Patent Description:
The following abbreviations are herewith defined, at least some of which are referred to within the following description: Third Generation Partnership Project ("3GPP"), <NUM>th Generation ("<NUM>"), <NUM>th Generation ("<NUM>"), <NUM> System ("5GS"), Positive-Acknowledgment ("ACK"), Aggregation Level ("AL"), Access and Mobility Management Function ("AMF"), Access Network ("AN"), Access Point ("AP"), Authentication Server Function ("AUSF"), Beam Failure Detection ("BFD"), Binary Phase Shift Keying ("BPSK"), Base Station ("BS"), Buffer Status Report ("BSR"), Bandwidth ("BW"), Bandwidth Part ("BWP"), Carrier Aggregation ("CA"), Contention-Based Random Access ("CBRA"), Clear Channel Assessment ("CCA"), Control Channel Element ("CCE"), Cyclic Delay Diversity ("CDD"), Code Division Multiple Access ("CDMA"), Control Element ("CE"), Contention-Free Random Access ("CFRA"), Closed-Loop ("CL"), Coordinated Multipoint ("CoMP"), Cyclic Prefix ("CP"), Cyclical Redundancy Check ("CRC"), Channel State Information ("CSI"), Channel State Information-Reference Signal ("CSI-RS"), Candidate Single-subframe Resources ("CSRs"), Common Search Space ("CSS"), Control Resource Set ("CORESET"), Device-to-Device ("D2D"), Discrete Fourier Transform Spread ("DFTS"), Downlink Control Information ("DCI"), Downlink ("DL"), Demodulation Reference Signal ("DMRS"), Data Radio Bearer ("DRB"), Discontinuous Reception ("DRX"), Downlink Pilot Time Slot ("DwPTS"), Enhanced Clear Channel Assessment ("eCCA"), EPS Connection Management ("ECM"), Enhanced Mobile Broadband ("eMBB"), Evolved Node B ("eNB"), Effective Isotropic Radiated Power ("EIRP"), European Telecommunications Standards Institute ("ETSI"), Evolved Packet Core ("EPC"), Evolved Packet System ("EPS"), Evolved Universal Terrestrial Access ("E-UTRA"), Evolved Universal Terrestrial Access Network ("E-UTRAN"), Frame Based Equipment ("FBE"), Frequency Division Duplex ("FDD"), Frequency Division Multiplexing ("FDM"), Frequency Division Multiple Access ("FDMA"), Frequency Division Orthogonal Cover Code ("FD-OCC"), <NUM> Node B or Next Generation Node B ("gNB"), Group Leader ("GL"), General Packet Radio Services ("GPRS"), Guard Period ("GP"), Global System for Mobile Communications ("GSM"), Globally Unique Temporary UE Identifier ("GUTI"), Home AMF ("hAMF"), Hybrid Automatic Repeat Request ("HARQ"), Home Location Register ("HLR"), Home PLMN ("HPLMN"), Home Subscriber Server ("HSS"), Identity or Identifier ("ID"), Information Element ("IE"), International Mobile Equipment Identity ("IMEI"), International Mobile Subscriber Identity ("IMSI"), International Mobile Telecommunications ("IMT"), Internet-of-Things ("IoT"), Intelligent Transportation Systems Application Identifier ("ITS-AID"), Layer <NUM> ("L1"), Layer <NUM> ("L2"), Layer <NUM> ("L3"), Licensed Assisted Access ("LAA"), Load Based Equipment ("LBE"), Listen-Before-Talk ("LBT"), Logical Channel ("LCH"), Logical Channel Prioritization ("LCP"), Log-Likelihood Ratio ("LLR"), Long Term Evolution ("LTE"), Multiple Access ("MA"), Medium Access Control ("MAC"), Multimedia Broadcast Multicast Services ("MBMS"), Minimum Communication Range ("MCR"), Modulation Coding Scheme ("MCS"), Master Information Block ("MIB"), Multiple Input Multiple Output ("MIMO"), Mobility Management ("MM"), Mobility Management Entity ("MME"), Mobile Network Operator ("MNO"), massive MTC ("mMTC"), Maximum Power Reduction ("MPR"), Machine Type Communication ("MTC"), Multi User Shared Access ("MUSA"), Non Access Stratum ("NAS"), Narrowband ("NB"), Negative-Acknowledgment ("NACK") or ("NAK"), Network Entity ("NE"), Network Function ("NF"), Next Generation RAN ("NG-RAN"), Non-Orthogonal Multiple Access ("NOMA"), New Radio ("NR"), Network Repository Function ("NRF"), Network Slice Instance ("NSI"), Network Slice Selection Assistance Information ("NSSAI"), Network Slice Selection Function ("NSSF"), Network Slice Selection Policy ("NSSP"), Operation and Maintenance System ("OAM"), Orthogonal Frequency Division Multiplexing ("OFDM"), Open-Loop ("OL"), Other System Information ("OSI"), Power Angular Spectrum ("PAS"), Physical Broadcast Channel ("PBCH"), Power Control ("PC"), LTE-to-V2X Interface ("PC5"), Primary Cell ("PCell"), Policy Control Function ("PCF"), Physical Cell ID ("PCID"), Physical Downlink Control Channel ("PDCCH"), Packet Data Convergence Protocol ("PDCP"), Physical Downlink Shared Channel ("PDSCH"), Pattern Division Multiple Access ("PDMA"), Packet Data Unit ("PDU"), Physical Hybrid ARQ Indicator Channel ("PHICH"), Power Headroom ("PH"), Power Headroom Report ("PHR"), Physical Layer ("PHY"), Platoon Leader ("PL"), Public Land Mobile Network ("PLMN"), Platoon Member ("PM"), Physical Random Access Channel ("PRACH"), Physical Resource Block ("PRB"), Primary Secondary Cell ("PSCell"), Physical Sidelink Control Channel ("PSCCH"), Physical Sidelink Feedback Channel ("PSFCH"), Provider Service Identifier ("PSID"), Physical Uplink Control Channel ("PUCCH"), Physical Uplink Shared Channel ("PUSCH"), Quasi Co-Located ("QCL"), Quality of Service ("QoS"), Quadrature Phase Shift Keying ("QPSK"), Registration Area ("RA"), Radio Access Network ("RAN"), Radio Access Technology ("RAT"), Random Access Procedure ("RACH"), Random Access Response ("RAR"), Resource Element Group ("REG"), Radio Link Control ("RLC"), Radio Link Monitoring ("RLM"), Radio Network Temporary Identifier ("RNTI"), Reference Signal ("RS"), Remaining Minimum System Information ("RMSI"), Radio Resource Control ("RRC"), Radio Resource Management ("RRM"), Resource Spread Multiple Access ("RSMA"), Reference Signal Received Power ("RSRP"), Round Trip Time ("RTT"), Receive ("RX"), Sparse Code Multiple Access ("SCMA"), Scheduling Request ("SR"), Sounding Reference Signal ("SRS"), Single Carrier Frequency Division Multiple Access ("SC-FDMA"), Secondary Cell ("SCell"), Shared Channel ("SCH"), Sidelink Control Information ("SCI"), Sub-carrier Spacing ("SCS"), Service Data Unit ("SDU"), System Information Block ("SIB"), SystemInformationBlockType1 ("SIB <NUM>"), SystemInformationBlockType2 ("SIB2"), Subscriber Identity/Identification Module ("SIM"), Signal-to-Interference-Plus-Noise Ratio ("SINR"), Sidelink ("SL"), Service Level Agreement ("SLA"), Sidelink Slot Format Indicator ("SL-SFI"), Session Management Function ("SMF"), Special Cell ("SpCell"), Single Network Slice Selection Assistance Information ("S-NSSAI"), Shortened TTI ("sTTI"), Semi-Persistent Scheduling ("SPS"), Sidelink RSRP ("S-RSRP"), Synchronization Signal ("SS"), Synchronization Signal Block ("SSB"), Scheduling UE ("SUE"), Supplementary Uplink ("SUL"), Subscriber Permanent Identifier ("SUPI"), Candidate Resource Selection Time Window ("T2"), Tracking Area ("TA"), TA Indicator ("TAI"), Transport Block ("TB"), Transport Block Size ("TBS"), Time-Division Duplex ("TDD"), Time Division Multiplex ("TDM"), Time Division Orthogonal Cover Code ("TD-OCC"), Transmission Power Control ("TPC"), Transmission Reception Point ("TRP"), Transmission Time Interval ("TTI"), Time to Live ("TTL"), Transmit ("TX"), Uplink Control Information ("UCI"), Unified Data Management Function ("UDM"), Unified Data Repository ("UDR"), User Entity/Equipment (Mobile Terminal) ("UE"), Universal Integrated Circuit Card ("UICC"), Uplink ("UL"), Universal Mobile Telecommunications System ("UMTS"), User Plane ("UP"), Uplink Pilot Time Slot ("UpPTS"), Ultra-reliability and Low-latency Communications ("URLLC"), UE Route Selection Policy ("URSP"), LTE Radio Interface ("Uu"), Vehicle-To-Everything ("V2X"), Visiting AMF ("vAMF"), Visiting NSSF ("vNSSF"), Visiting PLMN ("VPLMN"), Interconnecting Interface ("X2") ("Xn"), and Worldwide Interoperability for Microwave Access ("WiMAX").

