HK1235183B - Apparatus and method for inter-band pairing of carriers for time division duplex transmit- and receive-switching and its application to multiplexing of different transmission time intervals - Google Patents

Description

Device and method for carrier band pairing for time division duplex transmission and reception switching and its application in multiplexing different transmission time intervals

Priority claim

This application claims priority to and the benefit of: Provisional Patent Application No. 62/000,454, filed on May 19, 2014, in the U.S. Patent and Trademark Office, entitled “Apparatus and Method for Inter-Band Pairing of Carriers for Time Division Duplex Transmit-and Receive-Switching and its Application to Multiplexing of Different Transmission Time Intervals”; Provisional Patent Application No. 62/000,443, filed on May 19, 2014, in the U.S. Patent and Trademark Office, entitled “Apparatus and Method for Synchronous Multiplexing and Multiple Access for Different Latency Targets Utilizing Thin Control”; and Provisional Patent Application No. 62/000,454, filed on May 19, 2014, in the U.S. Patent and Trademark Office, entitled “Apparatus and Method for Inter-Band Pairing of Carriers for Time Division Duplex Transmit-and Receive-Switching and its Application to Multiplexing of Different Transmission Time Intervals”. Intervals," the entire contents of which are incorporated herein by reference.

Technical Field

Generally speaking, aspects of the present disclosure relate to wireless communication systems, and more particularly, to pairing inter-band time division duplex (TDD) carriers to achieve full-duplex communication.

Background Art

Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, etc. Such networks, which are typically multiple-access networks, support communications for multiple users by sharing the available network resources.

Within these wireless networks, a wide variety of data services can be provided, including voice, video, and email. Recently, wireless communication networks are being used for an even wider range of services, including mission-critical applications such as remote surgery and remote control applications, where real-time feedback is essential. In these applications, very low latency is crucial to achieve suitably high quality of service. That is, the time it takes for information to be sent from a communication device and for a response to be received at the communication device can need to be extremely fast, on the order of milliseconds.

As the demand for mobile broadband access continues to increase, research and development continue to advance wireless technologies to not only meet the growing demand for mobile broadband access, but also to improve and enhance the user experience.

Summary of the Invention

The following is a brief summary of one or more aspects of the present disclosure to facilitate a basic understanding of such aspects. This summary is not intended to be a general review of all anticipated features of the disclosure, nor is it intended to identify key or important elements of all aspects of the disclosure, or to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to introduce some concepts of one or more aspects of the disclosure in a concise form, thereby serving as a prelude to the more detailed description provided later.

Various aspects of the present disclosure provide for pairing of inter-band carriers with time division duplex (TDD) carriers. If the paired frequency band is a frequency division duplex (FDD) band, the base station and mobile device can send and receive additional thin control channels on the FDD carrier to achieve full-duplex operation. If the paired frequency band is a TDD band, conjugate or inverse carriers can be used to achieve full-duplex or a close approximation thereof. With the introduction of paired channels and fast control channels, fast uplink/downlink switching can be efficiently and effectively achieved for TDD carriers.

In one aspect, the present disclosure provides methods, apparatus, and computer-readable media with code for implementing wireless communications using an algorithm for pairing inter-band carriers for time division duplex transmission and reception switching. Here, a slave entity may wirelessly communicate with a scheduling entity using a first transmission time interval (TTI) on a first carrier, the first carrier being a time division duplex (TDD) carrier. Furthermore, the slave entity may wirelessly communicate on a second carrier that is paired with the first carrier but spaced apart in frequency from the first carrier using a second TTI that is different from the first TTI and at least partially overlaps with the first TTI.

After reading the detailed description below, these and other aspects of the present invention will become more fully understood. For those of ordinary skill in the art, other aspects, features and embodiments of the present invention will become apparent upon reviewing the following specific, exemplary embodiment description of the present invention in conjunction with the accompanying drawings. Although the features of the present invention may be discussed with respect to the following specific embodiments and drawings, all embodiments of the present invention may include one or more of the advantageous features discussed herein. In other words, although one or more features may be discussed as having specific advantageous features, one or more of such features may also be used according to the various embodiments of the present invention discussed herein. By analogy, although the exemplary embodiments may be discussed below as device, system or method embodiments, it should be understood that such exemplary embodiments may be implemented with various devices, systems and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a block diagram conceptually illustrating an example of a scheduling entity communicating with one or more slave entities according to some embodiments.

2 is a block diagram illustrating an example of a hardware implementation for a scheduling entity employing a processing system according to some embodiments.

3 is a block diagram illustrating an example of a hardware implementation for a slave entity employing a processing system, according to some embodiments.

4 is a diagram illustrating a synchronous multiple access channel structure in a full-duplex system for multiplexing low-latency uplink data with regular uplink data according to an example.

5 is a diagram illustrating a synchronous multiple access channel structure having a time division duplex (TDD) carrier paired with a frequency division duplex (FDD) carrier to multiplex low latency uplink data with regular uplink data according to an example.

6 is a call flow diagram illustrating an example of multiplexing low-latency uplink data with regular uplink data using a thin control channel in accordance with some embodiments.

7 is a flow diagram illustrating an example of multiplexing low-latency uplink data with regular uplink data using a thin control channel from the perspective of a scheduling entity in accordance with some embodiments.

8 is a diagram illustrating a synchronous multiple access channel structure having a TDD carrier paired with an FDD carrier to multiplex low-latency uplink data with regular uplink data, according to an example.

9 is a call flow diagram illustrating an example of multiplexing low-latency downlink data with regular uplink data using a thin control channel in accordance with some embodiments.

10 is a flow diagram illustrating an example of multiplexing low-latency downlink data with regular uplink data using a thin control channel from the perspective of a scheduling entity in accordance with some embodiments.

11 is a diagram illustrating a synchronous multiple access channel structure having a TDD carrier paired with an FDD carrier to multiplex low-latency uplink data with regular downlink data, according to an example.

12 is a call flow diagram illustrating an example of multiplexing low-latency uplink data with regular downlink data using a thin control channel in accordance with some embodiments.

13 is a flow diagram illustrating an example of multiplexing low-latency uplink data with regular downlink data using a thin control channel from the perspective of a scheduling entity in accordance with some embodiments.

14 is a diagram illustrating inverse (conjugate) pairing of time division duplex carriers according to an example.

FIG15 is a diagram illustrating an inverse (conjugate) pairing of time division duplex carriers according to another example.

16 is a diagram illustrating a synchronous multiple access channel structure with paired TDD carriers to multiplex low-latency uplink data with regular uplink data according to an example.

17 is a call flow diagram illustrating an example of multiplexing low-latency uplink data with regular uplink data using a thin control channel in accordance with some embodiments.

18 is a flow diagram illustrating an example of multiplexing low-latency uplink data with regular uplink data using a thin control channel from the perspective of a scheduling entity in accordance with some embodiments.

19 is a diagram illustrating a synchronous multiple access channel structure with paired TDD carriers to multiplex low-latency downlink data with regular uplink data, according to an example.

20 is a call flow diagram illustrating an example of multiplexing low-latency downlink data with regular uplink data using a thin control channel in accordance with some embodiments.

21 is a flow diagram illustrating an example of multiplexing low-latency downlink data with regular uplink data using a thin control channel from the perspective of a scheduling entity in accordance with some embodiments.

22 is a diagram illustrating a synchronous multiple access channel structure with paired TDD carriers to multiplex low-latency uplink data with regular downlink data, according to an example.

23 is a call flow diagram illustrating an example of multiplexing low-latency uplink data with regular downlink data using a thin control channel in accordance with some embodiments.

24 is a flow diagram illustrating an example of multiplexing low-latency uplink data with regular downlink data using a thin control channel from the perspective of a scheduling entity in accordance with some embodiments.

25 is a flow diagram illustrating an example of wireless communication using a TDD carrier paired with a second carrier and multiplexing long TTIs with short TTIs in accordance with some embodiments.

26 is a flow diagram illustrating an example of wireless communications using a pair of TDD carriers for full-duplex communications in accordance with some embodiments.

DETAILED DESCRIPTION

The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configuration in which the concepts described herein may be practiced. The detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

The various concepts presented throughout this disclosure can be implemented in a wide variety of telecommunication systems, network architectures, and communication standards. For example, the Third Generation Partnership Project (3GPP) is a standards body that specifies several wireless communication standards for networks involving the Evolved Packet System (EPS), which are often referred to as Long Term Evolution (LTE) networks. LTE networks can provide end-to-end delays between transmitting and receiving devices on the order of 50 ms, given that the over-the-air delay for a particular packet is in the range of 10 ms. Currently known LTE functionality uses a 1 ms transmission time interval (TTI) to provide a round-trip time (RTT) of at least approximately 8 ms for certain feedback signaling (i.e., hybrid automatic repeat request (HARQ) signaling). (Here, TTI corresponds to the minimum duration of an information unit that can be decoded.) For time division duplex (TDD) LTE configurations, the uplink/downlink configuration has a relatively fixed configuration that takes approximately 10 ms to change. Typically, LTE provides a one-size-fits-all approach in which all services and packets rely on these same delay ranges.

Evolved versions of LTE networks, such as fifth-generation (5G) networks, can provide a variety of different types of services or applications, including but not limited to web browsing, video streaming, VoIP, mission-critical applications, multi-hop networks, remote operations with real-time feedback (e.g., remote surgery), and the like. These different service sets can benefit from having multiple latency targets that are significantly different from one another. However, the one-size-fits-all approach to LTE networks described above can make it difficult to multiplex services with different latency targets.

Spectral compatibility of systems supporting such different latency targets can be challenging. For example, time multiplexing of regular/low-latency services may violate the requirements of low-latency grouping. Furthermore, frequency domain resources reserved for low-latency services will limit peak rates and relay efficiency. Therefore, new approaches are needed for next-generation networks to support the ability to multiplex various types, categories, and types of services (including but not limited to services with extremely different latency characteristics).

According to some aspects of the present disclosure, apparatus, methods, and computer instructions are disclosed for providing pairing of inter-band carriers with time division duplex (TDD) carriers. If the paired frequency band is a frequency division duplex (FDD) band, the base station and mobile device can send and receive additional thin control channels on the FDD carrier to achieve full-duplex operation. If the paired frequency band is another TDD band, full-duplex communication can be achieved using conjugate or inverse carriers. With the introduction of paired channels and fast control channels, fast uplink/downlink switching can be efficiently and effectively achieved for TDD carriers to achieve multiplexing of various types, categories, and types of business and services.

Referring now to FIG. 1 , a block diagram is provided illustrating a scheduling entity 102 and multiple slave entities 104 engaging in wireless communications using thin control channels 108/112 and thin feedback channels 114 (described in further detail below). Of course, the channels illustrated in FIG. 1 are not necessarily all of the channels that may be used between the scheduling entity 102 and the slave entities 104, and one skilled in the art will recognize that other channels, such as other control channels and feedback channels, may be used in addition to those illustrated. As shown in FIG. 1 , the scheduling entity 102 may broadcast downlink data 106 to one or more slave entities 104. According to aspects of the present disclosure, the term downlink may refer to point-to-multipoint transmissions originating from the scheduling entity 102. Broadly speaking, the scheduling entity 102 is a node or device responsible for scheduling traffic in a wireless communication network, where the traffic includes downlink transmissions and, in some cases, uplink data 110 from one or more slave entities to the scheduling entity 102. (Another way to describe this approach may be to use the term broadcast channel multiplexing.) According to aspects of the present disclosure, the term uplink may refer to point-to-point transmissions originating from the slave entity 104. Broadly speaking, the slave entity 104 is a node or device that receives scheduling control information, including but not limited to scheduling grants, synchronization or timing information, or other control information from another entity (e.g., the scheduling entity 102) in the wireless communication network.

In further aspects of the present disclosure, the scheduling entity 102 can broadcast thin control channels 108 and/or 112 to one or more dependent entities 104. As described herein below, the use of thin control channels 108/112 can enable modification/puncturing of uplink and/or downlink data being sent using a first, long transmission time interval (TTI) with other data (e.g., low latency (LoLat) packets) of a second, short transmission time interval (TTI).

In addition, the slave entity 104 may send a thin feedback channel 114 to the scheduling entity 102. In some examples, the thin feedback channel may include a request to the scheduling entity to modify/puncture the first, long TTI using LoLat packets using a second, short TTI. Here, in response to the request sent on the thin feedback channel 114, the scheduling entity 102 may send information in the thin control channel 112, wherein the information may schedule the modification/puncturing of the long first TTI using LoLat packets using the second, short TTI.

2 is a conceptual diagram illustrating an example of a hardware implementation for a scheduling entity 102 employing a processing system 214. According to various aspects of the present disclosure, an element, or any portion of an element, or any combination of elements may be implemented using a processing system 214 including one or more processors 204.

In various aspects of the present disclosure, the apparatus 200 may be any suitable wireless transceiver apparatus, and in some examples, may be embodied by a base station (BS), a base transceiver station (BTS), a wireless base station, a wireless transceiver, a transceiver functional unit, a basic service set (BSS), an extended service set (ESS), an access point (AP), a node B, an evolved node B (eNB), a mesh node, a relay, or some other suitable terminology. Within this document, a base station may be referred to as a scheduling entity, which indicates that the base station provides scheduling information to one or more subordinate entities.

In other examples, the apparatus 200 may be embodied by a wireless user equipment (UE). Examples of UEs include cellular phones, smartphones, Session Initiation Protocol (SIP) phones, laptop computers, notebooks, netbooks, smartbooks, personal digital assistants (PDAs), satellite radios, global positioning system (GPS) devices, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, entertainment devices, vehicle components, wearable computing devices (e.g., smart watches, health or wellness trackers, etc.), instruments, sensors, vending machines, or any other device with similar functionality. Those skilled in the art may also refer to UEs as mobile stations (MS), subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals (ATs), mobile terminals, wireless terminals, remote terminals, handheld devices, terminals, user agents, mobile clients, clients, or some other appropriate terminology. Within this document, UEs may be referred to as scheduling entities, or subordinate entities. That is, in various aspects of the present disclosure, a wireless UE may act as a scheduling entity that provides scheduling information to one or more slave entities, or may act as a slave entity based on scheduling information provided by the scheduling entity.

Examples of the processor 204 include a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gated logic unit, a discrete hardware circuit, and other suitable hardware configured to perform the various functions described throughout the present disclosure. That is, the processor 204 as used in the apparatus 200 can be used to implement any one or more of the processes described below and in Figures 5-26.

In this example, processing system 214 may be implemented using a bus architecture, generally represented by bus 202. Depending on the specific application and overall design constraints of processing system 214, bus 202 may include any number of interconnecting buses and bridges. Bus 202 links various circuits including one or more processors (generally represented by processor 204), memory 205, and computer-readable media (generally represented by computer-readable media 206). Bus 202 may also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and are not described in any further detail. Bus interface 208 provides an interface between bus 202 and transceiver 210. Transceiver 210 provides a means for communicating with various other devices via a transmission medium. Depending on the nature of the device, a user interface 212 (e.g., a keyboard, display, speaker, microphone, joystick) may also be provided.

In some aspects of the present disclosure, processor 204 may include resource assignment and TTI control circuitry 241 configured to generate, schedule, and modify resource assignments or grants of time-frequency resources. Resource assignment and TTI control circuitry 241 may also be configured to determine the TTIs used for uplink and downlink transmissions, for example, whether data transmission should use a first, long TTI or a second, short TTI. Resource assignment and TTI control circuitry 241 may operate in coordination with resource assignment and TTI control software 251. Processor 204 may also include data and control channel generation and transmission circuitry 242 configured to generate and transmit uplink and downlink data and control channels, as well as uplink feedback channels and downlink control channels, including but not limited to a thin control channel, a thin feedback channel, a LoLat grant channel, a grant modification channel, and an assignment channel. Data and control channel generation and transmission circuitry 242 may operate in coordination with data and control channel generation and transmission software 252. The processor 204 may also include feedback receiving and processing circuitry 243 configured to receive a scheduling request on an uplink feedback channel, wherein the scheduling request is configured to request the grant of time-frequency resources for uplink user data transmission. The thin feedback receiving and processing circuitry 243 may operate in a collaborative manner with the thin feedback receiving and processing software 253. The processor 204 may also include data channel receiving and processing circuitry 244 configured to receive and process user data from one or more slave entities on an uplink data channel. The data channel receiving and processing circuitry 244 may operate in a collaborative manner with the data channel receiving and processing software 254. The processor 204 may also include TDD control circuitry 245 and FDD control circuitry 246, each configured to control wireless communications (e.g., transmission and/or reception of data and/or control channels) on one or more TDD or FDD carriers. The TDD control circuitry may operate in a collaborative manner with the TDD control software 255. The FDD control circuitry may operate in a collaborative manner with the FDD control software 256.

