Side Link Communication Recovery

Abstract

Certain aspects of the present disclosure provide techniques for restoring sidelink communications. A wireless node may receive a plurality of sidelink communications, each sidelink communication being between two user equipments (UEs); and transmit restoration information in a restoration time slot, where the restoration information is for restoring at least one of the sidelink communications of the two UEs or other UEs transmitted when at least one of the sidelink communications occurred, and where the restoration time slot is for the transmission of the restoration information.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Application No. 17 / 202,840, filed on March 16, 2021, which claims the benefit and priority of U.S. Provisional Application No. 62 / 992,984, filed on March 21, 2020. Both of these applications are hereby incorporated by reference in their entirety for all applicable purposes as if fully set forth herein below.

[0003] Background

[0004] Public domain

[0005] Aspects of the present disclosure relate to wireless communication, and more particularly to techniques for recovering sidelink communications missed by a wireless node due to the wireless node transmitting while sidelink communication is occurring.

[0006] Description of related technologies

[0007] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasting, etc. These wireless communication systems may employ multiple - access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple - access systems include Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE - Advanced (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 examples.

[0008] In some examples, a wireless multi-access communication system can include several base stations (BSs), each capable of supporting communications for multiple communication devices (also referred to as user equipment (UE)) simultaneously. In an LTE or LTE-A network, a set that includes one or more base stations can define an evolved Node B (eNB). In other examples (e.g., in a next-generation, new radio (NR), or 5G network), a wireless multi-access communication system can include several distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmission reception points (TRPs), etc.) in communication with several central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set that includes one or more DUs in communication with a CU can define an access node (e.g., it can be referred to as a BS, 5G NB, next-generation Node B (gNB or gNodeB), transmission reception point (TRP), etc.). The BS or DU can communicate with a set of UEs on a downlink channel (e.g., for transmission from the BS or DU to the UE) and an uplink channel (e.g., for transmission from the UE to the BS or DU).

[0009] These multi-access techniques have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the city, national, regional, and even global levels. NR (e.g., new radio or 5G) is an example of an emerging telecommunication standard. NR is an enhanced set of the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by using OFDMA with cyclic prefix (CP) on the downlink (DL) and uplink (UL) to improve spectral efficiency, reduce costs, improve services, utilize new spectrums, and better integrate with other open standards. To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0010] Sidelink communication is communication from one UE to another UE. As the demand for mobile broadband access continues to grow, there is a need for further improvements in NR and LTE technologies, including improvements to sidelink communication. Preferably, these improvements should be applicable to other multi-access techniques and telecommunication standards that employ these techniques.

[0011] Overview

[0012] The systems, methods, and devices of the present disclosure each have several aspects, and no single aspect alone is responsible for their desirable attributes. Without limiting the scope of the present disclosure as set forth in the appended claims, some features will now be briefly discussed. After considering this discussion and particularly after reading the section entitled "Detailed Description," it will be understood how the features of the present disclosure provide advantages including desirable wireless performance from sidelink communication such as desirable data rate, latency, and / or reliability.

[0013] Certain aspects provide a method for wireless communication by a wireless node. The method generally receives a plurality of sidelink communications, each sidelink communication being between two user equipments (UEs); and transmits recovery information in a recovery time slot, where the recovery information is for recovering at least one of the sidelink communications of the two UEs or other UEs transmitted when at least one of the sidelink communications occurs, and where the recovery time slot is for transmission of at least the recovery information.

[0014] Certain aspects provide a method for wireless communication by a first UE. The method generally includes: communicating a sidelink communication with a second UE; receiving recovery information in a recovery time slot, where the recovery information is for recovering at least one of the sidelink communications of one or more third UEs transmitted when the sidelink communication occurs, and where the recovery time slot is for transmission of the recovery information; and determining another sidelink communication transmitted by the wireless node based on the sidelink communication and the recovery information.

[0015] Certain aspects provide an apparatus for wireless communication. The apparatus generally includes a receiver configured to receive a plurality of sidelink communications, each of the sidelink communications being between two UEs. The apparatus further includes a transmitter configured to transmit recovery information in a recovery time slot, where the recovery information is for recovering at least one of the sidelink communications of the two UEs or other UEs transmitted when at least one of the sidelink communications occurs, and where the recovery time slot is for transmission of at least the recovery information.

[0016] Certain aspects provide an apparatus for wireless communication. The apparatus generally includes a transceiver, a memory, and a processor. The transceiver is configured to communicate a sidelink communication with a first UE; and receive recovery information in a recovery time slot, where the recovery information is for recovering at least one sidelink communication of one or more second UEs transmitted when the sidelink communication occurs, and where the recovery time slot is for transmission of the recovery information. The processor is coupled to the memory, and the processor and the memory are configured to determine another sidelink communication transmitted by the wireless node based on the sidelink communication and the recovery information.

[0017] Some aspects provide an apparatus for wireless communication. The apparatus generally includes: means for receiving a plurality of sidelink communications, each sidelink communication between two UEs; and means for transmitting recovery information in a recovery time slot, wherein the recovery information is for recovering at least one of the sidelink communications of the two UEs or other UEs transmitted when at least one of the sidelink communications occurs, and wherein the recovery time slot is for the transmission of at least the recovery information.

[0018] Some aspects provide an apparatus for wireless communication. The apparatus generally includes: means for communicating a sidelink communication with a first UE; means for receiving recovery information in a recovery time slot, wherein the recovery information is for recovering at least one of the sidelink communications of one or more second UEs transmitted when the sidelink communication occurs, and wherein the recovery time slot is for the transmission of the recovery information; and means for determining, based on the sidelink communication and the recovery information, another sidelink communication to be transmitted by a wireless node.

[0019] Some aspects provide a computer-readable medium for wireless communication by a wireless node. The computer-readable medium includes instructions that, when executed by a processing system, cause the processing system to perform operations that generally include: receiving a plurality of sidelink communications, each sidelink communication between two UEs; and transmitting recovery information in a recovery time slot, wherein the recovery information is for recovering at least one of the sidelink communications of the two UEs or other UEs transmitted when at least one of the sidelink communications occurs, and wherein the recovery time slot is for the transmission of at least the recovery information.

[0020] Some aspects provide a computer-readable medium for wireless communication by a wireless node. The computer-readable medium includes instructions that, when executed by a processing system, cause the processing system to perform operations that generally include: communicating a sidelink communication with a first UE; receiving recovery information in a recovery time slot, wherein the recovery information is for at least one of the sidelink communications of one or more second UEs transmitted when the sidelink communication occurs, and wherein the recovery time slot is for the transmission of the recovery information; and determining, based on the sidelink communication and the recovery information, another sidelink communication to be transmitted by a wireless node.

[0021] To achieve the foregoing and related purposes, one or more of these aspects include the features hereinafter fully described and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of one or more of these aspects. However, these features are merely indicative of the various ways in which the principles of the various aspects may be employed. Brief Description of the Drawings

[0023] To understand the manner in which the above-recited features of the present disclosure can be obtained, reference may be made to the aspects described in more detail below, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only certain typical aspects of the present disclosure and are not to be considered limiting of its scope, as the description may admit of other equally effective aspects.

[0024] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure.

[0025] Figure 2 is a block diagram illustrating an example logical architecture of a distributed radio access network (RAN) in accordance with certain aspects of the present disclosure.

[0026] Figure 3 is a diagram illustrating an example physical architecture of a distributed RAN in accordance with certain aspects of the present disclosure.

[0027] Figure 4 is a block diagram conceptually illustrating the design of an example base station (BS) and user equipment (UE) in accordance with certain aspects of the present disclosure.

[0028] Figure 5A and 5B show a graphical representation of an example vehicle-to-everything (V2X) system in accordance with some aspects of the present disclosure.

[0029] Figure 6 is an example transmission timeline of a sidelink in accordance with certain aspects of the present disclosure.

[0030] Figure 7 is an example transmission timeline illustrating sidelink resource reservation according to prior art.

[0031] Figure 8 is a flowchart illustrating example operations that may be performed by a wireless node in accordance with certain aspects of the present disclosure.

[0032] Figure 9 is a flowchart illustrating example operations that may be performed by a UE in accordance with certain aspects of the present disclosure.

[0033] Figure 10 is a signaling flow diagram illustrating an example signal flow for restoring sidelink communication in accordance with various aspects of the present disclosure.

[0034] Figure 11 is an example transmission timeline of a sidelink communication with a transmission having recovery information in accordance with certain aspects of the present disclosure.

[0035] Figure 12A and 12Bis an exemplary transmission timeline for sidelink communication that illustrates transmission of recovery information for a first-phase sidelink control information (SCI-1) in accordance with certain aspects of the present disclosure.

[0036] Figure 13 is an exemplary transmission timeline for sidelink communication that illustrates transport block (TB) bundling for generating recovery information in accordance with certain aspects of the present disclosure.

[0037] Figure 14 is an exemplary transmission timeline for sidelink communication that illustrates repetition of some slot transmissions in accordance with certain aspects of the present disclosure.

[0038] Figure 15 illustrates a communication device (e.g., a wireless node) that may include various components configured to perform Figure 8 the illustrated operations in accordance with certain aspects of the present disclosure.

[0039] Figure 16 illustrates a communication device (e.g., a UE) that may include various components configured to perform Figure 9 the illustrated operations in accordance with certain aspects of the present disclosure.

[0040] For the sake of facilitating understanding, where possible, the same reference numerals have been used to designate identical elements common to the various figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation.