In certain wireless communications networks, sidelink communication may be used. In such networks, half duplex sidelink communication may be used and some communications may not be properly received because of the half duplex sidelink communication.

<NPL>, provides views on various aspects of sidelink PHY layer procedure, including sidelink HARQ procedure, sidelink CSI acquisition, multi-antenna based transmission and sidelink power control.

<NPL>, discusses the physical layer procedures of NR-V2X sidelink, such as feedback mechanism, multiple antenna transmission for PSCCH and PSSCH and power control.

<NPL>, provides a summary of major sidelink resource allocation aspects for NR-V2X sidelink communication design.

Methods for using a configured feedback resource for feedback are disclosed. Apparatuses and systems also perform the functions of the method.

<FIG> depicts an embodiment of a wireless communication system <NUM> for using a configured feedback resource for feedback. In one embodiment, the wireless communication system <NUM> includes remote units <NUM> and network units <NUM>. Even though a specific number of remote units <NUM> and network units <NUM> are depicted in <FIG>, one of skill in the art will recognize that any number of remote units <NUM> and network units <NUM> may be included in the wireless communication system <NUM>.

In one embodiment, the remote units <NUM> may include computing devices, such as desktop computers, laptop computers, personal digital assistants ("PDAs"), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), aerial vehicles, drones, or the like. The remote units <NUM> may communicate directly with one or more of the network units <NUM> via UL communication signals. The remote units <NUM> may also communicate directly with one or more of the other remote units <NUM>.

In one embodiment, a remote unit <NUM> may transmit, to a device, configuration information on a transmission resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource. In certain embodiments, the remote unit <NUM> may monitor for feedback from the device on the feedback resource. In various embodiments, the remote unit <NUM> may transmit the data transmission after the monitoring for feedback on the feedback resource. Accordingly, the remote unit <NUM> may be used for using a configured feedback resource for feedback.

In another embodiment, a remote unit <NUM> may receive, at a device, configuration information on a reception resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource. In certain embodiments, the remote unit <NUM> may determine whether to transmit feedback on the feedback resource. In some embodiments, the remote unit <NUM> may, in response to determining to transmit the feedback on the feedback resource, transmit the feedback from the device on the feedback resource. In various embodiments, the remote unit <NUM> may receive the data transmission after the feedback resource. Accordingly, the remote unit <NUM> may be used for using a configured feedback resource for feedback.

In one embodiment, a remote unit <NUM> may receive, at a device, a data transmission via sidelink transmission. In certain embodiments, the remote unit <NUM> may determine whether a half duplex problem exists with the data transmission. In some embodiments, the remote unit <NUM> may, in response to determining that the half duplex problem exists with the data transmission, retransmit the data transmission. Accordingly, the remote unit <NUM> may be used for retransmitting data.

<FIG> depicts one embodiment of an apparatus <NUM> that may be used for using a configured feedback resource for feedback. The apparatus <NUM> includes one embodiment of the remote unit <NUM>. Furthermore, the remote unit <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, a transmitter <NUM>, and a receiver <NUM>. In some embodiments, the input device <NUM> and the display <NUM> are combined into a single device, such as a touchscreen. In certain embodiments, the remote unit <NUM> may not include any input device <NUM> and/or display <NUM>. In various embodiments, the remote unit <NUM> may include one or more of the processor <NUM>, the memory <NUM>, the transmitter <NUM>, and the receiver <NUM>, and may not include the input device <NUM> and/or the display <NUM>.

In various embodiments, the processor <NUM> monitors for feedback from the device on the feedback resource. In certain embodiments, the processor <NUM> determines whether to transmit feedback on the feedback resource. In some embodiments, the processor <NUM> determines whether a half duplex problem exists with the data transmission.

The transmitter <NUM> is used to provide UL communication signals to the network unit <NUM> and the receiver <NUM> is used to receive DL communication signals from the network unit <NUM>, as described herein. In some embodiments, the transmitter <NUM>: transmits, to a device, configuration information on a transmission resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource; and transmits the data transmission after the monitoring for feedback on the feedback resource.

