WO2022032612A1

WO2022032612A1 - Network coding for control channels

Info

Publication number: WO2022032612A1
Application number: PCT/CN2020/109067
Authority: WO
Inventors: Liangming WU; Changlong Xu; Gabi Sarkis; Kangqi LIU; Jian Li; Ruiming Zheng
Original assignee: Qualcomm Incorporated
Priority date: 2020-08-14
Filing date: 2020-08-14
Publication date: 2022-02-17

Abstract

Methods, systems, and devices for wireless communications, and more specifically to sidelink communications are described. A communication device, otherwise, knowns as a user equipment (UE) may determine first sidelink control information (SCI) associated with the sidelink communications. The first SCI may include an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The UE may code the first SCI based on a rateless code, and transmit the rateless coded first SCI on a physical sidelink control channel (PSCCH). The UE may determine the second SCI associated with the sidelink communications based on the first coded SCI, and code the second SCI based on the rateless code. The UE may transmit the rateless coded second SCI on a physical sidelink shared channel (PSSCH).

Description

NETWORK CODING FOR CONTROL CHANNELS

FIELD OF TECHNOLOGY

The following relates to wireless communications, and more specifically to sidelink communications and network coding for sidelink channels.

BACKGROUND

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) .

A wireless communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) . The wireless communications system may support wireless communications between a base station and a UE over an access link (e.g., a Uu interface) . The base station and the UE may communicate downlink and uplink information (e.g., control information, data) over the access link. The wireless communications system may also support device-to-device (D2D) communications (also referred to as sidelink communications) between multiple UEs over a sidelink (e.g., a PC5 interface) . Because the UEs operate in a half duplex mode as part of sidelink communications, the UEs may be unable to simultaneously transmit to, and receive from, other UEs sidelink communications. As a result, the half duplex mode may impact a reliability or a latency of the sidelink communications.

SUMMARY

Various aspects of the described techniques relate to configuring a communication device, which may be a user equipment (UE) to support improvements to sidelink control information (SCI) transmission and reception. For example, to improve a reliability or reduce a latency of SCI transmission and reception, the UE may be configured to rateless code SCI. The exchange of SCI may occur in two stages. At a first stage, the UE may transmit first sidelink control information (SCI-1) on a physical sidelink control channel (PSCCH) , while at a second stage the UE may transmit second sidelink control information (SCI-2) . In some examples, the UE may be configured to rateless code SCI-1. In some other examples, the UE may be configured to rateless code both SCI-1 and SCI-2, but separately. In other examples, the UE may be configured to combine SCI-1 and SCI-2 and rateless code the combined SCI. The UE may be preconfigured with sidelink resources to use for the rateless coded SCI. Additionally, the UE may be configured to signal to other UEs resource usage for the rateless coded SCI. By rateless coding SCI (e.g., SCI-1, SCI-2) , the UE may experience power saving. The described techniques may, as a result, also include features for improvements to sidelink operations and, in some examples, may promote high reliability and low latency sidelink communications, among other benefits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGs. 1 and 2 illustrate examples of wireless communications systems that support network coding for control channels in accordance with aspects of the present disclosure.

FIGs. 3A and 3B illustrate examples of sidelink resource configurations that support network coding for control channels in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a process flow that supports network coding for control channels in accordance with aspects of the present disclosure.

FIGs. 5 and 6 show block diagrams of devices that support network coding for control channels in accordance with aspects of the present disclosure.

FIG. 7 shows a block diagram of a communications manager that supports network coding for control channels in accordance with aspects of the present disclosure.

FIG. 8 shows a diagram of a system including a device that supports network coding for control channels in accordance with aspects of the present disclosure.

FIGs. 9 through 13 show flowcharts illustrating methods that support network coding for control channels in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

A wireless communications system may include communication devices, such as a user equipment (UE) and a base station (e.g., an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB, either of which may be referred to as a gNB, or some other base station) , that support wireless communications over one or multiple radio access technologies. Examples of radio access technologies include fourth generation (4G) systems, such as Long Term Evolution (LTE) systems, and fifth generation (5G) systems, which may be referred to as new radio (NR) systems. Wireless communications between a UE and a base station, in the wireless communications system, for example, may occur over a communication link referred to as an access link (e.g., a Uu interface) . The wireless communications system may additionally, or alternatively, support sidelink communications between multiple UEs. Examples of sidelink communications may include, but are not limited to, device-to-device (D2D) communications, vehicle-based communications, which may also be referred to as vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, cellular V2X (C-V2X) communications, and the like. Sidelink communications between UEs, in the wireless communications system, for example, may occur over a communication link referred to as a sidelink (e.g., a PC5 interface) .

A UE may exchange sidelink control information (SCI) , which carries information the UE may use in order to be able to receive and decode sidelink data from another UE. When supporting sidelink communications, the UE may operate in a half duplex mode, in which the UE may transmit to, or receive from, another UE sidelink information (e.g., SCI, sidelink data) . Because the UE operates in the half duplex mode, the UE might be unable to at the same time transmit to, and receive from, the other UE sidelink information (e.g., SCI, sidelink data) . As a result, the half duplex mode may impact a reliability or a latency of sidelink information exchange between the UEs. Various aspects of the described techniques relate to configuring a UE to support improvements to sidelink information transmission and reception. For example, to improve a reliability or reduce a latency of sidelink information transmission and reception, the UE may be configured to rateless code SCI.

A rateless code may be a fountain code (also referred to as a network code, because the UE may apply the network code in a network layer of a protocol stack associated with the UE) . A fountain code is rateless because a number of encoded packets (e.g., carrying sidelink information) that can be generated from a source message (e.g., an SCI message) is potentially limitless, and the number of encoded packets generated can be determined on-demand. A packet carrying sidelink information (e.g., SCI-1, SCI-2) can thereby be recovered by another UE as long as a number of received packets is greater than a threshold (e.g., a source packet) and irrespective of which packets are received at the other UE. Fountain codes may include Luby transform (LT) codes, Raptor codes, and the like.

The UE may exchange SCI in two stages. At a first stage, the UE may transmit first sidelink control information (SCI-1) on a physical sidelink control channel (PSCCH) , while at a second stage the UE may transmit second sidelink control information (SCI-2) . In some examples, the UE may be configured to rateless code SCI-1. In some other examples, the UE may be configured to rateless code both SCI-1 and SCI-2, but separately. In other examples, the UE may be configured to aggregate SCI-1 and SCI-2 and rateless code the aggregated SCI. The UE may be preconfigured with sidelink resources to use for the rateless coded SCI. Additionally, the UE may be configured to signal to another UE resource usage for the rateless coded SCI.

