Method and apparatus for timing advance (TA) determination for sidelink (SL) communication

Abstract

This disclosure provides apparatus, methods, processing systems, and computer-readable media for determining timing advance (TA) used in side link (SL) communications. A method that can be performed by a transceiver (TX) user equipment (UE) includes: applying a first TA when transmitting at least a first SL transmission to a receiving (RX) UE, and applying a second TA when transmitting at least a second SL transmission to an RX UE.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Patent Application No. 17 / 117,746, filed on December 10, 2020, which has been assigned to the assignee and the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] Various aspects of this disclosure relate to wireless communications, and more specifically, to timing adjustments for processing side link (SL) communications. Background Technology

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. These wireless communication systems can employ multiple access technologies that enable communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include 3GPP Long Term Evolution (LTE) systems, LTE-A systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name just a few.

[0005] In some examples, a wireless multiple access communication system may include multiple base stations (BSs), each capable of simultaneously supporting communication for multiple communication devices (also referred to as user equipment (UE)). In LTE or LTE-A networks, a set of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in next-generation, new radio (NR), or 5G networks), a wireless multiple access communication system may include multiple distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmit / receive points (TRPs), etc.) communicating with multiple central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), wherein a set of one or more DUs communicating with a CU may define an access node (e.g., which may be referred to as a BS, a 5G NB, a next-generation node B (gNB or gNodeB), a transmit / receive point (TRP), etc.). A BS or DU can communicate with a group of UEs on downlink channels (e.g., for transmissions from the BS or DU to the UE) and uplink channels (e.g., for transmissions from the UE to the BS or DU).

[0006] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, national, regional, and even global levels. New radios (e.g., 5G NR) are an example of emerging telecommunications standards. NR is a set of enhancements to the LTE mobile standard released by 3GPP. NR is designed to better support mobile broadband internet access by improving spectrum efficiency, reducing costs, improving service, utilizing new spectrum, and better integrating with other open standards using OFDMA and cyclic prefixes (CP) on both downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0007] Sidelink (SL) communication typically refers to communication between devices (e.g., between UEs). As the demand for mobile broadband access continues to increase, the need for improvements in SL communication is also growing. Summary of the Invention

[0008] The systems, methods, and apparatuses of this disclosure have several aspects, none of which is solely responsible for their desired properties. Without limiting the scope of this disclosure as set forth in the following claims, some features will now be briefly discussed. Upon consideration of this discussion, and particularly after reading the section entitled "Detailed Description," it will be understood how the features of this disclosure provide the advantages of including improved device-to-device communication in a wireless network.

[0009] Certain aspects of this disclosure provide a method for wireless communication by a transmitting (TX) user equipment (UE). The method typically includes applying a first timing advance (TA) when transmitting at least a first side-link (SL) transmission to a receiving (RX) UE. The method typically includes applying a second TA when transmitting at least a second SL transmission to the RX UE.

[0010] Certain aspects of this disclosure provide a method for wireless communication by an RX UE. The method typically includes obtaining an indication of a TA from the TX UE during a first SL transmission. The method also typically includes applying the TA upon receiving at least a second SL transmission from the TX UE.

[0011] Some aspects of this disclosure provide a TX UE. The TX UE typically includes at least one antenna and a processing system configured to apply a first TA when transmitting at least a first SL transmission to the RX UE via the at least one antenna, and to apply a second TA when transmitting at least a second SL transmission to the RX UE via the at least one antenna.

[0012] Certain aspects of this disclosure provide an RX UE. The RX UE typically includes a receiver and a processing system, the receiver being configured to receive an indication of a TA from a TX UE during a first SL transmission, and the processing system being configured to apply the TA when at least a second SL transmission is received from the TX UE.

[0013] Some aspects of this disclosure provide a TX UE. The TX UE typically includes: a unit for providing at least one antenna, a unit for applying a first TA when transmitting at least a first SL transmission to the RX UE via at least one antenna, and a unit for applying a second TA when transmitting at least a second SL transmission to the RX UE via at least one antenna.

[0014] Some aspects of this disclosure provide an RX UE. The RX UE typically includes: a unit for receiving an indication of a TA from a TX UE during a first SL transmission, and a unit for applying the TA when at least a second SL transmission is received from the TX UE.

[0015] Certain aspects of this disclosure provide a computer-readable medium for wireless communication by a TX UE. The computer-readable medium typically includes code capable of performing the following operations: applying a first TA when at least a first SL transmission is sent to the RX UE, and applying a second TA when at least a second SL transmission is sent to the RX UE.

[0016] Certain aspects of this disclosure provide a computer-readable medium for wireless communication by an RX UE. The computer-readable medium typically includes code capable of: receiving an instruction regarding a TA from the TX UE during a first SL transmission, and applying the TA when at least a second SL transmission is received from the TX UE.

[0017] This disclosure also provides various UEs, network entities, devices, units, and computer-readable media corresponding to the methods and operations described above.

[0018] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and specifically pointed out in the claims. The following description and drawings set forth certain illustrative features of one or more aspects in detail. However, these features indicate only a few of the various ways in which the principles of each aspect can be employed. Attached Figure Description

[0019] Therefore, the above-described features of this disclosure can be understood in detail by referring to a more specific description of the aspects briefly outlined above, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and should not be construed as limiting its scope, as the specification may allow for other equally valid aspects.

[0020] Figure 1 This is a block diagram conceptually illustrating certain aspects of an example telecommunications system based on this disclosure.

[0021] Figure 2 This is a block diagram conceptually illustrating the design of an example base station (BS) and user equipment (UE) according to certain aspects of this disclosure.

[0022] Figure 3 An example of a frame structure for a new radio (NR) system is shown, according to certain aspects of this disclosure.

[0023] Figure 4A and Figure 4B Two modes of side link (SL) communication according to certain aspects of this disclosure are shown.

[0024] Figure 5 An example relationship between LTE downlink (DL) timing and uplink (UL) timing during a random access channel (RACH) procedure is shown, according to certain aspects of this disclosure.

[0025] Figure 6 This is a flowchart illustrating example operations for wireless communication by a transmitting (TX) UE in accordance with certain aspects of this disclosure.

[0026] Figure 7 This is a flowchart illustrating example operations for wireless communication by a receiving party (RX) UE in accordance with certain aspects of this disclosure.

[0027] Figure 8A and Figure 8B The nominal timeslot format for SL data transmission (without TA) and the actual timeslot format for SL data transmission (with TA) according to certain aspects of this disclosure are shown respectively.

[0028] Figure 9 This is an exemplary transmission timeline illustrating the application of TA in SL communications according to certain aspects of this disclosure.

[0029] Figure 10 This is an exemplary transmission timeline illustrating the transmission and resource reservation of an SL device according to aspects of this disclosure.

[0030] Figure 11 The present disclosure illustrates a communication device that may include various components configured to perform operations using the techniques disclosed herein.

[0031] Figure 12 The present disclosure illustrates a communication device that may include various components configured to perform the operations of the techniques disclosed herein.

