UU-based lateral link control for NR V2X

Abstract

The invention relates to a UU-based lateral link control for NR V2X. Different lateral link resource configurations and allocation schemes may be controlled through an interface, such as a Uu interface. The radio resource control configuration may include a dynamic assignment of broadcast side link transmissions, unicast side link transmissions, or group side link transmissions. There may be static resource allocation for radio resource control configurations for broadcast side link transmissions, unicast side link transmissions, or group side link transmissions.

Description

[0001] This application is a divisional application of Chinese patent application 201980063416.9, filed on March 26, 2021, with the invention name “UU-based side link control for NR V2X”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 737,257, filed on September 27, 2018, and U.S. Provisional Patent Application No. 62 / 754,326, filed on November 1, 2018, both of which are incorporated herein by reference in their entirety. Background Art

[0004] As vehicle-to-everything (V2X) applications make significant progress, there is a need to extend the sending of short messages for basic safety regarding the vehicle's own state data with the sending of larger messages containing raw sensor data, vehicle intent data, coordination, confirmation of future maneuvers, etc. For these advanced applications, the expected requirements for data rates, latency, reliability, communication range and speed to meet the needs become more stringent.

[0005] For enhanced V2X (eV2X) services, 3GPP has confirmed 25 use cases and related requirements in TR 22.886 (GPP TR 22.886 Study on enhancement of 3GPP Support for 5G V2X Services, Release 15, V15.2.0.).

[0006] A set of standard requirements are specified in TS22.186 (GPP TS22.186 Enhancement of 3GPP support for V2X scenarios (Stage 1), Release 15, V15.3.0), and the use cases are classified into four use case groups: vehicle formation, extended sensors, advanced driving and remote driving. A detailed description of the performance requirements for each use case group specified in TS22.186.

[0007] In Release 14 LTE V2X, basic requirements for V2X services are supported for road safety services, such as supporting low latency and reliable exchange of messages between vehicles and infrastructure to improve safety and efficiency.

[0008] In order to meet the latency requirements and accommodate the high Doppler spread and high density of vehicles for V2X communications, sidelink transmission Mode 3 and Mode 4 have been specified in TS 36.213 (3GPP TS 36.213 Physical layer procedures, Release 15, V15.2.0).

[0009] Mode 3 uses a centralized eNB scheduler. The vehicle user equipment (UE) and the eNB communicate using the Uu interface. The eNB schedules the PSCCH and PSSCH of the vehicle UE for sidelink communication using downlink control information (DCI) format 5A.

[0010] In NR V2X, sidelink resource allocation mode 1 and mode 2 are recognized. In mode 1, the base station schedules the sidelink resources used by the UE for sidelink transmission. In mode 2, the UE determines the sidelink resources used for sidelink transmission within the sidelink resources configured by the base station or the pre-configured sidelink resources.

[0011] Mode 1 supports gNB to allocate sidelink resources for both dedicated sidelink carrier and shared licensed carrier between Uu and sidelink over Uu interface. Resources for sidelink transmission can be allocated dynamically, either pre-configured through RRC, or based on activation and deactivation. Summary of the invention

[0012] Different sidelink resource configuration and allocation schemes that can be controlled through an interface (such as a Uu interface) are disclosed herein. For example, the following mechanisms for resource allocation on the sidelink can be based on Uu: 1) RRC configuration; 2) DCI signaling; 3) scheduling sidelink transmission; 4) design of multicast sidelink; or 5) measurement and reporting on the sidelink.

[0013] The RRC configuration may include: 1) dynamic resource allocation for broadcast, unicast or group side link transmission; 2) RRC configured static resource allocation for broadcast, unicast or group side link transmission; 3) activation / deactivation (e.g., activation or deactivation) based semi-permanent resource allocation for broadcast side link transmission; 4) activation / deactivation based semi-permanent resource allocation for unicast side link transmission; or 5) activation / deactivation based semi-permanent resource allocation for groupcast side link transmission, etc.

[0014] Also disclosed is DCI signaling, which allows the gNB to schedule, for example, sidelink transmissions, the design of multicast sidelinks, and mechanisms for measurement and reporting on sidelinks.

[0015] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description in a simplified form. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Additionally, the claimed subject matter is not limited to limitations that solve any or all disadvantages noted in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A more detailed understanding may be obtained through the following description given as an example in conjunction with the accompanying drawings, in which:

[0017] Figure 1 An exemplary DCI for scheduling PSCCH and PSSCH is shown;

[0018] Figure 2 represents an exemplary time slot format for a sidelink;

[0019] Figure 3 An exemplary call flow showing gNB triggered retransmission for unicast sidelink;

[0020] Figure 4 An exemplary call flow for Rx UE triggered retransmission for unicast sidelink is shown;

[0021] Figure 5 shows an example of a time slot format for a unicast sidelink;

[0022] Figure 6 An exemplary call flow showing gNB triggered retransmission for multicast sidelink;

[0023] Figure 7 An exemplary call flow for Rx UE triggered retransmission for multicast sidelink is shown;

[0024] Figure 8 An exemplary display (e.g., graphical user interface) that can be generated by methods, systems, and apparatus based on mobility signaling load reduction is shown;

[0025] Fig. 9A represents an exemplary communication system;

[0026] Fig. 9B represents an exemplary system including a RAN and a core network;

[0027] Fig. 9C represents an exemplary system including a RAN and a core network;

[0028] Fig.9D represents an exemplary system including a RAN and a core network;

[0029] Fig.9Erepresents another exemplary communication system;

[0030] Fig.9F is a block diagram of an exemplary device or apparatus, such as a WTRU;

[0031] Figure 9G is a block diagram of an exemplary computing system;

[0032] Fig.10 represents an exemplary transmission of scheduling DCI for both Tx UE and Rx UE, HARQ feedback is sent from RxUE to gNB;

[0033] Fig.11 represents an exemplary transmission of scheduling DCI for both Tx UE and Rx UE, HARQ feedback is sent from Rx UE to Tx UE;

[0034] Fig.12 shows an exemplary transmission of scheduling DCI for both Tx UE and Rx UE, HARQ feedback is sent from Rx UE to Tx UE and fed back from Tx UE to gNB;

[0035] Fig.13 represents an exemplary transmission of scheduling DCI for Tx UE, HARQ feedback is sent from Rx UE to gNB;

[0036] Fig.14 represents an exemplary transmission of a scheduling DCI for a Tx UE, and HARQ feedback is sent from the Rx UE to the Tx UE;

[0037] Fig.15A represents an exemplary transmission of scheduling DCI for Tx UE, HARQ feedback is sent from Rx UE to Tx UE and fed back from Tx UE to gNB;

[0038] Fig. 15B An exemplary method for scheduling DCI for a Tx UE is shown, HARQ feedback is sent from the Rx UE to the Tx UE and fed back from the Tx UE to the gNB;

[0039] Fig.16 shows an exemplary transmission of scheduling DCI for both Tx UE and Rx UE using a shared carrier for Uu interface and sidelink;

[0040] Fig.17 represents an exemplary PSCCH-TimeDomainResourceAllocationList information element;

[0041] Fig.18represents an exemplary PSSCH-TimeDomainResourceAllocationList information element;

[0042] Fig.19 represents an exemplary RRC configuration PSFCH-Resource;

[0043] Fig. 20 showing an exemplary DCI dynamically scheduled sidelink transmission with blind retransmission;

[0044] Fig.21 showing an exemplary DCI dynamic scheduling of sidelink transmissions with retransmissions based on HARQ feedback; and

[0045] Fig. 22 Shown is an exemplary DCI dynamically scheduled sidelink transmission with retransmission based on HARQ feedback and early termination of transmission over the Uu interface. DETAILED DESCRIPTION

[0046] Issue 1: In New Radio (NR) V2X Mode 1, the base station schedules the sidelink resources used by the UE for sidelink communication. NR V2X should support dynamic resource allocation, activation\deactivation based resource allocation, and RRC (pre-)configured resource allocation for the sidelink. Mechanisms need to be introduced to support the aforementioned NR V2X resource allocation techniques.

[0047] In LTE Mode 3, the time domain resources used for V2X sidelink transmissions should be based on a pre-configured subframe resource pool. The granularity of the pool-based resource allocation is the subframe. In NR V2X, both non-periodic and periodic traffic on the sidelink should be supported. This subframe-based resource allocation design may not meet the latency requirements. Therefore, Uu-based resource allocation needs to be enhanced to support lower latency.

[0048] Issue 2: In NR V2X Mode 1, broadcast, multicast or unicast sidelink communications should also be supported. In LTE V2X, only broadcast sidelink communications are supported. Therefore, mechanisms need to be introduced to allocate resources for groupcast or unicast sidelink communications in NR V2X. The UE may be configured with multiple resources for broadcast, multicast or unicast sidelink communications. When the UE receives a scheduling grant, the UE should be able to determine for which type of sidelink communication the received grant is used. Mechanisms need to be introduced to address this issue.

[0049] The UE may be configured with multiple resources for broadcast, multicast or unicast sidelink communications. When the UE receives a scheduling grant, the UE should be able to determine for which type of sidelink communication the received grant is used. Mechanisms need to be introduced to address this issue.

[0050] In LTE V2X, the receiver UE keeps trying to decode the Physical Sidelink Control Channel (PSCCH) at every candidate PSCCH resource configured by higher layers. While this is acceptable for LTE due to the relatively sparse V2X reception resources in terms of time, this may be very power inefficient in NR given the NR V2X requirements where the density of V2X reception monitoring opportunities may be much higher. For example, in NR V2X, the UE may be configured with multiple resources for broadcast, multicast, and unicast sidelink communications. In addition, the NR V2X reception resource configuration needs to take care of not only periodic traffic, but also non-periodic traffic, which may require the configuration of different resource sets. Therefore, the current design for receiving PSCCH in LTE, if applied to NR as is, may cause huge power consumption issues in NR, as the number of PSCCH blind decodings may increase dramatically.

[0051] Disclosed herein are different sidelink resource configuration and allocation schemes that may be controlled through an interface, such as a Uu interface.

[0052] Uu-based dynamic resource grant allocation for sidelink

[0053] Broadcast sidelink transmission

[0054] Broadcast sidelink transmission: In NR V2X, the gNB (e.g. Figure 3 or Fig. 9A gNB 201) or a node like a gNB (e.g., a base station) may dynamically assign a UE (e.g., Figure 3 or Fig. 9A The UE may be assigned resources for broadcasting sidelink transmissions via RRC configuration and DCI signaling. When the UE receives the scheduling DCI, the UE may broadcast control and data on the sidelink using the scheduled resources. The detailed resource allocation scheme is as follows.

[0055] Detailed design for RRC configuration: The UE may be configured with one or more information elements (IEs), each of which specifies configuration information of resources for NR V2X sidelink transmission. In order to support broadcast, groupcast, and unicast sidelink transmissions in NR V2X, different IEs are disclosed herein, for example, NR-SL-Resource-Broadcast, NR-SL-Resource-Groupcast, or NR-SL-Resource-Unicast may be used to configure information of resources for sidelink transmission; or the same IE (e.g., NR-SL-Resource) may be used when the type of sidelink transmission (e.g., broadcast, multicast, or unicast) is specified in the IE.

[0056] For broadcast sidelink transmission, IE NR-SL-Resource or NR-SL-Resource-Broadcast may carry configuration information for sidelink control or sidelink data transmission. The UE may be configured with NR-SL-Resource or NR-SL-Resource-Broadcast via a broadcast signal (e.g., OSI) or via a public or dedicated RRC configuration on the Uu interface. It is disclosed herein that IE NR-SL-Resource or NR-SL-Resource-Broadcast may carry the following RRC configurations: 1) type of sidelink transmission; 2) type of carrier; 3) parameter set of resources; 4) broadcast transmitting UE; 5) mask for scrambling the scheduled DCI; 6) index of candidate resources; 7) candidate time domain resources for resource configuration; 8) number of repetitions and redundant versions; 9) candidate frequency domain resources for resource configuration; or 10) beam scanning, etc.

[0057] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE NR-SL-Resource is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0058] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource allocation is for a shared licensed carrier between Uu and the sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource allocation is for a dedicated sidelink carrier.

[0059] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configures NR-SL-Numerology, which can be 15, 30, 60KHz, etc. Or the parameter set can be configured according to BWP.

[0060] RRC configuration for indicating a broadcast transmit UE sidelink ID on the sidelink. For a broadcast sidelink transmit, the UE may be configured with the UE ID on the sidelink as a source ID or a destination ID. For example, the UE may be configured with a sidelink broadcast transmit RNTI (SL-BT-RNTI) for use as a source ID. The UE may be configured with a sidelink broadcast receive RNTI (SL-BR-RNTI) for use as a destination ID, where each destination ID may be associated with a different service.

[0061] When generating sidelink control information (SCI) for broadcast sidelink transmission, the scrambling sequence for SCI can be initialized jointly by the source ID and the destination ID. Or the scrambling sequence for SCI can be initialized by one of the source ID and the destination ID, the other of which is indicated in the SCI payload. For example, the destination ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0062] RRC configuration to indicate the mask used to scramble the scheduling DCI. For example, the UE may be configured with SLBroadcast-RNTI or SL-RNTI. The gNB may generate and send a scheduling DCI for the UE with a CRC scrambled by the configured SLBroadcast-RNTI or SL-RNTI. The UE may decode the DCI by using the configured SLBroadcast-RNTI or SL-RNTI.

[0063] RRC configuration for indicating the index of candidate resources. The UE may be configured with multiple configurations of resources for sidelink transmission, for example, multiple resource pools. Each configuration of resources may be associated with a dedicated resource index. For example, RRC configuration NR-SL-Resource-Index. The UE may determine the configuration of resources for sidelink transmission via DCI that schedules sidelink transmission.

[0064] An RRC configuration for indicating candidate time domain resources for resource configuration (e.g., time domain resources for each resource pool). As disclosed herein, the candidate time domain resources for broadcast sidelink transmission of each candidate resource may be configured with the following alternatives:

[0065] Alternative 1 - Candidate time domain resources: The UE may be configured with one or more bitmaps via an RRC configuration for indicating candidate time domain resources for sidelink transmission. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0066] When the UE receives a DCI carrying a scheduling grant for a transmission on the sidelink, the UE may perform the transmission starting from the next available time resource within the configured candidate time resources. A minimum time gap restriction may be applied to the UE to switch from a receive mode to a transmit mode, and the UE may perform the transmission starting from the next available time resource within the configured candidate time resources after the minimum time gap.

[0067] Alternatively, the UE may be configured with an offset value indicating a time resource within the configured candidate time resource to be used for sidelink transmission. The offset value may be transmitted by the DCI carrying the scheduling grant. The offset value may indicate an offset between the time resource used for sidelink transmission and the time resource used to send the scheduling grant DCI; or the offset value may indicate an offset between the time resource used for sidelink transmission and the next available time resource after the minimum time gap within the configured candidate time resource.

[0068] Alternative 2 - Candidate time domain resources: The UE may be dynamically informed of the time resources for broadcast sidelink transmissions through DCI. The UE may be configured with candidate time domain resources without RRC configuration. The DCI carrying the scheduling grant may indicate the time resources for broadcast sidelink transmissions.

[0069] RRC configuration for indicating beam scanning information. For broadcast sidelink transmission, the transmitter UE 202 may broadcast information to multiple directions using multiple beams. The UE needs to know the number of beam scannings it needs to perform and the corresponding resources.

[0070] Alternative 1 - Beam scanning information: The gNB may determine the number of beam scans that the UE should perform. For example, the UE may be configured with the number or maximum number of beam scans via RRC configuration. Using another alternative, the number of beam scans may be notified via DCI. The UE may provide assistance information to a Node B (e.g., a base station such as a gNB or eNB) to assist the NB in ​​determining the beam scanning configuration. Such assistance information may include one or more of the following: V2X services of interest, UE capabilities, such as in terms of the number of simultaneous beam scanning directions that the UE can cover, UE scheduling preferences (including power saving mode preferences), etc.

[0071] Assuming that the UE is configured to broadcast information through k directions / beams, the UE may be assigned k configurations of time and frequency resources, for example, time and frequency resources for each direction / beam, respectively, through RRC configuration and DCI signaling for beam scanning in k directions. If the UE needs to broadcast in k directions, the UE needs to generally form k beams (thus, k directions / beams), each beam aimed at one direction. The UE is able to perform beam scanning of the k formed beams to cover all directions.

