Method and apparatus for uplink transmission in a time division duplex subframe

Abstract

Various aspects of the present disclosure provide methods, apparatus, and computer software for transmitting a common uplink burst in a time division duplex (TDD) carrier. The common uplink burst includes a sounding reference signal (SRS) transmitted separately from (e.g., decoupled from) a demodulation reference signal (DM-RS). At least one symbol in the common uplink burst includes a control region for carrying control information and a data region for carrying data information. The SRS may be precoded separately from the precoding of the control region and the data region so that the control information and / or data information may be transmitted using multiple input multiple output (MIMO).

Description

[0001] This application is a divisional application of Chinese invention patent application 201680071831.5 (PCT / US2016 / 064837), filed on December 2, 2016, entitled “Method and apparatus for uplink transmission in time division duplex subframe”. Technical Field

[0002] Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to a channel structure for uplink transmissions in a time division duplex (TDD) subframe. Background Art

[0003] Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcast, etc. Such networks, which are typically multiple-access networks, support communications for multiple users by sharing the available network resources.

[0004] Within such wireless networks, a variety of data services can be provided, including voice, video, and email. More recently, wireless communication networks are being used for an even wider range of services, including mission-critical applications and remote control applications (such as remote surgery, where real-time feedback is necessary). In such applications, very low latency is critical to being able to achieve a suitably high quality of service. That is, the time to transmit information from a communication device and receive a response at the communication device may need to be extremely fast, on the order of milliseconds.

[0005] As the demand for mobile broadband access continues to grow, research and development continues to advance wireless communication 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

[0006] A brief summary of one or more aspects of the present disclosure is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived features of the present disclosure, and is neither intended to identify the key or decisive elements of all aspects of the present disclosure nor to attempt to define the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in a simplified form as a preface to a more detailed description given later.

[0007] Various aspects of the present disclosure provide methods, apparatus, and computer software for wireless communications using common uplink bursts by employing a decoupled mode.

[0008] One aspect of the present disclosure provides a method for wireless communication on a time division duplex (TDD) carrier that can be operated at a subordinate entity. According to the method, the subordinate entity transmits an uplink burst in a downlink centric subframe and an uplink centric subframe on the TDD carrier. The uplink burst includes a first symbol and a second symbol. The first symbol includes a sounding reference signal (SRS) configured to enable sounding of the TDD carrier. The second symbol includes an information bit and a demodulation reference signal (DM-RS). The DM-RS is configured to enable demodulation of the information bit carried in the second symbol.

[0009] Another aspect of the present disclosure provides a subordinate entity configured for wireless communication on a TDD carrier. The subordinate entity includes a processor, a memory communicatively coupled to the processor, and a transceiver communicatively coupled to the processor. The processor and the memory are configured to transmit an uplink burst within a downlink centric subframe and an uplink centric subframe on the TDD carrier. The uplink burst includes a first symbol and a second symbol. The first symbol includes an SRS configured to enable sounding of the TDD carrier. The second symbol includes an information bit and a DM-RS. The DM-RS is configured to enable demodulation of the information bit carried in the second symbol.

[0010] Another aspect of the present disclosure provides a subordinate entity configured for wireless communication on a TDD carrier. The subordinate entity includes a device for transmitting an uplink burst in a downlink centric subframe and an uplink centric subframe on the TDD carrier. The uplink burst includes a first codeword and a second codeword. The first codeword includes an SRS configured to enable sounding of the TDD carrier. The second codeword includes an information bit and a DM-RS. The DM-RS is configured to enable demodulation of the information bit carried in the second codeword.

[0011] These and other aspects of the present invention will be more fully understood after reading the following detailed description. After reading the following description of specific exemplary embodiments of the present invention in conjunction with the accompanying drawings, other aspects, features and embodiments of the present invention will be apparent to those of ordinary skill in the art. Although the features of the present invention may be discussed below with respect to certain embodiments and accompanying 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 embodiments may be discussed as having certain advantageous features, one or more of such features may also be used according to the various embodiments of the present invention discussed herein. In a similar manner, although exemplary embodiments may be discussed below as device, system or method embodiments, it should be appreciated that such exemplary embodiments may be implemented in various devices, systems, and methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of a wireless communication network according to some embodiments of the present disclosure.

[0013] Figure 2 is a schematic block diagram illustrating a scheduling entity in communication with a plurality of subordinate entities according to some embodiments of the present disclosure.

[0014] Figure 3 is a block diagram illustrating an example of a wireless communication device according to some embodiments of the present disclosure.

[0015] Figure 4 is a block diagram illustrating further details of a scheduling entity in communication with subordinate entities according to some embodiments of the present disclosure.

[0016] Figure 5 is a schematic diagram illustrating a downlink-centric subframe and an uplink-centric subframe each including a common uplink burst according to some embodiments of the present disclosure.

[0017] Figure 6 is a schematic diagram illustrating the structure of a common uplink burst in a decoupled mode according to some embodiments of the present disclosure.

[0018] Figure 7 is a schematic diagram illustrating the structure of a common uplink burst in a decoupled mode according to some embodiments of the present disclosure.

[0019] Figure 8 is a signal flow diagram illustrating subordinate entities requesting a scheduling entity to share resources in an uplink (UL) burst according to some embodiments of the present disclosure.

[0020] Fig. 9 is a diagram illustrating a method of operating a subordinate entity for wireless communication on a time division duplex (TDD) carrier according to an aspect of the present disclosure.

[0021] Fig.10 is a diagram illustrating a precoding method of a sounding reference signal (SRS) and a demodulation reference signal (DM-RS) according to an aspect of the present disclosure. DETAILED DESCRIPTION

[0022] 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 configurations in which the concepts described herein may be practiced. This 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 in order to avoid diluting such concepts.

[0023] The various concepts presented throughout this disclosure may be implemented across a wide variety of telecommunication systems, network architectures, and communication standards. Figure 1 , a simplified schematic illustration of access network 100 is provided as an illustrative example and not a limitation.

[0024] The geographic area covered by the access network 100 may be divided into a number of cellular areas (cells), including macro cells 102, 104, and 106, and small cells 108, each of which may include one or more sectors. Cells may be defined geographically (e.g., by coverage area) and / or may be defined according to frequency, scrambling code, etc. In a cell divided into sectors, the multiple sectors within the cell may be formed by antenna groups, where each antenna is responsible for communicating with mobile devices in a portion of the cell.

[0025] Generally speaking, a radio transceiver device serves each cell. The radio transceiver device is often referred to as a base station (BS) in many wireless communication systems, but may also be referred to as a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a Node B, an evolved Node B, or some other suitable terminology by those skilled in the art.

[0026] exist Figure 1 , two high-power base stations 110 and 112 are shown in the cellular cells 102 and 104; and a third high-power base station 114 is shown as controlling a remote radio head (RRH) 116 in the cellular cell 106. In this example, the cellular cells 102, 104, and 106 may be referred to as macro cells because the high-power base stations 110, 112, and 114 support cellular cells with large sizes. In addition, a low-power base station 118 is shown in a small cellular cell 108 (e.g., a micro cell, a micro cell, a femto cell, a home base station, a home node B, a home evolved node B, etc.), which may overlap with one or more macro cells. In this example, the cellular cell 108 may be referred to as a small cellular cell because the low-power base station 118 supports a cellular cell with a relatively small size. Cell size setting can be done according to system design and component constraints. It is to be understood that the access network 100 may include any number of wireless base stations and cellular cells. Base stations 110, 112, 114, 118 provide wireless access points to the core network for any number of mobile devices.

