Non-random cyclic shift selection for avoiding cyclic shift conflicts in sidelink control channels

Abstract

A user equipment (UE) transmits a first transmission including first sidelink control information (SCI) using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI for a second transmission from the UE. The UE then transmits a second transmission including the second SCI using a second cyclic shift. A receiving UE receives the first transmission including the first SCI with the first cyclic shift from a second UE and uses the information in the first SCI to determine cyclic shift information about the second cyclic shift of the second SCI for the second transmission from the UE using the information in the first SCI. The receiving UE may exclude the second cyclic shift from selection using the information received in the first SCI.

Description

[0001] This application claims priority to and the benefit of U.S. non-provisional patent application Ser. No. 16 / 827,513, filed on Mar. 23, 2020, and entitled “Non-random cyclic shift selection to avoid cyclic shift collision for sidelink control channel,” which is hereby incorporated by reference in its entirety. background Technical Field

[0003] The present disclosure relates generally to communication systems, and more particularly to vehicle-to-vehicle (V2V), vehicle-to-everything (V2X), or other device-to-device (D2D) communications.

[0004] introduction

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single-carrier frequency division multiple access (SC-FDMA), and time division synchronous code division multiple access (TD-SCDMA).

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)) and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Various aspects of wireless communication may include direct communication between devices, such as in V2X and / or other D2D communications. There is a need to further improve V2X and / or other D2D technologies. These improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies.

[0007] Overview

[0008] The following is a brief summary of one or more aspects to provide a basic understanding of such aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0009] In one aspect of the present disclosure, a method, computer-readable medium, and apparatus for wireless communication at a user equipment (UE) are provided. The apparatus transmits a first transmission including first sidelink control information (SCI) using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI used for a second transmission from the UE. The apparatus transmits a second transmission including the second SCI using the second cyclic shift.

[0010] In one aspect of the present disclosure, a method, computer-readable medium, and apparatus for wireless communication at a first UE are provided. The apparatus receives a first transmission from a second UE including a first SCI having a first cyclic shift, and uses information in the first SCI to determine cyclic shift information about a second cyclic shift of a second SCI for a second transmission from the UE. The apparatus may use the information received in the first SCI to exclude the second cyclic shift from selection of its own cyclic shift.

[0011] To accomplish the foregoing and related ends, one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and accompanying drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are indicative of but a few of the various ways in which the principles of the various aspects may be employed, and this description is intended to encompass all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0014] Figure 2 Illustrated are example aspects of a sidelink slot structure.

[0015] Figure 3 is a diagram illustrating an example of a first device and a second device involved in wireless communication based on, for example, V2X and / or other D2D communications.

[0016] Figure 4 A communication system including V2X or other D2D communications is explained.

[0017] Figure 5An example of a first transmission providing resource information about a second transmission is illustrated.

[0018] Figure 6 An example of a collision between transmissions from two devices is illustrated.

[0019] Figure 7 An example communication flow between devices communicating based on V2X or other D2D communications is illustrated.

[0020] Figure 8 is a flow chart of a method of wireless communication at a transmitting device.

[0021] Figure 9 is a flow chart of a method of wireless communication at a transmitting device.

[0022] Figure 10 is a conceptual data flow diagram illustrating the flow of data between different devices / components in an example apparatus.

[0023] Figure 11 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.

[0024] Detailed description

[0025] 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 to avoid overstating such concepts.

[0026] Several aspects of telecommunications systems will now be presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively, "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0027] As an example, an element, or any part of an element, or any combination of elements can be implemented as a "processing system" comprising one or more processors. Examples of processors include: a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set computing (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gating logic, a discrete hardware circuit, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. One or more processors in a processing system can execute software. Software should be broadly interpreted to mean instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether it is described in software, firmware, middleware, microcode, hardware description language, or other terms.

[0028] Accordingly, in one or more example embodiments, the functions described can be implemented in hardware, software, or any combination thereof. If implemented in software, each function can be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of the above-mentioned types of computer-readable media, or any other medium that can be used to store computer-accessible instructions or data structure forms of computer-executable code.

[0029] Figure 1 1 is a diagram illustrating an example of a wireless communication system and access network 100. Some wireless communication systems (also known as wireless wide area networks (WWANs)) may include base stations 102, UEs 104, an evolved packet core (EPC) 160, and a core network (e.g., 5GC) 190. Base stations 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Macro cells include base stations. Small cells include femto cells, pico cells, and micro cells.

[0030] Base stations 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a backhaul link 132 (e.g., an S1 interface). Base stations 102 configured for NR (collectively referred to as the Next Generation RAN (NG-RAN)) can interface with the core network 190 via a backhaul link 184. Among other functions, the base stations 102 can perform one or more of the following functions: delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of alert messages. Base stations 102 may communicate with each other directly or indirectly (eg, through EPC 160 or core network 190) over backhaul links 134 (eg, an X2 interface). Backhaul links 134 may be wired or wireless.

[0031] Base stations 102 can communicate wirelessly with UEs 104. Each base station 102 can provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102′ can have a coverage area 110′ that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include a home evolved Node B (eNB) (HeNB), which can provide service to a restricted group known as a closed subscriber group (CSG). The communication link 120 between the base station 102 and the UE 104 can include uplink (UL) (also known as reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (DL) (also known as forward link) transmissions from the base station 102 to the UE 104. The communication link 120 can utilize multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. These communication links can be over one or more carriers. Base station 102 / UE 104 may use spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) for each carrier allocated in the carrier aggregation for a total of up to Yx MHz (x component carriers) for transmission in each direction. These carriers may or may not be contiguous to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated to DL compared to UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carriers may be referred to as secondary cells (SCells).

[0032] The wireless communication system may further include a Wi-Fi access point (AP) 150 in communication with a Wi-Fi station (STA) 152 in the 5 GHz unlicensed spectrum via a communication link 154. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) to determine whether the channel is available before communicating.

[0033] Small cell 102′ may operate in licensed and / or unlicensed spectrum. When operating in unlicensed spectrum, small cell 102′ may employ NR and use the same 5 GHz unlicensed spectrum as used by Wi-Fi AP 150. Small cell 102′ employing NR in the unlicensed spectrum may improve access network coverage and / or increase access network capacity.

[0034] Whether a small cell 102′ or a large cell (e.g., a macro base station), base station 102 may include an eNB, a gNode B (gNB), or other types of base stations. Some base stations 180 (such as gNBs) may operate in traditional sub-6 GHz spectrum, millimeter wave (mmW) frequencies, and / or near-mmW frequencies to communicate with UEs 104. When a gNB operates in mmW or near-mmW frequencies, the gNB may be referred to as a mmW base station. Extremely high frequency (EHF) is a portion of the RF spectrum in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near-mmW extends down to 3 GHz frequencies with a wavelength of 100 mm. Super high frequency (SHF) bands extend between 3 GHz and 30 GHz and are also referred to as centimeter waves. Communications using mmW / near-mmW radio frequency bands suffer from extremely high path loss and short range. A mmW base station, such as base station 180 , may utilize beamforming 182 with UE 104 to compensate for the extremely high path loss and short range.