[0041] Detailed Description

[0042] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for recovering sidelink communication missed by a wireless node due to the wireless node transmitting while the sidelink communication is occurring. When a UE transmits sidelink communication in a frequency band, the UE typically cannot receive another communication in the same frequency band (e.g., another sidelink communication from another UE). In aspects of the present disclosure, a wireless node may receive the sidelink communication and transmit recovery information in a recovery time slot. A UE that is transmitting during a period (e.g., a time slot) of the sidelink communication may receive the recovery information and recover the sidelink communication that the UE missed while the UE was transmitting (e.g., determine the content of the sidelink communication). In some aspects of the present disclosure, the wireless node may generate parity information as recovery information that the UE may use to recover the sidelink communication. In some aspects of the present disclosure, the wireless node may transmit a repetition of the sidelink communication as recovery information. The techniques described herein for recovering sidelink communication may achieve desired wireless performance from the sidelink communication, such as a desired data rate, latency, and / or reliability.

[0043] The following description provides examples and is not intended to 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 the disclosure. Various examples may appropriately omit, substitute, or add various procedures or components. For example, the methods described may be performed in a different order than described, and various steps may be added, omitted, or combined. Also, features described with reference to some examples may be combined in some other examples. For instance, any number of the aspects set forth herein may be used to implement a device or practice a method. Additionally, the scope of the disclosure is intended to cover such devices or methods practiced using other structures, functionality, or a combination of structures and functionality that supplement or are different from the aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be implemented by one or more elements of the claims. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" need not be construed as superior to or better than other aspects.

[0044] The techniques described herein can be used for various wireless communication technologies such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other networks. The terms "network" and "system" are often used interchangeably. CDMA networks may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. Cdma2000 covers the IS-2000, IS-95, and IS-856 standards. TDMA networks may implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks may 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, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS).

[0045] New Radio (NR) is an emerging wireless communication technology being developed in cooperation with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are UMTS releases that use 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 techniques described herein can be used in the wireless networks and radio technologies mentioned above and in other wireless networks and radio technologies. For clarity, while aspects may be described herein using terms typically associated with 3G and / or 4G wireless technologies, aspects of the present disclosure can be applied in communication systems based on other generations, including NR technology, such as 5G and later generations.

[0046] New Radio (NR) access (e.g., 5G technology) can support various wireless communication services, such as enhanced mobile broadband (eMBB) targeted at wide bandwidths (e.g., 80 MHz or higher), millimeter wave (mmW) targeted at high carrier frequencies (e.g., 25 GHz or higher), massive machine type communication MTC (mMTC) targeted at non-backward compatible MTC technology, and / or mission critical targeted at 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 the corresponding quality of service (QoS) requirements. Additionally, these services can coexist in the same subframe.

[0047] Figure 1 An example wireless communication network 100 is illustrated in which aspects of the present disclosure can be implemented. For example, Figure 1 UE120a and / or BS 110a of Figures 8-9 can be configured to perform the operations described below with reference to

[0048] to recover, for example, sidelink communications that are received in error or missed by a wireless node due to the wireless node transmitting while sidelink communication is occurring. Figure 1As explained, the wireless communication network 100 may include several base stations (BSs) 110a-z (each also individually referred to herein as BS 110 or collectively as BS 110) and other network entities. In aspects of the present disclosure, a roadside service unit (RSU) may be considered a type of BS, and BS 110 may be referred to as an RSU. BS 110 may provide communication coverage for a particular geographic area (sometimes referred to as a "cell"), which may be stationary or may move depending on the location of the mobile BS 110. In some examples, BS 110s may be interconnected with each other and / or with one or more other BSs or network nodes (not shown) in the wireless communication network 100 using any suitable transport network via various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.). In Figure 1 In the example shown, BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells. BS 110 communicates with user equipment (UEs) 120a-y (each also individually referred to herein as UE 120 or collectively as UEs 120) in the wireless communication network 100. UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile.

[0049] According to certain aspects, BS 110 and UE 120 may be configured to recover sidelink communications that are received in error or missed by a wireless node, e.g., due to the wireless node transmitting while sidelink communication is occurring. As Figure 1 shown, according to aspects of the present disclosure, BS 110a includes a sidelink manager 112 that transmits recovery information for sidelink communication to one or more UEs communicating via a sidelink channel. In some examples, sidelink manager 112 may generate parity check information for sidelink communication as recovery information. As Figure 1 shown, according to aspects of the present disclosure, UEs 120a, 120b, 120c include sidelink managers 122 that may communicate with one or more other UEs via a sidelink channel, recover sidelink communication using recovery information from a base station or another UE, and / or generate and transmit recovery information for one or more other UEs.

[0050] The wireless communication network 100 may also include a relay station (e.g., relay station 110r) (also referred to as a relay, etc.), which receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and sends the transmissions of the data and / or other information to a downstream station (e.g., UE 120 or BS 110), or the relay station relays transmissions between the UEs 120 to facilitate communication between the devices.

[0051] The network controller 130 may be coupled to a set of BSs 110 and provide coordination and control of these BSs 110. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other via a wireless or wired backhaul (e.g., directly or indirectly).

[0052] The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premise equipment (CPE), cellular phone, smart phone, 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 equipment, biometric sensor / device, wearable device (such as a smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which may communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node may provide connectivity to a network (e.g., a wide area network such as the Internet or a cellular network) or provide connectivity to the network, for example, via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0053] Some wireless networks (e.g., LTE) utilize 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 also often referred to as frequency tones, frequency bins, etc. Each subcarrier can be modulated with data. Generally speaking, modulation symbols are sent in the frequency domain for OFDM and in the time domain for 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 can be 15 kHz, and the minimum resource allocation (referred to as a "resource block" (RB)) can be 12 subcarriers (or 180 kHz). Thus, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal Fast Fourier Transform (FFT) size can 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 1.08 MHz (i.e., 6 resource blocks), and for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, there can be 1, 2, 4, 8, or 16 subbands, respectively.

[0054] While aspects of the examples described herein may be associated with LTE technology, aspects of the present disclosure may be applicable to other wireless communication systems, such as 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 the beam direction can be configured dynamically. MIMO transmission with precoding can also be supported. The MIMO configuration in the DL can support up to 8 transmit antennas (multi-layer DL transmission with up to 8 streams) and up to 2 streams per UE. Multi-layer transmission with up to 2 streams per UE can be supported. Aggregation of multiple cells can be supported using up to 8 serving cells.

[0055] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all of the devices and equipment within its service area or cell. The scheduling entity can be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for the scheduled communication, the subordinate entities utilize 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 the other UEs can utilize the resources scheduled by the UE for wireless communication. In some examples, a UE can act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In the mesh network example, UEs can communicate directly with each other in addition to communicating with the scheduling entity.

[0056] In Figure 1 it, the solid line with double arrows 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. The thin dashed line with double arrows indicates the interfering transmission between the UE and the BS.

[0057] Figure 2 illustrates an example logical architecture of a distributed radio access network (RAN) 200, which can be implemented in the wireless communication network 100 illustrated in Figure 1 it. The 5G access node 206 may include an access node controller (ANC) 202. The ANC 202 may be a central unit (CU) of the distributed RAN 200. The backhaul interface to the next-generation core network (NG-CN) 204 may be terminated at the ANC 202. The backhaul interface to an adjacent next-generation access node (NG-AN) 210 may be terminated at the ANC 202. The ANC 202 may include one or more TRPs 208 (e.g., cells, BSs, gNBs, etc.).

[0058] The TRP 208 may be a distributed unit (DU). The TRP 208 may be connected to a single ANC (e.g., ANC 202) or more than one ANC (not illustrated). For example, for RAN sharing, radio as a service (RaaS), and service-specific AND deployments, the TRP 208 may be connected to more than one ANC. Each TRP 208 may include one or more antenna ports. The TRP 208 may be configured to serve traffic to the UE individually (e.g., dynamically select) or jointly (e.g., joint transmission).

[0059] The logical architecture of the distributed RAN 200 may support fronthaul solutions across different deployment types. For example, the logical architecture may be based on transport network capabilities (e.g., bandwidth, latency, and / or jitter).

[0060] The logical architecture of the distributed RAN 200 may share features and / or components with LTE. For example, the next-generation access node (NG-AN) 210 may support dual connectivity with NR and may share a common fronthaul for LTE and NR.

[0061] The logical architecture of the distributed RAN 200 may enable cooperation between and among the TRPs 208, e.g., within a TRP and / or across TRPs via the ANC 202. An inter-TRP interface may not be used.

[0062] The logical functions can be dynamically distributed in the logical architecture of the distributed RAN 200. The radio resource control (RRC) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, media access control (MAC) layer, and physical (PHY) layer can be adaptively placed at the DU (e.g., TRP 208) or CU (e.g., ANC 202).

[0063] Figure 3 An example physical architecture of a distributed RAN 300 in accordance with aspects of the present disclosure is illustrated. A centralized core network unit (C-CU) 302 may host core network functions. The C-CU 302 may be centrally deployed. The C-CU 302 functionality may be offloaded (e.g., to an advanced wireless service (AWS)) to attempt to handle peak capacity.

[0064] A centralized RAN unit (C-RU) 304 may host one or more ANC functions. Optionally, the C-RU 304 may locally host core network functions. The C-RU 304 may have a distributed deployment. The C-RU 304 may be close to the network edge.

[0065] The DU 306 may host one or more TRPs (edge node (EN), edge unit (EU), radio head (RH), smart radio head (SRH), etc.). The DU may be located at the edge of the network with radio frequency (RF) functionality.