In various embodiments, the receiver <NUM> receives configuration information on a reception resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource. In some embodiments, the transmitter <NUM>, in response to the processor determining to transmit the feedback on the feedback resource, transmits the feedback from the apparatus on the feedback resource. In various embodiments, the receiver <NUM> receives the data transmission after the feedback resource.

In some embodiments, the receiver <NUM> receives a data transmission via sidelink transmission. In certain embodiments, the transmitter <NUM>, in response to determining that the half duplex problem exists with the data transmission, retransmits the data transmission.

<FIG> depicts one embodiment of an apparatus <NUM> that may be used for using a configured feedback resource for feedback. The apparatus <NUM> includes one embodiment of the network unit <NUM>. Furthermore, the network unit <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, a transmitter <NUM>, and a receiver <NUM>. As may be appreciated, the processor <NUM>, the memory <NUM>, the input device <NUM>, the display <NUM>, the transmitter <NUM>, and the receiver <NUM> may be substantially similar to the processor <NUM>, the memory <NUM>, the input device <NUM>, the display <NUM>, the transmitter <NUM>, and the receiver <NUM> of the remote unit <NUM>, respectively.

In some embodiments, the transmitter <NUM> may transmit configuration information. Although only one transmitter <NUM> and one receiver <NUM> are illustrated, the network unit <NUM> may have any suitable number of transmitters <NUM> and receivers <NUM>.

In certain embodiments, such as for distributed resource allocation, half duplex constraints may limit a time at which UEs can transmit to enable all UEs in a group to receive the transmission from the UE. In some embodiments, two UEs may transmit using a same time and/or frequency resource block or timeslot (e.g., with different frequency resource) and the resources may be used for several transmissions via a SPS allocation before a reselection. In such embodiments, several transmissions of the two UEs may have a half duplex problem or resource collision (e.g., if they select the same resource).

<FIG> is a schematic block diagram illustrating one embodiment of a system <NUM> including multiple UEs transmitting at the same time and different frequencies. The system <NUM> includes a first UE <NUM>, a second UE <NUM>, and a third UE <NUM>. The first UE <NUM> and the second UE <NUM> may transmit data at the same time <NUM>, but on different frequencies <NUM>. Moreover, the third UE <NUM> may receive both transmissions from the first UE <NUM> and the second UE <NUM> because the transmissions are on different frequencies <NUM>. As may be appreciated, if the UEs operate in a half duplex mode, they may not be able to transmit and receive at the same time. Accordingly, while the first UE <NUM> and the second UE <NUM> are transmitting data simultaneously, they are not able to receive data (e.g., receive the data transmitted from the other transmitting UE).

In some embodiments, there may be two SL resource allocation modes: Mode <NUM> in which a BS schedules SL resources to be used by a UE for SL transmissions; and Mode <NUM> in which a UE determines (e.g., the BS does not schedule) SL transmission resources within SL resources configured by a BS and/or network or preconfigured SL resources.

In certain embodiments, the definition of SL resource allocation Mode <NUM> covers: a) UE autonomously selects SL resource for transmission; b) UE assists SL resource selection for other UEs, a functionality which can be part of a), c), and/or d); c) UE is configured with NR configured grant (Type-<NUM> like) for SL transmission; and d) UE schedules SL transmissions of other UEs.

In various embodiments, resource allocation Mode <NUM> supports reservation of SL resources at least for blind retransmission. In one embodiment, sensing and resource selection (or reselection) related procedures may be supported for resource allocation Mode <NUM>.

In some embodiments, a sensing procedure considered may be defined as decoding SCI from other UEs and/or SL measurements. Decoding SCI may provide information on SL resources indicated by a UE transmitting the SCI. The sensing procedure may use a L1 SL RSRP measurement based on SL DMRS if a corresponding SCI is decoded.

In certain embodiments, a resource selection (or reselection) procedure considered may use the results of a sensing procedure to determine resources for SL transmission.

In one embodiment, in Mode <NUM>(a), for SL sensing and resource selection procedures, in the context of a semi-persistent scheme in which resources are selected for multiple transmissions of different TBs and a dynamic scheme in which resources are selected for each TB transmission, the following techniques may be used to identify occupied SL resources: decoding of SL control channel transmissions; SL measurements; and/or detection of SL transmissions. Moreover, the following aspects may be used for SL resource selection: how a UE selects resources for PSCCH and PSSCH transmission (and other SL physical channels and/or signals that are defined); and/or what information is used by the UE for a resource selection procedure.

In some embodiments, for out-of-coverage operation, Mode <NUM>(c) may assume a configuration (or pre-configuration) of single or multiple SL transmission patterns defined on each SL resource pool. In certain embodiments, for in-coverage operation, Mode <NUM>(c) may assume that a gNB configuration indicates single or multiple SL transmission patterns defined on each SL resource pool. In various embodiments, if there is a single pattern configured for a transmitting UE, there may be no sensing procedure executed by the UE if multiple patterns are configured and there may be a possibility of a sensing procedure. As used herein, a "pattern" may be defined by a size and/or position of resources in time and/or frequency, and by a number of resources.

In various embodiments, for Mode <NUM>(d), in the context of group-based SL communication, a UE-A may inform its serving gNB about members UE-B, UE-C, and so on of a group, and the gNB may provide individual resource pool configurations and/or individual resource configurations to each group member through UE-A. In such embodiments, UE-A cannot modify the configurations, and there is no direct connection required between any member UE and the gNB. Moreover, in such embodiments, higher-layer signaling may be the only signaling used to provide the configurations and such functionality may be up to UE capabilities.

In certain embodiments, in the context of Mode-<NUM>(d), NR V2X may support the following functionality: a UE informs a gNB about group members and the gNB provides individual resource pool configuration and/or individual resource configuration through the same UE to each group member UE within the same group. This may not require a connection between a member UE and the gNB. The UE may not modify the configuration provided by gNB, higher layer signaling may be used to provide the configuration, and no physical layer signaling may be used; FFS if one or both of the following options are supported - resource pool configurations and/or resource configuration; FFS if functionality is defined as a part of Mode-<NUM> if applicable for this feature; and/or functionality up to UE capabilities.

In certain embodiments, a UE may determine a set of resources to be reported to higher layers for PSSCH transmission if requested by higher layers in subframe n for a carrier according to the following steps: <NUM>) an interval between n + T<NUM> and n + T<NUM> may be a selection window. In this window, CSRs may be selected after filtering out unusable resources. First, a UE marks those subframe resources as unavailable if the UE has been transmitting in those subframes because the subframes at which a UE has transmitted its packet may not be sensed by itself due to half-duplex transmission. Secondly, the UE excludes resources that are probably used by other UEs, whether a resource was used or not may be determined by decoding PSCCH following steps: based on a resource reservation and priority field in an SCI format <NUM>; and/or based on a measured S-RSRP higher than the configured threshold. After excluding resources based on above factors, the remaining resources are called a set SA; and <NUM>) if single-subframe resources in SA are less than <NUM>% of the entire selection window, then more candidate resources should be identified. For this, we raise the RSRP threshold by <NUM> dB, and repeat the above resource exclusion process. If SA becomes larger than <NUM>%, then we choose those with the smallest RSSI values, which we call SB and report SB to the MAC, where it randomly selects one of them for the transmission. UE selection of T2 value for candidate resource selection may fulfill a latency requirement.

