Sidelink configured grant resource configuration and signaling

Abstract

A method for transmitting data via an SL data channel, wherein a transmitting UE and a receiving UE are each provided with a semi-static CG configuration, such that the CG configuration instruction does not need to be transmitted in association with each individual data transmission during the duration for which the CG configuration is applied.

Description

[0001] Cross-referencing related applications

[0002] This application claims the benefit and priority of U.S. Provisional Patent Application No. 62 / 888,416, filed August 16, 2019, entitled "SIDELINK CONFIGURED GRANT RESOURCE CONFIGURATION AND SIGNALLING," and U.S. Patent Application No. 16 / 992,921, filed August 13, 2020, both entitled "SIDELINK CONFIGURED GRANT RESOURCE CONFIGURATION AND SIGNALLING," the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This application relates to methods and apparatus for configuring authorized resources and signaling for sidelink communication. Background Technology

[0004] Vehicle-to-everything (V2X) refers to a communication scenario that can include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-network (V2N) communication, and other scenarios. In V2X, transmission can occur via links between the network and user equipment (UE) (e.g., uplink (UL) and downlink (DL)), or via sidelinks (SL) between UEs. Generally, UE cooperation can be used to improve the reliability, throughput, and capacity of V2X communication and next-generation wireless communication.

[0005] The current Long Term Evolution (LTE) standard defines an LTE V2X transmission scheme that relies on the concept of transmit and receive resource pools (RPs). A resource pool comprises a set of time-frequency resources, which can be continuous or discontinuous in time and / or frequency. A resource pool can consist of sub-channels, where a sub-channel is composed of a set of contiguous resource blocks (RBs) within the same subframe.

[0006] Current LTE V2X transmission schemes include two transmission modes: Mode 3 and Mode 4. In Mode 3, the base station (BS) uses downlink control information (DCI) to dynamically or semi-persistently schedule time-frequency resources (from the UE resource pool) for SL transmission. In Mode 4, the UE randomly selects resources within its transmission reserve (RP).

[0007] In addition to the current LTE V2X standard, new V2X schemes are being developed. For example, the Third Generation Partnership Project (3GPP) is studying Release 16 New Radio (NR) V2X standardization. NR V2X will support two SL transmission modes: NR Mode 1 and NR Mode 2. In NR Mode 1, a BS (e.g., a gNB node or eNB in the case of LTE controlling NR sidelink) controls SL transmissions and specifies the resources that a UE will use for SL transmissions. In NR Mode 2, a UE determines or selects resources in a resource pool.

[0008] Many details regarding SL resource configuration for NR V2X Mode 1 and Mode 2 are to be further studied. Thus, there is a need for systems and methods that enable configuration grant (CG) resource allocation and signaling for sidelink communications in a resource-efficient and reliable manner for NR V2X Mode 1 and Mode 2 applications, among others. SUMMARY

[0009] According to one aspect of the present invention, example embodiments relate to transmitting data by a transmitting UE in a SL data channel without accompanying dynamic scheduling information, in a case where a receiving UE can rely on a previously known sidelink CG configuration. In example embodiments, a Tx UE and a Rx UE are respectively provided with a CG configuration that can be used for multiple SL data transmissions semi-persistently or semi-statically, such that the CG configuration indication does not have to be transmitted in association with each individual data transmission for the duration of application of the CG configuration.

[0010] According to a second example aspect, there is provided a method for transmitting data over a sidelink (SL) data channel, the method comprising: transmitting (Tx) user equipment (UE) transmitting one or more SL data transmissions using SL resources specified by a configuration grant (CG) configuration without transmitting accompanying information indicating the SL resources.

[0011] Optionally, in any of the above aspects, the method comprises, prior to the transmitting, the Tx UE first transmitting information indicating the CG configuration to a receiving (Rx) UE using a SL channel.

[0012] Optionally, in any of the above aspects, the method comprises selecting an updated CG configuration at the UE and transmitting information indicating the updated CG configuration to the Rx UE.

[0013] Optionally, in any of the above aspects, the method comprises transmitting a plurality of SL data transmissions using the SL resources specified by the CG configuration and then transmitting a further plurality of SL data transmissions using SL resources specified by the updated CG configuration.

[0014] Optionally, in any of the above aspects, the method comprises: prior to the first sending, the Tx UE receiving signaling from a base station (BS) indicating the CG configuration.

[0015] Optionally, in any of the above aspects, the first sending of the information indicating the CG configuration to the receiving (Rx) UE is performed in a SL control channel using SCI.

[0016] Optionally, in any of the above aspects, the first sending of the information indicating the CG configuration to the receiving (Rx) UE is performed in the SL channel using radio resource control (RRC) signaling.

[0017] Optionally, in any of the above aspects, the first sending of the information indicating the CG configuration to the receiving (Rx) UE is performed in a physical layer broadcast channel (PSBCH).

[0018] Optionally, in any of the above aspects, the method comprises: prior to the sending, the Tx UE receiving signaling from a base station (BS) indicating the CG configuration; the Rx UE receiving signaling from a base station (BS) indicating the CG configuration.

[0019] According to exemplary aspects, there are provided a Tx UE for performing the method of the above aspects as a transmitting UE, and a Rx UE for receiving transmissions of the method according to the above aspects.

[0020] According to another exemplary aspect, there is provided a method performed at a transmitting (Tx) user equipment (UE) for wireless sidelink (SL) communication, the method comprising: sending a first SL signal to a receiving (Rx) UE, the first SL signal indicating parameters of a configured grant (CG) configuration; sending a plurality of SL data transmissions to the Rx UE in a SL data channel according to the parameters, wherein at least one of the SL data transmissions is sent without an accompanying transmission in a SL control channel indicating the parameters.

[0021] Optionally, in any of the above aspects, the first SL signal comprises sidelink control information (SCI) and is sent in the SL control channel.

[0022] Optionally, in any of the above aspects, the method includes selecting, at the Tx UE, updated CG configuration parameters according to SL channel information perceived by the Tx UE, and transmitting, to the Rx UE, a second SL signal indicating the updated CG configuration parameters. In some examples of the above aspects, the method includes transmitting, to the Rx UE, a plurality of SL data transmissions according to the updated CG configuration parameters, wherein at least one of the SL data transmissions is transmitted without an accompanying transmission indicating the updated CG configuration parameters. In some examples, the updated CG configuration parameters update only a subset of the parameters indicated in the first signal.

[0023] Optionally, in any of the above aspects, the CG configuration relates to a broadcast grant-free (GF) configuration of a plurality of Rx UEs, wherein the first SL signal is transmitted to a plurality of Rx UEs, and: (i) the first SL signal includes sidelink control information (SCI); or (ii) the first SL signal is transmitted using a PSBCH transmission, the method further including transmitting, to the plurality of Rx UEs, a second SL signal in a SL data channel, the second SL signal indicating updated CG configuration parameters.

[0024] Optionally, in any of the above aspects, the CG configuration includes a set of parameters selected from a group consisting of: (1) a destination ID of one or more Rx UEs; (2) a source ID of the Tx UE; (3) a SL data channel time-frequency resource; (4) a modulation and coding scheme (MCS) parameter to be used for SL data transmissions; and (5) a demodulation reference signal (DMRS) parameter.