[0066] Figure 4 Illustrated are example components of a BS 110a and a UE 120a (as depicted in Figure 1 which may be used to implement aspects of the present disclosure. For example, the antenna 452, processors 466, 458, 464, and / or controller / processor 480 of the UE 120a and / or the antenna 434, processors 420, 430, 438, and / or controller / processor 440 of the BS 110a may be used to perform the various techniques and methods described herein with reference to Figures 8-9 the description.

[0067] At BS 110a, the transmit processor 420 may receive data from data source 412 and control information from controller / processor 440. The control information may be used for 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. The data may be used for physical downlink shared channel (PDSCH), etc. The processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols (e.g., primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, and / or reference symbols, if applicable, and may provide output symbol streams to modulators (MOD) 432a through 432t. Each modulator 432 may process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may 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 432a through 432t may be transmitted via antennas 434a through 434t, respectively.

[0068] At UE 120a, antennas 452a through 452r may receive the downlink signals from base station 110a and may provide the received signals to demodulators (DEMOD) 454a through 454r in the transceiver, respectively. Each demodulator 454 may condition (e.g., filter, amplify, down-convert, and digitize) its respective received signal to obtain an input sample. Each demodulator may further process the input sample (e.g., for OFDM, etc.) to obtain received symbols. The MIMO detector 456 may obtain the received symbols from all demodulators 454a through 454r, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. The receive processor 458 may process (e.g., demodulate, de-interleave, and decode) the detected symbols, provide the decoded data for UE 120a to data sink 460, and provide the decoded control information to controller / processor 480.

[0069] On the uplink, at the UE 120a, the transmit processor 464 may receive and process data from the data source 462 (e.g., for the physical uplink shared channel (PUSCH)) and control information from the controller / processor 480 (e.g., for the physical uplink control channel (PUCCH)). The transmit processor 464 may also generate reference symbols for a reference signal (e.g., sounding reference signal (SRS)). The symbols from the transmit processor 464 may be precoded by the TX MIMO processor 466 when applicable, further processed by the demodulators 454a through 454r in the transceiver (e.g., for SC-FDM, etc.), and transmitted to the base station 110a. At the BS 110a, the uplink signal from the UE 120a may be received by the antenna 434, processed by the modulator 432, detected by the MIMO detector 436 when applicable, and further processed by the receive processor 438 to obtain the decoded data and control information transmitted by the UE 120a. The receive processor 438 may provide the decoded data to the data sink 439 and the decoded control information to the controller / processor 440.

[0070] The controller / processors 440 and 480 may direct operations at the BS 110a and the UE 120a, respectively. The processor 440 and / or other processors and modules at the BS 110a may execute or direct the execution of the processes for the techniques described herein. For example, as Figure 4 shown, according to aspects described herein, the controller / processor 440 of the BS 110a has a sidelink manager 441 that conveys recovery information for sidelink communication to one or more UEs communicating via a sidelink channel. As Figure 4 shown, according to aspects described herein, the controller / processor 480 of the UE 120a has a sidelink manager 481 that may communicate with one or more other UEs via a sidelink channel, recover sidelink communication with recovery information from the base station or another UE, and / or generate and convey recovery information for one or more other UEs. Although shown at the controller / processor 480 and the controller / processor 440, other components of the UE 120a and the BS 110a may also be used to perform the operations described herein. The memories 442 and 482 may store data and program code for use by the BS 110a and the UE 120a, respectively. The scheduler 444 may schedule the UEs for data transmission on the downlink and / or uplink.

[0071] While reference is made to Figure 1 and Figure 4UE 120a is described as communicating with the BS and / or within the network, but UE 120a may be configured to communicate directly with another UE 120 / directly transmit to another UE 120, or communicate with / transmit to another wireless device without relaying the communication through the network. In some embodiments, Figure 4 The BS 110a illustrated and described above is an example of another UE 120.

[0072] In some cases, two or more lower-level entities (e.g., UEs) may use sidelink signals to communicate with each other. Real-world applications of such sidelink communication may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communication, Internet of Everything (IoE) communication, IoT communication, mission-critical mesh, and / or various other suitable applications. Generally, a sidelink signal may refer to a signal that is conveyed from one lower-level entity (e.g., UE1) to another lower-level entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., a UE or BS), even though the scheduling entity may be used for scheduling and / or control purposes. In some examples, sidelink signals may be conveyed using licensed spectrum (different from wireless local area network (WLAN), which typically uses unlicensed spectrum).

[0073] Figure 5A and 5B FIG. illustrates a graphical representation of an example vehicle-to-everything (V2X) system in accordance with some aspects of the present disclosure. For example, Figure 5A and 5B The vehicles shown in may communicate via sidelink channels and may perform sidelink CSI reporting, as described herein.

[0074] In Figure 5A and 5B The V2X systems provided in provide two complementary transmission modes. In Figure 5A The first transmission mode, illustrated by way of example in, involves direct communication (e.g., also referred to as sidelink communication) between parties in close proximity to each other in a local area. In Figure 5B The second transmission mode, illustrated by way of example in, involves network communication through the network, which may be implemented through the Uu interface (e.g., the wireless communication interface between a radio access network (RAN) and a UE).

[0075] Referring to Figure 5A, the V2X system 500 (e.g., including vehicle-to-vehicle (V2V) communication) is illustrated with two vehicles 502, 504. The first transmission mode allows for direct communication between different parties in a given geographical location. As illustrated, a vehicle may have a wireless communication link 506 with an individual through the PC5 interface (i.e., vehicle-to-pedestrian (V2P), e.g., via a UE). Communication between vehicles 502 and 504 may also occur through the PC5 interface 508. In a similar manner, communication from vehicle 502 to other highway components (e.g., roadside service unit (RSU) 510, such as a traffic signal or sign) (i.e., vehicle-to-infrastructure (V2I)) may occur through the PC5 interface 512. For Figure 5A each communication illustrated in, two-way communication can occur between the elements, so each element can be both a transmitter and a receiver of information. The V2X system 500 can be a self-managed system implemented without the assistance of a network entity. The self-managed system can achieve improved spectral efficiency, reduced cost, and increased reliability because there is no network service interruption during a handover operation for a moving vehicle. The V2X system can be configured to operate in licensed or unlicensed spectrum, whereby any vehicle equipped with the system can access a shared frequency and share information. Such coordinated / shared spectrum operation allows for safe and reliable operation.

[0076] Figure 5B The V2X system 550 for communication between vehicle 552 and vehicle 554 through a network entity 556 is shown. These network communications can occur through a discrete node (such as a base station, e.g., an eNB or a gNB) that sends information to and receives information from vehicles 552, 554 (e.g., relays information between vehicles 552, 554). Network communication through the vehicle-to-network (V2N) links 558 and 510 can be used, for example, for long-range communication between vehicles, such as for communicating that there is a traffic accident at a certain distance ahead along a road or highway. Other types of communication can be sent by the node to the vehicles, such as traffic flow conditions, road hazard warnings, environmental / weather reports, service station availability, and other similar examples. Such data can be obtained from cloud-based shared services.

[0077] In some cases, two or more lower-level entities (e.g., UEs) may communicate with each other using sidelink signals. As described above, V2V and V2X communications are examples of communications that may be transmitted via sidelink. When a UE is transmitting sidelink communication on a subchannel of a frequency band, the UE typically cannot receive another communication in that frequency band (e.g., another sidelink communication from another UE). Other applications of sidelink communication may include public safety or service announcement communication, proximity service communication, UE-to-network relay communication, device-to-device (D2D) communication, Internet of Everything (IoE) communication, Internet of Things (IoT) communication, mission-critical mesh communication, and other suitable applications. Generally speaking, sidelink may refer to a direct link between one lower-level entity (e.g., UE1) and another lower-level entity (e.g., UE2). Thus, sidelink can be used to transmit and receive communications (also referred to herein as sidelink signals) without relaying the communication through a scheduling entity (e.g., BS), even though the scheduling entity may be used for scheduling or control purposes. In some examples, sidelink signals may be conveyed using licensed spectrum (different from wireless local area networks, which typically use unlicensed spectrum).

[0078] Various sidelink channels can be used for sidelink communication, including Physical Sidelink Discovery Channel (PSDCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), and Physical Sidelink Feedback Channel (PSFCH). PSDCH can carry discovery expressions that enable neighboring devices to discover each other. PSCCH can carry control signaling (such as sidelink resource configuration and other parameters for data transmission), while PSSCH can carry data transmission.

[0079] For operations regarding PSSCH, a UE may perform transmission or reception in a time slot on a carrier. Generally, within the duration of a time slot, reservation or allocation of transmission resources for sidelink transmission is performed on subchannels of a frequency band. The NR sidelink can support both a case where all symbols in a time slot are available for sidelink and another case where only a coherent subset of symbols in a time slot is available for sidelink.

[0080] PSFCH can carry feedback, such as channel state information (CSI) related to sidelink channel quality. A sequence-based PSFCH format with one symbol (excluding the AGC training period) can be supported. The following formats are possible: a PSFCH format based on PUCCH format 2, and a PSFCH format that spans all symbols available for sidelink in a time slot.