The processor 204 is responsible for managing the bus 202 and general processing, including executing software stored on the computer-readable medium 206. When executed by the processor 204, the software causes the processing system 214 to perform the various functions described below for any particular device. The computer-readable medium 206 can also be used to store data that is manipulated when the processor 204 executes the software.

One or more processors 204 in the processing system can execute software. Whether it is referred to as software, firmware, middleware, microcode, hardware description language or other terms, software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes, functions, etc. The software can be located on a computer-readable medium 206. The computer-readable medium 206 can be a non-transitory computer-readable medium. For example, non-transitory computer-readable media include magnetic storage devices (e.g., hard disks, floppy disks, tapes), optical disks (e.g., compact discs (CDs) or digital versatile discs (DVDs)), smart cards, flash memory devices (e.g., cards, sticks or key drives), random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, and any other suitable media for storing software and/or instructions that can be accessed and read by a computer. For example, computer-readable media may also include carrier waveforms, transmission lines, and any other suitable medium for transmitting software and/or instructions that can be accessed and read by a computer. Computer-readable media 206 may be located within processing system 214, external to processing system 214, or distributed across multiple entities including processing circuitry 214. Computer-readable media 206 may be embodied as a computer program product. For example, a computer program product may include a computer-readable medium in packaging material. Those skilled in the art will recognize how to best implement the functionality described throughout this disclosure depending on the specific application and the design constraints imposed on the overall system.

3 is a conceptual diagram illustrating an example of a hardware implementation for an exemplary slave entity 104 employing a processing system 314. According to various aspects of the present disclosure, an element, or any portion of an element, or any combination of elements, may be implemented utilizing a processing system 414 including one or more processors 304.

The processing system 314 can be substantially the same as the processing circuit 214 shown in FIG2 and can include a bus interface 308, a bus 302, a memory 305, a processor 304, and a computer-readable medium 306. The slave entity 304 can include a user interface 312 and a transceiver 310 (substantially similar to those described above in FIG2). The processor 304, as used in the slave entity 104, can be used to implement any one or more of the processes described below and in the processes shown in FIG5-26.

In some aspects of the present disclosure, processor 304 may include uplink transmission fast pause circuitry 341, configured to quickly pause uplink transmissions, for example, by driving a zero input to a power amplifier within transceiver 310, or, in another example, to quickly shut down the power amplifier within transceiver 310. Uplink transmission fast pause circuitry 341 may operate in coordination with uplink transmission fast pause software 351. Processor 304 may also include data and control channel generation and transmission circuitry 342, configured to generate and transmit uplink data on a data channel, and to generate and transmit uplink control information and feedback information on a control and feedback channel. Data and control channel generation and transmission circuitry 342 may operate in coordination with data and control channel generation and transmission software 352. Processor 304 may also include data and control channel reception and processing circuitry 343, configured to receive and process downlink data on a data channel, and to receive and process control information on one or more downlink control channels. In some examples, received downlink data and/or control information may be temporarily stored in a data buffer within memory 305. Data and control channel reception and processing circuitry 343 may operate in coordination with data and control channel reception and processing software 353. Processor 304 may also include TDD control circuitry 344 and FDD control circuitry 345, each configured to control wireless communications (e.g., transmission and/or reception of data and/or control channels) on one or more TDD or FDD carriers. The TDD control circuitry may operate in coordination with the TDD control software 354. The FDD control circuitry may operate in coordination with the FDD control software 355.

As described below, some aspects of the present disclosure provide wireless communications using a TDD carrier paired with a second carrier and multiplexing long TTIs and short TTIs on the paired carriers. Additional aspects of the present disclosure provide wireless communications using a pair of TDD carriers for full-duplex communications.

Of course, these examples are provided only to illustrate certain concepts of the present invention. Those skilled in the art will appreciate that these examples are merely exemplary in nature, and other examples may also fall within the scope of protection of this disclosure and the appended claims.

Thin control channel in full-duplex system

Some aspects of the present disclosure provide for synchronous multiplexing of services and traffic of different categories with different latency targets. For example, multiplexing can be achieved by using a certain "thin control channel" described below. Such a thin control channel can provide fast signaling to enable multiplexing of data with a short TTI with other data with a long TTI. For example, high priority, low latency (LoLat) data with a short TTI can be implemented to interrupt regular traffic with a long TTI. Figure 4 is a schematic diagram showing an example of a synchronous multiple access channel structure including a "thin" control channel, as can be implemented according to some aspects of the present disclosure. As shown in Figure 4, the channel structure is applicable to uplink data transmission, i.e., transmission from the slave entity 104 to the scheduling entity 102. Of course, the channel structure is not limited to such a scheme, but can be generally applied to any link where the receiving device schedules traffic.

In this view, the horizontal axis (t) represents time, and the vertical axis (f) represents frequency (not depicted to scale). The channel resources for each user of the air interface occupy a given area in the channel, as depicted in different blocks. For example, some time-frequency resources can be used by "conventional" users 402, and the "conventional" users 402 have less stringent delay requirements for their communications. In this view, for example, each user in the six conventional users 402 marked as users A, B, C, D, E and F is scheduled with the time-frequency resources indicated by the blocks of their corresponding marks. Of course, in each example, any number of users can be scheduled to use resources. In addition, although in this view, all time-frequency resources are shown as being assigned to conventional users, in each example, some or even all of these time-frequency resources may all be unassigned, or may be assigned for other purposes that are different from conventional user data.

In the context of the present disclosure, a regular user 402 may be a slave entity that receives a resource assignment from the scheduling entity 102, wherein the resource assignment instructs the slave entity 104 to use a long transmission time interval (TTI). Such regular users 402 may be more tolerant of delays in their communications and, in some examples, may be more optimized for capacity. Consequently, these users may use such longer TTIs for packets that can tolerate more delays, compared to other users that may require low-latency (LoLat) communications or other types of communications. A long TTI can broadly be any TTI that is longer than a short TTI (which will be described in further detail below). In some examples, a long TTI can be a TTI having a duration of multiple data symbols or time slots. Some non-limiting examples of a long TTI may have a duration of 100 μs, 240 μs, or 1 ms. Of course, any suitable duration may be used for a long TTI within the scope of the present disclosure.

Furthermore, as shown in FIG4 , in addition to the uplink data traffic channel used by regular users 402, a “thin” feedback channel 407 may also be used in the uplink direction as shown. Here, the thin feedback channel 407 may be the same as the thin feedback channel 114 described above and shown in FIG1 . Within the present disclosure, the thin feedback channel may be located in one or more frequency sub-bands outside (e.g., above) the frequency sub-bands used for uplink traffic transmission (e.g., the allocated time-frequency resources described above for regular users A-F 402). The width of the thin feedback channel 407 in the frequency direction may be reduced or minimized in order to reduce or minimize the amount of overhead used by the thin feedback channel 407.

In addition, as shown in Figure 4, in addition to the uplink traffic and feedback channels, a thin control channel 406 can also be used in the downlink direction as shown. Here, the thin control channel 406 can be the same as one or both of the thin control channels 108/112 described above and shown in Figure 1. In the present disclosure, the thin control channel can be located in one or more frequency sub-bands outside the frequency sub-bands used for uplink traffic and feedback transmission (e.g., the allocated time-frequency resources described above for conventional users A-F 402 and thin feedback channel 407). For example, in a frequency division duplex (FDD) system, the thin control channel 406 can be in a frequency band different from the uplink traffic and feedback channel. The width of the thin control channel 406 in the frequency direction can be reduced or minimized so as to reduce or minimize the amount of overhead used by the thin control channel 406. In further aspects, all active users (e.g., slave entities 104, including but not necessarily limited to regular users 402) in communication with the scheduling entity 102 broadcasting the thin control channel 406 can monitor (and in some examples, buffer) the thin control channel 406 shown herein.

As shown in Figure 4, each time slot, symbol or unit of the thin control channel 406 can correspond to the duration of a short TTI. That is, in some examples, the short TTI can correspond to the duration of a single symbol. Some non-limiting examples of the short TTI can have a duration of 10μs, 20μs, 100μs or any other suitable duration shorter than the long TTI. In some examples, the long TTI can represent an integer multiple of the short TTI. In some examples, a common symbol duration can be used in both the long TTI and the short TTI, or in other examples, different symbol durations can be used in the long TTI and the short TTI. The duration of the information symbols carried in either the long TTI or the short TTI can also be of any suitable duration, one example of which is that each symbol is 10μs in duration. In an example using orthogonal frequency division multiplexing, an additional 1μs cyclic prefix can be added to the symbol duration.

In one aspect of the present disclosure, such a thin control channel 406 can enable dynamic multiplexing of traffic for LoLat users 404 (which use short TTIs) and traffic for regular users 402 (which use long TTIs). That is, multiple regular users 402 can send uplink communications using existing assignments of time-frequency resources. Here, any suitable control channel (including but not necessarily limited to the thin control channel 406) can be used to grant resources to various entities in the network so that these slave entities 104 can use long TTIs to send uplink data according to their respective assignments.

Here, it may be the following situation: a slave entity in the network wishes to transmit LoLat data. Here, to maintain orthogonality between multiple slave entities, a central scheduling entity may be used to schedule uplink transmissions for each of these slave entities, and they may generally not randomly transmit uplink data without receiving assigned time-frequency resources for such transmissions. Therefore, when a slave entity determines that it has traffic (e.g., high-priority traffic) that it wishes to transmit with lower latency, the slave entity may transmit a LoLat scheduling request 409 on the thin feedback channel 407. The LoLat scheduling request 409 is shown as occupying a single short TTI, but this is not necessarily always the case, and various LoLat scheduling requests may occupy any appropriate number of short TTIs or symbol lengths. The content of the LoLat scheduling request 409 may include information about the LoLat data that the transmitting entity wishes to transmit, such as the length, data type, priority, latency, or any other appropriate information related to the LoLat data.

In response to the LoLat scheduling request 409, the recipient of the LoLat scheduling request 409 (e.g., a scheduling entity) may determine a grant scheduling adjustment accordingly. In this way, the scheduling entity may make resources available to the requesting slave entity for its LoLat transmission. Accordingly, the scheduling entity may send an uplink grant modification 408 to its regular user 402 on the thin control channel 406. The uplink grant modification 408 may inform the regular user 402 that their grant is being modified and that the previously allocated long TTI time-frequency resources will be punctured and will no longer be used by the regular user 402. Here, in some examples, puncturing the resources of the regular user 402 means that the regular user 402 stops transmitting during the time associated with the reassigned short TTI. In other examples, when one or more forms of channel multiplexing are used (including, but not limited to, frequency division multiplexing and code division multiplexing), puncturing the resources of regular user 402 may mean that regular user 402 ceases to use the punctured resources but may continue to transmit uplink data using another frequency or another scrambling code (different from the resources granted to LoLat user 404) to maintain orthogonality. As described above, thin control channel 406 may be a point-to-multipoint broadcast channel monitored by all subordinate entities communicating with the scheduling entity. In this manner, any user with previously granted time-frequency resources that were punctured by uplink grant modification 408 may be informed or instructed not to use the specific time-frequency resources now allocated to LoLat user 404 for their uplink transmissions.

In another aspect, uplink grant modification 408 may include not only grant modification information for regular user 402, but also, in some examples, grant information for requesting LoLat user 404, where the grant information indicates that the punctured time-frequency resource has been allocated to LoLat user 404. In another example within the scope of the present disclosure, the grant information for requesting LoLat user 404 may be carried on a separate uplink grant channel (not shown). That is, in some examples, the thin control channel may exclude the grant information for LoLat user 404, which is sent on any suitable downlink channel readable by requesting LoLat user 404. Regardless, the grant information for requesting LoLat user 404 may include information identifying LoLat user 404, information identifying one or more time-frequency resources, a modulation and coding scheme, a transmission scheme, or any other suitable information related to the resources granted to requesting LoLat user 404.

In the diagram of FIG10 , LoLat user 404 sends a LoLat scheduling request 409, but all dependent entities (including regular user 402) receive an uplink grant modification 408. Here, in another aspect of the present disclosure, regular users 402 can be configured so that they can decode the uplink grant modification 408 relatively quickly, so that they can quickly stop transmitting (e.g., puncture their transmissions) during the reallocated short TTI. In this way, these time-frequency resources can be quickly made available for LoLat user 404 to transmit its LoLat symbols.

The example shown in FIG4 applies to a full-duplex scheme, in which a downlink channel such as a thin control channel 406 can be used at the same time as an uplink channel such as an uplink data channel. In this scheme, because communication in both directions is initiated simultaneously, all active users can monitor (and in some examples, buffer) the thin control channel 406 shown herein. However, in a half-duplex scheme such as a time division duplex (TDD) channel structure, the multiplexing of data with different TTIs requires additional consideration.

Thin Control Channel in TDD System - Paired Carriers

Thin control channels, such as the thin control channel 406 described above, have been identified as features for implementation for a variety of potential uses. For example, by using thin control channels, low-latency data rate control, coordinated multi-point (CoMP) solutions, and improved access to unlicensed bands can be provided to communication systems. Of course, these are just some examples of features that can be implemented using thin control channels, and it will be understood by those skilled in the art that other features can also be implemented by way of thin control channels. A related feature provided by the use of thin control channels is opportunistic send/receive switching, wherein a thin control channel in one direction can be used to quickly modify data communications in another direction.

Time division duplex (TDD) is a well-known duplexing technology that provides two-way communication between devices, and it separates the signals in different directions from each other by applying time division multiplexing. For example, channel resources can be divided into some time slots, some of which are allocated for uplink transmission, and other are allocated for downlink transmission. In the TDD scheme, during any specific time slot in the TDD frequency band, only uplink transmission or downlink transmission can occur, and the two cannot occur simultaneously. A kind of defect of the TDD scheme is that it is only a half-duplex scheme, and this is because at any given moment, only one direction of communication can be carried out. Due to its half-duplex nature, during the process of ongoing transmission/reception, it is usually impossible to utilize fast control channels to carry out opportunistic transmission/reception switching (as above when introducing thin control channels, described in conjunction with Figure 4). That is, referring again to FIG. 4 , if a particular user (e.g., user D) is transmitting its uplink at the time uplink grant modification 408 is transmitted, that user will not receive the uplink grant modification 408 and, therefore, will not be informed of the grant modification, which prohibits puncturing its uplink transmission to make room for LoLat user 404.

An exception (where TDD alone may be sufficient) may be the case where resources with different TTIs are multiplexed on downlink communications (e.g., downlink/downlink multiplexing, where one downlink transmission of a first TTI may be interrupted by another downlink transmission of a second TTI), which may be achieved without full-duplex operation. That is, in this case, the transmissions of the thin control channel and the data channel will be in the same downlink direction, so that in one direction (or half-duplex) configuration, the transmitter continues to transmit and the receiver continues to receive.

Therefore, in order to provide improved functionality through thin control channels in cases of uplink/uplink multiplexing, downlink/uplink multiplexing, or uplink/downlink multiplexing, it is desirable to achieve full-duplex operation and functionality even on the TDD spectrum.

4, an example of thin control for uplink data (i.e., transmissions from a slave entity) includes bidirectional full-duplex communication, including regular user data 402 and a thin feedback channel 407 in the uplink direction, and a thin control channel 406 in the downlink direction. Here, it can be observed that the thin control channel 406 can be transmitted during each short TTI, and furthermore, if the transmitting device (e.g., a slave entity) wishes to interrupt and transmit LoLat data 404, then at the same time as one of the thin control channel transmissions in the downlink direction, the LoLat user 404 can transmit a LoLat scheduling request 409 in the uplink direction. (Also, the inserted LoLat packet can be a downlink packet, or any other variation of an interrupted uplink packet).

In a strict TDD system, this approach is not possible, as a device cannot autonomously utilize a transmission in one direction to interrupt transmission in the other direction (without informing the other side of the link). Similarly, if a UE is performing an uplink transmission, if it is a strict TDD system, the UE will not be aware of any attempts by the receiving device to modify its alignment, as it will not be able to receive anything on the downlink at all while it is transmitting uplink.