In various embodiments, one embodiment of content of SCI format <NUM> used to schedule PSSCH is shown in Table1.

It should be noted that as used herein, eNB and/or gNB may be used for a base station but may also be replaceable by any other radio access node (e.g., BS, eNB, gNB, AP, NR, etc). Furthermore, methods described herein may be described mainly in the context of <NUM> NR, but may be applicable to other mobile communication systems supporting serving cells and/or carriers configured for sidelink communication, such as for systems that communicate over PC5 interface.

<FIG> is a schematic block diagram illustrating one embodiment of a system <NUM> including multiple UEs transmitting at the same time in the same group. The system <NUM> includes a first UE <NUM>, a second UE <NUM>, a third UE <NUM>, a fourth UE <NUM>, and a fifth UE <NUM> all within a group <NUM>.

Specifically, <FIG> illustrates one embodiment of group communication with an NR mode <NUM> based distributed resource allocation scheme in which the first UE <NUM> and the second UE <NUM> transmit using the same time slot (with different frequency resources) and cannot hear each other's transmission and the third UE <NUM> is a SUE that assists group member with resource selection. The selection of SUE may be configured by a BS or a V2X application, and the UE ID of the SUE may be known to the group members.

In a first embodiment, a reliability issue may arise due to a potential half duplex constraint in a groupcast transmission and may be successfully mitigated with the aid of an SUE that periodically monitors SCI transmissions from group member UEs and provides feedback if there is any potential half duplex problem and/or resource collision.

<FIG> is a schematic block diagram illustrating one embodiment of a frame structure <NUM> that may be used to implement the first embodiment. The frame structure <NUM> illustrated with the time domain extending horizontally includes an SCI TX <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted, one or more OFDM symbols) transmitted from a TX UE, a gap <NUM> (e.g., having a gap time period in which there are no UEs transmitting, a set to time domain symbols, a set of OFDM symbols), an SCI RX <NUM> (e.g., one or more time domain symbol in which feedback is received, one or more OFDM symbols) received by the TX UE, and SL data <NUM> (e.g., a data transmission transmitted from the TX UE).

<FIG> is a schematic block diagram illustrating another embodiment of a frame structure <NUM> that may be used to implement the first embodiment. The frame structure <NUM> illustrated with the time domain extending horizontally includes an SCI TX <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted, one or more OFDM symbols) transmitted from a TX UE, an SCI RX <NUM> (e.g., one or more time domain symbol in which feedback is received, one or more OFDM symbols) received by the TX UE, and SL data <NUM> (e.g., a data transmission transmitted from the TX UE).

<FIG> is a schematic block diagram illustrating a further embodiment of a frame structure <NUM> that may be used to implement the first embodiment. The frame structure <NUM> illustrated with the time domain extending horizontally includes an SCI TX <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted, one or more OFDM symbols) transmitted from a TX UE, a gap <NUM> (e.g., having a gap time period in which there are no UEs transmitting, a set to time domain symbols, a set of OFDM symbols), blank symbols <NUM> (e.g., blank symb. , one or more time domain symbol in which feedback is received, one or more OFDM symbols) configured as symbols in which no transmissions occur from the TX UE, and SL data <NUM> (e.g., a data transmission transmitted from the TX UE).

<FIG> is a schematic block diagram illustrating yet another embodiment of a frame structure <NUM> that may be used to implement the first embodiment. The frame structure <NUM> illustrated with the time domain extending horizontally includes an SCI TX <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted, one or more OFDM symbols) transmitted from a TX UE, blank symbols <NUM> (e.g., blank symb. , one or more time domain symbol in which feedback is received, one or more OFDM symbols) configured as symbols in which no transmissions occur from the TX UE, and SL data <NUM> (e.g., a data transmission transmitted from the TX UE).

As illustrated in <FIG>, TX UEs may transmit SCI in a beginning part of the OFDM symbols (e.g., SCI TX) to group member UEs. The SCI transmission may contain resource information for a data transmission, a corresponding destination group identifier, a destination node identifier, an indication for requesting feedback from an SUE, a slot format indicator indicating a time domain symbol for feedback, and/or a feedback resource configuration.

In the subsequent OFDM symbols configured as blank symbols as shown in <FIG> or labeled as SCI RX in <FIG>, the TX UE switches to an RX mode before it transmits SL data. During a time duration of the blank symbols or the SCI RX, the TX UE checks for feedback from an SUE that may indicate whether there is a half duplex problem. The blank symbols are symbols in which TX UEs in a group do not make any transmissions, but instead wait for reception of feedback from an SUE.

Thus, during the blank symbols, TX UEs do not transmit anything, TX UEs are switched to an RX mode, and only the SUE is enabled to transmit feedback during this period. If there is a switching time or gap required then a flexible symbol (or symbols) may be inserted as a gap (e.g., the gap <NUM>, the gap <NUM>) before the blank symbols.

In some embodiments, TX UEs, if configured for half duplex detection, may select transmission resources from transmit resource pools. The selection may be based on the reliability and/or latency requirement of a groupcast packet transmission.

In certain embodiments, TX UEs may indicate configuration information for a feedback transmission that will be transmitted by an SUE. The indication of the configuration information may be made dynamically in SCI, semi-statically in PC5 RRC, and/or by a gNB via RRC. One embodiment of configuration information is shown in Table <NUM>. In various embodiments, the configuration information includes: a flag to indicate a request for half duplex detection, a time domain symbol for transmission of the feedback message by the SUE, a feedback timing, a feedback resource, an offset for the transmission of the feedback message by the SUE, a resource option to be used by the SUE (e.g., a common feedback resource, a dedicated feedback resource), a number of blank symbols, and/or a number of OFDM symbols that create a switching gap.

In various embodiments, TX UEs receive feedback (e.g., a feedback indicator, a feedback message) and/or additional scheduling assistance information from an SUE as shown in Table <NUM> in response to transmitting SCI. In such embodiments, the TX UEs may transmit based on the scheduling assistance information provided in the feedback message by the SUE that may be based on a random back off timer. Table <NUM> shows one embodiment of a feedback message that include a half duplex detection indicator, and instructions for a TX UE with an identified source ID to transmit on a particular time slot or using an indicated offset. As may be appreciated, the feedback message may include information for two or more TX UEs that desire to transmit information at the during the same time resources in order to assign the TX UEs different time resources so that their transmissions do not occur at the same time.

