Sidelink GroupCast Configuration to Support Feedback Control

Abstract

Methods, systems, and devices for wireless communication are described in which a user equipment (UE) may communicate with one or more other UEs using sidelink communication. A plurality of UEs may form a sidelink communication group and provide sidelink groupcast communication in which the identity of the UE is determined at least in part based on the membership identity of the UE within the group. Each UE in the group may determine feedback resources for acknowledgement feedback within the group based on the UE identity and the size of the group.

Description

[Technical field]

[0001] cross reference This patent application claims priority to U.S. patent application Ser. No. 17 / 031,768, by CHENG et al., entitled “SIDELINK GROUPCAST ​​CONFIGURATION TO SUPPORT FEEDBACK CONTROL,” filed Sep. 24, 2020, which claims the benefit of U.S. Provisional Patent Application Ser. No. 62 / 909,718, by CHENG et al., entitled “SIDELINK GROUPCAST ​​CONFIGURATION TO SUPPORT FEEDBACK CONTROL,” filed Oct. 2, 2019, which is assigned to the assignee of this application.

[0002] The following relates generally to wireless communications, and more particularly to sidelink groupcast configurations. [Background technology]

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasts, and the like. These systems may be capable of supporting communication with multiple users by sharing 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), LTE Advanced (LTE-A), or LTE-A Pro systems, and fifth generation (5G) systems, sometimes 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 multiple access communication system may include several base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, sometimes referred to as user equipment (UE). Summary of the Invention [Means for solving the problem]

[0004] A method of wireless communication in a first UE is described. The method may include receiving sidelink groupcast information of a first sidelink group from a second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The method may also include determining an identity for communication with the first sidelink group based on the sidelink groupcast information at the first UE, and communicating with the first sidelink group based on the determined identity.

[0005] An apparatus for wireless communication in a first UE is described. The apparatus may include a processor and a memory coupled to the processor. The processor and memory may be configured to cause the apparatus to receive sidelink groupcast information of a first sidelink group from a second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The processor and memory may also be configured to cause the apparatus to determine an identity for communication with the first sidelink group at the first UE based on the sidelink groupcast information, and to communicate with the first sidelink group based on the determined identity.

[0006] Another apparatus for wireless communication in a first UE is described. The apparatus may include means for receiving sidelink groupcast information of a first sidelink group from a second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The apparatus may also include means for determining an identity for communication with the first sidelink group based on the sidelink groupcast information and communicating with the first sidelink group based on the determined identity.

[0007] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to receive from a second UE sidelink groupcast information of a first sidelink group including a group size of the first sidelink group and a member identity of the first UE within the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The code may also include instructions executable by the processor to determine an identity for communication with the first sidelink group based on the sidelink groupcast information at the first UE, and to communicate with the first sidelink group based on the determined identity.

[0008] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the identity is a source Layer 2 identity and the member identity of the first UE is included as a first subset of bits of the source Layer 2 identity. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the sidelink groupcast information further includes a group identifier for the first sidelink group. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the group identifier is mapped to a second subset of bits of the destination Layer 2 identity. Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining a Layer 1 identity based on the source Layer 2 identity, where the Layer 1 identity is indicated for the first sidelink group in a physical layer control information transmission. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the Layer 1 identity corresponds to a subset of the source Layer 2 identity indicating a group identifier of the first sidelink group and a membership identity of the first UE within the first sidelink group. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a number of bits of the first subset of bits is determined based on a group size of the first sidelink group.

[0009] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for each of the plurality of members of the first sidelink group to determine whether to use separate feedback resources to provide acknowledgement feedback information to other members of the plurality of members of the first sidelink group based on a group size of the first sidelink group. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first UE determines whether separate or common feedback resources are used to provide acknowledgement feedback information based on whether the number of the plurality of members of the first sidelink group exceeds a threshold number of members. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first UE determines whether separate or common feedback resources are used to provide acknowledgement feedback information based on a pre-configuration of the first UE, control signaling received from another UE or a base station, or any combination thereof. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first UE determines whether a separate feedback resource or a common feedback resource is used to provide acknowledgement feedback information based on radio resource control (RRC) signaling received at the first UE, a system information block (SIB) received at the first UE, a media access control (MAC) control element received at the first UE, or any combination thereof.

[0010] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining a set of feedback resources for transmitting acknowledgement feedback information to one or more members of the first sidelink group based at least in part on a group size of the first sidelink group and a member identity of the first UE within the first sidelink group. Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for receiving a first groupcast communication from a second UE, determining acknowledgement feedback for the first groupcast communication, and transmitting acknowledgement feedback for the first groupcast communication to the second UE using the set of feedback resources.

[0011] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for sending a groupcast communication to other members of the plurality of members of the first sidelink group, monitoring for acknowledgement feedback from other members of the plurality of members of the first sidelink group, and determining to retransmit the groupcast communication based on the acknowledgement feedback from at least one of the plurality of members of the first sidelink group. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining to retransmit may further include operations, features, means, or instructions for determining that at least one of the plurality of members of the first sidelink group provides a negative acknowledgement, determining that acknowledgement feedback from at least one of the plurality of members of the first sidelink group is not received at the first UE, or any combination thereof.

[0012] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for configuring an access stratum layer at the first UE for a quality of service (QoS) flow for groupcast communication associated with the Layer 2 identity, where the access stratum layer determines a QoS flow identity and a QoS context and derives a Layer 1 identity for the QoS flow. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the sidelink groupcast information is received at an application layer of the first UE or at a group management midware layer at the first UE.

[0013] A method of wireless communication in a first UE is described. The method may include configuring a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least a first UE and a second UE, determining a member identity of the first UE, determining a feedback resource configuration for the sidelink group based on a group size of the first sidelink group and the determined member identity of the first UE, and transmitting sidelink groupcast information indicative of at least the feedback resource configuration to other members of the plurality of members of the first sidelink group. The method may also include determining an identity at the first UE for communication with the first sidelink group based on the sidelink groupcast information, and communicating with the first sidelink group based on the determined identity and the feedback resource configuration.

[0014] An apparatus for wireless communication in a first UE is described. The apparatus may include a processor and a memory coupled to the processor. The processor and memory may be configured to cause the apparatus to configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least a first UE and a second UE, determine a member identity of the first UE, determine a feedback resource configuration for the sidelink group based on a group size of the first sidelink group and the determined member identity of the first UE, where the feedback resource configuration includes common feedback resources used by the plurality of members or separate feedback resources corresponding to each of the plurality of members, and transmit sidelink groupcast information indicating at least the feedback resource configuration to other members of the plurality of members of the first sidelink group. The processor and memory may also be configured to cause the apparatus to determine an identity at the first UE for communication with the first sidelink group based on the sidelink groupcast information, and to communicate with the first sidelink group based on the determined identity and the feedback resource configuration.

[0015] Another apparatus for wireless communication in a first UE is described. The apparatus may include means for configuring a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least a first UE and a second UE, determining a member identity of the first UE, determining a feedback resource configuration for the sidelink group based on a group size of the first sidelink group and the determined member identity of the first UE, and transmitting sidelink groupcast information indicative of at least the feedback resource configuration to other members of the plurality of members of the first sidelink group. The apparatus may also include means for determining at the first UE an identity for communication with the first sidelink group based on the sidelink groupcast information, and communicating with the first sidelink group based on the determined identity and the feedback resource configuration.

[0016] A non-transitory computer-readable medium storing code for wireless communication in a first UE is described. The code may include instructions executable by a processor to configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least a first UE and a second UE, determine a member identity of the first UE, determine a feedback resource configuration for the sidelink group based on a group size of the first sidelink group and the determined member identity of the first UE, and transmit sidelink groupcast information indicative of at least the feedback resource configuration to other members of the plurality of members of the first sidelink group. The code may also include instructions executable by a processor to determine an identity at the first UE for communication with the first sidelink group based on the sidelink groupcast information, and to communicate with the first sidelink group based on the determined identity and the feedback resource configuration.

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the feedback resource configuration includes a common feedback resource used by the multiple members or a separate feedback resource corresponding to each of the multiple members. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the separate feedback resource is used to provide acknowledgement feedback information when the number of the multiple members of the first sidelink group is less than or equal to a threshold number of members, and the common resource is used to provide acknowledgement feedback information when the number of the multiple members of the first sidelink group exceeds the threshold number of members. Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting a groupcast communication to other members of the multiple members of the first sidelink group, monitoring for acknowledgement feedback from other members of the multiple members of the first sidelink group based on the feedback resource configuration, and determining to retransmit the groupcast communication based on the acknowledgement feedback from at least one of the multiple members of the first sidelink group. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining to retransmit may further include operations, features, means, or instructions for determining that at least one of the multiple members of the first sidelink group provides a negative acknowledgment, determining that acknowledgment feedback from at least one of the multiple members of the first sidelink group is not received at the first UE, or any combination thereof.

[0018] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first UE determines whether separate or common feedback resources are used to provide the acknowledgement feedback information based on a pre-configuration of the first UE, a control signaling received from another UE or a base station, or any combination thereof. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first UE determines whether separate or common feedback resources are used to provide the acknowledgement feedback information based on an RRC signaling received at the first UE, a SIB received at the first UE, a MAC control element received at the first UE, or any combination thereof. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the number of separate feedback resources corresponds to the number of members of the first sidelink group minus one.