Therefore, according to some aspects of the present disclosure, a channel structure is provided that incorporates a pairing of a TDD carrier with a second carrier, wherein the TDD carrier and the second carrier may be in different frequency bands (inter-band carriers). When the paired carriers provide opposite, conjugate, or complementary communication directions compared to the TDD carrier, full-duplex communication can be achieved in at least some of the time slots by simultaneously using the uplink direction of communication in one carrier and the downlink direction of communication in the other carrier.

In some examples, the paired (second) carrier can be a frequency division duplex (FDD) band capable of full-duplex communication. That is, if the paired carrier is an FDD carrier, the paired carrier can include multiple carriers, such as an uplink component carrier and a downlink component carrier. Therefore, if the paired carrier is in an FDD band, both ends of the link (scheduling and slave) can simultaneously send and receive thin control channels on the FDD carrier.

In other examples, the paired carriers may be in a TDD frequency band. In this case, in one aspect of the present disclosure, two paired TDD carriers may be conjugated or inverse duplexed to achieve full duplexing. This conjugated duplexing is typically established during some or all of the time slots or frames of one of the carriers, and when those frames are configured for communication in one direction, the corresponding time slots or frames in the paired carriers are configured for communication in the other direction at the same time. In this way, by implementing paired carriers and fast (thin) control channels, fast uplink/downlink switching and multiplexing can be achieved for TDD carriers in an efficient and effective manner, among other functions.

Downlink/downlink multiplexing

In one aspect of the present disclosure, the downlink/downlink multiplexing described above for data sent on a TDD carrier (e.g., to achieve fast and dynamic switching between long TTIs and short TTIs) does not necessarily require the use of paired carriers. That is, since a thin control channel can be carried in the same direction, dynamic switching of TTIs can be quickly accomplished by a scheduling entity using a single TDD carrier to send downlink data at the same time as downlink data on the TDD carrier.

FDD-TDD carrier pairing

In some aspects of the present disclosure, a TDD carrier can be paired with a second carrier located in a frequency division duplex (FDD) band, where the FDD carrier can include paired uplink and downlink component carriers for providing full-duplex communication in the FDD band. As described in further detail below, this pairing enables dynamic uplink/downlink switching on a data channel on the TDD carrier with the help of a control channel on the FDD carrier.

FDD-TDD carrier pairing: multiplexing LoLat UL on conventional UL

Figure 5 shows an example of pairing a TDD carrier with an FDD carrier, which provides multiplexing of LoLat uplink transmissions on the TDD carrier with conventional uplink transmissions (i.e., transmissions from slave entities). In the example shown, the TDD carrier is shown in substantially the same manner as the TDD carrier in Figure 4, where the uplink resources allocated to different users are represented by larger blocks spanning long TTIs. Here, as described in further detail below, a slave entity (e.g., a UE) can request (and be granted) resources for LoLat transmissions, which can be multiplexed with "conventional" uplink transmissions from other users. At the top of the figure, resources on the FDD band (which include uplink component carriers and downlink component carriers) are allocated.

In the example shown, a control channel for controlling TDD uplink data is carried on an FDD component carrier. That is, the FDD band includes a thin feedback channel 506 in its uplink component carrier that can be used by a slave entity to send information such as a low-latency (LoLat) scheduling request 507. The FDD band also includes a thin control channel 508 in its downlink component carrier, which can carry uplink grant modification information 509 for modifying uplink resource grants corresponding to slave entity uplink transmissions on the TDD carrier. In addition, the FDD band also includes a LoLat grant channel 510 in its downlink component carrier, which can carry grant information 511 for a slave entity requesting LoLat scheduling for use in LoLat uplink transmissions on the TDD carrier.

In addition to the channels shown, time-frequency resources corresponding to a long TTI can be granted to one or more slave entities (e.g., users A-F) for uplink transmissions on the TDD carrier using any suitable downlink grant channel (not necessarily one of the channels shown). Since these uplink transmissions are ongoing, if a particular slave entity, designated as LoLat user 504, wishes to request resources for LoLat uplink transmissions, it can send a LoLat scheduling request 507 on a thin feedback channel 506 on an FDD uplink component carrier. Here, the LoLat scheduling request 507 can use a short TTI, but this is not always the case. In response, if the scheduling entity wishes to grant the requested LoLat resources, the scheduling entity 102 can send an uplink grant modification 509 on a thin control channel 508 and a LoLat grant 511 on a LoLat grant channel 511 on the FDD downlink component carrier. Here, the uplink grant modification 509 on the thin control channel 508 can be configured to inform all slave entities using existing uplink time-frequency resource grants that some or all of their granted resources are being modified to make way for LoLat transmissions. Furthermore, the LoLat grant 511 on the LoLat grant channel 510 can be configured to inform the slave entity sending the LoLat scheduling request (i.e., LoLat user 504) of its granted time-frequency resources. In this view, the LoLat grant 511 is shown as occupying a wider bandwidth than the UL grant modification 509. This indicates that while the UL grant modification 509 is merely a few bits indicating the frequency resources reallocated from the regular user 502 and a number of short TTIs, the LoLat grant 511 can include more precise information related to the LoLat resource assignment, such as user ID, assignment information, modulation and coding scheme, and so on. Thus, LoLat user 504 may send its LoLat uplink transmission on the TDD carrier, while other “regular” users 502 (e.g., users D, E, and F) may cease their uplink transmissions, resulting in an orthogonal multiple access scheme between conventional uplink transmissions and LoLat uplink transmissions on the TDD carrier.

In this example, a regular user 502 (e.g., a slave entity 104) whose uplink resources are punctured can benefit from having the ability to quickly decode the uplink grant modification 509. That is, the time from receiving the uplink grant modification 509 at the regular user 502 until the user stops its uplink transmission can be very short. To accommodate this fast reaction time, the slave entity 104 can be configured to quickly pause its uplink transmission, for example, by driving a zero input to the power amplifier within the transceiver 310, or in another example, quickly shutting down the power amplifier. In addition, the LoLat user 504 may also have only a brief time from receiving its LoLat uplink grant 511 and transmitting its LoLat uplink data. Therefore, fast processing of the LoLat grant 511 and transmission using the scheduled time-frequency resources would be beneficial and reduce latency.

FIG6 is a call flow diagram illustrating an exemplary resource assignment and reassignment process that may occur according to an example for multiplexing uplink data with different latency targets using a TDD data carrier paired with an FDD component carrier for control information. In this view, time moves forward in a downward direction, and the communication signals between the entities shown are marked with arrows between the lines below the corresponding entities. As shown, a scheduling entity 501 communicates with a plurality of subordinate entities 104 including a regular user 502 and a LoLat user 504. Each entity 501, 502, and 504 is configured to communicate on a TDD carrier and an FDD carrier. The corresponding TDD and FDD carriers are schematically illustrated using two vertical lines extending downward from each corresponding entity.

FIG6 is described below in conjunction with the flowchart shown in FIG7 . That is, FIG7 is a flowchart illustrating an exemplary process 700 for resource assignment and reassignment according to some aspects of the present disclosure. Process 700 is described from the perspective of scheduling entity 501 and, therefore, as described in conjunction with FIG6 , can be operated at the scheduling entity 102 described above in conjunction with FIG1 and/or FIG2 . In other examples falling within the scope of protection of the present disclosure, process 700 can be operated by a general-purpose processor, a processing system 214 as described above and shown in FIG2 , or any appropriate unit for performing the described functions. The particular order of steps or blocks shown in FIG7 is merely exemplary in nature, and in various aspects of the present disclosure, these steps or blocks can occur in any appropriate order, with some examples including two or more steps or blocks occurring simultaneously.

At block 702, the scheduling entity 501 may send a first assignment or grant 510 of time-frequency resources to at least one dependent entity on an FDD downlink component carrier. Any suitable control channel (e.g., a downlink assignment channel) on the FDD downlink component carrier may be used for the first resource assignment. Here, the first resource assignment 510 may be configured to indicate which time-frequency resource(s) are allocated to the corresponding dependent entity for regular transmission of uplink data, i.e., transmission using a long TTI. Based on the first resource assignment 510, at block 704, the scheduling entity 501 may receive regular uplink data 512 from at least one dependent entity (e.g., dependent entities 502 and 504) on the TDD uplink carrier using a long TTI. Here, with reference to FIG. 5 , the regular uplink data 512 may correspond to transmissions from a regular user 502. As shown in FIG6 with dashed arrows, regular uplink data may optionally be sent from the second slave entity 504 depending on the contents of the first resource assignment 510 and whether the second slave entity 504 is configured to send uplink data transmissions using a long TTI.

Blocks 702 and 704 may be repeated, or iterated multiple times in various examples, as regular uplink data 512 may continue to be sent from the slave entity. However, at any given time, it may occur that the slave entity 504 (i.e., the LoLat user 504) may wish to send LoLat data to the scheduling entity 501. Therefore, at block 706, the scheduling entity 501 may receive a LoLat scheduling request 507 from the LoLat user 504 (i.e., the second slave entity 504) on a thin feedback channel 506 on an FDD uplink component carrier. The LoLat scheduling request 507 may include information identifying the requesting slave entity 504 and any relevant information related to the LoLat data desired to be sent.

At block 708, the scheduling entity 501 may transmit an uplink scheduling grant modification 509 on a thin control channel 508 on an FDD downlink component carrier. Here, the uplink scheduling grant modification 509 may instruct regular users, such as the first slave entity 502, which have granted time-frequency resources for long TTI uplink transmissions, to puncture their uplink transmissions during at least one designated short TTI. Furthermore, at block 710, the scheduling entity 501 may transmit a second resource assignment or grant 511 of time-frequency resources to the requesting slave entity (i.e., the LoLat user 504) on a LoLat grant channel 510 on the FDD downlink component carrier. Here, the second resource assignment 511 may include information identifying the requesting slave entity 504 and information identifying the time-frequency resources granted for LoLat uplink transmissions on the TDD uplink carrier. In some examples, the transmission of the uplink scheduling grant modification 509 at block 708 and the transmission of the second resource assignment 511 at block 710 can occur simultaneously. That is, these transmissions can be multiplexed, for example, using different time-frequency resources. In other examples, these transmissions can be at different times, depending on the details of the specific implementation.

Block 712 represents operations at one or more slave entities (e.g., regular user 502 and LoLat user 504). That is, in response to the uplink grant modification 509, the regular user (i.e., the first slave entity 502) may puncture their previously scheduled uplink data transmissions using the long TTI. Furthermore, in response to the second resource assignment 511, the LoLat user (i.e., the second slave entity 504) may transmit LoLat uplink data 514 on the TDD carrier using the assigned time-frequency resources.

At block 714, the scheduling entity 501 may receive the LoLat uplink data 514 sent from the requesting slave entity 504 using a short TTI on the TDD carrier.

Block 716 represents operations at one or more slave entities (e.g., conventional user 502 and, in some examples, LoLat user 504). That is, when the transmission of LoLat uplink data has completed, the conventional slave entities may resume their conventional uplink data transmission on the TDD uplink carrier. Accordingly, at block 718, the scheduling entity 502 may resume receiving conventional uplink data from the one or more slave entities on the TDD uplink carrier using long TTIs.

By using the above scheme of pairing a TDD carrier for uplink data transmission with an FDD carrier for control channel transmission, the thin control channel 508 enables the scheduling entity to multiplex at least two different data types or categories with different TTIs for uplink transmission from a set of subordinate entities.

FDD-TDD carrier pairing: multiplexing LoLat DL on conventional UL

FIG8 shows another example of pairing a TDD carrier with an FDD carrier, which provides multiplexing of LoLat downlink transmissions (i.e., transmissions from a scheduling entity) and conventional uplink transmissions (i.e., transmissions from a slave entity) on a TDD carrier. In the example shown, the TDD carrier is shown in substantially the same manner as the TDD carrier in FIG4, where the uplink resources are shown as multiple users (slave entities) using long TTIs to send "conventional" uplink data. Here, as described in further detail below, the scheduling entity can modify the scheduling assignment or grant of time-frequency resources, which interrupts the ongoing uplink transmission on the TDD carrier using a downlink transmission on the TDD carrier.

In the example shown, a control channel for controlling user data carried on TDD is carried on the FDD downlink component carrier. That is, the FDD band includes a LoLat grant channel 808 in its downlink component carrier that a slave entity can use to receive information such as LoLat downlink grants 810.

In this example, since the FDD carrier is paired with the TDD carrier, the slave entity can always receive the control channel in the downlink direction on the FDD carrier, even when uplink transmission is in progress on the TDD carrier. In addition, in one aspect of the present disclosure, if a particular slave entity is not currently transmitting uplink data on the TDD carrier, then the particular user can always be configured to listen to downlink data on the TDD carrier.

In addition to the channels shown, time-frequency resources corresponding to a long TTI may be granted to one or more dependent entities (e.g., users A-F) for uplink transmission on the TDD carrier using any suitable downlink grant channel (not necessarily one of the channels shown).

At any given time, while regular user 802 is transmitting uplink data on a TDD carrier, the scheduling entity may determine to transmit LoLat downlink data on the TDD carrier. That is, at any given time, one or more dependent entities (e.g., LoLat users 804) communicating with the scheduling entity may begin to need to conduct LoLat communications with the network, where this situation requires more stringent latency requirements for communications than the relatively long latency incurred by regular users communicating using long TTIs. Therefore, in one aspect of the present disclosure, the availability of LoLat grant channels 808 on FDD downlink component carriers can enable dynamic multiplexing of traffic for one or more dependent entities (hereinafter referred to as LoLat users 804) that desire low-latency communications and use short TTIs for data traffic, and traffic for regular users 802 that use long TTIs for data traffic.

Thus, at any given time, the scheduling entity may broadcast a LoLat downlink grant 810 on the LoLat grant channel 808 on the FDD downlink component carrier. The LoLat downlink grant 810 may be structured in any suitable manner. For example, the LoLat downlink grant 810 may include information identifying one or more LoLat users to whom LoLat downlink data is being granted, information identifying the time-frequency resources being allocated to the users, and any other suitable information related to the reception and decoding of downlink data.

At the same time, on the TDD carrier, the scheduling entity may broadcast LoLat downlink data to the LoLat user 804 based on the LoLat downlink grant 810. That is, in some examples, the LoLat downlink grant 810 and the LoLat downlink data may be sent at the same time, i.e., during the same short TTI. However, this is not necessarily the case. In other examples, the LoLat downlink grant 810 and the LoLat downlink data may be sent during completely non-overlapping short TTIs, or as shown in FIG8 , a single short TTI may be used for the LoLat downlink grant 810, wherein the LoLat downlink grant 810 may overlap with any number of short TTIs (including zero) during which the LoLat downlink data is sent on the TDD carrier.

That is, the LoLat user 804 (i.e., the dependent entity indicated in the LoLat grant 810) can be configured to receive and buffer frames on the TDD carrier even if it is not actively receiving regular downlink data on the TDD carrier. When the LoLat downlink grant is processed (which may occur at the end of each long TTI), if the corresponding LoLat grant 810 is received on the LoLat grant channel 808, the LoLat user 804 can decode the LoLat downlink data sent on the TDD carrier accordingly.

At the scheduling entity, before the LoLat downlink data transmission on the TDD carrier, it is receiving a regular uplink transmission from a regular user 802. At the time of the LoLat transmission, in order to accommodate the downlink transmission of LoLat data on the TDD carrier, the scheduling entity may stop receiving any regular uplink data transmission on the TDD carrier and may start sending downlink LoLat data on the TDD carrier. Here, regular users 802 may continue to send their regular uplink data on the TDD carrier because they may not have received an advance warning or indication that the scheduling entity will not monitor their uplink transmission on the TDD carrier during the corresponding short TTI. After completing the LoLat downlink transmission on the TDD carrier, the scheduling entity may switch back and turn on its receiver to receive the ongoing additional regular uplink data transmission on the TDD carrier.

In some aspects of the present disclosure, regular users 802 that are interrupted by LoLat downlink transmissions may not have any indication that they are in fact interrupted and their uplink transmissions are temporarily ignored. In other words, the scheduling entity does not need to inform the regular users 802 that their uplink transmissions are interrupted/ignored to accommodate the LoLat downlink transmissions.

One potential impact of this approach could be some degree of inter-cell interference (e.g., when two high-power base stations are adjacent to each other) caused to other neighboring scheduling entities when the scheduling entity sends its LoLat downlink transmission on the TDD carrier. Furthermore, inter-user interference (IUI) could occur, where regular users 802, which may continue to send their uplink data on the TDD carrier, could impact the reception performance of LoLat users 804.