[0027] Figure 1Further included is a quadcopter or drone 120 that can be configured to act as a base station. That is, in some examples, a cell may not necessarily be stationary, and the geographic area of ​​a cell may move depending on the location of a mobile base station (such as a quadcopter 120).

[0028] In some examples, the base stations may be interconnected to each other and / or to one or more other base stations or network nodes (not shown) in access network 100 via various types of backhaul interfaces, such as direct physical connections, virtual networks, or the like using any suitable transport network.

[0029] The access network 100 is illustrated as supporting wireless communications for multiple mobile devices. Although mobile devices are often referred to as user equipment (UE) in standards and specifications promulgated by the Third Generation Partnership Project (3GPP), such devices may also be referred to by those skilled in the art 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 (AT), mobile terminals, wireless terminals, remote terminals, handsets, terminals, user agents, mobile clients, clients, or some other suitable terminology.

[0030] Within this document, a "mobile" device need not have the ability to move, and may be stationary. Some non-limiting examples of mobile devices include mobile stations, cellular (cell) phones, smart phones, Session Initiation Protocol (SIP) phones, laptops, personal computers (PCs), notebooks, netbooks, smartbooks, tablet devices, and personal digital assistants (PDAs). Mobile devices may additionally be "Internet of Things" (IoT) devices, such as automobiles or other transportation vehicles, satellite radios, global positioning system (GPS) devices, logistics controllers, drones, multicopters, quadcopters, smart energy or security devices, solar panels or solar arrays, city lighting, water, or other infrastructure; industrial automation and enterprise devices; consumer and wearable devices, such as glasses, wearable cameras, smart watches, health or fitness trackers, digital audio players (e.g., MP3 players), cameras, game consoles, and the like; and digital home or smart home devices, such as home audio, video, and multimedia devices, appliances, sensors, vending machines, smart lighting, home security systems, smart meters, and the like.

[0031] Within access network 100, cells may include UEs that may be in communication with one or more sectors of each cell. For example, UEs 122 and 124 may be in communication with base station 110; UEs 126 and 128 may be in communication with base station 112; UEs 130 and 132 may be in communication with base station 114 via RRH 116; UE 134 may be in communication with low power base station 118; and UE 136 may be in communication with mobile base station 120. Here, each base station 110, 112, 114, 118, and 120 may be configured to provide an access point to a core network (not shown) for all UEs in the corresponding cell.

[0032] In another example, quadcopter 120 can be configured to function as a UE. For example, quadcopter 120 can operate within cell 102 by communicating with base station 110.

[0033] The air interface in the access network 100 may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of various devices. For example, multiple access for uplink (UL) or reverse link transmissions from the UEs 122 and 124 to the base station 110 may be provided using time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or other suitable multiple access schemes. In addition, multiplexing of downlink (DL) or forward link transmissions from the base station 110 to the UEs 122 and 124 may be provided using time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), or other suitable multiplexing schemes.

[0034] Within the access network 100, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of a signal from its serving cell and various parameters of neighboring cells. In addition, depending on the quality of these parameters, the UE may maintain communication with one or more neighboring cells. During this time, if the UE moves from one cell to another, or if the signal quality from a neighboring cell exceeds the signal quality from the serving cell for a given amount of time, the UE may perform a handover or switch from the serving cell to the neighboring (target) cell. For example, a UE 124 may move from a geographic area corresponding to its serving cell 102 to a geographic area corresponding to a neighboring cell 106. When the signal strength or quality from a neighboring cell 106 exceeds the signal strength or quality of its serving cell 102 for a given amount of time, the UE 124 may transmit a report message indicating this condition to its serving base station 110. In response, the UE 124 may receive a handover command, and the UE may undergo a handover to the cell 106.

[0035] In some examples, access to the air interface may be scheduled, where a scheduling entity (e.g., a base station) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, a scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, the subordinate entities utilize resources allocated by the scheduling entity.

[0036] Base stations are not the only entities that can be used as scheduling entities. That is, in some examples, UEs can be used as scheduling entities, thereby scheduling resources for one or more subordinate entities (e.g., one or more other UEs). For example, UE 138 is illustrated as communicating with UEs 140 and 142. In this example, UE 138 is acting as a scheduling entity, and UEs 140 and 142 utilize resources scheduled by the UE 138 for wireless communication. UEs can act as scheduling entities in peer-to-peer (P2P) networks and / or in mesh networks. In the mesh network example, UEs 140 and 142 can optionally communicate directly with each other in addition to communicating with scheduling entity 138.

[0037] Thus, in a wireless communication network having scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, and a mesh configuration, a scheduling entity and one or more subordinate entities may communicate using the scheduled resources. Figure 2 , the block diagram illustrates a scheduling entity 202 and a plurality of subordinate entities 204. Here, the scheduling entity 202 may correspond to base stations 110, 112, 114, and 118. In additional examples, the scheduling entity 202 may correspond to UE 138, quadcopter 120, or any other suitable node in access network 100. Similarly, in various examples, the subordinate entities 204 may correspond to UEs 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, and 142, or any other suitable node in access network 100.

[0038] like Figure 2As illustrated, the scheduling entity 202 may broadcast data 206 (which may be referred to as downlink data) to one or more subordinate entities 204. According to certain aspects of the present disclosure, the term downlink may refer to a point-to-multipoint transmission originating at the scheduling entity 202. Broadly speaking, the scheduling entity 202 is a node or device responsible for scheduling traffic (including downlink transmissions and, in some examples, uplink data 210 from one or more subordinate entities to the scheduling entity 202) in a wireless communication network. Another way to describe the system may be to use the term broadcast channel multiplexing. According to aspects of the present disclosure, the term uplink may refer to a point-to-point transmission originating at the subordinate entity 204. Broadly speaking, the subordinate entity 204 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 in the wireless communication network (such as the scheduling entity 202).

[0039] The scheduling entity 202 may broadcast a control channel 208 to one or more subordinate entities 204. The uplink data 210 and / or the downlink data 206 may be transmitted using a transmission time interval (TTI). Here, a TTI may correspond to a packaged set of information or a packet that can be independently decoded. In various examples, a TTI may correspond to a frame, a subframe, a data block, a time slot, or other suitable bit grouping for transmission.

[0040] In addition, the lower level entity 204 may transmit uplink control information 212 to the scheduling entity 202. The uplink control information may include a variety of packet types and categories, including pilots, reference signals, and information configured to enable or assist in decoding uplink data transmissions. In some examples, the control information 212 may include a scheduling request (SR), i.e., a request to the scheduling entity 202 to schedule uplink transmissions. Here, in response to the SR transmitted on the control channel 212, the scheduling entity 202 may transmit information in the downlink control channel 208 that may schedule TTIs for uplink packets. In a further example, the uplink control channel 212 may include a hybrid automatic repeat request (HARQ) feedback transmission, such as an acknowledgement (ACK) or a negative acknowledgement (NACK). HARQ is a well-known technology to those of ordinary skill in the art, in which packet transmissions may be checked for accuracy at the receiving side, and if acknowledged, an ACK may be transmitted, and if not acknowledged, a NACK may be transmitted. In response to the NACK, the transmitting device may send a HARQ retransmission, which may implement catch-up combining, incremental redundancy, and the like.