[0019] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the sidelink groupcast information further indicates a group identifier of the first sidelink group, a group size of the first sidelink group, and a corresponding member identity within the first sidelink group for each of the plurality of members. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the identity is a source Layer 2 identity, and an identity of the first UE is included as a first subset of bits of the source Layer 2 identity, where the group identifier is mapped to a second subset of bits of the destination Layer 2 identity. Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining a Layer 1 identity based on the source Layer 2 identity, where the Layer 1 identity is indicated for the first sidelink group in a physical layer control information transmission. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the Layer 1 identity corresponds to a subset of the source Layer 2 identity. In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the number of bits of the first subset of bits is determined based on a group size of the first sidelink group. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 illustrates an example of a system for wireless communication supporting sidelink groupcast configuration to support feedback control, according to an aspect of the present disclosure. [Diagram 2] FIG. 1 illustrates an example of a wireless communication system supporting a sidelink groupcast configuration to support feedback control, according to an aspect of the present disclosure. [Diagram 3] FIG. 1 illustrates an example of a UE protocol stack supporting sidelink groupcast configuration to support feedback control in accordance with an aspect of the present disclosure. [Figure 4] FIG. 1 illustrates an example of a process flow for supporting a sidelink groupcast configuration to support feedback control, according to aspects of the disclosure. [Diagram 5] FIG. 13 is a block diagram of a device supporting a sidelink groupcast configuration to support feedback control, according to an aspect of the disclosure. [Figure 6] FIG. 13 is a block diagram of a device supporting a sidelink groupcast configuration to support feedback control, according to an aspect of the disclosure. [Figure 7] FIG. 13 is a block diagram of a communications manager supporting sidelink groupcast configuration to support feedback control according to an aspect of the disclosure. [Figure 8] FIG. 1 is a diagram of a system including devices supporting a sidelink groupcast configuration to support feedback control, according to an aspect of the disclosure. [Figure 9] 13 is a flowchart illustrating a method for supporting a sidelink group-cast configuration to support feedback control, according to an aspect of the present disclosure. [Figure 10] 13 is a flowchart illustrating a method for supporting a sidelink group-cast configuration to support feedback control, according to an aspect of the present disclosure. [Figure 11] 13 is a flowchart illustrating a method for supporting a sidelink group-cast configuration to support feedback control, according to an aspect of the present disclosure. [Figure 12] 13 is a flowchart illustrating a method for supporting a sidelink group-cast configuration to support feedback control, according to an aspect of the present disclosure. [Figure 13] 13 is a flowchart illustrating a method for supporting a sidelink group-cast configuration to support feedback control, according to an aspect of the present disclosure. [Figure 14]13 is a flowchart illustrating a method for supporting a sidelink group-cast configuration to support feedback control, according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A wireless communication system may support both access links and sidelinks for communication between wireless devices. An access link may refer to a communication link between a UE and a base station. For example, an access link may support uplink signaling, downlink signaling, connection procedures, etc. A sidelink may refer to any communication link between similar wireless devices (e.g., a communication link between UEs or a backhaul communication link between base stations). It should be noted that although various examples provided herein are described with respect to a UE sidelink device, such sidelink techniques may be used for any type of wireless device that uses sidelink communication. For example, a sidelink may support device-to-device (D2D) communication, vehicle-to-everything (V2X) or vehicle-to-vehicle (V2V) communication, message relaying, discovery signaling, beacon signaling, or any combination of these or other signals transmitted over the air from one UE to one or more other UEs.

[0022] As demands for sidelink communications increase (e.g., due to increased V2X demands for autonomous and semi-autonomous vehicles, D2D communications between Internet of Things (IoT) devices, etc.), techniques for efficiently and reliably enhancing the throughput and reliability of sidelink channels are desirable. Techniques as described in various aspects of the present disclosure provide for sidelink groupcast communications in which an identity of a UE is determined based at least in part on a membership identity of the UE within a group. Techniques as described in one or more aspects of the present disclosure may also provide for sidelink groupcast communications in which feedback resources for acknowledgement feedback are based on a UE identity and a size of the group.

[0023] In some cases, the UE may determine whether a common feedback resource set should be shared among multiple UEs of the group or whether separate feedback resources are configured for each UE based at least in part on the size of the group. In some cases, when separate feedback resources are configured for each UE in a group of sidelink groupcast UEs, a specific feedback resource for the UE may be determined based on the UE's position within the group (i.e., UE identity compared to identities associated with other UEs in the group) and the size of the group. For example, a first UE (e.g., based on the minimum value of the UE identifiers of each of the member UEs of the group) may determine that a first set of feedback resources should be used to provide acknowledgement feedback to a second UE of the group. In such a case, a third UE (e.g., with a higher UE identifier value than the second UE) may provide acknowledgement feedback using a second set of feedback resources determined based on the third UE identity minus one due to the second UE not needing acknowledgement feedback resources (i.e., due to the second UE being a transmitting UE that receives acknowledgement feedback from other UEs in the group).

[0024] In some cases, a higher layer, such as an application layer in each UE or a midware layer in each UE, may provide a UE member ID (e.g., based on a communication from a group leader of a group of UEs) to a lower layer (e.g., Layer 2) in the UE. In some implementations, the lower layer may include one or more of a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, or a Media Access Control (MAC) layer in each UE. The identity may then be determined based on the UE member ID, the group identity, the group size, or any combination thereof. In some cases, the UE may map its UE member ID to a first subset of bits of the source Layer 2 ID and the group ID to a second subset of bits in the destination Layer 2 ID.

[0025] Thus, the techniques as described herein provide enhanced reliability and efficiency in determining UE identity and feedback resources in sidelink groupcast communication. For example, by enabling the determination of UE identity and feedback resources based on group size or UE identity or both, efficient determination of feedback resources may be performed without additional signaling and associated added overhead. Furthermore, by determining source Layer 2 ID and destination Layer 2 ID based on UE member ID and group ID, respectively, Layer 2 ID may be determined at each UE, which further reduces signaling and overhead associated with sidelink groupcast configuration. Additionally, in some cases, the decision of whether common or separate feedback resources are used by a group of UEs may be determined at each UE based on group size, which may also enable reduced signaling overhead.

[0026] Aspects of the present disclosure are first described in the context of a wireless communication system. Aspects of the present disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flow charts relating to sidelink groupcast configurations to support feedback control.

[0027] 1 illustrates an example of a wireless communication system 100 supporting a sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. The wireless communication system 100 includes a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, a LTE-Advanced (LTE-A) network, a LTE-A Pro network, or a New Radio (NR) network. In some cases, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

[0028] The base stations 105 may be distributed throughout a geographic area and may be devices of different forms or with different capabilities to form the wireless communication system 100. The base stations 105 and the UEs 115 may communicate wirelessly 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 the communication link 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 support communication of signals via one or more radio access technologies.

[0029] The UEs 115 may be distributed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be fixed or mobile, or both, at various times. The UEs 115 may be devices of different forms or with different capabilities. Some example UEs 115 are shown in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, 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.

[0030] The base stations 105 may communicate with the core network 130, with each other, or both. For example, the base stations 105 may interface with the core network 130 through the backhaul links 120 (e.g., via an S1, N2, N3, or other interface). The base stations 105 may communicate with each other over the backhaul links 120 (e.g., via an X2, Xn, or other interface), either directly (e.g., directly between the base stations 105) or indirectly (e.g., via the 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 as a transceiver base station, radio base station, access point, radio transceiver, Node B, eNode B (eNB), next generation Node B or giga Node B (any of which may be referred to as a gNB), Home Node B, Home eNode B, or other suitable terminology by those skilled in the art. In some examples, the UE 115 may communicate with the core network 130 over a communication link 135.

[0031] The UE 115 may include or 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 a "device" may also be referred to as a unit, a station, a terminal, or a client, among other examples. The UE 115 may also include or 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, the 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, a machine type communication (MTC) device, etc., which may be implemented in various items, such as an appliance, a vehicle, a meter, etc.

[0032] The UEs 115 described herein may be able to communicate with various types of devices, such as base stations 105 and network equipment, including other UEs 115 that may act as relays, as shown in FIG. 1, as well as macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc.

[0033] The UE 115 and the base station 105 may wirelessly communicate with each other via one or more communication links 125 on 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 link 125. For example, a carrier used for the communication link 125 may include a portion (e.g., a bandwidth portion (BWP)) of a radio frequency spectrum band operated according to a physical layer channel 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 communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. The 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 duplex (FDD) and time division duplex (TDD) component carriers.

[0034] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition or control signaling to coordinate operation with respect to other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be arranged according to a channel raster for discovery by the UE 115. A carrier may be operated in a standalone mode where initial acquisition and connection may be made over the carrier by the UE 115, 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 different radio access technology).

[0035] The communication link 125 illustrated in the wireless communication system 100 may include uplink transmissions from the UE 115 to the base station 105 or downlink transmissions from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in FDD mode) or may be configured to carry downlink and uplink communications (e.g., in TDD mode).

[0036] A carrier may refer to a particular bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the carrier or the “system bandwidth” of the wireless communication system 100. For example, the carrier bandwidth may be one of several predefined bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)) for a carrier of a particular radio access technology. The devices (e.g., the base station 105, the UE 115, or both) of the wireless communication system 100 may have a hardware configuration that supports communication over a particular carrier bandwidth or may be configurable to support communication over one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or a UE 115 that supports simultaneous communication over carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate over a portion (e.g., a sub-band, BWP) or all of the carrier bandwidth.

[0037] The electromagnetic spectrum is often subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified with frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as the "sub-6 GHz" band in various documents and papers. Similar nomenclature issues may arise with respect to FR2, which is often referred to (interchangeably) as the "mmWave" band in documents and papers, even though it is different from the extremely high frequency (EHF) band (30 GHz-300 GHz) identified as the "mmWave" band by the International Telecommunications Union (ITU).

[0038] With the above aspects in mind, it should be understood that unless otherwise specified, terms such as "sub-6 GHz" as used herein may broadly refer to frequencies that may be below 6 GHz, may be within FR1, or may include mid-band frequencies. Additionally, it should be understood that terms such as "mmWave" as used herein may broadly refer to frequencies that may include mid-band frequencies, may be within FR2, or may be within the EHF band, unless otherwise specified.

[0039] A signal waveform transmitted on a carrier may be composed of multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique, 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., the duration of one modulation symbol) and one subcarrier, where the symbol period and the 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 the UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communication with the UE 115.

[0040] One or more numerologies for a carrier may be supported, where the numerology may include a subcarrier spacing (Δf) and a cyclic prefix. A carrier may be divided into BWPs having the same or different numerologies. In some examples, a UE 115 may be configured with multiple BWPs. In some cases, a single BWP for a carrier may be active at a given time, and communication for the UE 115 may be constrained to the active BWP.

