4) Layer grouping and/or bit location grouping and compression: further reduce overhead.

The methods according to embodiments of the present application are described in detail with reference to FIGS. 6-18. The apparatuses provided in embodiments of this application are described below in detail with reference to FIGS. 19-20. The description of apparatus embodiments corresponds to the description of the method embodiments. Therefore, for content that is not described in detail, please refer to the foregoing method embodiments. The details are not repeated herein for brevity.

Referring to FIG. 17, a schematic block diagram of an apparatus 10 according to some embodiments of the present application is illustrated. The apparatus 10 has a function of implementing the method descried in the above method embodiments. The apparatus 10 may include corresponding modules or units configured to implement method and/or embodiments descried above. In some implementations, the apparatus 19 includes a processing module 1001 and a communication module 1002. Optionally, the apparatus 10 may further include a storage module configured to store computer program code (or instructions) and/or data.

In some embodiments, the apparatus 10 may be a base station side apparatus, for example, a base station or a module in a base station, or a circuit or a chip responsible for a communication function in the base station. In some implementations, the processing module 1001 may be a processor (may include a scheduler) . The communication module 1002 may be a transmitting unit and/or a receiving unit. The transmitting unit and/or the receiving unit may be transmitter and/or receiver respectively, and the storage module may be a memory.

In some embodiments, the apparatus 10 may be a terminal side apparatus, for example, an ED or a module in an ED, or a circuit or a chip responsible for a communication function in an ED. In some implementations, the processing module 1001 may be a processor. The communication module 1002 may be a transmitting unit and/or a receiving unit. The transmitting unit and/or the receiving unit may be transmitter and/or receiver respectively, and the storage module may be a memory.

In some implementations, when the apparatus 10 is an ED or a module in an ED or the apparatus 10 is a network device or a module in a network device, a function of the apparatus 10 may be implemented by one or more processors. Specifically, the processor may include a modem chip, or a system on chip SoC chip or a SIP chip that includes a modem core. A function of the communication module 1002 may be implemented by a transceiver circuit.

In some implementations, when the apparatus 10 is a circuit or a chip that is responsible for a communication function in an ED or a network device, for example, a modem chip, a system on chip SoC chip or a SIP chip that includes a modem core, a function of the processing module 1001 may be implemented by a circuit system that is in the chip and that includes one or more processors or processor cores. A function of the communication module 1002 may be implemented by an interface circuit or a data transceiver circuit on the foregoing chip.

Referring to FIG. 18, a schematic block diagram of an apparatus according to some embodiments of the present application is illustrated. The apparatus 20 includes at least one processor 21. The at least one processor 21 is coupled to at least one memory 22. The at least one memory 22 is configured to store one or more instructions and/or executable computer code. The at least one processor 21 is configured to invoke the one or more instructions and/or executable computer code, so that the apparatus 20 implements the method provided in the embodiments of the present application. Optionally, the apparatus 20 may further include the at least one memory 22. Optionally, the apparatus 20 may further include at least one communication interface 23, and the at least one communication interface 23 is configured to input and/or output information or data to assist the at least one processor 21 to implement the method or embodiments described above.

In an implementation, the apparatus 20 may be any one of the communication devices in the method embodiments. For example, the apparatus 20 may be a network device or a terminal device.

An embodiment of the present application further provides a communication system comprising at least one of an apparatus in (or at) a UE of this application, or an apparatus in (or at) a network device of this application.

An embodiment of the present application further provides a method performed by a system comprising at least one of an apparatus in (or at) a UE of this application, and an apparatus in (or at) a network device of this application.

An embodiment of the present application further provides a computer-readable storage medium. The computer-readable storage medium stores computer-readable instructions, and when a computer reads and executes the computer-readable instructions, the computer is enabled to perform the method in any one of embodiments described above.

An embodiment of the present application further provides a computer program product. When a computer reads and executes the computer program product, the computer is enabled to perform the method in any one of embodiments described above.

It would be understood by a person skilled in the art that, for the purpose of convenience and brevity, in a detailed working process of the foregoing system, apparatus, and unit, reference may be made to a corresponding process in the foregoing method embodiments, and details are not described herein again.

It may be understood that the modules in the apparatus 10 may be logical or functional. Each function may correspond to one functional module, or two or more functions may be integrated into one functional module. In actual implementation, all or some of the modules may be integrated into one physical entity, or may be distributed in different physical entities. In addition, the foregoing functional modules may be implemented in a form of hardware, may be implemented in a form of software, or may be implemented in a form of a combination of hardware and software. Whether a function is performed in a form of hardware or software depends on particular applications and design constraint conditions of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application.