[0041] Figure 2 The channels illustrated in are not necessarily all of the channels that may be utilized between the scheduling entity 202 and the subordinate entity 204, and one of ordinary skill in the art will recognize that other channels may be utilized in addition to those illustrated, such as other data, control, and feedback channels.

[0042] Figure 3 304. 304 is a conceptual diagram illustrating an example of a hardware implementation of a wireless communication device 300 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 with a processing system 314 including one or more processors 304. For example, the wireless communication device 300 may be a scheduling entity 202, a base station (BS) 102, or any other suitable network node, such as in Figure 1 , 2 , 4 and / or 8. In addition, the wireless communication device 300 can be a subordinate entity 204, a UE 126 or 128, an IoE device, or any other suitable network node, such as in Figure 1 , 2 , 4 and / or 8. Examples of processor 304 include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform various functionalities described throughout the present disclosure. That is, the processor 304 as utilized in the wireless communication device 300 can be used to implement any one or more of the processes described in the present disclosure.

[0043] In this example, the processing system 314 can be implemented with a bus architecture generally represented by bus 302. Depending on the specific application and overall design constraints of the processing system 314, the bus 302 may include any number of interconnecting buses and bridges. The bus 302 links together various circuits including one or more processors (generally represented by processor 304), memory 305, and computer-readable media (generally represented by computer-readable media 306). The bus 302 may also link various other circuits, such as timing sources, peripherals, regulators, and power management circuits, which are well known in the art and therefore will not be further described. The bus interface 308 provides an interface between the bus 302 and one or more transceivers 310. The transceiver 310 provides a communication interface or device for communicating with various other equipment on a transmission medium. In various examples, the transceiver 310 may include one or more antennas and may be enabled in a multi-antenna example to determine the angle of arrival of the received signal or for beamforming the transmitted signal. The transceiver 310 may include various subcomponents configured to enable wireless communication, including, but not limited to, one or more power amplifiers, transmitters, receivers, filters, oscillators, etc. In addition, depending on the nature of the device, a user interface 312 (e.g., a keypad, display, speaker, microphone, joystick, etc.) may also be provided.

[0044] In some aspects of the present disclosure, the processor 304 may include a common uplink (UL) burst block 320, which may be configured to perform operations related to Figure 5 –10 for the common UL burst. For example, the common UL burst block 320 may include one or more functional blocks or components, such as a DL centric subframe block 322, a UL centric subframe block 324, a control information block 326, a data information block 328, a demodulation reference signal (DM-RS) block 330, and a sounding reference signal (SRS) block 332. The common UL burst block 320 may be configured by executing code (e.g., a common UL burst communication code stored in the computer readable medium 306).

[0045] The DL centric subframe block 322 may be configured to perform functions for handling DL centric subframe communications: for example, transmitting, receiving, and / or scheduling one or more DL centric subframes 504 (see Figure 5 ). The UL centric subframe block 324 may be configured to perform functions for handling UL centric subframe communications: for example, transmitting, receiving, and / or scheduling one or more UL centric subframes 502 (see Figure 5 ). The control information block 326 may be configured to handle control information, such as transmitting, receiving and / or scheduling a scheduling request (SR), an acknowledgement (ACK) / negative acknowledgement (NACK), and other control signals in a common UL burst. The data information block 328 may be configured to handle data information, such as transmitting, receiving and / or scheduling a physical uplink shared channel (PUSCH) or other user data. The DM-RS block 330 may be configured to perform operations related to Figure 5 The SRS block 332 may be configured to perform functions related to the DM-RS described in relation to FIG. Figure 5 –10 describes the SRS related functions.

[0046] The processor 304 is responsible for managing the bus 302 and general processing, including the execution of software stored on the computer-readable medium 306. The software, when executed by the processor 304, causes the processing system 314 to perform the various functions described below for any particular device. The computer-readable medium 306 may also be used to store data that is manipulated by the processor 304 when executing the software.

[0047] One or more processors 304 in the processing system can execute software. Software should be broadly interpreted to mean instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether described in software, firmware, middleware, microcode, hardware description language, or other terms. The software may reside on a computer-readable medium 306. The computer-readable medium 306 may be a non-transitory computer-readable medium. As examples, non-transitory computer readable media include magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes), optical disks (e.g., compact disks (CDs) or digital versatile disks (DVDs)), smart cards, flash memory devices (e.g., card, stick, or key-type 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 medium for storing software and / or instructions that can be accessed and read by a computer. Computer readable medium 306 may reside in processing system 314, external to processing system 314, or distributed across multiple entities including processing system 314. Computer readable medium 306 may be implemented in a computer program product. As an example, a computer program product may include a computer readable medium in packaging materials. Those skilled in the art will recognize how to best implement the described functionality presented throughout this disclosure depending on the specific application and the overall design constraints imposed on the overall system.

[0048] Figure 4 4 is a block diagram showing additional details of an example of a scheduling entity 202 in an access network in communication with an example of a subordinate entity 204. In the DL, upper layer packets from the core network are provided to the controller / processor 475. The controller / processor 475 implements the functionality of the L2 layer. In the DL, the controller / processor 475 provides header compression, ciphering, packet segmentation and reordering, multiplexing between logical channels and transport channels, and radio resource allocation to the subordinate entity 204 based on various priority metrics. The controller / processor 475 is also responsible for hybrid automatic repeat request (HARQ) operations, retransmission of lost packets, and signaling to the subordinate entity 204.

[0049] The transmit (TX) processor 416 implements various signal processing functions for the L1 layer (i.e., the physical layer). These signal processing functions include coding and interleaving to facilitate forward error correction (FEC) at the lower entity 204 and mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). Subsequently, the coded and modulated symbols are split into parallel streams. Each stream is then mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from the channel estimator 474 can be used to determine the coding and modulation schemes and for spatial processing. The channel estimate may be derived from a reference signal and / or channel condition feedback transmitted by the subordinate entity 204. Each spatial stream may then be provided via a separate transmitter 418TX to a different antenna 420. Each transmitter 418TX may modulate a radio frequency (RF) carrier with a respective spatial stream for transmission.

[0050] At the lower level entity 204, each receiver 454RX receives a signal through its respective antenna 452. Each receiver 454RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 456. The RX processor 456 implements various signal processing functions of the L1 layer. The RX processor 456 may perform spatial processing on the information to recover any spatial stream destined for the lower level entity 204. If there are multiple spatial streams destined for the lower level entity 204, they may be combined into a single OFDM symbol stream by the RX processor 456. The RX processor 456 then transforms the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the signal constellation point most likely to be transmitted by the scheduling entity 202. These soft decisions may be based on channel estimates calculated by the channel estimator 458. These soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the scheduling entity 202. These data and control signals are then provided to the controller / processor 459.