Thus, in another aspect of the present disclosure, regular users 802 may be able to monitor an FDD downlink carrier (including transmissions on the LoLat grant channel 808) while transmitting their regular uplink data on the TDD carrier. Here, in some examples, the FDD downlink carrier may include additional control information for regular users 802, which may indicate to those users that their uplink transmissions on the TDD carrier are being interrupted by the LoLat user. In this way, regular users 802 may be enabled to cease their uplink transmissions on the TDD carrier, which reduces or prevents potential interference with LoLat downlink data received by LoLat user 804 on the TDD carrier. In another aspect of the present disclosure, after the end of the LoLat downlink transmission, a guard time 806 may be used before regular users 802 resume transmission of their regular uplink data on the TDD carrier. In some examples, this guard time 806 may be eliminated.

FIG9 is a call flow diagram illustrating an exemplary resource assignment and reassignment process that may occur according to an example for multiplexing uplink data and downlink data with different latency targets using a TDD data carrier paired with an FDD component carrier for control information. In this view, time moves forward in a downward direction, and the communication signals between the entities shown are marked with arrows between the lines below the corresponding entities. As shown, a scheduling entity 801 communicates with a plurality of subordinate entities 104 including a regular user 802 and a LoLat user 804. Each entity 801, 802, and 804 is configured to communicate on a TDD carrier and an FDD carrier. The corresponding TDD and FDD carriers are schematically illustrated using two vertical lines extending downward from each corresponding entity.

FIG. 9 is described below in conjunction with the flowchart shown in FIG. 10 . That is, FIG. 10 is a flowchart illustrating an exemplary process 1000 for resource assignment and reassignment using a TDD data carrier paired with an FDD component carrier for control information, in accordance with aspects of the present disclosure. Process 1000 is described from the perspective of scheduling entity 801 and, as described in conjunction with FIG. 9 , may correspondingly operate at scheduling entity 102 as described above in conjunction with FIG. 1 and/or FIG. 2 . In other examples within the scope of the present disclosure, process 1000 may be operated by a general-purpose processor, the processing system 214 described above and shown in FIG. 2 , or any other suitable means for performing the described functionality. The particular order of steps or blocks shown in FIG. 10 is merely exemplary in nature, and in various aspects of the present disclosure, these steps or blocks may occur in any suitable order, with some examples including two or more steps or blocks occurring simultaneously.

At block 1002, the scheduling entity 801 may send a first assignment or grant 820 of time-frequency resources to at least one dependent entity on an FDD downlink component carrier. Any suitable control channel (e.g., a downlink assignment channel) on the FDD downlink component carrier may be used for the first resource assignment. Here, the first resource assignment 820 may be configured to indicate which time-frequency resource(s) are assigned to the respective dependent entity for regular transmission of uplink data, i.e., transmission using a long TTI. Based on the first resource assignment 820, at block 1004, the scheduling entity 801 may receive regular uplink data 822 from at least one dependent entity (e.g., dependent entities 802 and 804) on the TDD uplink carrier using a long TTI. Here, with reference to FIG. 8 , the regular uplink data 822 may correspond to a transmission from a regular user 802. As shown in FIG. 9 with dashed arrows, regular uplink data may optionally be sent from the second slave entity 804 depending on the contents of the first resource assignment 820 and whether the second slave entity 804 is configured to send uplink data transmissions using a long TTI.

Blocks 1002 and 1004 may be repeated, or iterated multiple times in various examples, as regular uplink data 822 may continue to be sent from the slave entity. However, at any given time, it may occur that the scheduling entity 801 may wish to send LoLat data to a specific slave entity (i.e., LoLat user 804). Therefore, at block 1006, the scheduling entity 801 may send an assignment or grant 820 of time-frequency resources to at least one slave entity (e.g., LoLat user 804) on a LotLat grant channel 808 on an FDD downlink component carrier. Here, the resource assignment 810 may instruct the LotLat user 804 to receive LotLat downlink data from the scheduling entity 801 using at least one short TTI. Specifically, the resource assignment 810 may include information identifying the specific slave entity 804 and information identifying the time-frequency resources granted on the TDD carrier for LoLat downlink transmission.

At block 1008, the scheduling entity 801 may optionally (as indicated by the dashed box 1008) send an uplink scheduling grant modification 809 on any appropriate channel on the FDD downlink component carrier. Here, the uplink scheduling grant modification 809 may instruct regular users such as the first slave entity 802 (which have granted time-frequency resources for long TTI uplink transmissions) to puncture their uplink transmissions during at least one designated short TTI (i.e., the short TTI corresponding to the LoLat grant 810).

Block 1010 represents operations at one or more slave entities (e.g., regular user 802 and LoLat user 804). That is, in response to uplink grant modification 809, regular users (i.e., first slave entity 802) may optionally puncture their previously scheduled uplink data transmissions using a long TTI. This puncturing operation is an optional step that may be performed at a slave entity configured to monitor a control channel on an FDD downlink component carrier while simultaneously transmitting uplink data on a TDD carrier.

At block 1012, the scheduling entity 801 may transmit LoLat downlink data 824 on the TDD carrier based on the resource assignment 810. In some examples, the transmission of the LoLat grant 810 and the LoLat downlink data may occur at the same time, i.e., during the same short TTI. However, this is not necessarily the case, and in other examples, the LoLat downlink grant 810 and the LoLat downlink data may be transmitted during completely non-overlapping short TTIs, or, as shown in FIG8 , a single short TTI may be used for the LoLat downlink grant 810, which may overlap with any number of short TTIs (including zero) during which the LoLat downlink data is transmitted on the TDD carrier.

Blocks 1014 and 1016 represent operations at one or more slave entities (e.g., regular user 802 and, in some examples, LoLat user 804). That is, at block 1014, after the scheduled LoLat downlink transmission 824 ends, the regular slave entity may optionally wait for an appropriate gap or guard time 806. For example, the guard time 806 may compensate for any propagation delay or other air interface delay, allowing the LoLat downlink transmission to all users in the service area to be fully completed before resuming any uplink transmission on the TDD carrier. At block 1016, when the transmission of the LoLat downlink data has completed (and optionally after the guard time 806), the regular slave entity (i.e., regular user 802) may resume its regular uplink data transmission on the TDD carrier. Accordingly, at block 1018, the scheduling entity 802 may resume receiving regular uplink data from the one or more slave entities on the TDD carrier using long TTIs.

By using the above scheme of pairing a TDD carrier for data transmission with an FDD carrier for control channel transmission, the thin LoLat grant channel 808 enables the scheduling entity to quickly and dynamically control the multiplexing of uplink data and downlink data of at least two different data types or categories from a set of dependent entities on the TDD carrier.

FDD-TDD carrier pairing: multiplexing LoLat UL on conventional DL

Figure 11 shows another example of pairing a TDD carrier with an FDD carrier, which provides for multiplexing LoLat uplink transmissions (i.e., transmissions from a slave entity) with conventional downlink transmissions (i.e., transmissions from a scheduling entity). In the example shown, the TDD carrier is shown in substantially the same manner as the TDD carrier in Figure 8, where the downlink resources are shown as the scheduling entity sending "conventional" downlink data to multiple users (slave entities) using a long TTI. Here, as described in further detail below, upon request by the slave entity, the scheduling entity can modify the scheduling assignment or grant of the time-frequency resources, which interrupts the ongoing downlink transmission on the TDD carrier to enable uplink transmission (e.g., LoLat data transmission) on the TDD carrier.

In the example shown, a control channel for controlling data carried on a TDD carrier is carried on an FDD downlink component carrier. That is, the FDD band includes a LoLat grant channel 1108 in its downlink component carrier that a slave entity can use to receive information such as a LoLat uplink grant 1110, wherein the LoLat uplink grant 1110 can carry grant information for a LoLat user 1104 that has requested LoLat scheduling for sending a LoLat uplink transmission. The FDD band also includes a thin control channel 1112 in its downlink component carrier that can carry a downlink grant modification 1114, wherein the downlink grant modification 1114 is used to modify the downlink time-frequency resource grant corresponding to downlink data reception by a regular user 1102 on the TDD carrier.

In this view, the LoLat grant 1110 is shown to occupy a wider bandwidth than the DL grant modification 1114. This means that while the DL grant modification 1114 is just a few bits indicating the frequency resources and a number of short TTIs that are reallocated away from the regular user 1102, the LoLat grant 1110 may include more precise information about the LoLat resource assignment, such as user ID, assignment information, modulation and coding scheme, etc.

In addition, a control channel is carried on the FDD uplink component carrier to enable the slave entity to quickly send information to the scheduling entity. That is, the FDD band includes a thin feedback channel 1116 in its uplink component carrier, where the scheduling entity can receive feedback information such as LoLat scheduling request 1118 from the slave entity.

In addition to the channels shown, time-frequency resources corresponding to a long TTI can be granted to one or more slave entities (e.g., users A-F) for downlink transmissions on the TDD carrier using any suitable downlink grant channel (not necessarily one of the channels shown). Since these downlink transmissions are ongoing, if a particular slave entity, designated as LoLat user 1104, wishes to request resources for LoLat uplink transmissions, it can send a LoLat scheduling request 1118 on a thin feedback channel 1116 on an FDD uplink component carrier. Here, the LoLat scheduling request 1118 can use a short TTI, but this is not always the case. In response, if the scheduling entity wishes to grant the requested LoLat resources, the scheduling entity 102 can send a LoLat grant 1110 on the FDD downlink component carrier, which informs the LoLat user 1104 that sent the LoLat user scheduling request 1118 of its granted resources. After an appropriate delay to allow the LoLat user to receive and process the LoLat grant 1110 and prepare its LoLat uplink transmission, the scheduling entity may also send a downlink grant modification on the thin control channel 1112, which informs the regular users 1102 receiving downlink data transmissions on the TDD carrier that some or all of their granted resources are being modified or removed to make way for the LoLat transmission.

Since the data carrier is a TDD carrier, downlink data transmission to the regular user 1102 using a long TTI is punctured, stopped, or paused during the time when the LoLat user 1104 is transmitting uplink data. During this time, the LoLat user 1104 can transmit its LoLat uplink transmission on the TDD carrier, which results in an orthogonal multiple access scheme between the regular downlink transmission and the LoLat uplink transmission on the TDD carrier.

In some examples, the scheduling entity may suspend its regular downlink data transmission on the TDD carrier just before the scheduled start of the LoLat uplink transmission. That is, when multiplexing LoLat uplink transmissions and regular downlink transmissions on the TDD carrier, a gap or guard time 1106 may optionally be used. Here, the guard time 1106 may, for example, compensate for any propagation delay or other air interface delay, allowing regular downlink transmissions to all users in the service area to be fully completed before the start of the LoLat uplink transmission on the TDD carrier.

In this view, the downlink grant modification is shown to occur at the same time as the downlink resources are modified.As described above, the need to advance the timing of the grant modification can be avoided because the receiving conventional UE can buffer and post-process the downlink grant modification and downlink data.

Figure 12 is a call flow diagram illustrating an exemplary resource assignment and reassignment process that may occur according to an example for multiplexing uplink data and downlink with different latency targets using a TDD data carrier paired with an FDD component carrier for control information. In this view, time moves forward in a downward direction, and the communication signals between the entities shown are marked with arrows between the lines below the corresponding entities. As shown, a scheduling entity 1101 communicates with a plurality of subordinate entities 104 including a regular user 1102 and a LoLat user 1104. Each entity 1101, 1102, and 1104 is configured to communicate on a TDD carrier and an FDD carrier. The corresponding TDD and FDD carriers are schematically illustrated using two vertical lines extending downward from each corresponding entity.

FIG. 12 is described below in conjunction with the flowchart shown in FIG. 13 . That is, FIG. 13 is a flowchart illustrating an exemplary process 1300 for resource assignment and reassignment using a TDD data carrier paired with an FDD component carrier for control information, in accordance with aspects of the present disclosure. Process 1300 is described from the perspective of scheduling entity 1101 and, as described in conjunction with FIG. 12 , may correspondingly operate at scheduling entity 102 as described above in conjunction with FIG. 1 and/or FIG. 2 . In other examples within the scope of the present disclosure, process 1300 may be operated by a general-purpose processor, the processing system 214 described above and shown in FIG. 2 , or any suitable means for performing the described functionality. The particular order of steps or blocks shown in FIG. 13 is merely exemplary in nature, and in various aspects of the present disclosure, these steps or blocks may occur in any suitable order, with some examples including two or more steps or blocks occurring simultaneously.

At block 1302, the scheduling entity 1101 may send a first assignment or grant 1120 of time-frequency resources to at least one dependent entity on an FDD downlink component carrier. Any suitable control channel (e.g., a downlink assignment channel) on the FDD downlink component carrier may be used for the first resource assignment. Here, the first resource assignment 1120 may be configured to indicate which time-frequency resource(s) are assigned to the respective dependent entity for receiving a regular transmission of downlink data, i.e., a transmission using a long time-to-transmit (TTI). Based on the first resource assignment 1120, at block 1304, the scheduling entity 1101 may send regular downlink data 1122 to at least one dependent entity (e.g., dependent entities 1102 and 1104) on the TDD downlink carrier using a long time-to-transmit (TTI). Here, with reference to FIG. 11 , the regular downlink data 1122 may correspond to a downlink transmission to a regular user 1102. As shown in FIG12 with dashed arrows, regular downlink data may optionally be sent to the second slave entity 1104 depending on the contents of the first resource assignment 1120 and whether the second slave entity 1104 is configured to receive downlink data transmissions using long TTIs.

Blocks 1302 and 1304 may be repeated, or iterated multiple times in various examples, as regular downlink data 1122 may continue to be sent to the slave entity. However, at any given time, it may occur that the slave entity 1104 (i.e., LotLat user 1104) may wish to send LoLat uplink data to the scheduling entity 1101. Therefore, at block 1306, the scheduling entity 1101 may receive a LoLat scheduling request 1118 from the LoLat user 1104 (i.e., the second slave entity 1104) on a thin feedback channel 1116 on an FDD uplink component carrier. The LoLat scheduling request 1118 may include information identifying the requesting slave entity 1104 and any relevant information regarding the LoLat data desired to be sent.

At block 1308, the scheduling entity 1101 may send a second assignment or grant 1110 of time-frequency resources to the requesting slave entity 1104 on a LoLat grant channel 1108 on the FDD downlink component carrier. Here, the second resource assignment 1110 may include information identifying the requesting slave entity 1104 and information identifying the time-frequency resources granted on the TDD uplink carrier for LoLat uplink transmission.

At optional block 1310, just before the scheduled LoLat uplink transmission begins, the scheduling entity 1101 may suspend its regular downlink data transmission on the TDD carrier. That is, when multiplexing LoLat uplink transmissions 1124 and regular downlink transmissions 1122 on the TDD carrier, a gap or guard time 1106 may optionally be used.

At block 1312, the scheduling entity 1101 may send a downlink scheduling grant modification 1114 on a thin control channel 1112 on an FDD downlink component carrier. Here, the downlink scheduling grant modification 1114 may instruct a regular user, such as the first slave entity 1102, which has granted time-frequency resources for long TTI downlink transmission, to ignore any uplink transmissions during at least one designated short TTI. In other words, since the transmission during the TTI is a LoLat uplink transmission from the LoLat user 1104 and not for the regular user 1102, the data may not be decoded by the regular user 1102 and may be ignored by the regular user 1102 during post-processing of the corresponding long TTI.

Block 1314 represents operations at one or more slave entities (e.g., LoLat user 1104). That is, in response to the second resource assignment 1110, the LoLat user (i.e., the second slave entity 1104) may transmit LoLat uplink data 1124 using the assigned time-frequency resources on the TDD carrier.

In some examples, the transmission of the downlink scheduling grant modification 1114 at block 1312 and the transmission of the LoLat uplink data 1124 on the TDD carrier at block 1314 (and the corresponding pause in downlink data on the TDD carrier, excluding any guard time that may be added) can occur simultaneously. That is, for example, these transmissions can be multiplexed using different time-frequency resources. In other examples, depending on the details of the specific implementation, these transmissions can be at different times. That is, the regular user 1102 can be configured to buffer or cache the contents of the thin control channel 1112 and the TDD carrier so that the regular user 1102 can perform a data ignore operation during a specified short TTI during post-processing.