[0025] Optionally, in any of the above aspects, the Tx UE semi-statically applies the CG configuration such that, for a duration of application of the CG configuration, the parameters are not necessarily transmitted from the Tx UE to the Rx UE in association with each individual SL data transmission.

[0026] Optionally, in any of the above aspects, the Tx UE transmits an indication of one or both of a source ID of the Tx UE and a destination ID of the Rx UE. In some such examples, the Tx UE can transmit the indication of the Rx UE in a SL data channel. In some examples, transmitting the indication can be performed by encoding a medium access control-control element (MAC-CE) indicating one or both of the source ID and the destination ID, and jointly encoding the MAC-CE with payload data in one of the multiple data transmissions. A radio resource control (RRC) signal can be transmitted in a data channel, the signal indicating that the MAC-CE is jointly encoded with the payload data. In other examples, transmitting the indication is performed by transmitting the indication using SL data channel time-frequency resources that are not used for any of the multiple SL data transmissions.

[0027] According to another example aspect, a transmitting (Tx) user equipment (UE) is provided for wireless sidelink (SL) communication with one or more receiving (Rx) UEs. The Tx UE is configured to transmit a first SL signal to the Rx UE, the first SL signal indicating a parameter of a configured grant (CG) configuration, and transmit a plurality of SL data transmissions to the Rx UE in accordance with the parameter, at least one of the SL data transmissions being transmitted without an accompanying transmission in a SL control channel indicating the parameter. In some example embodiments, the Rx UE determines the CG configuration by receiving a sidelink control information (SCI) indicating the CG configuration over a SL control channel, and at least one of the plurality of discontinuous SL data transmissions is received over a SL data channel without an accompanying SCI indicating the CG configuration.

[0028] According to another example aspect, a transmitting (Tx) user equipment (UE) is configured for wireless sidelink (SL) communication with one or more receiving (Rx) UEs, the Tx UE configured to transmit one or more SL data transmissions using SL resources specified by a configured grant (CG) configuration without transmitting accompanying information indicating the SL resources.

[0029] According to another example aspect, a computer program product is disclosed, the computer program product comprising a non-transitory memory storing computer- implementable instructions that cause a transmitting (Tx) user equipment to transmit one or more SL data transmissions using SL resources specified by a configured grant (CG) configuration without transmitting accompanying information indicating the SL resources.

[0030] According to another example aspect, a method for receiving data over a sidelink (SL) data channel is disclosed, comprising: determining, at a receiving (Rx) user equipment (UE), a configured grant (CG) configuration for processing SL data transmissions received by the Rx UE; processing a plurality of discontinuous SL data transmissions using the CG configuration.

[0031] According to another example aspect, a receiving (Rx) user equipment (UE) for receiving wireless sidelink (SL) communications from a transmitting (Tx) UE is disclosed. The Rx UE is configured to: determine a configured grant (CG) configuration for processing SL data transmissions received by the Rx UE; and process a plurality of discontinuous SL data transmissions using the CG configuration. BRIEF DESCRIPTION OF DRAWINGS

[0032] Embodiments of the application will now be described, by way of example only, with reference to the accompanying drawings in which:

[0033] Figure 1 is a block diagram of a communication of a configured grant for sidelink communication provided by an example embodiment;

[0034] Figure 2 is a block diagram of a communication of a configured grant for sidelink communication provided by another example embodiment;

[0035] Figure 3 is a block diagram of a communication of a configured grant for sidelink communication provided by another example embodiment;

[0036] Figure 4 is a block diagram of a communication of a configured grant for sidelink communication provided by another example embodiment;

[0037] Figure 5 is a block diagram of an example of a telecommunications network provided by an embodiment;

[0038] Figure 6 is a block diagram of an example of a network serving two UEs;

[0039] Figure 7 is a flowchart of a process that can be performed by a Tx UE for wireless SL communication provided by an example embodiment;

[0040] Figure 8 is a flowchart of a process that can be performed by a Rx UE for wireless SL communication provided by an example embodiment. DETAILED DESCRIPTION

[0041] Example embodiments are described that generally apply to any communication system in which UEs are semi-statically granted resources for sidelink (SL) communication.

[0042] As noted above, in the context of V2X, SL refers to communication between UEs. For example, such direct UE-to-UE communication can use a PC5 air interface. UE-to-UE SL data transmission involves transmitting data units, e.g., transport blocks (TBs), using a wireless SL data channel, e.g., a physical sidelink shared channel (PSSCH). Generally, the SL data channel is subdivided into a set of transmission resources (e.g., time / frequency resources with corresponding time durations and frequency bandwidths), and these transmission resources are shared by a group of UEs. In a configured grant scenario, a sending UE is assigned a specific set of transmission resources that it can use for SL data transmission over the SL data channel without the need for dynamic scheduling. In cases where a base station indicates the use of SL transmission resources between UEs, the assignment of a set of transmission resources is indicated dynamically through a dynamic grant, or semi-statically through a configured grant (CG). In particular, a SL CG configuration specifies a set of SL resources and other communication parameters that a UE can use.

[0043] A SL CG configuration can include a transmission (Tx) CG configuration and a reception (Rx) CG configuration. A UE can have both a Tx CG configuration and a Rx CG configuration. As non-limiting examples, a SL CG configuration of a Tx configuration and a Rx configuration can specify resources and other parameters, e.g.: (1) time domain resource configuration parameters, e.g.: time domain allocation periodicity, offset, and size; symbols for PSSCH transmission; bitmap of time locations for each repetition; (2) frequency domain resource configuration parameters, e.g.: subchannel definition: start resource block (RB), end RB, and size of subchannel in terms of RBs; start location and size (in RBs or subchannels) of PSSCH transmission; and frequency hopping information or frequency subchannel index for each repetition; (3) resource pattern or time-frequency resource pattern (TFRP); (4) number of repetitions K (where K specifies the number of times a transmitted TB is repeated); (5) redundancy version (RV) sequence; (6) demodulation reference signal (DMRS) configuration; (7) modulation and coding scheme (MCS) configuration; (8) hybrid automatic repeat request (HARQ) related parameters; (9) power control parameters; (10) destination ID; and (11) source ID. Thus, in example embodiments, a CG configuration can include, among other things, a set of parameters selected from the group consisting of: (1) destination ID of one or more Rx UEs; (2) source ID of a Tx UE; (3) SL time-frequency resources; (4) modulation and coding scheme (MCS) parameters to be used for SL data transmission; and (5) demodulation reference signal (DMRS) parameters. The SL time-frequency resource parameters can specify one or more of the above-described time domain resources and frequency domain resources.

[0044] New Radio (NR) Mode 1 supports two types (Type-1, Type-2) of configured grant (CG) which provide resource configuration for SL transmission in a periodic manner. For Type 1 CG, resource configuration is provided through radio resource control (RRC) signaling. For CG Type 2, resource configuration is provided through a combination of RRC signaling and downlink control information (DCI) signaling. NR Mode 1 will also support dynamic grant which provides resource for one or more SL transmissions of a single TB.