[0051] The controller / processor 459 implements the L2 layer. The controller / processor may be associated with a memory 460 that stores program codes and data. The memory 460 may be referred to as a computer-readable medium. In the UL, the controller / processor 459 provides multiplexing between transport channels and logical channels, packet reassembly, cipher decoding, header decompression, and control signal processing to recover upper layer packets from the core network. These upper layer packets are then provided to a data sink 462, which represents all protocol layers above the L2 layer. Various control signals may also be provided to the data sink 462 for L3 processing. The controller / processor 459 is also responsible for error detection using an acknowledgment (ACK) and / or negative acknowledgment (NACK) protocol to support HARQ operations.

[0052] In the UL, a data source 467 is used to provide upper layer packets to the controller / processor 459. The data source 467 represents all protocol layers above the L2 layer. Similar to the functionality described in conjunction with the DL transmissions performed by the scheduling entity 202, the controller / processor 459 implements the L2 layers of the user plane and the control plane by providing header compression, ciphering, packet segmentation and reordering, and multiplexing between logical channels and transport channels based on radio resource allocations performed by the scheduling entity 202. The controller / processor 459 is also responsible for HARQ operations, retransmission of lost packets, and signaling to the scheduling entity 202.

[0053] Channel estimates derived by the channel estimator 458 from a reference signal or feedback transmitted by the scheduling entity 202 may be used by the TX processor 468 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 468 may be provided to different antennas 452 via separate transmitters 454TX. Each transmitter 454TX may modulate an RF carrier with a respective spatial stream for transmission.

[0054] UL transmissions are processed at the scheduling entity 202 in a manner similar to that described in conjunction with the receiver functionality at the subordinate entity 204. Each receiver 418RX receives a signal through its respective antenna 420. Each receiver 418RX recovers information modulated onto an RF carrier and provides the information to a RX processor 470. The RX processor 470 may implement the L1 layer.

[0055] The controller / processor 475 implements the L2 layer. The controller / processor 475 may be associated with a memory 476 that stores program codes and data. The memory 476 may be referred to as a computer-readable medium. In the UL, the controller / processor 475 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover upper layer packets from the lower entity 204. The upper layer packets from the controller / processor 475 may be provided to the core network. The controller / processor 475 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0056] Common UL bursts on TDD carrier

[0057] In any wireless communication network, two-way communication is a desired feature. Typically, duplexing communications onto air channels is accomplished using frequency division duplexing (FDD) or time division duplexing (TDD). In FDD, a pair of carriers is used, where each respective carrier is used to carry communication signals in different directions. In TDD, unpaired carriers are used. Here, duplexing of uplink and downlink communications is achieved by time-sharing a carrier, where the uplink and downlink communications occupy the carrier at different times.

[0058] In many modern wireless communication networks, a significant portion of the spectrum has been allocated by regulators as FDD paired carriers. For newly developed technologies, if very high bandwidth communications (e.g., 100MHz, 300MHz, or higher) are desired; however, these FDD technologies have already utilized most of the spectrum, and thus may not have as much bandwidth as desired for much higher data rates. At higher frequencies (including but not limited to millimeter wave (mmW) frequencies), TDD carriers may be more available. In addition, such TDD carriers may be less expensive for carriers to obtain the right to use.

[0059] When utilizing a TDD carrier, in some examples communications may be organized by dividing the channels in the time domain into frames, where the frames are further divided into subframes. According to one aspect of the present disclosure, subframes may take at least two general forms, referred to herein as uplink-centric subframe structures and downlink-centric subframe structures. Here, a downlink-centric subframe is a subframe that is used for communications in the downlink direction most of the time; and an uplink-centric subframe is a subframe that is used for communications in the uplink direction most of the time.

[0060] Figure 5is a schematic diagram showing a subframe set 500 (e.g., frame) including one uplink centric subframe 502 every four subframes, with the remaining three of the four subframes being downlink centric subframes 504. Of course, this particular allocation of uplink to downlink centric subframes is merely an example, and any ratio of uplink centric subframes to downlink centric subframes may be utilized in a particular implementation.

[0061] In the illustrated example, the portions of each subframe used for uplink communications are referred to as uplink portions 506, and the portions of each subframe used for downlink communications are referred to as downlink portions 508. Here, gaps, guard periods, guard intervals, or guard regions (not shown) may be utilized after the downlink portion and before the uplink portion (or vice versa). Such gaps may facilitate switching or reconfiguration of RF components, including retuning of phase-locked loops and other radio functions.

[0062] The illustrated downlink-centric subframe 504 includes a control region 510, which may include a physical downlink control channel (PDCCH), and a data region 512, which may include a physical downlink shared channel (PDSCH). The control region 510 may include, among other things, scheduling information for informing a scheduled device (e.g., a subordinate entity) which resources in the data region 512 include information about the particular device.

[0063] The illustrated uplink-centric subframe 502 also includes a control region 514 (which may include a PDCCH) and a data region 516 (which may include a physical uplink shared channel (PUSCH) and / or other suitable channels corresponding to uplink data bursts). The control region 514 may include, among other things, scheduling information for notifying scheduled devices (e.g., lower level entities) which resources in the data region 516 they may use for uplink transmissions.

[0064] As illustrated in this example, both the uplink centric subframe 502 and the downlink centric subframe 504 include a common uplink burst portion 518. In this example, the common UL burst is shown at the end of each subframe, but it is not necessarily limited to the end, and in other examples the common UL burst 518 may appear at any suitable time within the uplink centric subframe 502 or the downlink centric subframe 504, including at the beginning of the subframe or anywhere within the subframe. In some examples, the common UL burst 518 may be constructed in both the uplink centric subframe and the downlink centric subframe in the same manner.

[0065] In one aspect of the present disclosure, the common UL burst 518 may be a relatively short portion of a corresponding subframe, including, for example, two or more symbols. For example, a 2-symbol common UL burst may have a duration of about 31 microseconds (μs). Of course, different durations and different numbers of symbols may be included in a common UL burst within the scope of the present disclosure. That is, any suitable number of symbols (e.g., OFDM symbols) may be utilized in a common UL burst within the scope of the present disclosure. However, for clarity, within the present disclosure, the following references to Figure 6 and 7 A common UL burst including two symbols is described in further detail.

[0066] Here, the common UL burst 518 can be utilized to decouple the waiting time associated with the control channel carried in the common UL burst according to the uplink / downlink mode selected in any given implementation. That is, in the TDD scheme, because more conventional network traffic can usually be in the downlink direction, the downlink center subframe can usually appear much more frequently than the uplink center subframe. In addition, in the typical deployment of macro cells (e.g., the evolved B node in the LTE deployment), the ratio between uplink traffic and downlink traffic remains relatively stable over time. That is, when a large number of users are gathered, even if the UL / DL ratio of any single user may change quite dramatically, the total ratio generally remains nearly the same. However, a small cell (which is different from a macro cell) may only serve a very small number of users, so the total ratio between the UL center subframe and the DL center subframe will change greatly over time.

[0067] Thus, depending on the cell size and the load of the cell, the downlink and uplink patterns may change, and the ratio between uplink centric subframes and downlink centric subframes may be any suitable ratio, from 1 to 1 or otherwise.