[0072] Or the UE may be assigned a configuration of time and frequency resources. According to one possibility, the assigned time and frequency resources may be used for all beams. The UE may evenly divide the assigned time resources into k parts and use each part for one beam. According to another possibility, the assigned time and frequency resources may be used for one beam. For example, the UE may use the time resources in each beam scanning direction as follows. In option 1 of this alternative 1 for beam scanning, the UE may use the assigned time and frequency resources for the first beam scanning, and use the next available time resources in the configured resource pool with the same duration and the same frequency resources as the time and frequency resources used for the first beam scanning for the remaining beam scanning. For example, assume that the UE is configured with time resources in a mini-slot, and the UE is configured to use mini-slot n for the first beam scanning. The UE may use mini-slots n+1 to n+k-1 in the configured resource pool for the remaining beam scanning. The beam used for beam scanning may be indicated by the gNB. Or the beam used for beam scanning may be determined autonomously by the transmitter UE 202 based on sensing or discovery. In option 2 of this alternative 1 for beam scanning, the UE may slice the time resources equally in each beam scanning direction cyclically and may use the same 1 frequency resource in each direction. In option 3 of this alternative 1 for beam scanning, the UE may autonomously decide how to slice the time-frequency resources in both the time domain and the frequency domain in each beam scanning direction.

[0073]

[00136] Alternative 2 - Beam scanning information: The UE may determine the number of beam scans that the UE needs to perform for the broadcast sidelink transmission. The UE may report the value of k beam scans to the gNB. The gNB may schedule time resources for the UE for the broadcast sidelink transmission.

[0074] The UE may be assigned k configurations of time and frequency resources through RRC configuration and DCI signaling for beam scanning in k directions, respectively. Or the UE may be assigned one configuration of time and frequency resources. According to one possibility, the assigned time and frequency resources may be used for all beams. The UE may evenly divide the assigned time resources into k parts and use each part for one beam. According to another possibility, the assigned time and frequency resources may be used for one beam. For example, the UE may use the assigned time and frequency resources for the first beam scanning, and use the next available time resources in the configured resource pool with the same duration and the same frequency resources as the time and frequency resources used for the first beam scanning for the remaining beam scanning. The beam used for beam scanning may be indicated by the gNB. Or the beam used for beam scanning may be autonomously determined by the transmitter UE202 based on sensing or discovery.

[0075] An RRC configuration for indicating candidate frequency domain resources for resource configuration (e.g., frequency domain resources for each resource pool). The UE may be configured with one or more SL-BWPs. Or the UE may be configured with one or more candidate frequency resources for broadcast sidelink transmission. We disclose that the candidate frequency resources may be configured using the following alternatives:

[0076] Alternative 1 - Candidate frequency domain resources: The UE may be configured with continuous frequency resources as candidate frequency resources for sidelink broadcast transmissions. Frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). For example, the UE may be configured with parameters StartRB and LengthRB through RRC configuration to indicate the start and length value (SLV) of the RB used for the candidate frequency resources. Or the UE may be configured with parameters StartRBG and LengthRBG through RRC configuration to indicate the SLV of the RBG used for the candidate frequency resources. The UE may be configured with one candidate frequency resource for both sidelink control information (SCI) transmission and sidelink data transmission. The UE may also be configured with two candidate frequency resources for sidelink control information (SCI) transmission and sidelink data transmission, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0077] Alternative 2 - Candidate frequency domain resources: The UE may be configured with non-contiguous frequency resources as candidate frequency resources for sidelink broadcast transmissions. Frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). Non-contiguous frequency resources may be configured via multiple SLVs. For example, StartRBG_1 and LengthRBG_1, StartRBG_2 and LengthRBG_2, ..., StartRBG_m and LengthRBG_m. Alternatively, non-contiguous frequency resources may be configured via a start value and a bitmap. For example, StartRBG and {b m-1 ,…,b1,b0}. Assume that the UE is configured with StartRBG, StartRBG is set to k, b m-1 is mapped to RBG k and b0 is mapped to RBG k+m.

[0078] For the above alternatives, the UE may provide assistance information, for example in a Sidelink UE Information message or in a UE Assistance Information message or similar message, to assist the NB in ​​appropriately configuring the UE. Such assistance information may include various information, such as UE capabilities, carrier frequencies on which the UE is interested in sending or receiving V2X communications or performing V2X discovery, V2X services of interest to the UE, and specific BWPs within carrier frequencies on which the UE is interested in sending or receiving V2X communications or performing V2X discovery. It should be noted that in LTE, this procedure may be used to inform the E-UTRAN of the UE's power saving preferences and SPS assistance information, maximum physical downlink shared channel / physical uplink shared channel (PDSCH / PUSCH) bandwidth configuration preferences, etc., while the Sidelink UE Information message (if used) is used to inform the NB that the UE is interested or no longer interested in receiving sidelink communications or discovery, receiving V2X sidelink communications, and requesting the allocation or release of transmission resources for V2X sidelink communications, V2X sidelink discovery gaps, etc.

[0079] It should be noted that the aforementioned RRC configuration may be configured through IE NR-SL-Resource or NR-SL-Resource-Broadcast, or some of the aforementioned RRC configurations may be configured through other IEs for side link configuration.

[0080] Detailed design for DCI signaling: The UE may be dynamically notified of scheduling grants via the DCI for broadcast sidelink transmission. For example, a new DCI format (e.g., DCI format 3) may be used to schedule PSCCH and physical sidelink shared channel (PSSCH) for broadcast sidelink transmission. To support dynamic scheduling of resources for broadcast, groupcast, or unicast sidelink transmission, the gNB may dynamically send scheduling DCI. To distinguish the scheduling DCI, different RNTIs may be used to scramble the CRC of the DCI for scheduling broadcast, groupcast, or unicast sidelink transmission. For example, SLBroadcast-RNTI, SLGroup-RNTI, SLUnicast-RNTI may be used to scramble the CRC of the DCI for scheduling broadcast, groupcast, or unicast, respectively. The UE may be configured with SLBroadcast-RNTI, SLGroup-RNTI, SLUnicast-RNTI via RRC configuration.

[0081] Alternatively, one RNTI may be used to scramble the cyclic redundancy check (CRC) of a DCI used to schedule broadcast, multicast, or unicast sidelink transmissions. For example, the same RNTI (e.g., SL-RNTI) may be used to scramble the CRC of a DCI used to schedule broadcast, multicast, or unicast. A field in a scheduling DCI may be used to indicate that the DCI is used for scheduling broadcast, multicast, or unicast.

[0082] In order to schedule resources for broadcast sidelink transmission, we disclose that the scheduling DCI can carry the following information: 1) BWP indicator field; 2) resource indicator field; 3) sidelink type indicator field; 4) carrier type indicator field: 5) time domain resource management field; 6) beam scanning information field; 7) frequency domain resource allocation field; or 8) slot format indicator (SFI) field, etc.

[0083] Bandwidth Part (BWP) Indicator Field. The UE may be configured with multiple BWPs via RRC configuration for sidelink communications. The scheduling DCI may indicate the BWP to be used for broadcast sidelink transmissions. Or the scheduling DCI may instruct the UE to switch from the current BWP to a new BWP. The BWP Indicator Field may indicate the index of the BWP that the UE needs to use to perform broadcast sidelink transmissions or that the UE needs to switch to. Assuming that the UE is configured with 4 BWPs, a 2-bit BWP Indicator Field may be used, with "00" indicating the first configured BWP, "01" indicating the second configured BWP, and so on. Some fields may be dedicated in the bitmap and used to indicate the initial BWP and the default BWP. For example, "00" may indicate the initial BWP used for, for example, discovery and synchronization. Alternatively, "00" may indicate the default BWP. In another alternative, "00" may indicate the initial BWP, and "01" may indicate the default BWP.

[0084] Resource Indicator Field. The UE may be configured with multiple configurations of resources, e.g., multiple resource pools, via RRC. The scheduling DCI may indicate the index of the configuration of resources to be used for broadcast sidelink transmissions. Assuming the UE is configured with 8 configurations of resources, e.g., configuration 0 to configuration 7, a 3-bit resource indicator field may be used, with "000" indicating configuration 0, "001" indicating configuration 1, and so on.

[0085] Sidelink Type Indicator Field. The scheduled DCI may indicate the type of sidelink transmission. For example, a 2-bit Sidelink Type Indicator field may be used, with "00" indicating that the DCI is scheduling a broadcast sidelink transmission, "01" indicating that the DCI is scheduling a multicast sidelink transmission, "10" indicating that the DCI is scheduling a unicast sidelink transmission, and so on.

[0086] Carrier type indicator field. Using one bit in the scheduling DCI, the UE can be dynamically indicated the type of carrier. For example, if the carrier type indicator field is set to "0", the UE determines that the sidelink resource allocation is for the shared licensed carrier between Uu and the sidelink; if the carrier type indicator field is set to "1", the UE determines that the sidelink resource allocation is for the dedicated sidelink carrier.

[0087] Time Domain Resource Allocation Field. The UE may be informed of the scheduled time domain resources via DCI using the following alternatives.

[0088] Alternative 1 - Time domain resource allocation: The UE may be configured with one or more candidate resources through RRC configuration. The scheduling DCI may indicate the time domain resources among the candidate resources to be used for the broadcast sidelink transmission.

[0089] In order to determine the start of the time domain resources, the UE may be notified of the time offset indicator. For example, the time offset value field may be carried by the scheduling DCI to indicate the number of time units between the scheduling DCI and the scheduled time domain resources for broadcast sidelink transmission. The time unit may be a subframe, a time slot, a mini-time slot, or a symbol. Or the UE may be indicated with a two-level time offset to determine the starting point of the time domain resources. For example, the UE may be indicated with a time slot / subframe (in other words, a time slot or a subframe) offset to determine which time slot / subframe the time domain resources start from. Then, the UE may be indicated with an index of the starting symbol / mini-time slot (in other words, a time slot or a mini-time slot) to determine the starting point within the time slot / subframe. In one example, the two-level time offset may be indicated separately by two DCI fields, for example, by a time slot level offset indicator field and a starting symbol indicator field.

[0090] In another example, the two-stage time offset may be indicated by a DCI field. For example, a table may include a combination of a slot level offset and a start symbol, which may be predefined or (pre) configured by RRC configuration, and each combination may be associated with an index. The UE may be notified of an index by the scheduling DCI via the DCI field. The UE may determine the time domain starting point by finding the corresponding two-stage offset from the table. The example shown here may also be applied to dynamic resource allocation for multicast sidelink transmission or unicast sidelink transmission.

[0091] To determine the duration of the time domain resources, the length of the bitmap or duration may be indicated by the scheduling DCI. In an example, the UE may be informed of the bitmap. The bitmap may indicate which time resources within the candidate resources configured by the radio resource control (RRC) are used for broadcast sidelink transmission. In another example, the UE may be informed of the length of the time domain resources, for example, 1. The UE may then use 1 consecutive resource units within the candidate resources configured by the RRC for broadcast sidelink transmission. The resource unit may be a subframe, a time slot, a mini-time slot, or a symbol.

[0092] The fields for indicating the start and duration of the time domain resource may also be notified through a DCI field. For example, a predefined or preconfigured table may contain combinations of the start and duration of the time domain resource, each combination being associated with an index. The UE may be notified of an index through a DCI field by the scheduling DCI. The UE may determine the time domain resource by finding the corresponding start or duration value from the table.

[0093] Alternative 2 - Time Domain Resource Assignment: The UE may be configured with candidate resources without RRC configuration. The UE may be dynamically indicated the time domain resources for broadcast sidelink transmission through scheduling DCI. DCI may carry information of time domain resources, such as time slot / subframe offset, starting point, duration, etc. The time slot / subframe offset may be relative to the time slot / subframe used for DCI reception. The aforementioned parameters may be indicated by different DCI fields, or may be indicated jointly by DCI fields. For example, the time domain resources may be dynamically notified only through the scheduling DCI through the time slot / subframe offset value and SLV.

[0094] For broadcast sidelink transmission, the UE may send the same information in multiple directions. The UE may be indicated one time domain resource, and the time domain resources for all directions are determined by some predefined rules. Or the UE may be indicated the time domain resources for each direction separately. For example, the UE may be indicated multiple start and duration values ​​of the time domain resources. Or the UE may be indicated the gap between the time domain resources for transmission in the first direction and the transmission in the remaining directions.

[0095] For broadcast sidelink transmissions, the scheduling DCI may indicate the time domain resources used for PSCCH or PSSCH, such as Figure 1 As shown in . The time domain resources for PSCCH or PSSCH may be jointly allocated by the scheduling DCI, for example, one time domain resource allocation may be used for PSCCH or PSSCH. For example, in one scheme, the UE may receive one time domain resource allocation indicating resources for PSCCH and PSSCH. When PSCCH and PSSCH are FDMed, the UE may send PSCCH and PSSCH using different frequency resources on the allocated time resources.

[0096] When PSCCH or PSSCH is TDM or sent on different time resources, the UE may determine the time resources for PSCCH or PSSCH, respectively, within the scheduled time resources. For example, the UE may be statically configured via RRC, or dynamically indicated by a scheduling DCI having the number of symbols spanned by the PSCCH (e.g., k symbols). Then, if PSCCH and PSSCH are TDM, the UE may send PSCCH using the first k symbols in the allocated time resources, and send PSSCH using the remaining symbols. Or if the bandwidth of the PSCCH is smaller than the bandwidth of the PSSCH, the UE may send PSCCH and PSSCH using the first k symbols in the allocated time resources according to the frequency domain resource allocation, and send PSSCH using the remaining symbols.

[0097] In another scheme, the UE may receive a time domain resource allocation indicating resources for the PSSCH, and the UE determines the time domain resources for the PSCCH accordingly, and vice versa. The scheduled PSCCH and PSSCH may be located in the same time slot, or may be located in different time slots. For example, the UE may be statically configured with an offset between the PSCCH and the PSSCH through an RRC configuration, wherein the RRC configuration may include a slot-level offset or a symbol-level offset. The UE may be indicated by scheduling the DCI for the time domain resource allocation for the PSSCH, and the time domain resources for the associated PSCCH are determined based on the configured offset. The example shown here may also be applied to dynamic resource allocation for multicast sidelink transmission and unicast sidelink transmission.

[0098] Or the time domain resources for PSCCH and PSSCH may be separately allocated by the scheduling DCI. For example, the scheduling DCI may allocate two time domain resources for PSCCH and PSSCH respectively. For example, a DCI field for time domain resource allocation for PSCCH and a DCI field for time domain resource allocation for PSSCH, each of which may indicate an index corresponding to an entry in the RRC configuration. For example, the UE may be separately configured with an information element PSCCH_AllocationList and an information element PSSCH_AllocationList through RRC.

[0099] The information element PSCCH_AllocationList may contain a list of configured time domain resource allocations (one or more) for the PSCCH, e.g., a list of information elements PSCCH_TimeDomainResourceAllocation, where each indexed row configures a time slot offset (e.g., kx), a start and length indicator SLIV, etc. between the scheduled DCI and the scheduled PSCCH. An example of the information element PSCCH-TimeDomainResourceAllocationList is shown in Fig.17 Assuming that 3 bits are used in the PSCCH time domain resource allocation field, an example is shown in Table 1. The examples shown here for PSCCH can also be applied to dynamic resource allocation for multicast sidelink transmission and unicast sidelink transmission.

[0100] In the scenario of multicast side link transmission or unicast side link transmission, level 2 SCI can be used. In the scenario of using level 2 SCI, the UE can be explicitly indicated / configured (in other words, indicated or configured) for the time domain resource allocation for the transmission of the first level SCI, for example, through the DCI field first level PSCCH time domain resource allocation field and the information element First_Stage_PSCCH_TimeDomainResourceAllocation. In this case, the time slot offset kx represents the time slot offset between the scheduled DCI and the scheduled first level PSCCH. The UE can be jointly indicated for the time domain resource allocation for the transmission of the second level SCI and PSSCH, for example, through the DCI field PSSCH time domain resource allocation field. Then, the UE can derive the time domain resources for the second level SCI transmission or the time domain resources for the PSSCH transmission from the received PSSCH time domain resource allocation field using, for example, the method provided above.

[0101] Table 1 Example of PSCCH time domain resource allocation field

[0102]

[0103] The information element PSSCH_AllocationList may include a list of (one or more) configured time domain resource allocations for PSSCH, for example, a list of information elements PSSCH_TimeDomainResourceAllocation, where each indexed row configures a time slot offset (e.g., ky), a start and length indicator value (SLIV), etc. For the time slot offset ky, in one embodiment, it can be the time slot offset between the scheduled DCI and the scheduled PSSCH. In another embodiment, the time slot offset ky can be the time slot offset between the scheduled PSCCH and the scheduled PSSCH. An example of the information element PSSCH-TimeDomainResourceAllocationList is shown in Fig.18 Assuming that 4 bits are used in the PSSCH time domain resource allocation field, an example is shown in Table 2. The example shown here can also be applied to dynamic resource allocation for multicast sidelink transmission and unicast sidelink transmission.