[0045] Reference Figure 1 In the case of NR Mode 1, Type 1, the BS provides SL CG configuration to a UE (e.g., UE1). For example, the BS can send configuration grant information to UE1 indicating SL CG configuration. The configuration grant information is sent to UE1 from the BS (e.g., gNB node) using RRC signaling. The configuration grant information indicates SL CG configuration that UE1 can use for SL communication with one or more other UEs (e.g., UE2). In some cases, the configuration grant information indicates one or more SL CG configurations from a set of candidate SL CG configurations that are pre-configured for the UE. In some examples, the configuration grant information can specify an update to one or more selected parameters of a set of CG configuration parameters. The configuration grant information sent from the BS to UE1 is not dynamic; therefore, the SL CG configuration provided to UE1 is semi-static (e.g., the BS does not provide a new SL GL configuration to the UE for each data transmission; the SL GL configuration is provided for a duration that can cover multiple discontinuous SL data transmissions), and the SL resources for UE1 (e.g., resource parameters specified in the SL resource configuration) are semi-statically configured (e.g., the SL resources are not changed for each data transmission; the configured SL resources can cover multiple SL data transmissions). The BS does not have dynamic DCI signaling to update or change the CG configuration specified in the CG information sent using RRC signaling over a period of multiple SL data transmissions.

[0046] Upon receiving the SL CG configuration from the BS, UE1 can transmit SL data transmissions to other UEs (e.g., UE2) using the transmission resources and other parameters corresponding to the SL CG configuration indicated in the CG transmissions. The SL data transmissions can take the form of transport blocks (TBs) transmitted over a SL data channel (e.g., physical sidelink shared channel (PSSCH)) using the transmission resources specified by the SL CG configuration. In some proposed or existing V2X SL scenarios, each TB is accompanied by sidelink control information (SCI) transmitted over a control channel (physical sidelink control channel (PSCCH)). In cases where a TB has associated SCI, information about the SL CG configuration used for the TB is specified in the SCI, so that a receiving UE (e.g., UE2) can determine the SL CG configuration (or selected parameters of the SL CG configuration) by decoding the SCI.

[0047] In some proposed or existing V2X SL scenarios, a UE (e.g., UE1) can transmit TBs over a SL data channel without accompanying control channel SCI. In such scenarios, the receiving UE uses other methods to identify the SL CG configuration, such as a demodulation reference signal (DMRS) transmitted in association with each TB transmission in the SL data channel.

[0048] As noted above, the CG configuration used by a UE can be semi-persistent, such that the UE can use the same transmission resources and other communication parameters for multiple SL TB transmissions over a period of time. The present disclosure describes methods and systems that take advantage of the semi-persistent or semi-static nature of the CG configuration to reduce system overhead and improve communication and UE efficiency. In particular, example embodiments are directed to transmitting data in a SL data channel without accompanying CG configuration information, in cases where the Rx UE can rely on a previously known CG configuration. In example embodiments, at least some of the SL TB transmissions in the SL data channel are transmitted without accompanying transmissions in the SL control channel that indicate CG configuration parameters.

[0049] In this regard, example embodiments aim to reduce signaling about the CG configuration by relying on semi-static configuration information, thereby avoiding dynamic signaling. In some cases, this can reduce physical layer control channel signaling overhead.

[0050] In case of NR V2X applied to vehicle UEs, UEs frequently move, often at different speeds, and the vicinity of a given UE can change rapidly, thus requiring fast adaptation of CG configuration parameters for SL communication between UEs. Exemplary embodiments relate to adapting and / or updating these CG configuration parameters in a dynamic manner and signaling the adapted and / or updated parameters to Rx UEs in case the configured grant scheme relies on Tx and / or Rx UE pre-configuration and not necessarily on transmission SCI per transport block (TB).

[0051] In exemplary embodiments, the SCI can trigger the parameter adaptation when needed, but the adaptation continues without the SCI accompanying each TB transmission. The CG configuration parameters used by the UE can be configured by RRC signaling or by pre-configuration in the UE, but there can be a one-shot SCI transmitted to inform the Rx UE of the change in CG configuration parameter values, after which the Rx UE takes the updated parameter values for the subsequently received TBs.

[0052] According to some embodiments, the Rx UE keeps the same updated CG configuration after receiving the one-shot SCI unless or until the Rx UE receives another one-shot update SCI.

[0053] In another embodiment, the Rx UE receives the SCI associated with a data transmission indicating an updated CG configuration for that particular data transmission. The Rx UE only uses the updated CG configuration for the one-shot data transmission associated with the one-shot SCI (or in some examples, for a defined time period immediately following the reception of the updated CG configuration SCI), and then reverts to using the CG configuration applied prior to the updated CG configuration.

[0054] Exemplary embodiments are described for the three types of SL transmissions, namely unicast, groupcast, and broadcast. Unicast refers to communication between a single Tx UE and a single Rx UE. Groupcast refers to a single Tx UE transmitting a SL transmission to a group of Rx UEs, where the Rx group membership can be known in advance. Broadcast refers to a Tx UE broadcasting a SL transmission such that all Rx UEs within the Tx UE reception range that satisfy certain criteria are able to successfully decode the data. In some examples, unicast and groupcast transmissions can support HARQ feedback, but broadcast transmissions do not.

[0055] Exemplary embodiments of the systems and methods described below relate to CG resource allocation for NR V2X that does not rely on SCI accompanying each TB transmission to the Rx UE. In this regard, at least some SL data transmissions are performed without an associated transmission indicating SL resources for the SL data transmission. Thus, in exemplary embodiments, a Tx UE and a Rx UE are each semi-persistently provided with a CG configuration that can be used for multiple SL data transmissions, such that the CG configuration indication does not have to be transmitted in association with each individual data transmission (e.g., SCI or otherwise) for the duration of the CG configuration application. A number of exemplary embodiments are described next.

[0056] (1) Tx UE sends one-shot SCI to inform Rx UE about the change of CG configuration

[0057] In a first exemplary embodiment, a BS provides a first CG configuration to a Tx UE (e.g., UE1), and the Tx UE indicates the first CG configuration to a Rx UE (e.g., UE2) using SCI on a SL control channel, as described above with respect to Figure 1 . The first CG configuration SCI can be transmitted in association with a SL data transmission. Subsequently, the Tx UE can transmit SL data transmissions (e.g., multiple different TB transmissions) to the Rx UE using the first CG configuration without transmitting any accompanying signaling to the Rx UE regarding the CG configuration. The Rx UE receives and decodes any received SL data transmissions using the first CG configuration. The Tx UE then detects an event that requires a change to one or more parameters of the CG configuration. Thereafter, the Tx UE selects an updated CG configuration (e.g., that can include one or more updated resources or other parameters in addition to the existing CG configuration) and applies the updated CG configuration parameters to the next data transmission transmitted to the Rx UE. In association with the data transmission using the updated parameters, the Tx UE also transmits SCI specifying the updated CG configuration to the Rx UE over the SL control channel. The Rx UE decodes the SCI and receives and decodes the data transmission using the updated CG configuration.

[0058] Thus, in this first exemplary embodiment, the SCI indicating the CG configuration is only transmitted when a CG configuration update is required. In some examples, the updated CB configuration parameters can be one or more of the CB configuration parameters identified above.

[0059] In some examples, an event that can cause the Tx UE to determine that a parameter update is needed can be the Tx UE determining that the SL channel conditions have changed. For example, the Tx UE can detect a change in channel reliability from NACK or ACK feedback and select one or more different parameters to adjust to accommodate the change. Or, the Tx UE can detect a change in channel conditions from sensed data channel parameters, such as received signal strength indicator (RSSI) or reference signal received power (RSRP) measurements. For example, a change in channel reliability or channel conditions can be caused by a change in relative UE speed and inter-UE distance, among other examples. In some examples, an event that can cause the Tx UE to determine that a parameter update is needed can be signaling of a new CG configuration from the BS.