[0041] The time interval for the base station 105 or the UE 115 may be, for example, T s =1 / (Δf max N f ) seconds, may be expressed in multiples of the base time unit, where Δf max may represent the maximum supported subcarrier spacing, and N fmay represent the maximum discrete Fourier transform (DFT) size supported. The communication resource time intervals 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).

[0042] Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some cases, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into several slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on the subcarrier spacing. Each slot may include several symbol periods (e.g., depending on the length of a cyclic prefix prepended to each symbol period). In some wireless communications systems 100, a slot may be further divided into multiple minislots that include one or more symbols. Excluding the cyclic prefix, each symbol period may include one or more (e.g., N f The duration of a symbol period may depend on the subcarrier spacing or the frequency band of operation.

[0043] A subframe, slot, minislot, or 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 cases, the TTI duration (i.e., 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 a burst of shortened TTIs (sTTIs)).

[0044] The physical channels may be multiplexed on the carriers according to various techniques. The physical control channels and the physical data channels may be multiplexed on the downlink carriers using, for example, time division multiplexing (TDM), frequency division multiplexing (FDM), or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (core set)) for the physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth of the carrier or a subset of the system bandwidth. One or more control regions (e.g., core sets) may be configured for a set of UEs 115. For example, the UEs 115 may monitor or search the control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates at one or more aggregation levels arranged in a cascaded manner. The aggregation level for the control channel candidates may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with the coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for sending control information to multiple UEs 115 and a UE-specific search space set for sending control information to a particular UE 115.

[0045] Each base station 105 may provide communication coverage via one or more cells, e.g., macro cells, small cells, hot spots, or other types of cells, or various combinations thereof. The term “cell” may refer to a logical communication entity used for communication with the base station 105 (e.g., over a carrier) and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other identifier) ​​to distinguish neighboring cells. In some examples, a cell may also refer to a geographic coverage area 110 or a portion (e.g., a sector) of a geographic coverage area 110 on which the logical communication entity operates. Such a cell may range from a smaller area (e.g., a structure, a subset of a structure) to a larger area 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, an outside space between or overlapping with the geographic coverage area 110, and the like.

[0046] A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs 115 subscribing to the service of a network provider supporting the macro cell. A small cell may be associated with a lower power base station 105 compared to a macro cell, and the small cell may operate in the same or different frequency bands (e.g., licensed frequency bands, unlicensed frequency bands) as the macro cell. A small cell may provide unrestricted access to UEs 115 subscribing to the service of a network provider, or may provide restricted access to UEs 115 having an association with a small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with a user in a home or office, etc.). A base station 105 may support one or more cells and may also support communication via one or more cells using one or more 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), or others) that may provide access to different types of devices.

[0047] In some examples, the base stations 105 may be mobile and thus provide communication coverage to moving geographic coverage areas 110. In some examples, the different geographic coverage areas 110 associated with different technologies may overlap, but may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include a heterogeneous network, for example, where different types of base stations 105 provide coverage to various geographic coverage areas 110 using the same or different radio access technologies.

[0048] The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing and transmissions from different base stations 105 may not be aligned in time, in some examples. The techniques described herein may be used for either synchronous or asynchronous operation.

[0049] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices and may provide 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 each other or with the base station 105 without human intervention. In some examples, M2M communication or MTC may include communication from devices that incorporate sensors or meters to measure or capture information and relay such information to a central server or application program that utilizes the information or presents the information to a human 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 billing.

[0050] Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communication (e.g., a mode that supports one-way communication via transmission or reception, but not simultaneous transmission and reception). In some examples, the half-duplex communication may be performed at a reduced peak rate. Other power saving techniques for the UE 115 include entering a power-saving deep sleep mode when not engaged in active communication, operating over a limited bandwidth (e.g., in accordance with narrowband communication), or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type associated with a predefined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a guard band of the carrier, or outside of the carrier.

[0051] The wireless communication system 100 may be configured to support ultra-reliable or low latency communications, or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low latency communications (URLLC) or mission-critical communications. The UE 115 may be designed to support ultra-reliable, low latency, or critical functions (e.g., mission-critical functionality). Ultra-reliable communications may include private or group communications 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 functionality may include service prioritization, and the 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.

[0052] In some cases, the UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105 or may not otherwise be able to receive transmissions from the base station 105. In some cases, a group of UEs 115 communicating via D2D communication 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, the base station 105 facilitates scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without the involvement of the base station 105.

[0053] In some systems, the D2D communication link (e.g., sidelink communication link 140) may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115). In some examples, the vehicles may communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination thereof. The vehicles may signal information related to traffic conditions, signal scheduling, weather, safety, emergency, or any other information relevant to the V2X system. In some cases, the vehicles in the V2X system may communicate with a roadside infrastructure, such as roadside units, or with a network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communication, or both. Additionally, in some cases, groupcast communication between a group of UEs 115 may be performed via the sidelink communication link 140, and configuration of identity and feedback resources in the sidelink groupcast communication may be performed according to various aspects described herein.

[0054] 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 a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) that manages access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), a user plane function (UPF)) that routes packets or interconnects to external networks. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the core network 130. User IP packets may be forwarded through a user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to network operator IP services. Operator IP services may include access to the Internet, intranets, IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0055] Some of the network devices, such as the base station 105, may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). Each access network entity may communicate with the UE 115 through some other access network transmission entity, which may be referred to as a radio head, a smart radio head, or a transmit / receive point (TRP). Each access network transmission entity may include one or more antenna panels. In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or integrated into a single network device (e.g., the base station 105).

[0056] The wireless communication system 100 may operate using one or more frequency bands, such as frequency bands in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). The 300 MHz to 3 GHz region is sometimes referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range in length from approximately 1 decimeter to 1 meter. Although UHF waves may be blocked or redirected by buildings and environmental features, the waves may penetrate structures sufficiently for a macrocell to serve UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) compared to transmissions using lower frequencies and longer waves in the shortwave (high frequency) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0057] The wireless communication system 100 may also operate in the super high frequency (SHF) region, using a frequency band from 3 GHz to 30 GHz, also referred to as the centimeter band, or in the extremely high frequency (EHF) region of the spectrum, also referred to as the millimeter band (e.g., from 30 GHz to 300 GHz). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas of the respective devices may be smaller and more closely spaced than the UHF antennas. In some cases, this may facilitate the use of antenna arrays within the devices. However, propagation of EHF transmissions may be subject to greater atmospheric attenuation and shorter distances than SHF or UHF transmissions. The techniques disclosed herein may be employed over transmissions using one or more different frequency regions, and the designated use of the bands over these frequency regions may vary from country to country or regulatory body.

[0058] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ License Assisted Access (LAA), LTE Unlicensed (LTE-U), or NR technology in an unlicensed band, such as the 5 GHz Industrial, Scientific, and Medical (ISM) band. When operating in an unlicensed radio frequency spectrum band, devices such as the base station 105 and the UE 115 may employ carrier sensing for collision detection and collision avoidance. In some cases, operation in an unlicensed band may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA). Operation in an unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, D2D transmissions, and the like.

[0059] The base station 105 or 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 the base station 105 or UE 115 may be arranged in one or more antenna arrays or antenna panels that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be collocated in an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with the base station 105 may be located in diverse geographic locations. The base station 105 may have an antenna array with several rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals transmitted through the antenna ports.

[0060] A base station 105 or a UE 115 may use MIMO communications to exploit multipath signal propagation and improve 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 be transmitted by a transmitting device via different antennas or different combinations of antennas, for example. Similarly, the multiple signals may be received by a 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). The different spatial layers may be associated with different antenna ports used for channel measurements and channel reporting. MIMO techniques include single-user MIMO (SU-MIMO), in which multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), in which multiple spatial layers are transmitted to multiple devices.

[0061] Beamforming, sometimes referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used in a transmitting or receiving device (e.g., base station 105 or UE 115) to shape or steer an antenna beam (e.g., transmit beam, receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals communicated through antenna elements of an antenna array such that some signals propagating in a particular orientation relative to the antenna array are subject to constructive interference and other signals are subject to destructive interference. Adjustment of signals communicated through antenna elements may include a transmitting or receiving device applying an amplitude offset, a phase offset, or both to signals conveyed through an antenna element 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., relative to the antenna array of the transmitting or receiving device, or relative to some other orientation).

[0062] The wireless communication system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communication at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. The Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate on logical channels. The MAC layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection, error correction, or both techniques to support retransmissions at the MAC layer to improve link efficiency. In the control plane, a Radio Resource Control (RRC) protocol layer may establish, configure, and maintain an RRC connection between the UE 115 and the base station 105 or core network 130, which supports radio bearers for user plane data. In the physical layer, transport channels may be mapped to physical channels.

[0063] The UE 115 and the base station 105 may support retransmission of data to increase the likelihood that the data is successfully received. Hybrid Automatic Repeat Request (HARQ) feedback is one technique for increasing the likelihood that data is correctly received on the 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 cases, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a particular slot for data received in a previous symbol in that slot. In other cases, the device may provide HARQ feedback in a subsequent slot or according to some other time interval.

[0064] One or more of the base stations 105 may include a base station communications manager, which may configure one or more sidelink parameters for sidelink communications between the first UE 115 and the second UE 115 via the sidelink communications link 140 and may send a message to one or more of the sidelink UEs 115 indicating the one or more sidelink parameters.

[0065] The UE 115 may include a UE communications manager 102, which may determine sidelink communications parameters and configurations for sidelink communications. In some cases, the UE communications manager 102 may receive sidelink groupcast information of a sidelink group from another sidelink UE 115, which may include a group size and a UE member identity. Based on the sidelink groupcast information, the UE may determine an identity for communication with the sidelink group and may communicate with the sidelink group based at least in part on the determined identity. In some cases, the UE communications manager 102 may determine a feedback resource configuration for the sidelink group based at least in part on a group size of the sidelink group, which may include a configuration in which acknowledgement feedback is provided by multiple UEs 115 using a common feedback resource or in separate feedback resources by each UE 115. In cases in which separate feedback resources are configured, the specific UE 115 resources within the set of different available resources may be determined based on the group size and the UE position within the group. The UE communications manager 102 may be an example of an aspect of a UE communications manager 810 described herein.