[0081] Figure 6 is a UE (e.g., Figure 1An example transmission timeline 600 for sidelink communication (broadcast and multicast device-to-device or D2D) between the UEs 110 shown in. As mentioned above, with reference to Figure 5A and 5B , the sidelink generally refers to a link between two users, or user relays can be used in different scenarios and different applications. As previously described, when a UE transmits sidelink communication on a subchannel of a frequency band, the UE generally cannot receive another communication in that frequency band (e.g., another sidelink communication from another UE). Thus, sidelink communication can be referred to as half-duplex. Thus, UEs 0, 1, and 5 that respectively transmit sidelink communications 612, 614, and 616 cannot receive sidelink communications from each other. That is, UE 0 cannot receive sidelink transmissions 614 and 616. Similarly, UE 2 cannot respectively receive sidelink transmissions 624 and 632 from UEs 3 and 4. Moreover, UE 3 cannot receive the sidelink transmission 622 from UE 2, and UE 4 cannot receive the sidelink transmission 634 from UE 2. In aspects of the present disclosure, for a UE or wireless node that cannot receive a sidelink transmission, the (s)idelink transmission(s) that cannot be received can be referred to as "erased" because the UE has no information about that sidelink transmission. This is different from other cases where a UE fails to decode a transmission because in those cases, the UE can retain some information about the transmission that the UE fails to decode, and the UE can combine the retained information with retransmissions received by the UE to determine the transmission that the UE fails to decode.

[0082] According to previously known techniques, in NR sidelink communication, resource allocation is reservation-based. In these techniques, resource allocation is performed in units of subchannels in the frequency domain, and resource allocation in the time domain is limited to one time slot. In previously known techniques, transmissions can reserve resources in the current time slot and up to two future time slots. Reservation information can be carried in sidelink control information (SCI). In previously known techniques, sidelink control information (SCI) can be transmitted in two phases. The first-phase SCI (SCI-1) can be transmitted on the physical sidelink control channel (PSCCH) and contains resource reservation information and the information required to decode the second-phase SCI (SCI-2). SCI-2 can be transmitted on the physical sidelink shared channel (PSSCH) and contains the information required to decode data on the shared channel (SCH) and to provide feedback (e.g., acknowledgement (ACK) or negative acknowledgement (NAK)) on the physical sidelink feedback channel (PSFCH).

[0083] Figure 7An example transmission timeline 700 for explaining sidelink resource reservation according to prior art is shown. The SCI-1 transmitted by the UE at 712 can reserve resources at 712, 732, and 742. Similarly, another SCI-1 transmitted by the UE at 714 can reserve resources at 744 and 774.

[0084] According to prior art, erasure coding can be used to encode data so that a receiving device can recover a portion of the data erased from the transmission. That is, an erasure code or an error correction code can be used to transform the data so that the receiving party can recover the original data from a portion of the data. A single parity check code can correct one erasure. For example, when the input vector is [a, b, c], a single parity check code can be used to encode the input vector to form an encoded vector [a, b, c, a b c], and then the encoded vector is transmitted. In this example, any single erasure can be recovered. For example, if the received vector is [a,?, c, a b c], the erased element (i.e., b) can be recovered by adding the other received elements: a c (a b c) = b. This can be regarded as a linear system (over a Galois field) with three variables, and any three of the four constraints are linearly independent:

[0085]

[0086] Any three constraints (i.e., one erasure among the four constraints) are sufficient to find the three variables.

[0087] Other forms of erasure decoding can be used to achieve the recovery of two or more erasures. Reed-Solomon and other maximum distance separable (MDS) codes can achieve the recovery of two or more erasures. In some aspects, the erasure code can include a parity check code, a Reed-Solomon code, and / or an MDS code. In some cases, the erasure code can include other suitable codes, such as Raptor codes, etc. Generally, an erasure code can be designed such that any k of the n symbol codewords are sufficient to decode k information symbols. For example, the erasure codes described below can be used to recover up to two erasures:

[0088]

[0089] Example sidelink communication recovery

[0090] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for recovering, e.g., sidelink communications that are received in error by a wireless node or missed by the wireless node due to the wireless node transmitting while sidelink communications are occurring. In some cases, a UE may be configured to communicate via half-duplex communication for sidelink communications. In other cases, a UE may only support half-duplex communication for sidelink communications. When a UE transmits sidelink communications in a frequency band, the UE may be unable to receive another communication in the same frequency band (e.g., another sidelink communication from another UE), e.g., due to half-duplex support and / or configuration for sidelink communications. In some cases, a UE may receive sidelink communications in error, e.g., due to an undesired channel quality or mobility scenario. In aspects of the present disclosure, a wireless node may receive sidelink communications and transmit recovery information in a recovery time slot. A UE that is transmitting during a period (e.g., time slot) of sidelink communication may receive the recovery information and recover sidelink communications that were received in error or missed by the UE while the UE was transmitting (e.g., determine the content of the sidelink communications). In some aspects of the present disclosure, a wireless node may generate parity information and / or other erasure code information (e.g., redundant information) as recovery information that a UE may use to recover sidelink communications. In some aspects of the present disclosure, a wireless node may transmit a repetition of the sidelink communication as recovery information. The techniques described herein for recovering sidelink communications may achieve desired wireless performance from sidelink communications, such as desired data rates, latency, and / or reliability.

[0091] Figure 8 is a flow diagram illustrating an example operation 800 that may be performed by a wireless node in accordance with some aspects of the present disclosure. For example, operation 800 may be performed by a UE, BS, or RSU as shown in Figure 1 , 4 or 5A. As used herein, a wireless node may refer to a wireless communication device, such as a UE, BS, or RSU.

[0092] Operation 800 begins at block 802, where a wireless node may receive a plurality of sidelink communications, each sidelink communication between two user equipments (UEs). At block 804, the wireless node transmits recovery information in a recovery time slot, where the recovery information is for recovering at least one of the sidelink communications of the two UEs or at least one of the sidelink communications of other UEs that were transmitted when at least one of the sidelink communications occurred, and where the recovery time slot is for transmission of the recovery information. Although operation 800 is described herein with respect to a wireless node that transmits recovery information and is separate from the UEs communicating via sidelink communications to facilitate understanding, aspects of the present disclosure may be applied to transmitters of sidelink communications that also transmit corresponding recovery information for such sidelink communications.

[0093] Figure 9 is a flow chart illustrating an example operation 900 executable by a UE in accordance with certain aspects of the present disclosure. For example, operation 900 may be performed by the UE or base station shown in Figure 1 , 4 , 5A, and 5B.

[0094] Operation 900 begins at block 902, where a first UE may communicate sidelink communication with a second UE. In aspects, the first UE communicating with the second UE may involve the first UE transmitting and / or receiving sidelink communication to and / or from the second UE. At block 904, the first UE receives recovery information in a recovery time slot, where the recovery information is for recovering at least one of the sidelink communications of one or more third UEs transmitted when the sidelink communication occurred, and where the recovery time slot is for the transmission of the recovery information. At block 906, the first UE determines another sidelink communication transmitted by a wireless node (e.g., a UE, BS, or RSU) based on the sidelink communication and the recovery information. In aspects, the wireless node at block 906 may include one of the second UE, the third UE, and / or a separate wireless node (such as another UE, BS, or RSU).

[0095] In accordance with aspects of the present disclosure, slot-level erasure decoding may be used to achieve the recovery of missed (e.g., erased) sidelink communications or the recovery of received sidelink communications with errors. As described in block 906 above Figure 9 , recovering a missed sidelink communication or recovering a sidelink communication with an error may be an example of determining another sidelink communication.

[0096] Figure 10It is a signaling flow that illustrates example signaling for restoring sidelink communication according to certain aspects of the present disclosure. In this example, at 1002, a first UE 120a receives one or more first sidelink communications from a second UE 120b, and a radio node 140 (e.g., which may be another UE, BS, RSU, or a group leader for sidelink communication) may also receive the first sidelink communication(s). At 1004, the first UE 120a may receive one or more second sidelink communications from a third UE 120b. At 1006, in the same time domain resource unit (e.g., time slot) as the second sidelink communication(s), the second UE 120b may transmit one or more third sidelink communications, where the first UE 120a may miss receiving the third sidelink communication(s) due to, for example, half-duplex support and / or configuration of the sidelink communication. In some cases, at 1006, the first UE 120a may receive the third sidelink communication(s) with errors. At 1006, the radio node 140 may receive the third sidelink communication(s) from the second UE 120b. At 1008, the radio node 140 may generate recovery information for the sidelink communication transmitted by the second UE 120b via, for example, one or more erasure codes. In various aspects, the radio node 140 may select sidelink communications (such as TB and / or SCI payloads) for grouping and / or replication based on various criteria further described herein for generating recovery information. At 1010, the radio node 140 may transmit the recovery information to the first UE 120a, and at 1012, the UE 120 may use the recovery information to recover the missed third sidelink communication(s) or the third sidelink communication(s) received with errors. Although this example is described herein with the radio node 140 transmitting the recovery information to facilitate understanding, various aspects of the present disclosure may be applied to the second UE and / or the third UE generating and transmitting the recovery information.

[0097] In various aspects of the present disclosure, one or more time slots that provide redundancy for a previous transmission to form, for example, an MDS code may be used for sidelink communication recovery. A time slot with recovery information may enable a receiving UE to use the information from the time slot when the UE is receiving, and use the recovery information to recover transmissions that are erased due to, for example, the half-duplex aspect of the sidelink communication.

[0098] Figure 11 is an example transmission timeline 1100 of sidelink communication (broadcast and multicast device-to-device or D2D) between UEs (e.g., Figure 1 the UE 110 shown in Figure 6As described, UE 0, UE 1, and UE 5 that respectively transmit sidelink communications 1112, 1114, and 1116 cannot receive sidelink communications from each other. That is, UE 0 cannot receive sidelink transmissions 1114 and 1116. Similarly, UE 2 cannot receive sidelink transmissions 1124 and 1132 from UE 3 and UE 4, respectively. Also, UE 3 cannot receive sidelink transmission 1122 from UE 2, and UE 4 cannot receive sidelink transmission 1134 from UE 2. In aspects of the present disclosure, a wireless node may transmit recovery information in a later time slot 1140 or 1150. Each UE may use recovery information having information related to the UE's own transmissions and the transmissions received in time slots 1110, 1120, and 1130 to recover sidelink transmissions missed by the UE or received in error, e.g., because the UE was transmitting during one or more of time slots 1110, 1120, or 1130.