In some embodiments, if a TX UE transmits a message requesting feedback from an SUE corresponding to half duplex detection and the TX UE does not detect a feedback message that includes the feedback during a configured time period, the TX UE may based on its own remaining packet delay budget and/or priority determine to transmit the SL data in the same time slot that it originally planned to or transmit the SL data in a different time slot based on a random back off timer.

In certain embodiments, if a TX UE transmits a message requesting feedback from an SUE corresponding to half duplex detection and the TX UE receives on a common feedback resource, then, if the common feedback resource indicates detection of a half duplex problem, the TX UE may transmit SL data after a random back off timer.

In various embodiments, one RX UE may be configured as an SUE. In such embodiments, the SUE may monitor SCI transmission from multiple TX UEs in a group, the SUE may periodically monitor, receive, and/or decode SCI transmitted from group member UEs in a configured resources as part of a sensing procedure, the SUE may transmit feedback in configured blank symbols to the TX UEs about a half duplex problem detection and/or resource collision. In some embodiments, if an SUE receives one or more SCI transmission from group member UEs in the same or different OFDM symbols of a time slot, the SUE may check one or more destination group identifiers and/or a resource selected for SL data transmission by group member UEs from their SCI.

In certain embodiments, if a destination group identifier indicated by group member TX UEs is identical and/or a resource selected by the group member TX UEs occupies the same time slot, then there is a potential half duplex problem and an SUE may provide feedback with a corresponding indication to the TX UEs.

In various embodiments, if a destination group identifier indicated by group member TX UEs is not identical and/or a resource selected by the group member TX UEs do not occupy the same time slot, then there is no half duplex problem and an SUE may provide feedback to the TX UEs that indicates that there is no half duplex problem.

In some embodiments, if a destination group identifier indicated by group member TX UEs is not identical and/or a resource selected by the group member TX UEs occupies the same time slot, then there is a potential half duplex problem and an SUE may (or may not) provide feedback with a corresponding indication to the TX UEs.

In certain embodiments, an SUE, based on a received feedback configuration from TX UEs, may select a resource based on a corresponding feedback option and may transmit feedback in a common feedback resource and/or a dedicated feedback resource to TX UEs based on a number of TX UEs transmitting in a time slot. The number of TX UEs transmitting in a time slot may be determined based on SCI reception.

In various embodiments, an SUE may be configured to transmit feedback only if there is a half duplex problem detected and may provide no feedback transmission if there is no half duplex problem detected.

In some embodiments, a feedback transmission (e.g., feedback message) transmitted from an SUE may be carried by a PSCCH in the SCI RX shown in <FIG> or in the blank symbols shown in <FIG>. Table <NUM> shows one embodiment of information that may be included in a feedback message. For example, the feedback message may include: an indicator based on a flag or a bit that provides feedback information (e.g., '<NUM>' for no half duplex problem and '<NUM>' for half duplex problem detection); and or source IDs of TX UEs for each TX UE or group IDs if a common feedback resource is used.

In certain embodiments, an SUE may provide additional assistance information such as different time slots or OFDM symbols configuration to TX UEs to facilitate avoiding a problem in the same or subsequent transmissions. In one embodiment, based on a priority indicated by TX UEs in SCI, an SUE that detects a half duplex problem may provide feedback to one TX UE to transmit in an originally planned time slot and/or symbols and may provide feedback to another TX UE to transmit in a different non-overlapping time slot and/or symbols.

In various embodiments, a BS may configure separate resource pools with blank symbols as described in relation to <FIG>. In such embodiments, the BS may broadcast the configuration of the resource pools as part of a system information block and/or the configuration may be configured (or preconfigured) for NR Mode <NUM> operations. In such embodiments, the configuration of the resource pools by the gNB or the otherwise provided configuration (or preconfiguration) may contain an indication of one or more time domain symbols for: SCI transmission, blank symbols, SL data transmission, and/or sidelink HARQ feedback.

In some embodiments, configuration of a sidelink frame structure indicating blank symbols may be indicated by: a SL-SFI by a gNB in DCI (e.g., format 5A), a system information block for sidelink, an RRC configuration for sidelink, and/or other sidelink UEs either in SCI or PC5 RRC. As may be appreciated, configured blank symbols may be for a group of UEs in a cell or for certain geographical areas. In certain embodiments, flexible symbols may be explicitly configured as blank symbols. As may be appreciated, a flexible symbol may be an OFDM symbol in a slot that may be configured as DL, UL, SL, and/or a blank symbol. In various embodiments, a configuration that enables half duplex detection may be configured by a BS.

While <FIG>, <FIG> illustrate certain examples of frames structures used to implement the first embodiment, other frame structures may also be used. For example, <FIG> is a schematic block diagram illustrating an additional embodiment of a frame structure <NUM> that may be used to implement the first embodiment.

The frame structure <NUM> is illustrated with the time domain extending horizontally and includes a first slot (N) <NUM> and a second slot (N+<NUM>) <NUM>. The first slot (N) <NUM> includes an SCI TX (N) <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted in slot N, one or more OFDM symbols transmitted in slot N) transmitted from a TX UE, SL Data (N-<NUM>) <NUM> (e.g., a data transmission transmitted from the TX UE that corresponds to configuration information transmitted in slot N-<NUM> - the slot that would precede the first slot (N) <NUM>), and PSFCH (N) <NUM> (e.g., one or more time domain symbol in which feedback is received that corresponds to SCI TX (N) <NUM>, one or more OFDM symbols in which feedback is received that corresponds to SCI TX (N) <NUM>). The second slot (N+<NUM>) <NUM> includes an SCI TX (N+<NUM>) <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted in slot N+<NUM>, one or more OFDM symbols transmitted in slot N+<NUM>) transmitted from a TX UE, SL Data (N) <NUM> (e.g., a data transmission transmitted from the TX UE that corresponds to configuration information transmitted in the first slot (N) <NUM>), and PSFCH (N+<NUM>) <NUM> (e.g., one or more time domain symbol in which feedback is received that corresponds to SCI TX (N+<NUM>) <NUM>, one or more OFDM symbols in which feedback is received that corresponds to SCI TX (N+<NUM>) <NUM>). As may be appreciated, based on the feedback provided in PSFCH (N) <NUM>, the TX UE may determine whether to transmit the SL data (N) <NUM> in the second slot (N+<NUM>) <NUM>. In another method, the feedback may be transmitted for the SL data (N) with PSFCH in the same time slot as illustrated in <FIG>.