Particular aspects of the subject matter described in this disclosure may be implanted to realize one or more of the following potential advantages. The techniques employed by a UE may provide benefits and enhancements to the operation of the UE. For example, operations performed by the UE may provide improvements to sidelink operations. In some examples, the UE may support power saving, among other examples, by rateless coding sidelink communications. By way of example, the UE may rateless code SCI (e.g., SCI-1, SCI-2) . The rateless coded SCI may be used for efficient transmission and reception of SCI, and thereby the UE may experience power saving. The UE may thus include features for improvements to power consumption, spectral efficiency, higher data rates and, in some examples, may promote enhanced efficiency for high reliability and low latency sidelink operations, among other benefits.

Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are then described with reference to sidelink resource configurations and process flow related to techniques for rateless coding SCI. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to techniques for rateless coding SCI.

FIG. 1 illustrates an example of a wireless communications system 100 that supports network coding for control channels in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment) , as shown in FIG. 1.

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) . The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both. In some examples, the backhaul links 120 may be or include one or more wireless links. One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) and may be positioned according to a channel raster for discovery by the UEs 115. A carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs 115 via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology) .

The communication links 125 shown in the wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode) . A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz) ) . Devices of the wireless communications system 100 (e.g., the base stations 105, the UEs 115, or both) may have hardware configurations that support communications over a particular carrier bandwidth or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 or UEs 115 that support simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured for operating over portions (e.g., a sub-band, a BWP) or all of a carrier bandwidth.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

One or more numerologies for a carrier may be supported, where a numerology may include a subcarrier spacing (Δ? ) and a cyclic prefix. A carrier may be divided into one or more BWPs having the same or different numerologies. In some examples, a UE 115 may be configured with multiple BWPs. In some examples, a single BWP for a carrier may be active at a given time and communications for the UE 115 may be restricted to one or more active BWPs. The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s=1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N _f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation. A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET) ) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) . In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) . A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.

A base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timings, and transmissions from different base stations 105 may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations. Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for the UEs 115 include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to narrowband communications) , or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs) ) within a carrier, within a guard-band of a carrier, or outside of a carrier.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol) . One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

In some systems, the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115) . In some examples, vehicles may communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communications, or with both.

In the wireless communications system 100, a UE 115 may exchange SCI with another UE 115. The UE 115 may operate in a half duplex mode, in which the UE 115 may transmit to, or receive from, another UE 115 sidelink information (e.g., SCI, sidelink data) . Because the UE 115 functions in the half duplex mode, the UE 115 is unable to concurrently transmit to, and receive from, the other UE 115 sidelink information (e.g., SCI, sidelink data) . As a result, the half duplex mode may effect a reliability or a latency of sidelink information exchange between the UEs 115. Various aspects of the described techniques relate to configuring a UE 115 to support improvements to sidelink information transmission and reception by encoding SCI (e.g., SCI-1 or SCI-2, or both) using a rateless code. In some cases, the wireless communications system 100, may use an anchor node (e.g., a base station 105) or relay node (e.g., a relay UE 115) to receive multiple SCI and retransmit via network coding to improve the SCI robustness. As described herein, a rateless code may be a fountain code (also referred to as a network code) . In some examples, the UE 115 may encode SCI using an LT code. In some other examples, the UE 115 may encode SCI using a Raptor code. In other examples, the UE 115 may encode SCI using another rateless code.

The wireless communications system 100 may support rateless codes. By way of example, a message may have a size of K bits and source data can be decoded from any set of encoded packets K` based on K` satisfying a threshold (e.g., K` greater than K) . By way of example, an SCI message (e.g., SCI-1 or SCI-2, or both) may have a size of K packets s ₁, s ₂, ..., s _K. A transmitted UE 115 may generate K random bits (G _kj) and transmit a packet p _j. The transmitted packet p _j may be set to a bitwise sum of the source packets for which G _kj is 1, and defined by Equation (1) . This sum can be done by successively exclusive-or-ing the packets together. Each set of K random bits may be defined as a column in a binary generator matrix.

A receiver UE 115 may receive and decode the SCI message by recovering all or a portion of the transmitted packets p _j by the transmitter UE 115. In some examples, the receiver UE 115 may determine a portion of the generator matrix G referred to hereby as G′. For example, the receiver UE 115 may determine the generator matrix G based on a random-number generator. In some other examples, the transmitter UE 115 may select a random key k _n, given which the K bits G _kn are determined by a pseudo-random procedure. The transmitter UE 115 may transmit the random key k _n in a header of the transmitted packets p _j. As long as the packet size is greater than the random key size, this random key introduces a small overhead cost for the transmitter UE 15.

The receiver UE 115 may receive a number of encoded packets K’ and may determine that the number of received packets is less than the size of K bits of the SCI message. Otherwise, the receiver UE 115 may receive and recover packets d _k according to the following Equation (2) .

For example, the receiver UE 115 may invert the generator matrix G to recover the packets d _k. G _nk may be invertible with a minimum N. Alternatively, the receiver UE 115 may recover the packets d _k based on the rank of the generator matrix G being equal to K.

A UE 115 may, in some examples, encode sidelink information (e.g., SCI-1 or SCI-2, or both) packets using an LT code. The UE 115 may encode the packets using a source message (e.g., a SCI message) by randomly selecting a degree d _n of the packet from a degree distribution ρ (d) . In some examples, the degree distribution ρ (d) may be based on a size of the source message. The UE 115 may randomly select d _n distinct input packets. This encoding may define a graph connecting encoded sidelink information packets to the source message. To avoid redundancy, the UE 115 may determine a solution distribution defined by Equations (3) and (4)

ρ (1) =1/K (3)

The robust soliton distribution may have additional parameters, c and d to ensure that the expected number of degree-one checks as defined by Equation (5) .

The parameter d is a bound on the probability that the decoding fails to run to completion after a certain number K’ of packets have been received. The parameter c is a constant of order 1 (or a free parameter) . The UE 115 may define a positive function as defined by Equation (6) .

The UE 115 may thereby determine a solution distribution ρ to τ and normalize to obtain a robust solution distribution μ as defined by Equation (7) .

where Z is equal to ∑ _dρ (d) +τ (d) . The number of encoded packets needed at the receiver UE 15 to ensure that the decoding can run to completion with probability at least 1-δ, is K’=KZ.

