DISCOVERY POOL FOR SIDELINK

Certain aspects provide a method for wireless communication by a first user-equipment (UE). The method generally includes determining a first configuration for communication with a second UE of one or more discovery messages on a sidelink channel and a second configuration for data communication with the second UE on the sidelink channel, wherein the first configuration is different than the second configuration, and communicating with the second UE in accordance with at least one of the first configuration or the second configuration.

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for sidelink communication.

Description of Related Art

SUMMARY

Certain aspects provide a method for wireless communication by a first user-equipment (UE). The method generally includes determining a first configuration for communication with a second UE of one or more discovery messages on a sidelink channel and a second configuration for data communication with the second UE on the sidelink channel, wherein the first configuration is different than the second configuration, and communicating with the second UE in accordance with at least one of the first configuration or the second configuration.

Certain aspects provide a method for wireless communication. The method generally includes determining a first configuration for communication of one or more discovery messages on a sidelink channel between a first UE and a second UE and a second configuration for data communication on the sidelink channel, wherein the first configuration is different than the second configuration, and transmitting an indication of the first configuration and the second configuration.

Certain aspects provide an apparatus for wireless communication by a first user-equipment (UE). The apparatus generally includes a processing system configured to determine a first configuration for communication with a second UE of one or more discovery messages on a sidelink channel and a second configuration for data communication with the second UE on the sidelink channel, wherein the first configuration is different than the second configuration, and a transceiver configured to communicate with the second UE in accordance with at least one of the first configuration or the second configuration.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes a processing system configured to determine a first configuration for communication of one or more discovery messages on a sidelink channel between a first UE and a second UE and a second configuration for data communication on the sidelink channel, wherein the first configuration is different than the second configuration, and a transmitter configured to transmit an indication of the first configuration and the second configuration.

Certain aspects provide an apparatus for wireless communication by a first user-equipment (UE). The apparatus generally includes means for determining a first configuration for communication with a second UE of one or more discovery messages on a sidelink channel and a second configuration for data communication with the second UE on the sidelink channel, wherein the first configuration is different than the second configuration, and means for communicating with the second UE in accordance with at least one of the first configuration or the second configuration.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes means for determining a first configuration for communication of one or more discovery messages on a sidelink channel between a first UE and a second UE and a second configuration for data communication on the sidelink channel, wherein the first configuration is different than the second configuration, and means for transmitting an indication of the first configuration and the second configuration.

Certain aspects provide a computer-readable medium having instructions stored thereon to cause a first user-equipment (UE) to determine a first configuration for communication with a second UE of one or more discovery messages on a sidelink channel and a second configuration for data communication with the second UE on the sidelink channel, wherein the first configuration is different than the second configuration, and communicate with the second UE in accordance with at least one of the first configuration or the second configuration.

Certain aspects provide a computer-readable medium having instructions stored thereon to cause an apparatus to determine a first configuration for communication of one or more discovery messages on a sidelink channel between a first UE and a second UE and a second configuration for data communication on the sidelink channel, wherein the first configuration is different than the second configuration, and transmit an indication of the first configuration and the second configuration.

Aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing the methods described herein.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for configuring sidelink discovery and data communication. For example, in some aspects, various configurations for performing discovery and data communication may be configured separately. These configurations may include resources for discovery and data communication, power control configurations, power saving configurations, periodicity, priority, or any combination thereof. Some aspects provide techniques for signaling configurations to UEs. For instance, configurations may be signaled using radio resource control (RRC) signaling, or system information block (SIB). One or more bits may be included to distinguish resources being configured for discovery from resources being configured for data communication, as described in more detail herein.

FIG.1illustrates an example wireless communication network100in which aspects of the present disclosure may be performed. For example, the wireless communication network100may be an NR system (e.g., a 5G NR network).