[0104] In a multicast sidelink transmission or unicast sidelink transmission scenario, a 2-level SCI may be used. In a scenario using a 2-level SCI, the time slot offset ky may be a time slot offset between a scheduled first-level PSCCH transmission and a scheduled PSSCH transmission; or may be a time slot offset between a scheduled first-level PSCCH transmission and a jointly scheduled second-level PSCCH and PSSCH transmission.

[0105] Table 2 Example of PSSCH time domain resource allocation field

[0106]

[0107] Beam scanning information field. The scheduling DCI may indicate the number of beam scans that the UE may need to perform. The UE may be dynamically informed of the value of the number of beam scans through the scheduling DCI. Or the RRC may configure multiple potential values ​​for the number of beam scans, each value being associated with an index. The UE may be informed of an index and determine the value of the number of beam scans. The beam used for beam scanning may be indicated by the gNB. Or the beam used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0108] Frequency domain resource assignment field. In order to determine the frequency domain resources for broadcast sidelink transmission, the UE may be indicated information of the lowest resource block (RB), resource block group (RBG) or subchannel to be used. The UE may be informed of the index of the lowest RB, RBG or subchannel. Or the UE may be informed of the offset between the lowest RB, RBG or subchannel of the frequency domain resource assignment and the lowest RB, RBG or subchannel of the candidate frequency domain resources configured by RRC. The offset can be an RB, RBG or subchannel.

[0109] To determine the range of the frequency domain resources, the width of the bitmap or frequency domain resources may be indicated by the scheduling DCI. For one example, the UE may be notified of the bitmap. The bitmap indicates which frequency resources within the candidate frequency resources configured by the RRC are used for broadcast sidelink transmission. For another example, the UE may be notified of the width of the frequency domain resources, for example, w. The UE may then use w consecutive RBs, RBGs, or subchannels for broadcast sidelink transmission.

[0110] For broadcast sidelink transmission, the UE may send the same information in multiple directions. The UE may be instructed to use one frequency domain resource for transmission in all directions. Alternatively, the UE may be informed of different frequency domain resources for transmission in different directions.

[0111] For broadcast sidelink transmissions, the scheduling DCI may indicate frequency domain resources for both PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be jointly allocated by the scheduling DCI, for example, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Or the frequency domain resources for PSCCH or PSSCH may be allocated separately by the scheduling DCI. For example, the scheduling DCI may allocate two frequency domain resources for PSCCH or PSSCH, respectively.

[0112] Slot Format Indicator (SFI) field. SFI may be introduced to support sidelink transmissions such as Figure 2 As shown in . Within a time slot, symbols used for sidelink transmission may be marked as "S". For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmission only on symbols marked as "S". Or the UE may perform sidelink transmission on symbols marked as "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmission only on symbols marked as "S". Symbols marked as "X" may be used as gaps for switching the transmit and receive modes of the UE.

[0113] If there is a conflict between the candidate time resources configured by RRC and the SFI notified by DCI, the DCI may rewrite the RRC configuration. The UE may skip the conflicting symbols and not perform side link transmission on them. For example, assume that symbol k in time slot m is configured as a candidate time resource in the RRC configuration. If symbol k in time slot m is marked as "D" in the SFI, the UE may not regard symbol k in time slot m as a candidate time resource. When the UE determines the time resource for broadcasting side link transmission, the UE may skip symbol k in time slot m. If the candidate time resource is in a mini slot and there is a conflict for a portion of the symbols in the mini slot, the UE may skip the entire mini slot and not perform side link transmission on it. Or the UE may only skip the conflicting symbols and perform side link transmission on non-conflicting symbols within the mini slot.

[0114] Unicast sidelink transmission

[0115] Unicast sidelink transmission: In NR V2X, the gNB or a node like the gNB can dynamically allocate resources for unicast sidelink communication by the UE. For the transmitter UE 202, the UE can be allocated resources for unicast sidelink transmission through RRC configuration and DCI signaling. For the receiver UE 203, the UE can be allocated resources for unicast sidelink reception through RRC configuration and DCI signaling. When the gNB schedules transmission on the sidelink, the transmitter UE 202 or the receiver UE 203 can receive a scheduling grant. By receiving the scheduling grant, the transmitter can determine the resources and beams for transmission. By receiving the scheduling grant, the receiver UE 203 can determine the resources or beams for reception. Similar ideas can also be applied to multicast sidelink transmission. The detailed resource allocation scheme is as follows.

[0116] Detailed design for RRC configuration: For unicast sidelink transmission, IE NR-SL-Resource or NR-SL-Resource-Unicast may carry configuration information for both sidelink control and sidelink data transmission. The UE may be configured with NR-SL-Resource or NR-SL-Resource-Unicast via a broadcast signal (e.g., OSI) or via a public or dedicated RRC configuration on the Uu interface. IE NR-SL-Resource or NR-SL-Resource-Unicast may carry the following RRC configurations: 1) type of sidelink transmission; 2) type of carrier; 3) parameter set of resources; 4) broadcast transmitting UE; 5) mask for scrambling the scheduling DCI; 6) index of candidate resources; 7) candidate time domain resources for resource configuration; 8) number of repetitions and redundant versions; or 9) candidate frequency domain resources for resource configuration, etc.

[0117] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE NR-SL-Resource is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0118] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource allocation is for a shared licensed carrier between Uu and the sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource allocation is for a dedicated sidelink carrier.

[0119] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0120] RRC configuration for indicating a unicast UE ID on the sidelink. For unicast sidelink communications, the UE may be configured with a UE ID, such as a sidelink unicast RNTI (SL-U-RNTI). For a transmitter UE 202, the UE may use the SL-U-RNTI as a source ID. For a receiver UE 203, the UE may use the SL-U-RNTI as a destination ID.

[0121] In order to perform unicast sidelink communication, the UE needs to know the information of the paired UE. For the transmitter UE 202, the ID of the paired UE is the destination ID. For the receiver UE 203, the ID of the paired UE is the source ID. The UE can be indicated the ID of the paired UE through RRC configuration or through scheduling DCI, for example, the sidelink unicast pairing RNTI (SL-UP-RNTI).

[0122] When generating an SCI for unicast sidelink transmission, the scrambling sequence for the SCI may be initialized jointly by the source ID and the destination ID. Or the scrambling sequence for the SCI may be initialized by one of the source ID and the destination ID, the other of which is indicated in the SCI payload. For example, the destination ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0123] RRC configuration to indicate the mask used to scramble the scheduling DCI. For example, the UE may be configured with a SLUnicast-RNTI or SL-RNTI. The gNB may generate and send the scheduling DCI for the UE with a CRC scrambled by the configured SLUnicast-RNTI or SL-RNTI. The UE may decode the DCI by using the configured SLUnicast-RNTI or SL-RNTI.

[0124] RRC configuration for indicating the index of candidate resources. The UE may be configured with multiple configurations of resources for sidelink transmission, for example, multiple resource pools. Each configuration of resources may be associated with a dedicated resource index. For example, RRC configuration NR-SL-Resource-Index. The UE may determine the configuration of resources for sidelink transmission via DCI that schedules sidelink transmission.

[0125] An RRC configuration for indicating candidate time domain resources for resource configuration (e.g., time domain resources for each resource pool). As disclosed herein, the candidate time domain resources for unicast sidelink transmission of each candidate resource may be configured with the following alternatives:

[0126] Alternative 1 - Candidate time domain resources: The UE may be configured with one or more bitmaps via an RRC configuration for indicating candidate time domain resources for sidelink transmission. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0127] When the UE receives a DCI carrying a scheduling grant for a transmission on the sidelink, the UE may perform the transmission starting from the next available time resource within the configured candidate time resources. A minimum time gap restriction may be applied to the UE to switch from a receive mode to a transmit mode, and the UE may perform the transmission starting from the next available time resource within the configured candidate time resources after the minimum time gap.

[0128] Alternatively, the UE may be configured with an offset value indicating a time resource to be used for sidelink transmission within the configured candidate time resources. The offset value may be notified by a DCI signal carrying a scheduling grant. The offset value may indicate an offset between a time resource used for sidelink transmission and a time resource used to send a scheduling grant DCI; or the offset value may indicate an offset between a time resource used for sidelink transmission and a next available time resource after a minimum time gap within the configured candidate time resources.

[0129] Alternative 2 - Candidate time domain resources: The UE may be dynamically informed of the time resources for unicast sidelink transmissions through DCI. The UE may be configured with candidate time domain resources without RRC configuration. The DCI carrying the scheduling grant may indicate the time resources for unicast sidelink transmissions.

[0130] RRC configuration to indicate the number of repetitions and the redundancy version (RV). To improve reliability, the UE may repeat unicast sidelink transmissions. The UE may be configured with the number of repetitions and the RV via RRC configuration via the gNB. In one example, the UE may be configured with one repetition number (e.g., k) in the RRC configuration. In another example, the UE may be configured with multiple repetition numbers (e.g., k1, k2, …, k i ). The log2(i)-bit repetition indicator field may be notified through the scheduling DCI to indicate to the UE the number of repetitions for the scheduled transmission.

[0131] Assuming i=4, an example of the repetition indicator field is shown in Table 3. In the example shown in Table 3, when the repetition indicator field is set to "00", it indicates that the number of repetitions is k1. In another example, when the repetition indicator field is set to "00", it indicates that the UE does not perform repetition; and "01", "10", "11" indicate that the number of repetitions is k1, k2, k3, respectively. Similar ideas can be applied to multicast sidelink transmission and broadcast sidelink transmission. When the UE repeats the initial transmission, inter-slot repetition or intra-slot repetition can be performed. The UE can use the same symbol or mini-slot in the subsequent time slot for repetition. Assuming that the initial transmission is scheduled in time slot n, in one example, the UE can send k repetitions in time slot n+1, time slot n+2, ..., time slot n+k; in another example, the UE can send k repetitions in time slot n+m, time slot n+2*m, ..., time slot n+k*m, where m is the gap between the initial transmission and the first repetition.

[0132] In this example, the unit of m is a time slot. In another example, the unit of m may be a mini-time slot or a symbol. For example, together with the RRC configuration configuring the number of repetitions and the redundant version, the value of m may be configured through RRC configuration; or the value of m may be dynamically notified by the scheduling DCI. Or the UE may use symbols or mini-time slots in the same time slot for repetition.

[0133] Table 3 Example of a repeat indicator field

[0134]

[0135]

[0136] An RRC configuration for indicating candidate frequency domain resources (e.g., frequency domain resources for each resource pool) for resource configuration. The UE may be configured with one or more SL-BWPs. Or the UE may be configured with one or more candidate frequency resources for unicast sidelink transmission. We disclose that the candidate frequency resources may be configured using the following alternatives:

[0137] Alternative 1 - Candidate frequency domain resources: The UE may be configured with continuous frequency resources as candidate frequency resources for sidelink unicast transmission. Frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). For example, the UE may be configured with parameters StartRB and LengthRB through RRC configuration to indicate the start and length value (SLV) of the RB for the candidate frequency resources. Or the UE may be configured with parameters StartRBG and LengthRBG through RRC configuration to indicate the SLV of the RBG for the candidate frequency resources. The UE may be configured with one candidate frequency resource for both sidelink control information (SCI) transmission and sidelink data transmission. The UE may also be configured with two candidate frequency resources for sidelink control information (SCI) transmission and sidelink data transmission, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0138] Alternative 2 - Candidate frequency domain resources: The UE may be configured with non-contiguous frequency resources as candidate frequency resources for sidelink unicast transmission. Frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). Non-contiguous frequency resources may be configured via multiple SLVs. For example, StartRBG_1 and LengthRBG_1, StartRBG_2 and LengthRBG_2, ..., StartRBG_m and LengthRBG_m. Or non-contiguous frequency resources may be configured via a start value and a bitmap. For example, StartRBG and {bm-1, ..., b1, b0}. Assuming the UE is configured with StartRBG, StartRBG is set to k, bm-1 is mapped to RBG k and b0 is mapped to RBG k+m.

[0139] For the above alternatives, the UE may provide assistance information, for example in a Sidelink UE Information message or in a UE Assistance Information message or similar message, to assist the NB in ​​appropriately configuring the UE. Such assistance information may include various information, such as UE capabilities, carrier frequencies on which the UE is interested in sending or receiving V2X communications or performing V2X discovery, V2X services of interest to the UE, specific BWPs within carrier frequencies on which the UE is interested in sending or receiving V2X communications or performing V2X discovery. It should be noted that in LTE, this procedure may be used to inform the E-UTRAN of the UE's power saving preferences and SPS assistance information, maximum PDSCH / PUSCH bandwidth configuration preferences, etc., while the Sidelink UE Information message (if used) may be used to inform the NB that the UE is interested or no longer interested in receiving sidelink communications or discovery, receiving V2X sidelink communications and requesting the allocation or release of transmission resources for V2X sidelink communications, V2X sidelink discovery gaps, etc.

[0140] It should be noted that the aforementioned RRC configuration may be configured through IE NR-SL-Resource or NR-SL-Resource-Unicast, or some of the aforementioned RRC configurations may be configured through other IEs for side link configuration.

[0141] Detailed design for DCI signaling: The UE can be dynamically notified of scheduling grants through the DCI for unicast sidelink transmission. For example, a new DCI format (e.g., DCI format 3) can be used to schedule PSCCH or PSSCH for unicast sidelink transmission. In order to schedule resources for unicast sidelink transmission, we disclose that the scheduling DCI can carry the following information: 1) BWP indicator field; 2) resource indicator field; 3) sidelink type indicator field; 4) carrier type indicator field: 5) transmit / receive indicator field; 6) sidelink UE ID field; 7) pairing UE ID field; 8) time domain resource assignment field; 9) retransmission field; 10) HARQ field; 11) CSI acquisition and reporting field; 12) frequency domain resource assignment field; or 13) slot format indicator (SFI) field, etc.

[0142] BWP indicator field: The UE may be configured with multiple BWPs through RRC configuration. The scheduling DCI may indicate the BWP to be used for unicast sidelink transmission. Or the scheduling DCI may instruct the UE to switch from the current BWP to a new BWP. The BWP indicator field may indicate the index of the BWP that the UE needs to use to perform unicast sidelink transmission or the UE needs to switch to. Assuming that the UE is configured with 4 BWPs, a 2-bit BWP indicator field may be used, "00" indicates the first configured BWP, "01" indicates the second configured BWP, and so on. Some fields may be dedicated in the bitmap and are used to indicate the initial BWP and the default BWP. For example, "00" may indicate the initial BWP (used for discovery and synchronization, for example). Alternatively, "00" may indicate the default BWP. In another alternative, "00" may indicate the initial BWP, and "01" may indicate the default BWP.

[0143] Resource Indicator Field: The UE may be configured with multiple configurations of resources, e.g., multiple resource pools, through RRC. The scheduling DCI may indicate the index of the configuration of resources to be used for unicast sidelink transmission. Assuming the UE is configured with 8 configurations of resources, e.g., configuration 0 to configuration 7, a 3-bit resource indicator field may be used, with "000" indicating configuration 0, "001" indicating configuration 1, and so on.

[0144] Sidelink Type Indicator Field: The scheduled DCI may indicate the type of sidelink transmission. For example, a 2-bit Sidelink Type Indicator field may be used, with "00" indicating that the DCI is scheduling a unicast sidelink transmission, "01" indicating that the DCI is scheduling a unicast sidelink transmission, "10" indicating that the DCI is scheduling a unicast sidelink transmission, and so on.

[0145] Carrier type indicator field: Using a bit in the scheduling DCI, the UE can be dynamically indicated the type of carrier. For example, if the carrier type indicator field is set to "0", the UE determines that the sidelink resource allocation is for the shared licensed carrier between Uu and the sidelink; if the carrier type indicator field is set to "1", the UE determines that the sidelink resource allocation is for the dedicated sidelink carrier.

[0146] Transmit / receive indicator field: In unicast sidelink communication, both the transmitter UE 202 and the receiver UE 203 may receive scheduling DCI. The transmit / receive indicator field may be notified by the scheduling DCI to indicate whether the DCI is scheduling transmission or reception. For example, a one-bit field may be used, "0" indicates reception and "1" indicates transmission.

[0147] Sidelink UE ID field: For unicast sidelink communications, the UE may be dynamically informed of the sidelink UE ID, e.g., SL-U-RNTI. For the transmitter UE 202, the UE may use the SL-U-RNTI as the source ID. For the receiver UE 203, the UE may use the SL-U-RNTI as the destination ID. The scheduling DCI may explicitly indicate the UE ID, e.g., SL-U-RNTI. Alternatively, the UE may be configured with 2 n UE IDs, where each UE ID is associated with an index. The scheduling DCI may use an n-bit field to indicate the index for the UE to determine the UE ID.