An input packet for rateless coding may be fixed or known at both the transmitter UE 115 and the receiver UE 115. However, SCI with rateless coding may be associated with one or more factors, which may impact the rateless coded SCI packets. For example, multiple SCI packet types may be possible (e.g., SCI-1 and SCI-2) . Additionally, latency of a parity (or network coded) packet may have to satisfy a threshold. Alternatively or additionally, a total number of SCI packets (or source symbol for rateless coding) may be unable to be predicted. A UE 115 may, therefore, be configured to support improvements to SCI transmission and reception by considering the above factors. For example, the UE 115 may be configured to rateless code SCI-1 and not rateless code SCI-2. In some other examples, the UE 115 may be configured to rateless code both SCI-1 and SCI-2, but separately. In other examples, the UE 115 may be configured to combine SCI-1 and SCI-2 and rateless code the combined SCI. The UE 115 may be preconfigured with sidelink resources to use for the rateless coded SCI. Additionally, the UE 115 may be configured to signal to other UEs 115 resource usage for the rateless coded SCI. By rateless coding SCI (e.g., SCI-1, SCI-2) , the UE 115 may experience power saving. The described techniques may, as a result, also include features for improvements to sidelink operations and, in some examples, may promote high reliability and low latency sidelink communications, among other benefits.

In the wireless communications system 100, a UE 115 may determine a resource allocation for sidelink communications. The resource allocation may be defined in units of sub-channels in a frequency domain and slots in a time domain. In some examples, the resource allocation may be reservation-based for the sidelink communications. In other words, the UE 115 may reserve resources for sidelink communications to avoid interference to other UEs 115. For example, a UE 115 may reserve resources in a current slot and one or more upcoming slots (e.g., up to two upcoming slots) . The reservation information may be carried in SCI. Reservation of resources may, in some examples, span 32 logical slots. The reserved resources may be periodic or aperiodic. In some examples, reserved periodic resources may be configurable with a period having a value between 0 ms and 1000 ms, which may be signaled in SCI. In some examples, periodic resource reservation and signaling may be disabled via preconfiguration.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The network operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) . Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .

The wireless communications system 100 may operate using one or more frequency bands, in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . The region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

The wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, the wireless communications system 100 may support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

The base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords) . Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) , where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

A base station 105 or a UE 115 may use beam sweeping techniques as part of beam forming operations. For example, a base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions. For example, the base station 105 may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station 105, or by a receiving device, such as a UE 115) a beam direction for later transmission or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted in one or more beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions and may report to the base station 105 an indication of the signal that the UE 115 received with a highest signal quality or an otherwise acceptable signal quality.

In some examples, transmissions by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station 105 to a UE 115) . The UE 115 may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across a system bandwidth or one or more sub-bands. The base station 105 may transmit a reference signal (e.g., a cell-specific reference signal (CRS) , a channel state information reference signal (CSI-RS) ) , which may be precoded or unprecoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook) . Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) or for transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

A receiving device (e.g., a UE 115) may try multiple receive configurations (e.g., directional listening) when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions. In some examples, a receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal) . The single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio (SNR) , or otherwise acceptable signal quality based on listening according to multiple beam directions) .

The wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

The UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions) . In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

FIG. 2 illustrates an example of a wireless communications system 200 that supports network coding for control channels in accordance with aspects of the present disclosure. The wireless communications system 200 may implement aspects of the wireless communications system 100. For example, the wireless communications system 200 may include a base station 105-a and UEs 115-a, 115-b, which may be examples of a base station 105 and a UE 115 as described with reference to FIG. 1. The wireless communications system 200 may support multiple radio access technologies including 4G systems such as LTE systems, LTE-A systems, or LTE-A Pro systems, and 5G systems which may be referred to as NR systems. The wireless communications system 200 may include features for improvements to power savings and, in some examples, may promote high reliability and low latency sidelink communications, among other benefits.

In the example of FIG. 2, the base station 105-a may provide a coverage area 110-a over which the base station 105-a and the UEs 115-a, 115-b may establish one or more communication links 205, which may correspond to an access link (e.g., a Uu link, a Uu interface) for wireless communications. The coverage area 110-a may be an example of a geographic area over which the base station 105-a and the UEs 115-a, 115-b may support exchange of information (e.g., control information, data) according to one or more radio access technologies. The base station 105-a may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The coverage area 110-a may, for example, correspond to one or more cells.

The UEs 115-a, 115-b may also support sidelink communications. For example, the UE 115-a and the UE 115-b may establish a communication link 210, which may correspond to a sidelink (e.g., a PC5 link, a PC5 interface) . In some examples, the UE 115-a may exchange SCI with the UE 115-b. The SCI carries information the UE 115-b may use in order to be able to receive and decode sidelink data from the UE 115-a. In some other examples, the UE 115-b may exchange SCI with the UE 115-b. Here, the SCI carries information the UE 115-a may use in order to be able to receive and decode sidelink data from the UE 115-b. When supporting sidelink communications, the UEs 115-a, 115-b may operate in a half duplex mode, in which the UEs 115-a, 115-b may transmit to, or receive from, sidelink information (e.g., SCI, sidelink data) . Because the UEs 115-a, 115-b operate in the half duplex mode, the UEs 115-a, 115-b cannot at the same time transmit to, and receive from, UE sidelink information (e.g., SCI, sidelink data) . For example, the UE 115-a cannot simultaneously transmit to, and receive from, the UE 115-b sidelink information. As a result, the half duplex mode may impact a reliability or a latency of sidelink information exchange between the UEs 115-a, 115-b.

Various aspects of the described techniques relate to configuring the UEs 115-a, 115-b to support improvements to sidelink information transmission and reception. For example, to improve a reliability or reduce a latency of sidelink information transmission and reception, the UEs 115-a, 115-b may be configured to rateless code SCI. In the example of FIG. 2, the UE 115-a may be configured to rateless code SCI-1 215 and not rateless code SCI-2 220. In some other examples, the UE 115-a may be configured to rateless code both the SCI-1 215 and the SCI-2 220, but separately. For example, the UE 115-a may encode the SCI-1 215 using a rateless code at a first temporal period, and encode the SCI-2 220 using the rateless code at a second temporal period. In some examples, the UE 115-a may use a same or different rateless code for encoding the SCI-1 215 and the SCI-2 220. In other examples, the UE 115-a may be configured to combine (e.g., aggregate) the SCI-1 215 and the SCI-2 220, and rateless code the combined SCI. Because the UE 115-a is combining SCI from the SCI-1 215 and the SCI-2 220, the UE 115-a may remove some information from the SCI-1 215, such as the SCI-2 220 resource information. The UE 115-a may additionally, or alternatively, zero pad the SCI-1 215 based on a length of the combined SCI-1 215 and SCI-2 220 length for received SCI symbols.