[0099] As previously referenced Figure 7 As described, an SCI-1 transmission may carry reservation information for up to 2 future transmissions. Thus, it is beneficial for a wireless node to recover a missed SCI-1 or a received SCI-1 in error, and even without recovering data, conflicts can be avoided and reliability can be improved by receiving those reservations for future transmissions.

[0100] In aspects of the present disclosure, there is typically one SCI-1 size in a resource pool.

[0101] In aspects of the present disclosure, a wireless node may apply erasure decoding to SCI-1 transmissions within a single subchannel across time slots (i.e., as Figure 8 described, to generate recovery information).

[0102] In aspects of the present disclosure, different time slots may have different numbers of transmitted PSCCHs, and a wireless node encoding the PSCCH (and SCI-1 in the PSCCH) may use dummy bits (e.g., all zeros) for time slots that do not have an SCI-1 in the subchannel.

[0103] In aspects of the present disclosure, a UE that receives recovery information may determine the absence of an SCI-1 in a subchannel within a time slot based on the dummy bit value, an invalid CRC, or an explicit indication from the transmitter of the recovery information (e.g., a field in the recovery information or another transmission).

[0104] Figure 12AExemplary transmission timeline 1200 in accordance with aspects of the present disclosure. In this exemplary transmission timeline, a wireless node (e.g., a UE not shown) receives PSCCHs 1202, 1204, and 1206 all transmitted in subchannel 0, and transmits recovery information for those PSCCHs in subchannel 0 at 1208. Similarly, the wireless node receives PSCCHs 1212 and 1216 transmitted in subchannel 1, and transmits recovery information 1218 for PSCCHs 1212 and 1216. Since no PSCCH is transmitted at 1214 (as indicated by the cross-hatched symbol), at 1218, the wireless node may use dummy bits for the non-existent PSCCH when generating the recovery information. Similarly, the wireless node receives PSCCHs 1222 and 1224, and may use dummy bits for the non-existent PSCCH at 1226 when generating recovery information 1228.

[0105] In accordance with aspects of the present disclosure, a wireless node may collect all SCI-1s (e.g., from PSCCHs) in a subchannel set within a time period of a time slot and transmit recovery information for all SCI-1s in a single transmission (e.g., a media access control control element (MAC-CE)). That is, the wireless node may combine SCI-1 messages received in the subchannel set within the time period of the time slot, where the recovery information may include the combined SCI-1 messages, and the wireless node may transmit the recovery information in a single transmission such as a MAC-CE or other control signaling.

[0106] Figure 12B Exemplary transmission timeline 1250 in accordance with aspects of the present disclosure. In this exemplary transmission timeline, a wireless node (e.g., a UE not shown) receives PSCCHs 1252, 1254, 1256, 1262, 1266, 1272, and 1274 transmitted in subchannels 0, 1, and 2, and transmits recovery information for those PSCCHs in subchannel 0 at 1258. Since no PSCCH is transmitted at 1264 and 1276 (as indicated by the cross-hatched symbols), the wireless node may use dummy bits for the non-existent PSCCHs when generating the recovery information at 1258.

[0107] In accordance with aspects of the present disclosure, erasure decoding may be applied to data transmissions (e.g., on a shared channel (SCH)) to enable recovery of missed (e.g., erased) sidelink data communications or recovery of received erroneous sidelink communications.

[0108] In various aspects of the present disclosure, the SCH TB can have different sizes. Two data transmissions spanning the same number of subchannels can have TBs of different sizes because these transmissions can be conveyed with different modulation and coding schemes (MCSs). The data transmissions can be conveyed using different redundancy versions (RVs), or can span different numbers of subchannels. Thus, it is not desirable to apply the simple decoding described above for SCI-1 across TBs.

[0109] In various aspects of the present disclosure, a wireless node can encode and combine sidelink data transmissions to generate recovery information for the sidelink data transmissions.

[0110] In various aspects of the present disclosure, a wireless node can simply relay (e.g., repeat) a sidelink data transmission as recovery information for that sidelink data transmission.

[0111] In various aspects of the present disclosure, when combining data transmissions to generate recovery information, it is desirable to combine data transmissions in different time slots. Combining data transmissions from different time slots makes it less likely that the UE will miss more than two of the combined data transmissions (since the data transmissions are in different time slots), and thus it is more likely that the UE will be able to use the recovery information to recover missed data transmissions or recover data transmissions with errors.

[0112] In various aspects of the present disclosure, a wireless node can group TBs from data transmissions, use an erasure code (e.g., an MDS code) to encode the TBs in the group to generate an encoded group, use a low-density parity-check (LDPC) code to encode the encoded group to generate recovery information, and then transmit the recovery information. In aspects, the encoded group can include redundant symbol(s) and / or parity symbol(s). That is, a wireless node can use an erasure code to encode the TBs in the group to generate redundant symbol(s) and / or parity symbol(s). In certain aspects, the encoded group can be the recovery information such that a wireless node can use an erasure code (e.g., an MDS code) to encode the TBs in the group to generate recovery information. For example, a group of TBs can be encoded to generate a parity symbol P0, which is the recovery information. Subsequently, the parity symbol P0 can be encoded using LDPC and transmitted to other UEs.

[0113] In various aspects of the present disclosure, a wireless node can group TBs from data transmissions, use an LDPC code to encode the TBs in the group, use an erasure code (e.g., an MDS code) to encode the LDPC-encoded TBs within the group to generate recovery information, and transmit the recovery information.

[0114] In various aspects of the present disclosure, the encoded TBs within the group can be rate matched to the same number of encoded bits.

[0115] In aspects of the present disclosure, the cyclic redundancy check (CRC) of each transport block (TB) can be considered part of the TB and combined with all CRCs of all TBs.

[0116] According to aspects of the present disclosure, a wireless node can remove the CRC from each TB and generate a new CRC for the combined TBs in a group, padding the TBs if needed so that all TBs have the same size.

[0117] In aspects of the present disclosure, a wireless node can group each TB from different time slots to generate recovery information for the TBs in the group.

[0118] Figure 13 is an exemplary transmission timeline 1300 according to aspects of the present disclosure. In this exemplary transmission timeline, a wireless node (e.g., a UE not shown) receives TBs 1312, 1314, and 1316 all transmitted in time slot 1310, TBs 1322 and 1324 transmitted in time slot 1320, and TBs 1332 and 1334 transmitted in time slot 1330. In this exemplary transmission timeline, the wireless node groups TBs 1312, 1324, and 1332 and generates recovery information that the wireless node transmits at 1342 based on those TBs. Similarly, the wireless node groups TBs 1316, 1322, and 1334 and generates recovery information that the wireless node transmits at 1346 based on those TBs. Finally, in this exemplary transmission timeline, the wireless node groups TB 1314 by itself and generates recovery information that the wireless node transmits at 1344 based on that TB. It can be noted that each group of TBs includes at most one TB from each of time slots 1310, 1320, and 1330.

[0119] In aspects of the present disclosure, a wireless node may desire to group TBs based on reducing the number of padding bits added during generation of recovery information. Thus, in exemplary transmission timeline 1300, recovery information 1342 is generated based on TBs each occupying one subchannel in one time slot, while recovery information 1346 is generated based on two TBs each occupying two subchannels in one time slot. Finally, recovery information 1344 is based on a transmission occupying one subchannel in one time slot. This grouping uses a smaller number of padding bits compared to a group where TBs 1322 and 1334 are in a different group from other TBs occupying one subchannel in one time slot.

[0120] According to aspects of the present disclosure, a wireless node can group TBs based on the size of the TBs and add zero padding or additional parity check information (e.g., parity bits) within each group.

[0121] In aspects of the present disclosure, a wireless node may cluster transport blocks (TBs) based on a layer one (L1) destination identifier (ID) per TB.

[0122] According to aspects of the present disclosure, a wireless node may cluster TBs based on the starting subchannel used to transmit each of the TBs. In the exemplary transmission timeline 1300, TBs 1312, 1322, and 1332 may be clustered based on each TB starting in subchannel 0.

[0123] In aspects of the present disclosure, a wireless node may cluster TBs while excluding high-priority TBs. This may be desirable as high-priority TBs are retransmitted.

[0124] According to aspects of the present disclosure, a wireless node may cluster TBs based on a signal in SCI-2 or MAC-CE indicating which TBs are to be clustered together.

[0125] In aspects of the present disclosure, a wireless node may cluster TBs based on a combination of the various criteria described above.

[0126] According to aspects of the present disclosure, a wireless node may determine which TBs are to be clustered and generate recovery information for a subset of sidelink transmissions (e.g., erasure coding). The wireless node may determine which TBs to include for generating the recovery information based on an indication in SCI-2 or MAC-CE.

[0127] In aspects of the present disclosure, the selection of which TBs to include when generating recovery information may be based on the priority of the TB, the amount of remaining time in the packet delay budget (PDB), whether the wireless node had a CRC pass or fail when receiving the PSSCH carrying the TB, and / or the size of the TB (i.e., transport block size (TB)).

[0128] According to aspects of the present disclosure, when performing LDPC coding on a TB, as described above, the wireless node may use the RV = 0 redundant version of each TB.

[0129] In aspects of the present disclosure, when performing LDPC coding on a TB, as described above, the wireless node may use the RV used in the original transmission of the TB (e.g., sidelink transmission).