[0148] Pairing UE ID field: The UE may be dynamically informed of the ID of the paired UE. If the UE receives a scheduling DCI with the Send / Receive Indicator field set to "0", the Pairing UE ID field indicates the ID of the transmitter UE 202. If the UE receives a scheduling DCI with the Send / Receive Indicator field set to "1", the Pairing UE ID field indicates the ID of the receiver UE 203. The scheduling DCI may explicitly indicate the pairing UE ID, for example, SL-UP-RNTI. Or the UE may be configured with 2 through RRC. n The scheduling DCI may use an n-bit field to indicate the index for the UE to determine the pairing UE ID.

[0149] Time Domain Resource Allocation Field: The UE may be informed of the scheduled time domain resources via DCI using the following alternatives:

[0150] Alternative 1 - Time domain resource allocation: The UE may be configured with one or more candidate resources through RRC configuration. The scheduling DCI may indicate the time domain resources among the candidate resources to be used for unicast sidelink transmission.

[0151] In order to determine the start of the time domain resources, the UE may be notified of the time offset value. For example, the time offset value field may be carried by the scheduling DCI to indicate the number of time units between the scheduling DCI and the scheduled time domain resources for unicast sidelink transmission. The time unit may be a subframe, a time slot, a mini-time slot or a symbol. Or the UE may be indicated with a two-level time offset to determine the starting point of the time domain resources. For example, the UE may be indicated with a time slot / subframe offset to determine which time slot / subframe the time domain resources start from. Then, the UE may be indicated with an index of the starting symbol / mini-time slot to determine the starting point within the time slot / subframe. In order to determine the duration of the time domain resources, the length of the bitmap or duration may be indicated by the scheduling DCI. In an example, the UE may be notified of a bitmap. The bitmap may indicate which time resources within the candidate resources configured by the RRC are used for unicast sidelink transmission. In another example, the UE may be notified of the length of the time domain resources, for example, 1. Then, the UE may use l consecutive resource units within the candidate resources configured by the RRC for unicast sidelink transmission. The resource unit may be a subframe, a time slot, a mini-time slot or a symbol.

[0152] The fields for indicating the start and duration of the time domain resource may also be notified through a DCI field. For example, a predefined or preconfigured table may contain combinations of the start and duration of the time domain resource, each combination being associated with an index. The UE may be notified of an index through a DCI field by the scheduling DCI. The UE determines the time domain resource by finding the corresponding start and duration values ​​from the table.

[0153] Alternative 2 - Time Domain Resource Assignment: The UE may be configured with candidate resources without RRC configuration. The UE may be dynamically indicated the time domain resources for unicast sidelink transmission through scheduling DCI. DCI may carry information of time domain resources, such as time slot / subframe offset, starting point, duration, etc. The aforementioned parameters may be indicated by different DCI fields, or may be indicated jointly by DCI fields. For example, the time domain resources may be dynamically notified only through the scheduling DCI through the time slot / subframe offset value and SLV.

[0154] For unicast sidelink transmission, the scheduling DCI may indicate the time domain resources for both PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be jointly allocated by the scheduling DCI, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Or the time domain resources for PSCCH or PSSCH may be allocated separately by the scheduling DCI. For example, the scheduling DCI may allocate two time domain resources for PSCCH or PSSCH, respectively.

[0155] Retransmission field: HARQ feedback may be introduced on the unicast sidelink. When a transmission is NACKed at the receiver UE 203, the transmitter UE 202 may perform a retransmission.

[0156] The retransmission at the transmitter UE 202 may be triggered by the receiver UE 203, or may be triggered by the gNB. According to an alternative, the receiver UE 203 may feed back a NACK to the gNB. The gNB may trigger the transmitter UE 202 to perform the retransmission by sending another scheduling DCI for the retransmission. For the retransmission, the gNB may instruct the transmitter UE 202 to use the same MCS; or the gNB may instruct the transmitter UE 202 to use a different MCS. If repetition is performed, the UE may also be notified of a different RV for the repetition of the retransmission. For example, the scheduling DCI may carry an MCS index field to indicate a row index of a corresponding MCS level to be used for sidelink transmission in a predefined modulation and coding scheme (MCS) table; or indicate a row index of a corresponding MCS level to be used for sidelink transmission in an MCS table configured by RRC configuration.

[0157] The MCS table configured by RRC may be a subset of the predefined MCS table, for example, RRC configuration NR-SL-MCS may include the start index and end index of the predefined MCS table to configure the MCS table subset; or RRC configuration NR-SL-MCS may include the start index of the predefined MCS table or the size of the subset to configure the MCS table subset. The start index or the end index may be configured by a 5-bit length bit string in the RRC configuration. The size of the subset may be configured by an integer (e.g., 1, 2, 4, 8, etc.) in the RRC configuration.

[0158] Assuming that rows 10 to 17 of the predefined MCS table are configured as an MCS table subset through RRC configuration, the MCS index field will be 3 bits, and an example is shown in Table 4. When the UE is instructed to set the MCS index field to "001", the UE may use the second row of the configured MCS table subset, which in this example is row 11 of the predefined MCS table. The examples shown here may also be applied to dynamic resource allocation for multicast sidelink transmissions or broadcast sidelink transmissions. In this case, the retransmission field may be one bit to indicate whether the scheduling is for an initial transmission or for a retransmission. For example, "0" may indicate that the transmission is an initial transmission, and "1" may indicate that the transmission is a retransmission. An exemplary call flow is shown in Figure 3 middle.

[0159] Table 4 Example of MCS index field

[0160] The value of the MCS index field MCS value 000 The first row of the MCS table subset configured via RRC 001 The second row of the MCS table subset configured by RRC … … 111 The eighth row of the MCS table subset configured by RRC

[0161] Figure 3An exemplary call flow for gNB-triggered retransmission for unicast sidelink is shown. In step 211a, Tx UE 202 obtains (e.g., receives) scheduling DCI for initial transmission over Uu interface. In step 211b, Rx UE 203 obtains scheduling DCI for initial transmission over Uu interface. In step 212, Rx UE 203 obtains unicast transmission on sidelink. In step 213, based on step 212 or step 211b, Rx UE 203 sends HARQ feedback to gNB 201 over Uu interface. If NACK is received, steps 213 to 216 may be performed. In step 214, scheduling DCI for retransmission over Uu interface may be obtained by Tx UE 202. Based on step 214, in step 215, unicast retransmission on sidelink may be sent by Tx UE 202. In step 216, based on step 215, Rx UE 203 sends HARQ feedback to gNB via Uu interface. If ACK is received, steps 217 to 219 may be performed. In step 217, scheduling DCI for new transmission via Uu interface may be obtained by Tx UE 202. Based on step 217, in step 218, unicast transmission on the side link may be sent by Tx UE 202. In step 219, based on step 218, Rx UE 203 sends HARQ feedback to gNB via Uu interface.

[0162] According to another alternative, the receiver UE 203 may feed back a NACK to the transmitter UE 202. By receiving the NACK from the receiver UE 203, the transmitter UE 202 may perform a retransmission. For the retransmission, the transmitter UE 202 may choose to use the same MCS as the MCS used for the initial transmission; or the transmitter UE 202 may autonomously choose to use a different MCS. For one example, the transmitter UE 202 may autonomously select an MCS from the predefined MCS table. For another example, the transmitter UE 202 may autonomously select an MCS from a subset of the predefined MCS table, wherein the subset may be configured by RRC via RRC configuration NR-SL-MCS. The configuration details disclosed above may also be applied here. The examples shown here may also be applied to dynamic resource allocation for multicast sidelink transmission or broadcast sidelink transmission.

[0163] The resources for retransmission may be pre-reserved by a retransmission field in the scheduling DCI carrying the grant for the initial transmission. The retransmission field may indicate the time or frequency resource allocated for the retransmission, such as a symbol index, a mini-slot index, an RB index, etc. Or the retransmission field may indicate the time or frequency offset between the retransmission and the initial transmission, such as a symbol offset, a mini-slot offset, an RB offset, etc.

[0164] If the sender UE 202 receives a NACK from the receiver UE 203, the sender UE 202 may use the pre-reserved resources for retransmission. If the sender UE 202 receives an ACK from the receiver UE 203, the sender UE 202 may skip the pre-reserved resources for retransmission. An exemplary call flow is shown in Figure 4 middle.

[0165] Figure 4 An exemplary call flow for Rx UE 203 triggered retransmission for unicast sidelink is shown. In step 221a, Tx UE 202 obtains (e.g., receives) scheduling DCI for initial transmission via Uu interface. In step 221b, Rx UE 203 obtains scheduling DCI for initial transmission and retransmission via Uu interface. In step 222, Rx UE 203 obtains unicast transmission on sidelink from Tx UE 202. In step 223, based on step 222, Rx UE 203 sends HARQ feedback to Tx UE 202 on sidelink. If NACK is received, steps 224 to 225 may be performed. In step 224, unicast retransmission via sidelink may be obtained by Rx UE 203. Based on step 224, in step 225, Rx UE 203 sends HARQ feedback to Tx UE 202 via sidelink. If an ACK is received, for example, at step 223, the Tx UE 202 may skip retransmission.

[0166] HARQ field. The scheduling DCI may indicate the HARQ ID or HARQ process number to the transmitter UE 202 and the receiver UE 203. The scheduling DCI may also indicate resource allocation for HARQ feedback. The scheduling DCI may indicate the time or frequency resources for HARQ feedback, such as symbol index, mini-slot index, RB index, etc. Or the scheduling DCI may indicate the time or frequency offset between the HARQ feedback and the initial transmission, such as symbol offset, mini-slot offset, RB offset, etc. If the retransmission is triggered by the receiver UE 203, the receiver UE 203 may send the HARQ feedback to the transmitter UE 202 using the allocated HARQ feedback resources. If the retransmission is triggered by the gNB 201, the receiver UE 203 may send the HARQ feedback to the gNB 201 using the allocated HARQ feedback resources.

[0167] Channel State Information (CSI) Acquisition and Reporting Field. The gNB 201 may schedule CSI acquisition and reporting on the sidelink. The Scheduling DCI may indicate the CSI-RS configuration and resources used for reporting to the transmitter UE 202 and the receiver UE 203. The Scheduling DCI may indicate the time or frequency resources used for CSI feedback, such as symbol index, mini-slot index, RB index, etc. Multiple CSI-RS configurations may be configured through RRC, and the Scheduling DCI may notify the index to indicate the CSI-RS configuration used.

[0168] Frequency domain resource allocation field. In order to determine the frequency domain resources for unicast sidelink transmission / reception, the UE may be indicated with information of the lowest RB, RBG or subchannel to be used. The UE may be notified of the index of the lowest RB or RBG. Or the UE may be notified of the offset between the lowest RB, RBG or subchannel of the frequency domain resource allocation and the lowest RB, RBG or subchannel of the candidate frequency domain resources configured by RRC. The unit of the offset may be RB or RBG.

[0169] To determine the range of the frequency domain resources, the width of the bitmap or frequency domain resources may be indicated by the scheduling DCI. For one example, the UE may be notified of the bitmap. The bitmap indicates which frequency resources within the candidate frequency resources configured by the RRC are used for unicast sidelink transmission. For another example, the UE may be notified of the width of the frequency domain resources, for example, w. The UE may then use w consecutive RBs, RBGs, or subchannels for unicast sidelink transmission.

[0170] For unicast sidelink transmission, the scheduling DCI may indicate the frequency domain resources for both PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be jointly allocated by the scheduling DCI, for example, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Or the frequency domain resources for PSCCH or PSSCH may be allocated separately by the scheduling DCI. For example, the scheduling DCI may allocate two frequency domain resources for PSCCH or PSSCH, respectively.

[0171] Slot Format Indicator Field. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0172] If there is a conflict between the candidate time resources configured by RRC and the SFI notified by DCI, the DCI may rewrite the RRC configuration. The UE may skip the conflicting symbols and not perform side link transmission on them. For example, assume that symbol k in time slot m is configured as a candidate time resource in the RRC configuration. If symbol k in time slot m is marked as "D" in the SFI, the UE may not regard symbol k in time slot m as a candidate time resource. When the UE determines the time resources for unicast side link transmission, the UE may skip symbol k in time slot m. If the candidate time resource is in a mini slot and there is a conflict for a portion of the symbols in the mini slot, the UE may skip the entire mini slot and not perform side link transmission on it. Or the UE may only skip the conflicting symbols and perform side link transmission on non-conflicting symbols within the mini slot.

[0173] The symbols used for sidelink communication can be further divided into symbols for sidelink transmission and symbols for sidelink reception. As disclosed herein, the labels "ST" and "SR" can be introduced for time slot formats, such as Figure 5 as shown in . Figure 5 204. An example of a time slot format for a unicast sidelink is shown. For a transmitter UE 202, the UE may use symbols marked by the SFI as "ST" for sidelink transmissions, and may use symbols marked by the SFI as "SR" for receiving feedback, such as HARQ feedback. For a receiver UE 203, the UE may use symbols marked by the SFI as "ST" for receiving sidelink transmissions, and may use symbols marked by the SFI as "SR" for sending feedback, such as HARQ feedback. Similar ideas may also be applied to a multicast sidelink. Symbols marked as "X" may be used as gaps for switching the transmit and receive modes of the UE.

[0174] Multicast sidelink transmission

[0175] Multicast sidelink transmission: In NR V2X, gNB 201 or a node like gNB can dynamically allocate resources for multicast sidelink transmission by UE. For transmitter UE 202, the UE can be allocated resources for multicast sidelink transmission through RRC configuration and DCI signaling. For receiver UE 203, the UE can be allocated resources for reception through RRC configuration and DCI signaling. When gNB 201 schedules transmission on the sidelink, both transmitter UE 202 and receiver UE 203 can receive a scheduling grant. By receiving the scheduling grant, the transmitter can determine the resources and beams for transmission. By receiving the scheduling grant, the receiver UE 203 can determine the resources and beams for reception. The detailed resource allocation scheme is as follows.

[0176] Detailed design for RRC configuration: For multicast sidelink transmission, IE NR-SL-Resource or NR-SL-Resource-Groupcast may carry configuration information for both sidelink control and sidelink data transmission. The UE may be configured with NR-SL-Resource or NR-SL-Resource-Groupcast via a broadcast signal (e.g., OSI) or via a public or dedicated RRC configuration on the Uu interface. IE NR-SL-Resource or NR-SL-Resource-Groupcast may carry the following RRC configurations: 1) type of sidelink transmission; 2) type of carrier; 3) parameter set of resources; 4) multicast transmitting UE; 5) mask for scrambling the scheduling DCI; 6) index of candidate resources; 7) candidate time domain resources for resource configuration; 8) number of repetitions and redundant versions; 9) candidate frequency domain resources for resource configuration; or 10) beam scanning information, etc.

[0177] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE NR-SL-Resource is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0178] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource allocation is for a shared licensed carrier between Uu and the sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource allocation is for a dedicated sidelink carrier.

[0179] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0180] RRC configuration for indicating UE ID for multicast transmission on sidelink. For multicast sidelink transmission, the UE may be configured with a UE ID, for example, a sidelink multicast RNTI (SL-G-RNTI). If the UE needs to multicast on the sidelink, the UE may use the SL-G-RNTI as the source ID in the formed group.

[0181] In order to perform groupcast sidelink communications, the UE may need to be indicated with a group ID. The UE may be configured with a group ID, for example, a sidelink multicast destination RNTI (SL-GD-RNTI). The UE may use the configured group ID as the destination group ID. The group ID may also be dynamically notified by the scheduling DCI.

[0182] The scrambling sequence for SCI may be initialized jointly by the destination group ID and the source ID. Alternatively, the scrambling sequence for SCI may be initialized by one of the destination group ID or the source ID, the other of which is indicated in the SCI payload. For example, the destination group ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0183] RRC configuration for indicating the mask used to scramble the scheduling DCI. For example, the UE may be configured with a SLGroupcast-RNTI or SL-RNTI. gNB 201 may generate and send a scheduling DCI for the UE with a CRC scrambled by the configured SLGroupcast-RNTI or SL-RNTI. The UE may decode the DCI by using the configured SLGroupcast-RNTI or SL-RNTI.

[0184] RRC configuration for indicating the number of repetitions and redundancy version (RV). To improve reliability, the UE may repeat the multicast sidelink transmission. Through the gNB 201, the UE may be configured with the number of repetitions and the RV through RRC configuration. When the UE repeats the initial transmission, inter-slot repetition or intra-slot repetition may be performed. The UE may use the same symbol or mini-slot in a subsequent slot for repetition. Or the UE may use symbols or mini-slots in the same slot for repetition. If beam scanning is applied in multicast, the transmitter UE 202 may repeat the entire beam scanning, for example, beam 1, beam 2, ..., beam k, beam 1, beam 2, ..., beam k, ..., beam 1, beam 2, ..., beam k. Or the UE may repeat for each beam and then perform beam scanning, for example, beam 1, beam 1, ..., beam 1, beam 2, beam 2, ..., beam 2, ..., beam k, beam k, ..., beam k.