[0066] 2 illustrates an example of a wireless communication system 200 supporting a sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. In some examples, the wireless communication system 200 may implement aspects of the wireless communication system 100. In some examples, the wireless communication system 200 may include a first UE 115-a, a second UE 115-b, a third UE 115-c, a fourth UE 115-d, and a base station 105-a, which may be examples of the UE 115 and base station 105 described with reference to FIG. 1. In some examples, the UE 115-a, the UE 115-b, and the UE 115-c may be members of a group 210 of UEs 115, and the UE 115-d may not be part of the group 210. One or more of the UEs 115 may communicate with the base station 105 using a corresponding access link 225.

[0067] In this example, the first UE 115-a, the second UE 115-b, and the third UE 115-c may be members of a sidelink groupcast communication group in which members of the group may communicate with other members of the group to provide data or other information over the sidelink 205. In some cases, an application layer in the first UE 115-a may prompt the creation of a sidelink groupcast communication group, which may be established through communication with application layers of other UEs 115 in the group. It should be noted that the illustrated sidelink groupcast communication group provides for communication among three UEs 115 shown in the wireless communication system 200 for simplicity, and the techniques described below may be applicable to other numbers of UEs 115 in a system that may establish a groupcast communication group. Additionally, sidelink communication techniques may be used for device-to-device communication of wireless devices other than UEs, such as base station communication (e.g., wireless backhaul links between base stations or transmit receive points (TRPs)), communication between access points, etc.

[0068] In some cases, a higher layer application serving to establish a sidelink groupcast communication group may provide group information to a lower layer (e.g., to a UE access stratum (AS), which may include Layer 2 and Layer 1 layers). Such group information may be used, for example, to determine HARQ feedback resources to be used by each UE 115 receiving communication in the group. In some cases, such HARQ feedback resources may be common acknowledgement resources shared among multiple UEs 115 (e.g., all UEs 115 receiving a groupcast transmission may share the same physical sidelink feedback channel (PSFCH) resource). In other cases, such HARQ resources may include separate acknowledgement feedback resources for different UEs 115 in the group (e.g., each UE 115 receiving a groupcast transmission may use a separate PSFCH resource to provide HARQ feedback). In some cases, separate lower layer signaling (e.g., Layer 1 signaling at the physical layer or AS layer at the UE 115) may not be provided for groupcast communications, and thus, for separate PSFCH resources to be implemented, each UE 115 in a group should be able to individually derive a different PSFCH to use. Thus, the AS layer of each group member UE 115 may require an additional identifier from a higher layer to support independent selection of a PSFCH resource from a list that does not overlap with the PSFCH resources of any other group member.

[0069] For HARQ operation, the AS layer may need an identifier that is unique and can indicate its location within the group. For example, in a group of five members, four PSFCH resources would be needed to provide feedback to the transmitting UE 115, and the receiving UE 115 would need to be able to determine which of the four PSFCH resources to use. In cases where an application layer (e.g., a V2X application layer) provides group identification information for the sidelink groupcast communication group, additional information would be needed to identify a unique ID to the UE 115. Thus, for HARQ operation (such as acknowledgement (ACK)-based feedback), the AS layer of each group member UE 115 would also need to be able to determine if all members have responded so that it can determine whether to perform a retransmission. Furthermore, assuming that each of the group members can act as a transmitter, all UEs 115 in the group should be aware of the group size.

[0070] In some cases, such as platooning, where a group of vehicles travel together in a convoy, an application layer protocol (e.g., V2X application layer) may form a sidelink groupcast communication group, and negotiation may occur between the UEs 115 that are members of the group. A group leader, such as a platoon leader in a platooning application, may possibly know the size of the group and assign a UE member identifier to each of the group members. The group leader may then provide sidelink groupcast information for the sidelink group, which may include the group size and the group member identifier of each UE 115 that is a member, and the sidelink groupcast information may then be provided to the AS layer in each UE 115. This information may be used to identify PSFCH resources in each UE 115.

[0071] For example, in a group of five UEs 115, the group leader may inform one group member of the group identifier (e.g., group ID), group size (e.g., 5), and may assign a member ID (e.g., UE member ID=3). With this information, the V2X layer at the UE 115 may map the group ID to a destination layer 2 ID, which may be passed to the AS layer for action. At the same time, when generating the source layer 2 ID, the UE 115 may reflect the UE member ID in a subset of the bits of the source layer 2 ID (e.g., in the last 3 bits). Additionally, the group size (e.g., 5) is passed down to the AS layer. When the V2X layer configures the AS layer for a QoS flow for this V2X application, it will indicate that the QoS flow is for groupcast and will provide the corresponding QoS parameters (e.g., sidelink QoS identifier (PQI) and coverage for sidelink transmissions).

[0072] Upon receiving such information from the upper layer, the AS layer in the receiving UE 115 can act accordingly. For example, when the UE 115 needs to perform a transmission, a destination Layer 2 ID and a source Layer 2 ID may be retrieved based on the QoS flow ID (PFI) and the corresponding QoS context. In addition, the AS layer in the UE 115 may check the group size and determine whether a separate PSFCH resource should be used for each UE 115 to provide acknowledgement feedback. In some cases, a group size threshold may be configured (e.g., as part of the sidelink groupcast configuration) where group sizes below a threshold (e.g., 19 group members) have separate PSFCH resources and group sizes above the threshold use a common PSFCH resource. In cases where separate PSFCH resources are used for acknowledgement feedback, the AS layer in the UE 115 may derive a source Layer 1 ID from a source Layer 2 ID that reflects the member ID of the UE (e.g., may take the last 8 bits of the Layer 2 ID) and include the source Layer 1 ID in the sidelink control information (SCI).

[0073] Additionally, for a UE 115 in a group receiving a packet, such receiving UE 115 may also be informed of group size and UE member ID information related to the group at the AS layer. Thus, when a packet is received, the UE 115 may use the group size and its own UE member ID to derive a PSFCH resource to be used to provide acknowledgement feedback for the packet. For example, if the receiving UE 115 has member ID=5 and the transmitting UE 115 has member ID=3, the receiving UE 115 may infer the transmitting UE 115 member ID (member ID=3) using the group size (e.g., mod(Layer 1 ID, group size)) and may determine that a PSFCH resource indexed to 4 (i.e., receiving UE member ID>transmitting UE member ID, so receiving UE member ID-1) should be used. Thus, the group size and UE member ID information provided by the application layer in such a case allows separate feedback resources to be used at each member UE 115. In cases where the number of UEs 115 in a group is relatively large and exceeds a threshold, a common feedback resource may be used by multiple UEs in the group. In some cases, such actions may be estimated at each UE 115 by the group size provided in the SCI. In other cases, the type of feedback action may be explicitly indicated in the SCI when the transmission is performed.

[0074] 3 illustrates an example of a UE protocol stack 300 supporting a sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. In some examples, the UE protocol stack 300 may implement aspects of the wireless communication systems 100 or 200. In this example, a first UE 115-d may communicate with a second UE 115-e in a sidelink groupcast group. Each of the first UE 115-d and the second UE 115-e includes an application layer 305, an optional midware layer 310, a layer 2 315, and a layer 1 320.

[0075] In some cases, the Layer 1 320 and the Layer 2 315 may be referred to as AS layers. The Layer 1 320 may include a physical layer that provides a physical transport channel for over-the-air signals. The Layer 2 315 may include, for example, a Media Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, and a Service Data Adaptation Protocol (SDAP) layer. The optional midware layer 310 may include, for example, a group management midware layer that may distribute sidelink groupcast information to lower layers (e.g., the Layer 1 320 and the Layer 2 315). In other cases, the application layer 305 (e.g., the V2X application layer) may perform group management and distribute the sidelink groupcast information to lower layers. As described with reference to FIG. 2, in some cases, the source and destination Layer 2 IDs, as well as the Layer 1 ID, may be determined by each UE 115 and may be used to determine resources for groupcast communication and for acknowledgment feedback transmission.

[0076] 4 illustrates an example of a process flow 400 for supporting sidelink groupcast configuration to support feedback control, according to one or more aspects of the disclosure. In some examples, the process flow 400 may implement aspects of the wireless communication system 100 or 200. The process flow 400 may be implemented by a first UE 115-f, a second UE 115-g, or any other example of a UE 115 or base station 105 as described herein. Alternative examples of the following may be implemented, in which some steps are performed in a different order than described or not performed at all. In some cases, the steps may include additional features not mentioned below, or further steps may be added.

[0077] At 405, the first UE 115-f may determine sidelink groupcast parameters. In some cases, the first UE 115-f may be a group leader for sidelink groupcast communication (e.g., a platoon leader in V2X sidelink communication) and may identify several other UEs, including the second UE 115-g, as group members. In some examples, the UE 115-f may determine a member ID for the UE 115-f. In some cases, the first UE 115-f may determine a member ID for each UE 115 in the group as part of the determination of the sidelink groupcast parameters. Additionally, the first UE 115-f may determine a group ID associated with the sidelink groupcast communication group. In some cases, the sidelink groupcast parameters may be determined by a group management midware layer, at an application layer, or a combination thereof.

[0078] At 410, the first UE 115-f may determine a sidelink groupcast feedback configuration. In some cases, the first UE 115-f may identify acknowledgement feedback resources for use in providing the sidelink groupcast feedback. In some instances, the acknowledgement feedback resources may include separate resources for various UEs 115 of the sidelink groupcast communication group. Such an acknowledgement feedback resource configuration may be determined, for example, as described with reference to FIG. 2.

[0079] At 415, the first UE 115-f may transmit sidelink groupcast information to the second UE 115-g, where the sidelink groupcast information may include a group ID, a member ID of the second UE 115-g, a group size, and an optional feedback configuration indication (e.g., indicating common or separate feedback resources). In some cases, the sidelink groupcast information may be provided in an SCI transmitted to the second UE 115-g.