[0068] If uplink centric subframes are extremely rare and downlink centric subframes dominate, then there may be a problem in that devices with critical or time-sensitive uplink information to transmit may need to wait for an extended period of time before their uplink information can be transmitted in an uplink centric subframe. In particular, control information, such as channel quality information and feedback (e.g., packet acknowledgment), may have time-sensitive characteristics, and thus their rapid and timely transmission may be important. Therefore, for time-sensitive packets, including a common UL burst region in every subframe or a large portion (e.g., more than 50%) of the subframes (including downlink centric subframes) can help reduce or avoid such extended waiting times.

[0069] In a further aspect of the present disclosure, such a shared UL burst scheme provides the same channel structure to be utilized in both unlicensed and licensed bands. In an unlicensed band, users (e.g., subordinate entities) typically compete for resources and are only able to retain use of a channel for a limited time before relinquishing the channel to other users. Here, if a transmission is received just at the end of the time that a user has the channel and the device loses the channel before having the opportunity to transmit an acknowledgment (or other time-critical uplink packet), the device may be required to wait for an extended period of time for such transmission until the channel can be recaptured. However, with a shared UL burst channel structure, resources for such transmissions may become available in each subframe, thereby reducing or avoiding such delays for time-critical transmissions.

[0070] The common UL burst may additionally or alternatively be used to transmit other control information, such as a scheduling request (SR). A scheduling request may be an uplink information transmission requesting a scheduling entity (e.g., a base station or eNB) to schedule and / or allocate uplink channel resources for use by scheduled devices to transmit uplink data. These resources may appear within the conventional UL burst region 506 illustrated in the uplink centric subframe 502.

[0071] In yet another example, a conventional UL burst may additionally or alternatively be used to carry a sounding reference signal (SRS). In a non-paired TDD spectrum, the channel seen by the scheduled device (e.g., UE or subordinate entity) for downlink transmission is the same channel seen by the scheduling entity (e.g., eNB) for uplink transmission. Therefore, the channel characterization is simplified to a certain extent relative to the channel characterization of the FDD channel. That is, the scheduling entity generally requires information related to the downlink channel as seen by the receiver or subordinate entity in order to schedule resources most appropriately for the user. Although in an FDD channel, the UE measures the channel and sends feedback to the base station to report its channel status; in a TDD channel, the UE may transmit an SRS in an uplink transmission, and the base station may use the transmission to characterize the channel for scheduling downlink transmissions. The SRS transmission is generally expected to be transmitted with low latency, that is, its transmission is time-critical to a certain extent. Thus, placing the SRS in the common UL burst area 518 can decouple its latency from the downlink to uplink mode (or vice versa) in a given implementation.

[0072] Of course, the above are merely examples, and within the scope of the present disclosure, the common UL burst may be used not only for such control information, but may also or alternatively be used to carry uplink payload data with low latency requirements. Here, such uplink payload transmissions in the common UL burst region may be limited to transmitting devices with sufficient power headroom for these transmissions.

[0073] Coupled mode vs. decoupled mode

[0074] Refer again Figure 1 , UE 126 is illustrated as being relatively far from base station 112 (e.g., at or near the cell edge), while another UE 128 is illustrated as being relatively close to base station 112 (e.g., at or near the cell center). As further described below, according to various aspects of the present disclosure, a user similar to UE 128 located at the cell center may have sufficient power headroom to include data transmissions in a common UL burst, while a user similar to UE 126 located at the cell edge may lack power headroom to include data transmissions in a common UL burst. Accordingly, in various aspects of the present disclosure, a user at the cell edge may be configured to perform its common UL burst transmissions in a coupled mode that facilitates coverage extension of control information transmissions, while a user at or near the cell center may be configured to perform its common UL burst transmissions in a decoupled mode that facilitates user data transmissions in addition to control information transmissions.

[0075] That is, these common UL burst regions within the subframes described above may be configured to support all users and devices, including users near the center of the cell and users near the edge of the cell. For users at or near the edge of the cell (whose signals may be weaker because they are relatively far from the base station or scheduling entity), the information content within the common UL burst region may be limited to certain control information that may be carried on the physical uplink control channel (PUCCH), such as packet acknowledgment (ACK) and scheduling request (SR). For these users near or at the edge of the cell, transmission may be performed in a certain mode (referred to as a coupled mode in this disclosure).

[0076] In coupled mode, SRS can be reused or diverted for the purpose of serving demodulation reference signal (DM-RS), so that demodulation of information bits in a common UL burst can be accomplished with coupled SRS / DM-RS signals. That is, in coupled mode transmission, DM-RS (hereinafter referred to as Figure 6 and 7 ) may be omitted. In this way, for coupled mode transmission, additional power that may be consumed by DM-RS pilot transmission may be saved. Thus, coupled mode transmission may have reduced power consumption.

[0077] On the other hand, in the decoupled mode, it can target users or devices that are relatively close to the scheduling entity or base station because their signals can be more easily received by the base station and these devices generally have sufficient power headroom to accommodate the additional pilot transmissions associated with the DM-RS.

[0078] Therefore, if the user or device is relatively close to the cell center or close to the base station or scheduling entity, it is possible to accumulate or supply enough energy to include uplink payload data in the area even during the shorter common UL burst. Accordingly, in one aspect of the present disclosure, for example, a decoupled mode is provided for these users or devices that are relatively close to the cell center or close to the base station or scheduling entity.

[0079] In decoupled mode, a UE or subordinate entity may be enabled to opportunistically transmit uplink payload data with low latency requirements. That is, with decoupled mode, a device operating in decoupled mode may be enabled to transmit information on the PUSCH within a common UL burst region of an uplink centric subframe and a downlink centric subframe. The present disclosure specifically references the PUSCH, however it will be understood that the term is included merely for clarity and that aspects of the present disclosure may utilize any suitable physical uplink channel to carry traffic payload data.

[0080] In the present disclosure, the name "decoupled" with respect to the decoupled mode generally refers to the decoupling of the SRS from the demodulation reference signal (DM-RS). In order to demodulate the PUCCH or PUSCH, a pilot or reference signal may be required. Here, the DM-RS provides a pilot that can be used to demodulate the PUCCH / PUSCH bits. In the decoupled mode, the SRS and DM-RS are different symbols and may have different transmission characteristics. Thus, the SRS and DM-RS are decoupled from each other and may be beamformed or precoded differently.

[0081] In some examples, because decoupled mode users may generally be those users that are close to a scheduling entity or base station, those users may utilize multiple-input multiple-output (MIMO) or other beamforming techniques in their uplink transmissions.

[0082] That is, the lower-level entity 204 (e.g., UE 128, wireless communication device 300, user equipment or UE, etc.) may have multiple antennas that support multiple-input multiple-output (MIMO) technology. The use of MIMO technology enables these wireless communication devices to utilize the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing can be used to transmit different data streams simultaneously on the same frequency. These data streams can be transmitted to a single receiving device to increase the data rate or to multiple receiving devices to increase the total system capacity. This is achieved by spatially precoding each data stream (i.e., applying amplitude and phase scaling) and then transmitting each spatially precoded stream through multiple transmit antennas. The spatially precoded data stream arrives at the receiving device(s) with different spatial signatures, and these different spatial signatures enable each receiving device to recover one or more data streams intended for the device.