[0032] For ease of understanding, the same reference numerals are used where possible to denote the same elements common in the figures. It is conceivable that elements disclosed in one aspect can be advantageously used in other aspects without specific description. Detailed Implementation

[0033] This disclosure provides apparatus, methods, processing systems, and computer-readable media for determining timing advance (TA) used in side link (SL) communications. For example, in some cases, a sending (TX) user equipment (UE) can determine at least one of a first TA or a second TA to be applied when transmitting at least a first SL transmission and at least a second SL transmission to a receiving (RX) UE, respectively.

[0034] The following description provides examples determined by a TA for SL communication and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements discussed without departing from the scope of this disclosure. Various processes or components may be omitted, substituted, or added as appropriate in various examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Moreover, features described for some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement the apparatus or the method may be practiced. Furthermore, the scope of this disclosure is intended to cover such apparatus or methods implemented using other structures, functions, or structures and functions that complement or replace the various aspects of this disclosure set forth herein. It should be understood that any aspect of the disclosure herein may be embodied by one or more elements of the claims. The term “exemplary” as used herein means “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

[0035] The technologies described in this article can be used in a variety of wireless communication technologies such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other networks. The terms "network" and "system" are generally used interchangeably. CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 encompasses the IS-2000, IS-95, and IS-856 standards. TDMA networks can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, and others. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS).

[0036] New Radio (NR) is an emerging wireless communication technology being developed in collaboration with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are versions of UMTS using E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). The technologies described herein can be used with the wireless networks and radio technologies mentioned herein, as well as other wireless networks and radio technologies. For clarity, while this document may use terms commonly associated with 3G and / or 4G wireless technologies to describe aspects, aspects of this disclosure can be applied to other generation-based communication systems, such as 5G and later technologies, including NR technology.

[0037] New radio (NR) access (e.g., 5G technology) can support a variety of wireless communication services, such as enhanced mobile broadband (eMBB) for broadband (e.g., 80 MHz or higher), millimeter wave (mmW) for high carrier frequencies (e.g., 25 GHz or higher), massive machine-type communication (mMTC) for non-backward-compatible MTC technologies, and / or mission-critical ultra-reliable low-latency communication (URLLC). These services can include latency and reliability requirements. These services can also have different transmission time intervals (TTIs) to meet corresponding quality of service (QoS) requirements. Furthermore, these services can coexist in the same subframe.

[0038] Example wireless communication system

[0039] Figure 1 An example wireless communication network 100 in which aspects of this disclosure can be implemented is shown. For example, the wireless communication network may include a BS 110 and a UE 120 configured to determine timing advance (TA) for lateral link (SL) communication. In some examples, the UE 120 may be configured for SL communication. Figure 1 As shown, one or more UEs 120 (e.g., transmitting (TX) UEs) of the wireless communication network 100 can be configured to perform (or have a timing advance (TA) manager 112 configured to perform or cause the UE to perform) as shown below. Figure 6 Operation 600 is described. Additionally, one or more UEs 120 (e.g., receiver (RX) UEs) of the wireless communication network 100 can be configured to perform (or have a TA manager 122 configured to perform or cause the UE to perform) as described below. Figure 7 The operation described is 700.

[0040] For example, such as Figure 1 As shown, according to the aspects described herein, one or more of UEs 120 may have a TA manager 112, which can be configured to apply a first TA when at least a first side link (SL) transmission is sent to the RX UE, and to apply a second TA when at least a second SL transmission is sent to the RX UE. Similarly, according to the aspects described herein, one or more UEs 120 may have a TA manager 122, which can be configured to obtain an indication of the TA from the TX UE during the first SL transmission, and to apply the TA when at least a second SL transmission is received from the TX UE.

[0041] The wireless communication network 100 can be an NR system (e.g., a 5G NR network). For example... Figure 1 As shown, the wireless communication network 100 can communicate with the core network 132. The core network 132 can communicate with one or more base stations (BS) and / or user equipment (UE) 120 in the wireless communication network 100 via one or more interfaces.

[0042] like Figure 1As shown, the wireless communication network 100 may include several BS110a-z (each BS is also individually referred to herein as BS110 or collectively as BS110) and other network entities. In one aspect of this disclosure, a roadside serving unit (RSU) may be considered a type of BS, and BS110 may be referred to as an RSU. BS110 may provide communication coverage for a specific geographic area (sometimes referred to as a “cell”), which may be stationary or mobile depending on the location of the mobile BS110. In some examples, BS110 may be interconnected with each other and / or interconnected to one or more other BSs or network nodes (not shown in the figure) in the wireless communication network 100 via various types of backhaul interfaces (e.g., direct physical connection, wireless connection, virtual network, etc.) using any suitable transport network. Figure 1 In the example shown, such as Figure 1 As shown, BS110a, BS110b, and BS110c can be macro BSs corresponding to macro cells 102a, 102b, and 102c, respectively. BS110x can be a pico BS corresponding to pico cell 102x. BS110y and 110z can be femto BSs corresponding to femto cells 102y and 102z, respectively. A BS can support one or more cells.

[0043] Network controller 130 can be coupled to a group of BS110s and provide coordination and control for these BS110s. Network controller 130 can communicate with the BS110s via backhaul. The BS110s can also communicate with each other (e.g., directly or indirectly) via wireless or wired backhaul.

[0044] In the wireless communication network 100, BS110 communicates with user equipment (UE) 120a-y (each UE is also referred to herein individually as UE 120 or collectively as UE 120). UE 120 (e.g., 120x, 120y, etc.) may be distributed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile.

[0045] The wireless communication network 100 may also include a relay station (e.g., relay station 110r), also referred to as a relay, which receives data and / or other information transmissions from an upstream station (e.g., BS110a or UE 120r) and sends data and / or other information transmissions to a downstream station (e.g., UE 120 or BS110), or relays transmissions between UEs 120 to facilitate communication between devices.

[0046] UE 120 (e.g., 120x, y, etc.) may be distributed throughout the wireless communication network 100, and each UE may be stationary or mobile. UE may also be referred to as a mobile station, terminal, access terminal, user unit, station, client equipment (CPE), cellular phone, smartphone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical apparatus, biometric sensor / device, such as smartwatch, smart clothing, smart glasses, smart bracelet, smart jewelry (e.g., smart ring, smart bracelet, etc.), wearable device, entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, GPS device, or any other suitable device configured to communicate via wireless or wired media. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTCUE include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with the BS, another device (e.g., a remote device), or some other entity. Wireless nodes can, for example, provide connectivity to or from a network (e.g., a wide area network such as the Internet or cellular networks) via wired or wireless communication links. Some UEs can be considered Internet of Things (IoT) devices, which can be narrowband IoT (NB-IoT) devices.

[0047] Some wireless networks (e.g., LTE) use Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and Single-Carrier Frequency Division Multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are often also referred to as tones, frequency bands, etc. Each subcarrier can be modulated with data. Typically, modulation symbols are transmitted in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the subcarrier spacing could be 15 kHz, and the minimum resource allocation (called a "resource block" (RB)) could be 12 subcarriers (or 180 kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, the nominal Fast Fourier Transform (FFT) size could be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth can also be divided into subbands. For example, a subband can cover 1.08MHz (i.e., 6 resource blocks), and for system bandwidths of 1.25, 2.5, 5, 10, or 20MHz, there can be 1, 2, 4, 8, or 16 subbands respectively.

