Techniques for handling multicast feedback communications

Abstract

Methods, systems, and devices are described for wireless communication. The techniques described herein provide a technique for a transmitting user equipment (TX UE) to handle groupcast feedback communications by starting a groupcast communication using mode one groupcast feedback and changing to mode two groupcast feedback based on a metric of retransmissions exceeding a threshold. For example, the TX UE can transmit control signaling indicating mode one groupcast feedback. The TX UE can transmit a plurality of groupcast messages and can receive one or more NACK feedback messages associated with the plurality of groupcast messages. The TX UE can perform one or more retransmissions of the groupcast messages based on the received NACK feedback messages. If a metric of the one or more retransmissions exceeds a threshold number, the TX UE can transmit second control signaling indicating the mode two groupcast feedback.

Description

Cross-referencing

[0001] This patent application claims the benefit of U.S. Patent Application No. 18 / 505,953, filed November 9, 2023, entitled “TECHNIQUES FORHANDLING GROUPCAST ​​FEEDBACK COMMUNICATION”, which is assigned to the assignee of this application and is expressly incorporated herein by reference. Technical Field

[0002] The following relates to wireless communication, including techniques for handling multicast feedback communication. Background Technology

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, message sending and receiving, and broadcasting. These systems can support 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) systems, LTE-A Advanced (LTE-A) systems, or LTE-A Pro systems) and fifth-generation (5G) systems (which may be referred to as New Radio (NR) systems). These systems may employ technologies such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), or Discrete Fourier Transform Extended Orthogonal Frequency Division Multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations, each supporting wireless communication for communication devices, which may be referred to as User Equipment (UE). Summary of the Invention

[0004] The described technology relates to improved methods, systems, devices, and apparatuses for handling multicast feedback communications. For example, the described technology specifies that a transmitting user equipment (TX UE) handles multicast feedback communications by: initiating multicast communication using mode 1 multicast feedback; and changing to mode 2 multicast feedback by means of a retransmission metric exceeding a threshold. For example, the TX UE may send control signaling indicating mode 1 multicast feedback. The TX UE may send multiple multicast messages and may receive one or more NACK feedback messages associated with the multiple multicast messages. The TX UE may perform one or more retransmissions of the multicast messages based on the received NACK feedback messages. If the metric for one or more retransmissions exceeds a threshold number, the TX UE may send a second control signaling indicating mode 2 multicast feedback. The metric for one or more retransmissions may include a block error rate of one or more retransmissions or the number of one or more retransmissions.

[0005] A method for wireless communication by a first UE is described. The method may include: transmitting a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback; transmitting a set of multiple multicast messages, each multicast message in the set including a corresponding transport block; receiving one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages according to the first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of the corresponding transport block was unsuccessful; performing one or more retransmissions of the one or more multicast messages in the set of multiple multicast messages based on the one or more NACK feedback messages; and transmitting a second control signaling indicating a second mode of multicast feedback based on a metric of the one or more retransmissions exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0006] A first UE for wireless communication is described. The first UE may include one or more memories storing processor-executable code, and one or more processors coupled to the one or more memories. The one or more processors may be able to operate individually or jointly to execute the code to cause the first UE to: transmit a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback; transmit a set of multiple multicast messages, each of the multiple multicast messages including a corresponding transport block; receive one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages according to the first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of the corresponding transport block was unsuccessful; perform one or more retransmissions of the one or more multicast messages in the set of multiple multicast messages based on the one or more NACK feedback messages; and transmit a second control signaling indicating a second mode of multicast feedback based on a metric of the one or more retransmissions exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0007] Another first UE for wireless communication is described. The first UE may include: means for transmitting first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback; means for transmitting a set of multiple multicast messages, each multicast message in the set including a corresponding transport block; means for receiving one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages according to the first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of the corresponding transport block was unsuccessful; means for performing one or more retransmissions of the one or more multicast messages in the set of multiple multicast messages based on the one or more NACK feedback messages; and means for transmitting second control signaling indicating a second mode of multicast feedback based on a metric of the one or more retransmissions exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0008] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to: transmit a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback; transmit a set of multiple multicast messages, each of the multiple multicast messages including a corresponding transport block; receive, according to the first mode, one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of the corresponding transport block was unsuccessful; perform one or more retransmissions of the one or more multicast messages in the set of multiple multicast messages based on the one or more NACK feedback messages; and transmit a second control signaling indicating a second mode of multicast feedback based on a metric of the one or more retransmissions exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0009] In some examples of the methods described herein, the first UE, and the nontransitory computer-readable medium, sending the second control signaling may include operations, features, components, or instructions for sending the second control signaling based on the block error rate exceeding the first threshold.

[0010] In some examples of the methods described herein, the first UE, and non-transitory computer-readable media, the metric for the one or more retransmissions includes the number of the one or more NACK feedback messages.

[0011] The methods described herein, examples of the first UE, and some examples of nontransitory computer-readable media may also include operations, features, components, or instructions for: transmitting a second set of multiple multicast messages; receiving from the second UE, according to the second mode, one or more second NACK feedback messages associated with one or more multicast messages in the second set of multiple multicast messages; and transmitting the first mode indicating the multicast feedback.

[0012] The methods described herein, examples of the first UE, and some examples of non-transitory computer-readable media may also include operations, features, components, or instructions for: transmitting a third set of multiple multicast messages; receiving one or more third NACK feedback messages associated with one or more multicast messages in the third set of multiple multicast messages according to the first mode; and suppressing one or more retransmissions of one or more multicast messages in the third set of multiple multicast messages based on the one or more third NACK feedback messages.

[0013] The methods described herein, examples of the first UE, and some examples of non-transitory computer-readable media may also include operations, features, components, or instructions for: transmitting a third set of multiple multicast messages; receiving one or more third NACK feedback messages associated with one or more multicast messages in the third set of multiple multicast messages according to the first mode; and performing a fixed number of retransmissions of the one or more multicast messages in the third set of multiple multicast messages based on the one or more third NACK feedback messages.

[0014] The methods described herein, some examples of the first UE, and non-transitory computer-readable media may also include operations, features, components, or instructions for sending signaling to a third UE, a network entity, a vehicle networking application server, or any combination thereof, instructing the removal of the second UE from multicast communications.

[0015] The methods described herein, examples of the first user UE, and non-transitory computer-readable media may also include signaling for sending to a third UE, a network entity, a vehicle networking application server, or any combination thereof, indicating that the second UE may have violated the restrictions associated with the NACK feedback message. Attached Figure Description

[0016] Figure 1 An example of a wireless communication system supported by one or more aspects of this disclosure for handling multicast feedback communications is shown.

[0017] Figure 2 An example of a wireless communication system supported by one or more aspects of this disclosure for handling multicast feedback communications is shown.

[0018] Figure 3 An example of a wireless communication system supported by one or more aspects of this disclosure for handling multicast feedback communications is shown.

[0019] Figure 4 An example of a process flow supporting a technique for handling multicast feedback communications, according to one or more aspects of this disclosure, is shown.

[0020] Figure 5 and Figure 6 A block diagram of an apparatus supporting techniques for handling multicast feedback communications, according to one or more aspects of this disclosure, is shown.

[0021] Figure 7 A block diagram of a communication manager supporting techniques for handling multicast feedback communications, according to one or more aspects of this disclosure, is shown.

[0022] Figure 8 A diagram is shown of a system including an apparatus supporting techniques for handling multicast feedback communications, according to one or more aspects of this disclosure.

[0023] Figures 9 to 10 A flowchart illustrating a method for handling multicast feedback communication, according to one or more aspects of this disclosure, is shown. Detailed Implementation

[0024] In multicast sidelink communication, a transmitting (TX) user equipment (UE) can send a multicast message including a transport block to one or more receiving (RX) UEs. In some cases, multicast communication has two options for sidelink Hybrid Automatic Repeat Request (HARQ) feedback, referred to as Mode 1 and Mode 2. In Mode 1 (e.g., Option 1) multicast feedback, if the transport block is not successfully decoded, the RX UE can send a negative acknowledgment (NACK) feedback message, and if the transport block is successfully decoded, the RX UE can suppress (e.g., not send) an acknowledgment (ACK) feedback message. In Mode 2 (e.g., Option 2) multicast feedback, if the transport block is successfully decoded, the RX UE can send an ACK feedback message, and if the transport block is not successfully decoded, the RX UE can send a NACK feedback message.

[0025] In Mode 1 multicast feedback, the TX UE may not be able to identify which UE is transmitting a NACK feedback message. If, in Mode 1 multicast feedback, the TX UE receives at least one NACK feedback message corresponding to a transmitted multicast message, the TX UE may retransmit the multicast message. In Mode 1 multicast feedback, if one of the RX UEs repeatedly transmits a NACK feedback message for a multicast message, the TX UE may continue to retransmit the multicast message, thus consuming resources. In some cases, the RX UE may have equipment malfunctions leading to NACK feedback messages, or a malicious UE may intentionally transmit NACK feedback messages to congest resources.

[0026] To address potential duplicate NACK feedback messages and associated retransmissions, the TX UE can handle multicast feedback communication by initiating multicast communication using Mode 1 multicast feedback and switching to Mode 2 multicast feedback by exceeding a threshold based on a retransmission metric. For example, the TX UE can send control signaling indicating Mode 1 multicast feedback. The TX UE can send multiple multicast messages and receive one or more NACK feedback messages associated with the multiple multicast messages. The TX UE can perform one or more retransmissions of the multicast messages based on the received NACK feedback messages. If the metric for one or more retransmissions exceeds a threshold number, the TX UE can send a second control signaling indicating Mode 2 multicast feedback. Based on the received NACK feedback, the metric for one or more retransmissions may include the block error rate of one or more retransmissions or the number of retransmissions of one or more multicast messages.

[0027] The TX UE can send a second plurality of multicast messages and can receive one or more Mode 2 feedback messages (e.g., NACK or ACK feedback messages associated with one or more multicast messages in the second plurality of multicast messages). Using the Mode 2 multicast feedback message, the TX UE can identify one of the RX UEs transmitting duplicate NACK feedback messages. After identifying the RX UE transmitting duplicate NACK feedback messages, the TX UE can send control signaling indicating Mode 1 multicast feedback. When operating in Mode 1 multicast feedback, the TX UE can ignore the NACK feedback message, suppress retransmissions associated with the NACK feedback message, or remove the identified RX UE from multicast communications. Additionally, the TX UE can send messages indicating the presence of a malicious or faulty UE to other UEs, to network entities, or to a vehicle-to-everything (V2X) server.

[0028] The aspects of this disclosure are first described in the context of a wireless communication system. They are also described in the context of a process flow. The aspects of this disclosure are further illustrated and described by way of apparatus diagrams, system diagrams, and flowcharts relating to techniques for handling multicast feedback communication.