<FIG> is a schematic block diagram illustrating another embodiment of a frame structure <NUM> that may be used to implement the first embodiment.

The frame structure <NUM> is illustrated with the time domain extending horizontally and includes a first slot (N) <NUM> and a second slot (N+<NUM>) <NUM>. The first slot (N) <NUM> includes an SCI TX (N) <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted in the first slot (N) <NUM>, one or more OFDM symbols transmitted in the first slot (N) <NUM>) transmitted from a TX UE, SL Data (N) <NUM> (e.g., a data transmission transmitted from the TX UE that corresponds to configuration information transmitted in the first slot (N) <NUM>), and PSFCH (N) <NUM> (e.g., one or more time domain symbol in which feedback is received that corresponds to SCI TX (N) <NUM>, one or more OFDM symbols in which feedback is received that corresponds to SCI TX (N) <NUM>). The second slot (N+<NUM>) <NUM> includes an SCI TX (N+<NUM>) <NUM> (e.g., one or more time domain symbols in which configuration information is transmitted in the second slot (N+<NUM>) <NUM>, one or more OFDM symbols transmitted in the second slot (N+<NUM>) <NUM>) transmitted from a TX UE, SL Data (N+<NUM>) <NUM> (e.g., a data transmission transmitted from the TX UE that corresponds to configuration information transmitted in the second slot (N+<NUM>) <NUM>), and PSFCH (N+<NUM>) <NUM> (e.g., one or more time domain symbol in which feedback is received that corresponds to SCI TX (N+<NUM>) <NUM>, one or more OFDM symbols in which feedback is received that corresponds to SCI TX (N+<NUM>) <NUM>).

<FIG> is a schematic block diagram illustrating one embodiment of communications <NUM> corresponding to group transmissions. The communications <NUM> may include communications between a gNB <NUM>, an SUE <NUM>, and group UEs <NUM>. As may be appreciated, descriptions of communications contained herein may refer to one or more messages transmitted between devices.

In one embodiment, in a first communication <NUM> transmitted from the gNB <NUM> to the SUE <NUM>, the gNB <NUM> may transmit a configuration message to the SUE <NUM> to indicate a configuration for SCI and/or a feedback message. In some embodiments, in a second communication <NUM> transmitted between the SUE <NUM> and the group UEs <NUM>, the configuration message may be provided from the SUE <NUM> to the group UEs <NUM>. In certain embodiments, in a third communication <NUM> transmitted between the group UEs <NUM> and the SUE <NUM>, one or more of the group UEs <NUM> may transmit SCI for groupcast data. In various embodiments, in a fourth communication <NUM> transmitted from the SUE <NUM> to the group UEs <NUM>, the SUE <NUM> may provide a feedback message corresponding to the SCI to the group UEs <NUM> (e.g., to the TX UEs). In some embodiments, in a fifth communication <NUM> transmitted between the group UEs <NUM> and the SUE <NUM>, groupcast data may be transmitted by one or more TX UEs of the group UEs <NUM>.

In a second embodiment, a feedback message may be sent by any UE in a UE group (e.g., not just an SUE). In some cases, a gNB may configure a threshold based on an L1 sidelink RSRP or a configured (or preconfigured) threshold, and a feedback transmission may be transmitted by UEs that are above the configured threshold.

The feedback message may be sent using dedicated L1 signaling to indicate half duplex detection to TX UEs. In one embodiment, the L1 signaling may use PSFCH or PSCCH (e.g., SCI) transmission resources. In certain embodiments, feedback resource configuration may be transmitted by a gNB and/or an SUE. In various embodiments, if PSFCH is used, a common or dedicated feedback configuration may be used.

In some embodiments, if a group member UE detects a half duplex problem as one or more TX UEs are transmitting in the same time slot, even if SL data (e.g., PSSCH) is successfully decoded, the group member UEs may transmit one or more NACKs in a common or dedicated feedback resource to implicitly indicate a potential half duplex problem and the one or more TX UEs may transmit (or retransmit) a corresponding transport block based on the feedback.

In a third embodiment, an RX UE configured as a SUE may: monitor SCI transmissions from multiple TX UEs from a group, receive and/or decode SCI transmitted from group member UEs in configured resources as part of a sensing procedure, and transmit (or retransmit) a group packet to the TX UEs if a half duplex problem is detected and/or a resource collision is detected. Thus, the SUE may directly retransmit the simultaneously transmitted data so that TX UEs do not have to schedule retransmission of the data as in other embodiments. For the transmission (or retransmission), the SUE may use a source ID of the TX UEs as found in L1 and/or L2 signaling.

In certain embodiments, a TX UE may indicate in SCI about a request for half duplex detection and transmission (or retransmission) by an SUE. The TX UEs may reserve a time slot and/or resource for transmission (or retransmission) by the SUE and may indicate the reservation in SCI.

In a fourth embodiment, a sensing method for selecting candidate resources may be improved based on TX UEs receiving feedback messages for half duplex detection. For example, in a resource exclusion process, if a requested or configured feedback message successfully indicates to one or more TX UEs that there is no half duplex problem, then the candidate resources for that time slot (e.g., the time slot in which feedback is requested) is included in the candidate resource selection process.

In some embodiments, if a feedback message indicates a half duplex problem, then there may be a potential transmission from other member UEs in the same time slot, however candidate resource selection process may also depend on a potential resource collision detection with the same or overlapping frequency resources. A determination of whether the resources selected by two or more TX UEs collide (or not) may be based on assistance signaling either from group member UEs or an SUE using L1 signaling, such as PSCCH or PSFCH.

<FIG> is a flow chart diagram illustrating one embodiment of a method <NUM> for using a configured feedback resource for feedback. In some embodiments, the method <NUM> is performed by an apparatus, such as the remote unit <NUM>. In certain embodiments, the method <NUM> may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> may include transmitting <NUM>, to a device, configuration information on a transmission resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource. In certain embodiments, the method <NUM> includes monitoring <NUM> for feedback from the device on the feedback resource. In various embodiments, the method <NUM> includes transmitting <NUM> the data transmission after the monitoring for feedback on the feedback resource.

In certain embodiments, a gap time period in terms of time domain symbols occurs between a time domain symbol in which the configuration information is transmitted and a time domain symbol in which the feedback is received. In some embodiments, the feedback resource is received in a time domain symbol directly after a time domain symbol in which the configuration information is transmitted. In various embodiments, the feedback indicates whether there is a half duplex problem detection, a resource collision, or a combination thereof.

In one embodiment, the configuration of the feedback resource comprises information indicating a time domain symbol for the feedback. In certain embodiments, the feedback resource comprises orthogonal frequency division multiplexed symbols configured as blank symbols. In some embodiments, no transmissions are made on the blank symbol except the feedback transmission made by the device.