[0048] While the aspects of the examples described herein may be associated with LTE technology, aspects of this disclosure are applicable to other wireless communication systems (e.g., NR). NR can utilize OFDM with CP on both the uplink and downlink, and includes support for half-duplex operation using TDD. Beamforming can be supported, and beam direction can be dynamically configured. MIMO transmission with precoding can also be supported. MIMO configuration in DL can support up to 8 transmit antennas with up to 8 streams and up to 2 streams per UE for multilayer DL transmission. Multilayer transmission with up to 2 streams per UE can be supported. Aggregation of multiple cells can support up to 8 serving cells.

[0049] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication between some or all devices and apparatuses within its service area or cell. The scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entity uses the resources allocated by the scheduling entity. A base station is not the only entity that can act as a scheduling entity. In some examples, a UE can act as a scheduling entity and can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs can utilize the resources scheduled by that UE for wireless communication. In some examples, a UE can act as a scheduling entity in a point-to-point (P2P) network and / or in a mesh network. In the mesh network example, in addition to communicating with a scheduling entity, UEs can also communicate directly with each other.

[0050] exist Figure 1 In the diagram, a solid line with a double arrow indicates the desired transmission between the UE and the serving BS, which is the BS designated to serve the UE on the downlink and / or uplink. A thin dashed line with a double arrow indicates interference transmission between the UE and the BS.

[0051] Figure 2 The BS110a and UE 120a are shown (e.g.) Figure 1 The example components shown herein can be used to implement aspects of this disclosure. For example, antenna 252, processor 266, processor 258, processor 264, and / or controller / processor 280 of UE 120a can be used to perform the functions described herein. Figure 6 and Figure 7 The various techniques and methods described herein. Similarly, the antenna 232, processor 220, processor 230, processor 238 and / or controller / processor 240 of the BS110a can be used to perform the various techniques and methods described herein.

[0052] At BS110a, the transmit processor 220 can receive data from data source 212 and control information from controller / processor 240. The control information can be used for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), Group Common PDCCH (GC PDCCH), etc. Data can be used for the Physical Downlink Shared Channel (PDSCH), etc. Processor 220 can process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor 220 can also generate reference symbols, for example, for the Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Channel State Information Reference Signal (CSI-RS). Transmit (TX) Multiple-Input Multiple-Output (MIMO) processor 230 can perform spatial processing (e.g., precoding, if applicable) on the data symbols, control symbols, and / or reference symbols, and can provide the output symbol stream to modulators (MODs) 232a to 232t. Each modulator 232 can process the corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator can further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 232a to 232t can be transmitted via antennas 234a to 234t, respectively.

[0053] At UE 120a, antennas 252a to 252r can receive downlink signals from BS 110a and can provide received signals to demodulators (DEMODs) in transceivers 254a to 254r respectively. Each demodulator 254 can adjust (e.g., filter, amplify, downconvert, and digitize) its respective received signal to obtain an input sample. Each demodulator can further process the input sample (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 can obtain received symbols (if applicable) from all demodulators 254a to 254r, perform MIMO detection on the received symbols, and provide the detected symbols. Receiver processor 258 can process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120a to data sink 260, and provide decoded control information to controller / processor 280.

[0054] On the uplink, at UE 120a, transmit processor 264 can receive and process data from data source 262 (e.g., for the Physical Uplink Shared Channel (PUSCH)) and control information from controller / processor 280 (e.g., for the Physical Uplink Control Channel (PUCCH)). Transmit processor 264 can also generate reference symbols for reference signals (RS) (e.g., for sounding reference signals (SRS)). Symbols from transmit processor 264 can be pre-coded (if possible) by TX MIMO processor 266, further processed by modulators in transceivers 254a to 254r (e.g., for SC-FDM, etc.), and transmitted to BS 110a. At BS 110a, uplink signals from UE 120a can be received by antenna 234, processed by modulator 232, detected by MIMO detector 236 (if possible), and further processed by receive processor 238 to obtain decoded data and control information transmitted by UE 120a. The receiver processor 238 can provide the decoded data to the data sink 239 and the decoded control information to the controller / processor 240.

[0055] NR can utilize Orthogonal Frequency Division Multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and / or downlink, and / or single-carrier frequency division multiplexing (SC-FDM) on the uplink. NR can support half-duplex operation using time division duplex (TDD). OFDM and SC-FDM divide the system bandwidth into multiple orthogonal subcarriers, which are often referred to as tones, frequency bands, etc. Each subcarrier can be modulated with data. Modulation symbols can be transmitted using OFDM in the frequency domain and SC-FDM in the time domain. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers can depend on the system bandwidth. An NR resource block (RB) can be 12 consecutive frequency subcarriers. NR can support a basic subcarrier spacing (SCS) of 15 kHz, and other SCSs (e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc.) can be defined for the basic SCS. The system bandwidth can also be divided into subbands. For example, a subband can cover multiple RBs.

[0056] In NR, a subframe is 1ms, but the basic TTI is called a time slot. Figure 3This is a diagram illustrating an example of frame format 300 for NR. The transmission timeline for each of the downlink and uplink can be divided into units of radio frames. Each radio frame can have a predetermined duration (e.g., 10 ms) and can be divided into 10 subframes, each 1 ms and having indices 0 to 9. Each subframe can include a variable number of time slots (e.g., 1, 2, 4, 8, 16, ... time slots), depending on the SCS. Each time slot can include a variable number of symbol periods (e.g., 7 or 14 symbols), depending on the subcarrier spacing. The symbol periods in each time slot can be assigned indices. A mini-time slot, which can be referred to as a sub-time slot structure, refers to a transmission time interval with a duration less than one time slot (e.g., 2, 3, or 4 symbols). Each symbol in a time slot can indicate the link direction used for data transmission (e.g., DL, UL, or flexible), and the link direction can be dynamically switched for each subframe. The link direction can be based on the time slot format. Each time slot can include DL / UL data and DL / UL control information.

[0057] In some scenarios, two or more dependent entities (e.g., UEs) can communicate with each other using sidelink signals. Practical applications of such sidelink communication can include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communication, Internet of Things (IoE) communication, IoT communication, mission-critical meshes, and / or various other suitable applications. Typically, an SL signal can refer to a signal transmitted from one dependent entity (e.g., UE 1) to another dependent entity (e.g., UE 2) without relaying the communication through a scheduling entity (e.g., a UE or BS), even if that scheduling entity may be used for scheduling and / or control purposes. In some examples, licensed spectrum (unlike wireless local area networks (WLANs), which typically use unlicensed spectrum) can be used to transmit SL signals.

[0058] Various SL channels can be used for SL communication, including the Physical Side Link Discovery Channel (PSDCH), Physical Side Link Control Channel (PSCCH), Physical Side Link Shared Channel (PSSCH), and Physical Side Link Feedback Channel (PSFCH). The PSDCH can carry a discovery expression that enables nearby devices to discover each other. The PSCCH can carry control signaling, such as SL resource configuration and other parameters for data transmission, and the PSSCH can carry data transmission itself.

[0059] For PSSCH operations, the UE performs transmission or reception in a time slot on the carrier. Typically, transmission resources are reserved or allocated for sidelink transmissions on sub-channels within the frequency band for the time slot period. For the UE, NR sidelink supports a case where all symbols in a time slot are available for the sidelink, and another case where only a subset of consecutive symbols in a time slot are available for the sidelink.