[0029] Figure 1 Examples of wireless communication systems 100 supporting techniques for handling multicast feedback communications according to one or more aspects of this disclosure are shown. Wireless communication system 100 may include one or more network entities 105, one or more UEs 115, and a core network 130. In some examples, wireless communication system 100 may be a Long Term Evolution (LTE) network, an Advanced LTE (LTE-A) network, an LTE-A Pro network, a New Radio (NR) network, or a network operating under other systems and radio technologies, including future systems and radio technologies not explicitly mentioned herein.

[0030] Network entity 105 may be distributed across a geographical area to form wireless communication system 100, and may include devices employing different forms or having different capabilities. In various examples, network entity 105 may be referred to as a network element, mobility element, radio access network (RAN) node, or network equipment, etc. In some examples, network entity 105 and UE 115 may wirelessly communicate via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, network entity 105 may support coverage area 110 (e.g., a geographical coverage area) within which UE 115 and network entity 105 may establish one or more communication links 125. Coverage area 110 may be an example of a geographical area within which network entity 105 and UE 115 may support the transmission of signals according to one or more radio access technologies (RATs).

[0031] UE 115 can be distributed throughout the coverage area 110 of wireless communication system 100, and each UE 115 can be stationary or mobile, or stationary and mobile at different times. UE 115 can be devices in different forms or with different capabilities. Figure 1 Some example UE 115s are illustrated herein. The UE 115 described herein can be able to support various types of devices (such as, e.g., ...). Figure 1 It communicates with other UEs (115 or network entity 105) as shown.

[0032] As described herein, a node in the wireless communication system 100 (which may be referred to as a network node or wireless node) may be a network entity 105 (e.g., any network entity described herein), a UE 115 (e.g., any UE described herein), a network controller, apparatus, device, computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described herein. For example, a node may be UE 115. As another example, a node may be network entity 105. As another example, a first node may be configured to communicate with a second node or a third node. In one aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be UE 115. In another aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be network entity 105. In other aspects of this example, the first node, the second node, and the third node may be different from these examples. Similarly, references to UE 115, network entity 105, device, equipment, computing system, etc., may include disclosures of UE 115, network entity 105, device, equipment, computing system, etc., as nodes. For example, a disclosure that UE 115 is configured to receive information from network entity 105 also discloses that a first node is configured to receive information from a second node.

[0033] In some examples, network entity 105 may communicate with core network 130, communicate with each other, or both. For example, network entity 105 may communicate with core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some examples, network entities 105 may communicate with each other directly (e.g., directly between network entities 105) or indirectly (e.g., via core network 130) via backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols). In some examples, network entities 105 may communicate with each other via midhaul communication link 162 (e.g., according to midhaul interface protocol) or fronthaul communication link 168 (e.g., according to fronthaul interface protocol) or any combination thereof. The backhaul communication link 120, midhaul communication link 162, or fronthaul communication link 168 may be one or more wired links (e.g., electrical links, fiber optic links), one or more wireless links (e.g., radio links, wireless optical links), etc., or various combinations thereof, or may include one or more wired links (e.g., electrical links, fiber optic links), one or more wireless links (e.g., radio links, wireless optical links), etc., or various combinations thereof. UE 115 may communicate with the core network 130 via communication link 155.

[0034] One or more network entities in network entity 105 described herein may include or be referred to as base station 140 (e.g., transceiver base station, radio base station, NR base station, access point, radio transceiver, node B, eNodeB (eNB), next-generation node B or gigabit node B (any of which may be referred to as gNB), 5G NB, next-generation eNB (ng-eNB), home node B, home evolution node B, or other suitable terms). In some examples, network entity 105 (e.g., base station 140) may be implemented in an aggregated (e.g., monolithic, standalone) base station architecture that may be configured to utilize a protocol stack that is physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as base station 140).

[0035] In some examples, network entity 105 may be implemented in a decomposed architecture (e.g., a decomposed base station architecture, a decomposed RAN architecture) that can be configured to utilize protocol stacks physically or logically distributed across two or more network entities 105, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, network entity 105 may include one or more of the following: a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN intelligent controller (RIC) 175 (e.g., a near real-time RIC, a non-real-time RIC), a service management and orchestration (SMO) 180 system, or any combination thereof. 170 may also be referred to as a radio headend, intelligent radio headend, remote radio headend (RRH), remote radio unit (RRU), or transmit / receive point (TRP). One or more components of network entity 105 in a decomposed RAN architecture may be co-located, or one or more components of network entity 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 in a decomposed RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0036] The functional splitting among CU 160, DU 165, and RU 170 is flexible and can support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof) are performed at CU 160, DU 165, or RU 170. For example, a protocol stack functional splitting can be used between CU 160 and DU 165, allowing CU 160 to support one or more layers of the protocol stack, and DU 165 to support one or more different layers of the protocol stack. In some examples, CU 160 can host higher protocol layer (e.g., Layer 3 (L3), Layer 2 (L2)) functionalities and signaling (e.g., Radio Resource Control (RRC), Serving Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP)). CU 160 can connect to one or more DU 165 or RU 170, and one or more DU 165 or RU 170 can host lower protocol layers, such as Layer 1 (L1) (e.g., Physical (PHY) layer) or L2 (e.g., Radio Link Control (RLC) layer, Medium Access Control (MAC) layer) functionality and signaling, and each can be at least partially controlled by CU 160. Additionally or alternatively, a protocol stack functional split can be employed between DU 165 and RU 170, such that DU 165 can support one or more layers of the protocol stack, and RU 170 can support one or more different layers of the protocol stack. DU 165 can support one or more different cells (e.g., via one or more RU 170). In some cases, functional decomposition between CU 160 and DU 165, or between DU 165 and RU 170, can be performed within the protocol layer (e.g., some functions of the protocol layer can be performed by one of CU 160, DU 165, or RU 170, while other functions of the protocol layer can be performed by different of CU 160, DU 165, or RU 170). CU 160 can be further functionally decomposed into CU control plane (CU-CP) functions and CU user plane (CU-UP) functions. CU 160 can be connected to one or more DU 165 via midhaul communication link 162 (e.g., F1, F1-c, F1-u), and DU 165 can be connected to one or more RU 170 via fronthaul communication link 168 (e.g., open fronthaul (FH) interface). In some examples, the midhaul communication link 162 or the fronthaul communication link 168 may be implemented based on the interfaces (e.g., channels) between the layers of the protocol stack, which are supported by the corresponding network entities 105 communicating via such communication links.

[0037] In a wireless communication system (e.g., wireless communication system 100), the infrastructure and spectrum resources for radio access can support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB node 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as donor entities or IAB donors. One or more DU 165s or one or more RU 170s may be partially controlled by one or more CU 160s associated with donor network entity 105 (e.g., donor base station 140). One or more donor network entities 105 (e.g., IAB donors) may communicate with one or more additional network entities 105 (e.g., IAB node 104) via supported access and backhaul links (e.g., backhaul communication link 120). IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a DU 165 of a coupled IAB donor. The IAB-MT may include a separate set of antennas for relaying communication with UE 115, or may share the same antennas (e.g., those of RU 170) for access to IAB node 104 via DU 165 of IAB node 104. (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, IAB node 104 may include a DU 165 that supports communication links with additional entities (e.g., IAB node 104, UE 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the decomposed RAN architecture (e.g., one or more IAB nodes 104 or components of IAB node 104) may be configured to operate according to the techniques described herein.

[0038] In the context of applying the techniques described herein to a decomposed RAN architecture, one or more components of the decomposed RAN architecture may be configured to support techniques for handling multicast feedback communications as described herein. For example, some operations described as being performed by UE 115 or network entity 105 (e.g., base station 140) may additionally or alternatively be performed by one or more components of the decomposed RAN architecture (e.g., IAB node 104, DU 165, CU 160, RU 170, RIC 175, SMO 180).

[0039] UE 115 may include or be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or any other suitable term, wherein "device" may also be referred to as a cell, station, terminal, or client, etc. UE 115 may also include or be referred to as a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, UE 115 may include or be referred to as a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or machine-type communication (MTC) device, etc., which may be implemented in various objects such as appliances or vehicles, meters, etc.

[0040] The UE 115 described herein can communicate with various types of devices, such as other UEs 115 that sometimes act as relays, network entities 105, and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, etc. Figure 1 As shown.

[0041] UE 115 and network entity 105 can wirelessly communicate with each other via one or more communication links 125 (e.g., access links) using resources associated with one or more carriers. The term "carrier" can refer to a set of RF spectrum resources having a defined physical layer structure for supporting communication link 125. For example, a carrier for communication link 125 may include a portion of the RF spectrum band (e.g., a bandwidth portion (BWP)) operating according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling coordinating carrier operation, user data, or other signaling. Wireless communication system 100 can support communication with UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, UE 115 can be configured using multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation can be used in conjunction with both frequency division duplex (FDD) component carriers and time division duplex (TDD) component carriers. Communication between network entity 105 and other devices can refer to communication between these devices and any part of network entity 105 (e.g., entity, sub-entity). For example, the terms “send,” “receive,” or “communicate” when referring to network entity 105 can refer to any part of the RAN’s network entity 105 (e.g., base station 140, CU160, DU 165, RU 170) communicating with another device (e.g., directly or via one or more other network entities 105).

[0042] The signal waveform transmitted via a carrier may include multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform extended OFDM (DFT-S-OFDM)). In a system employing MCM, a resource element may refer to a resource of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, in which case the symbol period and subcarrier spacing may be 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 decoding rate of the modulation scheme, or both), such that a relatively high number of resource elements (e.g., in the transmission duration) and a relatively high modulation scheme order correspond to a relatively high communication rate. Wireless communication resources may refer to a combination of RF spectrum resources, temporal resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial resources may increase the data rate or data integrity used for communication with UE 115.

[0043] The time interval for network entity 105 or UE 115 can be expressed as a multiple of a basic time unit, such as the sampling period. seconds, of which It can represent the supported subcarrier spacing, and This can represent the supported Discrete Fourier Transform (DFT) size. The time interval of the communication resources can be organized according to radio frames, each with a specified duration (e.g., 10 milliseconds (ms)). Each radio frame can be identified by a System Frame Number (SFN) (e.g., ranging from 0 to 1023).

[0044] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may (e.g., in the time domain) be divided into subframes, and each subframe may be further divided into a number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, time slots may be further divided into multiple micro-time slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., The duration of a symbol period is associated with a (number) sampling period. The duration of a symbol period can depend on the subcarrier spacing or the operating frequency band.

[0045] A subframe, time slot, micro-time slot, or symbol can be the smallest scheduling unit of the wireless communication system 100 (e.g., in the time domain) and can be referred to as a transmission time interval (TTI). In some examples, the duration of the TTI (e.g., the number of symbol periods in the TTI) can be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 can be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).