[0080] At 420, the first UE 115-f may determine UE identity information to be provided to a lower layer (e.g., AS layer). Similarly, at 425, the second UE 115-g may determine UE identity information to be provided to a lower layer (e.g., AS layer). In some cases, the UE identity information may include a source Layer 2 ID, a destination Layer 2 ID, a Layer 1 ID, or any combination thereof. Such UE identity information may be determined, for example, as described with reference to FIG. 2.

[0081] At 430, the first UE 115-f may transmit a sidelink communication to at least the second UE 115-g and one or more other UEs that may be included in the sidelink groupcast communication group. At 435, the second UE 115-g may receive and decode the sidelink communication and may generate an acknowledgement feedback (e.g., a HARQ ACK / NACK indication).

[0082] At 440, the second UE 115-g may determine feedback resources to be used for transmitting the acknowledgement feedback to the first UE 115-f. Such determination of the acknowledgement feedback resources may be performed, for example, as described with reference to FIG. 2. At 445, the second UE 115-g may transmit a feedback communication having the acknowledgement feedback to the first UE 115-f.

[0083] At 450, the first UE 115-f may determine whether to retransmit the sidelink communication based on the received feedback. In some cases, the first UE 115-f may determine to retransmit the sidelink communication based on receiving one or more NACKs from other UEs 115 in the group. Additionally or alternatively, the first UE 115-f may determine to retransmit the sidelink communication based on receiving acknowledgment feedback from fewer than all of the UEs 115 in the group (e.g., based on a group size of the sidelink groupcast communication group).

[0084] 5 illustrates a block diagram 500 of a device 505 supporting a sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the disclosure. The device 505 may be an example of an aspect of a UE 115 (e.g., a first UE or a second UE) 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).

[0085] 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 sidelink groupcast configuration to support feedback control, etc.). The information may be passed to other components of the device 505. The receiver 510 may be an example of an aspect of a transceiver 820 described with reference to FIG. 8. The receiver 510 may utilize a single antenna or a set of antennas.

[0086] The communications manager 515 may receive sidelink groupcast information of the first sidelink group from the second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE; determine an identity for communication with the first sidelink group based on the sidelink groupcast information at the first UE; and communicate with the first sidelink group based on the determined identity.

[0087] The communications manager 515 may also configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least the first UE and the second UE, determine a member identity of the first UE, determine a feedback resource configuration for the sidelink group based on a group size of the first sidelink group and the determined identity of the first UE, where the feedback resource configuration includes common feedback resources used by the plurality of members or separate feedback resources corresponding to each of the plurality of members, send sidelink groupcast information indicative of at least the feedback resource configuration to other members of the plurality of members of the first sidelink group, communicate with the first sidelink group based on the determined identity and the feedback resource configuration, and determine at the first UE an identity for communication with the first sidelink group based on the sidelink groupcast information. The communications manager 515 may be an example of an aspect of the communications manager 810 described herein.

[0088] The communications manager 515, or subcomponents thereof, may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 515, or subcomponents thereof, may be performed by a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0089] The communications manager 515 or its subcomponents may be physically located in various locations, including being distributed such that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, the communications manager 515 or its subcomponents may be separate and distinct components according to various aspects of the present disclosure. In some examples, the communications manager 515 or its subcomponents 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 this disclosure, or combinations thereof according to various aspects of the present disclosure.

[0090] The transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be co-located with the receiver 510 in a transceiver module. For example, the transmitter 520 may be an example of an embodiment of a transceiver 820 described with reference to FIG. 8. The transmitter 520 may utilize a single antenna or a set of antennas.

[0091] The communications manager 515 may be an example of a means for performing various aspects of the sidelink groupcast configuration as described herein. The communications manager 515 or its subcomponents may be implemented in hardware (e.g., communications manager circuitry). The circuitry may comprise a processor, DSP, ASIC, 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 this disclosure.

[0092] In another implementation, the communications manager 515 or its subcomponents may be implemented in code executed by a processor (e.g., as communications management software or firmware), or any combination thereof. When implemented in code executed by a processor, the functions of the communications manager 515 or its subcomponents may be performed by a general purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device.

[0093] In some examples, the communications manager 515 may be configured to perform various operations (e.g., receiving, determining, transmitting) using or otherwise cooperating with the receiver 510, the transmitter 520, or both.

[0094] In some examples, the communications manager 515 may be implemented as an integrated circuit or chipset for a mobile device modem, and the receiver 510 and transmitter 520 may be implemented as analog components (e.g., amplifiers, filters, antennas) coupled with the mobile device modem to enable wireless transmission and reception over one or more bands.

[0095] The communications manager 515 as described may be implemented to realize one or more potential advantages. One implementation may enable the device 505 to support feedback control for sidelink groupcast communications. Thus, the device 505 may determine device identity and feedback resources and may experience enhanced reliability and efficiency. In some examples, the device 505 may experience reduced power consumption and extended battery life, among other advantages.

[0096] 6 illustrates a block diagram 600 of a device 605 supporting a sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the disclosure. The device 605 may be an example of an aspect of a device 505 or a UE 115 (e.g., a first UE or a second UE) as described herein. The device 605 may include a receiver 610, a communications manager 615, and a transmitter 640. The device 605 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0097] 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 sidelink groupcast configuration to support feedback control, etc.). The information may be passed to other components of the device 605. The receiver 610 may be an example of an aspect of a transceiver 820 described with reference to FIG. 8. The receiver 610 may utilize a single antenna or a set of antennas.

[0098] The communications manager 615 may be an example of an aspect of the communications manager 515 as described herein. The communications manager 615 may include a sidelink configuration manager 620, an identification manager 625, a sidelink communications manager 630, and a feedback configuration manager 635. The communications manager 615 may be an example of an aspect of the communications manager 810 as described herein.

[0099] In some cases, the sidelink configuration manager 620 may receive sidelink groupcast information of the first sidelink group from the second UE, including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The identification manager 625 may determine an identity for communication with the first sidelink group based on the sidelink groupcast information. The sidelink communications manager 630 may communicate with the first sidelink group based on the determined identity.

[0100] In some cases, the sidelink configuration manager 620 may configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes multiple members including at least the first UE and the second UE. The feedback configuration manager 635 may determine a feedback resource configuration for the sidelink group based on a group size of the first sidelink group, where the feedback resource configuration includes common feedback resources used by the multiple members or separate feedback resources corresponding to each of the multiple members. The sidelink communications manager 630 may send sidelink groupcast information indicating at least the feedback resource configuration to other members of the multiple members of the first sidelink group and may communicate with the first sidelink group based on the determined identification information and the feedback resource configuration. The identification manager 625 may determine an identification information at the first UE for communication with the first sidelink group based on the sidelink groupcast information.

[0101] The transmitter 640 may transmit signals generated by other components of the device 605. In some examples, the transmitter 640 may be co-located with the receiver 610 in a transceiver module. For example, the transmitter 640 may be an example of an embodiment of the transceiver 820 described with reference to FIG. 8. The transmitter 640 may utilize a single antenna or a set of antennas.

[0102] 7 illustrates a block diagram 700 of a communications manager 705 supporting sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. The communications manager 705 may be an example of an aspect of the communications manager 515, communications manager 615, or communications manager 810 described herein. The communications manager 705 may include a sidelink configuration manager 710, an identification manager 715, a sidelink communications manager 720, an L2 ID manager 725, an L1 ID manager 730, a feedback configuration manager 735, a feedback decision manager 740, and a QoS flow manager 745. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0103] The sidelink configuration manager 710 may receive sidelink groupcast information for the first sidelink group from the second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. In some cases, the sidelink groupcast information further includes a group identifier of the first sidelink group.

[0104] In some examples, the sidelink configuration manager 710 may configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes multiple members including at least the first UE and the second UE. In some cases, the sidelink groupcast information is received at an application layer of the first UE or at a group management midware layer in the first UE. In some cases, the sidelink groupcast information further indicates a group identifier of the first sidelink group, a group size of the first sidelink group, and corresponding member identities within the first sidelink group of each of the multiple members.

[0105] The identification manager 715 may determine an identity at the first UE for communication with the first sidelink group based on the sidelink groupcast information. In some examples, the identification manager 715 may determine a member identity for the first UE.

[0106] The sidelink communications manager 720 may communicate with the first sidelink group based on the determined identity.

[0107] In some examples, the sidelink communications manager 720 may send sidelink groupcast information indicating at least the feedback resource configuration to other members of the plurality of members of the first sidelink group. In some examples, the sidelink communications manager 720 may communicate with the first sidelink group based on the determined identity and the feedback resource configuration.

[0108] The feedback configuration manager 735 may determine a feedback resource configuration for the sidelink group based on the group size of the first sidelink group and the member identity of the first UE, where the feedback resource configuration includes common feedback resources used by multiple members or separate feedback resources corresponding to each of the multiple members.

[0109] In some examples, the feedback configuration manager 735 may determine based on the group size of the first sidelink group whether each of the members of the first sidelink group uses separate feedback resources to provide acknowledgment feedback information to other of the members of the first sidelink group.

[0110] Possibly, the first UE decides whether separate or common feedback resources are used for providing the acknowledgement feedback information based on whether the number of members of the first sidelink group exceeds a threshold number of members. Possibly, separate feedback resources are used for providing the acknowledgement feedback information when the number of members of the first sidelink group is equal to or less than the threshold number of members. Possibly, common resources are used for providing the acknowledgement feedback information when the number of members of the first sidelink group exceeds the threshold number of members.

[0111] In some cases, the first UE determines whether separate or common feedback resources are used to provide the acknowledgement feedback information based on a pre-configuration of the first UE, a control signaling received from another UE or a base station, or any combination thereof. In some cases, the first UE determines whether separate or common feedback resources are used to provide the acknowledgement feedback information based on an RRC signaling received at the first UE, a SIB received at the first UE, a MAC control element received at the first UE, or any combination thereof. In some cases, the number of separate feedback resources corresponds to the number of members of the first sidelink group minus one.