In an example, a functional module in any one of the foregoing apparatuses may be configured as one or more integrated circuits for implementing the methods disclosed herein, for example, one or more application-specific integrated circuits (application-specific integrated circuits, ASICs) , one or more central processing units (central processing units, CPUs) , one or more microprocessors (microcontroller units, MCUs) , one or more digital signal processors (digital signal processors, DSP) , one or more field programmable gate arrays (field programmable gate arrays, FPGAs) , or a combination of at least two of these integrated circuit forms.

In an example, the storage module may include a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an electrically erasable programmable memory, and/or a register.

A processor, a processor system, an application processor, a baseband processor, a processor circuit, or a processor core may be collectively referred to as a processor. The processor may include one or a combination of a central processing unit (CPU) , a digital signal processor (DSP) , a microprocessor (microprocessor unit, MPU) , a microcontroller (microcontroller unit, MCU) , a graphics processing unit (GPU) , a field programmable gate array (FPGA) , an artificial intelligence processor (AI processor) , or a neural network processing unit (NPU) .

Memory or a storage module may include one or more of the following storage media: a random access memory (RAM) , a static random access memory (static RAM, SRAM) , a dynamic random access memory (dynamic RAM, DRAM) , a phase-change memory (PCM) , a resistive random access memory (resistive RAM, ReRAM) , a magnetoresistive random access memory (magnetoresistive RAM, MRAM) , a ferroelectric random access memory (ferroelectric RAM, FRAM) , a cache, a register, a read-only memory (ROM) , a flash memory (flash memory) , an erasable programmable read-only memory (erasable programmable ROM, EPROM) , a hard disk, and the like. In an example, computer program instructions used to execute embodiments may be stored in a non-volatile memory, for example, at least a part of a memory or storage unit (for example, one or more of a ROM, a flash memory, an EPROM, or a hard disk) . When a terminal runs, a part or all of corresponding computer program instructions may be loaded to a memory that has a higher transmission speed with the processor, for example, at least a part of a memory or a storage unit (for example, one or more of a RAM, an SRAM, a DRAM, a PCM, a RERAM, an MRAM, a FRAM, a cache, or a register) , so that the processor executes the computer program instructions to perform the steps in the method embodiments disclosed herein.

In the disclosure, the word “a” or “an” when used in conjunction with the term “comprising” or “including” in the claims and/or the specification may mean “one” , but it is also consistent with the meaning of “one or more” , “at least one” , and “one or more than one” unless the content clearly dictates otherwise. Similarly, the word “another” may mean at least a second or more unless the content clearly dictates otherwise.

In the embodiments of this application, “and/or” describes an association relationship between associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. The character “/” generally indicates an “or” relationship between the associated objects. “At least one” means one or more. “At least one of A and B” , similar to “A and/or B” , describes an association relationship between associated objects and represents that three relationships may exist. For example, at least one of A and B may represent the following three cases: Only A exists, both A and B exist, and only B exists.

In the several embodiments provided in this application, the disclosed system, apparatus, and method may be implemented in other manners. For example, the described apparatus embodiment is merely an example. For example, the unit division is a logical function division and other methods of division may be used in an actual embodiment. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented using various communication interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms.

In addition, function units (or function modules) in the embodiments of this application may be integrated into one processing unit, each of the units may exist alone physically, or two or more units may be integrated into one unit.

When the functions are implemented in the form of a software functional unit and sold or used as an independent product, the functions may be stored in a computer-readable storage medium. The technical solutions of this application may be implemented in the form of a software product. The software product is stored in a storage medium, and includes several instructions for instructing a computer device (which may be a personal computer, a server, a network device, or the like) to perform all or some of the steps of the methods described in the embodiments of this application. The foregoing storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, a ROM, a RAM, a magnetic disk, an optical disc or the like.

The units described as separate parts may be or may not be physically separate, and parts displayed as units may be or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments. In addition, functional units in the embodiments of this application may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units are integrated into one unit.

The present disclosure encompasses various embodiments, including not only method embodiments, but also other embodiments such as apparatus embodiments and embodiments related to non-transitory computer readable storage media. Embodiments may incorporate, individually or in combinations, the features disclosed herein.

Although this disclosure refers to illustrative embodiments, this is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the disclosure, will be apparent to persons skilled in the art upon reference to the description.

Features disclosed herein in the context of any particular embodiments may also or instead be implemented in other embodiments. Method embodiments, for example, may also or instead be implemented in apparatus, system, and/or computer program product embodiments. In addition, although embodiments are described primarily in the context of methods and apparatus, other implementations are also contemplated, as instructions stored on one or more non-transitory computer-readable media, for example. Such media could store programming or instructions to perform any of various methods consistent with the present disclosure.