[0130] In accordance with aspects of the present disclosure, a wireless node may generate recovery information by concatenating all TBs in a time slot to form a TB group for each corresponding time slot for sidelink communication; padding or repeating some of the TBs in the TB group to form a padded group such that the size of the group is consistent with the size of groups from other time slots; combining the TB groups across time slots; and then generating recovery information (e.g., using an MDS code) for the group combination across time slots. In these aspects, a UE using the recovery information decodes all TBs (even in normal time slots), not just the TBs addressed to the UE.

[0131] The size of SCI-2 may vary between different time slots, although both have limited range and granularity compared to the SCH.

[0132] In accordance with aspects of the present disclosure, a wireless node may include SCI-2 content as part of the SCH before generating recovery information for the SCH.

[0133] In aspects of the present disclosure, a wireless node may group SCI-2s received in sidelink transmissions (such as SCI-2 payloads) (e.g., using one or more of the criteria for grouping TBs described above), generate recovery information for the SCI-2s within the group using an erasure code (e.g., an MDS code), encode the recovery information using a polar code, and transmit the encoded recovery information.

[0134] In accordance with aspects of the present disclosure, a wireless node may group SCI-2s received in sidelink transmissions (e.g., using one or more of the criteria for grouping TBs described above), encode the SCI-2s in the group using a polar code, encode the polar-coded SCI-2s within the group using an erasure code (e.g., an MDS code) to generate recovery information, and transmit the recovery information.

[0135] In aspects of the present disclosure, when generating recovery information for SCI-1 or sidelink data transmission, a wireless node may exclude SCI-2.

[0136] In accordance with aspects of the present disclosure, a wireless node may generate recovery information by replicating certain sidelink transmissions from a particular time-domain resource unit (e.g., a time slot). That is, the wireless node may transmit recovery information that includes a replication (i.e., a repetition) of certain sidelink transmissions. Referring to operation 800, the recovery information may include one or more replications of multiple sidelink communications. The time slot to be repeated may be selected based on the number of high-priority transmissions in the time slot, the number of UEs affected by a missed (i.e., not received during the time slot) time slot, the number of remaining retransmissions for a TB in the time slot, or the proximity of the wireless node to the UEs transmitting during the time slot. In aspects of the present disclosure, the wireless node may use a zoning ID or a reference signal received power (RSRP) from a UE to determine the proximity to the UE.

[0137] Figure 14 is an example transmission timeline 1400 of sidelink communications between UEs (e.g., Figure 1 UE 110 as shown in ) in accordance with various aspects of the present disclosure. In the exemplary transmission timeline, UEs 0, 1, 3, 4, and 5 transmit sidelink communications 1412, 1414, 1424, 1432, and 1416, respectively. Similarly, UE 2 transmits sidelink communications 1422 and 1434. In this exemplary transmission timeline, a wireless node (e.g., a UE or an RSU, not shown) repeats the transmission of time slot 1410 in time slot 1440. The wireless node also repeats the transmission of time slot 1430 in time slot 1450.

[0138] In aspects of the present disclosure, the wireless node transmitting the recovery information may be a UE designated by the network (e.g., selected by a base station), a roadside service unit (RSU), a group leader, or a UE that has received all previous transmissions to be included in a parity time slot.

[0139] In accordance with some aspects of the present disclosure, a UE that reserves transmission resources in a recovery time slot (e.g., a time slot to be used for transmitting recovery information) may be selected to generate and transmit the recovery information. That is, the UE (e.g., an RSU) may indicate to other devices that the UE will transmit recovery information by transmitting an SCI-1 that reserves transmission resources in the recovery time slot. It can be considered that the UE has "voluntarily" transmitted the recovery information.

[0140] Referring to operation 900, a first UE may determine another sidelink communication with an erasure code based on the sidelink communication and the recovery information. For example, the recovery information may include parity check information from a parity check code and / or information from other suitable erasure codes such as Reed-Solomon codes, MDS codes, and / or Raptor codes.

[0141] In some aspects, a data block group (e.g., a transport block and / or a code block group) may be encoded using an erasure code to recover sidelink communications. At block 906, a first UE may decode another sidelink communication using an erasure code based on recovery information including a transport block group encoded with an erasure code. For some aspects, a payload group for sidelink control information may be encoded using an erasure code to recover sidelink communications. At block 906, a first UE may decode another sidelink communication using an erasure code based on recovery information including a payload group for sidelink control information encoded with an erasure code.

[0142] Figure 15 Illustrated is a communication device 1500 that may include various components (e.g., corresponding to apparatus plus function components) configured to perform operations for the techniques disclosed herein, such as Figure 8 the operations illustrated in. The communication device 1500 includes a processing system 1502 coupled to a transceiver 1508. The transceiver 1508 is configured to transmit and receive signals for the communication device 1500 (such as the various signals described herein) via an antenna 1510. The processing system 1502 may be configured to perform processing functions for the communication device 1500, including processing signals received and / or to be transmitted by the communication device 1500.

[0143] The processing system 1502 includes a processor 1504 coupled to a computer-readable medium / memory 1512 via a bus 1506. In some aspects, the computer-readable medium / memory 1512 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1504, cause the processor 1504 to perform Figure 8The operations described in, or other operations for recovery, such as side - link communications that are received in error or missed by a wireless node due to the wireless node transmitting while side - link communications are occurring. In some aspects, the computer - readable medium / memory 1512 stores: code 1514 for receiving a plurality of side - link communications, each side - link communication being between two user equipments (UEs); and code 1516 for transmitting recovery information in a recovery time slot, where the recovery information is for recovering at least one of the side - link communications of the two UEs or other UEs that were transmitted when at least one of the side - link communications occurred, and where the recovery time slot is for the transmission of the recovery information. In some aspects, the processor 1504 has circuitry configured to implement the code stored in the computer - readable medium / memory 1512. The processor 1504 includes: circuitry 1520 for receiving a plurality of side - link communications, each side - link communication being between two user equipments (UEs); and circuitry 1524 for transmitting recovery information in a recovery time slot, where the recovery information is for recovering at least one of the side - link communications of the two UEs or other UEs that were transmitted when at least one of the side - link communications occurred, and where the recovery time slot is for the transmission of the recovery information.

[0144] Figure 16 A communication device 1600 is illustrated that may include various components (e.g., corresponding to apparatus - plus - function components) configured to perform operations for the techniques disclosed herein, such as Figure 9 the operations described in. The communication device 1600 includes a processing system 1602 coupled to a transceiver 1608. The transceiver 1608 is configured to transmit and receive signals for the communication device 1600 (such as the various signals described herein) via an antenna 1610. The processing system 1602 may be configured to perform processing functions for the communication device 1600, including processing signals received and / or to be transmitted by the communication device 1600.

[0145] The processing system 1602 includes a processor 1604 coupled to a computer - readable medium / memory 1612 via a bus 1606. In some aspects, the computer - readable medium / memory 1612 is configured to store instructions (e.g., computer - executable code) that, when executed by the processor 1604, cause the processor 1604 to perform Figure 9The operations illustrated in [description] or other operations for performing various techniques discussed herein for recovering, e.g., side - link communications that are received by a wireless node with errors or missed due to the wireless node transmitting while side - link communications are occurring. In some aspects, the computer - readable medium / memory 1612 stores: code 1614 for communicating side - link communications with a second UE; code 1616 for receiving recovery information in a recovery time slot, where the recovery information is for recovering at least one of the side - link communications of one or more third UEs transmitted when the side - link communication occurred, and where the recovery time slot is for the transmission of the recovery information; and code 1618 for determining another side - link communication transmitted by the wireless node based on the side - link communication and the recovery information. In some aspects, the processor 1604 has circuitry configured to implement the code stored in the computer - readable medium / memory 1612. The processor 1604 includes: circuitry 1620 for communicating side - link communications with a first UE; circuitry 1622 for receiving recovery information in a recovery time slot, where the recovery information is for recovering at least one of the side - link communications of one or more second UEs transmitted when the side - link communication occurred, and where the recovery time slot is for the transmission of the recovery information; and circuitry 1624 for determining another side - link communication transmitted by the wireless node based on the side - link communication and the recovery information.

[0146] Example aspects

[0147] In addition to the aspects described above, aspects of specific combinations are also within the scope of the present disclosure, some of which are described in detail below:

[0148] Aspect 1: A method for wireless communication by a wireless node, comprising: receiving a plurality of side - link communications, each side - link communication being between two user equipments (UEs); and transmitting recovery information in a recovery time slot, where the recovery information is for recovering at least one of the side - link communications of the two UEs or other UEs transmitted when at least one of the side - link communications occurred, and where the recovery time slot is for the transmission of at least the recovery information.

[0149] Aspect 2: The method according to aspect 1, wherein the recovery information includes parity information for the side - link communication, and the method further comprises generating the parity information.

[0150] Aspect 3: The method according to aspect 2, wherein generating the parity information includes using a maximum - distance - separable (MDS) code to generate the parity information.

[0151] Aspect 4: The method according to any one of aspects 1 - 3, wherein each of the side - link communications is in a sub - channel of a frequency band.

[0152] Aspect 5: The method according to aspect 4, wherein transmitting the recovery information includes transmitting the recovery information in the subchannel.

[0153] Aspect 6: The method according to any one of aspects 1-5, wherein each of the sidelink communications includes first-phase sidelink control information (SCI-1).

[0154] Aspect 7: The method according to any one of aspects 1-5, wherein each of the sidelink communications includes first-phase sidelink control information (SCI-1), wherein the sidelink communications are in a plurality of subchannels of a frequency band, and wherein transmitting the recovery information includes transmitting the recovery information in one subchannel of the frequency band.