[0112] The L2 ID manager 725 may manage Layer 2 identities of the UEs. In some cases, the identity is a destination Layer 2 identity, and a member identity of the first UE is included as a first subset of bits of the source Layer 2 identity. In some cases, a group identifier is mapped to a second subset of bits of the destination Layer 2 identity. In some cases, a number of bits of the first subset of bits is determined based on a group size of the first sidelink group. In some cases, the identity is a source Layer 2 identity, and an identity of the first UE is included as a first subset of bits of the source Layer 2 identity, and a group identifier is mapped to a second subset of bits of the destination Layer 2 identity. In some cases, a number of bits of the first subset of bits is determined based on a group size of the first sidelink group.

[0113] The L1 ID manager 730 may determine a Layer 1 identity based on the source Layer 2 identity, where the Layer 1 identity is indicated in the physical layer control information transmission for the first sidelink group. In some cases, the Layer 1 identity corresponds to a subset of the source Layer 2 identity that indicates a group identifier of the first sidelink group and a member identity of the first UE within the first sidelink group.

[0114] The feedback decision manager 740 may determine a set of feedback resources for transmitting acknowledgement feedback information to one or more members of the first sidelink group based at least in part on a group size of the first sidelink group and a member identity of the first UE within the first sidelink group.

[0115] In some examples, the feedback decision manager 740 may receive a first groupcast communication from a second UE. In some examples, the feedback decision manager 740 may determine acknowledgement feedback for the first groupcast communication. In some examples, the feedback decision manager 740 may transmit acknowledgement feedback for the first groupcast communication to the second UE using a set of feedback resources.

[0116] In some examples, the feedback decision manager 740 may send the groupcast communication to other members of the plurality of members of the first sidelink group. In some examples, the feedback decision manager 740 may determine to retransmit the groupcast communication based on acknowledgement feedback from at least one of the plurality of members of the first sidelink group.

[0117] In some examples, the feedback decision manager 740 may determine that at least one of the members of the first sidelink group provides a negative acknowledgement, determine that acknowledgement feedback from at least one of the members of the first sidelink group is not received at the first UE, or any combination thereof. In some examples, the feedback decision manager 740 may send a groupcast communication to other members of the members of the first sidelink group. In some examples, the feedback decision manager 740 may monitor for acknowledgement feedback from other members of the members of the first sidelink group based on a feedback resource configuration.

[0118] The QoS flow manager 745 may configure an access stratum layer in the first UE for a QoS flow for the groupcast communication associated with the Layer 2 identity, where the access stratum layer determines the QoS flow identity and QoS context and derives a Layer 1 identity for the QoS flow.

[0119] 8 illustrates a diagram of a system 800 including a device 805 supporting a sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the disclosure. The device 805 may be an example of or may include components of a device 505, a device 605, or a UE 115 as described herein. The device 805 may include components for two-way voice and data communication, including components for transmitting and receiving communications, including a communications manager 810, an I / O controller 815, a transceiver 820, an antenna 825, a memory 830, and a processor 840. These components may be in electronic communication over one or more buses (e.g., bus 845).

[0120] The communications manager 810 may receive sidelink groupcast information of the first sidelink group from the second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE; determine an identity for communication with the first sidelink group based on the sidelink groupcast information at the first UE; and communicate with the first sidelink group based on the determined identity.

[0121] The communications manager 810 may also configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least the first UE and the second UE; determine a member identity of the first UE; determine a feedback resource configuration for the sidelink group based on a group size of the first sidelink group and the determined member identity of the first UE, where the feedback resource configuration includes common feedback resources used by the plurality of members or separate feedback resources corresponding to each of the plurality of members; send sidelink groupcast information indicating at least the feedback resource configuration to other members of the plurality of members of the first sidelink group; communicate with the first sidelink group based on the determined identity and the feedback resource configuration; and determine at the first UE an identity for communication with the first sidelink group based on the sidelink groupcast information.

[0122] The I / O controller 815 may manage input and output signals for the device 805. The I / O controller 815 may also manage peripheral devices that are 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 device. In some cases, the I / O controller 815 may utilize an operating system, such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In other cases, the I / O controller 815 may represent or interact with a modem, keyboard, mouse, touch screen, or 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 through the I / O controller 815 or through hardware components controlled by the I / O controller 815.

[0123] The transceiver 820 may communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, the transceiver 820 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 820 may also include a modem for modulating packets for transmission and providing modulated packets to an antenna, and for demodulating packets received from the antenna.

[0124] In some cases, a wireless device may include a single antenna 825. In some cases, however, a device may have two or more antennas 825 that may be capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0125] The memory 830 may include random access memory (RAM) and read only memory (ROM). The memory 830 may store computer-readable computer-executable code 835 that includes instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 830 may include a basic input / output system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0126] The processor 840 may include intelligent hardware devices (e.g., a general purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, 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, the 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., memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks supporting sidelink group cast configuration to support feedback control).

[0127] The code 835 may include instructions for implementing aspects of the disclosure, including instructions for supporting wireless communications. The code 835 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 835 may not be directly executable by the processor 840, but may (e.g., when compiled and executed) cause a computer to perform functions described herein.

[0128] FIG. 9 illustrates a flow chart illustrating a method 900 for supporting sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. The operations of the method 900 may be performed by the UE 115 or components thereof as described herein. For example, the operations of the method 900 may be performed by a communications manager as described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described below.

[0129] At 905, the UE may receive sidelink groupcast information for a first sidelink group from a second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE within the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The operations of 905 may be performed according to methods described herein. In some examples, aspects of the operations of 905 may be performed by a sidelink configuration manager as described with reference to Figures 5-8.

[0130] At 910, the UE may determine an identity for communication with the first sidelink group based on the sidelink groupcast information. The operations of 910 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 910 may be performed by an identity manager such as those described with reference to FIGS. 5-8.

[0131] At 915, the UE may communicate with the first sidelink group based on the determined identity. The operations of 915 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 915 may be performed by a sidelink communications manager as described with reference to FIGS.

[0132] FIG. 10 illustrates a flow chart illustrating a method 1000 for supporting sidelink groupcast configuration to support feedback control according to one or more aspects of the present disclosure. The operations of method 1000 may be performed by the UE 115 or components thereof as described herein. For example, the operations of method 1000 may be performed by a communications manager as described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described below.

[0133] At 1005, the UE may receive sidelink groupcast information for a first sidelink group from a second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The operations of 1005 may be performed according to methods described herein. In some examples, aspects of the operations of 1005 may be performed by a sidelink configuration manager as described with reference to Figures 5-8.

[0134] At 1010, the UE may determine an identity for communication with the first sidelink group based on the sidelink groupcast information. The operations of 1010 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1010 may be performed by an identity manager as described with reference to FIGS. 5-8.

[0135] At 1015, the UE may communicate with the first sidelink group based on the determined identity. The operations of 1015 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1015 may be performed by a sidelink communications manager as described with reference to FIGS. 5-8.

[0136] At 1020, the UE may determine, based on a group size of the first sidelink group, whether each of the multiple members of the first sidelink group uses separate feedback resources to provide acknowledgement feedback information to other members of the multiple members of the first sidelink group. The operations of 1020 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1020 may be performed by a feedback configuration manager as described with reference to Figures 5-8.

[0137] FIG. 11 illustrates a flow chart illustrating a method 1100 for supporting sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. The operations of the method 1100 may be performed by the UE 115 or components thereof as described herein. For example, the operations of the method 1100 may be performed by a communications manager as described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described below.

[0138] At 1105, the UE may receive sidelink groupcast information for a first sidelink group from a second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE within the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The operations of 1105 may be performed according to methods described herein. In some examples, aspects of the operations of 1105 may be performed by a sidelink configuration manager as described with reference to Figures 5-8.

[0139] At 1110, the UE may determine an identity for communication with the first sidelink group based on the sidelink groupcast information. The operations of 1110 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1110 may be performed by an identity manager such as those described with reference to FIGS. 5-8.

[0140] At 1115, the UE may determine a set of feedback resources for transmitting acknowledgement feedback information to one or more members of the first sidelink group based at least in part on a group size of the first sidelink group and a member identity of the first UE within the first sidelink group. The operations of 1115 may be performed according to methods described herein. In some examples, aspects of the operations of 1115 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0141] At 1120, the UE may receive the first groupcast communication from the second UE. The operations of 1120 may be performed according to methods described herein. In some examples, aspects of the operations of 1120 may be performed by a feedback decision manager such as those described with reference to FIGS.

[0142] At 1125, the UE may determine an acknowledgement feedback for the first groupcast communication. The operations of 1125 may be performed according to methods described herein. In some examples, aspects of the operations of 1125 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0143] At 1130, the UE may transmit acknowledgement feedback for the first groupcast communication to the second UE using the set of feedback resources. The operations of 1130 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1130 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0144] FIG. 12 illustrates a flow chart illustrating a method 1200 for supporting sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. The operations of the method 1200 may be performed by the UE 115 or components thereof as described herein. For example, the operations of the method 1200 may be performed by a communications manager as described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described below.

[0145] At 1205, the UE may receive sidelink groupcast information for a first sidelink group from a second UE, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE in the first sidelink group, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The operations of 1205 may be performed according to methods described herein. In some examples, aspects of the operations of 1205 may be performed by a sidelink configuration manager as described with reference to Figures 5-8.

[0146] At 1210, the UE may determine an identity for communication with the first sidelink group based on the sidelink groupcast information. The operations of 1210 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1210 may be performed by an identity manager such as those described with reference to FIGS. 5-8.

[0147] At 1215, the UE may transmit a groupcast communication to other members of the plurality of members of the first sidelink group. The operations of 1215 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1215 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0148] At 1220, the UE may monitor for acknowledgement feedback from other members of the plurality of members of the first sidelink group. The operations of 1220 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1220 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0149] At 1225, the UE may determine to retransmit the groupcast communication based on the acknowledgement feedback from at least one of the plurality of members of the first sidelink group. The operations of 1225 may be performed according to methods described herein. In some examples, aspects of the operations of 1225 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0150] FIG. 13 illustrates a flow chart illustrating a method 1300 for supporting sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. The operations of the method 1300 may be performed by the UE 115 or components thereof as described herein. For example, the operations of the method 1300 may be performed by a communications manager as described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described below.