The foregoing description is merely a specific implementation of this application, but is not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims and the specification.

Claims

A method for communications comprising:

mapping, based on mapping information, a coded bit sequence including a plurality of coded bits to modulation symbols and L transmission layers, wherein the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol, L is an integer greater than one; and

transmitting first information used for determining the mapping information.
The method according to claim 1, wherein the L transmission layers are mapped to one codeword.
The method according to claim 1 or 2, wherein the first information indicates a ranking of the combination.
The method according to claim 1 or 2, wherein the first information indicates a value corresponding to a first permutation pattern, the first permutation pattern corresponds to a first ranking of the combination, and the first permutation pattern is one of multiple permutation patterns that correspond to multiple rankings of the combination in a one-to-one relationship.
The method according to the claim 1 or 2, wherein the first information indicates a ranking of the L transmission layers.
The method according to claim 5, wherein the ranking of the L transmission layers and a preconfigured rule are used jointly to determine a ranking of the combination, and the mapping information is determined based on the ranking of the combination.
The method according to claim 1 or 2, wherein the first information indicates a ranking of more than one transmission layer group, each transmission layer group comprises one or more transmission layers of the L transmission layers, and each transmission layer is comprised in one transmission layer group.
The method according to claim 7, wherein the ranking of the more than one transmission layer group and a preconfigured rule are used jointly to determine a ranking of the combination, and the mapping information is determined based on the ranking of the combination.
The method according to claim 7 or 8, wherein the more than one transmission layer group is preconfigured.
The method according to any of claims 7 to 9, wherein the first information further comprises one or more of:

a quantity of transmission layers comprised in each transmission layer group;

a quantity of the more than one transmission layer groups.
The method according to claim 1 or 2, wherein the first information indicates modulation schemes for each of the L transmission layers or for each of transmission layer groups.
The method according to claim 11, wherein the first information, a preconfigured rule and a third rule are used jointly to determine a ranking of the combination, the third rule includes that a priority of a first transmission layer in the L transmission layers that adopts a modulation scheme corresponding to a higher modulation order is higher than a priority of a second transmission layer in the L transmission layers that adopts a modulation scheme corresponding to a lower modulation order, or the third rule includes that a priority of a firs transmission layer group in more than one transmission layer group that adopts a modulation scheme corresponding to a higher modulation order is higher than a priority of a second transmission layer group in more than one transmission layer group that adopts a modulation scheme corresponding to a lower modulation order; and the mapping information is determined based on the ranking of the combination.
The method according to claim 12, wherein the first information is further used for indicating a ranking of transmission layers adopting a same modulation scheme; or

the first information is further used for indicating a ranking of transmission layer groups adopting a same modulation scheme.
The method according to any one of claims 6, 8-10, 12 or 13, wherein the preconfigured rule comprises:

a first rule based on which priority of the bit location of the modulation symbol is higher than priority of the transmission layer; or

a second rule based on which priority of the transmission layer is higher than priority of the bit location of the modulation symbol.
The method according to claim 14, wherein the method further comprises:

transmitting second information, wherein the second information is used for indicating the first rule or the second rule.
The method according to claim 1 or 2, wherein the first information is used for indicating a subblock interleaving pattern f (i) associated with a ranking of the combination, the subblock interleaving pattern f (i) represent an ordering of a subblock i among all subblocks, the subblock i is a sub-sequence of a coded bit sequence to be mapped to a transmission layer and a bit location of a modulation symbol or to be mapped to a transmission layer group and a bit location of a modulation symbol.
The method according to claim 16, wherein the method further comprises:

mapping the coded bit sequence to modulation symbols and the L transmission layers based on the subblock interleaving pattern.
The method according to claim 16 or 17, wherein the subblock interleaving pattern denoted with f (i) indicates a location of a first combination with an index i in the ranking of all combinations, i is an integer; and

the first combination comprises any one of:

a combination of a bit location of a modulation symbol and a transmission layer;

a combination of a bit location group of a modulation symbol and a transmission layer;

a combination of a bit location of a modulation symbol and a transmission layer group;

a combination of a bit location group pf a modulation symbol and a transmission layer group.
The method according to claim 18, wherein the bit location group comprises every two adjacent bit locations with the same priority in a modulation symbol.
The method according to any one of claims 1 to 19, wherein the ranking of the combination comprises a ranking of the combination in reliability.
A method for communications, implemented by a second apparatus, comprising:

receiving first information, wherein the first information is used for determining mapping information, the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol; and