[0060] In NR, there are generally two basic SL resource allocation modes. Figure 4A and Figure 4B Two modes of SL communication according to certain aspects of this disclosure are shown. According to the first mode (Mode 1), as... Figure 4A As shown, the BS can allocate resources for SL communication between UEs. According to the second mode (Mode 2), the UE autonomously selects SL resources (following some rules in the NR standard).

[0061] However, the signaling on the SL is identical for both resource allocation modes. Therefore, from the perspective of the receiving UE, there is no difference between the two modes. Resource allocation in Mode 1 and Mode 2 can share the resource pool.

[0062] In some systems, the TA can be used to control the timing of the UL signal in cellular UL transmission. Based on the TA, the UE can delay (e.g., transmit later) or advance the UL transmission (e.g., transmit earlier) by a certain amount relative to a reference timing.

[0063] For example, during a Random Access Channel (RACH) procedure, a network entity (e.g., a BS) can determine the TA to be applied in the UL transmission by measuring the propagation delay from the RACH signal. In LTE, when a UE wishes to establish a Radio Resource Control (RRC) connection with a network entity, the UE can send a random access preamble. Upon receiving the preamble, the network entity can estimate the terminal's transmission timing and send a random access response that may include a TA command. Based on the TA, the UE can adjust the terminal's transmission timing relative to the downlink timing.

[0064] Figure 5 An example relationship between LTE downlink (DL) timing and UL timing during the RACH process is shown, according to certain aspects of this disclosure. For example... Figure 5 As shown, a network entity (e.g., a BS) can send a DL frame i at time t0, which can be transmitted by a UE at time t0+t. pd Received at location t, where t pd This is the propagation delay from the network entity to the UE. Subsequently, the UE can send data with timing reference t0+t. pd RACH signals (e.g., such as) Figure 5The UL frame i shown can be generated by a network entity at time t0+2t. pd The network entity can determine the TA based on the propagation delay determined from the timing of the received RACH signal.

[0065] Typically, the TA determined by the network entity relative to the UE's DL reception time is approximately 2t. pd When the UE applies this TA to UL transmission (i.e., the UE advances the UL transmission by 2t relative to its DL timing), pd When ), the UE ensures that the arrival time of the UL signal at the network entity is aligned with the timing of the network entity's DL transmitter (TX).

[0066] Because the timing of arrival (TA) depends on the propagation delay from the network entity, different UEs can apply different TAs to their UL transmissions. This helps ensure that the arrival timing of UL signals from different UEs is aligned with the DL TX timing of the network entity.

[0067] Example timing advance (TA) determination for side link (SL) communication

[0068] This disclosure provides apparatus, methods, processing systems, and computer-readable media for determining timing advance (TA) used in side-link (SL) communications. For example, in some cases, a sending (TX) user equipment (UE) can determine at least one of a first TA or a second TA to be applied when transmitting at least a first SL transmission and at least a second SL transmission to a receiving (RX) UE, respectively.

[0069] In SL communication (e.g., vehicle-to-everything (V2X) or device-to-device (D2D)), two or more UEs can share uplink (UL) spectrum. For example, a resource pool in the UL spectrum (e.g., resource elements in a UL timeslot) can be configured for SL communication between two or more UEs.

[0070] As described above (refer to) Figure 4A and Figure 4BThere are typically two basic SL resource allocation modes (e.g., Mode 1 and Mode 2). In Mode 1, where SL communication sharing the UL spectrum is scheduled by the BS, the BS can allocate resources to the SL TX UE (e.g., via downlink control information (DCI)). The SL TX UE can then send downlink control information (SCI) and data to the SL RX UE within the allocated resources. The SL RX UE can detect the SCI and decode the data. In Mode 2, where the UE autonomously selects SL resources, the BS can instruct the SL TX UE to select resources from a resource pool configuration. Therefore, the SL TX UE can select resources from the pool and send SCI and data to the SL RX UE within the selected resources. The SL RX UE can detect the SCI and decode the data.

[0071] In some cases, TA can be applied to SL transmissions. For example, in SL mode 1 of LTE Release 12 and 13, the timing of SCI transmissions can be based on downlink (DL) timing, while the timing of data channel transmissions can be based on DL timing plus ULTA (where ULTA is based on UL timing). TA can be indicated in the SCI, and SL TX UEs or SL RX UEs can apply ULTA to transmit and receive, respectively. In SL mode 2 of LTE Release 12 and 13, as another example, TA may not be applied. In LTE Release 14 and 15, as another example, all transmission modes can be based on DL timing (or GNSS timing in V2X communication), and TA may not be applied. Additionally, in NR Release 16, all SL transmission modes can be based on DL timing, and TA may not be applied.

[0072] However, applying DL timing and / or UL timing in SL transmissions can lead to further problems. When DL timing is applied to SL transmissions, UL transmission interference may occur. For example, when SL and UL transmissions are multiplexed in the same time slot (e.g., Frequency Division Multiplexing (FDM)), misaligned RX timing of the two transmissions at the network entity (e.g., BS) can cause interference with the UL transmission. Alternatively, when UL timing is applied to SL transmissions, the RX UE may not be able to correctly decode the SL transmission. For example, when UL timing is applied to SL transmissions, the SL RX UE (and in some cases, such as the SL TX UE in Autonomous Mode 2) may not be aware of the timing used for the SL transmission (e.g., when the timing is based on the UL timing of the SL TX UE). If the timing used for the SL transmission is not DL timing and is unknown to the SL RX UE, the SL RX UE may not be able to correctly decode the SL transmission.

[0073] Therefore, this disclosure provides techniques for determining the TA used in SL communications.

[0074] Figure 6 Example operation 600 for wireless communication by a TX UE, according to certain aspects of this disclosure, is shown. For example, it can be performed by... Figure 1 or Figure 2 The UE 120 shown performs operation 600 when performing SL communication with another UE.

[0075] Operation 600 begins at 605, where the TX UE applies the first TA when sending at least the first SL transmission to the RX UE. At 610, the TX UE applies the second TA when sending at least the second SL transmission to the RX UE.

[0076] In some respects, the first SL transmission includes PSCCH, and the second SL transmission includes PSSCH.

[0077] In some aspects, the first SL transmission includes a first transmission of the first TB, and the second SL transmission includes at least one of a retransmission of the first TB or a transmission of the second TB.

[0078] Figure 7 An example operation 700 for wireless communication by an RX UE is shown, which can be considered as... Figure 6 Operation 600 is complementary. For example, operation 700 can be executed by the RX UE to execute from the execution Figure 6 Operation 600's TX UE receives an instruction regarding the second TA.

[0079] Operation 700 begins at 705, where the RX UE obtains an instruction regarding the TA from the TX UE during the first SL transmission. At 710, the RX UE applies this TA upon receiving at least a second SL transmission from the TX UE.

[0080] In this disclosure, the TX UE can determine at least one of a first TA or a second TA to be applied to the SL transmission. The TX UE can apply the first TA when sending at least a first SL transmission to the RX UE. The TX UE can apply the second TA when sending at least a second SL transmission to the RX UE.