[0046] Depending on the technology, carriers can be used to multiplex physical channels for communication. One or more of Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), or hybrid TDM-FDM techniques can be used, for example, to multiplex physical control channels and physical data channels for signaling via a downlink carrier. The control region (e.g., control resource set (CORESET)) of the physical control channel can be defined by a set of symbol periods and can extend across the system bandwidth of the carrier or a subset of that bandwidth. One or more control regions (e.g., CORESET) can be configured for a set of UEs 115. For example, one or more UEs in UE 115 can monitor or search for control regions to obtain control information based on one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a concatenated manner. The aggregation level of control channel candidates can refer to the amount of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space set may include: a common search space set configured to transmit control information to multiple UEs 115, and a UE-specific search space set used to transmit control information to a specific UE 115.

[0047] In some examples, network entity 105 (e.g., base station 140, RU 170) may be mobile, and thus provide communication coverage to mobile coverage areas 110. In some examples, different coverage areas 110 associated with different technologies may overlap, but the different coverage areas 110 may be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of network entities 105 use the same or different radio access technologies to provide coverage for various coverage areas 110.

[0048] Wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, wireless communication system 100 may be configured to support ultra-reliable low-latency communication (URLLC). UE 115 may be designed to support ultra-reliable, low-latency, or critical functions. Ultra-reliable communication may include private or group communication and may be supported by one or more services, such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions may include prioritizing services, and such services may be used for public safety or general business applications. The terms “ultra-reliable,” “low-latency,” and “ultra-reliable low-latency” are used interchangeably herein.

[0049] In some examples, UE 115 may be configured to support direct communication with other UE 115s via device-to-device (D2D) communication link 135 (e.g., according to peer-to-peer (P2P), D2D, or sidelink protocols). In some examples, one or more UE 115s performing D2D communication in a group may be within the coverage area 110 of network entity 105 (e.g., base station 140, RU 170), which may support aspects of such D2D communication configured (e.g., scheduled by network entity 105). In some examples, one or more UE 115s in this group may be outside the coverage area 110 of network entity 105, or may otherwise be unable or not configured to receive transmissions from network entity 105. In some examples, the group of UE 115s communicating via D2D communication may support a one-to-many (1:M) system, where each UE 115 transmits to each of the other UE 115s in the group. In some examples, network entity 105 may facilitate the scheduling of resources used for D2D communication. In other examples, D2D communication may be performed between UEs 115 without involving network entity 105.

[0050] In some systems, the D2D communication link 135 may be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, vehicles may communicate using vehicle-to-vehicle (V2X) communication, vehicle-to-vehicle (V2V) communication, or a combination of these. Vehicles may signal information related to traffic conditions, signal control, weather, safety, emergencies, or any other information relevant to the V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure (such as roadside units), or communicate with the network via one or more network nodes (e.g., network entity 105, base station 140, RU 170) using vehicle-to-network (V2N) communication, or both.

[0051] Core network 130 provides user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. Core network 130 can 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), access and mobility management function (AMF)) for managing access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), packet data network (PDN) gateway (P-GW), or user plane function (UPF)) for routing packets or interconnecting to external networks. The control plane entity manages non-access stratum (NAS) functions, such as mobility, authentication, and bearer management of UE 115 served by network entity 105 (e.g., base station 140) associated with core network 130. User IP packets can be transferred through user plane entities, which provide IP address allocation and other functions. User plane entities can connect to one or more network operator IP services 150. IP services 150 may include access to the Internet, intranets, IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0052] Wireless communication system 100 can operate using one or more frequency bands in the range of 300 MHz to 300 GHz. Generally, the area from 300 MHz to 3 GHz is referred to as the Ultra High Frequency (UHF) band or decimeter band because the wavelength range is approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features (which may be referred to as clusters), but these waves are sufficient to penetrate structures so that macrocells can provide service to UE 115 located indoors. Compared to communication using smaller frequencies and longer wavelengths in the lower frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, communication using UHF waves can be associated with smaller antennas and shorter ranges (e.g., less than 100 km).

[0053] Wireless communication system 100 may utilize both licensed and unlicensed RF spectrum bands. For example, wireless communication system 100 may use unlicensed bands (such as the 5 GHz Industrial, Scientific, and Medical (ISM) band) to employ Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U) radio access technology, or NR technology. When operating with unlicensed RF spectrum, devices such as network entity 105 and UE 115 may employ carrier sensing for collision detection and avoidance. In some examples, operation using unlicensed bands may be combined with component carriers operating with licensed bands based on carrier aggregation configurations (e.g., LAA). Operation using unlicensed spectrum may include downlink transmission, uplink transmission, P2P transmission, or D2D transmission, etc.

[0054] Network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas that can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of network entity 105 or UE 115 may be located within one or more antenna arrays or antenna panels, which can support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly (such as an antenna tower). In some examples, the antennas or antenna arrays associated with network entity 105 may be located at different geographical locations. Network entity 105 may include an antenna array having a collection of multiple rows and columns of antenna ports that network entity 105 can use to support beamforming for communication with UE 115. Similarly, UE 115 may include one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals transmitted via the antenna ports.

[0055] Beamforming (also known as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting or receiving device (e.g., network entity 105, UE 115) to shape or guide an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting and receiving devices. Beamforming can be achieved by combining signals transmitted via antenna elements of an antenna array such that some signals propagating along a specific orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to the signals transmitted via the antenna elements may include applying amplitude shifts, phase shifts, or both to the signals carried via the antenna elements associated with the device. The adjustments associated with each of these antenna elements may be defined by a beamforming weight set associated with a specific orientation (e.g., relative to the antenna array of the transmitting or receiving device or relative to some other orientation).

[0056] In multicast sidelink communication, TX UE 115 can send multicast messages including transport blocks to one or more RX UE 115s. Multicast communication has two options for sidelink HARQ feedback. In Mode 1 (e.g., or Option 1) multicast feedback, if the transport block is not successfully decoded, the RX UE 115 can send a NACK feedback message, and if the transport block is successfully decoded, the RX UE can suppress (e.g., not send) an ACK feedback message. In Mode 2 (e.g., or Option 2) multicast feedback, if the transport block is successfully decoded, the RX UE 115 can send an ACK feedback message, and if the transport block is not successfully decoded, the RX UE can send a NACK feedback message.

[0057] In Mode 1 multicast feedback, if TX UE 115 receives at least one NACK feedback message corresponding to the transmitted multicast message, TX UE 115 may retransmit the multicast message. In Mode 1 multicast feedback, if one of RX UEs 115 repeatedly transmits a NACK feedback message for a multicast message, TX UE 115 may continue to retransmit the multicast message, thereby consuming resources. In some cases, RX UE 115 may have equipment malfunctions leading to NACK feedback messages, or a malicious UE may intentionally transmit NACK feedback messages to congest resources (e.g., it could be a malicious UE).

[0058] To address potential duplicate NACK feedback messages and associated retransmissions, the TX UE 115 can handle multicast feedback communication by initiating multicast communication using Mode 1 multicast feedback and changing to Mode 2 multicast feedback by adjusting the retransmission metric based on a threshold. For example, the TX UE 115 can send control signaling indicating Mode 1 multicast feedback. The TX UE 115 can send multiple multicast messages and receive one or more NACK feedback messages associated with the multiple multicast messages. The TX UE 115 can perform one or more retransmissions of the multicast messages based on the received NACK feedback messages. If the metric for one or more retransmissions exceeds a threshold number, the TX UE 115 can send a second control signaling indicating Mode 2 multicast feedback. The metric for one or more retransmissions may include the block error rate of one or more retransmissions or the number of one or more retransmissions.

[0059] TX UE 115 can send a second plurality of multicast messages and can receive one or more Mode 2 feedback messages (e.g., NACK or ACK feedback messages associated with one or more multicast messages in the second plurality of multicast messages). Using the Mode 2 multicast feedback message, TX UE can identify one of the RX UEs 115 that is transmitting duplicate NACK feedback messages. After identifying the RX UE 115 that is transmitting duplicate NACK feedback messages, TX UE 115 can send control signaling indicating Mode 1 first-order multicast feedback. When operating in Mode 1 first-order multicast feedback, TX UE 115 can ignore NACK feedback messages, suppress retransmissions associated with NACK feedback messages, or remove the identified RX UE 115 from multicast communications. Additionally, TX UE 115 can send messages indicating the presence of a malicious or faulty UE to other UEs 115, to network entity 105, or to a vehicle-to-everything (V2X) server.

[0060] Figure 2 An example of a wireless communication system 200 supporting techniques for handling multicast feedback communications according to one or more aspects of this disclosure is shown. The wireless communication system 200 may implement, or be implemented by, aspects of the wireless communication system 100. For example, the wireless communication system 200 may include UE 115-a, UE 115-b, and UE 115-c, which may be examples of UE 115 as described herein. The wireless communication system 200 may also include network entity 105-a, which may be an example of network entity 105 as described herein. The wireless communication system 200 may also include a V2X server 205.

[0061] UE 115-a can communicate with network entity 105-a using communication link 125-a. Communication link 125-a can be an example of an NR or LTE link between UE 115-a and network entity 105-a. Communication link 125-a can include a bidirectional link that enables both uplink and downlink communication. For example, UE 115-a can use communication link 125-a to send uplink signals (e.g., uplink transmissions), such as uplink control signals or uplink data signals, to network entity 105-a, and network entity 105-a can use communication link 125-a to send downlink signals (e.g., downlink transmissions), such as downlink control signals or downlink data signals, to UE 115-a. In some examples, UE115-a may send signaling 210 to network entity 105-a indicating that one of the UEs (e.g., UE 115-b, UE 115-c, or UE 115-d) has violated the restrictions associated with the NACK feedback message.

[0062] UE 115-a may communicate with V2X server 205 using communication link 135-a, which may be an example of communication link 135 as described herein. For example, communication link 135-a may be a sidelink communication link and may support bidirectional communication between V2X server 205 and UE 115-a. In some examples, UE 115-a may send signaling 215 to V2X server 205 indicating that one of the UEs (e.g., UE 115-b, UE 115-c, or UE 115-d) has violated the restrictions associated with the NACK feedback message. Alternatively, communication between UE 115-a and V2X server 205 may be conducted via network entity 105-a (e.g., the V2X server may be connected to network entity 105-a via one or more links).