[0151] At 1305, the UE may configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The operations of 1305 may be performed according to methods described herein. In some examples, aspects of the operations of 1305 may be performed by a sidelink configuration manager as described with reference to FIGS. 5-8.

[0152] At 1310, the UE may determine a member identity for the first UE. The operations of 1310 may be performed according to methods described herein. In some examples, aspects of the operations of 1310 may be performed by an identity manager such as those described with reference to FIGS.

[0153] At 1315, the UE may determine a feedback resource configuration for the sidelink group based on a group size of the first sidelink group and the determined member identity of the first UE, where the feedback resource configuration includes common feedback resources used by multiple members or separate feedback resources corresponding to each of the multiple members. The operations of 1315 may be performed according to methods described herein. In some examples, aspects of the operations of 1315 may be performed by a feedback configuration manager as described with reference to Figures 5-8.

[0154] At 1320, the UE may transmit sidelink groupcast information indicating at least the feedback resource configuration to other members of the plurality of members of the first sidelink group. The operations of 1320 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1320 may be performed by a sidelink communications manager as described with reference to FIGS. 5-8.

[0155] At 1325, the UE may determine an identity for communication with the first sidelink group based on the sidelink groupcast information. The operations of 1325 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1325 may be performed by an identity manager as described with reference to FIGS. 5-8.

[0156] At 1330, the UE may communicate with the first sidelink group based on the determined identity and the feedback resource configuration. The operations of 1330 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1330 may be performed by a sidelink communications manager as described with reference to FIGS. 5-8.

[0157] FIG. 14 illustrates a flow chart illustrating a method 1400 for supporting sidelink groupcast configuration to support feedback control in accordance with one or more aspects of the present disclosure. The operations of the method 1400 may be performed by the UE 115 or components thereof as described herein. For example, the operations of the method 1400 may be performed by a communications manager as described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described below.

[0158] At 1405, the UE may configure a first sidelink group for sidelink groupcast communication, where the first sidelink group includes a plurality of members including at least the first UE and the second UE. The operations of 1405 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1405 may be performed by a sidelink configuration manager as described with reference to FIGS. 5-8.

[0159] At 1410, the UE may determine a member identity for the first UE. The operations of 1410 may be performed according to methods described herein. In some examples, aspects of the operations of 1410 may be performed by an identity manager such as those described with reference to FIGS.

[0160] At 1415, the UE may determine a feedback resource configuration for the sidelink group based on a group size of the first sidelink group, where the feedback resource configuration includes common feedback resources used by multiple members or separate feedback resources corresponding to each of the multiple members. The operations of 1415 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1415 may be performed by a feedback configuration manager as described with reference to FIGS. 5-8.

[0161] At 1420, the UE may transmit sidelink groupcast information indicating at least the feedback resource configuration to other members of the plurality of members of the first sidelink group. The operations of 1420 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1420 may be performed by a sidelink communications manager as described with reference to FIGS. 5-8.

[0162] At 1425, the UE may determine an identity for communication with the first sidelink group based on the sidelink groupcast information. The operations of 1425 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1425 may be performed by an identity manager as described with reference to FIGS. 5-8.

[0163] At 1430, the UE may transmit a groupcast communication to other members of the plurality of members of the first sidelink group. The operations of 1430 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1430 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0164] At 1435, the UE may monitor for acknowledgement feedback from other members of the plurality of members of the first sidelink group based on the feedback resource configuration. The operations of 1435 may be performed according to methods described herein. In some examples, aspects of the operations of 1435 may be performed by a feedback decision manager as described with reference to Figures 5-8. In some cases, separate feedback resources are used to provide acknowledgement feedback information when the number of members of the plurality of members of the first sidelink group is less than or equal to a threshold number of members. In some cases, common resources are used to provide acknowledgement feedback information when the number of members of the plurality of members of the first sidelink group exceeds the threshold number of members.

[0165] At 1440, the UE may determine to retransmit the groupcast communication based on the acknowledgement feedback from at least one of the plurality of members of the first sidelink group. The operations of 1440 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1440 may be performed by a feedback decision manager as described with reference to FIGS. 5-8.

[0166] The following provides a summary of embodiments of the present disclosure. EXAMPLES

[0167] A method for wireless communication in a first UE, comprising: receiving from a second UE sidelink groupcast information of a first sidelink group, the sidelink groupcast information including a group size of the first sidelink group and a member identity of the first UE within the first sidelink group, the first sidelink group including a plurality of members including at least the first UE and the second UE; determining at the first UE an identity for communication with the first sidelink group based at least in part on the sidelink groupcast information; and communicating with the first sidelink group based at least in part on the determined identity. EXAMPLES

[0168] The method of example 1, further comprising each of a plurality of members of the first sidelink group determining whether to use a separate feedback resource for providing acknowledgement feedback information to other members of the plurality of members of the first sidelink group based at least in part on a group size of the first sidelink group. EXAMPLES

[0169] In a second embodiment of the method, the first UE determines whether separate feedback resources or a common feedback resource is used to provide acknowledgement feedback information based at least in part on whether a number of the plurality of members of the first sidelink group exceeds a threshold number of members. EXAMPLES

[0170] In a method of Example 2, the first UE determines whether a separate feedback resource or a common feedback resource is used to provide acknowledgement feedback information based at least in part on a pre-configuration of the first UE, control signaling received from another UE or a base station, or any combination thereof. EXAMPLES

[0171] In a method of Example 2, the first UE determines whether a separate feedback resource or a common feedback resource is used to provide acknowledgement feedback information based at least in part on RRC signaling received at the first UE, a SIB received at the first UE, a MAC control element received at the first UE, or any combination thereof. EXAMPLES

[0172] The method according to any one of the first to fifth embodiments, wherein the identity is a source Layer 2 identity, and the member identity of the first UE is included as a first subset of bits of the source Layer 2 identity. EXAMPLES

[0173] In any one of the first to sixth embodiments, the sidelink groupcast information further includes a group identifier of the first sidelink group. EXAMPLES

[0174] 8. The method of embodiment 7, wherein the group identifier is mapped to a second subset of bits of the destination Layer 2 identity. EXAMPLES

[0175] The method of any of Examples 6 to 8, further comprising determining a Layer 1 identity based at least in part on the source Layer 2 identity, wherein the Layer 1 identity is indicated in a physical layer control information transmission for the first sidelink group. EXAMPLES

[0176] 10. The method of example 9, wherein the Layer 1 identity corresponds to a subset of the source Layer 2 identity indicating a membership identity of the first UE within the first sidelink group. EXAMPLES

[0177] 9. The method according to any one of embodiments 6-8, wherein a number of bits of the first subset of bits is determined based at least in part on a group size of the first sidelink group. EXAMPLES

[0178] The method of any of Examples 1-11, further comprising determining a set of feedback resources for transmitting acknowledgement feedback information to one or more members of the first sidelink group based at least in part on a group size of the first sidelink group and a member identity of the first UE within the first sidelink group. EXAMPLES

[0179] The method of Example 12, further comprising: receiving a first groupcast communication from a second UE; determining an acknowledgement feedback for the first groupcast communication; and transmitting the acknowledgement feedback for the first groupcast communication to the second UE using the set of feedback resources. EXAMPLES

[0180] The method of any of the first to thirteenth embodiments further comprises: sending a groupcast communication to other members of the plurality of members of the first sidelink group; monitoring for and obtaining acknowledgment feedback from other members of the plurality of members of the first sidelink group; and determining to retransmit the groupcast communication based at least in part on the acknowledgment feedback from at least one of the plurality of members of the first sidelink group. EXAMPLES

[0181] In the method of example 14, determining to retransmit further comprises determining that at least one of the plurality of members of the first sidelink group provides a negative acknowledgement, determining that no acknowledgement feedback from at least one of the plurality of members of the first sidelink group is received at the first UE, or any combination thereof. EXAMPLES

[0182] A method according to any one of the first to fifteenth embodiments, further comprising configuring an access stratum layer in the first UE for a QoS flow for groupcast communication associated with the Layer 2 identification, the access stratum layer determining a QoS flow identification and a QoS context, and deriving a Layer 2 identification for the QoS flow. EXAMPLES

[0183] In any of the methods according to embodiments 1 to 16, the sidelink groupcast information is received at an application layer of the first UE or at a group management midware layer in the first UE. EXAMPLES

[0184] A method for wireless communication in a first UE, comprising: configuring a first sidelink group for sidelink groupcast communication, the first sidelink group including a plurality of members including at least a first UE and a second UE; determining a member identity of the first UE; determining a feedback resource configuration for the sidelink group based at least in part on a group size of the first sidelink group and the determined member identity of the first UE; transmitting sidelink groupcast information indicative of at least the feedback resource configuration to other members of the plurality of members of the first sidelink group; determining an identity at the first UE for communication with the first sidelink group based at least in part on the sidelink groupcast information; and communicating with the first sidelink group based at least in part on the determined identity and the feedback resource configuration. EXAMPLES

[0185] 19. The method of example 18, wherein the feedback resource configuration includes a common feedback resource used by multiple members or a separate feedback resource corresponding to each of the multiple members. EXAMPLES

[0186] A method of example 19, wherein a separate feedback resource is used for providing acknowledgement feedback information when the number of members of the first sidelink group is less than or equal to a threshold number of members, and a common resource is used for providing acknowledgement feedback information when the number of members of the first sidelink group exceeds the threshold number of members. EXAMPLES

[0187] The method of any of Examples 19 or 20, further comprising: sending a groupcast communication to other members of the plurality of members of the first sidelink group; monitoring for acknowledgement feedback from other members of the plurality of members of the first sidelink group based at least in part on the feedback resource configuration; and determining to retransmit the groupcast communication based at least in part on the acknowledgement feedback from at least one of the plurality of members of the first sidelink group. EXAMPLES