In various embodiments, the method <NUM> further comprises selecting the transmission resource and the feedback resource from a resource pool. In one embodiment, transmitting the configuration information comprises transmitting the configuration information within sidelink control information, transmitting the configuration information using a radio resource control message, receiving the configuration message as part of downlink control information, receiving the configuration message as part of radio resource control information, or some combination thereof. In certain embodiments, the feedback resource comprises a common feedback resource or a dedicated feedback resource.

In some embodiments, the configuration information comprises an indication of a half duplex problem detection. In various embodiments, transmitting the data transmission comprises transmitting the data transmission based on the feedback corresponding to a half duplex problem detection. In one embodiment, transmitting the data transmission based on the feedback corresponding to the half duplex problem detection comprises transmitting the data transmission based on an indicated time slot in a feedback message or based on a random back off timer.

In certain embodiments, the method <NUM> further comprises, in response to monitoring for the feedback on the feedback resource resulting in not detecting the feedback, transmitting the data transmission based on a random back off timer, a remaining packet delay budget, a priority, or a combination thereof. In some embodiments, transmitting the data transmission based on the random back off timer, the remaining packet delay budget, the priority, or the combination thereof comprises transmitting the data transmission in a prior determined time slot, or transmitting the data transmission in a time slot determined based on a random back off timer. In various embodiments, the device comprises a scheduling user equipment, and the scheduling user equipment belongs to a destination group.

In one embodiment, the device comprises one or more non-scheduling user equipments. In certain embodiments, the data transmission occurs in a slot after the transmission resource and the feedback resource. In some embodiments, the feedback resource is used to carry a negative acknowledgment that indicates detection of a potential half duplex problem.

In various embodiments, the feedback indicates that there is not a half duplex problem detected. In one embodiment, the method <NUM> further comprises transmitting a second data transmission on a second feedback resource.

<FIG> is a flow chart diagram illustrating another embodiment of a method <NUM> for using a configured feedback resource for feedback. In some embodiments, the method <NUM> is performed by an apparatus, such as the remote unit <NUM>. In certain embodiments, the method <NUM> may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> may include receiving <NUM>, at a device, configuration information on a reception resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource. In certain embodiments, the method <NUM> includes determining <NUM> whether to transmit feedback on the feedback resource. In some embodiments, the method <NUM> includes, in response to determining to transmit the feedback on the feedback resource, transmitting <NUM> the feedback from the device on the feedback resource. In various embodiments, the method <NUM> includes receiving <NUM> the data transmission after the feedback resource.

In various embodiments, the transmission resource and the feedback resource are selected from a resource pool. In one embodiment, receiving the configuration information comprises receiving the configuration information within sidelink control information, receiving the configuration information using a radio resource control message, receiving the configuration message as part of downlink control information, receiving the configuration message as part of radio resource control information, or some combination thereof. In certain embodiments, the feedback resource comprises a common feedback resource or a dedicated feedback resource.

In some embodiments, the configuration information comprises an indication of a half duplex problem detection. In various embodiments, receiving the data transmission comprises receiving the data transmission based on the feedback corresponding to a half duplex problem detection. In one embodiment, receiving the data transmission based on the feedback corresponding to the half duplex problem detection comprises receiving the data transmission based on an indicated time slot in a feedback message or based on a random back off timer.

In certain embodiments, the method <NUM> further comprises, in response to determining not to transmit the feedback on the feedback resource, receiving the data transmission based on a random back off timer, a remaining packet delay budget, a priority, or a combination thereof. In some embodiments, receiving the data transmission based on the random back off timer, the remaining packet delay budget, the priority, or the combination thereof comprises receiving the data transmission in a prior determined time slot, or receiving the data transmission in a time slot determined based on a random back off timer. In various embodiments, the device comprises a scheduling user equipment, and the scheduling user equipment belongs to a destination group.

<FIG> is a flow chart diagram illustrating one embodiment of a method <NUM> for retransmitting data. In some embodiments, the method <NUM> is performed by an apparatus, such as the remote unit <NUM>. In certain embodiments, the method <NUM> may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> may include receiving <NUM>, at a device, a data transmission via sidelink transmission. In certain embodiments, the method <NUM> includes determining <NUM> whether a half duplex problem exists with the data transmission. In some embodiments, the method <NUM> includes, in response to determining that the half duplex problem exists with the data transmission, retransmitting <NUM> the data transmission.

In certain embodiments, the device comprises a scheduling user equipment, and the scheduling user equipment belongs to a destination group. In some embodiments, the device comprises a non-scheduling user equipment.

In one embodiment, a method comprises: transmitting, to a device, configuration information on a transmission resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource; monitoring for feedback from the device on the feedback resource; and transmitting the data transmission after the monitoring for feedback on the feedback resource.

In certain embodiments, a gap time period in terms of time domain symbols occurs between a time domain symbol in which the configuration information is transmitted and a time domain symbol in which the feedback is received.

In some embodiments, the feedback resource is received in a time domain symbol directly after a time domain symbol in which the configuration information is transmitted.

In various embodiments, the feedback indicates whether there is a half duplex problem detection, a resource collision, or a combination thereof.

In one embodiment, the configuration of the feedback resource comprises information indicating a time domain symbol for the feedback.

In certain embodiments, the feedback resource comprises orthogonal frequency division multiplexed symbols configured as blank symbols.

In some embodiments, no transmissions are made on the blank symbol except the feedback transmission made by the device.

In various embodiments, the method further comprises selecting the transmission resource and the feedback resource from a resource pool.

In one embodiment, transmitting the configuration information comprises transmitting the configuration information within sidelink control information, transmitting the configuration information using a radio resource control message, receiving the configuration message as part of downlink control information, receiving the configuration message as part of radio resource control information, or some combination thereof.

In certain embodiments, the feedback resource comprises a common feedback resource or a dedicated feedback resource.

In some embodiments, the configuration information comprises an indication of a half duplex problem detection.

In various embodiments, transmitting the data transmission comprises transmitting the data transmission based on the feedback corresponding to a half duplex problem detection.

In one embodiment, transmitting the data transmission based on the feedback corresponding to the half duplex problem detection comprises transmitting the data transmission based on an indicated time slot in a feedback message or based on a random back off timer.

In certain embodiments, the method further comprises, in response to monitoring for the feedback on the feedback resource resulting in not detecting the feedback, transmitting the data transmission based on a random back off timer, a remaining packet delay budget, a priority, or a combination thereof.

In some embodiments, transmitting the data transmission based on the random back off timer, the remaining packet delay budget, the priority, or the combination thereof comprises transmitting the data transmission in a prior determined time slot, or transmitting the data transmission in a time slot determined based on a random back off timer.

In various embodiments, the device comprises a scheduling user equipment, and the scheduling user equipment belongs to a destination group.