[0035] The electromagnetic spectrum is often subdivided by different authors or entities into different categories, bands, channels, etc. based on frequency / wavelength. For example, in 5G NR, two initial operating bands have been identified as frequency ranges designated FR1 (410 MHz-7125 MHz) and FR2 (24250 MHz–52600 MHz). Although a portion of FR1 is greater than 6 GHz (>6000 MHz), FR1 is often (interchangeably) referred to as the sub-6 GHz band in various documents and articles on the subject of 5G NR. Similar naming issues sometimes arise in various documents and articles on the subject of 5G NR regarding FR2. Although a portion of FR2 is less than 30 GHz (<30000 MHz), FR2 is often (interchangeably) referred to as the millimeter wave band. However, some authors / entities prefer to define wireless signals with wavelengths between 1 and 10 mm as falling within the millimeter wave band (30 GHz–300 GHz).

[0036] With the above examples in mind, unless specifically stated otherwise, it should be understood that, if used as an example herein, the term "sub-6 GHz" may refer to all or a portion of FR1 for 5G NR. Furthermore, unless specifically stated otherwise, it should be understood that, as used as an example herein, the term "millimeter wave" may refer to all or a portion of FR2 for 5G NR and / or all or a portion of the 30 GHz-300 GHz band. It should also be understood that the terms "sub-6 GHz" and "millimeter wave" are intended to represent possible modifications to such example frequency bands that may affect the decisions of authors / entities regarding wireless communications, such as those given by way of example herein.

[0037] It should be understood that the above examples are not necessarily intended to limit the claimed subject matter. For example, unless otherwise stated, the claimed subject matter related to wireless communications is not necessarily intended to be limited to frequency bands defined by any particular author / entity, etc.

[0038] Devices can use beamforming to transmit and receive communications. For example, Figure 1 It is illustrated that the base station 180 may transmit beamformed signals to the UE 104 in one or more transmission directions 182'. The UE 104 may receive beamformed signals from the base station 180 in one or more receive directions 182″. The UE 104 may also transmit beamformed signals to the base station 180 in one or more transmit directions. The base station 180 may receive beamformed signals from the UE 104 in one or more receive directions. The base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of the base station 180 / UE 104. The transmit direction and receive direction of the base station 180 may be the same or different. The transmit direction and receive direction of the UE 104 may be the same or different. Although the beamformed signals are illustrated between the UE 104 and the base station 102 / 180, aspects of beamforming may similarly be applied by the UE 104 or RSU 107 to communicate with another UE 104 or RSU 107, such as based on V2X, V2V, or D2D communication.

[0039] EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. MME 162 may be in communication with a Home Subscriber Server (HSS) 174. MME 162 is a control node that handles signaling between UE 104 and EPC 160. Generally speaking, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are passed through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP Services 176. IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. The BM-SC 170 can provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 can serve as the entry point for content providers' MBMS transmissions, authorize and initiate MBMS bearer services within the Public Land Mobile Network (PLMN), and schedule MBMS transmissions. The MBMS Gateway 168 can be used to distribute MBMS traffic to base stations 102 within the Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a specific service, and can be responsible for session management (start / stop) and collecting eMBMS-related charging information.

[0040] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may be in communication with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Generally speaking, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are passed through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to the IP services 197. The IP services 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), PS streaming services, and / or other IP services.

[0041] A base station may also be referred to as a gNB, a NodeB, an evolved NodeB (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. Base station 102 provides an access point for UE 104 to EPC 160 or core network 190. Examples of UE 104 include a cellular phone, a smartphone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet device, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similarly functional device. Some UEs 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, an oven, a vehicle, a heart monitor, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0042] Some UEs 104 can communicate with each other using device-to-device (D2D) communication links 158. In some examples, the D2D communication links 158 can use DL / UL WWAN spectrum. The D2D communication links 158 can use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication can be achieved through various wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0043] Some wireless communication networks may include D2D communications between vehicle-based communication devices that may communicate according to: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from a vehicle-based communication device to a road infrastructure node, such as a roadside unit (RSU)), vehicle-to-network (V2N) (e.g., from a vehicle-based communication device to one or more network nodes, such as a base station), cellular vehicle-to-everything (C-V2X), and / or combinations thereof and / or communications with other devices, which may be collectively referred to as vehicle-to-everything (V2X) communications. Although Figure 1 It is illustrated that some communication systems may include base stations 102 or 180, but in some examples, V2X communication may be performed without a base station. Figure 1 In certain aspects, a UE 104 (e.g., a transmitting vehicle user equipment (VUE) or other UE) may be configured to transmit messages directly to another UE 104. The communication may be based on V2X or other D2D communications, such as Proximity Services (ProSe). V2X and / or other D2D based communications may also be transmitted and received by other transmitting and receiving devices, such as roadside units (RSUs) 107. Aspects of the communication may be based on PC5 or sidelink communications, for example, as combined with Figure 2 Although the following description may provide examples regarding V2X / D2D communications in conjunction with 5G NR, the concepts described herein may be applicable to other similar areas such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0044] The UE may use a cyclic shift to transmit communications including SCI, such as V2X or other D2D communications. The cyclic shift may be randomly selected from a set of potential cyclic shifts (such as from a set of {0, 3, 6, 9}). Figure 1 In certain aspects, the UE 104 may include a cyclic shift (CS) information component 198 configured to transmit a first SCI including information about a second cyclic shift of a second SCI. The UE 104 may then transmit the second SCI using the second cyclic shift. In some examples, the first SCI may be included in an initial transmission, and the second SCI may be a retransmission. In some examples, the first SCI and the second SCI may be included in a semi-persistent scheduling (SPS) transmission. A receiving UE (e.g., another UE 104) may include a CS determination component 199 configured to receive the first SCI and use information in the first SCI to determine information about the second cyclic shift of the second SCI, e.g., whether the second cyclic shift of the second SCI is the same as the first cyclic shift and / or is a specific value of the second cyclic shift. The UE 104 may then exclude the second cyclic shift from its own cyclic shift selection. Thus, the information carried in the first SCI may help the receiving UE avoid cyclic shift conflicts. Although various aspects have been described in conjunction with UE 104, an RSU or other V2X device can similarly include a CS information component 198 and / or a CS determination component 199. Likewise, UE 104 can include both CS information component 198 and CS determination component 199, with the UE 104 using the CS information component 198 when transmitting communications and the UE using the CS determination component 199 when receiving communications.

[0045] Figure 2 An example diagram 200 illustrating sidelink subframes within a frame structure that may be used for sidelink communications (eg, between UEs 104, between a UE and infrastructure, between a UE and an RSU, etc.) is illustrated. Figure 1 This is just one example of a potential frame structure, and aspects presented herein may also be applied to other frame structures. In some examples, the frame structure may be based on the LTE frame structure. In some examples, the slot structure may be based on the 5G NR frame structure. For example, the concepts described herein may be applicable to other similar areas such as 5G NR, LTE, LTE-A, CDMA, GSM, and other wireless technologies. Figure 2 The example in FIG200 is merely an example, and other wireless communication technologies may have different frame structures and / or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include two time slots. Each time slot may include 7 SC-FDMA symbols. For time slot configuration 0, each time slot may include 14 symbols, while for time slot configuration 1, each time slot may include 7 symbols. Although diagram 200 illustrates a single RB subframe, sidelink communications may include multiple RBs.