[0060] This first example embodiment can be applied in both NR V2X Mode 1 and Mode 2, but it can be most applicable in scenarios where the Tx UE can autonomously select from a pool or set of CG configuration parameters dynamically, as with NR V2X Mode 2. Thus, in some examples where this first example embodiment is applied in the context of NR V2X Mode 1, the CG configuration provided by the BS can include a set of CG configuration parameters from which the Tx UE can select.

[0061] In one example application case, UE1 can have been previously configured with a CG configuration provided by the BS. UE1 leaves the DL coverage of the BS but is within the SL coverage of UE2. UE2 can send a CG configuration update to UE1 through SCI. In another example, both the Tx UE and the Rx UE can initially receive a CG configuration from the BS. However, the BS can only update the CG configuration of the Tx UE. The Tx UE then sends a one-shot configuration SCI to the Rx UE to update the CG configuration.

[0062] Updating the CG configuration through one-shot SCI can enable the Rx UE to obtain the resources and parameters for receiving and decoding SL transmissions sent using the CG configuration. In such cases, the data transmissions would not need an associated SCI to dynamically indicate all the corresponding resource parameters for each SL transmission.

[0063] In some examples, the Tx UE can periodically send the CG configuration to the Rx UE using SCI.

[0064] In example embodiments, the Tx UE can send the updated or periodic CG configuration to a single Rx UE in a unicast case, to a defined group in a groupcast case, or to appropriately configured Rx UEs within SL range in a broadcast case.

[0065] (2) BS provides CG configuration for Tx UE and Rx UE

[0066] Reference Figure 2 In a second example embodiment, a BS (e.g., a gNB node) can semi-statically provide a CG configuration to both a Tx UE (e.g., UE1) and one or more Rx UEs (e.g., UE2) using DL signaling. The Tx UE and the one or more Rx UEs can then use the designated CG configuration to transmit and receive SL data transmissions, respectively. In an example embodiment, the same CG configuration is used until the BS provides an updated CG configuration.

[0067] In one example, the BS can use separate DL signaling to indicate a Tx CG configuration to the Tx UE and to indicate an Rx CG configuration to the one or more Rx UEs. In the case that a UE is configured as both a Tx UE and a Rx UE, both the Tx CG configuration and the Rx CG configuration can be transmitted to the UE. Most of the parameters in the Tx CG configuration and the Rx CG configuration can be the same, but certain parameters can be different. For example, the Rx CG configuration can specify a source ID that identifies the Tx UE. The Tx CG configuration can specify a single destination ID that identifies a single Rx UE in the case of unicast, a target group destination ID (e.g., an ID that identifies a target group of Rx UEs) in the case of SL groupcast, or a broadcast destination ID in the case of SL broadcast.

[0068] In the case of NR V2X Mode 1 Type 1, RRC signaling can be used to indicate the Tx CG configuration to the Tx UE and the Rx CG configuration to the one or more Rx UEs. In the case of NR V2X Mode 1 Type 2, both RRC and DCI signaling can be used to indicate the CG configuration.

[0069] In another example, the same CG configuration can be transmitted to the Tx UE and the one or more Rx UEs through a single broadcast or groupcast signaling, such as a group RRC for Type 1 CG or a group common DCI for Type 2 CG. Along with the CG configuration, a destination ID and a source ID can optionally be included in the configuration signaling for SL transmissions.

[0070] (3) PC5 RRC provides CG configuration

[0071] Reference Figure 3In a third example embodiment, the BS indicates the CG configuration (or set of CG configurations) to the Tx UE (e.g., UE1) using DL RRC signaling. The CG configuration is indicated by the BS semi-statically and can include, among other resources and transmission parameters, a destination ID of one or more target Rx UEs (e.g., UE2). In the case of unicast, the destination ID can be a single target Rx UE ID for reception. In the case of groupcast, the destination ID can be an ID of a group of target Rx UEs. For broadcast, the destination ID can be for all potential Rx UEs.

[0072] The Tx UE then indicates the CG configuration to the one or more Rx UEs using PC5 RRC signaling. As known in the art, PC5 RRC is a kind of UE-to-UE higher layer control signaling that is transmitted by the Tx UE to the Rx UE over a physical sidelink data channel (e.g., physical sidelink shared channel (PSSCH)) rather than a physical sidelink control channel (e.g., physical sidelink control channel (PSCCH)). The PC5 RRC signaling is similar to the DL RRC signaling, except that the PC5 RRC signaling is signaled in a SL channel rather than a DL channel.

[0073] The CG configuration indicated using the PC5 RRC signaling can also include, among other resources and transmission parameters, a source ID of the Tx UE. The Rx UE(s) that receive the indication of the CG configuration will then apply the CG configuration in a semi-persistent manner for future data transmissions from the Tx UE over the SL data channel until the Rx UE(s) receive a subsequent PC5 RRC signal indicating an updated CG configuration.

[0074] In this example embodiment, at least the Tx UE is within the coverage of the BS since the Tx UE is receiving the DL RRC signaling indicating the CG configuration. The Rx UE (or Rx UEs) can or can not be within the BS DL coverage, but it (they) is (are) at least within the SL communication range of the Tx UE. This example embodiment is therefore applicable at least to NR N2X Mode 1 SL CG. In some scenarios, SL CG configuration according to this example embodiment can also be considered for NR N2X Mode 2 SL transmissions since the SL CG configuration can be used when one or more Rx UEs are not within the BS coverage.

[0075] (4) pre-configuration

[0076] Reference Figure 4Another example embodiment applies to the case when the UE is not in the BS DL coverage. In this regard, in example embodiments, a Tx UE (e.g., UE1) is pre-configured with a set or pool of candidate CG configurations. The Tx UE can be pre-configured with the CG configuration pool in a variety of different ways. For example, the Tx UE can be pre-configured with the CG configuration pool by DL RRC signaling from the BS before the Tx UE leaves the BS DL coverage, or by system information block (SIB).

[0077] The Tx UE selects a CG configuration from the CG configuration pool and indicates the CG configuration to one or more Rx UEs (e.g., UE2). For example, the CG configuration can be indicated using PC5 RRC signaling, or in alternative examples using SCI.

[0078] The Rx UE(s) that receive the CG configuration indication will then apply the CG configuration in a semi-persistent manner for future data transmissions from the Tx UE over the SL data channel until the Rx UE(s) receive a subsequent SL signal indicating an updated CG configuration.

[0079] In this regard, in example embodiments, the Tx UE can select an initial CG configuration from its pre-configured CG configuration pool according to the sensed SL channel conditions. The Tx UE indicates the CG configuration to the Rx UE (using PC5 RRC signaling, or in alternative examples using SCI) and applies the CG configuration for SL data communications until the Tx UE detects an event that requires a change in the CG configuration (e.g., when the Tx UE senses channel conditions that require a change). Thereafter, the Tx UE selects an updated CG configuration (e.g., which can include one or more updated resources or other parameters in addition to the existing CG configuration) and applies the updated CG configuration for the next data transmission to the Rx UE. Prior to or with the data transmission using the one or more updated parameters, the Tx UE also transmits an updated CG configuration indication to the Rx UE specifying the updated CG configuration. The Rx UE then updates the CG configuration to receive and decode the data transmission and future transmissions until it receives yet another CG configuration update indication from the Tx UE. In some examples, the Rx UE only applies the updated CG configuration for a pre-configured duration (e.g., until a pre-configured timer triggered by the configuration SCI expires).