In one embodiment, the device comprises one or more non-scheduling user equipments.

In certain embodiments, the data transmission occurs in a slot after the transmission resource and the feedback resource.

In some embodiments, the feedback resource is used to carry a negative acknowledgment that indicates detection of a potential half duplex problem.

In various embodiments, the feedback indicates that there is not a half duplex problem detected.

In one embodiment, the method further comprises transmitting a second data transmission on a second feedback resource.

In one embodiment, an apparatus comprises: a transmitter that transmits, to a device, configuration information on a transmission resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource; and a processor that monitors for feedback from the device on the feedback resource; wherein the transmitter transmits the data transmission after the monitoring for feedback on the feedback resource.

In various embodiments, the processor selects the transmission resource and the feedback resource from a resource pool.

In one embodiment, the apparatus further comprises a receiver, wherein the transmitter transmitting the configuration information comprises the transmitter transmitting the configuration information within sidelink control information, the transmitter transmitting the configuration information using a radio resource control message, the receiver receiving the configuration message as part of downlink control information, the receiver receiving the configuration message as part of radio resource control information, or some combination thereof.

In various embodiments, the transmitter transmitting the data transmission comprises the transmitter transmitting the data transmission based on the feedback corresponding to a half duplex problem detection.

In one embodiment, the transmitter transmitting the data transmission based on the feedback corresponding to the half duplex problem detection comprises the transmitter transmitting the data transmission based on an indicated time slot in a feedback message or based on a random back off timer.

In certain embodiments, in response to the processor monitoring for the feedback on the feedback resource resulting in not detecting the feedback, the transmitter transmits the data transmission based on a random back off timer, a remaining packet delay budget, a priority, or a combination thereof.

In some embodiments, the transmitter transmitting the data transmission based on the random back off timer, the remaining packet delay budget, the priority, or the combination thereof comprises the transmitter transmitting the data transmission in a prior determined time slot, or transmitting the data transmission in a time slot determined based on a random back off timer.

In one embodiment, the transmitter transmits a second data transmission on a second feedback resource.

In one embodiment, a method comprises: receiving, at a device, configuration information on a reception resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource; determining whether to transmit feedback on the feedback resource; in response to determining to transmit the feedback on the feedback resource, transmitting the feedback from the device on the feedback resource; and receiving the data transmission after the feedback resource.

In various embodiments, the transmission resource and the feedback resource are selected from a resource pool.

In one embodiment, receiving the configuration information comprises receiving the configuration information within sidelink control information, receiving the configuration information using a radio resource control message, receiving the configuration message as part of downlink control information, receiving the configuration message as part of radio resource control information, or some combination thereof.

In various embodiments, receiving the data transmission comprises receiving the data transmission based on the feedback corresponding to a half duplex problem detection.

In one embodiment, receiving the data transmission based on the feedback corresponding to the half duplex problem detection comprises receiving the data transmission based on an indicated time slot in a feedback message or based on a random back off timer.

In certain embodiments, the method further comprises, in response to determining not to transmit the feedback on the feedback resource, receiving the data transmission based on a random back off timer, a remaining packet delay budget, a priority, or a combination thereof.

In some embodiments, receiving the data transmission based on the random back off timer, the remaining packet delay budget, the priority, or the combination thereof comprises receiving the data transmission in a prior determined time slot, or receiving the data transmission in a time slot determined based on a random back off timer.

In one embodiment, an apparatus comprises: a receiver that receives configuration information on a reception resource, wherein the configuration information comprises: resource information for a data transmission; a request for feedback; and a configuration message indicating configuration of a feedback resource; a processor that determines whether to transmit feedback on the feedback resource; and a transmitter that, in response to the processor determining to transmit the feedback on the feedback resource, transmits the feedback from the apparatus on the feedback resource; wherein the receiver receives the data transmission after the feedback resource.

In some embodiments, no transmissions are made on the blank symbol except the feedback transmission made by the apparatus.

In one embodiment, the receiver receiving the configuration information comprises the receiver receiving the configuration information within sidelink control information, the receiver receiving the configuration information using a radio resource control message, the receiver receiving the configuration message as part of downlink control information, the receiver receiving the configuration message as part of radio resource control information, or some combination thereof.

In various embodiments, the receiver receiving the data transmission comprises the receiver receiving the data transmission based on the feedback corresponding to a half duplex problem detection.

In one embodiment, the receiver receiving the data transmission based on the feedback corresponding to the half duplex problem detection comprises the receiver receiving the data transmission based on an indicated time slot in a feedback message or based on a random back off timer.

In certain embodiments, in response to determining not to transmit the feedback on the feedback resource, the receiver receives the data transmission based on a random back off timer, a remaining packet delay budget, a priority, or a combination thereof.

In some embodiments, the receiver receiving the data transmission based on the random back off timer, the remaining packet delay budget, the priority, or the combination thereof comprises the receiver receiving the data transmission in a prior determined time slot, or receiving the data transmission in a time slot determined based on a random back off timer.

In various embodiments, the apparatus comprises a scheduling user equipment, and the scheduling user equipment belongs to a destination group.

In one embodiment, the apparatus comprises one or more non-scheduling user equipments.

In one embodiment, a method comprises: receiving, at a device, a data transmission via sidelink transmission; determining whether a half duplex problem exists with the data transmission; and in response to determining that the half duplex problem exists with the data transmission, retransmitting the data transmission.

In certain embodiments, the device comprises a scheduling user equipment, and the scheduling user equipment belongs to a destination group.

In some embodiments, the device comprises a non-scheduling user equipment.

In one embodiment, an apparatus comprises: a receiver that receives a data transmission via sidelink transmission; a processor that determines whether a half duplex problem exists with the data transmission; and a transmitter that, in response to determining that the half duplex problem exists with the data transmission, retransmits the data transmission.

In certain embodiments, the apparatus comprises a scheduling user equipment, and the scheduling user equipment belongs to a destination group.

In some embodiments, the apparatus comprises a non-scheduling user equipment.

Claim 1:
A method performed by a user equipment, UE, (<NUM>), the method comprising:
transmitting, to a second UE (<NUM>), configuration information on a transmission resource, wherein the configuration information comprises:
instructions to monitor a physical sidelink control channel indicated by a resource reservation field in an SCI format <NUM> in the configuration information;
a request for feedback; and
a configuration message indicating configuration of a feedback resource;
monitoring for feedback from the second UE (<NUM>) on the feedback resource, wherein the feedback comprises feedback indicating whether there is detection of a half duplex problem;
determining whether to transmit a data transmission based on a result of monitoring for the feedback; and
in response to determining to transmit the data transmission, transmitting, to the second UE, the data transmission after the monitoring for feedback on the feedback resource.