[0046] A resource grid may be used to represent the frame structure. Each time slot may include a resource block (RB) (also called a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a number of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme. Figure 2 As explained in , some REs may include reference signals, such as demodulation RS (DMRS). At least one codeword may be used for feedback, as described herein. Codewords before and / or after the feedback may be used to switch between data reception and feedback transmission. Another codeword (e.g., at the end of a subframe) may be used as a protection codeword that does not need to be transmitted / received. This protection enables the device to switch from operating as a transmitting device to preparing to operate as a receiving device (e.g., in a subsequent subframe). As explained, data or control may be transmitted in the remaining REs. For example, data may be carried in the PSSCH, and control information may be carried in the PSCCH. The control information may include SCI. The location of any of the reference signals, control, and data may be related to Figure 2 The examples explained in are different.

[0047] Figure 33 is a block diagram 300 of a first device 310 configured for wireless communication with a second device 350. Devices 310 and 350 may be configured to transmit and / or receive V2X or other D2D communications. The communications may be based on, for example, a sidelink and may be exchanged using a PC5 interface. Device 310 may include a UE, an RSU, or another wireless device communicating using V2X or D2D. The receiving device may include a UE, an RSU, or another wireless device communicating using V2X or D2D. Packets may be provided to a controller / processor 375 that implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer.

[0048] The transmit (TX) processor 316 and the receive (RX) processor 370 implement Layer 1 functionality associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) coding / decoding of the transport channel, interleaving, rate matching, mapping onto the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation 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)). The decoded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time 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 generate multiple spatial streams. Channel estimates from a channel estimator 374 can be used to determine the coding and modulation schemes and for spatial processing. The channel estimates can be derived from a reference signal and / or channel condition feedback transmitted by the device 350. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX can modulate an RF carrier with a corresponding spatial stream for transmission.

[0049] At device 350, each receiver 354RX receives a signal via its respective antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. TX processor 368 and RX processor 356 implement Layer 1 functionality associated with various signal processing functions. RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for device 350. If multiple spatial streams are destined for device 350, they may be combined into a single OFDM symbol stream by RX processor 356. RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). This 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 transmitted by device 310. These soft decisions may be based on channel estimates calculated by channel estimator 358. These soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by device 310. These data and control signals are then provided to controller / processor 359, which implements layer 3 and layer 2 functionality.

[0050] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. The controller / processor 359 may provide demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0051] Similar to the functionality described in conjunction with transmissions performed by device 310, the controller / processor 359 may provide RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing MAC SDUs onto TBs, demultiplexing MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0052] Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the device 310 may be used by a TX processor 368 to select an appropriate coding and modulation scheme, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0053] The transmission is processed at device 310 in a manner similar to that described in conjunction with the receiver functionality at device 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to an RX processor 370.

[0054] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. The controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing. The controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0055] At least one of the TX processor 368, RX processor 356, or controller / processor 359 of device 350, or the TX 316, RX processor 370, or controller / processor 375 of device 310 may be configured to perform a combined Figure 1 The aspects described in 198 and / or 199.

[0056] V2X or other D2D communications can be based on the combination of Figure 2 Describe the structure of various aspects. Figure 4An example of V2X communication 400 involving multiple UEs is illustrated. For example, a transmitting UE 402 may transmit a transmission 414 (e.g., including a control channel and / or a corresponding data channel), which may be received by UEs 404, 406, and 408. For example, the transmitting UE 402 may transmit a transmission including control information and data. A receiving UE (e.g., UE 404, 406, or 408) may receive the control information but fail to receive the corresponding data, such as due to a failed cyclic redundancy check (CRC). In some examples, a receiving UE (e.g., UE 404, 406, or 408) may receive the data portion without the corresponding control information in the transmission, for example, if the UE uses control information from an initial transmission to receive retransmitted data. The control channel may include information used to decode the data channel and may also be used by a receiving device to avoid interference by refraining from transmitting on occupied resources during the data transmission. The resources to be occupied by the data transmission may be indicated in a control message from the transmitting device. For example, UE 402 may transmit an SCI in the PSCCH that provides information about the presence and location of other transmissions from the UE. The SCI may be transmitted, for example, in the physical resource block of each time slot in each subframe in which the corresponding PSSCH is transmitted. The SCI may carry information about another transmission. For example, the SCI may indicate the time gap between these transmissions (e.g., between the first transmission and the second transmission). The first transmission may be an initial transmission and the retransmission may be a retransmission. The first and second transmissions may be SPS transmissions. For example, the SCI may include a field indicating the time gap between these transmissions. The SCI may also indicate the time and frequency resources used for the second transmission. For example, the SCI may indicate resource reservation. The SCI may include other information used for data transmission, such as MCS information, priority information, etc. A reference signal (such as a DM-RS) may be associated with the PSCCH and, for example, may be transmitted together with the SCI in the PSCCH.

[0057] When transmitting the PSCCH, the UE may apply a cyclic shift to the DM-RS in a subframe. The UE may randomly select a cyclic shift to apply to the DM-RS in each PSCCH transmission. For example, the UE may select the cyclic shift from a set of possible cyclic shifts (e.g., {0, 3, 6, 9}). The UE may randomly select a cyclic shift for the DM-RS. Table 1 illustrates an example reference signal parameter set for the PSCCH, e.g., for a DM-RS transmitted in the PSCCH. The UE may use any of the example reference signal parameters illustrated in Table 1 (e.g., group hopping, sequence hopping, cyclic shift, orthogonal sequence, reference signal length, number of layers, and / or number of antenna ports) to transmit a reference signal, such as a DM-RS associated with an SCI. Different parameters may be used for different transmission modes. As illustrated by the example in Table 1, in some sidelink transmission modes (such as sidelink transmission mode 3 and / or sidelink transmission mode 4), the cyclic shift n is greater than or equal to 0. cs,λ In the example of Table 1, the UE may randomly select the cyclic shift from {0, 3, 6, 9}.

[0058] Table 1

[0059]

[0060] In addition to operating as a receiving device, UE 402, 404, 406, and / or 408 may each be capable of operating as a transmitting device. Thus, UE 406 and 408 are illustrated as transmitting transmissions 416 and 420, respectively. Transmissions 414, 416, and / or 420 may be broadcast or multicast to nearby devices. For example, UE 414 may transmit communications intended for reception by other UEs within range 401 of UE 414. Additionally or alternatively, a UE may transmit unicast communications to a specific UE. RSU 407 may receive communications from and / or transmit communications to UE 402, 404, 406, and / or 408. UE 402, 404, 406, 408, or RSU 407 may include a CS information component 198 and / or a CS determination component 199, as described in conjunction with Figure 1 described.

[0061] Because multiple UEs may broadcast V2X communications using autonomous transmissions, collisions may occur between transmissions from different UEs. A collision refers to the overlap in time and / or frequency between a transmission from a first UE and a transmission from a second UE. To attempt to avoid such collisions, a UE may transmit communications after making a determination regarding available resources. Therefore, channel access may be based on the UE's observation of available resources.