The UE 115-a may be preconfigured with sidelink resources to use for the rateless coded SCI. The base station 105-a may transmit a sidelink resource configuration 225 to the UEs 115-a, 115-b. For example, the base station 105-a may transmit the sidelink resource configuration 225 to the UEs 115-a, 115-b in an RRC configuration message over the communication links 205. Alternatively, the base station 105-a may transmit the sidelink resource configuration 225 to the UEs 115-a, 115-b in downlink control information (DCI) message over the communication links 205. The UE 115-a may determine, based on the sidelink resource configuration 225, time and frequency resources. For example, a time domain location (e.g., an index of a slot ) or a frequency domain location (e.g., an index of a subchannel) , or both, for rateless coding may be preconfigured.

The UE 115-a may determine, based on the sidelink resource configuration 225, a periodicity for periodically transmitting rateless coded SCI. For example, the UE 115-a, may determine that the periodicity is five and, thereby, transmit rateless coded SCI every 5 slots on a particular subchannel. In other examples, the UE 115-a may determine a sliding window for rateless coded SCI. For example, in each slot, there may be at least one rateless coded SCI or multiple rateless coded SCI. In some examples, each slot may have time and frequency resources for a combination of rateless coded SCI and non-rateless coded SCI. That is, in each slot, rateless coded SCI and non-rateless coded SCI may coexist.

The UE 115-a may be configured to signal to the UE 115-b resource usage for the rateless coded SCI. For example, the UE 115-a may append an indication to a header of each rateless coded SCI packet, which informs the UE 115-b an xor-ed subchannel. In some examples, the indication itself may occupy a subchannel, and a predefined generator matrix is then applied to an input symbol from subchannel’s SCI. The indication may be a bit value. For example, a bit value ‘1’ indicates a rateless coded SCI packet, while a bit value of ‘0’ indicates a non-rateless coded SCI packet. In some examples, the indication may include an index of a subchannel to indicate the SCI packet. For a multi-slot with a rateless coded SCI, the UEs 115-a, 115-b may support a multi-dimensional mapping of subchannel. In some other examples, for sliding window based rateless coded SCI, the SCI used subchannel or previous slot is indicated. By rateless coding SCI (e.g., the SCI-1 215, the SCI-2 220) , the UEs 115-a, 115-b may thus experience power saving. The wireless communications system 200 may, as a result, also include features for improvements to sidelink operations and, in some examples, may promote high reliability and low latency sidelink communications, among other benefits.

FIG. 3A illustrates an example of a sidelink resource configuration 300-a that supports network coding for control channels in accordance with aspects of the present disclosure. The sidelink resource configuration 300-a may implement or may be implemented by aspects of the

wireless communications systems

100 and 200 as described with reference to FIGs. 1 and 2. The sidelink resource configuration 300-a may be based on a configuration by a base station 105, and implemented by a UE 115, and may promote higher reliability and lower latency sidelink communications (e.g., transmission and reception of SCI) in a wireless communications system. The sidelink resource configuration 300-a may also be based on a configuration by the base station 105, and implemented by the UE 115 to decrease power consumption by the UE 115, if performing sidelink operations, among other benefits.

The sidelink resource configuration 300-a may allocate time resources (for example, symbols, minislots, slots, subframes, or a frame) as well as frequency resources (for example, carriers, subcarriers, subchannels) . A combination of a time resource, such as a slot, and a frequency resource, such as a subchannel, may define an associated resource element 305. A UE 115 may be preconfigured with sidelink resources to use for rateless coded SCI. In some examples, the sidelink resource configuration 300-a may allocate time and frequency resources for non-rateless coded SCI and rateless coded SCI. For example, the sidelink resource configuration 300-a may allocate non-rateless coded SCI resource elements 310 for a number of slots 330 (e.g., 4 slots) and rateless coded SCI resource elements 315 for a slot 325. In other words, the sidelink resource configuration 300-a may allocate a fixed number of slots for non-rateless coded SCI and rateless coded SCI. The sidelink resource configuration 300-a may thus support coexistence of rateless coded SCI and non-rateless coded SCI.

The UE 115 may determine a periodicity 320 to periodically transmit rateless coded SCI to another UE 115. In some examples, the UE 115 may determine the slot 325 or a subchannel 335, or both, to transmit a rateless coded SCI to another UE 115. In some examples, the UE 115 may determine the slot 325 or the subchannel 335, or both, to transmit a rateless coded SCI to another UE 115, based on the periodicity 320. For example, a UE 115 may determine that the periodicity 320 is five slots and, thereby, transmit rateless coded SCI in a fifth slot (e.g., the slot 325) on a particular subchannel (e.g., the subchannel 335) .

FIG. 3B illustrates an example of a sidelink resource configuration 300-b that supports techniques for rateless coding SCI in accordance with aspects of the present disclosure. The sidelink resource configuration 300-b may implement or may be implemented by aspects of the

wireless communications systems

100 and 200 as described with reference to FIGs. 1 and 2. The sidelink resource configuration 300-b may be based on a configuration by a base station 105, and implemented by a UE 115, and may promote higher reliability and lower latency sidelink communications (e.g., transmission and reception of SCI) in a wireless communications system. The sidelink resource configuration 300-b may also be based on a configuration by the base station 105, and implemented by the UE 115 to decrease power consumption by the UE 115, if performing sidelink operations, among other benefits.

The sidelink resource configuration 300-b may allocate time resources (for example, symbols, minislots, slots, subframes, or a frame) as well as frequency resources (for example, carriers, subcarriers, subchannels) . A combination of a time resource, such as a slot, and a frequency resource, such as a subchannel, may define an associated resource element 305. A UE 115 may be preconfigured with sidelink resources to use for rateless coded SCI. In some examples, the sidelink resource configuration 300-b may allocate time and frequency resources for non-rateless coded SCI and rateless coded SCI. For example, the sidelink resource configuration 300-b may allocate non-rateless coded SCI resource elements 310 for a number of subchannels 340 (e.g., 3 subchannels) and rateless coded SCI resource elements 315 for a subchannel 335. In other words, the sidelink resource configuration 300-b may allocate a fixed number of subchannels for non-rateless coded SCI and rateless coded SCI. The sidelink resource configuration 300-b may thus support coexistence of rateless coded SCI and non-rateless coded SCI.