[0080] In some examples, the sensing by the TX UE can be similar to that described above with respect to the first example embodiment.

[0081] In this exemplary embodiment, both Tx UE and Rx UE can not be in the BS DL coverage. Therefore, this embodiment is applicable to the NR V2X SL Mode 2 CG transmission scheme. In some embodiments, the Tx UE can be in the DL coverage without BS instruction in the CG configuration, but autonomously selects the CG configuration grant or configuration grant parameters from its pre-configured CG configuration set or CG configuration parameter set, in which case the above-mentioned embodiment can also be applicable to the NR V2X SL Mode 1 version.

[0082] (5) GF configuration for broadcast

[0083] Although PC5 RRC can be used to broadcast the CG configuration indication from one Tx UE to all other UEs in the SL coverage, it can also be used to groupcast from one Tx UE to other UEs in a group of UEs, but in some cases it can not be feasible to provide CG configuration through PC5 RRC.

[0084] Therefore, in one exemplary embodiment, a grant-free (GF) configuration for broadcast can be indicated by the Tx UE through transmitting a periodic SCI containing CG configuration details carried in PSCCH. The CG configuration SCI can be a one-shot SCI. However, since the proximity of the Tx UE can change over time due to, for example, UE mobility, using periodic SCI to transmit CG configuration can be used to ensure that all Rx UEs in the proximity of the Tx UE are able to receive the CG sidelink transmission.

[0085] Another method of transmitting CG configuration for broadcast traffic in sidelink is through the physical layer broadcast channel (PSBCH). The PSBCH signaling periodically transmitted by the Tx UE can contain the CG configuration information required to configure the Rx UEs. A certain number of bits in the PSBCH transmission can be dedicated to transmitting CG configuration details.

[0086] (6) Tx UE sends information about CG configuration parameters or update of CG configuration parameters to Rx UE through data channel signaling without using SCI.

[0087] In another exemplary embodiment without using SCI signaling, the Tx UE sends information about the selected CG configuration parameters (e.g., source ID and destination ID) to the Rx UE by transmitting or embedding signaling in the data channel in the SL data channel (e.g., PSSCH) to inform one or more RX UEs of the change in selected parameters.

[0088] In unicast case, the destination ID can be the Rx UE ID for reception. In groupcast case, the destination ID can be the ID of the target group of receiving UEs. For broadcast, the destination ID can be for all potential Rx UEs.

[0089] In example embodiments, the source ID and destination ID are generated at the Tx UE and thus not included in the CG configuration provided by the BS. The source ID / destination ID need to be indicated by the Tx UE to the Rx UE. In typical grant-based scheme, such indication is carried in SCI, which is conveyed by PSCCH associated with the PSSCH carrying the data. In case of CG scheme, there is a possibility that no SCI is transmitted, i.e., the data transmission (e.g., TB) is transmitted in a standalone PSSCH independent of any PSCCH.

[0090] In example embodiments, in the absence of PSCCH SCI, the Tx UE can need to inform one or more Rx UEs of one or both of the source ID and destination ID. In this regard, there are two possible options to inform the one or more Rx UEs of the source ID / destination ID or any other configuration parameters carried in PSCCH in grant-based scheme are:

[0091] 1. Option 1: Attach / append a sidelink medium access control-control element (MAC-CE) including the source ID and / or destination ID on the data before the actual PSSCH data transmission on the CG resource allocated for data transmission through PC5 RRC signaling, such that the MAC-CE is jointly encoded with the payload data included in the PSSCH data transmission.

[0092] 2. Option 2: The source ID and / or destination ID are transmitted separately on a specific resource within the entire resource configured through PC5 RRC signaling and the source ID / destination ID including the payload data are included in the PSSCH data transmission, even if both are transmitted using semi-statically configured CG resource or resource of semi-persistent scheduling (SPS).

[0093] Thus, in one example embodiment without using SCI signaling, the Tx UE sends information to the Rx UE about the selected CG configuration parameters (e.g., source ID and destination ID) through signaling transmitted in the data channel to inform the one or more RX UEs of the selected parameters or update of the selected parameters.

[0094] Apparatus Description

[0095] Figure 5FIG. 1 is a block diagram of an example of a telecommunications network 1400 for implementing any one or a combination of the two or more methods described above, according to an embodiment. The telecommunications network 1400 includes a core network 1402 and an access network 1406. The access network 1406 serves a plurality of UEs 1404a, 1404b, 1404c, 1404d, 1404e, 1404f, 1404g, 1404h, and 1404i (which can include UE1 and UE2). The access network 1406 can be an Evolved Universal Terrestrial Access (E-UTRA) network. As another example, the access network 1406 can be a Cloud-RAN (C-RAN). The access network 1406 includes a plurality of BSs 1408a, 1408b, and 1408c. The BSs 1408a-c provide respective wireless coverage areas 1410a, 1410b, and 1410c, respectively. The BSs 1408a-c can each be implemented using a wireless transceiver, one or more antennas, and associated processing circuitry (e.g., antenna radio frequency (RF) circuitry, analog / digital converters, etc.).

[0096] Although not shown, the BSs 1408a-c are connected to the core network 1402, either directly or through one or more central processing hubs (e.g., servers). The BSs 1408a-c can act as gateways between the wired and wireless portions of the access network 1406.

[0097] Depending on the implementation, the BSs 1408a-c can also be referred to as base transceiver stations, wireless BSs, network nodes, transmission nodes, transmission points, Node Bs, eNode Bs, or remote radio heads (RRHs), respectively.

[0098] In operation, the plurality of UEs 1404a-i access the telecommunications network 1400 using the access network 1406 through wireless communication with one or more of the BSs 1408a-c.

[0099] The UEs 1404a-d are in close proximity to each other. The UEs 1404a-d can each be in wireless communication with the BS 1408a. The UEs 1404a-d can also communicate directly with each other, as indicated by 1416. The communication represented by 1416 is direct communication between the UEs without going through an access network component (e.g., a BS). As such, the UEs 1404a-d can communicate directly with each other using a sidelink (SL) interface. Figure 2As shown, inter-UE communications 1416 occur directly between UEs 1404a-d and are not routed through BS 1408a or any other portion of access network 1406. Communications 1416 can also be referred to as sidelink or SL communications. In embodiments disclosed herein, inter-UE communications 1416 use an SL channel and an SL air interface, e.g., including an SL PC5 interface. On the other hand, communications between an access network component (e.g., BS 1408a) and a UE (e.g., communications 1414) are referred to as access communications. Access communications occur on an access channel, which can be a UL or DL channel, and use a wireless access communication interface, e.g., a cellular wireless access air interface. The access and SL air interfaces can use different transmission formats, e.g., different waveforms, different multiple access schemes, and / or different radio access technologies. Some examples of radio access technologies that the access air interface and / or the SL air interface can use are: long term evolution (LTE), LTE license assisted access (LTE-LAA), 5G new radio, and WiFi.