According to certain aspects, the UEs120may be configured to perform discovery operations. As shown inFIG.1, the UE120aincludes a discovery manager122. The discovery manager122may be configured to determine a first configuration for communication with a second UE (e.g., UE120t) of one or more discovery messages on a sidelink channel and a second configuration for data communication with the second UE on the sidelink channel, the first configuration being different than the second configuration, and communicating with the second UE in accordance with at least one of the first configuration or the second configuration, as described in more detail herein. The BS110aincludes a discovery manager112. The discovery manager112may be configured to determine a first configuration for communication of one or more discovery messages on a sidelink channel between a first UE (e.g., UE120a) and a second UE (e.g., UE120t) and a second configuration for data communication on the sidelink channel, wherein the first configuration is different than the second configuration, and transmit an indication of the first configuration and the second configuration.

Wireless communication network100may also include relay stations (e.g., relay station110r), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS110aor a UE120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE120or a BS110), or that relays transmissions between UEs120, to facilitate communication between devices.

A network controller130may couple to a set of BSs110and provide coordination and control for these BSs110. The network controller130may communicate with the BSs110via a backhaul. The BSs110may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

FIG.2illustrates example components of BS110aand UE120a(e.g., in the wireless communication network100ofFIG.1), which may be used to implement aspects of the present disclosure.

At the BS110a, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the physical downlink shared channel (PDSCH), etc. The processor220may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor220may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor230may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)232a-232t. Each modulator232may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators232a-232tmay be transmitted via the antennas234a-234t, respectively.

The memories242and282may store data and program codes for BS110aand UE120a, respectively. A scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

The controller/processor280and/or other processors and modules at the UE120amay perform or direct the execution of processes for the techniques described herein. As shown inFIG.2, the controller/processor280of the UE120ahas the discovery manager122, and the controller/processor280of the BS110has the discovery manager112. Although shown at the Controller/Processor, other components of the UE120amay be used performing the operations described herein.

FIGS.3A and3Bshow diagrammatic representations of example vehicle to everything (V2X) systems in accordance with some aspects of the present disclosure. For example, the UEs shown inFIGS.3A and3Bmay communicate via sidelink channels and may perform sidelink CSI reporting as described herein.

The V2X systems, provided inFIGS.3A and3Bprovide two complementary transmission modes. A first transmission mode, shown by way of example inFIG.3A, involves direct communications (for example, also referred to as side link communications) between participants in proximity to one another in a local area. A second transmission mode, shown by way of example inFIG.3B, involves network communications through a network, which may be implemented over a Uu interface (for example, a wireless communication interface between a radio access network (RAN) and a UE). As illustrated, UEs352,354may communicate with each other using a sidelink (SL)398.

Referring toFIG.3A, a V2X system300(for example, including vehicle to vehicle (V2V) communications) is illustrated with two UEs302,304(e.g., vehicles). The first transmission mode allows for direct communication between different participants in a given geographic location. As illustrated, a vehicle can have a wireless communication link306with an individual (V2P) (for example, via a UE) through a PC5 interface. Communications between the UEs302and304may also occur through a PC5 interface308. In a like manner, communication may occur from a UE302to other highway components (for example, highway component310), such as a traffic signal or sign (V2I) through a PC5 interface312. With respect to each communication link illustrated inFIG.3A, two-way communication may take place between elements, therefore each element may be a transmitter and a receiver of information. The V2X system300may be a self-managed system implemented without assistance from a network entity. A self-managed system may enable improved spectral efficiency, reduced cost, and increased reliability as network service interruptions do not occur during handover operations for moving vehicles. The V2X system may be configured to operate in a licensed or unlicensed spectrum, thus any vehicle with an equipped system may access a common frequency and share information. Such harmonized/common spectrum operations allow for safe and reliable operation.

FIG.3Bshows a V2X system350for communication between a UE352(e.g., vehicle) and a UE354(e.g., vehicle) through a network entity356. These network communications may occur through discrete nodes, such as a base station (for example, an eNB or gNB), that sends and receives information to and from (for example, relays information between) UEs352,354. The network communications through vehicle to network (V2N) links (e.g., Uu links358and310) may be used, for example, for long range communications between vehicles, such as for communicating the presence of a car accident a distance ahead along a road or highway. Other types of communications may be sent by the node to vehicles, such as traffic flow conditions, road hazard warnings, environmental/weather reports, and service station availability, among other examples. Such data can be obtained from cloud-based sharing services.