[0081] In some aspects, the first SL transmission can be a control signaling transmission (e.g., the Physical Side Link Control Channel (PSCCH)) and the second SL transmission can be a data channel transmission (e.g., the Physical Side Link Shared Channel (PSSCH)). LTE Release 12D2D includes SL transmissions with similar definitions; however, the examples herein may include different design options.

[0082] In some respects, the first SL transmission may be the first transmission of a transport block (TB) (e.g., a new transmission of the first TB), and the second SL transmission may be a retransmission of the same TB (e.g., a retransmission of the first TB).

[0083] In some respects, the first SL transmission may be a transmission of the first transport block (TB) (e.g., a new transmission or retransmission of the first TB), and the second SL transmission may be a first transmission of another TB (e.g., a new transmission of the second TB).

[0084] In some respects, the first TA can be based on a predetermined value. If the SL communication between the TX UE and the RX UE shares a frequency division duplex (FDD) spectrum (e.g., an FDD UL band), the predetermined value can be zero. If the SL communication between the TX UE and the RX UE shares a time division duplex (TDD) spectrum (e.g., a TDD UL timeslot), the predetermined value can be a fixed value (e.g., the fixed value t specified in the 3GPP specification). TA,offset ).

[0085] In some aspects, the second TA can be based on the UL TA of the TX UE. In some aspects, the second TA can be based on the quantized UL TA of the TX UE. In some examples, the second TA can be based on the mapping of the UL TA.

[0086] In some aspects, the second TA can be based on an instruction received from a network entity (e.g., a BS). The TX UE can receive an instruction regarding the second TA via downlink control information (DCI). The network entity can indicate whether to apply a TA with a zero or non-zero value. The non-zero TA can be a predetermined value (e.g., fixed) or a TA based on the TX UE's UL TA.

[0087] In this disclosure, when the first SL transmission includes a PSCCH and the second SL transmission includes a PSSCH, the first SL transmission and the second SL transmission can be transmitted in the same time slot via Time Division Multiplexing (TDM). For example, the first SL transmission can be transmitted in the first set of Orthogonal Frequency Division Multiplexing (OFDM) symbols of the time slot. The second transmission can be transmitted in the second set of OFDM symbols of the same time slot. Furthermore, a gap may exist between the first SL transmission and the second SL transmission.

[0088] Figure 8A and Figure 8B The nominal timeslot format for SL data transmission (without TA application) and the actual timeslot format for SL data transmission (with TA application) according to certain aspects of this disclosure are shown respectively. Control channel (CCH) transmission and shared channel (SCH) (e.g., data channel) transmission can be time-division multiplexed (TDM) in the same timeslot. Figure 8A As shown, when the TX UE does not apply TA when sending SCH transmissions to the RX UE, there may be a nominal gap duration (e.g., t) between the CCH and SCH transmissions. gap In some examples, the nominal gap duration can be specified, pre-configured, or configured by the network entity. In some examples, the pre-configured nominal gap duration can be based at least in part on a set of predetermined gap durations.

[0089] Alternatively, such as Figure 8B As shown, when the TX UE applies a non-zero TA when sending SCH transmissions to the RX UE, there may be a small gap between the CCH and SCH (compared to the nominal gap t). gap (Compared to) When a non-zero TA is applied, data transmission is sent earlier, resulting in a shorter gap duration between the CCH and SCH compared to when no TA is transmitted to the SCH. The actual observed gap when an TA is transmitted to the SCH can be equal to t. gap -t TA -t TA,offset Therefore, as the applied TA value increases, the duration of the observed gap decreases.

[0090] Figure 9 This is an exemplary transmission timeline illustrating the application of TA in SL communication according to certain aspects of this disclosure. For example... Figure 9 As shown, at the beginning of a time slot or frame (e.g., t0), a network entity (e.g., BS) may send a DL frame i at time t0, which can be transmitted by the TX UE at time t0+t. pd It was observed at [location], where t pd This is the propagation delay from the network entity to the TX UE. Subsequently, the TX UE can send sidelink control information (SCI) to the RX UE in the sidelink control channel (e.g., PSCCH). The transmission of the SCI at t1 can be at least partially based on the observed DL timing (t1 = t0 + t). pd,TX The SL control channel can have t PSCCH The duration. Having a predetermined nominal duration (e.g., t). gap The gap between CCH and SCH transmissions can follow the control channel transmission. To reduce the duration of the gap between CCH and SCH transmissions, the TX UE can determine the TA (e.g., t) for the second SL transmission (e.g., SCH transmission in this example). TA Therefore, TX UE can be achieved at time t2 = t1 + t. PSCCH ++t gap -t TA -t TA,offset The data channel (e.g., SCH) is used to transmit data, where tPSCCH It is the duration of the SL CCH transmission, t gap It is the nominal gap duration, t TA It is the second TA transmitted to the second SL, and t TA,offset It is the first TA (if any) of the application transmitted to the first SL.

[0091] Nominal gap duration t gap It can be equal to or greater than t TA +t TA,offset This makes the actual gap between CCH and SCH transmissions greater than zero (e.g., t). gap -(t TA +t TA,offset ≥0). As mentioned above, the nominal gap duration (e.g., t) gap This can be specified, pre-configured, or configured by the network entity (for example, the network entity can configure a value based on the cell radius).

[0092] In some aspects, the first SL transmission may include a first (e.g., initial) transmission of the first TB, and the second SL transmission may include a retransmission of the first TB or a first transmission of the second TB. Therefore, the TX UE may reserve future resources for the transmission of the second SL transmission, so that the second SL transmission can be sent in the reserved future resources and be applied with the second TA.

[0093] Figure 10 This is an exemplary transmission timeline illustrating the transmission and resource reservation of an SL device according to aspects of this disclosure. For example... Figure 10 As shown in the exemplary transmission timeline, the UE (e.g., as an SL device) is... Figure 1 The UE 120a) shown can transmit SL transmissions during time slot 1002 on sub-channels 1024 and 1026. Control information included in the SL transmission can be reserved in transmission resources on sub-channels 1022 and 1024 during time slot 1008. Control information in the SL transmission can also be reserved in transmission resources on sub-channels 1020 and 1022 during time slot 1016. Transmission resources can be reserved for SL transmissions or for retransmission of data in another TB of transmission.

[0094] For reference Figure 9 As described, the TX UE can send the first SL transmission based on DL timing (e.g., DL timing observed by the TX UE). In other words, the first TA for the first SL transmission can be based on the DL timing used for transmissions between the network entity and the TX UE. In some examples, the first TA can be zero (e.g., no TA is applied). In some examples, the first TA can be equal to t. TA,offset .

[0095] Subsequently, when the TX UE sends a second SL transmission in the reserved resources, the TX UE can apply a second TA. For example, the TX UE can apply TA=t TA +t TA,offset Sending is performed within the reserved resources, where t TA It is the second TA transmitted to the second SL, and t TA,offset This is the first TA (if any) for transmitting the application to the first SL. In some examples, the second TAt... TA It can be based on the UL timing used for transmission between the network entity and the TX UE. In some examples, the first TA(t) TA,offset It can be based on a predetermined value (e.g., zero or a fixed value).