[0155] Aspect 8: The method according to any one of aspects 1-5, wherein each of the sidelink communications includes a physical shared sidelink channel (PSSCH) and the method further comprises: clustering transport blocks (TBs) of the sidelink communication into TB groups; encoding the TBs in the group using a maximum distance separable (MDS) code to generate the recovery information; and encoding the encoded group using a low density parity check (LDPC) code to generate recovery information.

[0156] Aspect 9: The method according to aspect 8, wherein a cyclic redundancy check (CRC) is included in each of the TBs of the TB.

[0157] Aspect 10: The method according to any one of aspects 8 or 9, further comprising combining cyclic redundancy checks (CRCs) from each of the TBs of the TB.

[0158] Aspect 11: The method according to any one of aspects 8 or 9, further comprising: removing cyclic redundancy checks (CRCs) from each of the TBs of the TB; and generating a new CRC for the combination of the TBs.

[0159] Aspect 12: The method according to any one of aspects 8-11, wherein clustering the TBs includes clustering one TB of one sidelink communication from each of a plurality of time slots, wherein at least one of the sidelink communications occurs in each of the plurality of time slots.

[0160] Aspect 13: The method according to any one of aspects 8-12, wherein clustering the TBs is based on the size of each of the TBs of the TB.

[0161] Aspect 14: The method according to any one of aspects 8-13, wherein clustering the TBs includes adding zero padding to at least one of the TBs of the TB.

[0162] Aspect 15: The method according to any one of aspects 8-14, wherein clustering the TBs is based on a layer one (L1) destination identifier (ID) of each TB in the TBs.

[0163] Aspect 16: The method according to any one of aspects 8-15, wherein clustering the TBs is based on sub-channels of a frequency band in which sidelink communication is transmitted.

[0164] Aspect 17: The method according to any one of aspects 8-16, wherein clustering the TBs is based on the priority of each of the sidelink communications, and wherein TBs of high-priority sidelink communications are excluded from the cluster.

[0165] Aspect 18: The method according to any one of aspects 8-17, wherein clustering the TBs is based on an indication in a signal.

[0166] Aspect 19: The method as described in aspect 18, wherein the signal includes second-phase sidelink control information (SCI-2).

[0167] Aspect 20: The method as described in aspect 18, wherein the signal includes a media access control control element (MAC-CE).

[0168] Aspect 21: The method according to any one of aspects 1-20, further comprising: selecting the plurality of sidelink communications based on at least one of the priority of each sidelink communication, the remaining amount of time in a packet delay budget (PDB), the cyclic redundancy check (CRC) pass status of each sidelink communication, or the transport block size (TBS) of each sidelink communication.

[0169] Aspect 22: The method according to any one of aspects 1-5 or aspect 21, wherein each of the sidelink communications includes a physical shared sidelink channel (PSSCH) and the method further comprises: clustering transport blocks (TBs) of the sidelink communications into TB groups; encoding each TB in the group using a low-density parity-check (LDPC) code to generate an LDPC-encoded TB group; and encoding each LDPC-encoded TB group using a maximum distance separable (MDS) code to generate the recovery information.

[0170] Aspect 23: The method as described in aspect 22, wherein encoding each TB in the group using an LDPC code includes encoding a redundancy version (RV) 0 of each TB in the group.

[0171] Aspect 24: The method according to any one of aspects 1-5 or aspect 21, wherein each of the sidelink communications comprises a Physical Shared Sidelink Channel (PSSCH) and is in a plurality of time slots, and wherein the recovery information comprises parity information, and the method further comprises: concatenating transport blocks (TBs) of one or more of the sidelink communications to form a TB group for each corresponding time slot, the one or more of the sidelink communications being in one of the plurality of time slots; padding each of the groups to form padded groups, wherein each padded group has the same size; and generating the parity information based on the padded groups.

[0172] Aspect 25: The method according to any one of aspects 1-5 or aspect 21, wherein each of the sidelink communications comprises second stage sidelink control information (SCI-2) and the method further comprises: batching the payloads of the SCI-2 into payload groups; encoding the payloads in the groups using a Maximum Distance Separable (MDS) code to generate encoded groups; and encoding the encoded groups using a polar code to generate the recovery information.

[0173] Aspect 26: The method according to any one of aspects 1-5 or aspect 21, wherein each of the sidelink communications comprises second stage sidelink control information (SCI-2) and the method further comprises: batching the payloads of the SCI-2 into payload groups; encoding each of the payloads in the groups using a polar code to generate polar encoded payload groups; and encoding each polar encoded payload group using a Maximum Distance Separable (MDS) code to generate the recovery information.

[0174] Aspect 27: The method according to any one of aspects 1-5 or aspect 21, wherein the plurality of sidelink communications are received in a time slot, and wherein the recovery information comprises replicas of the plurality of sidelink communications.

[0175] Aspect 28: The method as described in aspect 27, further comprising selecting the time slot based on at least one of the number of high priority transmissions in the time slot, the number of UEs affected by missing the plurality of sidelink communications, the remaining number of retransmissions for the TB in the time slot, or the proximity of the UE transmitting one of the sidelink communications.

[0176] Aspect 29: The method according to any one of aspects 1-28, wherein the wireless node comprises a Road Side Unit (RSU).

[0177] Aspect 30: The method according to any one of aspects 1-28, wherein the wireless node comprises a group leader for sidelink communications.

[0178] Aspect 31: The method according to any one of aspects 1 - 28, wherein the wireless node comprises a UE that reserves transmission resources in the recovery time slot.

[0179] Aspect 32: The method according to any one of aspects 1 - 31, further comprising combining a plurality of first - stage sidelink control information (SCI - 1) messages in the sidelink communication, wherein the recovery information comprises the combined plurality of SCI - 1 messages.

[0180] Aspect 33: A method for wireless communication by a user equipment (UE), comprising: transmitting sidelink communication to another UE; receiving recovery information in a recovery time slot, wherein the recovery information is for recovering at least one of the sidelink communications of other UEs transmitted when the sidelink communication occurred, and wherein the recovery time slot is for the transmission of the recovery information; and determining another sidelink communication transmitted by the wireless node based on the sidelink communication and the recovery information.

[0181] Aspect 34: An apparatus comprising means for performing the method according to any one of aspects 1 to 33.

[0182] Aspect 35: An apparatus comprising: at least one processor and a memory coupled to the at least one processor, the memory comprising code that can be executed by the at least one processor to cause the apparatus to perform the method as described in any one of aspects 1 to 33.

[0183] Aspect 36: A computer - readable medium having stored thereon computer - executable code for wireless communication, the computer - executable code when executed by at least one processor causing an apparatus to perform the method as described in any one of aspects 1 to 33.

[0184] The methods disclosed herein include one or more steps or actions for implementing the method. These method steps and / or actions can be interchanged with each other 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 the specific steps and / or actions can be altered without departing from the scope of the claims.

[0185] As used herein, the phrase "at least one of" recited in a list of items refers to any combination of those items, including a single member. As an example, "at least one of a, b, or c" is intended to cover: a, b, c, a - b, a - c, b - c, and a - b - c, as well as any combination having multiple identical elements (e.g., a - a, a - a - a, a - a - b, a - a - c, a - b - b, a - c - c, b - b, b - b - b, b - b - c, c - c, and c - c - c, or any other ordering of a, b, and c).

[0186] As used herein, the term "determine" encompasses a variety of actions. For example, "determine" can include computing, calculating, processing, deriving, researching, looking up (e.g., looking up in a table, database, or other data structure), ascertaining, and the like. Moreover, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Moreover, "determine" can include parsing, selecting, choosing, establishing, and the like.

[0187] The foregoing description is provided to enable any person 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 generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein but are to be accorded the full scope consistent with the language of the claims, wherein the recitation of a single element is not intended to mean "one and only one" (unless specifically so stated) but "one or more." Unless specifically stated otherwise, the term "some / a" means one or more. All structural and functional equivalents known to those of ordinary skill in the art currently or hereafter are expressly incorporated herein by reference and are intended to be covered by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the claims. No element of a claim should be construed under the provisions of 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is recited using the phrase "step for."

[0188] The various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. These means can include a variety of hardware and / or software components and / or modules, including but not limited to circuitry, application specific integrated circuits (ASICs), or processors. In general, where there are operations illustrated in the figures, these operations can have corresponding paired apparatus plus function components. For example, Figure 8 the various operations shown in and -9 can be performed by Figure 4 the various processors shown in, such as processors 466, 458, 464, and / or the controller / processor 480 of UE 120a.

[0189] The various illustrative logical blocks, modules, and circuits described in connection with the present disclosure may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a 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. A general-purpose processor may be a microprocessor, but in the alternative, 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, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0190] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented with a bus architecture. Depending on the particular application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, etc. to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of user terminal 120 (see Figure 1 ), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link together various other circuits such as a timing source, peripherals, voltage regulators, power management circuits, and similar circuits, which are well known in the art and will not be described further herein. The processor may be implemented with one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry capable of executing software. Depending on the particular application and overall design constraints imposed on the overall system, those of ordinary skill in the art will recognize how best to implement the functionality described with respect to the processing system.

[0191] If implemented in software, each function may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Software should be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The computer-readable medium includes both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. The computer-readable storage medium may be coupled to the processor such that the processor can read from and write to the storage medium. In an alternative, the storage medium may be integrated into the processor. By way of example, the machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium separate from a wireless node on which instructions are stored, all of which may be accessed by the processor via a bus interface. Alternatively or additionally, the machine-readable medium or any part thereof may be integrated into the processor, such as may be the case with a cache and / or a general register file. By way of example, examples of the machine-readable medium may include 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, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable medium may be embodied in a computer program product.