[0063] UE 115-a can communicate with UE 115-b using communication link 135-b, which can be an example of communication link 135 as described herein. For example, communication link 135-a can be a sidelink communication link and can support bidirectional communication between UE 115-a and UE 115-b. In some examples, UE 115-a can send multicast message 220-a to UE 115-b, and UE 115-a can receive feedback message 225-a from UE 115-b. Similarly, UE 115-a can communicate with UE 115-c using communication link 135-c, which can be an example of communication link 135 as described herein. For example, communication link 135-c can be a sidelink communication link and can support bidirectional communication between UE 115-a and UE 115-c. In some examples, UE 115-a may send multicast message 220-b to UE 115-c, and UE 115-a may receive feedback message 225-b from UE 115-c. Similarly, UE 115-a may communicate with UE 115-d using communication link 135-d, which may be an example of communication link 135 as described herein. For example, communication link 135-d may be a sidelink communication link and may support bidirectional communication between UE 115-a and UE 115-d. In some examples, UE 115-a may send multicast message 220-c to UE 115-d, and UE 115-a may receive feedback message 225-c from UE 115-d. In some cases, messages 220-a, 220-b, and 220-c may be the same multicast message.

[0064] In some examples, UE 115-a may send a message to one of the UEs (e.g., UE 115-b, UE 115-c, or UE 115-d) in unicast (e.g., point-to-point communication from a TX UE to a specific RX UE). After unicast transmission, UE 115-a may wait for a HARQ feedback message from the RX UE. If the transport block is successfully received, the HARQ feedback message may include an ACK feedback message, and if the transport block is not successfully received, the HARQ feedback message may include a NACK feedback message.

[0065] Figure 3 Examples of wireless communication systems 300 supporting techniques for handling multicast feedback communications according to one or more aspects of this disclosure are shown. Wireless communication system 300 may implement aspects of wireless communication systems 100 and 200, or may be implemented by aspects of these wireless communication systems. For example, wireless communication system 300 includes TX UE115-e, UE 115-f, UE 115-g, and UE 115-h, which may be examples of UE 115 as described herein.

[0066] In some examples, TX UE 115-e can send messages to UEs (e.g., UE 115-f, UE 115-g, and UE 115-h) in multicast (e.g., TX UE sends the same message to the RX UE group). In some cases, TX UE 115-e can receive Phase 1 Sidelink Control Information (SCI) indicating the transport block for the message. In NR V2X, two modes (e.g., or options) are supported for sidelink (SL) HARQ feedback. In mode 1, if the RX UE has not successfully decoded the transport block after decoding the Phase 1 SCI, the RX UE can send a NACK feedback message, and if the RX UE has successfully decoded the transport block after decoding the Phase 1 SCI, the RX UE can suppress (e.g., not send) an ACK feedback message.

[0067] In some cases, Mode 1 SL HARQ feedback can be distance-based. For distance-based HARQ feedback, RX UEs within the configured distance can decode messages sent by TX UE 115-e. An example of distance-based HARQ feedback could be at a traffic junction, where TX UE 115-e sends messages about locations near the traffic junction to RX UEs within the configured distance. For distance-based HARQ feedback, if the relative distance to TX UE 115-e (referred to as the Tx-Rx distance) is less than or equal to the configured communication range 305 indicated in the Phase 2 SCI, the RX UE may attempt to decode the transport block. If the relative distance is greater than the communication range 305, the RX UE may not decode the transport block and may not send a HARQ feedback message. For example, TX UE 115-e may send multicast messages to UE 115-f, UE 115-g, UE 115-h, and UE 115-i. For distance-based HARQ feedback, UE 115-f may have a relative distance greater than the configured communication range 305. UE 115-f may not attempt to decode the message, and UE 115-f may not send a NACK feedback message to TX UE 115-e. UE 115-g, UE 115-h, and UE 115-i may each have a relative distance less than the communication range 305, and UE 115-g, UE 115-h, and UE 115-i may attempt to decode the message. In some cases, UE 115-g and UE 115-h may successfully decode the transport block and avoid sending a NACK feedback message to TX UE 115-e. UE 115-i may fail to decode the transport block and may send a NACK feedback message to TX UE 115-e.

[0068] In Mode 2, if the RX UE has successfully decoded the transport block after decoding the Phase 1 SCI, it can send an ACK feedback message; otherwise, if the RX UE has not successfully decoded the transport block after decoding the Phase 1 SCI, it can send a NACK feedback message. Mode 2 supports NACK and ACK feedback messages from all RX UEs. For example, TX UE 115-e, UE 115-g, UE 115-h, and UE 115-i can be managed multicast. In some cases, TX UE 115-e can send multicast messages to UE 115-g, UE 115-h, and UE 115-i. UE 115-g and UE 115-h can successfully decode the transport block and send an ACK feedback message to TX UE 115-e on their assigned resources. UE 115-i may fail to decode the transport block and may send a NACK feedback message to TX UE 115-e on the assigned resource.

[0069] In Mode 1, the sending RX UEs (e.g., UE 115-g, UE 115-h, and UE 115-i) share the resources used to transmit the corresponding NACK feedback messages. Therefore, TX UE 115-e may not be able to identify which RX UEs are transmitting NACK feedback messages. If TX UE 115-e receives at least one NACK feedback message in Mode 1, TX UE 115-e knows that at least one RX UE (e.g., UE 115-g, UE 115-h, and UE 115-i) within the configured communication range 305 has not correctly decoded the transport block. If TX UE 115-e receives a NACK feedback message corresponding to the multicast message it sent, TX UE 115-e may retransmit the multicast message to all RX UEs (e.g., UE 115-g, UE 115-h, and UE 115-i). In Mode 2, the TX UE 115-e can use the group ID of the RX UE and the assigned resource of the received HARQ feedback message to distinguish the HARQ feedback message of the RX UE. This allows the TX UE to perform a retransmission to the specific RX UE that sent the NACK feedback message.

[0070] When TX UE 115-e operates in Mode 1, if one or more RX UEs (e.g., UE 115-g, UE 115-h, and UE 115-i) are repeatedly transmitting NACK feedback messages, TX UE 115-e may retransmit the multicast message, and TX UE 115-e may not be aware that the NACK feedback message is being repeatedly transmitted by a specific RX UE. In some cases, an RX UE can be the source of repeated NACK feedback messages. For example, due to non-line-of-sight (non-LOS), interference, or a faulty positioning module, one of the RX UEs may incorrectly estimate its location, and in these cases, even if the RX UE is outside the communication range 305, the RX UE may incorrectly estimate its distance to TX UE 115-e as less than the communication range 305 configured by TX UE 115-e. For example, due to the location of the RX UE, the RX UE may fail to correctly decode the transport block and may send a NACK feedback message to TX UE 115-e. In some cases, there may be a malicious RX UE that may intentionally send NACK feedback messages to TX UE115-e to block resources.

[0071] To address potential consecutive NACK feedback and associated retransmissions, TX UE 115-e can handle multicast feedback communication by initiating multicast communication using Mode 1 multicast feedback and dynamically switching to Mode 2 multicast feedback based on whether a retransmission metric meets (e.g., exceeds, reaches, or surpasses) a threshold. In some examples, TX UE 115-e may decide whether to use Mode 1 or Mode 2 feedback. In some cases, TX UE 115-e may use Mode 1 feedback because it may consume fewer resources. For example, TX UE 115-e may send control signaling indicating Mode 1 multicast feedback to RX UEs (e.g., UE 115-g, UE 115-h, and UE 115-i). In some examples, TX UE 115-e may indicate Mode 1 feedback in a Phase 2 SCI.

[0072] When TX UE 115-e uses Mode 1, if a NACK feedback message is present for the transmitted multicast message, TX UE 115-e can retransmit the multicast message at an increased transmission power within the Maximum Transmit Power Level (MTPL). If several or consecutive NACK feedback messages associated with a multicast message are received, TX UE 115-e may retransmit the same data repeatedly, consuming additional resources. In some examples, TX UE 115-e switches to Mode 2 feedback if one or more retransmission metrics meet a threshold number. One or more retransmission metrics may include one or more block error rates of retransmissions or one or more retransmissions. In some examples, an additional consideration may be whether the number of NACK feedback messages is consistent with the number of retransmissions. For example, the number of feedback messages may be equal to the number of retransmissions, or the number of feedback messages may be within a threshold for the number of retransmissions.

[0073] After TX UE 115-e decides to switch to Mode 2 multicast feedback, TX UE 115-e can send control signaling indicating Mode 2 multicast feedback to RX UE. In some examples, TX UE 115-e can indicate Mode 2 feedback in the second-phase SCI. Once multicast feedback switches to Mode 2, TX UE 115-e can use the associated group ID and the allocated resources for the NACK feedback message to estimate whether the NACK feedback message originates from a specific RX UE or whether the NACK feedback message originates from more than one RX UE. For example, TX UE 115-e can determine that a large number of NACK feedback messages originate from a specific RX UE, or that a certain proportion of NACK feedback messages exceeding a threshold originate from a specific RX UE.

[0074] If TX UE 115-e detects a pattern of a specific RX UE transmitting a repeated NACK feedback message, TX UE 115-e may choose to switch back to mode one feedback, ignore the NACK feedback message, remove the specific RX UE from multicast communication, blacklist the identified RX UE, or choose to perform a combination of these techniques. The RX UE transmitting the repeated NACK feedback message may be a malicious UE, a faulty UE, or a UE located at the edge of the configured communication range 305.

[0075] In some examples, after identifying the RX UE that transmits duplicate NACK feedback messages, the TX UE 115-e may broadcast the possible presence of a malicious UE and its details (such as the malicious UE group ID), which may be helpful to other UEs. If the TX UE 115-e is not the group leader, it may notify the group leader of the possible presence of a malicious UE and its details (such as the malicious UE group ID). In some cases, the TX UE 115-e may notify network entity 105-a of the possible presence of a malicious UE and its details (such as the malicious UE group ID). Network entity 105-a may indicate the possible presence of a malicious UE and its details (such as the malicious UE group ID) in a sidelink minimized road test (MDT) report. In some cases, the TX UE 115-e may notify V2X application server 205 of the possible presence of a malicious UE and its details (such as the malicious UE group ID) via application layer messaging. If V2X application server 205 or network entity 105-a receives multiple reports about malicious UEs, V2X application server 205 or network entity 105-a may notify the relevant authorities of the malicious UEs.

[0076] In some cases, a smart malicious UE may not transmit a NACK feedback message when switching to Mode 2 feedback. The TX UE 115-e can detect a smart malicious UE by identifying the absence of NACK feedback messages during Mode 1 feedback and during Mode 2 feedback. If the TX UE 115-e identifies the potential presence of a smart malicious UE, it may ignore the NACK feedback message after switching back to Mode 1 feedback. Additionally, the TX UE 115-e may report the potential presence of a smart malicious UE as described herein. Because NACK feedback messages may exist from other non-malicious RX UEs or genuine RX UEs, the TX UE 115-e may not ignore every NACK feedback message, but it may reduce the maximum retransmission to allow any genuine RX UE to decode and transmit multiple times, which will increase robustness. If TX UE 115-e detects the potential presence of a smart malicious UE, it can report all RX UE IDs that have reported NACK feedback to other UEs, network entity 105-a, and N2X application server 205, indicating that one of the reported UEs is suspected or likely to be a malicious UE. In some examples, TX UE 115-e can increase the transmit power in subsequent retransmissions when identifying a potential smart malicious UE to ensure that the distance-edge RX UE can successfully decode the transport block. After increasing the transmit power, if the NACK feedback message continues in Mode 1, TX UE 115-e can determine the potential presence of a malicious or faulty UE.