[0096] In some aspects, the TX UE may indicate in the first SL transmission to the RX UE the TA value to be applied when receiving at least the second SL transmission (e.g., the second TA or t). TA The indicated TA can allow the RX UE receiving the first SL transmission to determine the correct reception timing for at least the second SL transmission from the TX UE. In some examples, the first SL transmission indicating the second TA may be an SCI (e.g., a second-stage SCI).

[0097] In some aspects, resource reservation can be chained. Chained resource reservation can include reserving resources for the (n+1)th transmission in the nth transmission. According to certain aspects of this disclosure, in each transmission, up to the nth transmission, a TA can be indicated to the RX UE. The RX UE can apply the TA indicated in the current SL transmission to the next SL transmission from the TX UE to the RX UE.

[0098] In some aspects, the RX UE may miss the first SL transmission from the TX UE. Therefore, the RX UE can resume receiving the second SL transmission based on the implementation.

[0099] Figure 11 The diagram illustrates operations that may include those configured to perform the techniques disclosed herein (e.g., Figure 6 The communication device 1100 comprises various components (e.g., corresponding to functional module unit components) of the operation shown herein. The communication device 1100 includes a processing system 1102 coupled to a transceiver 1108. The transceiver 1108 is configured to transmit and receive signals for the communication device 1100 via an antenna 1110, such as the various signals described herein. The processing system 1102 may be configured to perform processing functions for the communication device 1100, including processing signals received by and / or to be transmitted by the communication device 1100.

[0100] Processing system 1102 includes processor 1104 coupled to computer-readable medium / memory 1112 via bus 1106. In some aspects, computer-readable medium / memory 1112 is configured to store instructions (e.g., computer-executable code) that, when executed by processor 1104, cause processor 1104 to perform. Figure 6 The operations shown, or other operations for performing the various techniques discussed herein. In some aspects, the computer-readable medium / memory 1112 stores code 1114 for application (e.g., for applying a first TA when transmitting at least a first SL transmission to the RX UE) and code 1116 for application (e.g., for applying a second TA when transmitting at least a second SL transmission to the RX UE). In some aspects, the processor 1004 has circuitry configured to implement the code stored in the computer-readable medium / memory 1112. The processor 1104 includes circuitry 1124 for application (e.g., for applying a first TA when transmitting at least a first SL transmission to the RX UE) and circuitry 1126 for application (e.g., for applying a second TA when transmitting at least a second SL transmission to the RX UE).

[0101] Figure 12 The diagram illustrates operations that may include those configured to perform the techniques disclosed herein (e.g., Figure 7 The communication device 1200 comprises various components (e.g., corresponding to functional module unit components) shown in the diagram. The communication device 1200 includes a processing system 1202 coupled to a transceiver 1208. The transceiver 1208 is configured to transmit and receive signals for the communication device 1200 via an antenna 1210, such as the various signals described herein. The processing system 1202 may be configured to perform processing functions for the communication device 1200, including processing signals received by and / or to be transmitted by the communication device 1200.

[0102] Processing system 1202 includes processor 1204 coupled to computer-readable medium / memory 1212 via bus 1206. In some aspects, computer-readable medium / memory 1212 is configured to store instructions (e.g., computer-executable code) that, when executed by processor 1204, cause processor 1204 to perform. Figure 7The operations shown, or other operations for performing the various techniques discussed herein. In some aspects, the computer-readable medium / memory 1212 stores code 1214 for obtaining (e.g., for obtaining an instruction about the TA from the TX UE in a first SL transmission) and code 1216 for applying (e.g., for applying the TA when receiving at least a second SL transmission from the TX UE). In some aspects, the processor 1204 has circuitry configured to implement the code stored in the computer-readable medium / memory 1212. The processor 1204 includes circuitry 1224 for obtaining (e.g., for obtaining an instruction about the TA from the TX UE in a first SL transmission) and circuitry 1226 for applying (e.g., for applying the TA when receiving at least a second SL transmission from the TX UE).

[0103] Example

[0104] In addition to the various aspects described above, specific combinations of aspects fall within the scope of this disclosure, some of which are as follows:

[0105] Aspect 1: A method for wireless communication by a transmitting (TX) user equipment (UE), comprising: applying a first timing advance (TA) when transmitting at least a first side-link (SL) transmission to a receiving (RX) UE; and applying a second TA when transmitting at least a second SL transmission to the RX UE.

[0106] Aspect 2: According to the method of aspect 1, wherein: the first SL transmission includes a physical side link control channel (PSCCH); and the second SL transmission includes a physical side link sharing channel (PSSCH).

[0107] Aspect 3: The method according to any one of Aspects 1-2, wherein the first SL transmission and the second SL transmission are transmitted in the same time slot via Time Division Multiplexing (TDM).

[0108] Aspect 4: The method according to any one of Aspects 1-3, wherein the first TA is based on downlink (DL) timing for transmission between the network entity and the TX UE.

[0109] Aspect 5: The method according to any one of Aspects 1-4 further includes: determining the second TA based on the nominal gap duration between the end of the first SL transmission and the start of the second SL transmission.

[0110] Aspect 6: According to the method of aspect 5, wherein the nominal gap duration is specified, pre-configured, or configured by the network entity.

[0111] Aspect 7: The method according to aspect 5, wherein the pre-configured nominal gap duration is at least partially based on a set of predetermined gap durations.

[0112] Aspect 8: The method according to any one of Aspects 1-7, wherein: the first SL transmission includes a first transmission of a first transport block (TB); and the second SL transmission includes at least one of a retransmission of the first TB or a transmission of the second TB.

[0113] Aspect 9: The method according to aspect 8 further includes: reserving future resources for the transmission of the second SL transmission, wherein the second SL transmission is transmitted in the reserved future resources and is subject to at least one of the first TA or the second TA.

[0114] Aspect 10: The method according to any one of Aspects 1-9, wherein the first TA is based on downlink (DL) timing for transmission between the network entity and the TX UE.

[0115] Aspect 11: The method according to aspect 10, wherein the first TA is at least one of the following: a zero value; or an offset value based on DL timing.

[0116] Aspect 12: The method according to any one of Aspects 1-11, wherein the second TA is based on uplink (UL) timing for transmission between the network entity and the TX UE.

[0117] Aspect 13: The method according to any one of aspects 1-12 further includes: indicating the second TA in the first SL transmission to the RX UE.

[0118] Aspect 14: The method according to aspect 13, wherein the indication is indicated in side link control information (SCI).

[0119] Aspect 15: The method according to any one of Aspects 1-14, wherein the first TA is based on a predetermined value.

[0120] Aspect 16: The method according to aspect 15, wherein: if the SL communication between the TX UE and the RX UE shares a frequency division duplex (FDD) spectrum, the predetermined value is zero; and if the SL communication between the TX UE and the RX UE shares a time division duplex (TDD) spectrum, the predetermined value is a fixed value.

[0121] Aspect 17: The method according to any one of Aspects 1-16, wherein the second TA is based on at least one of the following: the uplink (UL) TA of the TX UE; or the quantized UL TA of the TX UE.

[0122] Aspect 18: The method according to aspect 17 further includes: receiving an indication from a network entity regarding the second TA via downlink control information (DCI).