At block 1316, the scheduling entity 1101 may receive LoLat uplink data 1124 sent from the requesting slave entity 1104 using short TTIs on the TDD carrier. At block 1318, the scheduling entity 1101 may resume using long TTIs to send regular downlink data 1122 to one or more slave entities (e.g., regular users 1102) on the TDD uplink carrier.

By using the above scheme of pairing a TDD carrier for uplink data transmission with an FDD carrier for control channel transmission, the thin control channel 1112 enables the scheduling entity to multiplex uplink data and downlink data for a set of subordinate entities having at least two different data types or categories.

TDD-TDD carrier pairing

In another aspect of the present disclosure, instead of pairing an FDD carrier with a TDD carrier, two TDD carriers are paired with each other in a manner that enables full-duplex communication. Figure 14 shows an example of pairing two TDD component carriers (CCs). In this view, a first CC (component carrier 1 or CC1) is paired with a second CC (component carrier 2 or CC2). The horizontal axis represents time and the vertical axis represents frequency (not depicted to scale). Both CC1 and CC2 are TDD carriers, where, on each respective carrier, the uplink time slot indicated by U is time multiplexed with the downlink time slot indicated by D. In addition, some time slots are identified as special time slots and indicated by S, which are further described below. Here, a time slot can correspond to any appropriate duration and can correspond to other terms such as transmission time interval (TTI), subframe, frame, symbol duration, etc.

If the communication device can only use CC1, it can be observed that at any single time, there are only downlink time slots, uplink time slots, or special time slots. This view shows two different types of frames, which are identified as configuration A and configuration B. In the first frame identified as configuration A, there are the same number of uplink time slots U and downlink time slots D, two of which are identified as special time slots S. In the second frame identified as configuration B, most of the time slots are downlink time slots D, with one uplink time slot U and one special time slot S. The third frame is shown as another configuration A frame. These configurations are just examples, which correspond to some existing configurations specified in the TD-LTE standard.

For example, at any time during the second frame identified as Configuration B, if a communications device needs to send feedback on the uplink, it may not be presented with such an opportunity due to the long period of downlink-only time slots it faces. Here, there is no need to buffer the feedback, at least until the next opportunity is presented in the third time slot of the third frame.

Thus, in one aspect of the present disclosure, a first TDD component carrier CC1 may be paired with a second TDD component carrier CC2. Here, CC2 may implement an inverse, conjugate, or complementary transmit/receive organization relative to CC1. In the present disclosure, the terms inverse, complementary, and conjugate are used interchangeably and generally refer to a configuration in which at least some downlink time slots D in CC1 are paired with uplink time slots U in CC2, and at least some uplink time slots U in CC1 are paired with downlink time slots D in CC2. The configurations shown are exemplary in nature, and other configurations may be used within the scope of the present disclosure, some of which may pair all time slots across both component carriers, while other configurations may include some unpaired uplink/downlink time slots.

As shown, a configuration A frame is paired with a configuration-A frame, where configuration-A represents the inverse (or conjugate) of configuration A. Similarly, a configuration B frame is paired with a configuration-B frame.

In the example shown, a special time slot, indicated by S, may be used for downlink-to-uplink switching. That is, with reference to communications conducted by slave entity 104, when using a TDD carrier, a certain time gap may be required when switching from downlink time slot D to uplink time slot U, with scheduling entity 102 driving the timing for both uplink and downlink transmissions. This means that there is a certain propagation delay between transmissions in downlink time slot D from scheduling entity 102 to slave entity 104, and between transmissions in uplink time slot U from slave entity 104 to scheduling entity 102. To account for these propagation delays, special time slot S inserts a gap between the end of downlink time slot D and the beginning of uplink time slot U, allowing scheduling entity 102 and slave entity 104 to maintain synchronization. This gap may correspond to times when neither uplink nor downlink communication is occurring. The length of the gap in special time slot S may be configured based on the size of the cell.

In various aspects of the present disclosure, a special time slot S in a component carrier can be paired with any appropriate time slot (including a downlink time slot D, an uplink time slot U, or another special time slot S) on its paired component carrier. In some examples, such as the example shown in FIG14 , each special time slot S in a component carrier (CC1) can be mapped (e.g., time-aligned) to a corresponding downlink time slot in its paired component carrier (CC2). However, this is merely an example and is not limiting in nature.

In another example, a special time slot S may be inserted between the transitions from the downlink time slot to the uplink time slot in the inverse or paired component carrier CC2 as needed.

In some examples, the paired component carriers may be inter-band carriers. That is, each of component carriers CC1 and CC2 may be located in a frequency band different from the frequency band in which its paired component carrier is located. By placing these component carriers in different frequency bands, RF functionality at devices such as scheduling entity 102 and slave entity 104 may be improved, which reduces interference and de-sense between the respective carriers. However, this is not a requirement, and it is within the scope of the present disclosure that intra-band component carriers may be used; however, in such cases, it is beneficial to select component carriers that are as far apart in frequency as practicable.

As an example, the view in Figure 14 shows two paired TDD component carriers with substantially the same bandwidth. That is, each component carrier has the same width in the vertical frequency dimension. Here, if two TDD component carriers of the same bandwidth are paired with each other, one of the benefits of traditional TDD carriers may be lost. That is, traditional TDD has the following advantages: depending on the characteristics of the service, it can be determined how many time slots can be used for downlink services and how many time slots can be used for uplink services, enabling dynamic assignment and providing the most efficient use of available resources. If the paired component carriers have the same bandwidth, this flexibility will be lost if all time slots in one direction in one component carrier are paired with time slots in the other direction in its paired component carrier. That is, with this configuration, the sum of the downlink time slots on the two component carriers will be equal to the sum of the uplink time slots on the two component carriers.

15 illustrates conjugate pairings of component carriers configured to provide a degree of flexibility in allocating uplink and downlink time slots according to further aspects of the present disclosure.

The reason for desiring full duplex is not necessarily for the benefit of the traffic channel. Rather, as described above, full duplex communication may be desirable because it can provide additional control, for example, by enabling thin feedback and thin grants to enable dynamic modification of communications.

Thus, as shown in Figure 14, a first TDD component carrier CC1 having a wider bandwidth (e.g., 100 MHz) can be paired with a second TDD component carrier CC2 having a narrower bandwidth (e.g., 10 MHz). The ratio between the bandwidths of the two component carriers does not need to be the 10:1 ratio given here, and any suitable ratio may be used within the scope of the present disclosure. The selection of the ratio may be based on the characteristics of the traffic carried on the uplink and downlink, for example, the degree of asymmetry between uplink and downlink traffic. For example, significantly heavier traffic on the downlink may be accommodated by deploying a larger number of downlink timeslots on the wider bandwidth component carrier.

In some examples, the bandwidth of one or both of the TDD component carriers may be selected based on a desired or required bandwidth; and in some examples, the bandwidth of one or both of the TDD component carriers may be configured by a scheduling entity or a subordinate entity.

TDD-TDD carrier pairing: multiplexing LoLat UL on conventional UL

Figure 16 shows an example of pairing a first TDD carrier with a second TDD carrier, which provides multiplexing of LoLat uplink transmissions on the primary TDD component carrier with conventional uplink transmissions (i.e., transmissions from slave entities). In the example shown, the primary TDD component carrier is shown in substantially the same manner as the TDD carrier in Figure 5, where the uplink resources allocated to different users are represented by larger blocks spanning long TTIs. Here, as described in further detail below, a slave entity (e.g., UE) can request and be granted resources for LoLat transmissions, which can be multiplexed with conventional uplink transmissions from other users. At the bottom of the figure, resources on the second TDD component carrier are allocated for use.

In the example shown, a control channel for controlling uplink data transmission on the primary TDD component carrier is carried on the secondary TDD component carrier. That is, the secondary TDD component carrier includes a thin control channel 1606 that can carry uplink grant modification information 1608, where the uplink grant modification information 1608 modifies the uplink resource grant corresponding to the uplink transmission of the slave entity (i.e., regular user 1602) on the primary TDD component carrier. In addition, the secondary TDD component carrier includes a LoLat grant channel 1610, which can carry grant information 1612 for the slave entity, where the slave entity requests LoLat scheduling (i.e., LoLat user 1604) for use in LoLat uplink transmission on the primary TDD component carrier.

Furthermore, in addition to the data carrier, the primary TDD component carrier includes a thin feedback channel 1614 that the slave entity (ie, LoLat user 1604 ) can use to send information such as a LoLat scheduling request 1616 .

In addition to the channels shown, time-frequency resources corresponding to a long TTI can be granted to one or more slave entities (e.g., users A-F) for uplink transmissions on the primary TDD component carrier using any suitable downlink grant channel (not necessarily one of the channels shown). Since these uplink transmissions are ongoing, if a particular slave entity, labeled as LoLat user 1604, wishes to request resources for LoLat uplink transmissions, it can send a LoLat scheduling request 1616 on a thin feedback channel 1614 on the primary TDD component carrier. Here, the LoLat scheduling request 1616 can use a short TTI, but this is not always the case. In response, if the scheduling entity wishes to grant the requested LoLat resources, the scheduling entity 102 can send an uplink grant modification 1608 on a thin control channel 1606 and a LoLat grant 1612 on a LoLat grant channel 1610 on the secondary TDD component carrier. Here, the uplink grant modification 1608 on the thin control channel 1606 can be configured to inform all slave entities using the granted uplink time-frequency resources on the primary TDD component carrier that some or all of their granted resources are being modified or removed to make way for LoLat transmissions. Furthermore, the LoLat grant 1612 on the LoLat grant channel 1610 can be configured to inform the slave entity that sent the LoLat scheduling request (i.e., LoLat user 1604) of its granted time-frequency resources. In this view, the LoLat grant 1612 is shown as occupying a wider bandwidth than the UL grant modification 1608. This indicates that while the UL grant modification 1608 may be just a few bits indicating the frequency resources reallocated from the regular user 1602 and a number of short TTIs, the LoLat grant 1612 can include more precise information related to the LoLat resource assignment, such as user ID, assignment information, modulation and coding scheme, and so on. Thus, LoLat user 1604 may send its LoLat uplink transmission on the primary TDD component carrier, while other regular users 1602 (e.g., users D, E, and F) may cease their uplink transmissions, resulting in an orthogonal multiple access scheme between regular uplink transmissions and LoLat uplink transmissions on the TDD carrier.

In this example, a regular user 1602 (e.g., a slave entity 104) whose uplink resources are punctured can benefit from having the ability to quickly decode uplink grant modifications 1608. That is, the time from receiving uplink grant modifications 1608 at regular user 1602 until the user stops its uplink transmission can be very short. To accommodate this fast reaction time, slave entity 104 can be configured to quickly pause its uplink transmission, for example, by driving a zero input to the power amplifier within transceiver 310, or in another example, by quickly shutting down the power amplifier. Furthermore, LoLat user 1604 may also have only a brief time between receiving its LoLat uplink grant 1612 and transmitting its LoLat uplink data. Therefore, fast processing of LoLat grants 1612 and transmission using scheduled time-frequency resources can be beneficial and reduce latency.

Figure 17 is a call flow diagram illustrating an exemplary resource assignment and reassignment process that may occur according to an example for multiplexing uplink data with different delay targets using a primary TDD component carrier paired with a secondary TDD component carrier. In this view, time moves forward in a downward direction, and the communication signals between the entities shown are marked with arrows between the lines below the corresponding entities. As shown, the scheduling entity 1601 communicates with a plurality of subordinate entities 104 including regular users 1602 and LoLat users 1604. Each entity 1601, 1602 and 1604 is configured to communicate on a primary TDD component carrier and a secondary TDD component carrier. The corresponding primary TDD component carrier and the secondary TDD component carrier are schematically illustrated using two vertical lines extending downward from each corresponding entity.

Figure 17 is described below in conjunction with the flowchart shown in Figure 18. That is, Figure 18 is a flowchart illustrating an exemplary process 1800 for resource assignment and reassignment according to some aspects of the present disclosure. Process 1800 is described from the perspective of scheduling entity 1601, and therefore, as described in conjunction with Figure 17, it can be operated at the scheduling entity 102 described above in conjunction with Figures 1 and/or 2. In other examples falling within the scope of protection of the present disclosure, process 1800 can be operated by a general-purpose processor, a processing system 214 as described above and shown in Figure 2, or any appropriate unit for performing the described functions. The particular order of steps or blocks shown in Figure 18 is merely exemplary in nature, and in various aspects of the present disclosure, these steps or blocks can occur in any appropriate order, with some examples including two or more steps or blocks occurring simultaneously.

At block 1802, the scheduling entity 1601 may send a first assignment or grant 1620 of time-frequency resources to at least one slave entity on a secondary TDD component carrier. Any suitable control channel (e.g., a downlink assignment channel) may be used for the first resource assignment. Here, the first resource assignment 1620 may be configured to indicate which time-frequency resource(s) are allocated to the respective slave entities for regular transmission of uplink data, i.e., transmission using a long TTI. Based on the first resource assignment 1620, at block 1804, the scheduling entity 1601 may receive regular uplink data 1622 from at least one slave entity (e.g., slave entities 1602 and 1604) on the primary TDD component carrier using a long TTI. Here, with reference to FIG. 16 , the regular uplink data 1622 may correspond to transmissions from a regular user 1602. As shown in FIG17 with dashed arrows, regular uplink data may optionally be sent from the second slave entity 1604 depending on the contents of the first resource assignment 1620 and whether the second slave entity 1604 is configured to send uplink data transmissions using a long TTI.

Blocks 1802 and 1804 may be repeated, or iterated multiple times in various examples, as regular uplink data 1622 may continue to be sent from the slave entity. However, at any given time, it may occur that the slave entity 1604 (i.e., LoLat user 1604) may wish to send LoLat data to the scheduling entity 1601. Therefore, at block 1806, the scheduling entity 1601 may receive a LoLat scheduling request 1616 from the LoLat user 1604 (i.e., the second slave entity 1604) on a thin feedback channel 1614 on the primary TDD component carrier. The LoLat scheduling request 1616 may include information identifying the requesting slave entity 1604 and any relevant information related to the LoLat data desired to be sent.

At block 1808, the scheduling entity 1601 may transmit an uplink scheduling grant modification 1608 on a thin control channel 1606 on the secondary TDD component carrier. Here, the uplink scheduling grant modification 1608 may instruct regular users, such as the first slave entity 1602, which have granted time-frequency resources for long TTI uplink transmissions, to puncture their uplink transmissions during at least one designated short TTI. Furthermore, at block 1810, the scheduling entity 1601 may transmit a second resource assignment or grant 1612 of time-frequency resources to the requesting slave entity (i.e., LoLat user 1604) on a LoLat grant channel 1610 on the secondary TDD component carrier. Here, the second resource assignment 1612 may include information identifying the requesting slave entity 1604 and information identifying the time-frequency resources granted on the primary TDD component carrier for LoLat uplink transmissions. In some examples, the transmission of the uplink scheduling grant modification 1608 at block 1808 and the transmission of the second resource assignment 1612 at block 1810 can occur simultaneously. That is, these transmissions can be multiplexed, for example, using different time-frequency resources. In other examples, these transmissions can be at different times, depending on the details of the specific implementation.

Block 1812 represents operations at one or more slave entities (e.g., regular user 1602 and LoLat user 1604). That is, in response to uplink grant modification 1608, regular users (i.e., first slave entity 1602) may puncture their previously scheduled uplink data transmissions using a long TTI. Furthermore, in response to second resource assignment 1612, LoLat users (i.e., second slave entity 1604) may transmit LoLat uplink data 1624 using the assigned time-frequency resources on the primary TDD component carrier.

At block 1814 , the scheduling entity 1601 may receive LoLat uplink data 1624 sent from the requesting slave entity 1604 using a short TTI on the primary TDD component carrier.

Block 1816 represents operations at one or more slave entities (e.g., regular user 1602 and, in some examples, LoLat user 1604). That is, when the transmission of LoLat uplink data 1624 has been completed, the regular slave entities may resume their regular uplink data transmission on the primary TDD component carrier. Accordingly, at block 1818, the scheduling entity 1602 may resume receiving regular uplink data 1622 from the one or more slave entities on the primary TDD component carrier using long TTIs.

By using the above scheme of pairing a primary TDD carrier for uplink data transmission and uplink feedback transmission with a secondary TDD component carrier for control channel transmission, the thin control channel 1606 enables the scheduling entity to multiplex at least two different data types or categories with different TTIs for uplink transmission from a set of subordinate entities.