[0185] RRC configuration for indicating the index of candidate resources. The UE may be configured with multiple configurations of resources for sidelink transmission, for example, multiple resource pools. Each configuration of resources may be associated with a dedicated resource index. For example, RRC configuration NR-SL-Resource-Index. The UE may determine the configuration of resources for sidelink transmission via DCI that schedules sidelink transmission.

[0186] RRC configuration for indicating candidate time domain resources (e.g., time domain resources for each resource pool) for resource configuration. We disclose that the candidate time domain resources for multicast sidelink transmission for each candidate resource may be configured with the following alternatives:

[0187] Alternative 1 - Candidate time domain resources: The UE may be configured with one or more bitmaps via an RRC configuration for indicating candidate time domain resources for sidelink transmission. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot in the time interval and a0 is mapped to the last subframe or time slot. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0188] When the UE receives a DCI carrying a scheduling grant for a transmission on the sidelink, the UE may perform the transmission starting from the next available time resource within the configured candidate time resources. A minimum time gap restriction may be applied to the UE to switch from a receive mode to a transmit mode, and the UE may perform the transmission starting from the next available time resource within the configured candidate time resources after the minimum time gap.

[0189] Alternatively, the UE may be configured with an offset indicator for indicating a time resource within the configured candidate time resource to be used for the sidelink transmission. The offset value may be transmitted by the DCI carrying the scheduling grant. The offset value may indicate an offset between the time resource used for the sidelink transmission and the time resource used to send the scheduling grant DCI; or the offset value may indicate an offset between the time resource used for the sidelink transmission and the next available time resource after the minimum time gap within the configured candidate time resource.

[0190] Alternative 2 - Candidate time domain resources: The UE may be dynamically informed of the time resources for multicast sidelink transmissions through DCI. The UE may be configured with candidate time domain resources without RRC configuration. The DCI carrying the scheduling grant may indicate the time resources for multicast sidelink transmissions.

[0191] RRC configuration for indicating beam scanning information. For multicast sidelink transmission, the transmitter UE 202 can send information in multiple directions via multiple beams. The UE needs to know the number of beam scannings it needs to perform and the corresponding resources.

[0192] Alternative 1 - Beam scanning information: gNB 201 may determine the number of beam scans that the UE needs to perform. For example, the UE may be configured with the number or maximum number of beam scans via RRC configuration. Utilizing another alternative, the number of beam scans may be notified via DCI. The UE may provide assistance information to the NB to assist the NB in ​​determining the beam scanning configuration. Such assistance information may include one or more of the following: V2X services of interest, UE capabilities, such as in terms of the number of simultaneous beam scanning directions that the UE can cover, UE scheduling preferences (including power saving mode preferences), etc.

[0193] Assuming that the UE is configured to send information through k directions / beams, the UE can be assigned k configurations of time and frequency resources, for example, time and frequency resources for each direction / beam, through RRC configuration and DCI signaling for beam scanning in k directions, respectively.

[0194] Or the UE may be assigned a configuration of time and frequency resources. According to one possibility, the assigned time and frequency resources may be used for all beams. The UE may evenly divide the assigned time resources into k parts and use each part for one beam. According to another possibility, the assigned time and frequency resources may be used for one beam. For example, the UE may use the time resources in each beam scanning direction as follows. In option 1 of this alternative beam scanning information, the UE may use the assigned time and frequency resources for the first beam scanning, and use the next available time resources in the configured resource pool with the same duration and the same frequency resources as the time and frequency resources used for the first beam scanning for the remaining beam scanning. For example, assume that the UE is configured with time resources in a mini-slot, and the UE is configured to use mini-slot n for the first beam scanning. The UE may use mini-slots n+1 to n+k-1 in the configured resource pool for the remaining beam scanning. The beam used for beam scanning may be indicated by the gNB 201. Or the beam used for beam scanning may be determined autonomously by the transmitter UE 202 based on sensing or discovery. In option 2 of this alternative, the UE slices the time resources equally in each beam scanning direction cyclically and uses the same frequency resources in each direction. In option 3 of this alternative, the UE autonomously decides how to slice the time-frequency resources in both the time and frequency domains in the beam scanning direction.

[0195]

[00136] Alternative 2 - Beam Scanning Information: The UE may determine the number of beam scans that the UE needs to perform for the multicast sidelink transmission. The UE may report the value of k beam scans to the gNB 201. The gNB 201 schedules time resources for the UE for the multicast sidelink transmission.

[0196] The UE may be assigned k configurations of time and frequency resources through RRC configuration and DCI signaling for beam scanning in k directions, respectively. Or the UE may be assigned one configuration of time and frequency resources. According to one possibility, the assigned time and frequency resources may be used for all beams. The UE may evenly divide the assigned time resources into k parts and use each part for one beam. According to another possibility, the assigned time and frequency resources may be used for one beam. The UE may use the assigned time and frequency resources for the first beam scanning, and use the next available time resources in the configured resource pool with the same duration and frequency resources as the time and frequency resources used for the first beam scanning for the remaining beam scanning. The beam used for beam scanning may be indicated by the gNB 201. Or the beam used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0197] An RRC configuration for indicating candidate frequency domain resources (e.g., frequency domain resources for each resource pool) for resource configuration. The UE may be configured with one or more SL-BWPs. Or the UE may be configured with one or more candidate frequency resources for multicast sidelink transmission. We disclose that the candidate frequency resources may be configured using the following alternatives:

[0198] Alternative 1 - Candidate frequency domain resources: The UE may be configured with continuous frequency resources as candidate frequency resources for sidelink multicast transmission. Frequency resources may be configured per RB, or may be configured per subchannel (e.g., RBG). For example, the UE may be configured with parameters StartRB and LengthRB through RRC configuration to indicate the start and length value (SLV) of the RB used for the candidate frequency resources. Or the UE may be configured with parameters StartRBG and LengthRBG through RRC configuration to indicate the SLV of the RBG used for the candidate frequency resources. The UE may be configured with one candidate frequency resource for both sidelink control information (SCI) transmission and sidelink data transmission. The UE may also be configured with two candidate frequency resources for sidelink control information (SCI) transmission and sidelink data transmission, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0199] Alternative 2 - Candidate frequency domain resources: The UE may be configured with non-contiguous frequency resources as candidate frequency resources for sidelink multicast transmission. Frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). Non-contiguous frequency resources may be configured via multiple SLVs. For example, StartRBG_1 and LengthRBG_1, StartRBG_2 and LengthRBG_2, ..., StartRBG_m and LengthRBG_m. Or non-contiguous frequency resources may be configured via a start value and a bitmap. For example, StartRBG and {bm-1, ..., b1, b0}. Assuming the UE is configured with StartRBG, StartRBG is set to k, bm-1 is mapped to RBG k and b0 is mapped to RBG k+m.

[0200] For the above alternatives, the UE may provide assistance information, for example in a Sidelink UE Information message or in a UE Assistance Information message or similar message, to assist the NB in ​​appropriately configuring the UE. Such assistance information may include various information, such as UE capabilities, carrier frequencies on which the UE is interested in sending or receiving V2X communications or performing V2X discovery, V2X services of interest to the UE, specific BWPs within carrier frequencies on which the UE is interested in sending or receiving V2X communications or performing V2X discovery. It should be noted that in LTE, this procedure may be used to inform the E-UTRAN of the UE's power saving preferences and SPS assistance information, maximum PDSCH / PUSCH bandwidth configuration preferences, etc., while the Sidelink UE Information message (if used) is used to inform the NB that the UE is interested or no longer interested in receiving sidelink communications or discovery, receiving V2X sidelink communications and requesting the allocation or release of transmission resources for V2X sidelink communications, V2X sidelink discovery gaps, etc.

[0201] It should be noted that the above RRC configuration may be configured through IE NR-SL-Resource or NR-SL-Resource-Groupcast, or some of the above RRC configurations may be configured through other IEs for side link configuration.

[0202] Detailed design for DCI signaling: The UE can be dynamically notified of scheduling grants through the DCI for multicast sidelink transmission. For example, a new DCI format (e.g., DCI format 3) can be used to schedule PSCCH or PSSCH for multicast sidelink transmission. In order to schedule resources for multicast sidelink transmission, the scheduling DCI can carry the following information: 1) BWP indicator field; 2) resource indicator field; 3) sidelink type indicator field; 4) carrier type indicator field: 5) time domain resource allocation field; 6) send / receive indicator field; 7) sidelink UE ID field; 8) group ID field; 9) retransmission field; 10) HARQ field; 11) beam scanning information field; 12) frequency domain resource allocation field: or 13) slot format indicator (SFI) field, etc.

[0203] BWP indicator field. The UE may be configured with multiple BWPs through RRC configuration. The scheduling DCI may indicate the BWP to be used for multicast sidelink transmission. Or the scheduling DCI may instruct the UE to switch from the current BWP to a new BWP. The BWP indicator field may indicate the index of the BWP that the UE needs to use to perform multicast sidelink transmission or the UE needs to switch to. Assuming that the UE is configured with 4 BWPs, a 2-bit BWP indicator field may be used, "00" indicates the first configured BWP, "01" indicates the second configured BWP, and so on. Some fields may be dedicated in the bitmap and are used to indicate the initial BWP and the default BWP. For example, "00" may indicate the initial BWP (used for discovery and synchronization, for example). Alternatively, "00" may indicate the default BWP. In another alternative, "00" may indicate the initial BWP, and "01" may indicate the default BWP.

[0204] Resource indicator field. The UE may be configured with multiple configurations of resources, e.g., multiple resource pools, via RRC. The scheduling DCI may indicate the index of the configuration of resources to be used for multicast sidelink transmission. Assuming the UE is configured with 8 configurations of resources, e.g., configuration 0 to configuration 7, a 3-bit resource indicator field may be used, with "000" indicating configuration 0, "001" indicating configuration 1, and so on.

[0205] Sidelink Type Indicator Field. The scheduled DCI may indicate the type of sidelink transmission. For example, a 2-bit Sidelink Type Indicator field may be used, with "00" indicating that the DCI is scheduling a multicast sidelink transmission, "01" indicating that the DCI is scheduling a multicast sidelink transmission, "10" indicating that the DCI is scheduling a unicast sidelink transmission, and so on.

[0206] Carrier type indicator field. Using one bit in the scheduling DCI, the UE can be dynamically indicated the type of carrier. For example, if the carrier type indicator field is set to "0", the UE determines that the sidelink resource allocation is for the shared licensed carrier between Uu and the sidelink; if the carrier type indicator field is set to "1", the UE determines that the sidelink resource allocation is for the dedicated sidelink carrier.

[0207] Transmit / receive indicator field. In unicast sidelink communication, both the transmitter UE 202 and the receiver UE 203 may receive scheduling DCI. The transmit / receive indicator field may be notified by the scheduling DCI to indicate whether the DCI is scheduling transmission or reception. For example, a one-bit field may be used, "0" indicates reception and "1" indicates transmission.

[0208] Sidelink UE ID field. The UE may be dynamically informed of the UE ID in the sidelink group to indicate the source ID. The scheduling DCI may explicitly indicate the UE ID, for example, SL-G-RNTI. Or the UE may be configured with 2 n The scheduling DCI may use an n-bit field to indicate the index for the UE to determine the source ID.

[0209] The UE may be dynamically informed of the group ID to indicate the destination group ID. The scheduling DCI may explicitly indicate the group ID, for example, SL-GD-RNTI. Alternatively, the UE may be configured with 2 n The scheduling DCI may use an n-bit field to indicate the index for the UE to determine the group ID.

[0210] Time domain resource allocation field. The UE can be notified of the scheduled time domain resources through DCI using the following alternatives:

[0211] Alternative 1 - Time domain resource allocation: The UE may be configured with one or more candidate resources through RRC configuration. The scheduling DCI may indicate the time domain resource to be used for multicast sidelink transmission among the candidate resources.

[0212] In order to determine the start of the time domain resources, the UE may be informed of the time offset value. For example, the time offset value field may be carried by the scheduling DCI to indicate the number of time units between the scheduling DCI and the scheduled time domain resources for multicast sidelink transmission. The time unit may be a subframe, a time slot, a mini-time slot, or a symbol. Or the UE may be indicated with a two-level time offset to determine the starting point of the time domain resources. For example, the UE may be indicated with a time slot / subframe offset to determine which time slot / subframe the time domain resources start from. Then, the UE may be indicated with the index of the starting symbol / mini-time slot to determine the starting point within the time slot / subframe.

[0213] To determine the duration of the time domain resources, the length of the bitmap or duration may be indicated by the scheduling DCI. In an example, the UE may be informed of the bitmap. The bitmap may indicate which time resources within the candidate resources configured by the RRC are used for the multicast sidelink transmission. In another example, the UE may be informed of the length of the time domain resources, for example, 1. The UE may then use 1 consecutive resource units within the candidate resources configured by the RRC for the multicast sidelink transmission. The resource unit may be a subframe, a time slot, a mini-time slot, or a symbol.

[0214] The fields for indicating the start and duration of the time domain resource may also be notified through a DCI field. For example, a predefined or preconfigured table may contain combinations of the start and duration of the time domain resource, each combination being associated with an index. The UE may be notified of an index through a DCI field by the scheduling DCI. The UE determines the time domain resource by finding the corresponding start and duration values ​​from the table.

[0215] Alternative 2 - Time Domain Resource Assignment: The UE may be configured with candidate resources without RRC configuration. The UE may be dynamically indicated the time domain resources for multicast sidelink transmission through scheduling DCI. DCI may carry information of time domain resources, such as time slot / subframe offset, starting point, duration, etc. The above parameters may be indicated by different DCI fields, or may be indicated by DCI fields together. For example, the time domain resources may be dynamically notified only through the scheduling DCI through the time slot / subframe offset value and SLV.

[0216] For multicast sidelink transmission, the UE may, for example, transmit the same information in multiple directions via k beams. The UE may be indicated a time domain resource, and the time domain resources used for all beams may be determined by some predefined rules. For example, the UE may be indicated mini-slot n, and the UE may use mini-slot n for the first beam, and use the next k-1 mini-slots of the configured candidate time resources for the remaining beams. Or the UE may be indicated the time domain resources used for each beam separately. For example, the UE may be indicated k start and duration values ​​of the time domain resources. Or the UE may be indicated the gap between the time domain resources used for transmission in the first direction and for transmission in the remaining directions.

[0217] For multicast sidelink transmission, the scheduling DCI may indicate the time domain resources for both PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be jointly allocated by the scheduling DCI, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Or the time domain resources for PSCCH or PSSCH may be allocated separately by the scheduling DCI. For example, the scheduling DCI may allocate two time domain resources for PSCCH or PSSCH, respectively.

[0218] Retransmission field. HARQ feedback may be introduced on the multicast sidelink. The transmitter UE 202 may multicast messages to multiple receiver UEs via multiple beams, where each beam may cover one or more UEs. Retransmission may be triggered per beam. For a beam, a retransmission may be triggered if any UE under the beam is NACKed, or if all UEs under the beam are NACKed.

[0219] The retransmission at the transmitter UE 202 may be triggered by the receiver UE 203, or may be triggered by the gNB 201. According to an alternative, the receiver UE may feed back a NACK to the gNB 201. The gNB 201 may trigger the transmitter UE 202 to perform the retransmission by sending another scheduling DCI for the retransmission. For the retransmission, the gNB 201 may instruct the transmitter UE 202 to use the same MCS; or the gNB 201 may instruct the transmitter UE 202 to use a different MCS. If repetition is performed, the UE may also be notified of a different RV for the repetition of the retransmission. In this case, the retransmission field may be one bit to indicate whether the scheduling is for an initial transmission or for a retransmission. For example, "0" indicates that the transmission is an initial transmission, and "1" indicates that the transmission is a retransmission. A bitmap may be notified in the scheduling DCI to indicate which beams need to be retransmitted, for example, {b k-1 ,…,b1,b0} is mapped, b k-1 is mapped to the first beam and b0 is mapped to the kth beam. An exemplary call flow is shown in Figure 6 middle.