[0083] Spatial multiplexing is generally used when channel conditions are good. When channel conditions are less favorable, beamforming can be used to focus the transmit energy in one or more directions. This can be achieved by spatially precoding the data for transmission over multiple antennas.

[0084] With specific reference to the common UL burst, in order to use MIMO, a certain precoding matrix is ​​used to appropriately configure the transmitted information. That is, in one aspect of the present disclosure, in order to enable MIMO or beamforming for uplink data within a common UL burst, the uplink data transmitted within the common UL burst may be precoded using a selected precoding matrix. In general, the selected precoding matrix maps data to antennas for spatial multiplexing and / or beamforming.

[0085] However, in a further aspect of the present disclosure, SRS transmissions within a common UL burst may not be beamformed or precoded for MIMO transmissions. For users who wish to use MIMO in their uplink transmissions, the pilot (i.e., SRS) generally cannot be used as a demodulation reference signal (DM-RS) for demodulating data, since data and pilot use different precoding and are correspondingly beamformed differently. Thus, the SRS and its precoding or beamforming are decoupled from the DM-RS and its precoding or beamforming.

[0086] Figure 6 and 7 is a schematic diagram showing additional details of a common UL burst 518 when it can be configured for transmission in a decoupled mode according to some aspects of the present disclosure. Although these diagrams provide exemplary bandwidth figures, it will be understood that the specific bandwidth values ​​of the control region (illustrated as 10MHz) and the specific bandwidth values ​​of the data region (illustrated as 70MHz) are merely illustrative in nature, and any suitable bandwidth of either region can be utilized in a specific implementation within the scope of the present disclosure. In addition, the location of the control region and the data region may vary depending on the illustrated example. That is, although these diagrams show that the control region is at the top or upper portion of the resource block and the data region is at the bottom or lower portion of the resource block, these can be rearranged within the scope of the present disclosure. In addition, although these diagrams show that the control region and the data region are each completely contiguous, this is not necessary, and within the scope of the present disclosure, one or both of the control and / or data regions may be non-contiguous, thereby occupying two or more separate portions of the resource block.

[0087] Figure 6 and 7 Two different optional formats of the common UL burst 518 in decoupled mode are shown. In the first format, Figure 6In the common UL burst, only control information 602 (eg, ACK / SR) is carried. In the second format, Figure 7 In the common UL burst 518, both control information 702 (e.g., ACK / SR) and data information 704 (e.g., PUSCH) are carried in the common UL burst. In various aspects of the present disclosure, the decoupled mode transmission may include control information in the control region and any suitable amount of data in the data region. That is, in some aspects of the present disclosure, in the common UL burst 518 configured for decoupled mode, the control region may have a fixed bandwidth and the data region may have a variable bandwidth. For example, as in Figure 6 In the first example, the decoupled mode transmission may not include data information in the data region (ie, there is no data region). In another example, as in Figure 7 In the second example of , the decoupled mode transmission may include sufficient data information in the data region to completely fill all subcarriers in the data region. In other examples, any amount of data information between these examples may be transmitted in a particular common UL burst. As described in further detail below, the exact bandwidth of the data region and its allocation among different users performing common UL burst transmissions in decoupled mode may be controlled by a scheduling entity (e.g., an eNB) and communicated to a user or a subordinate entity (e.g., a UE) using a scheduling grant.

[0088] In some examples, a typical symbol may have a duration of about 30 μs or any suitable duration. However, in one aspect of the disclosure, within a common UL burst, some symbols may be shortened relative to other symbols. As an example, in Figure 6 and 7 In the illustration of , the two shorter symbols (the first symbol and the second symbol) may be scaled to completely occupy only the 30 μs common UL burst region 518. However, as mentioned above, a common UL burst may include any suitable number of symbol periods and may utilize any suitable symbol scaling relative to the nominal symbol timing.

[0089] In the example described, Figure 6 and 7 , the first symbol within the common UL burst may include a sounding reference signal (SRS) 604 and 706, and the second symbol within the common UL burst may include control information (e.g., ACK / SR 602, 702) and / or data information (e.g., PUSCH 704). The SRS is essentially a pilot transmitted by a scheduled device (e.g., UE) to enable a base station or scheduling entity to sense (or sound) the channel for the purpose of configuring and scheduling downlink transmissions.

[0090] Here, the SRS is explained as a broadband signal, thereby occupying the entire frequency band (or all subcarriers). However, this is only an example, and it can be assumed that the transmitting party subordinate entity (e.g., UE) can support such transmission across the entire frequency band or all subcarriers. For UEs at or near the center of a cellular cell, support for such broadband transmissions may be relaxed to a certain extent. Transmitting the SRS in this broadband format enables the receiving party device (e.g., a scheduling entity or eNB) to sound the channel within one time slot, thereby saving time relative to transmitting multiple SRSs in different parts of the frequency band or subcarriers. In a further aspect of the present disclosure, the SRS can be mixed or encoded with a scrambling code that varies from UE to UE. In this way, the receiving party scheduling entity (e.g., eNB) can be enabled to separate SRS transmissions from different users or devices using conventional CDMA techniques known to those of ordinary skill in the art.

[0091] The control and data information in the second symbol may include PUCCH for carrying time-sensitive or latency-sensitive control information (such as packet acknowledgement (ACK), scheduling request (SR), etc.), and may include PUSCH for carrying uplink data in some examples. In the illustrated example, PUCCH and PUSCH are separated from each other by frequency. That is, these respective channels may be frequency division multiplexed within a single (one or more) symbol duration within a common UL burst. In this way, the transmission of PUCCH / PUSCH from a high-power user may have less impact on the scheduling entity receiving PUSCH transmissions of other users on different subcarriers.

[0092] like Figure 6 and 7 As illustrated in FIG. 1 , DM-RS pilots 606, 708 are shown as taking every other subcarrier across the frequency band. However, aspects of the present disclosure may utilize other configurations of DM-RS, and DM-RS does not necessarily have to occupy half of the frequency tones or subcarriers across the frequency band, and may occupy 25% or any suitable proportion of the entire frequency band.

[0093] In one aspect of the present disclosure, the PUCCH and PUSCH may each have a separate demodulation reference signal (DM-RS). That is, one pilot or DM-RS may be transmitted in the PUCCH along with the control information bits, and a second pilot or DM-RS may be transmitted in the PUSCH along with the data information bits. The diagram shows that one set of DM-RS pilots is transmitted in every other subcarrier in the PUCCH (control) region, and another set of DM-RS pilots is transmitted in every other subcarrier in the PUSCH (data) region. However, as indicated above, in a specific implementation, the arrangement of other DM-RSs in each region may differ from this example.

[0094] In a further aspect of the present disclosure, for a transmitting device including multiple antennas (such as those configured for beamforming and / or MIMO), each transmit antenna may transmit its own DM-RS that is different from the DM-RS transmitted by other antennas. That is, in order to maximize such uplink MIMO transmission, the receiving device may need to distinguish different pilots (DM-RS signals) from different transmit antennas. According to one aspect of the present disclosure, code division multiplexing (CDM) may be used by a transmitting device (e.g., a UE or a subordinate entity) to achieve this distinction between pilots transmitted by different antennas. That is, these pilots transmitted from two different antennas may be scrambled by two different scrambling codes and then transmitted simultaneously within the same subcarrier. However, the receiving scheduling entity (e.g., an eNB) is enabled to utilize conventional code division multiplexing procedures known to those of ordinary skill in the art to distinguish different pilots from these different transmit antennas.