[0077] In some examples, the TX UE 115-e can handle multicast feedback communication by initiating multicast communication using mode 1 multicast feedback and dynamically switching to mode 2 multicast feedback based on a retransmission metric meeting a threshold. For example, the TX UE 115-e can use mode 1 feedback to send multicast messages. If the number of retransmissions meets the threshold, the TX UE 115-e can switch to mode 2 feedback and send multicast messages. If the TX UE 115-e identifies that the same RX UE is transmitting NACK feedback messages, it can identify a malicious or faulty UE, switch back to mode 1 feedback, and perform a predetermined number of retransmissions, which may be less than the number of NACK feedback messages received (e.g., per transport block). If TX UE 115-e does not receive a NACK feedback message after switching to Mode 2 feedback, TX UE 115-e may switch to Mode 1 feedback, and TX UE 115-e may retransmit a predetermined number of times, which may be less than the number of NACK feedback messages received. TX UE 115-e may report the presence of any malicious or faulty UE and may switch to Mode 1 feedback.

[0078] Figure 4 Examples of process flow 400 supporting techniques for handling multicast feedback communications according to one or more aspects of this disclosure are shown. In some examples, process flow 400 may be implemented as described in reference respectively. Figure 1 , Figure 2 and Figure 3 The described aspects of the wireless communication systems 100, 200, and 300, or aspects thereof, are implemented. For example, process flow 400 may be implemented by network entity 105-b, which may be as described in reference to [references to other systems]. Figure 1 and Figure 2 An example of the network entity 105 described. For example, process flow 400 may be implemented by a first UE 115-j, a second UE 115-k, and a third UE 115-l, which may be as described in the reference. Figure 1 , Figure 2 and Figure 3 An example of the described UE 115. For example, process flow 400 may be implemented by V2X server 205-a, which may be as described in the reference. Figure 2 The example of the described V2X server 205.

[0079] In some examples, the operations illustrated in process flow 400 may be performed by hardware (e.g., including circuits, processing blocks, logic components, and other components), code (e.g., software executed by a processor), or any combination thereof. Alternative examples are possible, some of which may be performed in a different order than described or not at all. In some cases, steps may include additional features not mentioned below, or additional steps may be added.

[0080] At 405, the first UE 115-j can send a first control signaling indicating a first mode of multicast feedback. The first mode of multicast feedback can be associated with the transmission of NACK feedback and the suppression of ACK feedback. The second UE 115-k and the third UE 115-l can receive the first control signaling indicating the first mode of multicast feedback.

[0081] At 410, the first UE 115-j can send multiple multicast messages, and each of the multiple multicast messages can include a corresponding transport block. The second UE 115-k and the third UE 115-l can receive multiple multicast messages.

[0082] At 415, the first UE 115-j may receive one or more NACK feedback messages associated with one or more multicast messages among a plurality of multicast messages, according to a first mode. Each of the one or more NACK feedback messages may indicate that the reception of at least a portion of the corresponding transport block was unsuccessful. For example, the second UE 115-k may send a NACK feedback message indicating that the reception of at least a portion of the corresponding transport block was unsuccessful, and the third UE 115-l may avoid sending a NACK feedback message indicating that the reception of the corresponding transport block was successful.

[0083] At 420, the first UE 115-j can perform one or more retransmissions of one or more multicast messages among multiple multicast messages based on one or more NACK feedback messages.

[0084] At 425, the first UE 115-j may send a second control signaling indicating a second mode of multicast feedback based on one or more retransmission metrics exceeding a first threshold. The second mode of multicast feedback may be associated with monitoring NACK and ACK feedback. In some examples, the one or more retransmission metrics may include one or more retransmission block error rates, and the first UE 115-j may send the second control signaling based on the block error rate exceeding the first threshold. In some cases, the one or more retransmission metrics may include the number of one or more NACK feedback messages.

[0085] At position 430, the first UE 115-j can send a second multicast message.

[0086] At 435, the first UE 115-j may receive one or more second NACK feedback messages associated with one or more multicast messages among a second plurality of multicast messages from the second UE 115-k, based on the second mode multicast feedback. In some examples, the first UE 115-j may use the associated group ID and the assigned resources associated with the second NACK feedback message to estimate whether the second NACK feedback message originates from a specific RX UE. For example, the first UE 115-k may determine that a large number of second NACK feedback messages originate from the second UE 115-k, or that a certain proportion of the second NACK feedback messages exceed a threshold and originate from the second UE 115-k.

[0087] At 440, the first UE 115-j may send a third control signaling indicating a first mode of multicast feedback. For example, the first UE 115-j may send the third control signaling indicating a first mode of multicast feedback based on the identifier that the second NACK feedback message comes from the second UE 115-k.

[0088] At position 445, the first UE 115-j can send a third multicast message.

[0089] At 450, the first UE 115-j can receive one or more third NACK feedback messages associated with one or more multicast messages in a third plurality of multicast messages, according to a first mode.

[0090] At 455, the first UE 115-j may suppress one or more retransmissions of one or more multicast messages among the third plurality of multicast messages based on one or more third NACK feedback messages. In some examples, UE 115-j may perform a fixed number of retransmissions of one or more multicast messages among the third plurality of multicast messages based on one or more third NACK feedback messages. For example, the first UE 115-j may suppress one or more retransmissions of one or more multicast messages among the third plurality of multicast messages based on an identifier that a second NACK feedback message comes from a second UE 115-k.

[0091] At 460, the first UE 115-j may send a signaling instruction to network entity 105-b, V2X server 205-a, or third UE 115-l, or any combination thereof, instructing the removal of the second UE 115-k from multicast communications. In some examples, UE 115-j may send a signaling instruction to network entity 105-b, V2X server 205-a, third UE 115-l, or any combination thereof, instructing the second UE 115-k to have violated the restrictions associated with the NACK feedback message.

[0092] Figure 5A block diagram 500 illustrates a device 505 supporting techniques for handling multicast feedback communications according to one or more aspects of this disclosure. Device 505 may be an example of various aspects of a UE 115 as described herein. Device 505 may include a receiver 510, a transmitter 515, and a communication manager 520. Device 505, or one or more components of device 505 (e.g., receiver 510, transmitter 515, and communication manager 520), may include at least one processor that may be coupled to at least one memory to individually or jointly support or implement the described techniques. Each of these components may communicate with each other (e.g., via one or more buses).

[0093] Receiver 510 may provide components for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels associated with technologies used for handling multicast feedback communications). The information may be passed to other components of device 505. Receiver 510 may utilize a single antenna or a collection of antennas.

[0094] Transmitter 515 may provide components for transmitting signals generated by other components of device 505. For example, transmitter 515 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels associated with techniques used for handling multicast feedback communications). In some examples, transmitter 515 may be co-located with receiver 510 in a transceiver module. Transmitter 515 may utilize a single antenna or a collection of multiple antennas.

[0095] The communication manager 520, receiver 510, transmitter 515, or various combinations thereof, or various components thereof, may be examples of components for performing various aspects of the techniques for handling multicast feedback communications as described herein. For example, the communication manager 520, receiver 510, transmitter 515, or various combinations thereof, or components thereof, may be able to perform one or more of the functions described herein.

[0096] In some examples, the communication manager 520, receiver 510, transmitter 515, or various combinations or components thereof may be implemented in hardware (e.g., in communication management circuitry). The hardware may include at least one of the following: a processor, digital signal processor (DSP), central processing unit (CPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, microcontroller, discrete gate or transistor logic component, discrete hardware component, or any combination thereof, configured as or otherwise individually or collectively to support components for performing the functions described herein. In some examples, at least one processor and at least one memory coupled to said at least one processor may be configured to perform one or more of the functions described herein (e.g., instructions stored in at least one memory are executed individually or collectively by one or more processors).

[0097] Additionally or alternatively, the communication manager 520, receiver 510, transmitter 515, or various combinations or components thereof may be implemented in code (e.g., as communication management software or firmware) executed by at least one processor. If implemented in code executed by at least one processor, the functionality of the communication manager 520, receiver 510, transmitter 515, or various combinations or components thereof may be performed by (e.g., a general-purpose processor, DSP, CPU, ASIC, FPGA, microcontroller, or any combination of these or other programmable logic devices configured, either individually or collectively, as components for performing the functions described in this disclosure).

[0098] In some examples, the communication manager 520 may be configured to use a receiver 510, a transmitter 515, or both, or otherwise cooperate with them to perform various operations (e.g., receiving, acquiring, monitoring, outputting, transmitting). For example, the communication manager 520 may receive information from the receiver 510, transmit information to the transmitter 515, or integrate with the receiver 510, the transmitter 515, or both to acquire information, output information, or perform various other operations as described herein.

[0099] According to the examples disclosed herein, the communication manager 520 may support wireless communication. For example, the communication manager 520 is capable of, configured to, or operable to support components for transmitting first control signaling indicative of a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback. The communication manager 520 is capable of, configured to, or operable to support components for transmitting a set of multiple multicast messages, each multicast message in the set including a corresponding transport block. The communication manager 520 is capable of, configured to, or operable to support components for receiving one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages according to the first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of the corresponding transport block was unsuccessful. The communication manager 520 is capable of, configured to, or operable to support components for performing one or more retransmissions of one or more multicast messages in the set of multiple multicast messages based on one or more NACK feedback messages. The communication manager 520 is capable of, configured to, or operable to support components for sending a second control signaling for a second mode indicating multicast feedback based on one or more retransmission metrics exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0100] By including or configuring a communication manager 520 according to an example as described herein, device 505 (e.g., controlling receiver 510, transmitter 515, communication manager 520 or a combination thereof or at least one processor otherwise coupled to them) can support techniques for more efficient use of communication resources.

[0101] Figure 6 A block diagram 600 illustrates a device 605 supporting techniques for handling multicast feedback communications according to one or more aspects of this disclosure. Device 605 may be an example of aspects of device 505 or UE 115 as described herein. Device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. Device 605, or one or more components of device 605 (e.g., receiver 610, transmitter 615, and communication manager 620), may include at least one processor that may be coupled to at least one memory to support the described techniques. Each of these components may communicate with each other (e.g., via one or more buses).