In some circumstances, two or more subordinate entities (for example, UEs) may communicate with each other using sidelink signals. As described above, V2V and V2X communications are examples of communications that may be transmitted via a sidelink. Other applications of sidelink communications may include public safety or service announcement communications, communications for proximity services, communications for UE-to-network relaying, device-to-device (D2D) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh communications, among other suitable applications. Generally, a sidelink may refer to a direct link between one subordinate entity (for example, UE1) and another subordinate entity (for example, UE2). As such, a sidelink may be used to transmit and receive a communication (also referred to herein as a “sidelink signal”) without relaying the communication through a scheduling entity (for example, a BS), even though the scheduling entity may be utilized for scheduling or control purposes. In some examples, a sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

Various sidelink channels may be used for sidelink communications, including a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The PSDCH may carry discovery expressions that enable proximal devices to discover each other. The PSCCH may carry control signaling such as sidelink resource configurations and other parameters used for data transmissions, and the PSSCH may carry the data transmissions. The PSFCH may carry feedback such as channel state information (CSI) related to a sidelink channel quality.

Example Techniques for Configuring a Discovery Pool for Sidelink

Certain aspects of the present disclosure to techniques for configuring a pool of resources for discovery (also referred to as a discovery pool) to be used for sidelink communication. Discovery operations as described herein are used by remote UEs to connect to another UE (e.g., a relay UE) for data communication. As used herein, data communication generally refers to data communication and feedback between UEs based on an established link. In certain aspects of the present disclosure, resources for discovery may be configured separately from resources to be used for communication in sidelink, as described in more detail herein.

For long-term evolution (LTE), discovery pool and communication pool may be separately configured in a radio resource control (RRC) reconfiguration message, system information block (SIB), or may be preconfigured (e.g., in a standard). For example, common communication pools may be provided in LTE SIB18, and common discovery pools may be provided in LTE SIB19, for UE's in idle mode of operation. A common pool of resources generally refers to resources available to multiple UEs for a particular purpose (e.g., data communication or discovery). Common communication and discovery pools may be separately provided in pre-configuration for out-of-coverage (OOC) UEs. Dedicated communication and discovery pools may be separately provided in RRC reconfiguration message for UEs in a connected mode of operation. A dedicated pool of resources generally refers to a resources dedicated to a particular UE for communication or discovery.

In some cases, transmit (TX) and receive (RX) pools may be configured. For example, a common TX pool may be configured in SIB or preconfigured. The common TX pool may be overwritten by dedicated configuration via RRC reconfiguration message. RX pool may always be common across UEs for LTE, and may be only provided (e.g., configured) via RRC message upon handover (HO). An RX pool may be agnostic to the RRC state of the UE. In some implementations, dedicated assignment of resources may only be configured for a TX pool.

There are various differences between discovery and communication pools. For example, sidelink control information (SCI) may not be used for discovery messages. Both communication and discovery pools may be defined by a periodic subframe pool of resources in time domain and periodic pool of resource blocks (RBs) pool in frequency domain. Communication pool and discovery pool may share the same RB pool definition in LTE. For example, the bandwidth for discovery and communication pools may be 2 RB to 200 RB, and the start position of the pools of resources may be configurable. For a communication pool, separate frequency allocations may be defined for control and data transmissions. The communication pool and discovery pool may use different periodicity configurations. For instance, the periodicity of communication pool may be 40 ms to 320 ms, but the periodicity for discovery pool may be 320 ms to 10.24 seconds. In other words, communication pools may be denser than discovery pools.

FIGS.4A and4Billustrate messages for discovery in sidelink.FIG.4Aillustrates a discovery protocol referred to as “Model A” discovery. As illustrated, UE402may transmit announcement messages412,414,416,418using a pool of resources configured for discovery. The announcement messages may be received by other UEs404,406,408,410that may be monitoring for the announcement messages. The announcement messages may be sent in a PC5 communication channel, as described with respect toFIG.3. Once received, one or more of the announcement messages may be used for the UE402to connect with one or more of UEs404,406,408,410.

FIG.4Billustrates a discovery protocol referred to as “Model B” discovery. As illustrated, UE402may be a discoverer UE and may be transmitting solicitation messages452,454,456,458. The solicitation messages may be received by one or more UEs404,406,408,410. For example, as illustrated, UE404and UE406may transmit response messages460,462back to UE402to facilitate connection on sidelink. For instance, the UE402may perform channel measurements to select one of the UEs404,406having the highest link quality, and perform connection establishment with the selected UE.