The UE 115 may determine a sliding resource window for rateless coded SCI. For example, in each slot 325, there may be at least one rateless coded SCI resource element 315 or multiple rateless coded SCI resource elements 315 on which the UE 115 may transmit rateless coded SCI to another UE 115. In the example of FIG. 3B, the UE 115 may determine a slot or a subchannel, or both, to transmit a rateless coded SCI to another UE 115. For example, the UE 115 may determine a subchannel 335 and a slot 325 to transmit rateless coded SCI to another UE 115.

FIG. 4 illustrates an example of a process flow 400 that supports network coding for control channels in accordance with aspects of the present disclosure. The process flow 400 may implement aspects of the wireless communications system 100 and the wireless communications system 200 described with reference to FIGs. 1 and 2, respectively. The process flow 400 may be based on a configuration by a base station 105 and implemented by a UE 115 to promote power saving for the UE 115 by supporting network coding SCI (e.g., SCI-1, SCI-2) . The process flow 400 may also be based on a configuration by the base station 105 and implemented by the UE 115 to promote high reliability and low latency sidelink operations, among other benefits.

In the following description of the process flow 400, the operations between UE 115-c and UE 115-d may be transmitted in a different order than the example order shown, or the operations performed by the UE 115-c and the UE 115-d may be performed in different orders or at different times. Some operations may also be omitted from the process flow 400, and other operations may be added to the process flow 400. The UE 115-c and the UE 115-d may be examples of a UE 115 as described with reference to FIG. 1.

At 405, the UE 115-c may determine first SCI (e.g., SCI-1) . At 410, the UE 115-c may code the first SCI based on a rateless code. For example, the UE 115-c may encode SCI-1 using a network code, such as a LT code, a Raptor code, or the like. At 415, the UE 115-c may also determine second SCI (e.g., SCI-2) . At 420, the UE 115-c may code the second SCI based on the rateless code. For example, the UE 115-c may encode SCI-2 using a network code, such as a LT code, a Raptor code, or the like. In some examples, the UE 115-c may aggregate the first SCI and the second SCI, and jointly code the aggregated first SCI and second SCI. The UE 115-c may, in some examples, discard an indication of one or more time and frequency resources of the second SCI based on aggregating the second SCI with the first SCI. At 425, the UE 115-c may transmit sidelink communications to the UE 115-d. For example, the UE 115-c may transmit the fist rateless coded SCI or the second rateless coded SCI, or both, to the UE 115-d. The UE 115-d may be an anchor node in a wireless communications system, as described in FIGs. 1 and 2, respectively. The UE 115-d may receive multiple SCI encoded with rateless coding from multiple UEs 115 including the UE 115-c, and decode the received SCI (e.g., rateless coded SCI) from the multiple UEs 115 to determine the received fist rateless coded SCI or the second rateless coded SCI, or both, from the UE 115-c.

FIG. 5 shows a block diagram 500 of a device 505 that supports network coding for control channels in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of a UE 115 as described herein. The device 505 may include a receiver 510, a communications manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to network coding for control channels, etc. ) . Information may be passed on to other components of the device 505. The receiver 510 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The receiver 510 may utilize a single antenna or a set of antennas.

The communications manager 515 may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The communications manager 515 may code the first SCI based on a rateless code, and transmit the rateless coded first SCI on a PSCCH. The communications manager 515 may be an example of aspects of the communications manager 810 described herein.

The communications manager 515 may enable the device 505 to provide improvements to sidelink operations. In some implementations, the communications manager 515 may enable the device 505 to encode SCI (e.g., SCI-1 or SCI-2, or both) using a rateless code. The communications manager 515 may enable the device 505 to separately encode various SCI using a rateless code. Additionally or alternatively, the communications manager 515 may enable the device 505 to combine SCI (e.g., SCI-1 or SCI-2, or both) and jointly encode the combined SCI using a rateless code. Based on implementing rateless coding operations on SCI, one or more processors of the device 505 (e.g., processor (s) controlling or incorporated with the communications manager 515) may reduce a latency and increase a reliability associated with SCI transmission and reception, and thereby reduce power consumption and promote high reliability sidelink operations, among other benefits.

The communications manager 515, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 515, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 515, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 515, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 515, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be collocated with a receiver 510 in a transceiver component. For example, the transmitter 520 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The transmitter 520 may utilize a single antenna or a set of antennas.

FIG. 6 shows a block diagram 600 of a device 605 that supports network coding for control channels in accordance with aspects of the present disclosure. The device 605 may be an example of aspects of a device 505, or a UE 115 as described herein. The device 605 may include a receiver 610, a communications manager 615, and a transmitter 635. The device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to network coding for control channels, etc. ) . Information may be passed on to other components of the device 605. The receiver 610 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The receiver 610 may utilize a single antenna or a set of antennas.

The communications manager 615 may be an example of aspects of the communications manager 515 as described herein. The communications manager 615 may include a sidelink information component 620, a sidelink coding component 625, and a sidelink message component 630. The communications manager 615 may be an example of aspects of the communications manager 810 described herein. The sidelink information component 620 may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The sidelink coding component 625 may code the first SCI based on a rateless code. The sidelink message component 630 may transmit the rateless coded first SCI on a PSCCH.

The transmitter 635 may transmit signals generated by other components of the device 605. In some examples, the transmitter 635 may be collocated with a receiver 610 in a transceiver component. For example, the transmitter 635 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The transmitter 635 may utilize a single antenna or a set of antennas.

FIG. 7 shows a block diagram 700 of a communications manager 705 that supports network coding for control channels in accordance with aspects of the present disclosure. The communications manager 705 may be an example of aspects of a communications manager 515, a communications manager 615, or a communications manager 810 described herein. The communications manager 705 may include a sidelink information component 710, a sidelink coding component 715, a sidelink message component 720, a sidelink combo component 725, a sidelink discard component 730, a sidelink resource component 735, a sidelink header component 740, and a sidelink padding component 745. Each of these components may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The sidelink information component 710 may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. In some examples, the sidelink information component 710 may determine the second SCI associated with the sidelink communications based on the first coded SCI. The sidelink coding component 715 may code the first SCI based on a rateless code. In some examples, the sidelink coding component 715 may code the second SCI based on the rateless code. In some examples, the sidelink coding component 715 may separately code the first SCI and the second SCI based on the rateless code. The sidelink message component 720 may transmit the rateless coded first SCI on a PSCCH. In some examples, the sidelink message component 720 may transmit the rateless coded second SCI on a PSSCH.