demodulating, based on the mapping information, a signal transmitted via L transmission layers, L is an integer greater than one.
The method according to claim 21, wherein the L transmission layers are mapped to one codeword.
The method according to claim 21 or 22, wherein the first information indicates a ranking of the combination.
The method according to claim 21 or 22, wherein the first information indicates a value corresponding to a first permutation pattern, the first permutation pattern corresponds to a first ranking of the combination, and the first permutation pattern is one of multiple permutation patterns that correspond to multiple rankings of the combination in a one-to-one relationship.
The method according to the claim 21 or 22, wherein the first information indicates a ranking of the L transmission layers.
The method according to claim 25, wherein the ranking of the L transmission layers and a preconfigured rule are used jointly to determine a ranking of the combination, and the mapping information is determined based on the ranking of the combination.
The method according to claim 21 or 22, wherein the first information indicates a ranking of more than one transmission layer groups, wherein each transmission layer group comprises one or more transmission layers in the L transmission layers, and each transmission layer is comprised in one transmission layer group.
The method according to claim 27, wherein the ranking of the more than one transmission layer group and a preconfigured rule are used jointly to determine a ranking of the combination, and the mapping information is determined based on the ranking of the combination.
The method according to claim 21 or 22, wherein the first information indicates modulation schemes for each of the L transmission layers or for each of transmission layer groups.
The method according to claim 29, wherein the first information, a preconfigured rule and a third rule are used jointly to determine a ranking of the combination, the third rule includes that a priority of a first transmission layer in the L transmission layers that adopts a modulation scheme corresponding to a higher modulation order is higher than a priority of a second transmission layer in the L transmission layers that adopts a modulation scheme corresponding to a lower modulation order, or the third rule includes that a priority of a firs transmission layer group in more than one transmission layer group that adopts a modulation scheme corresponding to a higher modulation order is higher than a priority of a second transmission layer group in more than one transmission layer group that adopts a modulation scheme corresponding to a lower modulation order; and the mapping information is determined based on the ranking of the combination.
The method according to claim 30, wherein the first information is used further for indicating a ranking of transmission layers adopting a same modulation scheme; or

the first information is used further for indicating a ranking of transmission layer groups adopting a same modulation scheme.
The method according to claim 21 or 22, wherein the first information is used for indicating a subblock interleaving pattern f (i) associated with a ranking of the combination, the subblock interleaving pattern f (i) represent an ordering of a subblock i among all subblocks, the subblock i is a sub-sequence of a coded bit sequence to be mapped to a transmission layer and a bit location of a modulation symbol or to be mapped to a transmission layer group and a bit location of a modulation symbol.
A communication apparatus, configured to perform the method according to any one of claims 1 to 16 or any one of claims 17 to 32.
The communication apparatus of claim 33, comprising:

a processing module, configured to map, based on mapping information, a coded bit sequence including a plurality of coded bits to modulation symbols and L transmission layers, wherein the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol, L is an integer greater than one; and

a communication module, configured to transmit first information used for determining the mapping information.
The communication apparatus of claim 33, comprising:

a communication module, configured to receive first information, wherein the first information is used for determining mapping information, the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol; and

a processing module, configured to demodulate, based on the mapping information, a signal transmitted via L transmission layers, L is an integer greater than one.
The communication apparatus of claim 33, comprising:

one or more processors, configured to map, based on mapping information, a coded bit sequence including a plurality of coded bits to modulation symbols and L transmission layers, wherein the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol, L is an integer greater than one; and

an interface circuit, configured to transmit first information used for determining the mapping information.
The communication apparatus of claim 33, comprising:

an interface circuit, configured to receive first information, wherein the first information is used for determining mapping information, the mapping information is associated with a combination of a transmission layer and a bit location of a modulation symbol; and

one or more processors, configured to demodulate, based on the mapping information, a signal transmitted via L transmission layers, L is an integer greater than one.
The communication apparatus of claim 36 or 37, wherein the interface circuit comprises one or more transceivers.
An apparatus comprising:

one or more processors; and

one or more memories storing instructions which, when executed by the one or more processors, cause the apparatus to perform the method of any one of claims 1 to 16 or any one of claims 17 to 32.
A communication system, wherein the communication system comprises a first communication apparatus configured to perform the method of any one of claims 1 to 16 and a second communication apparatus configured to perform the method of any one of claims 17 to 32.
A non-transitory computer-readable storage medium having instructions stored thereon which, when executed by an apparatus, cause the apparatus to perform the method of any one of claims 1 to 16 or any one of claims 17 to 32.
A computer program product storing instructions which, when executed, cause an apparatus to perform the method of any one of claims 1 to 16 or any one of claims 17 to 32.