[0192] Software modules may include a single instruction or many instructions and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable medium may include several software modules. These software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. These software modules may include a transmission module and a reception module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, when a triggering event occurs, the software module may be loaded from a hard drive into RAM. During the execution of the software module, the processor may load some instructions into the cache to improve access speed. One or more cache lines may then be loaded into the general register file for the processor to execute. When referring to the functionality of a software module hereinafter, it will be understood that such functionality is implemented by the processor when the processor executes instructions from the software module.

[0193] Similarly, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technology such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology such as infrared, radio, and microwave is included in the definition of the medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and disc, where disk often magnetically reproduces data, while disc optically reproduces data with a laser. Thus, in some aspects, a computer-readable medium may include a non-transitory computer-readable medium (e.g., a tangible medium). Additionally, for other aspects, a computer-readable medium may include a transitory computer-readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0194] Accordingly, certain aspects may include a computer program product for performing the operations given herein. For example, such a computer program product may include a computer-readable medium having instructions stored (and / or encoded) thereon that can be executed by one or more processors to perform the operations described herein. For example, instructions for performing the operations described and illustrated in Figures 8-9 are provided.

[0195] Furthermore, it should be appreciated that modules and / or other suitable means for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by a user terminal and / or a base station, where applicable. For example, such devices can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.) such that once the storage device is coupled to or provided to the user terminal and / or base station, the device can obtain the various methods. Additionally, any other suitable technology can be utilized that is adapted to provide the methods and techniques described herein to a device.

[0196] It will be understood that the claims are not limited to the exact configurations and components described above. Various changes, substitutions, and modifications can be made in the arrangement, operation, and details of the methods and apparatuses described above without departing from the scope of the claims.

Claims

1. A device for wireless communication, comprising: a receiver configured to receive a plurality of sidelink communications from a plurality of user equipments (UEs); a memory; a processor coupled to the memory, the processor and the memory being configured to: cluster payloads associated with the sidelink communications into payload groups, wherein at least one of the payloads includes sidelink control information (SCI); and generate recovery information based on the payload groups; and a transmitter configured to transmit the recovery information in a recovery time slot, wherein the recovery information is used to recover the payloads associated with the sidelink communications, and wherein the recovery time slot is used for transmission of at least the recovery information.

2. The device according to claim 1, wherein: the processor and the memory are configured to generate parity check information for the sidelink communications, wherein the recovery information includes the parity check information.

3. The device according to claim 2, wherein the processor and the memory are configured to generate the parity check information using an erasure code.

4. The device according to claim 1, wherein the transmitter is configured to transmit the recovery information in a subchannel of a frequency band, and each of the sidelink communications is in the subchannel.

5. The device according to claim 1, wherein: the sidelink control information includes first-phase sidelink control information (SCI-1), the sidelink communications are in a plurality of subchannels of a frequency band, and the transmitter is configured to transmit the recovery information in at least one of the subchannels of the frequency band.

6. The device according to claim 1, wherein: the processor and the memory are configured to: cluster transport blocks (TBs) of the sidelink communications into TB groups; encode the TBs in the TB groups using an erasure code to generate the recovery information; and encode the recovery information using a low-density parity-check (LDPC) code, wherein each of the sidelink communications includes a physical shared sidelink channel (PSSCH).

7. The device according to claim 6, wherein a cyclic redundancy check (CRC) is included in each of the TBs.

8. The device according to claim 6, wherein the processor and the memory are configured to combine cyclic redundancy checks (CRC) from each of the TBs.

9. The device according to claim 6, wherein the processor and the memory are configured to: remove cyclic redundancy checks (CRC) from each of the TBs; and generate a new CRC for the combination of the TBs.

10. The device according to claim 6, wherein the processor and the memory are configured to cluster one TB of one sidelink communication from each of a plurality of time slots, wherein at least one of the sidelink communications occurs in each of the plurality of time slots.

11. The device according to claim 1, wherein: The processor and the memory are configured to select the plurality of sidelink communications based on at least one of the priority of each sidelink communication, the remaining amount of time in the packet delay budget PDB, the cyclic redundancy check CRC pass status of each sidelink communication, or the transport block size TBS of each sidelink communication.

12. The apparatus according to claim 1, wherein: The processor and the memory are configured to: Cluster the transport blocks TB of the sidelink communication into a first TB cluster; Encode each TB in the first TB cluster using a low density parity check LDPC code to generate a second TB cluster of LDPC-encoded TBs; And Encode each TB in the second TB cluster of LDPC-encoded TBs using an erasure code to generate the recovery information, wherein each of the sidelink communications includes a physical shared sidelink channel PSSCH.

13. The apparatus according to claim 12, wherein the processor and the memory are configured to encode each TB in the first TB cluster using the LDPC code together with redundancy version RV0.

14. The apparatus according to claim 1, wherein: The processor and the memory are configured to: Concatenate the transport blocks TB of one or more of the sidelink communications to form a TB cluster for each corresponding time slot, wherein one or more of the sidelink communications are in one of a plurality of time slots, and wherein the sidelink communications are in the plurality of time slots; Pad each of the TB clusters to form a padded cluster, wherein each of the padded clusters has the same size; And Generate parity check information for the recovery information based on the padded clusters, wherein each of the sidelink communications includes a physical shared sidelink channel PSSCH.

15. The apparatus according to claim 1, wherein: The sidelink communication includes a first payload in the first stage sidelink control information SCI-1 and a second payload in the second stage sidelink control information SCI-2; And For clustering the payloads and generating the recovery information; The processor and the memory are further configured to: Cluster the second payload in the SCI-2 into at least a part of the payload cluster; Encode the payloads in the payload cluster using an erasure code to generate an encoded cluster, and Encode the encoded cluster using a polar code to generate the recovery information.

16. The apparatus according to claim 1, wherein: The sidelink communication includes a first payload in the first stage sidelink control information SCI-1 and a second payload in the second stage sidelink control information SCI-2; And For clustering the payloads and generating the recovery information; The processor and the memory are further configured to: Cluster the second payload in the SCI-2 into at least a part of the payload cluster; Use a polar code to encode each of the payloads in the payload group to generate a polar-encoded payload group; and Use an erasure code to encode each polar-encoded payload group to generate the recovery information.

17. The apparatus according to claim 1, wherein the plurality of sidelink communications are received in a time slot, and wherein the recovery information includes a copy of the plurality of sidelink communications.

18. The apparatus according to claim 17, wherein the processor and the memory are configured to select the time slot based on at least one of the number of high-priority transmissions in the time slot, the number of UEs affected by missing the plurality of sidelink communications, the remaining number of retransmissions for the TB in the time slot, or the proximity of the UE transmitting one of the sidelink communications.

19. The apparatus according to claim 1, wherein for grouping the payloads, the processor and the memory are configured to combine a plurality of first-stage sidelink control information SCI-1 messages received in the sidelink communication, wherein the payload group includes the combined plurality of SCI-1 messages.

20. An apparatus for wireless communication, comprising: a transceiver configured to: communicate sidelink communications with a first UE, and receive recovery information in a recovery time slot, wherein the recovery information is used to recover at least one sidelink communication of one or more second UEs transmitted when the sidelink communication occurred, and wherein the recovery time slot is for the transmission of the recovery information, and wherein the sidelink communication includes sidelink control information; a memory; and a processor coupled to the memory, the processor and the memory being configured to determine another sidelink communication transmitted by a wireless node based on the sidelink communication and the recovery information; and decode the another sidelink communication using the erasure code at least in part based on the recovery information including a payload group encoded with the erasure code for the sidelink control information.

21. The apparatus according to claim 20, wherein the recovery information further includes parity check information.

22. The apparatus according to claim 20, wherein the recovery information further includes a group of transport blocks encoded with the erasure code.

23. A method for wireless communication by a wireless node, comprising: receiving a plurality of sidelink communications from a plurality of user equipments (UEs); and grouping payloads associated with the sidelink communications into a payload group, wherein at least one of the payloads includes sidelink control information (SCI); and generating recovery information based on the payload group; and transmitting the recovery information in a recovery time slot, wherein the recovery information is used to recover the payloads associated with the sidelink communications, and wherein the recovery time slot is for the transmission of at least the recovery information.

24. The method according to claim 23, wherein the recovery information includes parity check information for the sidelink communications, and the method further includes generating the parity check information using the erasure code.

25. The method according to claim 23, wherein the sidelink control information includes first-phase sidelink control information SCI-1, wherein the sidelink communication is in a plurality of subchannels of a frequency band, and wherein transmitting the recovery information includes transmitting the recovery information in one subchannel of the frequency band.

26. The method according to claim 23, wherein each of the sidelink communications includes a physical shared sidelink channel PSSCH and the method further comprises: grouping transport blocks TB of the sidelink communication into TB groups; encoding the TBs in the TB groups using an erasure code to generate the recovery information, and encoding the recovery information using a low-density parity-check LDPC code.

27. A method for wireless communication by a first user equipment UE, comprising: communicating a sidelink communication with a second UE; receiving recovery information in a recovery time slot, wherein the recovery information is for recovering at least one sidelink communication of one or more third UEs transmitted when the sidelink communication occurred, wherein the recovery time slot is for transmission of the recovery information, and wherein the sidelink communication includes sidelink control information; and determining another sidelink communication transmitted by a wireless node based on the sidelink communication and the recovery information; and decoding the another sidelink communication using the erasure code at least in part based on the recovery information including a payload group for the sidelink control information encoded with the erasure code.

28. The method according to claim 27, wherein the recovery information further includes parity check information.

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