[0062] Figure 5An example diagram 500 illustrating V2X communications is shown. Figure 5 The concept of using subframes is illustrated, but these aspects can be similarly applied to communications based on time slots or other timing information.The first transmission includes SCI 502 and data 504. Figure 5 The example in illustrates SCI 502 and data 504 in adjacent frequency resources. This is merely an example illustrating the concept of a transmission including data and SCI. In other examples, SCI 502 and data 504 may alternatively be transmitted in non-adjacent frequency resources. SCI 502 may be transmitted in PSCCH, and data 504 may be transmitted in PSSCH. As illustrated by arrow 503, SCI 502 includes information about the data transmission 504 that enables the receiving device to receive data 504, such as MCS information, frequency resources and / or time resources used to transmit the data, whether the data is in an initial transmission or a retransmission, and the like. Additionally, as illustrated by arrow 505, SCI 502 includes information about another transmission from the UE (e.g., SCI 506 and / or data 508). SCI 506 and data 508 are illustrated as being transmitted in adjacent frequency resources. In other examples, SCI 506 and data 508 may be transmitted in non-contiguous frequency resources.

[0063] The other transmission (e.g., data 508) may be a retransmission of the first transmission (e.g., data 504). In some examples, the first data transmission may be referred to as RV0, and the second data transmission may be referred to as RV2 and may be based on a HARQ bundling mechanism and control. In some examples, the UE may transmit an initial transmission and two retransmissions. Thus, SCI 502 may indicate the resources used for the two retransmissions.

[0064] In another example, both transmissions may be based on the SPS, and each transmission may indicate a subsequent transmission period (eg, 20 subframes, 50 subframes, 100 subframes, 200 subframes, ..., 1000 subframes, etc.) before the next transmission.

[0065] The SCI 502 may carry information about the time and / or frequency of the resources used for the second transmission. As illustrated, the SCI 502 may carry information about the time gap (e.g., subframe gap) between the two transmissions, information about the frequency resources used for the second transmission (e.g., starting subchannel). Figure 5, a first transmission is transmitted at subframe N, and there is a gap of K subframes before a second transmission occurring at subframe N+K. The first transmission is transmitted using starting subchannel j, and the second transmission is transmitted using starting subchannel i. For example, SCI 502 may indicate a gap of K subframes and may indicate starting subchannel i for the second transmission. As illustrated by arrow 507, SCI 506 includes information about a data transmission 508 that enables a receiving device to receive data 508, such as MCS information, information about frequency resources and / or time resources used to transmit the data, whether the data is an initial transmission or a retransmission, etc. Additionally, as illustrated by arrow 505, SCI 502 may include information about SCI 506 and / or data 508. In some examples, SCI 502 and SCI 506 may carry similar information. As mentioned above, the UE may randomly select a cyclic shift to apply to the DM-RS in each subframe that includes the SCI. Therefore, SCI 502 and SCI 506 will each have a randomly selected cyclic shift applied to the DM-RS in the subframe.

[0066] Figure 6An example of a communication 600 involving a collision between transmissions from two different UEs is illustrated. For example, a first UE may transmit SCI 601 indicating a second transmission using resources 603, as illustrated by arrow 605. A different UE may transmit SCI 602 indicating the same (or at least partially overlapping) time and / or frequency resources 603 for the second transmission, as indicated by arrow 607. The second transmissions from the two UEs may be retransmissions, SPS transmissions, etc. For example, a first UE may transmit a first transmission 610 comprising SCI 601 and data 605 and transmit a second transmission (whether a retransmission of the first transmission 610 or an SPS transmission) using resources 603. A second UE may transmit a first transmission 620 comprising SCI 602 and data 604 and transmit a second transmission (whether a retransmission of the first transmission 620 or an SPS transmission) using resources 603. If the DM-RS associated with the two transmissions have different cyclic shifts, a UE receiving overlapping PSCCH transmissions from the two UEs in resource 603 may be able to distinguish the SCI used for the overlapping PSCCH transmissions. If the DM-RSs of the overlapping transmissions from the two UEs have randomly selected the same cyclic shift, the receiving UE may experience reduced blind decoding performance and / or reduced signal-to-noise ratio (SNR). When one UE transmits in parallel with another UE and uses the same cyclic shift value from a set of four values ​​for the DM-RS associated with the SCI, a collision may occur. For two UEs transmitting in overlapping time and frequency resources, the probability that the two UEs will randomly select the same cyclic shift is 4 / 16. Therefore, for two UEs using overlapping time and frequency resources, there may be a collision rate of approximately 25%. If three UEs transmit using overlapping time and frequency resources, the probability that at least two UEs will randomly select the same cyclic shift from a set or four cyclic shift values ​​is approximately 48 / 64=75%.

[0067] If the receiving UE cannot accurately receive the SCI (for example, the two SCIs overlapping in resource 603), the receiving UE may not accurately receive the corresponding data. In some examples, if the UE cannot receive the corresponding SCI, the UE may not exclude the time and / or frequency resources indicated in the overlapping SCI for future transmission. The overlapping SCI that cannot be received by the receiving UE can be considered as an undetected PSCC. Reducing the detection of overlapping SCI can degrade communication by reducing congestion control between UEs. The receiving UE can use measurements of signals received from other UEs to assist in the performance of link management. If the collision causes the receiving device to be unable to receive the PSCCH used by the UE for link management, the receiving UE may miss synchronization information, timing offset information, etc., which may cause link degradation. The collision may result in reduced PSSCH performance because the receiving UE cannot receive the SCI carrying information for the PSSCH. Therefore, the UE can discard the PSSCH based on failure to detect or failure to correctly receive the corresponding control information. In some examples, PSSCH may have better decoding performance than PSCCH, eg, based on MCS 0, 96 PRBs, etc. HARQ, for example, combined with repetition of transmissions, may provide assistance, eg, even in poor conditions with low SNR.

[0068] Various aspects presented herein improve congestion control, link management, and PSSCH performance by providing a way for UEs to avoid selecting the same cyclic shift value for overlapping transmissions. As presented herein, a UE can provide information in one transmission that assists a receiving UE in determining the cyclic shift value to apply to another transmission. By knowing the cyclic shift value, another UE can exclude the indicated cyclic shift value from its own cyclic shift selection. For example, in Figure 6 In the example embodiment, SCI 601 and / or 602 may carry information about the cyclic shift to be used for the SCI to be transmitted in resource 603. UEs that may transmit in parallel with resource 603 may select a cyclic shift for their transmission from the remaining cyclic shift values. Excluding the cyclic shift to be used by another UE reduces the potential for collisions between two UEs transmitting in overlapping resources from 25% as described above to 0%. In a collision involving three UEs transmitting in overlapping resources, the potential for collisions may be reduced from 75% to 3 / 9 = 33%. Thus, the various aspects presented herein may provide improvements in PSSCH detection.