[0102] Receiver 610 may provide components for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels associated with technologies used for handling multicast feedback communications). The information may be passed to other components of device 605. Receiver 610 may utilize a single antenna or a collection of antennas.

[0103] Transmitter 615 may provide components for transmitting signals generated by other components of device 605. For example, transmitter 615 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels associated with techniques used for handling multicast feedback communications). In some examples, transmitter 615 may be co-located with receiver 610 in a transceiver module. Transmitter 615 may utilize a single antenna or a collection of multiple antennas.

[0104] Device 605 or its various components may be examples of parts for performing various aspects of the techniques described herein for handling multicast feedback communications. For example, communication manager 620 may include a first mode manager 625, a multicast message manager 630, a feedback manager 635, a retransmission message manager 640, a second mode manager 645, or any combination thereof. Communication manager 620 may be examples of aspects of communication manager 520 as described herein. In some examples, communication manager 620 or its various components may be configured to use receiver 610, transmitter 615, or both, or otherwise cooperate with them to perform various operations (e.g., receiving, acquiring, monitoring, outputting, transmitting). For example, communication manager 620 may receive information from receiver 610, transmit information to transmitter 615, or be integrated in combination with receiver 610, transmitter 615, or both to acquire information, output information, or perform various other operations as described herein.

[0105] According to the examples disclosed herein, the communication manager 620 may support wireless communication. The first mode manager 625 is capable of, configured to, or operable to support components for transmitting a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback. The multicast message manager 630 is capable of, configured to, or operable to support components for transmitting a set of multiple multicast messages, each multicast message in the set including a corresponding transport block. The feedback manager 635 is capable of, configured to, or operable to support components for receiving one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages according to a first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of a corresponding transport block was unsuccessful. The retransmission message manager 640 is capable of, configured to, or operable to support components for performing one or more retransmissions of one or more multicast messages in the set of multiple multicast messages based on one or more NACK feedback messages. The second mode manager 645 is capable of, configured to, or operable to support components for sending a second control signaling indicating a second mode of multicast feedback based on one or more retransmission metrics exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0106] Figure 7 A block diagram 700 illustrates a communication manager 720 supporting techniques for handling multicast feedback communications according to one or more aspects of this disclosure. The communication manager 720 may be an example of aspects of the communication manager 520, communication manager 620, or both as described herein. The communication manager 720 or its various components may be examples of parts for performing various aspects of the techniques for handling multicast feedback communications as described herein. For example, the communication manager 720 may include a first mode manager 725, a multicast message manager 730, a feedback manager 735, a retransmission message manager 740, a second mode manager 745, a removal manager 750, or any combination thereof. Each of these components, or its components or sub-components (e.g., one or more processors, one or more memories), may communicate directly or indirectly with each other (e.g., via one or more buses).

[0107] According to the examples disclosed herein, the communication manager 720 may support wireless communication. The first mode manager 725 is capable of, configured to, or operable to support components for transmitting a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback. The multicast message manager 730 is capable of, configured to, or operable to support components for transmitting a set of multiple multicast messages, each multicast message in the set including a corresponding transport block. The feedback manager 735 is capable of, configured to, or operable to support components for receiving one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages according to a first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of a corresponding transport block was unsuccessful. The retransmission message manager 740 is capable of, configured to, or operable to support components for performing one or more retransmissions of one or more multicast messages in the set of multiple multicast messages based on one or more NACK feedback messages. The second mode manager 745 is capable of, configured to, or operable to support components for sending a second control signaling indicating a second mode of multicast feedback based on one or more retransmission metrics exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0108] In some examples, in order to support the transmission of second control signaling, the second mode manager 745 is capable of, can be configured to, or is operable to support components for transmitting second control signaling based on a block error rate exceeding a first threshold.

[0109] In some examples, the metric for one or more retransmissions includes the number of one or more NACK feedback messages.

[0110] In some examples, the multicast message manager 730 is capable of, configured to, or operable to support components for sending a second set of multiple multicast messages. In some examples, the feedback manager 735 is capable of, configured to, or operable to support components for receiving, from a second UE, one or more second NACK feedback messages associated with one or more multicast messages in the second set of multiple multicast messages, according to a second mode. In some examples, the first mode manager 725 is capable of, configured to, or operable to support components for sending third control signaling indicating a first mode of multicast feedback.

[0111] In some examples, the multicast message manager 730 is capable of, configured to, or operable to support components for sending a third set of multiple multicast messages. In some examples, the feedback manager 735 is capable of, configured to, or operable to support components for receiving one or more third NACK feedback messages associated with one or more multicast messages in the third set of multiple multicast messages, according to a first mode. In some examples, the retransmission message manager 740 is capable of, configured to, or operable to support components for suppressing one or more retransmissions of one or more multicast messages in the third set of multiple multicast messages based on one or more third NACK feedback messages.

[0112] In some examples, the multicast message manager 730 is capable of, configured to, or operable to support components for sending a third set of multiple multicast messages. In some examples, the feedback manager 735 is capable of, configured to, or operable to support components for receiving one or more third NACK feedback messages associated with one or more multicast messages in the third set of multiple multicast messages, according to a first mode. In some examples, the retransmission message manager 740 is capable of, configured to, or operable to support components for performing a fixed number of retransmissions of one or more multicast messages in the third set of multiple multicast messages based on one or more third NACK feedback messages.

[0113] In some examples, the removal manager 750 is capable of, configured to, or able to operate to support components for sending signaling instructions to remove a second UE from multicast communications to a third UE, a network entity, a vehicle networking application server, or any combination thereof.

[0114] In some examples, the removal manager 750 is capable of, configured to, or able to operate to support components for sending signaling to a third UE, a network entity, a vehicle networking application server, or any combination thereof, indicating that a second UE has violated the restrictions associated with the NACK feedback message.

[0115] Figure 8A diagram of a system 800 including a device 805 supporting techniques for handling multicast feedback communications, according to one or more aspects of this disclosure, is shown. Device 805 may be an example of device 505, device 605, or UE 115 as described herein, or may include components thereof. Device 805 may communicate with one or more network entities 105, one or more UEs 115, or any combination thereof (e.g., wirelessly). Device 805 may include components for bidirectional voice and data communications, including components for transmitting and receiving communications, such as a communication manager 820, an input / output (I / O) controller 810, a transceiver 815, an antenna 825, at least one memory 830, code 835, and at least one processor 840. These components may communicate electronically or be coupled in other ways (e.g., operational ground, communication ground, functional ground, electronic ground, electrical ground) via one or more buses (e.g., bus 845).

[0116] I / O controller 810 manages the input and output signals of device 805. I / O controller 810 can also manage peripheral devices not integrated into device 805. In some cases, I / O controller 810 may represent a physical connection or port to an external peripheral device. In some cases, I / O controller 810 may utilize an operating system such as iOS. ® ANDROID ® MS-DOS ® MS-WINDOWS ® OS / 2 ® UNIX ® LINUX ® Or another known operating system. Additionally or alternatively, the I / O controller 810 may represent or interact with a modem, keyboard, mouse, touchscreen, or similar device. In some cases, the I / O controller 810 may be implemented as part of one or more processors, such as at least one processor 840. In some cases, a user may interact with the device 805 via the I / O controller 810 or via hardware components controlled by the I / O controller 810.

[0117] In some cases, device 805 may include a single antenna 825. However, in other cases, device 805 may have more than one antenna 825, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. Transceiver 815 may communicate bidirectionally via one or more antennas 825, a wired link, or a wireless link as described herein. For example, transceiver 815 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. Transceiver 815 may also include a modem for: modulating packets; providing the modulated packets to one or more antennas 825 for transmission; and demodulating packets received from one or more antennas 825. Transceiver 815, or transceiver 815 and one or more antennas 825, may be an example of transmitter 515, transmitter 615, receiver 510, receiver 610, or any combination thereof or components thereof as described herein.

[0118] At least one memory 830 may include random access memory (RAM) and read-only memory (ROM). At least one memory 830 may store computer-readable, computer-executable code 835, including instructions that, when executed by at least one processor 840, cause device 805 to perform the various functions described herein. Code 835 may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, code 835 may not be directly executable by at least one processor 840, but may enable a computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, at least one memory 830 may contain a basic I / O system (BIOS), etc., which controls basic hardware or software operations, such as interaction with peripheral components or devices.

[0119] At least one processor 840 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, at least one processor 840 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into at least one processor 840. At least one processor 840 may be configured to execute computer-readable instructions stored in memory (e.g., at least one memory 830) to cause device 805 to perform various functions (e.g., functions or tasks supporting techniques for handling multicast feedback communications). For example, device 805 or components of device 805 may include at least one processor 840 and at least one memory 830 coupled to or coupled to at least one processor 840, wherein at least one processor 840 and at least one memory 830 are configured to perform the various functions described herein. In some examples, at least one processor 840 may include multiple processors, and at least one memory 830 may include multiple memories. One or more of a plurality of processors may be coupled to one or more of a plurality of memories, which may be configured individually or collectively to perform the various functions described herein. In some examples, at least one processor 840 may be a component of a processing system, which may refer to a system of machines (such as a series of machines), circuitry (including, for example, one or both of processor circuitry (which may include at least one processor 840) and memory circuitry (which may include at least one memory 830)) or components that receive or receive input and process the input to produce, generate or obtain a set of outputs. The processing system may be configured to perform one or more of the functions described herein. Thus, at least one processor 840 or a processing system including at least one processor 840 may be configured, capable of being configured, or operable to cause device 805 to perform one or more of the functions described herein. Furthermore, as described herein, “configured to,” “capable of being configured,” and “operable to” are used interchangeably and may be associated with the ability to perform one or more of the functions described herein when executing code stored in at least one memory 830 or otherwise.

[0120] According to the examples disclosed herein, the communication manager 820 may support wireless communication. For example, the communication manager 820 may be capable of, configured to, or operable to support components for transmitting first control signaling indicative of a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback. The communication manager 820 may be capable of, configured to, or operable to support components for transmitting a set of multiple multicast messages, each multicast message in the set including a corresponding transport block. The communication manager 820 may be capable of, configured to, or operable to support components for receiving one or more NACK feedback messages associated with one or more multicast messages in the set of multiple multicast messages according to the first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of the corresponding transport block was unsuccessful. The communication manager 820 may be capable of, configured to, or operable to support components for performing one or more retransmissions of one or more multicast messages in the set of multiple multicast messages based on one or more NACK feedback messages. The communication manager 820 is capable of, configured to, or able to operate to support components for sending a second control signaling for a second mode indicating multicast feedback based on one or more retransmission metrics exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

[0121] By including or configuring a communication manager 820 according to an example as described herein, device 805 can support techniques for improving communication reliability, reducing latency, utilizing communication resources more efficiently, and improving coordination between devices.