The sidelink combo component 725 may aggregate the first SCI and the second SCI. In some examples, the sidelink combo component 725 may jointly code the first SCI and the second SCI based on aggregating the first SCI and the second SCI. The sidelink discard component 730 may discard the indication of one or more time and frequency resources of the second SCI associated with the sidelink communications based on aggregating the first SCI and the second SCI. The sidelink resource component 735 may determine a sidelink resource allocation configuration associated with the rateless coded first SCI or the rateless coded second SCI, or both, the sidelink resource allocation configuration including a resource indicator. The sidelink resource component 735 may determine one or more time and frequency resources to transmit the rateless coded first SCI based on the sidelink resource allocation configuration. In some examples, the sidelink resource component 735 may transmit the rateless coded first SCI or the rateless coded second SCI, or both, using the one or more determined time and frequency resources.

The sidelink resource component 735 may determine one or more time and frequency resources to transmit the rateless coded first SCI or the rateless coded second SCI, or both, based on a sliding window. In some examples, the sidelink resource component 735 may transmit the rateless coded first SCI or the rateless coded second SCI, or both, using the one or more determined time and frequency resources during a slot. In some cases, the one or more time and frequency resources are periodic over a set of slots. In some cases, the resource indicator includes an index of a subchannel. In some cases, the one or more time and frequency resources are aperiodic over a set of slots. In some cases, the rateless coded first SCI or the rateless coded second SCI, or both, coexist with non-rateless coded SCI in the slot.

The sidelink header component 740 may append, to a header of a rateless coded SCI packet, an indication of a presence or an absence of a rateless coded SCI packet, where the indication occupies a subchannel. In some cases, the indication further includes an index of the subchannel associated with the rateless coded SCI packet. The sidelink padding component 745 may pad the first SCI based on a size of the first SCI and the second SCI.

FIG. 8 shows a diagram of a system 800 including a device 805 that supports network coding for control channels in accordance with aspects of the present disclosure. The device 805 may be an example of or include the components of device 505, device 605, or a UE 115 as described herein. The device 805 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 810, an I/O controller 815, a transceiver 820, an antenna 825, memory 830, and a processor 840. These components may be in electronic communication via one or more buses (e.g., bus 845) .

The communications manager 810 may determine first SCI associated with sidelink communications. The first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The communications manager 810 may code the first SCI based on a rateless code, and transmit the rateless coded first The communications manager 810 may on a PSCCH.

The communications manager 810 may enable the device 805 to provide improvements to sidelink operations. In some implementations, the communications manager 810 may enable the device 805 to encode SCI (e.g., SCI-1 or SCI-2, or both) using a rateless code. The communications manager 810 may enable the device 805 to separately encode various SCI using a rateless code. Additionally or alternatively, the communications manager 810 may enable the device 805 to combine SCI (e.g., SCI-1 or SCI-2, or both) and jointly encode the combined SCI using a rateless code. Based on implementing rateless coding operations on SCI, one or more processors of the device 805 (e.g., processor (s) controlling or incorporated with the communications manager 810) may reduce a latency and increase a reliability associated with SCI transmission and reception, and thereby reduce power consumption and promote high reliability sidelink operations, among other benefits.

The I/O controller 815 may manage input and output signals for the device 805. The I/O controller 815 may also manage peripherals not integrated into the device 805. In some cases, the I/O controller 815 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 815 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 815 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 815 may be implemented as part of a processor. In some cases, a user may interact with the device 805 via the I/O controller 815 or via hardware components controlled by the I/O controller 815.

The transceiver 820 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 820 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 820 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. In some cases, the device 805 may include a single antenna 825. However, in some cases, the device 805 may have more than one antenna 825, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 830 may include RAM and ROM. The memory 830 may store computer-readable, computer-executable code 835 including instructions that, when executed, cause the processor 840 to perform various functions described herein. In some cases, the memory 830 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices. The code 835 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 835 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 835 may not be directly executable by the processor 840 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

The processor 840 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 840 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks supporting network coding for control channels) .

FIG. 9 shows a flowchart illustrating a method 900 that supports network coding for control channels in accordance with aspects of the present disclosure. The operations of method 900 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 900 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 905, the UE may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The operations of 905 may be performed according to the methods described herein. In some examples, aspects of the operations of 905 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 910, the UE may code the first SCI based on a rateless code. The operations of 910 may be performed according to the methods described herein. In some examples, aspects of the operations of 910 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 915, the UE may transmit the rateless coded first SCI on a PSCCH. The operations of 915 may be performed according to the methods described herein. In some examples, aspects of the operations of 915 may be performed by a sidelink message component as described with reference to FIGs. 5 through 8.

FIG. 10 shows a flowchart illustrating a method 1000 that supports network coding for control channels in accordance with aspects of the present disclosure. The operations of method 1000 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1000 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1005, the UE may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 1010, the UE may code the first SCI based on a rateless code. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 1015, the UE may transmit the rateless coded first SCI on a PSCCH. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be performed by a sidelink message component as described with reference to FIGs. 5 through 8.

At 1020, the UE may determine the second SCI associated with the sidelink communications based on the first coded SCI. The operations of 1020 may be performed according to the methods described herein. In some examples, aspects of the operations of 1020 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 1025, the UE may code the second SCI based on the rateless code. The operations of 1025 may be performed according to the methods described herein. In some examples, aspects of the operations of 1025 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 1030, the UE may transmit the rateless coded second SCI on a PSSCH. The operations of 1030 may be performed according to the methods described herein. In some examples, aspects of the operations of 1030 may be performed by a sidelink message component as described with reference to FIGs. 5 through 8.

FIG. 11 shows a flowchart illustrating a method 1100 that supports network coding for control channels in accordance with aspects of the present disclosure. The operations of method 1100 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1100 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1105, the UE may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 1110, the UE may code the first SCI based on a rateless code. The operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 1115, the UE may determine the second SCI associated with the sidelink communications based on the first coded SCI. The operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 1120, the UE may code the second SCI based on the rateless code. The operations of 1120 may be performed according to the methods described herein. In some examples, aspects of the operations of 1120 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 1125, the UE may determine a sidelink resource allocation configuration associated with the rateless coded first SCI or the rateless coded second SCI, or both, the sidelink resource allocation configuration including a resource indicator. The operations of 1125 may be performed according to the methods described herein. In some examples, aspects of the operations of 1125 may be performed by a sidelink resource component as described with reference to FIGs. 5 through 8.

At 1130, the UE may determine one or more time and frequency resources to transmit the rateless coded first SCI based on the sidelink resource allocation configuration. The operations of 1130 may be performed according to the methods described herein. In some examples, aspects of the operations of 1130 may be performed by a sidelink resource component as described with reference to FIGs. 5 through 8.