[0069] Figure 7An example communication flow 700 between a first UE 702 and a second UE 704 involving indication of cyclic shift information for a DM-RS in a PSCCH is illustrated. The communication can be based on V2X or other D2D-based communication transmitted directly from a transmitting device to a receiving device. In some examples, the communication transmission can be broadcast and received by multiple receiving devices within range of the transmitting device, such as in conjunction with Figure 4 Although this example involves a UE, aspects of the communication flow may also be employed by other devices communicating over a sidelink, such as an RSU, etc. At 706, the UE 702 transmits a first transmission 706 including a PSCCH and a PSSCH, such as a combination of Figure 4 、 Figure 5 and / or Figure 6 As described. The first transmission includes a DM-RS with an applied cyclic shift value and carries information about the cyclic shift in the other transmission. In some examples, the other transmission can be a retransmission of the first transmission 706. In other examples, the first transmission 706 and the other transmission can include an SPS transmission.

[0070] In a first example, the first transmission may include a PSCCH with an SCI indicating whether the cyclic shift value of the other transmission is the same as the cyclic shift of the first transmission 706. The cyclic shift of the first transmission may be randomly selected, for example, from a set of values ​​including {0, 3, 6, 9}, as described above. Information in the first transmission may indicate whether the cyclic shift of the other transmission is the same or randomly selected. For example, the SCI of the first transmission 706 may include a bit indicating cyclic shift information of the other transmission. If the bit has a first value, for example, "1," the SCI may indicate that the cyclic shift has the same value as the cyclic shift of the DM-RS applied to the first transmission. If the bit has a second value, for example, "0," the SCI may indicate that the cyclic shift used for the DM-RS of the other transmission is a randomly selected value. Alternatively, if the bit has a second value, for example, "0," the SCI may indicate that the cyclic shift of the DM-RS of the other transmission is different from the cyclic shift applied in the first transmission, for example, regardless of whether the cyclic shift was randomly selected. In another example, the cyclic shift information may include multiple bits included in the SCI. The cyclic shift information may indicate a cyclic shift value used in another transmission. For example, a set containing 2 bits may use different combinations (eg, 00, 01, 02, 03) to indicate possible cyclic shift values, such as {0, 3, 6, 9}.

[0071] UE 702 may determine whether to indicate the cyclic shift information based on a determined channel busy rate (CBR). For example, if the CBR satisfies a threshold CBR limit, UE 702 may determine to indicate the cyclic shift information when sending the transmission. Additionally or alternatively, UE 702 may determine based on the CBR limit whether to select the cyclic shift for the second transmission randomly or based on the cyclic shift of the first transmission 706. For example, if CBR < CBR limit, UE 702 may determine to randomly select the cyclic shift for the second transmission. If CBR > CBR limit, UE 702 may determine to use the same cyclic shift for the second transmission as that used by UE 702 for the first transmission 706. UE 702 may receive a CBR parameter, for example, in an RRC configuration. In some examples, UE 702 may receive an RRC configuration that indicates the behavior to be used by UE 702 when selecting a cyclic shift.

[0072] At 708, the receiving UE 704 may receive the first transmission and use the information included in the SCI to determine cyclic shift information for another transmission. For example, if the information in the first transmission indicates that the cyclic shift of the second transmission (e.g., transmission 712) has the same value as the first transmission or indicates the actual value of the cyclic shift of the second transmission, the UE 704 may determine the value of the cyclic shift for the second transmission. The UE 704 may determine that the cyclic shift will be randomly selected or will be different from the first transmission, for example, depending on the information carried in the first transmission 706. In some examples, at 710, the UE 704 may exclude the indicated cyclic shift from selection of the cyclic shift value for the sidelink transmission 714 for the second transmission. For example, if the UE 704 determines at 708 that the cyclic shift for transmission 712 will be "3," the UE 704 may select the cyclic shift for the sidelink transmission 714 from the set of values ​​{0, 6, 9} by excluding "3" from the selection. Therefore, even if transmission 712 and transmission 714 are transmitted in overlapping time and / or frequency resources, the two transmissions can avoid using the same cyclic shift value for the associated DM-RS, which can assist the receiving device in detecting / distinguishing the two transmissions and receiving the corresponding data. For example, a third UE 703 can receive transmission 712 from UE 702 and transmission 714 from UE 704 in overlapping time and / or frequency resources, as shown in FIG. Figure 7 As explained in Figure 6Because UE 704 has selected a different cyclic shift for the DM-RS than UE 702 used for transmission 712 (e.g., by excluding the indicated cyclic shift from its selection of its own cyclic shift), third UE 703 may be able to use these different cyclic shifts to distinguish between the two transmissions (e.g., 712 and 714). Example communication diagram 750 shows that third UE 703 receives both transmissions 712 and 714. In addition, UE 703 may be aware of the cyclic shift of transmission 712 based on information about the cyclic shift in another transmission sent at 706.

[0073] Figure 8 800 is a flow chart of a wireless communication method. The method may be performed by a UE, an RSU, or another wireless device communicating based on V2X or other D2D communications. For example, the method may be performed by a UE or a component of a UE (e.g., Figure 1 UE104 in Figure 4 UE 402 in Figure 7 UE 702 in; Figure 3 Device 310 or 350; Figure 10 and Figure 11 Device 1002 / 1002'; and / or Figure 11 The method may be performed by a processing system 1114 in a first transmission, which may include memory and may be the entire UE or a component of the UE. Optional aspects are illustrated with dashed lines. The method may help improve PSSCH performance, improve link management, and / or reduce congestion by providing information about the cyclic shift of the second transmission in the first transmission.

[0074] At 806, the UE transmits a first transmission including a first SCI using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI for a second transmission from the UE. For example, the transmission may be, for example, Figure 10 The first transmission may be performed by the cyclic shift information component 1008 and / or the transmission component 1006 of the device 1002. For example, the first transmission may include a PSCCH transmission including a DM-RS with a first cyclic shift. The first transmission may include a cyclic shift information component 1008 and / or a transmission component 1006 of the device 1002. Figure 7 The first transmitted SCI may include the combination of Figure 5 SCI 502 and / or Figure 6The aspects described in SCI601 or 602 in the first transmission. The first cyclic shift can be randomly selected (e.g., from a set of values ​​such as {0, 3, 6, 9}), and the information can indicate whether the second cyclic shift of the second SCI is the same as the first cyclic shift. For example, a first bit value (e.g., "1") can indicate that the second cyclic shift of the second SCI is the same as the randomly selected cyclic shift, and a second bit value (e.g., "0") can indicate that the second cyclic shift of the second SCI is randomly selected. As another example, a first bit value (e.g., "1") can indicate that the second cyclic shift of the second SCI is the same as the randomly selected cyclic shift, and a second bit value (e.g., "0") can indicate that the second cyclic shift of the second SCI is different from the first cyclic shift. The information may include a single bit of the first SCI in the first transmission. The information may indicate a value for the second cyclic shift of the second SCI. The information may include multiple bits, such as in combination Figure 7 described.

[0075] At 808, the UE transmits a second transmission including a second SCI using a second cyclic shift. For example, the transmission may be composed of Figure 10 The cyclic shift information component 1008 and / or the transmission component 1006 of the device 1002 in the embodiment of the present invention can be performed. The second transmission can be a retransmission of the first transmission. The first transmission and the second transmission can include SPS transmission.