[0100] By using SL communications 1416, UEs 1404a-d are able to assist in wireless communications between UEs 1404a-d and BS 1408a. For example, if UE 1404c fails to correctly decode a data packet received from BS 1408a, but UE 1404d is able to receive and correctly decode the data packet from BS 1408a, then UE 1404d can send the decoded data packet directly to UE 1404c over SL communications 1416. As another example, if UE 1404c moves out of wireless coverage area 1410c such that UE 1404c can no longer wirelessly communicate with BS 1408a, then UE 1404b can relay messages between UE 1404c and BS 1408a. As another example, UEs 1404a and 1404c can both receive a signal transmitted from BS 1408a that carries a data packet for UE 1404c. UE 1404a can then send the signal received by UE 1404a to UE 1404c over SL communications 1416. UE 1404c can then use the information received from UE 1404a to help decode the data packet from BS 1408a. In these examples, capacity and / or coverage can be enhanced by the assistance of UEs 1404a, 1404b, and / or 1404d. V2X communications referenced herein are an example of SL communications.

[0101] The UEs 1404a-d form a UE group 1420. The access network 1406 can assign a group identification (ID) to the UE group 1420. The UE group ID can support the access network 1406 addressing the UE group 1420 as a whole and distinguishing the UE group 1420 from other UE groups. The UE group ID can also be used to broadcast information within the UE group, i.e., addressing all other UEs within the UE group 1420. The UE group 1420 can form a logical or virtual device grid, where members of the UE group 1420 communicate among themselves using UE communications over the SL air interface. The UE group 1420 as a whole can act as a single distributed virtual transceiver with respect to the access network 1406. For example, the UE group ID can be a group radio network temporary identifier (G-RNTI).

[0102] When a particular UE in the UE group 1420 is being assisted or will be assisted in wireless communications between the UE and the BS 1408a, then the particular UE is referred to as a target UE (TUE). In the above example, the UE 1404c is being assisted and thus is a TUE. The other UEs 1404a, 1404b, and 1404d in the group 1420 form a set of cooperation candidates, which is a set of UEs that can cooperate to help the TUE 1404c. A subset of UEs in the set of cooperation candidates that actually assist the target UE 1404c form a set of cooperation activators. The set of cooperation activators can be selected dynamically to assist the target UE 1404c. The UEs in the set of cooperation activators are referred to as cooperating UEs (CUEs). In the UE group 1420, the UEs 1404a, 1404b, and 1404d form a set of cooperation candidates. If the UEs 1404a and 1404b actually assist the target UE 1404c, then the UEs 1404a and 1404b form a set of cooperation activators and are CUEs. As the UEs 1404a-d move around, some UEs can leave the UE group 1420 and / or other UEs can join the UE group 1420. Thus, the set of cooperation candidates can change over time, e.g., the set of cooperation candidates can change semi-statically. The UE group 1420 can also be terminated by the network 1406 if the network determines that the UE group 1420 is no longer needed or no longer has an opportunity to assist in wireless communications between the BS 908a and members of the UE group 1420, in the above example implementation. In the above example implementation, UE1 and UE2 are part of a UE group.

[0103] There can be more than one UE group. For example, Figure 5 The UEs 1404e and 1404f in form another UE group 1422.

[0104] Figure 6 is a block diagram of an example of a network 1552 serving two UEs 1554a and 1554b, according to an embodiment. The network 1552 can beFigure 5 Access network 1406 in FIG. 13, two UEs 1554a and 1554b can be Figure 5 two of the four UEs 1404a-d in FIG. 13, and can be used to implement UE1 and UE2 described above, for example. More generally, however, this need not be the case, and thus different reference numbers are used in Figure 6 FIG. 13.

[0105] Network 1552 includes BS 1556 and a management module 1558. Management module 1558 instructs BS 856 to perform actions. Management module 858 is shown as being physically separate from BS 1556 and is coupled to BS 1556 by a communication link 1560. For example, management module 1558 can be part of a server in network 1552. Alternatively, management module 1558 can be part of BS 1556.

[0106] Management module 1558 includes a processor 1562, a memory 1564, and a communication module 1566. Communication module 1566 is implemented by processor 1562 when processor 1562 accesses and executes a series of instructions stored in memory 1564, which define the actions of communication module 1566. When the instructions are executed, communication module 1566 causes BS 1556 to perform the actions described herein, such that network 1552 can establish, coordinate, instruct, and / or control groups of UEs. Alternatively, communication module 1566 can be implemented using special-purpose circuitry, such as an application-specific integrated circuit (ASIC) or a programmed field-programmable gate array (FPGA).

[0107] UE 1554a includes a communication subsystem 1570a, two antennas 1572a and 1574a, a processor 1576a, and a memory 1578a. UE 1554a also includes a communication module 1580a. Communication module 1580a is implemented by processor 1576a when processor 1576a accesses and executes a series of instructions stored in memory 1578a, which define the actions of communication module 1580a. When the instructions are executed, communication module 1580a causes UE 1554a to perform the actions described herein with respect to establishing and participating in groups of UEs. Alternatively, module 1580a can be implemented by special-purpose circuitry, such as an ASIC or a FPGA.

[0108] The communication subsystem 1570a includes processing and transceiving circuitry for transmitting messages from and receiving messages at the UE 1554a. While one communication subsystem 1570a is shown, the communication subsystem 1570a can be multiple communication subsystems. The antenna 1572a transmits wireless communication signals to the BS 1556 and receives wireless communication signals from the BS 1556. The antenna 1574a transmits SL communication signals to and receives SL communication signals from other UEs, including the UE 1554b. In some implementations, there can not be two separate antennas 1572a and 1574a. A single antenna can be used. Alternatively, there can be multiple antennas, but not separated into antennas for SL communication only and antennas for communicating with the BS 1556 only.

[0109] The SL communication can be over Wi-Fi, in which case the antenna 1574a can be a Wi-Fi antenna. Alternatively, the SL communication can be over Bluetooth TM , in which case the antenna 1574a can be a Bluetooth TM antenna. The SL communication can also or instead be over licensed or unlicensed spectrum.

[0110] The UE 1554b includes the same components as described above with respect to the UE 1554a. That is, the UE 1554b includes a communication subsystem 1570b, antennas 1572b and 1574b, a processor 1576b, a memory 1578b, and a communication module 1580b.

[0111] The UE 1554a is designated as a target UE (TUE), and is therefore referred to as the TUE 1554a. The UE 1554b is a cooperating UE, and is therefore referred to as the CUE 254b. If a group of UEs including the TUE 1554a and the CUE 1554b is to be established, the CUE 1554b can assist in wireless communication between the BS 1556 and the TUE 1554a. Other communication scenarios can also be considered, such as in V2X applications.

[0112] The UE 1554a can be specifically selected by the network 1552 to be a target UE. Alternatively, the UE 1554a can determine that it wishes to be a target UE, and inform the network 1552 by sending a message to the BS 1556. Exemplary reasons for the UE 1554a to select or be selected by the network 1552 to be a target UE include: a low quality of a wireless channel between the UE 1554a and the BS 1556, many data packets to be communicated between the BS 1556 and the UE 1554a, and / or a presence of a cooperating UE that is a good candidate to help in communication between the BS 1556 and the UE 1554a.