FIG.5illustrates a protocol500for relay selection, in accordance with certain aspects of the present disclosure. As illustrated, a UE504may act as a relay UE to relay data between the UE502and the network (e.g., gateway (GW)510). For example, at block512, the UE504may attached to the network, and perform authorization and provision for UE to network relay operations. At block514, the UE504may establish RRC connection with base station506(e.g., eNB). The UE504may then transmit sidelink UE information516to base station506, receive RRC reconfiguration message518, and transmit RRC reconfiguration complete message520.

Once RRC reconfiguration has been completed, discovery operations may be performed. The remote UE502may identify the presence of at least one suitable relay UE to request relay service in its proximity. The relay UE is identified via a discovery message. For example, the relay UE may announce its presence by transmitting sidelink (SL) discovery messages periodically (e.g., in accordance with Model A discovery) or the remote UE may transmit a SL discovery solicitation message, expecting a relay nearby to respond (e.g., in accordance with Model B discovery).

For example, the relay UE504may transmit a relay announcement522to a remote UE502. The relay announcement522may correspond to one of announcement messages412,414,416,418described with respect toFIG.4A. In some cases, the relay announcement522may correspond to one of response messages460,462described with respect toFIG.4B. For example, for Model B discovery, the remote UE502may transmit a relay discovery request524(e.g., corresponding to one of solicitation messages452,454,456,458), and the relay announcement522may be in response to the relay discovery request524. At block526, direct communication may be established based on the relay announcement522. In other words, during relay discovery, the remote UE502obtains the UE ID of the relay UE504to be used for SL transmission and reception of the relayed traffic.

As illustrated, the relay UE504may transmit a remote UE report528to the Mobility Management Entity (MME)508indicating that the relay UE will be acting as a relay for remote UE502. The relay UE504may then receive a remote UE response530, after which user data532may be communicated between the remote UE502and the network with the relay UE504acting as a relay.

FIG.6is a flow diagram illustrating example operations600for wireless communication, in accordance with certain aspects of the present disclosure. The operations600may be performed, for example, by a BS (e.g., such as the BS110ain the wireless communication network100).

Operations600may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor240ofFIG.2). Further, the transmission and reception of signals by the BS in operations600may be enabled, for example, by one or more antennas (e.g., antennas234ofFIG.2). In certain aspects, the transmission and/or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., controller/processor240) obtaining and/or outputting signals.

The operations600may begin, at block605, by the BS determining a first configuration for communication of one or more discovery messages on a sidelink channel between a first UE and a second UE and a second configuration for data communication on the sidelink channel. In certain aspects of the present disclosure, the first configuration may be different than the second configuration. At block610, the BS transmits an indication of the first configuration and the second configuration.

FIG.7is a flow diagram illustrating example operations700for wireless communication, in accordance with certain aspects of the present disclosure. The operations700may be performed, for example, by a first UE (e.g., such as a UE120tin the wireless communication network100).

Operations700may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor280ofFIG.2). Further, the transmission and reception of signals by the first UE in operations700may be enabled, for example, by one or more antennas (e.g., antennas252ofFIG.2). In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller/processor280) obtaining and/or outputting signals.

The operations700may begin, at block705, by the first UE determining a first configuration for communication with a second UE of one or more discovery messages on a sidelink channel and a second configuration for data communication with the second UE on the sidelink channel. In certain aspects, the first configuration may be different than the second configuration. In certain aspects, determining the first and second configuration may involve receiving indication of the first and second configurations from a base station. At block710, the first UE communicates with the second UE in accordance with at least one of the first configuration or the second configuration. In other words, the first UE may transmit or receive discovery messages to establish connection with the second UE. After connection is established, the first UE may use the second configuration for data communication to communicate with the second UE.

In some cases, physical sidelink control channel (PSCCH) and physical sidelink shared channel (PSSCH) may be used for transmission of discovery messages. In certain aspects of the present disclosure, discovery resource pool may be configured separately from the communication channel. In other words, separate discovery and communication resource pools may be configured. In this manner, collision between communication and discovery messages may be reduced.