[0076] At 804, the UE may select a second cyclic shift for the second SCI based on the determined CBR. For example, the selection may be made by Figure 10 The selecting component 1010 and / or the transmitting component 1006 of the device 1002 in the embodiment of the present invention can be performed. For example, if the CBR meets the threshold, the UE can select a second cyclic shift of the second SCI that is the same as the first cyclic shift, and if the CBR is lower than the threshold, the second cyclic shift of the second SCI can be selected so that it is different from the first cyclic shift.

[0077] As illustrated at 802, the threshold used by the UE may be the received threshold. Thus, the UE may receive an indication of the threshold, for example, in an RRC configuration. For example, the reception of the threshold may be indicated by, for example, Figure 10 The CBR component 1012 and / or the transport component 1006 of the device 1002 are executed.

[0078] Figure 9 900 is a flow chart of a wireless communication method. The method may be performed by a UE, an RSU, or another wireless device communicating based on V2X or other D2D communications. For example, the method may be performed by a UE or a component of a UE (e.g., Figure 1 UE104 in Figure 4 UE 402 in Figure 7 UE 704 in; Figure 3 Device 310 or 350; Figure 10 or Figure 11 Device 1002 / 1002' in; or Figure 11 The method may be performed by a processing system 1114 in a first transmission, which may include memory and may be the entire UE or a component of the UE. Optional aspects are illustrated with dashed lines. The method may help improve PSSCH performance, improve link management, and / or reduce congestion by providing information about the cyclic shift of the second transmission in the first transmission.

[0079] At 904, the first UE receives a first transmission including a first SCI and having a first cyclic shift from a second UE. For example, the reception may be performed by Figure 10 For example, the first transmission may include a PSCCH transmission including a DM-RS with a first cyclic shift. The first transmission may include a combination of Figure 7 The first transmitted SCI may include the combination of Figure 5 SCI 502 and / or Figure 6 The first cyclic shift may be randomly selected (eg, from a set of values ​​such as {0, 3, 6, 9}).

[0080] At 906, the first UE uses the information in the first SCI to determine cyclic shift information about a second cyclic shift of a second SCI for a second transmission for a second UE. For example, the determination may be made by Figure 10The cyclic shift information component 1008 of the device 1002 in the second UE may be performed. The second transmission may be a retransmission of the first transmission. The first transmission and the second transmission may include an SPS transmission. The first cyclic shift may be randomly selected, and the information may indicate whether the cyclic shift of the second SCI is the same as the first cyclic shift. For example, a first bit value (e.g., "1") may indicate that the second cyclic shift of the second SCI is the same as the randomly selected cyclic shift, and a second bit value (e.g., "0") may indicate that the second cyclic shift of the second SCI is randomly selected. As another example, a first bit value (e.g., "1") may indicate that the second cyclic shift of the second SCI is the same as the randomly selected cyclic shift, and a second bit value (e.g., "0") may indicate that the second cyclic shift of the second SCI is different from the first cyclic shift. The information may include a single bit. The information may indicate a value for the second cyclic shift of the second SCI. The information may include multiple bits. At 906, the first UE may additionally determine the second cyclic shift of the second SCI based on the CBR. For example, if the CBR meets a threshold, the second cyclic shift of the second SCI may be the same as the first cyclic shift, and if the CBR is below the threshold, the second cyclic shift of the second SCI may be different from the first cyclic shift.

[0081] As illustrated at 902, the first UE may receive an indication of the threshold, for example, in an RRC configuration. For example, the reception of the threshold may be initiated by, for example, Figure 10 The CBR component 1012 and / or the transport component 1006 of the device 1002 are executed.

[0082] At 908, the first UE may use the information received in the first SCI to exclude the second cyclic shift from its own selection of cyclic shifts for the SCI used for its own transmission. The SCI of the first UE may be referred to as a third SCI to distinguish it from the first SCI and the second SCI of the second UE. For example, the exclusion may be performed by the selection component 1010 of the device 1002. Figure 7 An example of a UE 704 excluding an indicated cyclic shift is described. For example, if the information indicates that the second cyclic shift is the same as the first cyclic shift, the first UE may exclude the second cyclic shift based on the first cyclic shift. In another example, the first UE may exclude the value of the second cyclic shift based on the information indicating the value of the second cyclic shift.

[0083] Figure 10is a conceptual data flow diagram 1000 illustrating data flow between different devices / components in an example device 1002. The device may be a UE or a component of a UE. In other examples, the device may include an RSU or a component of an RSU, or another device that communicates based on V2X or D2D communication. The device includes a receiving component 1004 that receives communications (such as V2X communications) from other UEs 1050, and a transmitting component 1006 that transmits communications (such as V2X communications) to other UEs 1050. The device 1002 includes a cyclic shift information component 1008 that is configured to include a first transmission of a first SCI using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI for a second transmission from the UE, for example, as combined Figure 8 The device 1002 includes a selection component 1010 configured to select a second cyclic shift of a second SCI, for example, as described in conjunction with Figure 8 The apparatus includes a CBR component 1012 configured to receive an indication of a threshold, for example, as described in conjunction with Figure 8 802 and / or Figure 9 If device 1002 is a receiving device, cyclic shift information component 1008 can be configured to receive a first transmission from a second UE 1050, the first transmission including a first SCI and having a first cyclic shift and having information about a cyclic shift of a second SCI. Cyclic shift information component 1008 can be configured to use the information to determine cyclic shift information about the second transmission, such as whether the cyclic shift is the same as the cyclic shift of the first transmission, whether the cyclic shift is different, whether the cyclic shift is randomly selected, the value of the cyclic shift, etc. Selection component 1010 can be configured to exclude the second cyclic shift from the selection, such as described in conjunction with 908.

[0084] The device may include additional components that perform Figure 8 and / or Figure 9 Each box of the algorithm in the aforementioned flowchart, and the combination Figure 7 In this way, Figure 8 and / or Figure 9 Each box in the aforementioned flowchart, and the combination Figure 7 The various aspects described may be performed by components, and the apparatus may include one or more of those components. These components may be one or more hardware components specifically configured to perform the described process / algorithm, implemented by a processor configured to perform the described process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0085] Figure 11FIG11 is a diagram illustrating an example of a hardware implementation for a device 1002′ employing a processing system 1114. The processing system 1114 may be implemented with a bus architecture generally represented by a bus 1124. Depending on the specific application and overall design constraints of the processing system 1114, the bus 1124 may include any number of interconnecting buses and bridges. The bus 1124 links together various circuits including one or more processors and / or hardware components (represented by the processor 1104, components 1004, 1006, 1008, 1010, 1012, and computer-readable medium / memory 1106). The bus 1124 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, therefore, will not be described further.