[0220] Figure 6 An exemplary call flow for gNB 201 triggered retransmission for multicast sidelink is shown. In step 241a, Tx UE 202 obtains (e.g., receives) scheduling DCI for initial transmission via Uu interface. In step 241b, Rx UE 203 obtains scheduling DCI for initial transmission via Uu interface. In step 242a, Rx UE 203 obtains multicast transmission on beam 1 on the sidelink. In step 242b, Rx UE 203 obtains multicast transmission on beam 2 on the sidelink. In step 242c, Rx UE 203 obtains multicast transmission on beam k on the sidelink. Based on steps 242a to 242c, steps 243a to 243c may be performed. In step 243a, Rx UE 203 sends HARQ feedback from UE 1…UE i1 on beam 1 to gNB 201 via Uu interface. In step 243b, Rx UE 203 sends HARQ feedback from UE i1+1…UE i2 on beam 2 to gNB 201 via the Uu interface. In step 243c, Rx UE 203 sends HARQ feedback from UE i1+1…UE i2 on beam k to gNB 201 via the Uu interface. k-1 +1…UE i kHARQ feedback is sent to gNB 201. If NACK is received for, for example, beam 1 and beam 4, steps 244a to 246b may be performed. In step 244a, a scheduling DCI for retransmissions on beam 1 and beam 4 may be sent to Tx UE 202 over the Uu interface. In step 244b, a scheduling DCI for retransmissions on beam 1 and beam 4 may be sent to Rx UE 203 over the Uu interface. In step 245a, multicast retransmissions on beam 1 on the side link are obtained. In step 245b, Rx UE 203 obtains multicast retransmissions on beam 4 on the side link. Based on steps 245a to 245b, steps 246a to 246c may be performed. In step 246a, Rx UE 203 sends HARQ feedback from UE 1...UE i1 on beam 1 to gNB 201 over the Uu interface. In step 246b, Rx UE 203 sends HARQ feedback from UE i3+1…UE i4 to gNB 201 on beam 4 via the Uu interface.

[0221] According to another alternative, the receiver UE may feedback NACK to the transmitter UE 202. For each beam, the transmitter UE 202 may determine whether to perform retransmission based on the feedback. For retransmission, the transmitter UE 202 may choose to use the same MCS as used for the initial transmission; or the transmitter UE 202 may autonomously choose to use a different MCS.

[0222] Resources for retransmission may be pre-reserved by a retransmission field in a scheduling DCI carrying a grant for initial transmission. Assuming k beams are used for multicast transmission, similar to the resource allocation for initial transmission, the retransmission field may indicate k time or frequency resources for retransmission, or the retransmission field may indicate one time or frequency resource and the transmitter UE 202 determines the resources for the remaining beams by some predefined rules, for example, using the next k-1 time resource units among the candidate time resources. The allocation of retransmission may be indicated by a time resource, such as a symbol index, a mini-slot index, an RB index, etc. Or the allocation of retransmission may be indicated by a time or frequency offset between the retransmission and the initial transmission, such as a symbol offset, a mini-slot offset, an RB offset, etc. If retransmission is triggered on any beam, the transmitter UE 202 may use the corresponding pre-reserved resources for retransmission on that beam. An exemplary call flow is shown in Figure 7 middle.

[0223] Figure 7An exemplary call flow for Rx UE 203 triggered retransmission for multicast sidelink is shown. In step 231a, Tx UE 202 obtains (e.g., receives) scheduling DCI for initial transmission and retransmission over the Uu interface. In step 231b, Rx UE 203 obtains scheduling DCI for initial transmission and retransmission over the Uu interface. In step 232a, Rx UE 203 obtains multicast transmission on beam 1 on the sidelink. In step 232b, Rx UE 203 obtains multicast transmission on beam 2 on the sidelink. In step 232c, Rx UE 203 obtains multicast transmission on beam k on the sidelink. Based on steps 232a to 232c (which may be received from Tx UE 202), steps 233a to 233c may be performed and sent to Tx UE 202 (or in an alternative implementation, to gNB 201). In step 233a, Rx UE 203 sends HARQ feedback on the side link from UE 1…UE i1 on beam 1 to Tx UE 202. Communication between Tx UE and Rx UE occurs on the side link. Communication between vehicle UE (e.g., Tx UE or Rx UE) and gNB occurs on the Uu interface. In step 233b, Rx UE 203 sends HARQ feedback on the side link from UE i1+1…UE i2 on beam 2 to Tx UE 202. In step 233c, Rx UE 203 sends HARQ feedback on the side link from UE i1+1…UE i2 on beam k to Tx UE 202. k-1 +1…UE i k HARQ feedback is sent to Tx UE 202. If NACK is received for, for example, beam 1 and beam 3, steps 234a to 235b may be performed. In step 234a, RX UE 203 obtains multicast retransmissions on beam 1 on the side link. In step 234b, Rx UE 203 obtains multicast retransmissions on beam 3 on the side link. Based on steps 234a to 234b, steps 235a to 236b may be performed. In step 235a, Rx UE 203 sends HARQ feedback from UE 1 ... UE i1 on beam 1 to Tx UE 202 on the side link. In step 235b, Rx UE 203 sends HARQ feedback from UE i2+1 ... UE i3 on beam 3 on the side link to Tx UE 202.

[0224] HARQ field. The scheduling DCI may indicate the HARQ ID or HARQ process number to the transmitter UE 202 and the receiver UE 203. The scheduling DCI may also indicate resource allocation for HARQ feedback. The resources for HARQ feedback for different beams may be TDM, and the resources for HARQ feedback for different UEs on the same beam may be FDM. The scheduling DCI may indicate the time or frequency resources for HARQ feedback, such as symbol index, mini-slot index, RB index, etc. Or the scheduling DCI may indicate the time or frequency offset between the HARQ feedback and the initial transmission, such as symbol offset, mini-slot offset, RB offset, etc. If the retransmission is triggered by the receiver UE 203, the receiver UE 203 may send the HARQ feedback to the transmitter UE 202 using the allocated HARQ feedback resources. If the retransmission is triggered by the gNB 201, the receiver UE 203 may send the HARQ feedback to the gNB 201 using the allocated HARQ feedback resources.

[0225] Beam scanning information field. The scheduling DCI may indicate the number of beam scans that the UE needs to perform. The UE may be dynamically informed of the value of the number of beam scans through the scheduling DCI. Or the RRC may configure multiple potential values ​​for the number of beam scans, where each value is associated with an index. The UE may be informed of an index and determine the value of the number of beam scans. The beam used for beam scanning may be indicated by the gNB 201. Or the beam used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0226] Frequency domain resource allocation field. In order to determine the frequency domain resources for multicast sidelink transmission, the UE may be indicated information about the lowest RB, RBG or subchannel to be used. The UE may be informed of the index of the lowest RB or RBG. Or the UE may be informed of the offset between the lowest RB, RBG or subchannel of the frequency domain resource allocation and the lowest RB, RBG or subchannel of the candidate frequency domain resources configured by RRC. The offset may be an RB or RBG.

[0227] To determine the range of the frequency domain resources, the width of the bitmap or frequency domain resources may be indicated by the scheduling DCI. For one example, the UE may be informed of the bitmap. The bitmap may indicate which frequency resources within the candidate frequency resources configured by the RRC are used for the multicast sidelink transmission. For another example, the UE may be informed of the width of the frequency domain resources, for example, w. The UE may then use w consecutive RBs, RBGs, or subchannels for the multicast sidelink transmission.

[0228] For multicast sidelink transmission, the UE may send the same information in multiple directions. The UE may be instructed to use one frequency domain resource for transmission in all directions. Alternatively, the UE may be informed of different frequency domain resources for transmission in different directions.

[0229] For multicast sidelink transmission, the scheduling DCI may indicate frequency domain resources for both PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be jointly allocated by the scheduling DCI, for example, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Or the frequency domain resources for PSCCH or PSSCH may be allocated separately by the scheduling DCI. For example, the scheduling DCI may allocate two frequency domain resources for PSCCH or PSSCH, respectively.

[0230] Slot Format Indicator Field. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0231] If there is a conflict between the candidate time resources configured by RRC and the SFI notified by DCI, the DCI may rewrite the RRC configuration. The UE may skip the conflicting symbols and not perform side link transmission on them. For example, assume that symbol k in time slot m is configured as a candidate time resource in the RRC configuration. If symbol k in time slot m is marked as "D" in the SFI, the UE may not regard symbol k in time slot m as a candidate time resource. When the UE determines the time resources for multicast side link transmission, the UE may skip symbol k in time slot m. If the candidate time resource is in a mini-slot and there is a conflict for a portion of the symbols in the mini-slot, the UE may skip the entire mini-slot and not perform side link transmission on it. Or the UE may only skip the conflicting symbols and perform side link transmission on non-conflicting symbols within the mini-slot.

[0232] The symbols used for sidelink communication may be further divided into symbols for sidelink transmission and symbols for sidelink reception. We disclose that labels "ST" and "SR" may be introduced for time slot format. For transmitter UE202, the UE may use symbols marked as "ST" by the SFI for sidelink transmission, and may use symbols marked as "SR" by the SFI for receiving feedback, such as HARQ feedback. For receiver UE 203, the UE may use symbols marked as "ST" by the SFI for receiving sidelink transmission, and may use symbols marked as "SR" by the SFI for sending feedback, such as HARQ feedback.

[0233] Dynamic resource allocation for unicast and multicast

[0234] Dynamic resource allocation for unicast and multicast - general signaling design and UE behavior for unicast or multicast use cases: The subject matter disclosed here for dynamic resource allocation (e.g. Figure 10-Figure 16 and associated description) can be used for unicast or multicast. In NR V2X Mode 1, gNB 201 can dynamically schedule unicast or multicast transmission on the sidelink through scheduling grants. For unicast or multicast, Tx UE 202 or Rx UE 203 should know the resources for transmission and reception. The transmission schedule can be indicated by a scheduling DCI sent on the Uu interface, which has the following example.

[0235] Scheduling DCI sent on Uu interface Example 1: gNB 201 may send scheduling DCI to Tx UE 202 or Rx UE 203. Shared resources may be used to send scheduling DCI for Tx UE 202 or Rx UE 203, for example, by SDM. In this case, the UE may be configured with one CORESET for monitoring scheduling DCI for Tx UE 202 or Rx UE 203. Alternatively, dedicated resources may be used to send scheduling DCI for Tx UE 202 and Rx UE 203, for example, by TDM or by FDM. In this case, the UE may be configured with one CORESET or two different CORESETs for monitoring scheduling DCI for Tx UE 202 or scheduling DCI for Rx UE 203.

[0236] Scheduling DCI sent on Uu interface Example 2: gNB 201 may send scheduling DCI only to Tx UE 202. By decoding the scheduling DCI, Tx UE 202 may determine the scheduled grant for feedback in the received DCI. Tx UE 202 may then indicate the received sidelink transmission schedule to Rx UE 203 using SCI. For example, resource allocation for PSSCH (e.g., for data transmission or for sending reference signals for measurement) and resource allocation feedback (e.g., HARQ feedback or CSI feedback). Rx UE 203 may be configured with a monitoring opportunity for monitoring SCI. By decoding SCI, Rx UE 203 may determine the resources for PSSCH and feedback.

[0237] When gNB 201 sends scheduling DCI to Tx UE 202 and Rx UE 203, gNB 201 may schedule sidelink communications through the following example:

[0238] Scheduling DCI for both - Scheduling side link communication Example 1: gNB 201 can send scheduling DCI to Tx UE 202 or Rx UE 203, where HARQ feedback is sent from Rx UE 203 to gNB 201 via Uu interface. Fig.10 Example showing unicast usage.

[0239] The scheduling DCI may carry time and frequency resource assignments for sidelink transmissions, for example, resource assignments for SCI and PSSCH, so that either the Tx UE 202 or the Rx UE 203 may know the resources for sending or receiving data on the sidelink.

[0240] The scheduling DCI may carry information about resources used for HARQ feedback. The resources used for HARQ may be explicitly indicated by the scheduling DCI, for example, indicating time and frequency resources; or may be implicitly indicated by the scheduling DCI, for example, an index of a HARQ feedback resource configuration configured through RRC. For a UE scheduled to transmit on the sidelink, the UE may ignore the resource allocation for HARQ feedback. For a UE scheduled to receive on the sidelink, the UE may send HARQ feedback to gNB201 using the allocated resources via the Uu interface.

[0241] Scheduling DCI for both - Scheduling side link communication Example 2: gNB 201 may send scheduling DCI to both Tx UE 202 and Rx UE 203, where HARQ feedback is sent from Rx UE 203 to Tx UE 202 via the side link. Fig.11 Example showing unicast usage.

[0242] The scheduling DCI may carry time and frequency resource assignments for sidelink transmissions, for example, resource assignments for SCI and PSSCH, so that the Tx UE 202 or Rx UE 203 may know the resources for sending or receiving data on the sidelink.

[0243] The scheduling DCI may carry information about resources used for HARQ feedback. The resources used for HARQ may be explicitly indicated by the scheduling DCI, for example, indicating time and frequency resources; or may be implicitly indicated by the scheduling DCI, for example, an index of a HARQ feedback resource configuration configured through RRC. For a UE scheduled to receive on the sidelink, the UE may send HARQ feedback to the Tx UE 202 using the assigned resources on the sidelink. For a UE scheduled to send on the sidelink, the UE may monitor or receive HARQ feedback in the assigned resources.

[0244] Scheduling DCI for both - Scheduling side link communication Example 3: gNB 201 can send scheduling DCI to both Tx UE 202 and Rx UE 203, where HARQ feedback is first sent from Rx UE 203 to Tx UE 202 on the side link, and then Tx UE 202 can feed back the received information to gNB 201 via the Uu interface. Fig.12 Example showing unicast usage.

[0245] Tx UE 202 may forward all received HARQ feedback to gNB 201. Alternatively, in order to reduce overhead, Tx UE 202 may feed back compact information to gNB 201.

[0246] The scheduling DCI may carry time and frequency resource assignments for sidelink transmissions, for example, resource assignments for SCI and PSSCH, so that the Tx UE 202 or Rx UE 203 may know the resources for sending or receiving data on the sidelink.

[0247] The scheduling DCI may carry information about resources used for HARQ feedback. The resources used for HARQ may be explicitly indicated by the scheduling DCI, for example, indicating time or frequency resources; or may be implicitly indicated by the scheduling DCI, for example, an index of a HARQ feedback resource configuration configured through RRC. For a UE scheduled to receive on the sidelink, the UE may send HARQ feedback to the Tx UE 202 using the assigned resources on the sidelink. For a UE scheduled to send on the sidelink, the UE may monitor or receive HARQ feedback in the assigned resources.

[0248] The scheduling DCI may carry time and frequency resource assignments for feedback from Tx UE 202 to gNB 201. For a UE scheduled to receive on the sidelink, the UE may ignore the resource assignments for feedback from Tx UE 202 to gNB 201. For a UE scheduled to transmit on the sidelink, the UE may send feedback to gNB 201 using the assigned resources over the Uu interface.

[0249] When gNB 201 sends scheduling DCI to Tx UE 202 and Rx UE 203, the same DCI format may be used for Tx UE 202 and Rx UE 203, for example, the scheduling DCI for Tx UE 202 and Rx UE 203 may carry the same DCI field. For example, the DCI for Tx UE 202 and Rx UE 203 may be scrambled with the same RNTI, for example, SLUnicast-RNTI, SLGroupcast-RNTI. The UE may check the transmit / receive indicator field in the DCI to determine whether it is scheduled to be used as Tx UE 202 or as Rx UE 203.

[0250] Alternatively, the scheduling DCI for Tx UE 202 or Rx UE 203 may be sent in different DCI formats, for example, the scheduling DCI for Tx UE 202 or Rx UE 203 may carry different DCI fields. For example, the DCI for Tx UE 202 or Rx UE 203 may be scrambled using different RNTIs. The UE may be configured with two RNTIs for unicast and groupcast, for example, SLUnicastTx-RNTI or SLUnicastRx-RNTI; or SLGroupcastTx-RNTI or SLGroupcastRx-RNTI. If the UE detects that the DCI is scrambled using SLUnicastTx-RNTI or SLGroupcastTx-RNTI, the UE may determine that it is scheduled for transmission on the side link. If the UE detects that the DCI is scrambled using SLUnicastRx-RNTI or SLGroupcastRx-RNTI, the UE may determine that it is scheduled for reception on the side link.

[0251] When gNB 201 sends scheduling DCI only to Tx UE 202, gNB 201 may schedule sidelink communication by the following example:

[0252] Scheduling DCI for one party only - Scheduling side link communication Example 1: gNB 201 may send scheduling DCI only to Tx UE 202, where HARQ feedback is sent from Rx UE 203 to gNB 201 via Uu interface. Fig.13 Example showing unicast usage.

[0253] The scheduling DCI may carry time and frequency resource assignments for sidelink transmissions, such as resource assignments for SCI and PSSCH. Tx UE 202 indicates resource assignments to Rx UE 203 via SCI. Therefore, both Tx UE 202 and Rx UE 203 may know the resources for sending and receiving data on the sidelink.

[0254] The scheduling DCI may carry information about resources used for HARQ feedback. The resources used for HARQ may be explicitly indicated by the scheduling DCI, for example, indicating time and frequency resources; or may be implicitly indicated by the scheduling DCI, for example, an index of a HARQ feedback resource configuration configured through RRC. The Tx UE 202 may indicate resource allocation to the Rx UE 203 through the SCI. For a UE scheduled to transmit on the sidelink, the UE may ignore the resource allocation for HARQ feedback. For a UE scheduled to receive on the sidelink, the UE may send HARQ feedback to the gNB 201 using the allocated resources through the Uu interface.