[0095] Within any given symbol, only a limited amount of resources are available to carry information. By taking some tones or subcarriers out of these available resources to dedicate these tones or subcarriers to pilot transmissions (e.g., SRS and DM-RS), even fewer resources are available to dedicate to data information. For this reason, for uplink MIMO transmissions, it is not desirable to further divide these resources to provide different pilot transmissions for each of the multiple antennas. Thus, when pilot tones (such as DM-RS) are utilized, they can occupy the same time-frequency resources but can be distinguished by different scrambling codes, as described above.

[0096] If a scheduling entity (e.g., an eNB) schedules two users (e.g., UEs) to send data information on the PUSCH, then the users may be scheduled such that each of the users utilizes designated resources identified by the scheduling entity. The scheduling information may be communicated to the users or subordinate entities using a scheduling grant, which may be a unicast or broadcast message, or any other suitable control channel transmission format configured to communicate a scheduling grant. The scheduling grant may be carried on a PDCCH (e.g., Figure 5 in PDCCH 510 and 514).

[0097] In addition, refer to Figure 8 , when a subordinate entity (eg, a UE) has UL data to transmit and wishes to request resources on the PUSCH in a common UL burst, the subordinate entity may request a resource on the PUSCH in the PUCCH region of the common UL burst (see Figure 6 and 7) within a common UL burst. That is, in one subframe, within a common UL burst, the subordinate entity may transmit the scheduling request 802 in the control region, for example, using the PUCCH. In response, the scheduling entity (e.g., the eNB) may determine an appropriate resource allocation 804 for the requesting subordinate entity based on various factors or parameters. For example, the scheduling entity may consider: network load or how the common UL burst is occupied by transmissions of other users; the nature or amount of data that the subordinate entity is requesting to be transmitted; and the characteristics of the SRS received from the requesting scheduling entity. The scheduling entity may transmit a scheduling grant 806 to the subordinate entity using any suitable transmission channel and format to identify the scheduled or allocated resources within the common UL burst of one or more subframes. Accordingly, the subordinate entity may utilize the scheduled resources to transmit 808 its UL data in the data region (e.g., the PUSCH of the common UL burst). In this way, interference or conflicts (which may be relatively high-power transmissions) between subordinate entities configured to transmit using the decoupled mode may be reduced or eliminated.

[0098] On the other hand, unlike data transmissions on the PUSCH within the shared UL burst 518, SRS and control transmissions (e.g., ACK / SR) from different users on the PUCCH within the shared UL burst can share the same time-frequency resources and do not necessarily have to be scheduled. This is because these control transmissions and SRS can be power controlled by the scheduling entity. That is, with appropriate power control and, in some examples, interference cancellation techniques, SRS and control transmissions from different users can simply be superimposed on each other, and the scheduling entity can still be able to receive and decode their respective transmissions. In some examples, these shared SRS / PUCCH transmissions can be distinguished between different users by configuring each user or subordinate entity to apply a different scrambling sequence or code to its transmission, thereby sharing resources using code division multiple access (CDMA). Accordingly, the receiving scheduling entity may be able to distinguish these users' transmissions using conventional CDMA techniques known to those of ordinary skill in the art.

[0099] Waveforms for decoupled mode

[0100] For SRS, in one aspect of the present disclosure, a single carrier waveform may be utilized. For example, a single carrier FDMA (SC-FDMA) waveform as utilized in conventional LTE transmissions, or any other suitable single carrier waveform may be utilized. That is, within a common UL burst 518, SRS may be transmitted by both users close to the scheduling entity and users far from the scheduling entity. In one example, the SRS transmitted by these different user groups need not be of different waveforms. Accordingly, a waveform may be selected that provides sufficient functionality for users near the center of the cell while accommodating any bottlenecks that may be caused by users at the edge of the cell. For users at the edge of the cell, the signal power may be relatively weak due to a large path loss. In order to improve the efficiency of the power amplifiers of these users (including those operating in a decoupled mode near the center of the cell), a single carrier waveform may be used for SRS. That is, using such a single carrier waveform for SRS transmission can save power, which may be particularly useful for users at or near the edge of the cell.

[0101] For SRS in a common UL burst, a single carrier waveform may be configured according to a Zadoff-Chu sequence, as utilized in current LTE standards and as known to those of ordinary skill in the art. In other examples, any other suitable pseudo-random sequence may be used for a single carrier waveform in a common UL burst.

[0102] In further aspects of the present disclosure, the control region of the common UL burst 518 (which may include the PUCCH) may utilize an OFDM waveform that is expanded by a discrete Fourier transform (DFT). In addition, the data region of the common UL burst (which may include the PUSCH) may utilize an OFDM waveform. That is, the PUCCH and the PUSCH may utilize an OFDM waveform that may include a cyclic prefix (CP) to make it relatively easy to multiplex different channels. That is, it may be difficult to multiplex different channels that utilize FDM within the same symbol using a single carrier waveform. Accordingly, because the common UL burst includes symbols in which the PUCCH and the PUSCH are multiplexed together with the DM-RS pilot, aspects of the present disclosure may use an OFDM waveform for the symbol(s).

[0103] The SRS region and control region (PUCCH) within a common UL burst may be shared by multiple users (e.g., lower level entities), wherein multiple access to these resources is achieved using CDMA, as described above. That is, within the SRS region and control region of a common UL burst, the users may be distinguished by their respective use of different sequences in the code domain, wherein these sequences are assigned to the respective users, for example, by a network or scheduling entity. In addition, as described above, different users may be appropriately power controlled by the network or scheduling entity to further enable reception of each user's SRS / PUCCH transmission.

[0104] In yet further aspects of the present disclosure, a data region (e.g., PUSCH) within a common UL burst may be shared by multiple users (e.g., subordinate entities), wherein multiple access to these resources is achieved using OFDMA. That is, within the data region of a common UL burst, users may be distinguished by their respective use of different frequency subcarriers, wherein the selection of the subcarrier(s) for their data transmission is made based on a scheduling grant transmitted from a scheduling entity to those respective users. In some examples, use of the PUSCH in a common UL burst for uplink data transmission may be limited to users with sufficient power headroom (e.g., available power headroom greater than a threshold). In addition, use of the PUSCH in a common UL burst for uplink data transmission may be limited to users with uplink payload data that require lower latency (e.g., latency lower than would otherwise be obtained from using, for example, the data region of a conventional UL burst in a UL-centered subframe).

[0105] Fig. 9 is a diagram illustrating a method of operating a subordinate entity to perform wireless communications on a time division duplex (TDD) carrier according to an aspect of the present disclosure. In some examples, the method may use Figure 1 -It is performed by any of the subordinate entities illustrated in -4 and 8, or any wireless communication device.