[0113] UE 1554a need not always remain a target UE. For example, UE 1554a can lose its status as a target UE once it is no longer needed or desired to assist in wireless communication between UE 1554a and BS 1556. UE 1554a can later assist another target UE as a cooperating UE. In general, a particular UE can be a target UE at times and a cooperating UE assisting another target UE at other times. Moreover, a particular UE can be both a target UE receiving assistance from one or more cooperating UEs and a cooperating UE assisting another target UE at times. In the example below, UE 1554a is a target UE only, TUE 1554a, and UE 1554b is a cooperating UE for TUE 1554a, CUE 1554b.

[0114] Figure 5 and Figure 6 A system in which embodiments can be implemented is shown. In some embodiments, a UE includes a processor (e.g., 1576a, 1576b in FIG. 15) and a non-transitory computer-readable storage medium (e.g., 1578a, 1578b in FIG. 15) storing programming for execution by the processor. Figure 6 In addition or alternatively, the non-transitory computer-readable storage medium is provided as a computer program product separate from the processor. Figure 6

[0115] Figure 7 is a flowchart of a process that can be performed by a Tx UE (e.g., UE1) for wireless SL communication in accordance with one or more embodiments described above. As shown in block 702, the Tx UE transmits a first SL signal to a receiving (Rx) UE (e.g., UE2), the first SL signal indicating parameters of a configured grant (CG) configuration. As shown in block 704, the Tx UE then transmits a plurality of SL data transmissions to the Rx UE in a sidelink data channel in accordance with the indicated parameters, wherein at least one of the SL data transmissions is transmitted without an accompanying transmission in a SL control channel indicating the parameters.

[0116] In at least some examples, the first SL signal includes sidelink control information (SCI) and is transmitted in a SL control channel.

[0117] As shown in block 706, in some examples, the Tx UE can select updated CG configuration parameters and transmit a second SL signal to the receiving (Rx) UE, the second SL signal including SCI indicating the updated CG configuration parameters. In some examples, the Tx UE can be triggered to select updated CG configuration in accordance with a change in SL data channel properties. In this regard, the Tx UE can sense SL channel information and select appropriate updated CG configuration parameters. ​

[0118] As represented by block 708, in some examples, the Tx UE can then transmit a plurality of SL data transmissions to the Rx UE in accordance with the updated CG configuration parameters, where at least one of the SL data transmissions is transmitted without an accompanying transmission indicating the updated CG configuration parameters. In at least some examples, the updated CG configuration parameters update only a subset of the parameters indicated in the first signal.

[0119] As indicated above at least with respect to Figure 1 , Figure 2 and Figure 4 , in some examples, the Tx UE can receive signaling from a base station (BS) indicating a CG configuration prior to transmitting the first signal.

[0120] As indicated above at least with respect to Figure 3 and Figure 4 , in some examples, the first SL signal is transmitted using radio resource control (RRC) signaling in a SL data channel. In some examples, the first SL signal is transmitted using a physical layer broadcast channel (PSBCH).

[0121] In at least some example embodiments, the CG configuration relates to a broadcast grant-free (GF) configuration of a plurality of Rx UEs, where the first signal is transmitted to the plurality of Rx UEs, and: (i) the first SL signal includes sidelink control information (SCI) transmitted in a SL control channel; or (ii) the first SL signal is transmitted using a PSBCH transmission. The Tx UE can transmit a second SL signal indicating the updated CG configuration parameters to the plurality of Rx UEs in a SL data channel.

[0122] In at least some example embodiments, the CG configuration includes a set of parameters selected from a group consisting of: (1) a destination ID of one or more Rx UEs; (2) a source ID of the Tx UE; (3) a SL data channel time-frequency resource; (4) a modulation and coding scheme (MCS) parameter to be used for the SL data transmissions; and (5) a demodulation reference signal (DMRS) parameter.

[0123] In some examples, the Tx UE transmits an indication of one or both of a source ID of the Tx UE or a destination ID of the Rx UE in the SL data channel. In some example embodiments, the Tx UE transmits the indication of one or both of the source ID and the destination ID by encoding a medium access control-control element (MAC-CE) indicating one or both of the source ID and the destination ID, and jointly encoding the MAC-CE with payload data in one of the multiple data transmissions. In some alternative examples, the Tx UE transmits the indication of one or both of the source ID and the destination ID by transmitting the indication using SL data channel time-frequency resources that are not used for any of the multiple data transmissions.

[0124] In some examples, the method includes periodically transmitting an SCI SL signal to the Rx UE to update parameters of a configured grant (CG) configuration applied by the Rx UE.

[0125] In the above non-broadcast examples, the Tx UE can perform the operations for a single Rx UE (unicast) or multiple Rx UEs (groupcast), with each Rx UE provided with a respective CG configuration to semi-persistently apply to a group of SL data transmissions.

[0126] Figure 8 is a flowchart of a process for a Rx UE for wireless SL communication provided by example embodiments. As shown in block 802, the Rx UE determines a configured grant (CG) configuration for processing SL data transmissions received by the Rx UE. As shown in block 804, the Rx UE then receives and processes multiple discontinuous SL data transmissions using the CG configuration. In some example embodiments, the Rx UE determines the CG configuration by receiving, over a SL control channel, a sidelink control information (SCI) indicating the CG configuration, and at least one of the multiple discontinuous SL data transmissions is received over a SL data channel without an accompanying SCI indicating the CG configuration.

[0127] In Figure 7 and Figure 8 In examples of the above, the Tx UE and the Rx UE are semi-statically provided with the CG configuration, respectively, such that the CG configuration indicates not necessarily transmitted in association with each individual data transmission for a duration of application of the CG configuration.

[0128] Many modifications and variations of the present application can be made in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the application can be practiced otherwise than as specifically described.

Claims

1. A method performed at a transmitting (Tx) user equipment (UE) for wireless sidelink (SL) communication, the method comprising: The method comprises: receiving signaling for a pool of preconfigured CG configurations before the Tx UE leaves a base station downlink coverage; selecting a CG configuration from the pool of CG configurations according to sensed SL channel conditions; transmitting a first SL signal to a receiving (Rx) UE, the first SL signal indicating parameters of a configured grant (CG) configuration; transmitting a plurality of SL data transmissions to the Rx UE in a SL data channel according to the parameters, wherein at least one of the SL data transmissions is transmitted without an accompanying transmission in a SL control channel indicating the parameters, the Tx UE and the Rx UE semi-statically using the CG configuration, the CG configuration indicating no transmission necessarily associated with each individual data transmission for a duration of application of the CG configuration; determining, at the Tx UE, that SL channel conditions have changed, selecting an updated CG configuration from the pool of CG configurations, transmitting a second SL signal to the Rx UE, the second SL signal indicating updated CG configuration parameters.

2. The method of claim 1, wherein, The first SL signal comprises sidelink control information (SCI) and is transmitted in the SL control channel.

3. The method of claim 2, wherein The second SL signal comprises SCI in the SL control channel indicating the updated CG configuration parameters.

4. The method of claim 3, wherein, comprises: transmitting a plurality of further SL data transmissions to the Rx UE in the SL data channel according to the updated CG configuration parameters, wherein at least one of the plurality of further SL data transmissions is transmitted without an accompanying transmission indicating the updated CG configuration parameters.