[0123] Aspect 19: The method according to aspect 18, wherein the indicated second TA is based on at least one of the following: a zero value; a predetermined non-zero value; or the UL TA.

[0124] Aspect 20: A method for wireless communication by a receiving (RX) user equipment (UE), comprising: obtaining an indication of timing advance (TA) from a transmitting (TX) UE during a first side line link (SL) transmission; and applying the TA when receiving at least a second SL transmission from the TX UE.

[0125] Aspect 21: The method according to aspect 20, wherein: the first SL transmission includes a first transmission of a first transport block (TB); and the second SL transmission includes at least one of a retransmission of the first TB or a transmission of the second TB.

[0126] Aspect 22: The method according to any one of Aspects 20-21, wherein the first SL transmission includes side link control information (SCI).

[0127] Aspect 23: The method according to any one of Aspects 20-22, wherein the indicated TA is based on at least one of the following: a zero value; a predetermined non-zero value; or the UL TA.

[0128] Aspect 24: A transmitting (TX) user equipment (UE) comprising: at least one antenna; and a processing system configured to: apply a first timing advance (TA) when transmitting at least a first side link (SL) transmission to a receiving (RX) UE via the at least one antenna, and apply a second TA when transmitting at least a second SL transmission to the RX UE via the at least one antenna.

[0129] Aspect 25: A receiving (RX) user equipment (UE) comprising: a receiver configured to receive an indication of timing advance (TA) from a sending (TX) UE during a first side link (SL) transmission; and a processing system configured to apply the TA when receiving at least a second SL transmission from the TX UE.

[0130] Aspect 26: A transmitting (TX) user equipment (UE) comprising: a unit for providing at least one antenna; a unit for applying a first timing advance (TA) when transmitting at least a first side link (SL) transmission to a receiving (RX) UE via the at least one antenna; and a unit for applying a second TA when transmitting at least a second SL transmission to the RX UE via the at least one antenna.

[0131] Aspect 27: A receiver (RX) user equipment (UE) comprising: a unit for receiving an indication of timing advance (TA) from a sender (TX) UE during a first side link (SL) transmission; and a unit for applying the TA when receiving at least a second SL transmission from the TX UE.

[0132] Aspect 28: A computer-readable medium for wireless communication by a transmitting (TX) user equipment (UE), comprising code capable of performing the following operations: applying a first timing advance (TA) when transmitting at least a first side-link (SL) transmission to a receiving (RX) UE; and applying a second TA when transmitting at least a second SL transmission to the RX UE.

[0133] Aspect 29: A computer-readable medium for wireless communication by a receiving (RX) user equipment (UE), comprising code capable of performing the following operations: obtaining an indication of timing advance (TA) from a sending (TX) UE during a first side line link (SL) transmission; and applying the TA when receiving at least a second SL transmission from the TX UE.

[0134] Aspect 30: An apparatus for wireless communication by a transmitting (TX) user equipment (UE), comprising: a processing system configured to apply a first timing advance (TA) when transmitting at least a first side link (SL) transmission to a receiving (RX) UE, and to apply a second TA when transmitting at least a second SL transmission to the RX UE.

[0135] Aspect 31: An apparatus for wireless communication by a receiving (RX) user equipment (UE), comprising: an interface configured to obtain an indication of timing advance (TA) from a transmitting (TX) UE during a first side link (SL) transmission; and a processing system configured to apply the TA when receiving at least a second SL transmission from the TX UE.

[0136] Other precautions

[0137] The methods disclosed herein include one or more steps or actions for implementing these methods. The method steps and / or actions may be interchanged without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0138] As used herein, the phrase “at least one of the items” refers to any combination of those items, including single members. For example, “at least one of a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbb, cc, and ccc, or any other order of a, b, and c).

[0139] As used herein, the term "determine" encompasses a wide variety of actions. For example, "determine" can include calculation, operation, processing, derivation, investigation, searching (e.g., searching in a table, database, or other data structure), and confirmation. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and parsing, selecting, choosing, and creating.

[0140] The preceding description is provided to enable those skilled in the art to implement the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the few aspects shown herein, but rather to the full scope consistent with the language of the claims, wherein, unless specifically stated otherwise, reference to a singular element is not intended to mean “one and only one,” but rather “one or more.” Unless otherwise specifically stated, the term “some” means one or more. All structural and functional equivalents of elements throughout the various aspects described in this disclosure that are known or will be known hereafter by those skilled in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is expressly recited in the claims. No claim shall be construed in accordance with 35 U.SC. No claim element shall be construed in accordance with the provisions of 35 U.SC §112(f) unless the element is expressly stated using the phrase “module for…” or, in the case of a method claim, the element is expressly stated using the phrase “step for…”.

[0141] The various operations described above can be performed by any suitable unit capable of performing the corresponding functions. The unit may include various hardware and / or software components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors. Typically, in the cases of the operations shown in the figures, those operations may have corresponding functional module components with similar numbering. For example, Figure 2 The processors 258, 264, and 266 of the UE 120a, and / or the controller / processor 280, and / or the processors 220, 230, 238, and / or the controller / processor 240 of the BS110a, can be configured to perform Figure 6 Operation 600 and / or Figure 7 Operation 700.

[0142] The unit for receiving may include Figure 2 The transceiver, receiver, or at least one antenna and at least one receiver processor are shown. The unit for transmitting, the unit for sending, or the unit for outputting may include... Figure 2 The transceiver, transmitter, or at least one antenna and at least one transmit processor are shown. The units for application, determination, reservation, and indication may include a processing system, which may include one or more processors, for example, Figure 2 The processors 258, 264, and 266 of the UE 120a shown, and / or the controller / processor 280, and / or the processors 220, 230, 238, and / or the controller / processor 240 of the BS110a.

[0143] In some cases, a device may have an interface (a unit for outputting frames for transmission) for transmitting, rather than actually sending frames. For example, a processor may output frames to a radio frequency (RF) front-end for transmission via a bus interface. Similarly, a device may have an interface for receiving frames from another device (a unit for receiving), rather than actually receiving frames. For example, a processor may receive (or acquire) frames from an RF front-end for receiving via a bus interface.

[0144] The various operations described above can be performed by any suitable unit capable of performing the corresponding function. This unit may include various hardware and / or software components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors. Generally, in the presence of the operations shown in the accompanying drawings, these operations may have corresponding functional module unit components. For example, they may be performed by… Figure 2 The various processors shown execute Figure 6 and / or Figure 7 The various operations shown.

[0145] The various illustrative logic blocks, modules, and circuits described in connection with this disclosure may be implemented or executed using a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but optionally, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors incorporating a DSP core, or any other such configuration.

[0146] If implemented in hardware, an exemplary hardware configuration may include a processing system in a wireless node. The processing system can be implemented using a bus architecture. The bus may include any number of interconnect buses and bridges, depending on the specific application and overall design constraints of the processing system. The bus can link various circuits together, including processors, machine-readable media, and bus interfaces. The bus interface can be used to connect network adapters, etc., to the processing system via the bus. The network adapter can be used to implement signal processing functions at the PHY layer. In the case of user terminal 120 (see...), Figure 1 The user interface (e.g., keyboard, display, mouse, joystick, etc.) can also be connected to the bus. The bus can also link various other circuits, such as timing sources, peripheral devices, voltage regulators, power management circuits, etc., which are well known in the art and will not be described further. The processor can be implemented using one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits capable of executing software. Those skilled in the art will recognize how the described functions for the processing system can be optimally implemented, depending on the specific application and the overall design constraints imposed on the system.