[0255] Scheduling DCI for one party only - Scheduling side link communication Example 2: gNB 201 may send scheduling DCI only to Tx UE 202, where HARQ feedback is sent from Rx UE 203 to Tx UE 202 on the side link. Fig.14 Example showing unicast usage.

[0256] The scheduling DCI may carry time and frequency resource assignments for sidelink transmissions, such as resource assignments for SCI and PSSCH. Tx UE 202 indicates resource assignments to Rx UE 203 via SCI. Therefore, both Tx UE 202 and Rx UE 203 may know the resources used to send and receive data on the sidelink.

[0257] The scheduling DCI may carry information about resources used for HARQ feedback. The resources used for HARQ may be explicitly indicated by the scheduling DCI, for example, indicating time and frequency resources; or may be implicitly indicated by the scheduling DCI, for example, an index of a HARQ feedback resource configuration configured through RRC. The Tx UE 202 indicates resource allocation to the Rx UE 203 through the SCI. For a UE scheduled to receive on the sidelink, the UE may send HARQ feedback to the Tx UE 202 using the allocated resources on the sidelink. For a UE scheduled to send on the sidelink, the UE may monitor or receive HARQ feedback in the allocated resources.

[0258] Scheduling DCI for one party only - Scheduling side link communication Example 3: gNB 201 may send scheduling DCI only to Tx UE 202, where HARQ feedback is first sent from Rx UE 203 to Tx UE 202 on the side link, and then Tx UE 202 feeds back the received information to gNB 201 through the Uu interface.

[0259] Fig.15A Examples showing usage. Fig. 15B25 shows an exemplary method flow. In summary, as described in more detail below, at step 251, the scheduling DCI may be obtained by Tx UE 202. At step 252, Tx UE 202 may perform transmission to Rx UE 203 via a side link. At step 253, based on step 252, Tx UE 202 may receive feedback from Rx UE 203. As provided in more detail herein, with respect to FIG. 15 and other figures (e.g., Figure 20-22 or Figure 6-Figure 7 etc.), there may be different scheduling and other schemes associated with scheduling DCI.

[0260] Tx UE 202 may send (e.g., forward) all received HARQ feedback to gNB 201. Alternatively, to reduce overhead, Tx UE 202 may feed back compact information. Scheduling DCI may carry time and frequency resource assignments for sidelink transmission, for example, resource assignments for SCI and PSSCH. Tx UE 202 indicates resource assignments to Rx UE 203 via SCI. Therefore, either Tx UE 202 or Rx UE 203 may know the resources used to send and receive data on the sidelink.

[0261] The scheduling DCI may carry information of resources for HARQ feedback sent from the Rx UE 203 to the Tx UE 202. The resources used for HARQ may be explicitly indicated by the scheduling DCI, for example, indicating time and frequency resources; or may be implicitly indicated by the scheduling DCI, for example, an index of a HARQ feedback resource configuration configured through RRC. The Tx UE 202 indicates resource allocation to the Rx UE 203 through the SCI. For a UE scheduled to receive on the sidelink, the UE may send HARQ feedback to the Tx UE 202 on the sidelink using the allocated resources. For a UE scheduled to send on the sidelink, the UE may monitor or receive HARQ feedback in the allocated resources. For example, the scheduling DCI may carry one DCI field indicating resources for sending HARQ feedback from Rx UE 203 to Tx UE 202, such as a PSFCH resource indicator field, where each value may be associated with an indexed PSFCH resource configured through RRC configuration or predefined in the specification.

[0262] The UE may be configured with a common PSFCH resource configuration or a dedicated PSFCH resource configuration for sending HARQ feedback from the Rx UE 203 to the Tx UE 202 on the sidelink. For example, the UE may be configured with a common RRC configuration psfch-ResourceCommon through broadcast signaling (e.g., through RMSI or OSI); or the UE may be configured with a dedicated RRC configuration PSFCH-ResourceSet. The PSFCH-ResourceSet may include one or more RRC configuration PSFCH-Resources, where an example of an RRC configuration PSFCH-Resource is shown in Fig.19 middle.

[0263] For the case where only one of the common configuration and the dedicated configuration is supported, when the UE receives the scheduling DCI and decodes the PSFCH resource indicator field, the UE can determine the corresponding PSFCH resource through the configured psfch-ResourceCommon or the configured PSFCH-ResourceSet.

[0264] For the case where both public configuration and dedicated configuration are supported, when the UE receives the scheduling DCI and decodes the PSFCH resource indicator field, the UE can determine the corresponding PSFCH resources through the dedicated RRC configuration PSFCH-ResourceSet; or if the dedicated RRC configuration is not configured, the corresponding PSFCH resources are determined through the public RRC configuration psfch-ResourceCommon.

[0265] For another example, the scheduling DCI may carry one DCI field indicating the timing for sending HARQ feedback from the Rx UE 203 to the Tx UE 202, for example, a SL HARQ timing indicator field.

[0266] In one aspect, the indicated timing may be a time offset between the scheduled initial transmission and HARQ feedback (from Rx UE 203 to Tx UE 202) on the sidelink. For example, the UE may be configured with a candidate time offset via RRC through an RRC parameter sl-InitalDataToSL-ACK having content '(SEQUENCE(SIZE(8))OF INTEGER(0..15))', where the time offset may be a slot, a mini-slot, or a symbol. When the UE receives the scheduling DCI and decodes the SL HARQ timing indicator field, the UE may determine the time offset by finding the corresponding entry in the configured RRC parameter sl-InitalDataToSL-ACK.

[0267] In another approach, the indicated timing may be a time offset between the HARQ feedback (from the Rx UE 203 to the Tx UE 202) and the last repetition / retransmission (in other words, repetition or retransmission) scheduled for a transport block (TB) on the sidelink. Assuming k repetitions / retransmissions are scheduled by a scheduling DCI, the SL HARQ timing indicator field indicates the time offset between the HARQ feedback and the scheduled kth repetition / retransmission. If no repetitions are scheduled, e.g., k=0, the SL HARQ timing indicator field indicates the time offset between the HARQ feedback and the scheduled initial transmission. For example, the UE may be configured with a candidate time offset via RRC through an RRC parameter sl-LastDataToSL-ACK having the content 'SEQUENCE(SIZE(8))OF INTEGER(0..15)', where the time offset may be a slot, a minislot, or a symbol. When the UE receives the scheduling DCI or decodes the UL HARQ timing indicator field, the UE can determine the time offset by finding the corresponding entry in the configured RRC parameter sl-LastDataToSL-ACK.

[0268] The scheduling DCI may carry time and frequency resource assignments for feedback from the Tx UE 202 to the gNB 201. The Tx UE 202 may not indicate the resource assignments to the Rx UE 203 via the SCI. For a UE scheduled to transmit on the sidelink, the UE may send feedback to the gNB 201 using the assigned resources via the Uu interface. For example, the scheduling DCI may carry one DCI field indicating resources for sending HARQ feedback from a V2X UE (e.g., Tx UE 202) to the gNB 201, e.g., a PUCCH resource indicator field, where each value is associated with an indexed PUCCH resource configured via RRC configuration or predefined in the specification.

[0269] The UE may be configured with a common PUCCH resource configuration or a dedicated PUCCH resource configuration for the transmission of HARQ information for downlink transmission on the Uu interface. The UE may use the same set of common or dedicated configurations for the transmission of HARQ information on the Uu interface for the sidelink transmission on the sidelink. For example, when the UE receives a scheduling DCI or decodes the PUCCH resource indicator field, the UE may determine the corresponding PUCCH resource through the dedicated RRC configuration PUCCH-ResourceSet in PUCCH-Config or through the common RRC configuration pucch-ResourceCommon in SIB1 (if the dedicated RRC configuration is not configured).

[0270] Alternatively, the UE may be configured with a different set of common or dedicated configurations for the transmission of HARQ information on the Uu interface for the sidelink transmission on the sidelink. For example, the UE may be configured with a common RRC configuration pucch-sl-ResourceCommon via broadcast signaling (e.g., via RMSI or OSI); or the UE may be configured with a dedicated RRC configuration SL-PUCCH-ResourceSet.

[0271] For the case where only one of the common configuration and the dedicated configuration is supported, when the UE receives the scheduling DCI and decodes the PUCCH resource indicator field, the UE can determine the corresponding PUCCH resources through the configured pucch-sl-ResourceCommon or the configured SL-PUCCH-ResourceSet.

[0272] For the case where both public configuration and dedicated configuration are supported, when the UE receives the scheduling DCI or decodes the PUCCH resource indicator field, the UE can determine the corresponding PUCCH resources through the dedicated RRC configuration SL-PUCCH-ResourceSet; or if the dedicated RRC configuration is not configured, the corresponding PUCCH resources are determined through the public RRC configuration pucch-sl-ResourceCommon.

[0273] For another example, the scheduling DCI may carry a DCI field indicating the timing for sending HARQ feedback from the V2X UE (e.g., Tx UE 202) to the gNB 201, e.g., a UL HARQ timing indicator field.

[0274] In one aspect, the indicated timing may be the time offset between the HARQ feedback (from the V2X UE to the gNB 201) and the scheduled initial transmission on the sidelink. For example, the UE may be configured with a candidate time offset via RRC through an RRC parameter sl-InitalDataToUL-ACK having content 'SEQUENCE(SIZE(8))OFINTEGER(0..15)', where the time offset may be a slot, a mini-slot, or a symbol. When the UE receives the scheduling DCI and decodes the UL HARQ Timing Indicator field, the UE may determine the time offset by finding the corresponding entry in the configured RRC parameter sl-InitalDataToUL-ACK.

[0275] In a second approach, the indicated timing may be a time offset between the HARQ feedback (from the V2X UE to the gNB 201) and the scheduled HARQ feedback sent on the sidelink (from the Rx UE 203 to the Tx UE 202). For example, the UE may be configured with a candidate time offset via RRC through an RRC parameter sl-ACKToUL-ACK having the content 'SEQUENCE(SIZE(8))OF INTEGER(0..15)', where the time offset may be a slot, a mini-slot, or a symbol. When the UE receives the scheduling DCI or decodes the UL HARQ timing indicator field, the UE may determine the time offset by finding the corresponding entry in the configured RRC parameter sl-ACKToUL-ACK.

[0276] In a third approach, the indicated timing may be the time offset between the HARQ feedback (from the V2X UE to the gNB 201) and the last repetition / retransmission of the scheduled transmission for the TB on the sidelink. Assuming k repetitions / retransmissions are scheduled by a scheduling DCI, the UL HARQ Timing Indicator field indicates the time offset between the HARQ feedback and the scheduled kth repetition / retransmission. If no repetitions are scheduled, e.g., k=0, the UL HARQ Timing Indicator field indicates the time offset between the HARQ feedback and the scheduled initial transmission. For example, the UE may be configured with a candidate time offset via RRC through an RRC parameter sl-LastDataToUL-ACK having the content 'SEQUENCE(SIZE(8))OF INTEGER(0..15)', where the time offset may be a slot, a minislot, or a symbol. When the UE receives the scheduling DCI and decodes the UL HARQ timing indicator field, the UE can determine the time offset by finding the corresponding entry in the configured RRC parameter sl-LastDataToUL-ACK.

[0277] When the gNB uses dynamic scheduling to grant scheduling of sidelink transmissions, gNB 201 can use one DCI to schedule multiple retransmissions / repetitions of a TB as well as the scheduling of the initial transmission of the TB.

[0278] When gNB 201 dynamically schedules the sidelink transmission of a TB using DCI, gNB 201 may schedule one or more retransmissions / repetitions of the TB using the same scheduling DCI. Retransmissions or HARQ feedback may be performed by Tx UE 202 or Rx UE 203 in the following manners: 1) DCI-scheduled blind retransmissions on the sidelink; 2) DCI-scheduled retransmissions based on HARQ feedback on the sidelink; or 3) DCI-scheduled retransmissions based on HARQ feedback, early termination sent on the Uu interface, etc.

[0279] Blind retransmission of DCI schedule on sidelink

[0280] DCI-Scheduled Blind Retransmissions on Sidelink: In one case, after receiving the scheduling DCI, the Tx UE 202 may blindly send all scheduled transmissions. For example, the Tx UE 202 may perform all scheduled initial transmissions and retransmissions / repetitions regardless of whether the Rx UE 203 successfully decodes the data. In this case, a HARQ feedback resource allocation may be scheduled by DCI on the sidelink for the Rx UE 203 to send HARQ feedback to the Tx UE 202; and a HARQ feedback resource allocation may be scheduled by DCI on the Uu interface for the Tx UE 202 to send HARQ feedback to the gNB 201. An example is shown in Fig. 20 In the example, the DCI is scheduled to be initially transmitted in slot 0 and retransmitted twice in slot 1 and slot 2. The transmission of SCI is scheduled in slot 0; the transmission of HARQ feedback from Rx UE 203 to Tx UE 202 is scheduled in slot 2; and the transmission of HARQ feedback from Tx UE 202 to gNB 201 is scheduled in slot 3.

[0281] In the example shown in the figure, the initial transmission and retransmission are scheduled in consecutive time slots. In another example, the initial transmission and retransmission may be scheduled in non-consecutive time slots, for example, the initial transmission may be scheduled in time slot 0, and two retransmissions may be scheduled in time slot 2 and time slot 4, respectively.

[0282] The Rx UE 203 may determine the scheduled initial transmission and retransmission by decoding the SCI. If the Rx UE 203 fails to receive the sidelink transmission after all repetitions, the Rx UE 203 may use the scheduled HARQ feedback resources (eg, Fig. 202 (HARQ feedback resources in slot 2 in 100M) to Tx UE 202. If Rx UE 203 successfully receives the side link transmission, Rx UE 203 may send ACK to Tx UE 202 using the scheduled HARQ feedback resources, or Rx UE 203 may not send anything on the scheduled HARQ feedback resources to Tx UE 202. If Rx UE 203 successfully receives the side link transmission before all scheduled retransmissions, for example, Rx UE 203 successfully receives the side link transmission after the initial transmission or after the first retransmission, Rx UE 203 may skip the remaining scheduled retransmissions and do not attempt to decode the PSSCH.

[0283] After the Tx UE 202 receives the HARQ feedback (eg, ACK or NACK) from the Rx UE 203, the Tx UE 202 may use the scheduled HARQ feedback resources (eg, Fig. 20 The HARQ feedback resource in time slot 3 in time slot 1 is used to send HARQ feedback to gNB 201.

[0284] HARQ feedback based retransmission of DCI scheduling on sidelink

[0285] DCI scheduled retransmissions based on HARQ feedback on the sidelink: In another case, the scheduled DCI may schedule retransmissions based on HARQ feedback on the sidelink. An example is shown in Fig.21 , where the scheduling DCI schedules the initial transmission in slot 0 and schedules two retransmissions in slot 1 and slot 2, respectively. The scheduling DCI schedules the transmission of HARQ feedback from Rx UE 203 to Tx UE 202 associated with the initial transmission and two retransmissions in slot 0, slot 1, and slot 2, respectively. The transmission of SCI is scheduled in slot 0; the transmission of HARQ feedback from Tx UE 202 to gNB 201 is scheduled in slot 3.

[0286] In the example shown in the figure, the sidelink transmission and the associated HARQ feedback on the sidelink are scheduled in the same time slot. In another example, the sidelink transmission and the associated HARQ feedback may be scheduled in different time slots, for example, the transmission of HARQ feedback from Rx UE 203 to Tx UE 202 may be scheduled in time slot 1, time slot 2, and time slot 3, respectively. The initial transmission and retransmission may be as follows. Fig. 20As shown in , it is scheduled in continuous time slots, or it can also be scheduled in non-continuous time slots, for example, the initial transmission and the associated HARQ feedback are scheduled in time slot 0 and time slot 1, respectively; the first retransmission and the associated HARQ feedback are scheduled in time slot 2 and time slot 3, respectively; the second retransmission and the associated HARQ feedback are scheduled in time slot 4 and time slot 5, respectively, and so on.

[0287] Rx UE 203 may determine the scheduled initial transmission and retransmission by decoding the SCI. For each transmission, Rx UE 203 may send HARQ feedback (e.g., ACK / NACK-based feedback or NACK-only-based feedback) to Tx UE 202 using the associated HARQ feedback resources. Tx UE 202 may perform scheduled retransmissions for TBs until Rx UE 203 successfully receives the TBs. If Tx UE 202 receives NACK on all HARQ feedbacks on the side link, the side link transmission fails. Tx UE 202 may send NACK to gNB 201 using the scheduled HARQ feedback resources on the Uu interface. If the scheduled side link transmission is successful, Tx UE 202 may send ACK to gNB 201 using the scheduled HARQ feedback resources.