TDD-TDD carrier pairing: multiplexing LoLat DL on conventional UL

Figure 19 shows another example of TDD-TDD component carrier pairing, which provides multiplexing of LoLat downlink transmissions (i.e., transmissions from the scheduling entity) and regular uplink transmissions (i.e., transmissions from the slave entity) on the primary TDD component carrier. In the example shown, the primary TDD component carrier is shown in a manner substantially the same as the TDD carrier in Figure 4, where the uplink resources are shown as multiple users (slave entities) using long TTIs to send "regular" uplink data. Here, as described in further detail below, the scheduling entity can modify the scheduling assignment or grant of time-frequency resources, which interrupts the ongoing uplink transmission on the primary TDD component carrier using a downlink transmission on the primary TDD component carrier.

In the example shown, a control channel for controlling user data carried on the primary TDD component carrier is carried on the secondary TDD component carrier. That is, the secondary TDD component carrier includes a LoLat grant channel 1910 that the slave entity can use to receive information such as LoLat downlink grants 1912.

In this example, because the secondary TDD component carrier is paired with the primary TDD component carrier (e.g., using the conjugate pairing described above), the slave entity can always receive the control channel in the downlink direction on the secondary TDD component carrier, even if uplink transmissions are occurring on the primary TDD component carrier. Furthermore, in one aspect of the present disclosure, if a particular slave entity is not currently transmitting uplink data on the primary TDD component carrier, the particular user can always be configured to listen to downlink data on the primary TDD component carrier.

In addition to the channels shown, time-frequency resources corresponding to the long TTI may be granted to one or more slave entities (e.g., users A-F) for uplink transmission on the primary TDD component carrier using any suitable downlink grant channel (not necessarily one of the channels shown).

At any given time, while regular user 1902 is transmitting uplink data on the primary TDD component carrier, the scheduling entity may determine to transmit LoLat downlink data on the primary TDD component carrier. That is, at any given time, one or more slave entities (e.g., LoLat user 1904) communicating with the scheduling entity may begin to need to conduct LoLat communications with the network, where such communications require more stringent latency requirements than the relatively long latency incurred by regular user communications using long TTIs. Therefore, in one aspect of the present disclosure, the availability of LoLat grant channels 1910 on the secondary TDD component carrier can enable dynamic multiplexing of traffic for one or more slave entities (hereinafter referred to as LoLat users 1904) that desire low-latency communications and use short TTIs for data traffic, and traffic for regular users 1902 that use long TTIs for data traffic.

Thus, at any given time, the scheduling entity may broadcast a LoLat downlink grant 1912 on the LoLat grant channel 1910 on the secondary TDD component carrier. The LoLat downlink grant 1912 may be structured in any suitable manner. For example, the LoLat downlink grant 1912 may include information identifying one or more LoLat users to whom LoLat downlink data is being granted, information identifying the time-frequency resources being allocated to the users, and any other suitable information related to the reception and decoding of downlink data.

At the same time, on the primary TDD component carrier, the scheduling entity may broadcast LoLat downlink data to the LoLat user 1904 based on the LoLat downlink grant 1912. That is, in some examples, the LoLat downlink grant 1912 and the LoLat downlink data may be sent at the same time (i.e., during the same short TTI). However, this is not necessarily the case, and in other examples, the LoLat downlink grant 1912 and the LoLat downlink data may be sent during completely non-overlapping short TTIs, or, as shown in FIG. 19 , a single short TTI may be used for the LoLat downlink grant 1912, which may overlap with any number (including zero) of short TTIs during which the LoLat downlink data is sent on the primary TDD component carrier.

That is, the LoLat user 1904 (i.e., the slave entity indicated in the LoLat grant 1912) can be configured to receive and buffer frames on the primary TDD component carrier even if it is not actively receiving regular downlink data on the primary TDD component carrier. When the LoLat downlink grant is processed (which may occur at the end of each long TTI), if the corresponding LoLat grant 1912 is received on the LoLat grant channel 1910, the LoLat user 1904 can decode the LoLat downlink data sent on the primary TDD component carrier accordingly.

At the scheduling entity, prior to the LoLat downlink data transmission on the primary TDD component carrier, it is receiving a regular uplink transmission from a regular user 1902. At the time of the LoLat transmission, to accommodate the downlink transmission of LoLat data on the primary TDD component carrier, the scheduling entity may stop receiving any regular uplink data transmission on the primary TDD component carrier and may begin sending downlink LoLat data on the primary TDD component carrier. Here, regular users 1902 may continue to send their regular uplink data on the primary TDD component carrier because they may not have received any advance warning or indication that the scheduling entity will not monitor their uplink transmission on the primary TDD component carrier during the corresponding short TTI. After the LoLat downlink transmission on the primary TDD component carrier is completed, the scheduling entity may switch back and turn on its receiver to receive the ongoing additional regular uplink data transmission on the primary TDD component carrier.

In some aspects of the present disclosure, regular users 1902 that are interrupted by LoLat downlink transmissions may not have any indication that they are in fact interrupted and their uplink transmissions are temporarily ignored. In other words, the scheduling entity does not need to inform regular users 1902 that their uplink transmissions are interrupted/ignored to accommodate LoLat downlink transmissions.

One potential impact of this approach may be some degree of inter-cell interference (e.g., when two high-power base stations are adjacent to each other) caused to other neighboring scheduling entities when the scheduling entity sends its LoLat downlink transmission on the primary TDD component carrier. In addition, inter-user interference may occur, where regular users 1902, which may continue to send their uplink data on the primary TDD component carrier, may affect the reception performance of LoLat users 1904.

Thus, in another aspect of the present disclosure, regular users 1902 may be able to monitor a secondary TDD component carrier (including transmissions on the LoLat grant channel 1910) while transmitting their regular uplink data on the primary TDD component carrier. Here, in some examples, the secondary TDD component carrier may include additional control information for regular users 1902, which may indicate to those users that their uplink transmissions on the primary TDD component carrier are being interrupted by the LoLat user. In this way, regular users 1902 may be caused to cease their uplink transmissions on the primary TDD component carrier, which reduces or prevents potential interference with LoLat downlink data received by LoLat users 1904 on the primary TDD component carrier. In another aspect of the present disclosure, after the end of the LoLat downlink transmission, a guard time 1906 may be used before regular users 1902 resume transmission of their regular uplink data on the primary TDD component carrier. In some examples, this guard time 1906 may be eliminated.

Figure 20 is a call flow diagram illustrating an exemplary resource assignment and reassignment process that may occur according to an example for multiplexing uplink data and downlink data with different delay targets using a set of paired primary component carriers and secondary TDD component carriers. In this view, time moves forward in a downward direction, and the communication signals between the entities shown are marked with arrows between the lines below the corresponding entities. As shown, the scheduling entity 1901 communicates with a plurality of subordinate entities 104 including regular users 1902 and LoLat users 1904. Each entity 1901, 1902 and 1904 is configured to communicate on a primary TDD component carrier and a secondary TDD component carrier. The corresponding primary TDD component carrier and the secondary TDD component carrier are schematically illustrated using two vertical lines extending downward from each corresponding entity.

FIG20 is described below in conjunction with the flowchart shown in FIG21. That is, FIG21 is a flowchart illustrating an exemplary process 2100 for resource assignment and reassignment using a set of paired primary TDD component carriers and secondary TDD carriers according to some aspects of the present disclosure. Process 2100 is described from the perspective of scheduling entity 1901, and thus, as described in conjunction with FIG20, it can be operated at the scheduling entity 102 described above in conjunction with FIG1 and/or FIG2, respectively. In other examples falling within the scope of the present disclosure, process 2100 can be operated by a general-purpose processor, the processing system 214 described above and shown in FIG2, or any suitable unit for performing the described functions. The specific order of steps or blocks shown in FIG21 is merely exemplary in nature, and in various aspects of the present disclosure, these steps or blocks can occur in any suitable order, with some examples including two or more steps or blocks occurring simultaneously.

At block 2102, the scheduling entity 1901 may send a first assignment or grant 1920 of time-frequency resources to at least one slave entity on a secondary TDD component carrier. Any suitable control channel (e.g., a downlink assignment channel) on the secondary TDD component carrier may be used for the first resource assignment 1920. Here, the first resource assignment 1920 may be configured to indicate which time-frequency resource(s) are assigned to the respective slave entities for regular transmission of uplink data, i.e., transmission using a long time-interval (TTI). Based on the first resource assignment 1920, at block 2104, the scheduling entity 1901 may receive regular uplink data 1922 from at least one slave entity (e.g., slave entities 1902 and 1904) on the primary TDD component carrier using a long time-interval (TTI). Here, with reference to FIG. 19 , the regular uplink data 1922 may correspond to transmissions from a regular user 1902. As shown in FIG. 20 with dashed arrows, regular uplink data 1922 may optionally be sent from the second slave entity 1904 depending on the contents of the first resource assignment 1920 and whether the second slave entity 1904 is configured to send uplink data transmissions using a long TTI.

Blocks 2102 and 2104 may be repeated, or iterated multiple times in various examples, as regular uplink data 1922 may continue to be sent from the slave entity. However, at any given time, it may occur that the scheduling entity 1901 may wish to send LotLat data to a particular slave entity (i.e., LotLat user 1904). Therefore, at block 2106, the scheduling entity 1901 may send an assignment or grant 1912 of time-frequency resources to at least one slave entity (e.g., LotLat user 1904) on a LotLat grant channel 1910 on a secondary TDD component carrier. Here, the resource assignment 1912 may instruct the LotLat user 1904 to receive LotLat downlink data from the scheduling entity 1901 using at least one short TTI. Specifically, the resource assignment 1912 may include information identifying the specific slave entity 1904 and information identifying the time-frequency resources granted for LoLat downlink transmission on the primary TDD component carrier.

At block 2108, the scheduling entity 1901 may optionally (as indicated by the dashed box 2108) send an uplink scheduling grant modification 1924 on any suitable channel, for example, on the secondary TDD component carrier. Here, the uplink scheduling grant modification 1924 may instruct regular users such as the first slave entity 1902 (which have granted time-frequency resources for long TTI uplink transmissions) to puncture their uplink transmissions during at least one designated short TTI (i.e., the short TTI corresponding to the LoLat grant 1912).

Block 2110 represents operations at one or more slave entities (e.g., regular user 1902 and LoLat user 1904). That is, in response to uplink grant modification 1924, the regular user (i.e., first slave entity 1902) may puncture their previously scheduled uplink data transmissions using a long TTI. This puncturing operation is an optional step that may be performed on a slave entity configured to monitor a control channel on a secondary TDD component carrier while transmitting uplink data on a primary TDD component carrier.

At block 2112, the scheduling entity 1901 may transmit LoLat downlink data 1926 on the primary TDD component carrier based on the resource assignment 1912. In some examples, the transmission of the LoLat grant 1912 and the LoLat downlink data 1926 may occur at the same time, i.e., during the same short TTI. However, this is not necessarily the case, and in other examples, the LoLat downlink grant 1912 and the LoLat downlink data may be transmitted during completely non-overlapping short TTIs, or, as shown in FIG. 19 , a single short TTI may be used for the LoLat downlink grant 1912, which may overlap with any number of short TTIs (including zero) during which the LoLat downlink data is transmitted on the primary TDD component carrier.

Blocks 2114 and 2116 represent operations at one or more slave entities (e.g., regular user 1902, and in some examples, LoLat user 1904). That is, at block 2114, after the scheduled LoLat downlink transmission 1926 ends, the regular slave entity may optionally wait for an appropriate gap or guard time 1906. For example, the guard time 1906 may compensate for any propagation delay or other air interface delay, which allows the LoLat downlink transmission to all users in the service area to be fully completed before resuming any uplink transmission on the primary TDD component carrier. At block 2116, when the transmission of the LoLat downlink data has completed (and optionally after the guard time 1906), the regular slave entity (i.e., regular user 1902) may resume its regular uplink data transmission on the primary TDD component carrier. Accordingly, at block 2118, the scheduling entity 1902 may resume using the long TTI to receive regular uplink data from the one or more slave entities on the primary TDD component carrier.

By using the above scheme of pairing the primary TDD component carrier with the secondary TDD component carrier, the thin LoLat grant channel 1912 enables the scheduling entity to quickly and dynamically control the multiplexing of uplink data and downlink data of at least two different data types or categories from a set of slave entities on the primary TDD component carrier.

TDD-TDD carrier pairing: multiplexing LoLat UL on conventional DL

FIG22 shows another example of pairing a primary TDD component carrier with a secondary TDD component carrier, which provides for multiplexing LoLat uplink transmissions (i.e., transmissions from a slave entity) with conventional downlink transmissions (i.e., transmissions from a scheduling entity). In the example shown, the primary TDD component carrier is shown in substantially the same manner as the TDD carrier in FIG8 , where the downlink resources are shown as the scheduling entity sending conventional downlink data to multiple users (slave entities) using a long TTI. Here, as described in further detail below, upon request by the slave entity, the scheduling entity may modify the scheduling assignment or grant of the time-frequency resources, which interrupts the ongoing downlink transmission on the primary TDD component carrier to enable uplink transmission (e.g., LoLat data transmission) on the primary TDD component carrier.

In the example shown, control channels for controlling data carried on the primary TDD component carrier can be carried on either or both of the primary TDD component carrier and/or the secondary TDD component carrier. For example, as shown, the primary TDD component carrier includes a LoLat grant channel 2212 that the slave entity can use to receive information such as a LoLat uplink grant 2214, wherein the LoLat uplink grant 2214 can carry grant information for a LoLat user 2204 that has requested LoLat scheduling for sending a LoLat uplink transmission. The primary TDD component carrier also includes a thin control channel 2216 that can carry a downlink grant modification 2218, wherein the downlink grant modification 2218 is used to modify the downlink time-frequency resource grant corresponding to downlink data reception of a regular user 2202 on the primary TDD component carrier.

In this view, the LoLat grant 2214 is shown as occupying a wider bandwidth than the DL grant modification 2218. This means that while the DL grant modification 2218 may be just a few bits indicating the frequency resources and a number of short TTIs that are reallocated away from the regular user 2202, the LoLat grant 2214 may include more precise information about the LoLat resource assignment, such as user ID, assignment information, modulation and coding scheme, etc.

In addition, a control channel for enabling the slave entity to quickly send information to the scheduling entity is carried on the secondary TDD component carrier. That is, the secondary TDD component carrier includes a thin feedback channel 2208, where the scheduling entity can receive feedback information such as LoLat scheduling request 2210 from the slave entity.

In addition to the channels shown, time-frequency resources corresponding to a long TTI can be granted to one or more slave entities (e.g., users A-F) for downlink transmissions on the primary TDD component carrier using any suitable downlink grant channel (not necessarily one of the channels shown). Since these downlink transmissions are ongoing, if a particular slave entity, designated as a LoLat user 2204, wishes to request resources for a LoLat uplink transmission, it can send a LoLat scheduling request 2210 on a thin feedback channel 2208 on a secondary TDD component carrier. Here, the LoLat scheduling request 2210 can use a short TTI, but this is not always the case. In response, if the scheduling entity wishes to grant the requested LoLat resources, the scheduling entity 102 can send a LoLat grant 2214 on the primary TDD component carrier, which informs the LoLat user 2204 that sent the LoLat user scheduling request 2210 of its granted resources. After an appropriate delay to allow the LoLat user to receive and process the LoLat grant 2214 and prepare its LoLat uplink transmission, the scheduling entity may also send a downlink grant modification 2218 on a thin control channel 2216, which informs the regular users 2202 receiving downlink data transmissions on the primary TDD component carrier that some or all of their granted resources are being modified or removed to make way for the LoLat transmission.

Since the data carrier is a TDD carrier, downlink data transmission using a long TTI to the regular user 2202 is punctured, stopped, or paused during the time when the LoLat user 2204 is transmitting uplink data. During this time, the LoLat user 2204 can transmit its LoLat uplink transmission on the primary TDD component carrier, resulting in an orthogonal multiple access scheme between the regular downlink transmission and the LoLat uplink transmission on the primary TDD component carrier.