At 1135, the UE may transmit the rateless coded first SCI or the rateless coded second SCI, or both, using the one or more determined time and frequency resources. The operations of 1135 may be performed according to the methods described herein. In some examples, aspects of the operations of 1135 may be performed by a sidelink resource component as described with reference to FIGs. 5 through 8.

FIG. 12 shows a flowchart illustrating a method 1200 that supports network coding for control channels in accordance with aspects of the present disclosure. The operations of method 1200 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1200 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1205, the UE may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The operations of 1205 may be performed according to the methods described herein. In some examples, aspects of the operations of 1205 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 1210, the UE may code the first SCI based on a rateless code. The operations of 1210 may be performed according to the methods described herein. In some examples, aspects of the operations of 1210 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 1215, the UE may determine the second SCI associated with the sidelink communications based on the first coded SCI. The operations of 1215 may be performed according to the methods described herein. In some examples, aspects of the operations of 1215 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 1220, the UE may code the second SCI based on the rateless code. The operations of 1220 may be performed according to the methods described herein. In some examples, aspects of the operations of 1220 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 1225, the UE may determine one or more time and frequency resources to transmit the rateless coded first SCI or the rateless coded second SCI, or both, based on a sliding window. The operations of 1225 may be performed according to the methods described herein. In some examples, aspects of the operations of 1225 may be performed by a sidelink resource component as described with reference to FIGs. 5 through 8.

At 1230, the UE may transmit the rateless coded first SCI or the rateless coded second SCI, or both, using the one or more determined time and frequency resources during a slot. The operations of 1230 may be performed according to the methods described herein. In some examples, aspects of the operations of 1230 may be performed by a sidelink resource component as described with reference to FIGs. 5 through 8.

FIG. 13 shows a flowchart illustrating a method 1300 that supports network coding for control channels in accordance with aspects of the present disclosure. The operations of method 1300 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1300 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1305, the UE may determine first SCI associated with sidelink communications, the first SCI including an indication of one or more time and frequency resources of second SCI associated with the sidelink communications. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed by a sidelink information component as described with reference to FIGs. 5 through 8.

At 1310, the UE may code the first SCI based on a rateless code. The operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed by a sidelink coding component as described with reference to FIGs. 5 through 8.

At 1315, the UE may append, to a header of a rateless coded SCI packet, an indication of a presence or an absence of a rateless coded SCI packet associated with the first SCI, where the indication occupies a subchannel. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed by a sidelink header component as described with reference to FIGs. 5 through 8.

At 1320, the UE may transmit the rateless coded SCI packet associated with the first SCI on a PSCCH. The operations of 1320 may be performed according to the methods described herein. In some examples, aspects of the operations of 1320 may be performed by a sidelink message component as described with reference to FIGs. 5 through 8.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

The following examples are given by way of illustration. Aspects of the following examples may be combined with aspects or embodiments shown or discussed in relation to the figures or elsewhere herein.

Example 1 is a method for sidelink communications at a UE that includes determining first SCI associated with the sidelink communications, the first SCI includes an indication of one or more time and frequency resources of second control information associated with the sidelink communications; coding the first SCI based at least in part on a rateless code; and transmitting the rateless coded first SCI on a PSCCH.

In Example 2, the method of Example 1, further includes determining the second SCI associated with the sidelink communications based at least in part on the first coded SCI; coding the second SCI based at least in part on the rateless code; and transmitting the rateless coded second SCI on a physical sidelink shared channel.

In Example 3, the method of Example 2, further includes separately coding the first SCI and the second SCI based at least in part on the rateless code.

In Example 4, the method of Example 2, further includes aggregating the first SCI and the second SCI, wherein coding the first SCI and the second SCI further includes jointly coding the first SCI and the second SCI based at least in part on aggregating the first SCI and the second SCI.

In Example 5, the method of any of Examples 1 to 4, further includes discarding the indication of the one or more time and frequency resources of the second control information associated with the sidelink communications based at least in part on aggregating the first SCI and the second SCI.

In Example 6, the method of Example 2, further includes determining a sidelink resource allocation configuration associated with the rateless coded first SCI or the rateless coded second SCI, or both, the sidelink resource allocation configuration comprising a resource indicator; determining one or more time and frequency resources to transmit the rateless coded first SCI based at least in part on the sidelink resource allocation configuration, wherein transmitting the rateless coded first SCI or the rateless coded second SCI, or both, further includes transmitting the rateless coded first SCI or the rateless coded second SCI, or both, using the one or more determined time and frequency resources.

In Example 7, the method of Example 6, wherein the one or more time and frequency resources are periodic over a plurality of slots.

In Example 8, the method of Example 6, wherein the resource indicator comprises an index of a subchannel.

In Example 9, the method of Example 6, further includes appending, to a header of a rateless coded SCI packet, an indication of a presence or an absence of a rateless coded SCI packet, wherein the indication occupies a subchannel.

In Example 10, the method of Example 2, further includes determining one or more time and frequency resources to transmit the rateless coded first SCI or the rateless coded second SCI, or both, based at least in part on a sliding window, wherein transmitting the rateless coded first SCI or the rateless coded second SCI, or both, further includes transmitting the rateless coded first SCI or the rateless coded second SCI, or both, using the one or more determined time and frequency resources during a slot.

In Example 11, the method of Example 10, wherein the one or more time and frequency resources are aperiodic over a plurality of slots.

In Example 12, the method of Example 10, wherein the rateless coded first SCI or the rateless coded second SCI, or both, coexist with non-rateless coded SCI in the slot.

In Example 13, the method of any of Examples 1 to 12, further includes appending, to a header of a rateless coded SCI packet, an indication of a presence or an absence of a rateless coded SCI packet, wherein the indication occupies a subchannel.

In Example 14, the method of Example 13, wherein the indication further comprises an index of the subchannel associated with the rateless coded SCI packet.

In Example 15, the method of any of Example 1 to 14, further includes padding the first SCI based at least in part on a size of the first SCI and the second SCI.

Example 16 is a system including one or more processors and memory in electronic communication with the one or more processors storing instructions executable by the one or more processors to cause the system or apparatus to implement a method as in any of Examples 1 to 15.

Example 17 is a system or apparatus including means for implementing a method or realizing an apparatus as in any of Examples 1 to 15.

Example 18 is a non-transitory computer-readable medium storing instructions executable by one or more processors to cause the one or more processors to implement a method as in any of Examples 1 to 15.

Aspects of these examples may be combined with aspects or embodiments disclosed in other implementations.