[0188] In the method of example 21, determining to retransmit further comprises determining that at least one of the multiple members of the first sidelink group provides a negative acknowledgement, determining that no acknowledgement feedback from at least one of the multiple members of the first sidelink group is received at the first UE, or any combination thereof. EXAMPLES

[0189] In any of the methods of Examples 18-22, the first UE determines whether a separate feedback resource or a common feedback resource is used to provide the acknowledgement feedback information based at least in part on a pre-configuration of the first UE, a control signaling received from another UE or a base station, or any combination thereof. EXAMPLES

[0190] In any of the methods of Examples 18 to 22, the first UE determines whether separate feedback resources or common feedback resources are used to provide acknowledgement feedback information based at least in part on RRC signaling received at the first UE, a SIB received at the first UE, a MAC control element received at the first UE, or any combination thereof. EXAMPLES

[0191] 25. The method according to any one of embodiments 18 to 24, wherein the number of separate feedback resources corresponds to the number of members of the first sidelink group minus one. EXAMPLES

[0192] The method of any of Examples 18 to 25, wherein the sidelink groupcast information further indicates a group identifier of the first sidelink group, a group size of the first sidelink group, and corresponding member identification information within the first sidelink group for each of the plurality of members. EXAMPLES

[0193] 26. The method of claim 26, wherein the identity is a source Layer 2 identity, the identity of the first UE is included as a first subset of bits of the source Layer 2 identity, and the group identifier is mapped to a second subset of bits of the destination Layer 2 identity. EXAMPLES

[0194] The method of Example 27, further comprising determining a Layer 1 identity based at least in part on the source Layer 2 identity, the Layer 1 identity being indicated for the first sidelink group in a physical layer control information transmission. EXAMPLES

[0195] 29. The method of Example 28, wherein the layer 1 identity corresponds to a subset of the source layer 2 identity. EXAMPLES

[0196] An apparatus for wireless communication comprising: a processor; and a memory coupled to the processor, wherein the processor and the memory are configured to perform the method of any one of Examples 1-17. EXAMPLES

[0197] An apparatus for wireless communication comprising: a processor; and a memory coupled to the processor, wherein the processor and the memory are configured to perform the method of any one of Examples 18 to 29. EXAMPLES

[0198] An apparatus for wireless communication, comprising at least one means for performing the method of any one of Examples 1 to 17. EXAMPLES

[0199] An apparatus for wireless communication, comprising at least one means for performing the method of any one of Examples 18 to 29. EXAMPLES

[0200] A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform a method according to any one of Examples 1 to 17. EXAMPLES

[0201] A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of any one of Examples 18-29.

[0202] It should be noted that the methods described herein represent possible implementations, that acts and steps may be rearranged or otherwise modified, and that other implementations are possible. Additionally, aspects from two or more of the methods may be combined.

[0203] The techniques described herein may be used for various wireless communication systems, such as CDMA systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, OFDMA systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and other systems. CDMA systems may implement radio technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 releases are sometimes commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA), and other variants of CDMA. TDMA systems may implement radio technologies such as Global System for Mobile Communications (GSM).

[0204] An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Enhanced UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein may be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. Aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described as examples, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used throughout much of the description, although the techniques described herein are applicable to other than LTE, LTE-A, LTE-A Pro, or NR applications.

[0205] A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with a service subscription with the network provider. A small cell may be associated with a lower power base station compared to a macro cell, and the small cell may operate in the same or different frequency bands (e.g., licensed frequency bands, unlicensed frequency bands, etc.) as the macro cell. Small cells may include pico cells, femto cells, and micro cells, according to various examples. A pico cell may, for example, cover a small geographic area and allow unrestricted access by UEs with a service subscription with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs with an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in the home, etc.). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (eg, two, three, four, etc.) cells and may also support communication using one or multiple component carriers.

[0206] The wireless communications systems described herein may support synchronous or asynchronous operation. For synchronous operation, base stations may have similar frame timing and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, base stations may have different frame timing and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operation.

[0207] The information and signals described herein may be represented using any of a wide variety of technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0208] The various example blocks and modules described in connection with the disclosure herein may be implemented or performed using a general purpose processor, a DSP, an ASIC, 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 alternatively, the processor may be any conventional 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).

[0209] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features implementing the functions may also be physically located in various locations, including being distributed such that portions of the functions are implemented in different physical locations.

[0210] 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. Non-transitory storage media may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, 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 can be used to carry or store desired program code means in the form of instructions or data structures and that can 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 coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of media. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable media.

[0211] As used herein, including within the claims, "or" as used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such as, 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, the phrase "based on" as used herein should not be interpreted as a reference to a closed set of conditions. For example, an exemplary step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, the phrase "based on" as used herein is to be interpreted in the same manner as the phrase "based at least in part on."

[0212] In the accompanying figures, similar components or features may have the same reference label. Furthermore, various components of the same type may be distinguished by following the reference label with a dash and a second label that distinguishes the similar components. If only a first reference label is used in this specification, the description is applicable to any of the similar components having the same first reference label, regardless of the second reference label, or other subsequent reference labels.

[0213] The description set forth herein with respect to the accompanying drawings describes exemplary configurations and does not necessarily represent all examples that may be implemented or fall within the scope of the claims. As used herein, the term "exemplary" means "serving as an example, instance, or illustration" and does not mean "preferred" or "advantageous over other examples." The detailed description includes specific details for the purposes of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0214] The description herein is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications of the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. [Explanation of symbols]

[0215] 100 Wireless communication system 102 UE Communication Manager 105 Base station 110 Coverage Area 115 User Equipment (UE) 120 backhaul links 125 Communication Links 130 Core Network 135 Communication Links 140 Sidelink communication link 200 Wireless Communication System 205 Side Link 210 Group 225 Access Link 300 UE Protocol Stack 305 Application Layer 310 Midware Layer 315 Layer 2 320 Layer 1 505 Devices 510 Receiver 515 Communications Manager 520 Transmitter 605 Devices 610 Receiver 615 Communications Manager 620 Sidelink Configuration Manager 625 Identity Manager 630 Sidelink Communications Manager 635 Feedback Configuration Manager 640 Transmitter 705 Communications Manager 710 Sidelink Configuration Manager 715 Identity Manager 720 Sidelink Communications Manager 725 L2 ID Manager 730 L1 ID Manager 735 Feedback Configuration Manager 740 Feedback Decision Manager 745 QoS Flow Manager 800 Systems 805 Devices 810 Communications Manager 815 I / O Controller 820 Transceiver 825 Antenna 830 Memory 835 Computer Executable Code 840 Processor 845 Bus

Claims

1. 1. A method for wireless communication in a first user equipment (UE), comprising: receiving sidelink groupcast information of a first sidelink group, the sidelink groupcast information including a group size of the first sidelink group and a membership identity of the first UE in the first sidelink group, the first sidelink group including at least the first UE and a second UE; determining, at the first UE, an identity for communication with the first sidelink group; determining a type of feedback action corresponding to common feedback resources used by a plurality of members of the first sidelink group based at least in part on the number of members of the first sidelink group exceeding a threshold number of members, based at least in part on the group size of the first sidelink group; communicating with the first sidelink group based at least in part on the determined identity. A method for providing the above.

2. determining, based at least in part on the group size of the first sidelink group, whether the type of feedback action corresponds to a separate feedback resource for providing acknowledgement feedback information. The method of claim 1 , further comprising:

3. determining, based at least in part on the number of members of the first sidelink group being less than a threshold number of members, whether the type of feedback action corresponds to a separate feedback resource for providing the acknowledgement feedback information. The method of claim 2 , further comprising:

4. 2. The method of claim 1, wherein the identity is a source Layer 2 identity, and the member identity of the first UE is included as a first subset of bits of the source Layer 2 identity.

5. The method of claim 4, wherein the sidelink groupcast information further comprises a group identifier of a first sidelink group.

6. The method of claim 5, wherein the group identifier is mapped to a second subset of bits of a destination Layer 2 identity.

7. determining a Layer 1 identity based at least in part on the source Layer 2 identity, wherein the Layer 1 identity is indicated in a physical layer control information transmission for the first sidelink group. The method of claim 4.

8. 8. The method of claim 7, wherein the Layer 1 identity corresponds to the first subset of bits of the source Layer 2 identity that is indicative of the member identity of the first UE within the first sidelink group.

9. 5. The method of claim 4, wherein a number of bits of the first subset of bits is determined based at least in part on the group size of the first sidelink group.

10. determining a set of feedback resources for transmitting acknowledgement feedback information to one or more members of the first sidelink group based at least in part on the group size of the first sidelink group and the member identity of the first UE within the first sidelink group. The method of claim 1 , further comprising:

11. receiving a first groupcast communication from the second UE; determining an acknowledgement feedback for the first groupcast communication; transmitting the acknowledgement feedback for the first groupcast communication to the second UE using the set of feedback resources; The method of claim 10, further comprising:

12. transmitting a groupcast communication to other members of the plurality of members of the first sidelink group; - monitoring for acknowledgment feedback from the other members of the plurality of members of the first sidelink group; determining, based at least in part on the acknowledgment feedback from at least one of the plurality of members of the first sidelink group, to retransmit the groupcast communication; The method of claim 1 , further comprising:

13. 2. The method of claim 1, further comprising: configuring an access stratum layer at the first UE for a quality of service (QoS) flow for groupcast communication associated with a Layer 2 identity.

14. An apparatus for wireless communication in a first user equipment (UE), comprising: means for receiving sidelink groupcast information of a first sidelink group, the sidelink groupcast information including a group size of the first sidelink group and a membership identity of the first UE in the first sidelink group, the first sidelink group including at least the first UE and a second UE; means for determining, at the first UE, an identity for communication with the first sidelink group; means for determining a type of feedback action corresponding to common feedback resources used by a plurality of members of the first sidelink group based at least in part on the number of members of the first sidelink group exceeding a threshold number of members, based at least in part on the group size of the first sidelink group; means for communicating with the first sidelink group based at least in part on the determined identity; and An apparatus comprising:

15. A computer program comprising instructions which, when executed on at least one processor of an apparatus for wireless communication, cause said apparatus to perform the method according to any one of claims 1 to 13.

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