In certain aspects, separate power saving schemes may be used for discovery and communication resource pools. For instance, the first configuration for communication of the one or more discovery messages may be a first DRX pattern, and the second configuration for data communication may be a second DRX pattern, the first DRX pattern being different than the second DRX pattern. That is, different discontinuous reception (DRX) patterns may be configured for discovery and communication pools.

In some aspects, separate power control schemes may be used. For example, determining the first configuration for discovery may include determining a first power control scheme for the communication of the one or more discovery message, and determining the second configuration for data communication may include determining a second power control scheme for the data communication, the first power control scheme being different than the second power control scheme. In some aspects, determining the first configuration may include determining to transmit the one or more discovery messages using maximum transmit power. In other words, discovery messages may be configured for transmission using maximum transmit power while for communication, which may be unicast, a power-controlled scheme (e.g., open loop power control or closed loop power control) may be used.

In certain aspects, different time and frequency resources may be configured for discovery and communication pools. For example, the first configuration for discovery may include a configuration of first resources for the communication of the one or more discovery messages, and the second configuration for the data communication may include a configuration of second resources for the data communication, the first resources being a different time and frequency than the second resources. In other aspects, the discovery pool and communication pool may share the same time and frequency resources. In this case, it may be up to network implementation to configure a longer periodicity for the discovery pool as compared to periodicity for the communication pool. For example, the first configuration for discovery may include a configuration of a longer periodicity for the communication of the one or more discovery messages as compared to a periodicity for the data communication.

In certain aspects, different discovery priority levels may be configured for different services. For example, a relay UE and a remote UE may obtain a service code from the network. The service code may indicate a quality of service (QoS) associated with a service for which discovery operations are implemented. In other words, discovery messages may have different QoS and latency specifications, and may be configured with different periodicities accordingly. For example, discovery messages configured for a service with low latency specification may be configured with a shorter periodicity, allowing faster discovery between UEs.

In certain aspects, discovery pools may be configured via a system information block, RRC message, or preconfigured at the UE (e.g., included in a standard). To achieve resource pool separation, distinction may be implemented in resource pool configuration. For example, 1-bit indication may be included in a configuration message (e.g., SIB or RRC) indicating whether certain resources being scheduled is for discovery. For example, the first UE, as described with respect to FIG.7, may receive one or more messages indicating the first configuration for the communication of the one or more discovery messages and the second configuration for the data communication. The one or more messages may include a message scheduling resources for the communication of the discovery messages, the message having a bit indicating that the resources being scheduled are to be used for discovery. In certain aspects, the one or more messages may include a message scheduling resources, the message having at least two bits indicating that the resources being scheduled are to be used for discovery only, data communication only, or for either discovery or data communication. In other words, a 2-bit indication may be included in a configuration message indicating whether certain resources being scheduled is for discovery and communication, discovery only, or communication only.

When adding a 1-bit or 2-bit indication in configuration message, discovery pool configuration and communication pool configuration may be included in the same message (e.g., SIB). For example, a resource pool for V2X communication on sidelink may be configured via SIB. The configuration implementation for V2X using SIB may be used, but with additional one or more bits to configure certain resources for discovery.

In certain aspects, a separate resource pool configuration may be used for discovery. For example, discovery pool configuration may be included in a different SIB than a communication pool configuration. That is, the one or more messages including the first configuration for discovery and the second configuration for data communication may include a first message (e.g., first SIB) indicating the first configuration for the communication of the one or more discovery messages and a second message (e.g., second SIB) indicating the second configuration for the data communication.

In certain aspects, the configuration for the discovery pool may be provided in SIB (e.g., for in coverage UE), or preconfigured (e.g., for out-of-coverage (OOC) UE). In some cases, TX pool (e.g., resources for transmission by a UE) may be modified by a dedicated configuration via an RRC reconfiguration message (e.g., RRC reconfiguration message518) for RRC-connected UEs. In certain aspects, an RX pool (e.g., resources for reception by a UE) may be agnostic to the RRC state, and thereby may only be indicated in RRC reconfiguration message upon handover (HO) from one cell to another. RX pool and TX pool generally refer to resources used for reception and transmission, respectively. For example, a network may configure one UE with resources for reception (RX pool), and another UE with the same resources for transmission (TX pool).