5. The method of claim 4, wherein, The updated CG configuration parameters update only a subset of the parameters indicated in the first SL signal.

6. The method according to any one of claims 1 to 5, characterized in that, comprises: transmitting an indication of one or both of a source ID of the Tx UE or a destination ID of the Rx UE in the SL data channel.

7. The method of claim 6, wherein, Transmitting the indication of one or both of the source ID and the destination ID comprises encoding a medium access control-control element (MAC-CE) indicating one or both of the source ID and the destination ID and jointly encoding the MAC-CE with payload data in one of the plurality of SL data transmissions.

8. The method of claim 6, wherein, Transmitting the indication of one or both of the source ID and the destination ID comprises transmitting the indication using SL data channel time-frequency resources not used for any of the plurality of SL data transmissions.

9. The method according to any one of claims 1 to 8, characterized in that, The first SL signal is transmitted using radio resource control (RRC) signaling in the SL data channel.

10. The method according to any one of claims 1 to 8, characterized in that, The first SL signal is transmitted in a physical layer broadcast channel (PSBCH).

11. The method according to any one of claims 1 to 10, characterized in that, The CG configuration relates to a broadcast grant-free (GF) configuration of a plurality of Rx UEs, wherein the first SL signal is transmitted to a plurality of Rx UEs, and: (i) the first SL signal comprises sidelink control information (SCI) and is transmitted in the SL control channel; or (ii) the first SL signal is transmitted using PSBCH transmission, the method further comprising transmitting a second SL signal to the plurality of Rx UEs in a SL data channel transmission, the second SL signal indicating updated CG configuration parameters.

12. The method according to any one of claims 1 to 11, characterized in that, The CG configuration includes a set of parameters selected from the group consisting of: (1) a destination ID of one or more Rx UEs; (2) a source ID of the Tx UE; (3) SL data channel time-frequency resources; (4) a modulation and coding scheme (MCS) parameter to be used for SL data transmissions; and (5) a demodulation reference signal (DMRS) parameter.

13. The method according to any one of claims 1 to 12, characterized in that, The Tx UE semi-statically applies the CG configuration such that the parameters are not necessarily transmitted from the Tx UE to the Rx UEs in association with each individual SL data transmission for a duration of application of the CG configuration.

14. The method according to any one of claims 1 to 13, characterized in that, including periodically transmitting an SCI SL signal to the Rx UEs to update parameters of a configured grant (CG) configuration applied by the Rx UEs.

15. A transmitting (Tx) user equipment (UE) configured to: A transmitting (Tx) user equipment (UE) for wireless sidelink (SL) communication with one or more receiving (Rx) UEs, the Tx UE configured to: receive signaling for a pool of preconfigured CG configurations before the Tx UE leaves a base station downlink coverage; select a CG configuration from the pool of CG configurations according to a sensed SL channel condition; transmit a first SL signal to the Rx UEs, the first SL signal indicating parameters of a configured grant (CG) configuration; transmit a plurality of SL data transmissions to the Rx UEs in a SL data channel according to the parameters, wherein at least one of the SL data transmissions is transmitted without an accompanying transmission in a SL control channel indicating the parameters, the Tx UE and the Rx UEs semi-statically using the CG configuration, the CG configuration indicating that the parameters are not necessarily transmitted in association with each individual data transmission for a duration of application of the CG configuration; determine that SL channel conditions have changed, select an updated CG configuration from the pool of CG configurations, transmit a second SL signal to the Rx UEs, the second SL signal indicating updated CG configuration parameters.

16. The Tx UE of claim 15, wherein, The second SL signal includes SCI in the SL control channel indicating the updated CG configuration parameters.

17. The Tx UE of claim 16, wherein, The Tx UE is configured to transmit further SL data transmissions according to the updated CG configuration parameters, wherein at least one of the further SL data transmissions is transmitted without an accompanying transmission in a SL control channel indicating the updated CG configuration parameters.

18. The Tx UE of any one of claims 15-17, wherein, The first SL signal includes sidelink control information (SCI) transmitted in a SL control channel.

19. The Tx UE of any one of claims 15-18, wherein, The Tx UE transmits the first SL signal using radio resource control (RRC) signaling in the SL data channel.

20. The Tx UE of any one of claims 15-18, wherein, The Tx UE transmits the first SL signal using a physical layer broadcast channel (PSBCH).

21. A computer program product, characterised in that, A non-transitory computer medium storing instructions that cause a transmitting (Tx) user equipment (UE) to: receiving signaling for a pool of preconfigured CG configurations before the Tx UE leaves a base station downlink coverage; selecting a CG configuration from the pool of CG configurations according to sensed SL channel conditions; transmitting a first SL signal to a receiving (Rx) UE, the first SL signal indicating parameters of a configured grant (CG) configuration; transmitting a plurality of SL data transmissions to the Rx UE in a SL data channel according to the parameters, wherein at least one of the SL data transmissions is transmitted without an accompanying transmission in a SL control channel indicating the parameters, the Tx UE and the Rx UE semi-statically using the CG configuration, the CG configuration indicating no transmission is necessary in association with each individual data transmission for a duration of application of the CG configuration; determining that SL channel conditions have changed, selecting an updated CG configuration from the pool of CG configurations, and transmitting a second SL signal to the Rx UE, the second SL signal indicating updated CG configuration parameters.

22. A method for receiving data at a receiving (Rx) user equipment (UE) over a sidelink (SL) data channel, characterized in that, comprising: determining a configured grant (CG) configuration for processing SL data transmissions received by the Rx UE, the CG configuration being a CG configuration selected by a Tx UE from a pool of CG configurations according to sensed SL channel conditions, the pool of CG configurations being preconfigured by a base station before the Tx UE leaves a base station downlink coverage; receiving and processing a plurality of discontinuous SL data transmissions using the CG configuration, the Tx UE and the Rx UE semi-statically using the CG configuration, the CG configuration indicating no transmission is necessary in association with each individual data transmission for a duration of application of the CG configuration; receiving a second SL signal indicating updated CG configuration parameters, the second SL signal being transmitted when the Tx UE determines that SL channel conditions have changed, the updated CG configuration being selected from the pool of CG configurations.

23. The method of claim 22, wherein, determining the CG configuration comprises receiving sidelink control information (SCI) indicating the CG configuration over a SL control channel, and at least one of the plurality of discontinuous SL data transmissions is received over a SL data channel without accompanying SCI indicating the CG configuration.

24. A receive (Rx) user equipment (UE) comprising: for receiving wireless sidelink (SL) communications from a transmitting (Tx) UE, the Rx UE to: determine a configured grant (CG) configuration for processing SL data transmissions received by the Rx UE, the CG configuration being a CG configuration selected by a Tx UE from a pool of CG configurations according to sensed SL channel conditions, the pool of CG configurations being preconfigured by a base station before the Tx UE leaves a base station downlink coverage; process a plurality of discontinuous SL data transmissions using the CG configuration, the Tx UE and the Rx UE semi-statically using the CG configuration, the CG configuration indicating no transmission is necessary in association with each individual data transmission for a duration of application of the CG configuration; receive a second SL signal indicating updated CG configuration parameters, the second SL signal being transmitted when the Tx UE determines that the SL channel condition has changed, the updated CG configuration being selected from the CG configuration pool.

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