[0122] In some examples, the communication manager 820 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using a transceiver 815, one or more antennas 825, or any combination thereof, or otherwise cooperating with them. Although the communication manager 820 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 820 may be supported or executed by at least one processor 840, at least one memory 830, code 835, or any combination thereof. For example, code 835 may include instructions that can be executed by at least one processor 840 to cause device 805 to perform various aspects of the techniques described herein for handling multicast feedback communications, or at least one processor 840 and at least one memory 830 may be otherwise configured to perform or support such operations individually or jointly.

[0123] Figure 9A flowchart illustrating a method 900 for handling multicast feedback communications, exemplifying various aspects of this disclosure, is shown. Operation of method 900 may be implemented by a UE or its components as described herein. For example, operation of method 900 may be performed by, as referenced... Figures 1 to 8 The UE 115 described herein is used to perform this function. In some examples, the UE can execute a set of instructions to control the functional elements of the UE to perform the described function. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described function.

[0124] At 905, the method may include sending first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback. Operation of block 905 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 905 may be provided by reference to [reference needed]. Figure 7 The first mode manager 725 is described and executed.

[0125] At 910, the method may include sending a set of multiple multicast messages, each multicast message in the set including a corresponding transport block. The operation of block 910 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 910 may be derived from references... Figure 7 The multicast message manager 730 described is used to execute this.

[0126] At 915, the method may include receiving one or more NACK feedback messages associated with one or more multicast messages in a set of multiple multicast messages according to a first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of a corresponding transport block was unsuccessful. Operation of block 915 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 915 may be provided by reference to [reference needed]. Figure 7 The feedback manager 735 described is used to execute this.

[0127] At 920, the method may include performing one or more retransmissions of one or more multicast messages from a set of multiple multicast messages based on one or more NACK feedback messages. The operation of box 920 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 920 may be derived from references... Figure 7 The resend message manager 740 described is used to perform this.

[0128] At 925, the method may include sending a second control signaling indicating a second mode of multicast feedback based on one or more retransmission metrics exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback. Operation of block 925 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 925 may be provided by reference to [reference needed]. Figure 7 The second mode manager 745 is described and executed.

[0129] Figure 10 A flowchart illustrating a method 1000 for handling multicast feedback communications, illustrative of various aspects of this disclosure, is shown. Operation of method 1000 may be implemented by a UE or its components as described herein. For example, operation of method 1000 may be implemented by, as referenced... Figures 1 to 8 The UE 115 described herein is used to perform this function. In some examples, the UE can execute a set of instructions to control the functional elements of the UE to perform the described function. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described function.

[0130] At 1005, the method may include sending first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback. The operation of block 1005 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1005 may be provided by reference to [reference needed]. Figure 7 The first mode manager 725 is described and executed.

[0131] At 1010, the method may include sending a set of multiple multicast messages, each multicast message in the set including a corresponding transport block. The operation of block 1010 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1010 may be derived from references... Figure 7 The multicast message manager 730 described is used to execute this.

[0132] At 1015, the method may include receiving one or more NACK feedback messages associated with one or more multicast messages in a set of multiple multicast messages according to a first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of a corresponding transport block was unsuccessful. The operation of block 1015 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1015 may be provided by reference to [reference]. Figure 7 The feedback manager 735 described is used to execute this.

[0133] At 1020, the method may include performing one or more retransmissions of one or more multicast messages from a set of multiple multicast messages based on one or more NACK feedback messages. The operation of block 1020 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1020 may be derived from references... Figure 7 The resend message manager 740 described is used to perform this.

[0134] At 1025, the method may include sending a second control signaling indicating a second mode of multicast feedback based on one or more retransmission metrics exceeding a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback. Operation of block 1025 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1025 may be provided by reference to [reference needed]. Figure 7 The second mode manager 745 is described and executed.

[0135] At 1030, the method may include sending a second set of multiple multicast messages. The operation of box 1030 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1030 may be derived from references... Figure 7 The multicast message manager 730 described is used to execute this.

[0136] At 1035, the method may include receiving, according to a second mode, one or more second NACK feedback messages associated with one or more multicast messages from a second set of multiple multicast messages. Operation of block 1035 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1035 may be provided by reference to... Figure 7 The feedback manager 735 described is used to execute this.

[0137] The following provides an overview of the various aspects of this disclosure:

[0138] Aspect 1: A method for wireless communication by a first UE, the method comprising: transmitting a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of NACK feedback and the suppression of ACK feedback; transmitting a plurality of multicast messages, each of the plurality of multicast messages including a corresponding transport block; receiving one or more NACK feedback messages associated with one or more of the plurality of multicast messages according to the first mode, wherein each of the one or more NACK feedback messages indicates that reception of at least a portion of the corresponding transport block was unsuccessful; performing one or more retransmissions of the one or more multicast messages based on the one or more NACK feedback messages; and transmitting a second control signaling indicating a second mode of multicast feedback based on a metric of the one or more retransmissions exceeding a first threshold, wherein the second mode is associated with monitoring NACK feedback and ACK feedback.

[0139] Aspect 2: According to the method of aspect 1, wherein the metric of the one or more retransmissions includes the block error rate of the one or more retransmissions, and wherein sending the second control signaling further includes: sending the second control signaling at least in part based on the block error rate exceeding the first threshold.

[0140] Aspect 3: According to the method of aspect 1, the metric of the one or more retransmissions includes the number of the one or more NACK feedback messages.

[0141] Aspect 4: The method according to any one of Aspects 1 to 3, the method further comprising: sending a second plurality of multicast messages; receiving from a second UE one or more second NACK feedback messages associated with one or more of the second plurality of multicast messages according to a second mode; and sending a third control signaling indicating the first mode of multicast feedback.

[0142] Aspect 5: The method according to aspect 4, the method further comprising: sending a third plurality of multicast messages; receiving one or more third NACK feedback messages associated with one or more multicast messages in the third plurality of multicast messages according to the first mode; and suppressing one or more retransmissions of the one or more multicast messages in the third plurality of multicast messages based on the one or more third NACK feedback messages.

[0143] Aspect 6: The method according to aspect 4, the method further comprising: sending a third plurality of multicast messages; receiving one or more third NACK feedback messages associated with one or more multicast messages in the third plurality of multicast messages according to the first mode; and performing a fixed number of retransmissions of the one or more multicast messages in the third plurality of multicast messages based on the one or more third NACK feedback messages.

[0144] Aspect 7: The method according to any one of Aspects 4 to 6, the method further comprising: sending a signaling instruction to remove the second UE from multicast communications to a third UE, to a network entity, to a vehicle networking application server, or any combination thereof.

[0145] Aspect 8: The method according to any one of Aspects 4 to 7, the method further comprising: sending a signaling to a third UE, to a network entity, to a vehicle networking application server, or any combination thereof, indicating that the second UE has violated the restriction associated with the NACK feedback message.

[0146] Aspect 9: A first UE for wireless communication, the first UE comprising: one or more memories storing processor-executable code; and one or more processors coupled to the one or more memories and capable of operating individually or jointly to execute the code to cause the first UE to perform a method according to any one of Aspects 1 to 8.

[0147] Aspect 10: A first UE for wireless communication, the first UE comprising at least one component for performing the method according to any one of aspects 1 to 8.

[0148] Aspect 11: A non-transitory computer-readable medium storing code for wireless communication, said code including instructions executable by a processor to perform a method according to any one of aspects 1 to 8.

[0149] It should be noted that the methods described herein describe possible specific implementations, and the operations and steps can be rearranged or otherwise modified, and other specific implementations are also possible. Furthermore, aspects from two or more of these methods can be combined.

[0150] While aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for illustrative purposes, and the terms LTE, LTE-A, LTE-A Pro, or NR may be used in most of the description, the techniques described herein are also applicable to networks outside of LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described are applicable to a variety of other wireless communication systems, such as Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0151] The information and signals described herein can be represented using any of a variety of different techniques and skills. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof.

[0152] The various exemplary blocks and components described herein can be implemented or performed using a general-purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic unit, discrete hardware component, or any combination thereof, designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in alternative embodiments, a processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration). Any function or operation described herein that can be performed by a processor may be performed by multiple processors capable of performing the described functions or operations individually or jointly.

[0153] The functions described herein can be implemented using hardware, software executed by a processor, firmware, or any combination thereof. When implemented using software executed by a processor, the functions can be stored as one or more instructions or code on a computer-readable medium or transmitted using one or more instructions or code on a computer-readable medium. Other examples and specific implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these. Features implementing the functions can also be physically located in various locations, including portions distributed such that the functions are implemented in different physical locations.

[0154] Computer-readable media includes both non-transitory computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. Non-transitory storage media can be any available medium accessible 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, compressed optical disc (CD) ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code components in the form of instructions or data structures, and accessible by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Furthermore, any connection is appropriately referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of computer-readable media. As used herein, disks and optical discs include CDs, laser discs, optical discs, digital multifunction discs (DVDs), floppy disks, and Blu-ray discs. Disks can magnetically reproduce data, and optical discs can optically reproduce data using lasers. Combinations of the above are also included within the scope of computer-readable media. Any function or operation described herein that can be performed by memory can be performed by multiple memories capable of performing the described function or operation individually or jointly.

[0155] As used herein, the word "or" in a list of items (e.g., a list of items accompanied by phrases such as "at least one of" or "one or more of") in the claims indicates an inclusive list, such that a list of at least one of, for example, 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). Furthermore, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, an example step described as "based on condition A" could be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "at least partially based on".

[0156] As used herein, including in claims, the article “a” preceding a noun is open-ended and is understood to refer to “at least one” or “one or more” of those nouns. Therefore, the terms “a,” “at least one,” “one or more,” and “at least one of one or more” are interchangeable. For example, where a claim enumerates “components” performing one or more functions, each of the individual functions may be performed by a single component or by any combination of multiple components. Thus, the term “component” having a characteristic or performing a function may refer to “at least one of one or more components” having a particular characteristic or performing a particular function. Subsequent references to a component introduced with the article “a” using the terms “the” or “the” can refer to any or all of the one or more components. For example, a component introduced with the article “a” can be understood to mean “one or more components,” and subsequent reference to “the component” in a claim can be understood as equivalent to referring to “at least one of the one or more components.” Similarly, subsequent references to a component introduced with the terms “the” or “the” as “one or more components” can refer to any or all of the one or more components. For example, reference to "the one or more components" in the subsequent claims can be understood as equivalent to reference to "at least one of the one or more components".

[0157] The term "determine" encompasses a variety of actions, and therefore, "determine" can include calculation, computation, processing, derivation, investigation, lookup (such as by searching in a table, database, or other data structure), identification, and similar actions. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data stored in memory), etc. Moreover, "determine" can include parsing, acquiring, selecting, choosing, creating, and other similar actions.