[0106] according to Fig. 9 The lower level entity may utilize the common UL burst block 320 (see Figure 3 ) to transmit a common uplink burst in a downlink centric subframe 902 and an uplink centric subframe 904 on a TDD carrier. For example, a subordinate entity may utilize a DL centric subframe block 322 to prepare and transmit a common uplink burst 518 in a DL centric subframe 504 (see Figure 5 For example, the subordinate entity may utilize the UL centric subframe block 324 to prepare and transmit a common uplink burst in the UL centric subframe 502 (see Figure 5 ). The common uplink burst may be the same as the common UL burst 518 described with respect to 5-7. For example, an uplink burst (eg, Figure 5 In other examples, common uplink bursts may be transmitted in any desired number (eg, more than 50% of the total number of subframes) of subframes including DL-centric subframes and UL-centric subframes to provide more UL transmission opportunities.

[0107] The uplink burst includes: a first symbol including a sounding reference signal (SRS) configured to enable sounding of a TDD carrier; and a second symbol including information bits and a signal similar to Figure 6 and 7 The SRS and DM-RS may be precoded differently. For example, in Fig.10 , a lower-level entity may utilize a precoder 1000 to apply a first precoding matrix 1002 to an SRS, and apply a second precoding matrix 1004, which is different from the first precoding matrix 1002, to a DM-RS. Separate precoding of the SRS and the DM-RS allows control information and / or data information to be transmitted using multiple-input multiple-output (MIMO).

[0108] It should be understood that the specific order or hierarchy of steps in the disclosed methods is an illustration of an exemplary process. Based on design preferences, it should be understood that the specific order or hierarchy of steps in these methods can be rearranged. The attached method claims present elements of the various steps in a sample order and are not meant to be limited to the specific order or hierarchy presented unless specifically stated herein.

[0109] As will be readily appreciated by those skilled in the art, the various aspects described throughout this disclosure can be extended to any suitable telecommunication system, network architecture, and communication standard. As an example, various aspects can be applied to UMTS systems, such as W-CDMA, TD-SCDMA, and TD-CDMA. Various aspects can also be applied to systems using Long Term Evolution (LTE) (in FDD, TDD, or both modes), Advanced LTE (LTE-A) (in FDD, TDD, or both modes), LTE-U,, CDMA2000, Evolution Data Optimization (EV-DO), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE 802.20, Ultra Wideband (UWB), Bluetooth, and / or other suitable systems, including those described by wide area network standards to be defined. The actual telecommunication standard, network architecture, and / or communication standard adopted will depend on the specific application and the overall design constraints imposed on the system.

[0110] Within the present disclosure, the wording "exemplary" is used to mean "serving as an example, instance, or illustration". Any implementation or aspect described herein as "exemplary" is not necessarily to be construed as superior or superior to other aspects of the present disclosure. Likewise, the term "aspect" does not require that all aspects of the present disclosure include the discussed features, advantages, or modes 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, objects A and C may still be considered to be coupled to each other - even if they are not in direct physical contact with each other. For example, a first object may be coupled to a second object even if the first object is never in direct physical contact with the second object. The terms "circuit" and "circuitry" are used broadly and are intended to include both hardware implementations of electronic devices and conductors, which when connected and configured enable the functions described in the present disclosure to be performed without limitation on the type of electronic circuits, and software implementations of information and instructions, which when executed by a processor enable the functions described in the present disclosure to be performed.

Claims

1. A method operable at a subordinate entity for wireless communication over a time division duplex (TDD) carrier, the method comprising: transmitting an uplink burst within a downlink centric subframe on the TDD carrier, wherein the downlink centric subframe comprises a control region and a data region for downlink data, and wherein the uplink burst comprises: a first symbol including a sounding reference signal (SRS) configured to enable sounding of the TDD carrier; and A second symbol includes information bits and a demodulation reference signal (DM-RS), wherein the DM-RS is configured to enable demodulation of the information bits carried within the second symbol.

2. The method of claim 1, wherein: The second symbol includes control information including channel quality information, packet acknowledgement, scheduling request, or a combination thereof.

3. The method of claim 1, wherein: The SRS in the first symbol of the uplink burst spans all subcarriers within a resource block on the TDD carrier.

4. The method of claim 1, further comprising: Applying a first precoding matrix to the SRS; as well as A second precoding matrix different from the first precoding matrix is ​​applied to the DM-RS.

5. The method of claim 1, further comprising: A scrambling code is applied to the SRS, the scrambling code being configured to enable code division multiple access (CDMA) among a plurality of subordinate entities.

6. The method of claim 1, wherein: Transmitting the uplink burst within the downlink centric subframe includes transmitting the uplink burst in last two symbol periods of the downlink centric subframe.

7. A subordinate entity configured for wireless communication on a time division duplex (TDD) carrier, the subordinate entity comprising: Transceiver; Memory; as well as a processor communicatively coupled to the transceiver and the memory, the processor configured to: transmitting an uplink burst within a downlink centric subframe on the TDD carrier, wherein the downlink centric subframe comprises a control region and a data region for downlink data, and wherein the uplink burst comprises: a first symbol comprising a sounding reference signal (SRS) configured to enable sounding of the TDD carrier; as well as The second symbol includes information bits and a demodulation reference signal (DM-RS), wherein The DM-RS is configured to enable demodulation of the information bits carried within the second symbol.

8. The subordinate entity according to claim 7, wherein: The second symbol includes control information including channel quality information, packet acknowledgement, scheduling request, or a combination thereof.

9. The subordinate entity according to claim 7, wherein: The SRS in the first symbol of the uplink burst spans all subcarriers within a resource block on the TDD carrier.

10. The subordinate entity according to claim 7, characterized in that: The processor is further configured to: applying a first precoding matrix to the SRS; and A second precoding matrix different from the first precoding matrix is ​​applied to the DM-RS.

11. The subordinate entity according to claim 7, characterized in that: The processor is further configured to: A scrambling code is applied to the SRS, the scrambling code being configured to enable code division multiple access (CDMA) among a plurality of subordinate entities.

12. The subordinate entity of claim 7, wherein the processor is further configured to: The uplink burst is transmitted in last two symbol periods of the downlink central subframe.

13. A subordinate entity configured for wireless communication over a time division duplex (TDD) carrier, comprising: means for receiving a downlink transmission; as well as Means for transmitting an uplink burst in a downlink centric subframe on the TDD carrier, wherein the downlink centric subframe comprises a control region and a data region for downlink data, and wherein the uplink burst comprises: a first symbol comprising a sounding reference signal (SRS) configured to enable sounding of the TDD carrier; as well as A second symbol includes information bits and a demodulation reference signal (DM-RS), wherein the DM-RS is configured to enable demodulation of the information bits carried within the second symbol.

14. The subordinate entity according to claim 13, wherein: The second symbol includes control information including channel quality information, packet acknowledgement, scheduling request, or a combination thereof.

15. The subordinate entity of claim 13, wherein: The SRS in the first symbol of the uplink burst spans all subcarriers within a resource block on the TDD carrier.

16. The subordinate entity of claim 13, further comprising: means for applying a first precoding matrix to the SRS; as well as means for applying a second precoding matrix different from the first precoding matrix to the DM-RS.

17. The subordinate entity of claim 13, further comprising: means for applying a scrambling code to the SRS, the scrambling code being configured to enable code division multiple access (CDMA) among a plurality of subordinate entities.

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