[0147] If implemented in software, these functions can be stored or transmitted as one or more instructions or code via a computer-readable medium. Software should be interpreted broadly as representing instructions, data, or any combination thereof, whether it refers to software, firmware, middleware, microcode, hardware description languages, or others. Computer-readable media includes computer storage media and communication media, including any medium that facilitates the transfer of computer programs from one place to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on the machine-readable storage medium. The computer-readable storage medium may be coupled to the processor, allowing the processor to read information from and write information to the storage medium. Alternatively, the storage medium may be an integral part of the processor. As an example, machine-readable media may include transmission lines, carrier waves modulated by data, and / or computer-readable storage media on which instructions separate from the wireless node are stored, all accessible to the processor via a bus interface. Alternatively or additionally, the machine-readable medium or any portion thereof may be integrated into the processor, for example, in cases where there may be caches and / or general-purpose register files. As an example, machine-readable storage media may include, for example, RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, disks, optical disks, hard disks, or any other suitable storage media, or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0148] Software modules can comprise a single instruction or a number of instructions, and can be distributed across several different code segments, different programs, and multiple storage media. Computer-readable media can include multiple software modules. Software modules include instructions that, when executed by a device such as a processor, cause the processing system to perform various functions. Software modules can include send modules and receive modules. Each software module can reside in a single storage device or be distributed across multiple storage devices. For example, when a trigger event occurs, a software module can be loaded from a hard disk drive into RAM. During the execution of a software module, the processor can load some instructions into a cache to improve access speed. One or more caches can then be loaded into a general-purpose register file for processor execution. When referring to the functionality of the software module below, it should be understood that these functions are implemented by the processor when instructions are executed from that software module.

[0149] Furthermore, any connection is appropriately referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, then the definition of media includes coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave. Disks and optical discs as used herein include compact optical discs (CDs), laser discs, optical discs, digital versatile optical discs (DVDs), floppy disks, and... Optical discs, where magnetic disks typically reproduce data magnetically, and optical discs reproduce data optically using lasers. Therefore, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Furthermore, in other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0150] Therefore, certain aspects may include a computer program product for performing the operations described herein. For example, such a computer program product may include a computer-readable medium having instructions stored (and / or encoded thereon) thereon, which can be executed by one or more processors to perform the operations described herein. For example, the instructions are used to perform the operations described herein and Figure 6 and / or Figure 7 The operation is shown in the figure.

[0151] Furthermore, it should be understood that modules and / or other suitable units for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by the user terminal and / or base station as appropriate. For example, such a device may be coupled to a server to facilitate the transmission of units for performing the methods described herein. Alternatively, the various methods described herein may be provided via storage devices (e.g., RAM, ROM, physical storage media such as compressed optical discs (CDs) or floppy disks), enabling the user terminal and / or base station to obtain the various methods when the storage units are coupled to or provided to the device. Furthermore, any other suitable techniques for providing the methods and techniques described herein to the device may be used.

[0152] It should be understood that the claims are not limited to the precise configurations and components described above. Various modifications, alterations, and variations may be made to the arrangement, operation, and details of the above-described methods and apparatus without departing from the scope of the claims.

Claims

1. A method of wireless communication by a transmitter (TX) user equipment (UE), comprising: applying a first timing advance (TA) when transmitting at least a first sidelink (SL) transmission to a receiver (RX) UE, wherein the first SL transmission comprises a first transmission of a first transport block (TB); and applying a second TA when transmitting at least a second SL transmission to the RX UE, wherein: the second SL transmission comprises a retransmission of the first TB or a transmission of a second TB; and a gap duration between an end of the first SL transmission and a start of the second SL transmission is determined based on a nominal gap duration and the first TA.

2. The method of claim 1, wherein, the gap duration is further determined based on the second TA.

3. The method of claim 1, wherein: the first SL transmission comprises a physical sidelink control channel (PSCCH); and the second SL transmission comprises a physical sidelink shared channel (PSSCH).

4. The method of claim 1, wherein, the first SL transmission and the second SL transmission are transmitted in a same slot via time division multiplexing (TDM).

5. The method of claim 1, wherein, the nominal gap duration is specified by a network entity, preconfigured, or configured based on a cell radius.

6. The method of claim 5, wherein, the preconfigured nominal gap duration is based at least in part on a set of predetermined gap durations.

7. The method of claim 1, further comprising: reserving a future resource for a transmission of the second SL transmission, wherein the second SL transmission is transmitted in the future resource and at least one of the first TA or the second TA is applied.

8. The method of claim 1, wherein: the first TA is based on a downlink (DL) timing for transmissions between a network entity and the TX UE.

9. The method of claim 8, wherein, the first TA is at least one of: a zero value; or an offset value based on the DL timing.

10. The method of claim 1, wherein: the second TA is based on an uplink (UL) timing for transmissions between a network entity and the TX UE.

11. The method of claim 1, further comprising: indicating the second TA in the first SL transmission to the RX UE.

12. The method of claim 11, wherein, the indication is indicated in sidelink control information (SCI).

13. The method of claim 1, wherein, the first TA is based on a predetermined value.

14. The method of claim 13, wherein: the predetermined value is zero if SL communications between the TX UE and the RX UE share a frequency division duplex (FDD) spectrum; and the predetermined value is a fixed value if SL communications between the TX UE and the RX UE share a time division duplex (TDD) spectrum.

15. The method of claim 1, wherein, the second TA is based on at least one of: an uplink (UL) TA of the TX UE; or a quantized UL TA of the TX UE.

16. The method of claim 15, further comprising: receiving an indication of the second TA from a network entity via downlink control information (DCI).

17. The method of claim 16, wherein, a second TA indicated by the TX UE.

18. A method of wireless communication by a receiver (RX) user equipment (UE), comprising: obtaining, from a transmitter (TX) UE, an indication of a second timing advance (TA) in a first sidelink (SL) transmission, wherein the first SL transmission comprises a first transmission of a first transport block (TB), and wherein the first SL transmission is applied with a first TA by the TX UE; and applying the second TA when receiving at least a second SL transmission from the TX UE, wherein: the second SL transmission comprises a retransmission of the first TB or a transmission of a second TB; and a gap duration between an end of the first SL transmission and a start of the second SL transmission is determined based on a nominal gap duration and the first TA. the gap duration is further determined based on the second TA. the first SL transmission comprises sidelink control information (SCI). the second TA is based on at least one of:

19. The method of claim 18, wherein, a zero value; 20. The method of claim 18, wherein, a predetermined non-zero value; or 21. The method of claim 18, wherein, an UL TA.

22. A user equipment (UE) configured for wireless communication, comprising: a memory including processor-executable instructions; and a processor configured to execute the processor-executable instructions and cause the UE to perform the method of any of claims 1-17.

23. A user equipment (UE) configured for wireless communication, comprising: a memory including processor-executable instructions; and a processor configured to execute the processor-executable instructions and cause the UE to perform the method of any of claims 18-21. ​ ​ ​

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