[0158] In the accompanying drawings, similar components or features may have the same reference numerals. Furthermore, various components of the same type can be distinguished by adding a dash after the reference numerals and a second reference numeral for differentiation between similar components. If only the first reference numeral is used in the specification, the description can be applied to any component among similar components having the same first reference numeral, regardless of the second or other subsequent reference numerals.

[0159] The description herein, illustrated with reference to the accompanying drawings, describes an example configuration and does not represent all achievable examples or those within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration," not "preferred" or "advantageous over other examples." The detailed description includes specific details used to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concept of the described examples.

[0160] The description herein is provided to enable those skilled in the art to implement or use this disclosure. Various modifications to this disclosure will be 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 this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A first user equipment (UE), the first user equipment (UE) comprising: One or more memories, wherein the one or more memories store processor-executable code; and One or more processors, said one or more processors coupled to said one or more memories and capable of operating individually or jointly to execute said code to enable the first UE: Send a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of negative acknowledgment (NACK) feedback and the suppression of acknowledgment (ACK) feedback; Send multiple multicast messages, each of which includes a corresponding transport block; According to the first mode, one or more NACK feedback messages associated with one or more multicast messages among the plurality of multicast messages are received, wherein each of the one or more NACK feedback messages indicates that at least a portion of the corresponding transport block was not successfully received; Based on the one or more NACK feedback messages, perform one or more retransmissions of the one or more multicast messages among the plurality of multicast messages; as well as Based on the fact that one or more retransmission metrics exceed a first threshold, a second control signaling indicating a second mode of multicast feedback is sent, wherein the second mode is associated with monitoring NACK and ACK feedback.

2. The first UE according to claim 1, wherein, In order to send the second control signaling, the one or more processors can also operate individually or jointly to execute the code to cause the first UE to: The second control signaling is sent at least in part based on the block error rate exceeding the first threshold.

3. The first UE according to claim 1, wherein the metric for the one or more retransmissions includes the number of the one or more NACK feedback messages.

4. The first UE according to claim 1, wherein the one or more processors are further capable of operating individually or jointly to execute the code to cause the first UE to: Send a second or more multicast messages; According to the second mode, the second UE receives one or more second NACK feedback messages associated with one or more multicast messages in the second plurality of multicast messages; as well as Send a third control signaling for the first mode that indicates multicast feedback.

5. The first UE according to claim 4, wherein the one or more processors are further capable of operating individually or jointly to execute the code to cause the first UE to: Send a third or more multicast messages; According to the first mode, receive one or more third NACK feedback messages associated with one or more multicast messages in the third plurality of multicast messages; as well as Based on the one or more third NACK feedback messages, suppress one or more retransmissions of the one or more multicast messages in the third plurality of multicast messages.

6. The first UE according to claim 4, wherein the one or more processors are further capable of operating individually or jointly to execute the code to cause the first UE to: Send a third or more multicast messages; According to the first mode, receive one or more third NACK feedback messages associated with one or more multicast messages in the third plurality of multicast messages; as well as A fixed number of retransmissions of the one or more multicast messages in the third plurality of multicast messages are performed based on the one or more third NACK feedback messages.

7. The first UE according to claim 4, wherein the one or more processors are further capable of operating individually or jointly to execute the code to cause the first UE to: Send a signaling instruction to remove the second UE from multicast communications to a third UE, a network entity, a vehicle networking application server, or any combination thereof.

8. The first UE according to claim 4, wherein the one or more processors are further capable of operating individually or jointly to execute the code to cause the first UE to: Send a signaling message to a third UE, to a network entity, to a vehicle networking application server, or any combination thereof, indicating that the second UE has violated the restrictions associated with the NACK feedback message.

9. A method for wireless communication by a first user equipment (UE), the method comprising: Send a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of negative acknowledgment (NACK) feedback and the suppression of acknowledgment (ACK) feedback; Send multiple multicast messages, each of which includes a corresponding transport block; According to the first mode, one or more NACK feedback messages associated with one or more multicast messages among the plurality of multicast messages are received, wherein each of the one or more NACK feedback messages indicates that at least a portion of the corresponding transport block was not successfully received; Based on the one or more NACK feedback messages, perform one or more retransmissions of the one or more multicast messages among the plurality of multicast messages; as well as Based on the fact that one or more retransmission metrics exceed a first threshold, a second control signaling indicating a second mode of multicast feedback is sent, wherein the second mode is associated with monitoring NACK and ACK feedback.

10. The method of claim 9, wherein the metric for the one or more retransmissions includes the block error rate of the one or more retransmissions, and wherein sending the second control signaling further includes: The second control signaling is sent at least in part based on the block error rate exceeding the first threshold.

11. The method of claim 9, wherein the metric for the one or more retransmissions includes the number of the one or more NACK feedback messages.

12. The method according to claim 9, further comprising: Send a second or more multicast messages; According to the second mode, the second UE receives one or more second NACK feedback messages associated with one or more multicast messages in the second plurality of multicast messages; as well as Send a third control signaling for the first mode that indicates multicast feedback.

13. The method according to claim 12, further comprising: Send a third or more multicast messages; According to the first mode, receive one or more third NACK feedback messages associated with one or more multicast messages in the third plurality of multicast messages; as well as Based on the one or more third NACK feedback messages, suppress one or more retransmissions of the one or more multicast messages in the third plurality of multicast messages.

14. The method according to claim 12, further comprising: Send a third or more multicast messages; According to the first mode, receive one or more third NACK feedback messages associated with one or more multicast messages in the third plurality of multicast messages; as well as A fixed number of retransmissions of the one or more multicast messages in the third plurality of multicast messages are performed based on the one or more third NACK feedback messages.

15. The method according to claim 12, further comprising: Send a signaling instruction to remove the second UE from multicast communications to a third UE, a network entity, a vehicle networking application server, or any combination thereof.

16. The method according to claim 12, further comprising: Send a signaling message to a third UE, to a network entity, to a vehicle networking application server, or any combination thereof, indicating that the second UE has violated the restrictions associated with the NACK feedback message.

17. A first user equipment (UE) for wireless communication, the first user equipment (UE) comprising: A component for sending a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of negative acknowledgment (NACK) feedback and the suppression of acknowledgment (ACK) feedback; A component for sending multiple multicast messages, each of which includes a corresponding transport block; A component for receiving one or more NACK feedback messages associated with one or more multicast messages among the plurality of multicast messages according to the first mode, wherein each of the one or more NACK feedback messages indicates that at least a portion of the corresponding transport block was not successfully received; Components for performing one or more retransmissions of one or more multicast messages among the plurality of multicast messages based on the one or more NACK feedback messages; and A component for sending a second control signaling indicating a second mode of multicast feedback based on a metric that the one or more retransmissions exceed a first threshold, wherein the second mode is associated with monitoring NACK and ACK feedback.

18. The first UE of claim 17, wherein the component for transmitting the second control signaling further comprises: A component for sending the second control signaling based at least in part on a block error rate exceeding the first threshold.

19. The first UE of claim 17, wherein the metric for the one or more retransmissions includes the number of the one or more NACK feedback messages.

20. The first UE according to claim 17, further comprising: Components used to send a second or more multicast messages; A component for receiving, according to the second mode, one or more second NACK feedback messages associated with one or more multicast messages among the second plurality of multicast messages from a second UE; and A component for sending third control signaling for the first mode indicating multicast feedback.

21. The first UE according to claim 20, further comprising: Components used to send third or more multicast messages; A component for receiving one or more third NACK feedback messages associated with one or more multicast messages among the third plurality of multicast messages, according to the first mode; and A component for suppressing one or more retransmissions of one or more multicast messages in the third plurality of multicast messages based on the one or more third NACK feedback messages.

22. The first UE according to claim 20, further comprising: Components used to send third or more multicast messages; A component for receiving one or more third NACK feedback messages associated with one or more multicast messages among the third plurality of multicast messages, according to the first mode; and A component for performing a fixed number of retransmissions of the one or more multicast messages in the third plurality of multicast messages based on the one or more third NACK feedback messages.

23. The first UE according to claim 20, further comprising: A component for sending signaling instructions to remove the second UE from multicast communications to a third UE, a network entity, a vehicle networking application server, or any combination thereof.

24. A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by one or more processors to: Send a first control signaling indicating a first mode of multicast feedback, wherein the first mode is associated with the transmission of negative acknowledgment (NACK) feedback and the suppression of acknowledgment (ACK) feedback; Send multiple multicast messages, each of which includes a corresponding transport block; According to the first mode, one or more NACK feedback messages associated with one or more multicast messages among the plurality of multicast messages are received, wherein each of the one or more NACK feedback messages indicates that at least a portion of the corresponding transport block was not successfully received; Based on the one or more NACK feedback messages, perform one or more retransmissions of the one or more multicast messages among the plurality of multicast messages; as well as Based on the fact that one or more retransmission metrics exceed a first threshold, a second control signaling indicating a second mode of multicast feedback is sent, wherein the second mode is associated with monitoring NACK and ACK feedback.

25. The non-transitory computer-readable medium of claim 24, wherein the instructions for transmitting the second control signaling are further executable by the one or more processors to: The second control signaling is sent at least in part based on the block error rate exceeding the first threshold.

26. The non-transitory computer-readable medium of claim 24, wherein the measure of retransmission of the one or more retransmissions includes the number of the one or more NACK feedback messages.

27. The non-transitory computer-readable medium of claim 24, wherein the instructions are further executable by the one or more processors to: Send a second or more multicast messages; According to the second mode, the second UE receives one or more second NACK feedback messages associated with one or more multicast messages among the second plurality of multicast messages; and Send a third control signaling for the first mode that indicates multicast feedback.

28. The non-transitory computer-readable medium of claim 27, wherein the instructions are further executable by the one or more processors to: Send a third or more multicast messages; According to the first mode, receive one or more third NACK feedback messages associated with one or more multicast messages among the third plurality of multicast messages; and Based on the one or more third NACK feedback messages, suppress one or more retransmissions of the one or more multicast messages in the third plurality of multicast messages.

29. The non-transitory computer-readable medium of claim 27, wherein the instructions are further executable by the one or more processors to: Send a third or more multicast messages; According to the first mode, receive one or more third NACK feedback messages associated with one or more multicast messages among the third plurality of multicast messages; and A fixed number of retransmissions of the one or more multicast messages in the third plurality of multicast messages are performed based on the one or more third NACK feedback messages.

30. The non-transitory computer-readable medium of claim 27, wherein the instructions are further executable by the one or more processors to: Send a signaling message to a third UE, to a network entity, to a vehicle networking application server, or any combination thereof, indicating that the second UE has violated the restrictions associated with the NACK feedback message.

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