[0086] Processing system 1114 may be coupled to transceiver 1110. Transceiver 1110 is coupled to one or more antennas 1120. Transceiver 1110 provides a means for communicating with various other devices via a transmission medium. Transceiver 1110 receives signals from the one or more antennas 1120, extracts information from the received signals, and provides the extracted information to processing system 1114 (specifically, receiving component 1004). In addition, transceiver 1110 receives information from processing system 1114 (specifically, transmitting component 1006) and generates signals to be applied to one or more antennas 1120 based on the received information. Processing system 1114 includes processor 1104 coupled to computer-readable medium / memory 1106. Processor 1104 is responsible for general processing, including the execution of software stored on computer-readable medium / memory 1106. When executed by processor 1104, this software enables processing system 1114 to perform the various functions described above for any particular device. The computer-readable medium / memory 1106 may also be used to store data that is manipulated by the processor 1104 when executing software. The processing system 1114 further includes at least one of the components 1004, 1006, 1008, 1010, 1012. These components may be software components running in the processor 1104, software components resident / stored in the computer-readable medium / memory 1106, one or more hardware components coupled to the processor 1104, or some combination thereof. The processing system 1114 may be a component of the device 310 or the device 350 and may include the memories 376, 360 and / or at least one of the TX processors 316, 368, the RX processors 370, 356, and the controllers / processors 375, 359. Alternatively, the processing system 1114 may be the entire UE (e.g., see Figure 3 device 310 or 350).

[0087] In one configuration, an apparatus 1002 / 1002′ for wireless communication includes means for transmitting a first transmission including first sidelink control information (SCI) using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI for a second transmission from a UE, e.g., as described in conjunction with Figure 8 and a device for transmitting a second transmission including a second SCI using a second cyclic shift, for example, as described in conjunction with Figure 8 The apparatus 1002 may further include means for selecting a second cyclic shift of the second SCI based on the CBR, for example, as described in conjunction with Figure 8 The apparatus 1002 / 1002' may further include means for receiving an indication of a threshold value in an RRC configuration, for example, as described in conjunction with Figure 8 The apparatus 1002 / 1002′ may further include means for receiving a first transmission comprising a first SCI having a first cyclic shift from a second UE, for example, as described in conjunction with Figure 9 The apparatus 1002 / 1002′ may further include means for determining cyclic shift information about a second cyclic shift of a second SCI for a second transmission from the UE using information in the first SCI, for example, as described in conjunction with Figure 9 The apparatus 1002 / 1002′ may further include means for using the information received in the first SCI to exclude the second cyclic shift from its selection of cyclic shifts for the SCI in its own transmission, e.g., as described in conjunction with Figure 9 908 in . The aforementioned means may be one or more components of the aforementioned components of device 1002 and / or the processing system 1114 of device 1002' configured to perform the functions recited by the aforementioned means. As previously described, the processing system 1114 may include TX processors 316, 368, RX processors 370, 356, and controllers / processors 375, 359. Thus, in one configuration, the aforementioned means may be TX processors 316, 368, RX processors 370, 356, and controllers / processors 375, 359 configured to perform the functions recited by the aforementioned means.

[0088] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowcharts is an illustration of an example approach. It should be understood that the specific order or hierarchy of the blocks in these process / flowcharts can be rearranged based on design preferences. In addition, some blocks can be combined or omitted. The accompanying method claims present the elements of the various blocks in an example order and are not meant to be limited to the specific order or hierarchy presented.

[0089] The following examples are merely illustrative, and aspects thereof may be combined with aspects of other embodiments or teachings described herein without limitation.

[0090] Example 1 is a method for wireless communication at a UE, comprising: transmitting a first transmission including a first SCI using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI for a second transmission from the UE; and transmitting a second transmission including the second SCI using a second cyclic shift.

[0091] In Example 2, the method of Example 1 further includes: the second transmission is a retransmission of the first transmission.

[0092] In Example 3, the method of Example 1 or Example 2 further includes: the first transmission and the second transmission being SPS transmissions.

[0093] In Example 4, the method of any one of Examples 1-3 further includes: the first cyclic shift is randomly selected, and the information indicates whether the second cyclic shift of the second SCI is the same as the first cyclic shift.

[0094] In Example 5, the method of any one of Examples 1-4 further includes the first bit value indicating that the second cyclic shift of the second SCI is the same as the first cyclic shift, and the second bit value indicating that the second cyclic shift of the second SCI is randomly selected.

[0095] In Example 6, the method of any one of Examples 1-5 further includes: the first bit value indicating that the second cyclic shift of the second SCI is the same as the first cyclic shift, and the second bit value indicating that the second cyclic shift of the second SCI is different from the first cyclic shift.

[0096] In Example 7, the method of any one of Examples 1-6 further includes: the information comprising a single bit.

[0097] In Example 8, the method of any one of Examples 1-7 further includes: the information indicating a value of a second cyclic shift for the second SCI.

[0098] In Example 9, the method of any one of Examples 1-8 further includes: the information comprising a plurality of bits.

[0099] In Example 10, the method of any one of Examples 1-9 further includes selecting a second cyclic shift of the second SCI based on the CBR.

[0100] In Example 11, the method of any one of Examples 1-10 further includes: if the CBR satisfies a threshold, the second cyclic shift of the second SCI is the same as the first cyclic shift, and if the CBR is below the threshold, the second cyclic shift of the second SCI is different from the first cyclic shift.

[0101] In Example 12, the method of any one of Examples 1-11 further includes receiving an indication of the threshold in an RRC configuration.

[0102] Example 13 is a device comprising one or more processors and one or more memories in electronic communication with the one or more processors, the one or more memories storing instructions executable by the one or more processors to cause the device to implement a method as in any of Examples 1-12.

[0103] Example 14 is a system or apparatus comprising means for implementing the method as in any one of Examples 1-12 or implementing the apparatus as in any one of Examples 1-12.

[0104] Example 15 is a non-transitory computer-readable medium storing instructions executable by one or more processors to cause the one or more processors to implement the method as in any of Examples 1-12.

[0105] Example 16 is a method for wireless communication at a first UE, comprising: receiving a first transmission including a first SCI having a first cyclic shift from a second UE; and using information in the first SCI to determine cyclic shift information about a second cyclic shift of a second SCI for a second transmission from the UE.

[0106] In Example 17, the method of Example 16 further includes: the second transmission is a retransmission of the first transmission.

[0107] In Example 18, the method of Example 16 or Example 17 further includes: the first transmission and the second transmission are SPS transmissions.

[0108] In Example 19, the method of any one of Examples 16-18 further includes excluding the second cyclic shift from selection of a third SCI from the first UE using the information received in the first SCI.

[0109] In Example 20, the method of any one of Examples 16-19 further includes, if the information indicates that the second cyclic shift is the same as the first cyclic shift, excluding, by the first UE, the second cyclic shift based on the first cyclic shift.

[0110] In Example 21, the method of any one of Examples 16-20 further includes the first UE excluding the value of the second cyclic shift based on the information indicating the value of the second cyclic shift.

[0111] In Example 22, the method of any one of Examples 16-21 further includes: the first cyclic shift being randomly selected, and the information indicating whether the second cyclic shift of the second SCI is the same as the first cyclic shift.

[0112] In Example 23, the method of any one of Examples 16-22 further includes the first bit value indicating that the second cyclic shift of the second SCI is the same as the first cyclic shift, and the second bit value indicating that the second cyclic shift of the second SCI is randomly selected.

[0113] In Example 24, the method of any one of Examples 16-23 further includes the first bit value indicating that the second cyclic shift of the second SCI is the same as the first cyclic shift, and the second bit value indicating that the second cyclic shift of the second SCI is different from the first cyclic shift.

[0114] In Example 25, the method of any one of Examples 16-24 further includes: the information comprising a single bit.