In certain aspects, separate power control for discovery and communication may be configured. As described herein, discovery may be used for remote UEs to connect to a relay UE, whereas communication may be based on an established link and feedback. In certain aspects, separate power control configuration for discovery TX pool and communication TX pool may be used. For example, discovery announcement may use maximum power while communication may be power controlled (e.g., using open loop or closed loop power control).

In certain aspects, prioritization rules may be configured for discovery transmission and transmissions for data communication. That is, the discovery pool may be frequency division multiplexed (FDMed) with the communication pool and a UE may end up in a scenario where in one slot, the UE has to perform both discovery and data communications. However, due to certain limitations, the UE may be unable to perform both discovery and data communication in the same slot. As another example, sidelink communication may be configured using a semi static grant, and therefore, the transmission for communication may collide with (e.g., configured with the same resources as) transmissions for discovery.

In such as a scenario, configured prioritization rules may be used to select whether discovery or data communication is to be performed in the slot. For example, communication transmission may be prioritized over discovery based on a direct comparison between associated logical channel (LCH) priorities. In other words, a priority may be configured for a LCH for discovery and a priority may be configured for a LCH for communication. The priorities for discovery and data communication may be extracted from medium access control (MAC)-control element (CE) headers of corresponding LCHs. In certain aspects, QoS (e.g., LCH priority or 5G QoS indicator (5QI)) associated with discovery may be compared with a threshold. For example, if QoS associated with discovery is lower than the threshold, the data communication may be prioritized. In certain aspects, QoS (e.g., LCH priority or 5QI) associated with communication may be compared with a threshold. For example, if the QoS associated with data communication is higher than the threshold, the data communication may be prioritized.

Certain aspects of the present disclosure provide rules for prioritization of physical sidelink feedback channel (PSFCH) and discovery. Data communication as described herein may communication of feedback on PSFCH. The feedback may include, for example, acknowledgment (ACK) or negative ACK (NACK) for data received on a physical sidelink shared channel (PSSCH). The priority associated with PSFCH may be the priority of the associated PSSCH. In other words, if feedback transmission on PSFCH collides with discovery transmission, the priority associated with the discovery may be compared with the priority associated with the PSSCH for which feedback is to be transmitted on PSFCH.

In certain aspects, the transmission on PSFCH may already be sent to lower layers for transmission when the colliding discovery message is ready for transmission. In such a scenario, PSFCH transmission may not be suspended (e.g., even if the priority associated with the discovery message is higher). In certain aspects, a transmission on a sidelink broadcast channel (SL-BCH) may collide with discovery or communication messages. In this case, the transmission on the SL-BCH may be prioritized over transmission for discovery or communication.

FIG.8illustrates a communications device800that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated inFIGS.6and7. The communications device800includes a processing system802coupled to a transceiver808. The transceiver808is configured to transmit and receive signals for the communications device800via an antenna810, such as the various signals as described herein. The processing system802may be configured to perform processing functions for the communications device800, including processing signals received and/or to be transmitted by the communications device800.

The processing system802includes a processor804coupled to a computer-readable medium/memory812via a bus806. In certain aspects, the computer-readable medium/memory812is configured to store instructions (e.g., computer-executable code) that when executed by the processor804, cause the processor804to perform the operations illustrated inFIGS.6and7. In certain aspects, computer-readable medium/memory812stores code814for prioritization (e.g., selection a message to transmit); code816for data receiving/transmitting (e.g., data communicating), code818for determining a configuration, and code820for discovery (e.g., transmitting/receiving discovery messages). In certain aspects, the processor804has circuitry configured to implement the code stored in the computer-readable medium/memory812. The processor804includes circuitry822for prioritization (e.g., selection a message to transmit); circuitry824for data receiving/transmitting (e.g., data communicating); circuitry826for determining a configuration; circuitry828for discovery (e.g., transmitting/receiving discovery messages).

The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G, 4G, and/or 5G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems.

NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, . . . slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. In some examples, MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. In some examples, multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.