In some examples, the scheduling entity may suspend its regular downlink data transmission on the primary TDD component carrier just before the scheduled start of the LoLat uplink transmission. That is, when multiplexing LoLat uplink transmission and regular downlink transmission on the primary TDD component carrier, a gap or guard time 2206 may be optionally used. Here, the guard time 2206 may, for example, compensate for any propagation delay or other air interface delay, which allows the regular downlink transmission to all users in the service area to be fully completed before the start of the LoLat uplink transmission on the primary TDD component carrier.

In this view, downlink grant modification 2218 is shown to occur at the same time as modifying downlink resources. As described above, since the receiving conventional UE 2202 can buffer and post-process downlink grant modification 2218 and downlink data, the need to advance the timing of the grant modification can be avoided.

Figure 23 is a call flow diagram illustrating an exemplary resource assignment and reassignment process that may occur according to an example, for multiplexing uplink data and downlink data with different delay targets using a set of paired primary TDD component carriers and secondary TDD component carriers. In this view, time moves forward in a downward direction, and the communication signals between the entities shown are marked using arrows between the lines below the corresponding entities. As shown, the scheduling entity 2201 communicates with a plurality of subordinate entities 104 including regular users 2202 and LoLat users 2204. Each entity 2201, 2202 and 2204 is configured to communicate on the primary TDD component carrier and the secondary TDD component carrier. The corresponding primary TDD component carrier and the secondary TDD component carrier are schematically illustrated using two vertical lines extending downward from each corresponding entity.

FIG23 is described below in conjunction with the flowchart shown in FIG24. That is, FIG24 is a flowchart illustrating an exemplary process 2400 for resource assignment and reassignment using a set of paired primary TDD component carriers and secondary TDD carriers according to some aspects of the present disclosure. Process 2400 is described from the perspective of scheduling entity 2201, and thus, as described in conjunction with FIG23, it can be operated at the scheduling entity 102 described above in conjunction with FIG1 and/or FIG2. In other examples falling within the scope of the present disclosure, process 2400 can be operated by a general-purpose processor, the processing system 214 described above and shown in FIG2, or any suitable unit for performing the described functions. The specific order of steps or blocks shown in FIG24 is merely exemplary in nature, and in various aspects of the present disclosure, these steps or blocks can occur in any suitable order, with some examples including two or more steps or blocks occurring simultaneously.

At block 2402, the scheduling entity 2201 may send a first assignment or grant 2220 of time-frequency resources to at least one slave entity on a secondary TDD component carrier. Any suitable control channel on the secondary TDD component carrier (or, in some examples, on the primary synchronization TDD component carrier) (e.g., a downlink assignment channel) may be used for the first resource assignment 2220. Here, the first resource assignment 2220 may be configured to indicate which time-frequency resource(s) are allocated to the respective slave entities for receiving regular transmissions of downlink data, i.e., transmissions using a long time-to-transmit (TTI). Based on the first resource assignment 2220, at block 2404, the scheduling entity 2201 may send regular downlink data 2222 to at least one slave entity (e.g., slave entities 2202 and 2204) on the primary TDD component carrier using a long time-to-transmit (TTI). Here, referring to FIG. 22 , the regular downlink data 2222 may correspond to a downlink transmission to a regular user 2202. As shown in FIG23 with dashed arrows, regular downlink data 2222 may optionally be sent to the second slave entity 2204 depending on the contents of the first resource assignment 2220 and whether the second slave entity 2204 is configured to receive downlink data transmissions using a long TTI.

Blocks 2402 and 2404 may be repeated, or iterated multiple times in various examples, as regular downlink data 2222 may continue to be sent to the slave entity. However, at any given time, it may occur that the slave entity 2204 (i.e., LotLat user 2204) may wish to send LoLat uplink data to the scheduling entity 2201. Therefore, at block 2406, the scheduling entity 2201 may receive a LoLat scheduling request 2210 from the LoLat user 2204 (i.e., the second slave entity 2204) on a thin feedback channel 2208 on a secondary TDD component carrier. The LoLat scheduling request 2210 may include information identifying the requesting slave entity 2204 and any relevant information related to the LoLat data desired to be sent.

At block 2408, the scheduling entity 2201 may send a second assignment or grant 2214 of time-frequency resources to the requesting slave entity 2204 on a LoLat grant channel 2212 on the primary TDD component carrier. Here, the second resource assignment 2214 may include information identifying the requesting slave entity 2204 and information identifying the time-frequency resources granted on the TDD uplink carrier for LoLat uplink transmission.

At optional block 2410, the scheduling entity 2201 may suspend its regular downlink data transmission 2222 on the primary TDD component carrier before the scheduled start time of the LoLat uplink transmission 2224. That is, when the LoLat uplink transmission 2224 and the regular downlink transmission 2222 are multiplexed on the primary TDD component carrier, a gap or guard time 2206 may optionally be used.

At block 2412, the scheduling entity 2201 may send a downlink scheduling grant modification 2218 on a thin control channel 2216 on the primary TDD component carrier. Here, the downlink scheduling grant modification 2218 may instruct a regular user, such as the first slave entity 2202, which has granted time-frequency resources for long TTI downlink transmission, to ignore any uplink transmission during at least one designated short TTI. In other words, since the transmission during the TTI is a LoLat uplink transmission 2224 from the LoLat user 2204, rather than for the regular user 2202, the data may not be decoded by the regular user 2202 and may be ignored by the regular user 2202 during post-processing of the corresponding long TTI.

Block 2414 represents operations at one or more slave entities (e.g., LoLat user 2204). That is, in response to the second resource assignment 2214, the LoLat user (i.e., the second slave entity 2204) may transmit LoLat uplink data 2224 using the assigned time-frequency resources on the primary TDD component carrier.

In some examples, the transmission of the downlink scheduling grant modification 2218 at block 2412 and the transmission of the LoLat uplink data 2224 on the primary TDD component carrier at block 2414 (and the corresponding suspension of downlink data on the primary TDD component carrier, excluding any guard time that may be added) can occur simultaneously. While this may violate orthogonality, the regular user can be suitably configured to ignore information corresponding to the time-frequency resources allocated to the LoLat user 2204 during post-processing, as indicated in the downlink grant modification 2218. In other examples, depending on the details of the specific implementation, these transmissions can be at different times. That is, the regular user 2202 can be configured to buffer or cache the content of the thin control channel 2216 and the primary TDD component carrier so that the regular user 2202 can perform an operation to ignore the data during a specified short TTI during post-processing.

At block 2416, the scheduling entity 2201 may receive LoLat uplink data 2224 sent from the requesting slave entity 2204 using short TTIs on the primary TDD component carrier. At block 2418, the scheduling entity 2201 may resume using long TTIs to send regular downlink data 2222 to one or more slave entities (e.g., regular users 2202) on the primary TDD component carrier.

By using the above scheme of pairing the primary TDD component carrier and the secondary TDD component carrier, the thin control channel 2216 and the thin feedback channel 2208 can enable the scheduling entity to multiplex uplink data and downlink data for a set of subordinate entities having at least two different data types or categories.

25, a flow chart illustrating an exemplary process 2500 for wireless communication using a TDD carrier paired with a second carrier and multiplexing long TTIs with short TTIs according to aspects of the present disclosure is provided. In various examples, process 2500 can be implemented by the scheduling entity 102 shown in FIG1 and FIG2; the scheduling entities 501, 801, 1101, 1601, 1901, or 2201 shown in FIG5, 8, 11, 16, 19, and 22, respectively; the processing system 214 including the processor 204; or any suitable means for performing the described functions.

At block 2502, the scheduling entity 102 may wirelessly communicate with one or more slave entities 104 using a first (e.g., long) TTI on a TDD carrier. Here, wirelessly communicating may include sending and/or receiving data and/or control information on one or more communication channels, as described above. Furthermore, at block 2504, the scheduling entity 102 may wirelessly communicate using a second (e.g., short) TTI that at least partially overlaps the long TTI using a second carrier that is paired with the first carrier but spaced apart in frequency from the first carrier. Here, the second, paired carrier may be an FDD carrier or a TDD carrier.

26, a flow chart illustrating an exemplary process 2600 for wireless communication using a pair of TDD carriers for full-duplex communication according to aspects of the present disclosure is provided. In various examples, process 2600 can be implemented by the scheduling entity 102 shown in FIG1 and FIG2; the scheduling entity 501, 801, 1101, 1601, 1901, or 2201 shown in FIG5, 8, 11, 16, 19, and 22, respectively; the processing system 214 including the processor 204; or any suitable means for performing the described functions.

At block 2602, the scheduling entity 102 may communicate wirelessly on a first TDD carrier. Here, communicating wirelessly may include sending and/or receiving data and/or control information on one or more communication channels, as described above. Additionally, at block 2604, the scheduling entity 102 may communicate wirelessly on a second TDD carrier that is paired with the first TDD carrier but spaced apart in frequency from the first TDD carrier. Here, at least a portion of the time slots in the first TDD carrier may be complementary in direction to the time slots in the second TDD carrier that are time-aligned. That is, at least one uplink time slot in the first TDD carrier is time-aligned with a downlink time slot in the second TDD carrier.

As will be readily appreciated by those skilled in the art, the various aspects described throughout this disclosure may be extended to any appropriate telecommunication system, network architecture, and communication standard. For example, the various aspects may be applied to UMTS systems such as W-CDMA, TD-SCDMA, and TD-CDMA. The various aspects may also be applied to systems employing Long Term Evolution (LTE) (with FDD, TDD, or both), LTE-Advanced (LTE-A) (with FDD, TDD, or both), CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB), Bluetooth, and/or other appropriate systems, including those described by yet-to-be-determined wide area network standards. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

Within this disclosure, the word "exemplary" is used to mean "serving as an example, instance, or illustration." Any embodiment or aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term "aspect" does not require that all aspects of the disclosure include the discussed feature, advantage, or mode of operation. The term "coupled" is used herein to refer to a direct or indirect coupling between two objects. For example, if object A physically contacts object B, and object B contacts object C, then object A and object C can still be considered to be coupled to each other even though they are not in direct physical contact with each other. For example, in a package, a first die can be coupled to a second die even though the first die has never been in direct physical contact with the second die. The terms "circuit" and "circuitry" are used broadly and are intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in this disclosure (without limitation as to the type of electronic circuitry), and software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in this disclosure.

One or more of the components, steps, features, and/or functions shown in Figures 1-26 may be rearranged and/or combined into a single component, step, feature, or function, or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from the novel features disclosed herein. The devices, equipment, and/or components shown in Figures 1-26 may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented using software and/or embedded in hardware.

It should be understood that the specific order or hierarchy of steps in the disclosed methods is an illustration of an exemplary process. It should be understood that the specific order or hierarchy of steps in these methods may be rearranged based on design preferences. The accompanying method claims present elements of the various steps in a sample order, but are not meant to be limited to the specific order or hierarchy presented unless explicitly recited therein.

The preceding description is provided to enable anyone skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may also be applied to other aspects. Accordingly, the claims are not intended to be limited to the aspects shown herein, but rather to be consistent with the full scope of claim language, wherein, unless otherwise stated, a reference to an element in the singular is not intended to mean "one and only one," but rather "one or more." Unless otherwise stated, the term "some" refers to one or more. Phrases referring to "at least one" of a list of items refer to any combination of those items, including individual members. For example, "at least one of a, b, or c" is intended to cover: a; b; c; a and b; a and c; b and c; and a, b, and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, no disclosure herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recited in the claims. No claim element shall be construed under 112(6) of the United States Patent Act unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for”.

Claims (88)