[0115] In Example 26, the method of any one of Examples 16-25 further includes: the information indicating a value of a second cyclic shift for the second SCI.

[0116] In Example 27, the method of any one of Examples 16-26 further includes: the information comprising a plurality of bits.

[0117] In Example 28, the method of any one of Examples 16-27 further includes determining a second cyclic shift of the second SCI based on the CBR.

[0118] In Example 29, the method of any one of Examples 16-28 further includes: if the CBR satisfies a threshold, the second cyclic shift of the second SCI is the same as the first cyclic shift, and if the CBR is below the threshold, the second cyclic shift of the second SCI is different from the first cyclic shift.

[0119] In Example 30, the method of any one of Examples 16-29 further includes receiving an indication of the threshold in an RRC configuration.

[0120] Example 31 is a device comprising one or more processors and one or more memories in electronic communication with the one or more processors, the one or more memories storing instructions executable by the one or more processors to cause the device to implement a method as in any of Examples 16-30.

[0121] Example 32 is a system or apparatus comprising means for implementing the method as in any of Examples 16-30 or implementing the apparatus as in any of Examples 16-30.

[0122] Example 33 is a non-transitory computer-readable medium storing instructions executable by one or more processors to cause the one or more processors to implement the method as in any of Examples 16-30.

[0123] 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 universal principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but rather to be granted the full scope consistent with the language of the claims, wherein singular references to elements are not intended to mean "one and only one," but rather "one or more," unless otherwise specified. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as superior to or surpassing other aspects. Unless otherwise specifically stated, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" include any combination of A, B, and / or C, and may include multiple As, multiple Bs, or multiple Cs. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of the various aspects described throughout this disclosure to those of ordinary skill in the art now or hereafter known are expressly incorporated herein by reference and are intended to be encompassed by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is expressly recited in the claims. The terms "module," "mechanism," "element," "device," etc. are not intended to be a substitute for the term "means." As such, no claim element should be construed as means-plus-function unless the element is expressly recited using the phrase "means for."

Claims

1. A method for wireless communication at a user equipment (UE), comprising: transmitting a first transmission including first sidelink control information (SCI) using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI for a second transmission from the UE, wherein the second cyclic shift is to be excluded from selection by a receiving UE for a third SCI; as well as The second transmission including the second SCI is transmitted using the second cyclic shift. The method of claim 1 , wherein the second transmission is a retransmission of the first transmission.

3. The method of claim 1, wherein the first transmission and the second transmission are semi-persistently scheduled (SPS) transmissions.

4. The method of claim 1, wherein the first cyclic shift is randomly selected, and the information indicates whether the second cyclic shift of the second SCI is the same as the first cyclic shift. 5 . The method of claim 4 , wherein a first bit value of the information indicates that the second cyclic shift of the second SCI is the same as the first cyclic shift, and a second bit value of the information indicates that the second cyclic shift of the second SCI is randomly selected.

6. The method of claim 1, wherein a first bit value of the information indicates that the second cyclic shift of the second SCI is the same as the first cyclic shift, and a second bit value of the information indicates that the second cyclic shift of the second SCI is different from the first cyclic shift.

7. The method of claim 1, wherein the information comprises a single bit.

8. The method of claim 1, wherein the information indicates a value of the second cyclic shift for the second SCI.

9. The method of claim 8, wherein the information comprises a plurality of bits.

10. The method of claim 1, further comprising: The second cyclic shift of the second SCI is selected based on a channel busy rate (CBR).

11. The method of claim 10, wherein if the CBR satisfies a threshold, the second cyclic shift of the second SCI is the same as the first cyclic shift, and if the CBR is below the threshold, the second cyclic shift of the second SCI is different from the first cyclic shift.

12. The method of claim 11, further comprising: An indication of the threshold is received in a radio resource control (RRC) configuration.

13. A method of wireless communication at a first user equipment (UE), comprising: receiving, from a second UE, a first transmission comprising first sidelink control information (SCI) having a first cyclic shift; determining, using information in the first SCI, cyclic shift information regarding a second cyclic shift of a second SCI for a second transmission from the UE; as well as The second cyclic shift is excluded from selection for a third SCI from the first UE using the information received in the first SCI. The method of claim 13 , wherein the second transmission is a retransmission of the first transmission.

15. The method of claim 13, wherein the first transmission and the second transmission are semi-persistently scheduled (SPS) transmissions. 16 . The method of claim 13 , wherein if the information indicates that the second cyclic shift is the same as the first cyclic shift, the first UE excludes the second cyclic shift based on the first cyclic shift.

17. The method of claim 13, wherein the first UE excludes the value of the second cyclic shift based on the information indicating the value of the second cyclic shift.

18. The method of claim 13, wherein the first cyclic shift is randomly selected, and the information indicates whether the second cyclic shift of the second SCI is the same as the first cyclic shift.

19. The method of claim 18, wherein a first bit value of the information indicates that the second cyclic shift of the second SCI is the same as the first cyclic shift, and a second bit value of the information indicates that the second cyclic shift of the second SCI is randomly selected.

20. The method of claim 13, wherein a first bit value of the information indicates that the second cyclic shift of the second SCI is the same as the first cyclic shift, and a second bit value of the information indicates that the second cyclic shift of the second SCI is different from the first cyclic shift.

21. The method of claim 13, wherein the information comprises a single bit.

22. The method of claim 13, wherein the information indicates a value of the second cyclic shift for the second SCI.

23. The method of claim 22, wherein the information comprises a plurality of bits.

24. The method of claim 13, further comprising: The second cyclic shift of the second SCI is determined based on a channel busy rate (CBR).

25. The method of claim 24, wherein if the CBR satisfies a threshold, the second cyclic shift of the second SCI is the same as the first cyclic shift, and if the CBR is below the threshold, the second cyclic shift of the second SCI is different from the first cyclic shift.

26. The method of claim 25, further comprising: An indication of the threshold is received in a radio resource control (RRC) configuration.

27. An apparatus for wireless communication at a user equipment (UE), comprising: Memory; as well as at least one processor coupled to the memory and configured to: transmitting a first transmission including first sidelink control information (SCI) using a first cyclic shift, wherein the first SCI includes information about a second cyclic shift of a second SCI for a second transmission from the UE, wherein the second cyclic shift is to be excluded from selection by a receiving UE for a third SCI; as well as The second transmission including the second SCI is transmitted using the second cyclic shift.

28. An apparatus for wireless communication at a user equipment (UE), comprising: Memory; as well as At least one processor is coupled to the memory and configured to perform the method of any one of claims 2-12.

29. An apparatus for wireless communication at a first user equipment (UE), comprising: Memory; as well as at least one processor coupled to the memory and configured to: receiving, from a second UE, a first transmission comprising first sidelink control information (SCI) having a first cyclic shift; determining, using information in the first SCI, cyclic shift information regarding a second cyclic shift of a second SCI for a second transmission from the UE; as well as The second cyclic shift is excluded from selection for a third SCI from the first UE using the information received in the first SCI.

30. An apparatus for wireless communication at a first user equipment (UE), comprising: Memory; as well as At least one processor is coupled to the memory and configured to perform the method of any one of claims 14-26.

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