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, 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 processor, controller, microcontroller, or state machine. A 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) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for sidelink communications at a user equipment (UE) , comprising:

determining first sidelink control information associated with the sidelink communications, the first sidelink control information comprising an indication of one or more time and frequency resources of second sidelink control information associated with the sidelink communications;

coding the first sidelink control information based at least in part on a rateless code; and

transmitting the rateless coded first sidelink control information on a physical sidelink control channel.
The method of claim 1, further comprising:

determining the second sidelink control information associated with the sidelink communications based at least in part on the first coded sidelink control information;

coding the second sidelink control information based at least in part on the rateless code; and

transmitting the rateless coded second sidelink control information on a physical sidelink shared channel.
The method of claim 2, further comprising:

separately coding the first sidelink control information and the second sidelink control information based at least in part on the rateless code.
The method of claim 2, further comprising:

aggregating the first sidelink control information and the second sidelink control information, wherein coding the first sidelink control information and the second sidelink control information comprises:

jointly coding the first sidelink control information and the second sidelink control information based at least in part on aggregating the first sidelink control information and the second sidelink control information.
The method of claim 4, further comprising:

discarding the indication of the one or more time and frequency resources of the second sidelink control information associated with the sidelink communications based at least in part on aggregating the first sidelink control information and the second sidelink control information.
The method of claim 2, further comprising:

determining a sidelink resource allocation configuration associated with the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, the sidelink resource allocation configuration comprising a resource indicator; and

determining one or more time and frequency resources to transmit the rateless coded first sidelink control information based at least in part on the sidelink resource allocation configuration, wherein transmitting the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, comprises:

transmitting the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, using the one or more determined time and frequency resources.
The method of claim 6, wherein the one or more time and frequency resources are periodic over a plurality of slots.
The method of claim 6, wherein the resource indicator comprises an index of a subchannel.
The method of claim 6, further comprising:

appending, to a header of a rateless coded sidelink control information packet, an indication of a presence or an absence of a rateless coded sidelink control information packet, wherein the indication occupies a subchannel.
The method of claim 2, further comprising:

determining one or more time and frequency resources to transmit the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, based at least in part on a sliding window, wherein transmitting the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, comprises:

transmitting the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, using the one or more determined time and frequency resources during a slot.
The method of claim 10, wherein the one or more time and frequency resources are aperiodic over a plurality of slots.
The method of claim 10, wherein the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, coexist with non-rateless coded sidelink control information in the slot.
The method of claim 10, further comprising:

appending, to a header of a rateless coded sidelink control information packet, an indication of a presence or an absence of a rateless coded sidelink control information packet, wherein the indication occupies a subchannel.
The method of claim 13, wherein the indication further comprises an index of the subchannel associated with the rateless coded sidelink control information packet.
The method of claim 1, further comprising:

padding the first sidelink control information based at least in part on a size of the first sidelink control information and the second sidelink control information.
An apparatus for sidelink communications, comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

determine first sidelink control information associated with the sidelink communications, the first sidelink control information comprising an indication of one or more time and frequency resources of second sidelink control information associated with the sidelink communications;

code the first sidelink control information based at least in part on a rateless code; and

transmit the rateless coded first sidelink control information on a physical sidelink control channel.
The apparatus of claim 16, wherein the instructions are further executable by the processor to cause the apparatus to:

determine the second sidelink control information associated with the sidelink communications based at least in part on the first coded sidelink control information;

code the second sidelink control information based at least in part on the rateless code; and

transmit the rateless coded second sidelink control information on a physical sidelink shared channel.
The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to:

separately code the first sidelink control information and the second sidelink control information based at least in part on the rateless code.
The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to:

aggregate the first sidelink control information and the second sidelink control information, wherein the instructions to code the first sidelink control information and the second sidelink control information are executable by the processor to cause the apparatus to:

jointly code the first sidelink control information and the second sidelink control information based at least in part on aggregating the first sidelink control information and the second sidelink control information.
The apparatus of claim 19, wherein the instructions are further executable by the processor to cause the apparatus to:

discard the indication of the one or more time and frequency resources of the second sidelink control information associated with the sidelink communications based at least in part on aggregating the first sidelink control information and the second sidelink control information.
The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a sidelink resource allocation configuration associated with the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, the sidelink resource allocation configuration comprising a resource indicator; and

determine one or more time and frequency resources to transmit the rateless coded first sidelink control information based at least in part on the sidelink resource allocation configuration, wherein the instructions to transmit the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, are executable by the processor to cause the apparatus to:

transmit the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, using the one or more determined time and frequency resources.
The apparatus of claim 21, wherein the one or more time and frequency resources are periodic over a plurality of slots.
The apparatus of claim 21, wherein the resource indicator comprises an index of a subchannel.
The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

append, to a header of a rateless coded sidelink control information packet, an indication of a presence or an absence of a rateless coded sidelink control information packet, wherein the indication occupies a subchannel.
The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to:

determine one or more time and frequency resources to transmit the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, based at least in part on a sliding window, wherein the instructions to transmit the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, are executable by the processor to cause the apparatus to:

transmit the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, using the one or more determined time and frequency resources during a slot.
The apparatus of claim 25, wherein the one or more time and frequency resources are aperiodic over a plurality of slots.
The apparatus of claim 25, wherein the rateless coded first sidelink control information or the rateless coded second sidelink control information, or both, coexist with non-rateless coded sidelink control information in the slot.
The apparatus of claim 25, wherein the instructions are further executable by the processor to cause the apparatus to:

append, to a header of a rateless coded sidelink control information packet, an indication of a presence or an absence of a rateless coded sidelink control information packet, wherein the indication occupies a subchannel.
The apparatus of claim 28, wherein the indication further comprises an index of the subchannel associated with the rateless coded sidelink control information packet.
The apparatus of claim 16, wherein the instructions are further executable by the processor to cause the apparatus to:

pad the first sidelink control information based at least in part on a size of the first sidelink control information and the second sidelink control information.
An apparatus for sidelink communications, comprising:

means for determining first sidelink control information associated with the sidelink communications, the first sidelink control information comprising an indication of one or more time and frequency resources of second sidelink control information associated with the sidelink communications;

means for coding the first sidelink control information based at least in part on a rateless code; and

means for transmitting the rateless coded first sidelink control information on a physical sidelink control channel.
A non-transitory computer-readable medium storing code for sidelink communications at a user equipment (UE) , the code comprising instructions executable by a processor to:

determine first sidelink control information associated with the sidelink communications, the first sidelink control information comprising an indication of one or more time and frequency resources of second sidelink control information associated with the sidelink communications;

code the first sidelink control information based at least in part on a rateless code; and

transmit the rateless coded first sidelink control information on a physical sidelink control channel.