1. A method for wireless communication operable at a dependent entity, comprising: On a first carrier, wireless communication is conducted with the scheduling entity using a first transmission time interval (TTI), wherein the first carrier is a time-division duplex (TDD) carrier; and On a second carrier that is paired with the first carrier but frequency-spaced from the first carrier, a second TTI that is different from the first TTI and at least partially overlaps with the first TTI is used to communicate wirelessly with the scheduling entity. 2. The method of claim 1, wherein the second TTI is shorter in duration than the first TTI. 3. The method of claim 1, wherein the second carrier includes at least one control channel for controlling data transmission on the first carrier. 4. The method according to claim 3, wherein the second carrier is a frequency division duplex (FDD) carrier. 5. The method according to claim 4, further comprising: On the feedback channel of the FDD carrier, a scheduling request is sent to the scheduling entity; On the FDD carrier, an uplink grant in response to the scheduling request is received from the scheduling entity, the uplink grant being configured to identify resources on the TDD carrier for uplink data transmission using the second TTI; and Based on the uplink grant, the uplink data is sent to the scheduling entity using the second TTI. 6. The method according to claim 4, further comprising: On the FDD carrier, an authorization modification is received from the scheduling entity, the authorization modification being configured to modify an existing authorization for resources used for uplink data transmission using the first TTI; and According to the permitted modification, zero input is driven to the power amplifier associated with the transceiver to suspend uplink transmission. 7. The method according to claim 4, further comprising: Using the second TTI, downlink permission is received from the scheduling entity on the permission channel on the FDD carrier; and Using the second TTI, downlink data corresponding to the downlink grant is received from the scheduling entity on the TDD carrier. 8. The method of claim 7, wherein the downlink grant and the downlink data corresponding to the downlink grant are received simultaneously with each other. 9. The method according to claim 4, further comprising: While transmitting uplink data on the TDD carrier, the second TTI is used to receive downlink permission from the scheduling entity and buffer it on the permission channel on the FDD carrier. 10. The method of claim 4, further comprising: On the FDD carrier, an authorization modification is received from the scheduling entity, the authorization modification being configured to modify an existing authorization for resources used for downlink data in the first TTI; and Based on the approved modification, the reception of the downlink data using the first TTI on the TDD carrier is modified. 11. The method of claim 10, wherein modifying the reception of the downlink data comprises: suspending the reception of the downlink data during at least one second TTI. 12. The method of claim 1, wherein the second carrier is a TDD carrier having a conjugate pairing with the first carrier, wherein at least a portion of the time slots in the first carrier are directionally complementary to the time slots in the second carrier that are time-aligned. 13. The method of claim 12, further comprising: On the feedback channel of the first carrier, a scheduling request is sent to the scheduling entity; On the second carrier, an uplink grant in response to the scheduling request is received from the scheduling entity, the uplink grant being configured to identify resources on the first carrier for uplink data transmission using the second TTI; and Based on the uplink grant, the uplink data is sent to the scheduling entity using the second TTI. 14. The method of claim 12, further comprising: Receive an authorization modification on the second carrier, the authorization modification being configured to modify an existing authorization for resources used for uplink data transmission using the first TTI; and Based on the approved modification, the uplink data transmission is modified. 15. The method of claim 14, wherein modifying the uplink data comprises: suspending the transmission of the uplink data. 16. The method of claim 12, further comprising: Using the second TTI, downlink permission is received from the scheduling entity on the permission channel of the second carrier; and Using the second TTI, downlink data corresponding to the downlink grant is received from the scheduling entity on the first carrier. 17. The method of claim 16, wherein the downlink grant and the downlink data are received simultaneously with each other. 18. The method of claim 12, further comprising: While transmitting uplink data on the first carrier using the first TTI, the downlink permission is received from the scheduling entity and buffered using the second TTI on the permission channel of the second carrier. 19. The method of claim 12, further comprising: On the feedback channel of the second carrier, a scheduling request is sent to the scheduling entity; Receive from the scheduling entity an uplink grant in response to the scheduling request, the uplink grant being configured to identify resources on the first carrier for uplink data transmission using the second TTI; and Based on the uplink permission, the uplink data is transmitted to the scheduling entity on the first carrier using the second TTI. 20. The method of claim 12, further comprising: On the first carrier, an authorization modification is received from the scheduling entity, the authorization modification being configured to modify an existing authorization for resources used for downlink data in the first TTI; and Based on the approved modification, the reception of the downlink data using the first TTI on the second carrier is modified. 21. The method of claim 20, wherein the granting of modification and the downlink data are received simultaneously with each other. 22. The method of claim 20, wherein modifying the reception of the downlink data comprises: pausing the reception of the downlink data during at least one second TTI. 23. A subordinate entity configured for wireless communication, comprising: At least one processor; A computer-readable medium communicatively coupled to the at least one processor; and A transceiver, communicatively coupled to the at least one processor, Wherein, the at least one processor is configured to: The transceiver is used to wirelessly communicate with a scheduling entity on a first carrier using a first transmission time interval (TTI), wherein the first carrier is a time-division duplex (TDD) carrier; and The transceiver is used to wirelessly communicate with the scheduling entity on a second carrier that is paired with the first carrier but frequency-spaced from the first carrier, using a second TTI that is different from the first TTI and at least partially overlaps with the first TTI. 24. The dependent entity of claim 23, wherein the second TTI is shorter in duration than the first TTI. 25. The dependent entity of claim 23, wherein the second carrier includes at least one control channel for controlling data transmission on the first carrier. 26. The dependent entity according to claim 23, wherein the second carrier is a frequency division duplex (FDD) carrier. 27. The dependent entity of claim 26, wherein the at least one processor is further configured to: The transceiver is used to send a scheduling request to the scheduling entity on the feedback channel on the FDD carrier; Using the transceiver to receive, on the FDD carrier, an uplink grant in response to the scheduling request from the scheduling entity, the uplink grant being configured to identify resources on the TDD carrier for uplink data transmission using the second TTI; and The transceiver is used to send the uplink data to the scheduling entity using the second TTI, based on the uplink grant. 28. The dependent entity of claim 26, wherein the at least one processor is further configured to: The transceiver is used to receive an authorization modification from the scheduling entity on the FDD carrier, the authorization modification being configured to modify an existing authorization for resources used for uplink data transmission using the first TTI; and According to the permitted modification, zero input is driven to the power amplifier associated with the transceiver to suspend uplink transmission. 29. The dependent entity of claim 26, wherein the at least one processor is further configured to: Using the transceiver to receive downlink permission from the scheduling entity on the permission channel on the FDD carrier using the second TTI; and Using the transceiver to use the second TTI, on the TDD carrier, receive downlink data from the scheduling entity corresponding to the downlink grant. 30. The dependent entity of claim 29, wherein the downlink grant and the downlink data corresponding to the downlink grant are received simultaneously with each other. 31. The dependent entity according to claim 26, wherein the at least one processor is further configured to: Using the transceiver to receive downlink permission from the scheduling entity on the permission channel on the FDD carrier using the second TTI; and While transmitting uplink data on the TDD carrier, the downlink permission is buffered. 32. The dependent entity of claim 26, wherein the at least one processor is further configured to: Using the transceiver to receive an authorization modification from the scheduling entity on the FDD carrier, the authorization modification being configured to modify an existing authorization for resources used for downlink data of the first TTI; and Based on the approved modification, the reception of the downlink data using the first TTI on the TDD carrier is modified. 33. The dependent entity of claim 32, wherein the at least one processor configured to modify the reception of the downlink data is further configured to: During at least one second TTI, the reception of the downlink data is suspended. 34. The dependent entity of claim 23, wherein the second carrier is a TDD carrier having a conjugate pair with the first carrier, wherein at least a portion of the time slots in the first carrier are directionally complementary to the time slots in the second carrier that are time-aligned. 35. The dependent entity of claim 34, wherein the at least one processor is further configured to: The transceiver is used to send a scheduling request to the scheduling entity on the feedback channel on the first carrier; Using the transceiver to receive, on the second carrier, an uplink grant in response to the scheduling request from the scheduling entity, the uplink grant being configured to identify resources on the first carrier for uplink data transmission using the second TTI; and The transceiver is used to send the uplink data to the scheduling entity using the second TTI, based on the uplink grant. 36. The dependent entity of claim 34, wherein the at least one processor is further configured to: The transceiver is used to receive an authorization modification on the second carrier, the authorization modification being configured to modify an existing authorization for resources used for uplink data transmission using the first TTI; and Based on the approved modification, the uplink data transmission is modified. 37. The dependent entity of claim 36, wherein the at least one processor configured to modify the uplink data is further configured to: suspend the transmission of the uplink data. 38. The dependent entity according to claim 34, wherein the at least one processor is further configured to: Using the transceiver to utilize the second TTI, receiving downlink permission from the scheduling entity on the permission channel of the second carrier; and Using the transceiver to use the second TTI, on the first carrier, receive downlink data from the scheduling entity corresponding to the downlink grant. 39. The dependent entity of claim 38, wherein the at least one processor is further configured to simultaneously receive the downlink grant and the downlink data. 40. The dependent entity of claim 34, wherein the at least one processor is further configured to: Using the transceiver to utilize the second TTI, receiving downlink permission from the scheduling entity on the permission channel of the second carrier; and While transmitting uplink data on the first carrier using the first TTI, the downlink permission is buffered. 41. The dependent entity according to claim 34, wherein the at least one processor is further configured to: The transceiver is used to send a scheduling request to the scheduling entity on the feedback channel on the second carrier; The transceiver is used to receive uplink grants from the scheduling entity in response to the scheduling request, the uplink grants being configured to identify resources on the first carrier for uplink data transmission using the second TTI; and Using the transceiver, the uplink data is transmitted to the scheduling entity on the first carrier using the second TTI, based on the uplink permission. 42. The dependent entity of claim 34, wherein the at least one processor is further configured to: Using the transceiver to receive, on the first carrier, an authorization modification from the scheduling entity, the authorization modification being configured to modify an existing authorization for resources used for downlink data of the first TTI; and The transceiver is used to modify the reception of the downlink data using the first TTI on the second carrier, according to the permitted modification. 43. The dependent entity of claim 42, wherein the at least one processor is further configured to simultaneously receive the granted modification and the downlink data. 44. The dependent entity of claim 42, wherein the at least one processor configured to modify the reception of the downlink data is further configured to: suspend the reception of the downlink data during at least one second TTI. 45. A subordinate entity configured for wireless communication, comprising: A unit for wirelessly communicating with a scheduling entity on a first carrier using a first transmission time interval (TTI), wherein the first carrier is a time-division duplex (TDD) carrier; and A unit for wirelessly communicating with the scheduling entity on a second carrier that is paired with the first carrier but frequency-spaced from the first carrier, using a second TTI that is different from the first TTI and at least partially overlaps with the first TTI. 46. The dependent entity of claim 45, wherein the second TTI is shorter in duration than the first TTI. 47. The dependent entity of claim 45, wherein the second carrier includes at least one control channel for controlling data transmission on the first carrier. 48. The dependent entity according to claim 45, wherein the second carrier is a frequency division duplex (FDD) carrier. 49. The dependent entity according to claim 48, further comprising: A unit for sending a scheduling request to the scheduling entity on the feedback channel of the FDD carrier; A unit for receiving, on the FDD carrier, an uplink grant in response to a scheduling request from the scheduling entity, the uplink grant being configured to identify a resource on the TDD carrier for uplink data transmission using the second TTI; and A unit for sending the uplink data to the scheduling entity using the second TTI based on the uplink grant. 50. The dependent entity according to claim 48, further comprising: A unit for receiving permission modification from the scheduling entity on the FDD carrier, the permission modification being configured to modify an existing permission for resources used for uplink data transmission using the first TTI; and A unit for driving zero input to a power amplifier associated with the transceiver, in accordance with the permitted modification, to suspend uplink transmission. 51. The dependent entity according to claim 48, further comprising: A unit for receiving downlink permission from the scheduling entity on the permission channel on the FDD carrier using the second TTI; and A unit for receiving downlink data corresponding to the downlink grant from the scheduling entity on the TDD carrier using the second TTI. 52. The dependent entity according to claim 48, further comprising: A unit for receiving and buffering downlink permission from the scheduling entity on the permission channel of the FDD carrier while transmitting uplink data on the TDD carrier using the second TTI. 53. The dependent entity according to claim 48, further comprising: A unit for receiving permission modification from the scheduling entity on the FDD carrier, the permission modification being configured to modify an existing permission for resources used for downlink data of the first TTI; and A unit for modifying the reception of downlink data using the first TTI on the TDD carrier according to the approved modification. 54. The dependent entity of claim 53, wherein the unit for receiving the downlink grant and the unit for receiving the downlink data corresponding to the downlink grant are configured to receive the downlink grant and the downlink data simultaneously with each other. 55. The dependent entity of claim 53, wherein the unit for modifying the reception of the downlink data is configured to: suspend the reception of the downlink data during at least one second TTI. 56. The dependent entity of claim 45, wherein the second carrier is a TDD carrier having a conjugate pair with the first carrier, wherein at least a portion of the time slots in the first carrier are directionally complementary to the time slots in the second carrier that are time-aligned. 57. The dependent entity according to claim 56, further comprising: A unit for sending a scheduling request to a scheduling entity on a feedback channel on the first carrier; A unit for receiving, on the second carrier, an uplink grant in response to a scheduling request from the scheduling entity, the uplink grant being configured to identify a resource on the first carrier for uplink data transmission using the second TTI; and A unit for sending the uplink data to the scheduling entity using the second TTI based on the uplink grant. 58. The dependent entity according to claim 56, further comprising: A unit for receiving permission modification on the second carrier, the permission modification being configured to modify an existing permission for resources used for uplink data transmission using the first TTI; and A unit for modifying the uplink data transmission according to the approved modification. 59. The dependent entity according to claim 58, wherein the unit for modifying the uplink data transmission is configured to: suspend the uplink data transmission. 60. The dependent entity according to claim 56, further comprising: A unit for receiving downlink permission from a scheduling entity on a permission channel on the second carrier using the second TTI; and A unit for receiving downlink data corresponding to the downlink grant from the scheduling entity on the first carrier using the second TTI. 61. The dependent entity of claim 60, wherein the unit for receiving the downlink grant and the unit for receiving the downlink data are configured to receive the downlink grant and the downlink data simultaneously with each other. 62. The dependent entity according to claim 56, further comprising: A unit for receiving and buffering downlink permission from a scheduling entity on a permission channel on a second carrier while simultaneously transmitting uplink data on the first carrier using the first TTI and using the second TTI. 63. The dependent entity according to claim 56, further comprising: A unit for sending a scheduling request to a scheduling entity on a feedback channel on the second carrier; A unit for receiving uplink grants in response to the scheduling request from the scheduling entity, the uplink grants being configured to identify resources on the first carrier for uplink data transmission using the second TTI; and A unit for transmitting uplink data to the scheduling entity on the first carrier using the second TTI, based on the uplink permission. 64. The dependent entity according to claim 56, further comprising: A unit for receiving, on the first carrier, an authorization modification from the scheduling entity, the authorization modification being configured to modify an existing authorization for resources used for downlink data of the first TTI; and A unit for modifying the reception of downlink data on the second carrier using the first TTI, based on the approved modification. 65. The dependent entity of claim 64, wherein the unit for receiving the permission to modify and the unit for receiving the downlink data are configured to receive the permission to modify and the downlink data simultaneously with each other. 66. The dependent entity of claim 64, wherein the unit for modifying the reception of the downlink data is configured to: suspend the reception of the downlink data during at least one second TTI. 67. A computer-readable medium storing computer-executable code and located at a subordinate entity configured for wireless communication, comprising: Instructions for enabling a computer to wirelessly communicate with a scheduling entity on a first carrier using a first transmission time interval (TTI), wherein the first carrier is a time-division duplex (TDD) carrier; and Instructions for enabling a computer to wirelessly communicate with the scheduling entity on a second carrier that is paired with the first carrier but frequency-spaced from the first carrier, using a second TTI that is different from and at least partially overlaps with the first TTI. 68. The computer-readable medium of claim 67, wherein the second TTI is shorter in duration than the first TTI. 69. The computer-readable medium of claim 67, wherein the second carrier includes at least one control channel for controlling data transmission on the first carrier. 70. The computer-readable medium of claim 69, wherein the second carrier is a frequency division duplex (FDD) carrier. 71. The computer-readable medium of claim 70, further comprising: Instructions for enabling the computer to send a scheduling request to the scheduling entity on the feedback channel of the FDD carrier; This instruction is used to enable a computer to receive, on the FDD carrier, an uplink grant from the scheduling entity in response to the scheduling request, the uplink grant being configured to identify resources on the TDD carrier for uplink data transmission using the second TTI; and Instructions are used to enable the computer to send the uplink data to the scheduling entity using the second TTI, based on the uplink permission. 72. The computer-readable medium of claim 70, further comprising: This is used to enable a computer to receive, on the FDD carrier, an instruction for permission modification from the scheduling entity, the permission modification being configured to modify an existing permission for resources used for uplink data transmission using the first TTI; and Instructions for causing a computer, based on the permitted modification, to drive zero input to a power amplifier associated with the transceiver to suspend uplink transmission. 73. The computer-readable medium of claim 70, further comprising: For enabling the computer to use the second TTI, on the grant channel on the FDD carrier, to receive a downlink grant instruction from the scheduling entity; and Instructions for enabling a computer to use the second TTI, on the TDD carrier, to receive downlink data corresponding to the downlink grant from the scheduling entity. 74. The computer-readable medium of claim 73, wherein the instructions for causing the computer to receive downlink grant and the instructions for causing the computer to receive downlink data corresponding to the downlink grant are configured to receive the downlink grant and the downlink data simultaneously with each other. 75. The computer-readable medium of claim 70, further comprising: This is used to enable the computer to transmit uplink data on the TDD carrier while simultaneously using the second TTI to receive downlink grant and buffer instructions from the scheduling entity on the grant channel of the FDD carrier. 76. The computer-readable medium of claim 70, further comprising: This is used to enable a computer to receive, on the FDD carrier, an instruction for permission modification from the scheduling entity, the permission modification being configured to modify an existing permission for resources used for downlink data of the first TTI; and Instructions for causing a computer to modify the reception of downlink data using the first TTI on the TDD carrier, based on the approved modification. 77. The computer-readable medium of claim 76, wherein the instruction for causing the computer to modify the reception of the downlink data is further configured to: suspend the reception of the downlink data during at least one second TTI. 78. The computer-readable medium of claim 67, wherein the second carrier is a TDD carrier having a conjugate pairing with the first carrier, wherein at least a portion of the time slots in the first carrier are directionally complementary to the time slots in the second carrier that are time-aligned. 79. The computer-readable medium of claim 78, further comprising: Instructions used to enable the computer to send a scheduling request to the scheduling entity on the feedback channel of the first carrier. Instructions are provided to enable a computer to receive, on the second carrier, an uplink grant from the scheduling entity in response to the scheduling request, the uplink grant being configured to identify resources on the first carrier for uplink data transmission using the second TTI; and Instructions are used to enable the computer to send the uplink data to the scheduling entity using the second TTI, based on the uplink permission. 80. The computer-readable medium of claim 78, further comprising: For enabling a computer to receive an instruction for permission modification on the second carrier, the permission modification being configured to modify an existing permission for resources used for uplink data transmission using the first TTI; and Instructions for causing the computer to modify the uplink data transmission in accordance with the approved modification. 81. The computer-readable medium of claim 80, wherein the instruction for causing the computer to modify the uplink data is further configured to: suspend the transmission of the uplink data. 82. The computer-readable medium of claim 78, further comprising: Used to enable a computer to receive downlink grant instructions from a scheduling entity on the grant channel of the second carrier, using the second TTI; and Instructions for enabling a computer to use the second TTI, on the first carrier, to receive downlink data corresponding to the downlink grant from the scheduling entity. 83. The computer-readable medium of claim 82, wherein the instructions for enabling the computer to receive downlink grant and the instructions for enabling the computer to receive downlink data are configured to receive the downlink grant and the downlink data simultaneously with each other. 84. The computer-readable medium of claim 78, further comprising: This is used to enable a computer to receive downlink grant and buffer instructions from a scheduling entity on the grant channel of the second carrier while simultaneously transmitting uplink data on the first carrier using the first TTI. 85. The computer-readable medium of claim 78, further comprising: Instructions used to enable the computer to send a scheduling request to the scheduling entity on the feedback channel of the second carrier; Instructions are used to enable a computer to receive uplink permission from the scheduling entity in response to the scheduling request, the uplink permission being configured to identify resources on the first carrier for uplink data transmission using the second TTI; and Instructions are used to enable a computer to send the uplink data to the scheduling entity on the first carrier using the second TTI, based on the uplink permission. 86. The computer-readable medium of claim 85, wherein the instructions for causing the computer to receive the permission to modify and the instructions for causing the computer to receive downlink data are configured to receive the permission to modify and the downlink data simultaneously with each other. 87. The computer-readable medium of claim 78, further comprising: For enabling a computer to receive, on the first carrier, an instruction for permission modification from the scheduling entity, the permission modification being configured to modify an existing permission for resources used for downlink data of the first TTI; and Instructions for causing a computer to modify the reception of downlink data using the first TTI on the second carrier, based on the permitted modification. 88. The computer-readable medium of claim 87, wherein the instruction for causing the computer to modify the reception of the downlink data is further configured to: suspend the reception of the downlink data during at least one second TTI.