[0288] If a scheduled sidelink transmission for a TB (eg, TB 1) succeeds before all scheduled retransmissions are performed, the Tx UE 202 may transmit another TB (eg, TB 2) using the resources used for the remaining retransmissions. Fig.21 In the example shown in FIG. 2 , if the transmission of TB 1 is successful in slot 0, Tx may transmit TB 2 using the scheduled resources in slot 1 and slot 2. For Rx UE 203, after successfully receiving the scheduled TB, Rx UE 203 may continue to monitor and decode the PSSCH transmitted on the resources for the remaining retransmissions; and send feedback to TxUE 202 using the associated feedback resources. Tx UE 202 may send HARQ feedback to gNB 201 based on the transmission results for the scheduled TB. For example, if the transmission of TB 1 is successful in slot 0, and the transmission of TB 2 in slot 1 and slot 2 fails, Tx UE 202 may still send ACK to gNB 201 using the resources in slot 3.

[0289] In another approach, if a scheduled sidelink transmission succeeds before all scheduled retransmissions are performed, the unused resources (e.g., resources scheduled for retransmissions on the sidelink and associated HARQ feedback) may be released. The Tx UE 202 may not transmit data during the remaining scheduled retransmissions. The Rx UE 203 may skip decoding the remaining scheduled retransmissions and not send feedback on the associated resources. Once the resources are released, the Mode 2 V2X UE may schedule a sidelink transmission on the released resources.

[0290] The scheduling DCI may indicate multiple HARQ feedback resources on the side link using a PSFCH resource indicator field and a SL HARQ timing indicator field. For example, the SL HARQ timing indicator field may indicate the time offset between each initial transmission / retransmission and its associated HARQ feedback resource. For example, the Tx UE 202 may first determine the resources used for the initial transmission and retransmission. Then, the Tx UE 202 may apply the indicated time offset to them and determine the associated HARQ feedback resource on the side link. After the Tx UE 202 decodes the PSFCH resource indicator field and the SL HARQ timing indicator field in the scheduling DCI, it may forward the information to the Rx UE 203, for example, by sending the same field with the same value to the Rx UE 203 in the SCI. Similar to the Tx UE 202, the retransmission based on the scheduling is a blind retransmission or a retransmission based on HARQ feedback, and the Rx UE 203 may determine the scheduled HARQ feedback resource on the side link accordingly. When two-level SCI is applied, the PSFCH resource indicator field and the SL HARQ timing indicator field may be carried by the first-level SCI.

[0291] DCI scheduled retransmission based on HARQ feedback, early termination sent on Uu interface

[0292] DCI scheduled retransmission based on HARQ feedback, early termination sent on Uu interface: In another case, the scheduled DCI may schedule retransmission based on HARQ feedback, early termination sent on Uu interface. An example is shown in Fig. 22In the embodiment of the present invention, SCI is scheduled in time slot 0; the initial transmission, the associated HARQ feedback resources on the side link (from Rx UE 203 to Tx UE 202) or the associated HARQ feedback resources on the Uu interface (from Tx UE 202 to gNB 201) are scheduled in time slot 0, time slot 0 and time slot 1 respectively; the first retransmission, the associated HARQ feedback resources on the side link and the associated HARQ feedback resources on the Uu interface are scheduled in time slot 1, time slot 1 and time slot 2 respectively; the second retransmission, the associated HARQ feedback resources on the side link and the associated HARQ feedback resources on the Uu interface are scheduled in time slot 2, time slot 2 and time slot 3 respectively.

[0293] In the example shown in the figure, the HARQ feedback resources on the Uu interface for initial transmission and the HARQ feedback resources on the side link for the first retransmission are scheduled in the same time slot. In another example, they may be scheduled in different time slots. For example, the initial transmission, the associated HARQ feedback resources on the side link, and the associated HARQ feedback resources on the Uu interface are scheduled in time slot 0, time slot 0, and time slot 1, respectively; the first retransmission, the associated HARQ feedback resources on the side link, and the associated HARQ feedback resources on the Uu interface are scheduled in time slot 2, time slot 2, and time slot 3, respectively; the second retransmission, the associated HARQ feedback resources on the side link, and the associated HARQ feedback resources on the Uu interface are scheduled in time slot 4, time slot 4, and time slot 5, respectively. The side link transmission or the associated HARQ feedback on the side link may be scheduled in the same time slot; or may also be scheduled in different time slots.

[0294] Rx UE 203 can determine the scheduled initial transmission and retransmission by decoding the SCI. For each transmission, Rx UE 203 can send HARQ feedback (e.g., ACK / NACK-based feedback or NACK-only-based feedback) to Tx UE 202 using the scheduled HARQ feedback resources on the sidelink. Tx UE 202 can be scheduled using dedicated HARQ feedback resources on the Uu interface for each initial transmission or retransmission.

[0295] If the scheduled transmission is not successful after the transmission, which may be an initial transmission or a retransmission (excluding the last retransmission), the Tx UE 202 may not send any feedback on the HARQ feedback resources on the Uu interface and may skip it.

[0296] If the scheduled transmission succeeds before the last retransmission, Tx UE 202 may send an early termination indication to gNB 201 to release the reserved resources so that gNB 201 can use them for other purposes. Fig.21 As an example, if the transmission is successful after the first retransmission, the Tx UE 202 may not send the remaining scheduled retransmissions (e.g., the second retransmission in the figure); and send an ACK to the gNB 201 using the associated HARQ feedback resources on the Uu interface (e.g., the HARQ feedback resources on the Uu interface in slot 2 in the figure) to indicate that the remaining reserved resources are released. The Rx UE 203 may skip decoding the remaining scheduled retransmissions and not send feedback on the associated resources on the side link.

[0297] Once the resources reserved by gNB 201 are released, in one scenario, only gNB 201 may schedule other side link transmissions on the released resources. Alternatively, in another scenario, both gNB 201 and Mode 2V2X UE may schedule side link transmissions on the released resources. In one case, one of the above two scenarios may be supported. In another case, both of the above scenarios may be supported. In this case, Tx UE 202 may be notified by gNB 201 whether the released resources can be reused only by gNB 201 or can be reused by both gNB 201 and Mode 2V2X UE. The notification may be performed via DCI signaling (e.g., by scheduling a resource reuse indicator field in the DCI). For example, when the field is set to "0", it indicates that the released resources can only be reused by gNB 201; when the field is set to "1", it indicates that the released resources can be reused by gNB 201 and Mode 2V2X UE. The notification may also be performed via RRC configuration (e.g., via RRC parameter Released-Resource-Reuse). For example, if the UE is configured with Released-Resource-Reuse set to 'gNB only', the released resources can only be reused by gNB 201; if the UE is configured with Released-Resource-Reuse set to 'gNB and mode-2V2XUE', the released resources can be reused by both gNB 201 and mode 2V2X UE.

[0298] If the scheduled transmission is not successful before the last retransmission, Tx UE 202 may send HARQ feedback to gNB 201 based on the HARQ feedback result sent by Rx UE 203 for the last retransmission.

[0299] The scheduling DCI may indicate multiple HARQ feedback resources on the Uu interface using one PUCCH resource indicator field and one UL HARQ timing indicator field. For example, the UL HARQ timing indicator field may indicate the time offset between each initial transmission or retransmission and its associated HARQ feedback resource. For example, the Tx UE 202 may first determine the resources used for the initial transmission or retransmission. Then, the Tx UE 202 may apply the indicated time offset to them and determine the associated HARQ feedback resource on the Uu interface. After the Tx UE 202 decodes the PUCCH resource indicator field or the UL HARQ timing indicator field in the scheduling DCI, it may forward the information to the Rx UE 203, for example, by sending the same field with the same value to the Rx UE 203 in the SCI. Similar to the Tx UE 202, the retransmission based on scheduling is a blind retransmission or a retransmission based on HARQ feedback, and the Rx UE 203 may determine the scheduled HARQ feedback resource on the side link accordingly. When two-level SCI is applied, the PUCCH resource indicator field or the UL HARQ timing indicator field may be carried by the first-level SCI.

[0300] As proposed herein, in some scenarios, both blind retransmissions and retransmissions based on HARQ feedback may be supported. In one approach, a field in the scheduling DCI may be used to indicate which retransmission mode it is scheduling. For example, a retransmission mode indicator field (1 bit) may be carried by the scheduling DCI. When the retransmission mode indicator is set to "0", the retransmissions scheduled by the scheduling DCI along with the initial transmission are blind retransmissions; when the retransmission mode indicator is set to "1", the retransmissions scheduled by the scheduling DCI along with the initial transmission are retransmissions based on HARQ feedback.

[0301] In another scheme, the information of the retransmission mode can be statically configured through RRC. For example, the RRC parameter SL-Retransmission-Mode can be configured, where the value can be 'Blind' and 'HARQ based'. When the UE is configured with SL-Retransmission-Mode set to 'Blind', the retransmission scheduled by the scheduling DCI together with the initial transmission is a blind retransmission; when the UE is configured with SL-Retransmission-Mode set to 'HARQ based', the retransmission scheduled by the scheduling DCI together with the initial transmission is a retransmission based on HARQ feedback.

[0302] After the Tx UE 202 understands the retransmission mode, the Tx UE 202 may forward the information to the Rx UE 203 using the SCI (e.g., through the retransmission mode indicator field (1 bit) in the SCI sent to the Rx UE 203). For example, if the Tx UE 202 is using blind retransmission scheduling, the Tx UE 202 may set the retransmission mode indicator in the SCI to "0"; if the Tx UE 202 is using HARQ feedback-based retransmission scheduling, the Tx UE 202 may set the retransmission mode indicator in the SCI to "1". For the Rx UE 203, it can determine the retransmission mode by decoding the retransmission mode indicator field in the scheduling SCI accordingly.

[0303] For V2X UEs operating in Mode 2, the V2X UE may monitor SCI from other V2X UEs before scheduling sidelink transmissions. Once the V2X UE detects an SCI scheduling a sidelink transmission for another UE and decodes the SCI, for example, by decoding the Resource Reuse Indicator field (1 bit) in the SCI, it may determine whether resource allocations for data transmission and HARQ feedback on the sidelink can be released and reused. When two-level SCI is applied, the Resource Reuse Indicator field may be carried by the first-level SCI.

[0304] For example, if the detected resource reuse indicator field is set to '0', the V2X UE may determine that the resource allocation in the SCI is pre-reserved and will not be released. The V2X UE may ignore the resources reserved in the SCI and search for other available resources.

[0305] If the detected resource reuse indicator field is set to "1", the V2X UE may determine that the resource allocation in the SCI may be released. The V2X UE may monitor the release signaling and reuse the reserved resources if the release signaling is detected. For example, the V2X UE may monitor the HARQ feedback on the resources scheduled by the SCI. If the V2X UE detects that the scheduled transmission is successful before all scheduled transmissions are performed, for example by detecting an ACK feedback in one of the scheduled HARQ feedback resources or by detecting that signaling is not sent in one of the scheduled HARQ feedback resources, the V2X UE may regard the remaining resources originally reserved by the SCI for PSSCH transmission and HARQ feedback as available resources, where the V2X UE may schedule sidelink transmissions on them.

[0306] For Tx UE 202, if the resources in SCI can be released and reused by Mode 2 V2X UE, Tx UE 202 can set the resource reuse indicator field in SCI to "1"; if the resources in SCI will not be released or if the resources in SCI can be released but cannot be reused by Mode 2 V2X UE, Tx UE 202 can set the resource reuse indicator field in SCI to "0".

[0307] In one case, the retransmission mode indicator field and the resource reuse indicator field may be two different fields sent in the SCI. In some other cases, the value of the retransmission mode indicator field and the value of the resource reuse indicator field may have a one-to-one mapping, for example, both fields may be "0" or "1" at the same time. In these cases, only one of the retransmission mode indicator field and the reuse indicator field may be carried by the SCI.

[0308] For example, only the retransmission mode indicator field may be carried by the SCI. A Mode 2 V2X UE may then read the retransmission mode indicator field and determine the information in the same manner as reading the resource reuse indicator field disclosed herein, and vice versa.

[0309] In the SCI, a field may be used to indicate whether the transmission scheduled by the SCI is scheduled by the gNB 201 or the Tx UE 202. For example, the resource allocation mode indicator field (1 bit) may be carried by the scheduling SCI. When the retransmission mode indicator is set to "0", it indicates that the sidelink transmission is scheduled by the gNB 201, for example, mode 1 resource allocation; when the retransmission mode indicator is set to "1", it indicates that the sidelink transmission is scheduled by the V2X UE, for example, mode 2 resource allocation. When two-level SCI is applied, the resource allocation mode indicator field may be carried by the first-level SCI.

[0310] For example, when the mode 2V2X UE detects that the side link transmission is scheduled by the gNB 201, the mode 2V2X UE may consider that the reserved resources cannot be reused and may ignore the resource reuse indicator field in the SCI. The mode 2V2X UE may not monitor the signal sent on the feedback resources scheduled by the SCI. When the mode 2V2X UE detects that the side link transmission is scheduled by another mode 2V2X UE, the mode 2V2X UE may read the resource reuse indicator field in the SCI and determine whether the reserved resources can be reused. If the reserved resources can be reused, the mode 2V2X UE may monitor the signal sent on the feedback resources scheduled by the SCI. In addition, in this example, the resource reuse indicator field may not be sent in the scheduling SCI. For example, the mode 2V2X UE may decode the retransmission mode indicator field in the SCI to determine whether the reserved resources can be reused when the side link transmission is scheduled by another mode 2V2X UE. When the retransmission mode indicator field is set to "0", the reserved resources cannot be reused; when the retransmission mode indicator field is set to "1", the reserved resources can be reused. In this example, the resource allocation mode indicator field and the retransmission mode indicator field can be two different fields in the SCI; or the resource allocation mode indicator and the retransmission mode indicator can be two different bits in one SCI field, for example, the resource allocation mode indicator can be the most significant bit and the retransmission mode indicator can be the least significant bit.

[0311] The subject matter disclosed above may be applied to a case where the gNB 201 schedules CSI feedback on the side link, such as CSI reporting, mobility measurement, beam management measurement, etc. For example, the gNB 201 may send the scheduling of measurement and reporting to both the Tx UE 202 and the Rx UE 203; or the gNB 201 may send the scheduling of measurement and reporting only to the Tx UE 202, and then the Tx UE 202 indicates it to the Rx UE 203 through the SCI. In addition, the Rx UE 203 may send the report to the gNB 201 through the Uu interface; or the Rx UE 203 may send the report to the Tx UE 202 on the side link; or the Rx UE 203 may first send the report to the Tx UE 202, and then the Tx UE 202 may forward the report to the gNB 201 through the Uu interface.

[0312] The above disclosed subject matter is applicable to the shared carrier scenario of the Uu interface and the sidelink shared carrier. An example is shown in Fig.16In this example, the scheduling is independent, which can reduce latency, but requires the UE to have sufficient capabilities for it. Scheduling can also be cross-slot. For example, the scheduled DCI may occur in time slot 0, and the scheduled sidelink transmission may occur in time slot k, where k = 1, 2, 3, etc.

[0313] Some special considerations for multicast use cases: In a multicast scenario, the gNB 201 may send scheduling DCI to multiple Rx UEs 203. Dedicated resources may be used for scheduling DCI for different Rx UEs 203. Alternatively, to reduce overhead, shared resources may be used for scheduling DCI for different Rx UEs 203, see the example below. When shared resources are used, a common search space with the same CORESET may be configured for all UEs in the group.

[0314] Shared resources can be used for scheduling DCI of different Rx UEs Example 1: Scheduling DCI can be SDM. gNB 201 can form multiple beams using the same time and frequency resources to send scheduling DCI to different Rx UEs 203. When multiple Rx UEs 203 are QCLed to the same beam, the scheduling DCI among the Rx UEs 203 QCLed to the same beam can be TDM or FDM, while the scheduling DCI for Rx UEs 203 on different beams can be SDM.

[0315] Shared resources may be used for scheduling DCI of different Rx UEs Example 2: The gNB 201 may send the same scheduling DCI to multiple Rx UEs 203 (e.g., all UEs in a neighboring group) when using an omni-directional antenna, or send the same scheduling DCI to Rx UEs 203 in a neighboring group that are QCLed to the same beam when, for example, scheduling DCI for different beams is SDM, TDM, or FDM. The scheduling DCI may carry both a group / beam common DCI field (in other words, a group common DCI field or a beam common DCI) and a UE-specific DCI field. The group / beam common DCI field carries DCI shared by Rx UEs 203 in a neighboring group or by Rx UEs 203 in a neighboring group that are QCLed to the same beam. For example, the group / beam common DCI field may carry time and frequency resource assignments for transmission / retransmission, a BWP indicator field, a resource indicator field, a transmission / reception indicator field, a slot format indicator field, etc. The UE-specific DCI field carries DCI dedicated to each Rx UE 203, for example, a dedicated DCI field for Rx UE 203 1, a dedicated DCI field for Rx UE 203 2, ..., a dedicated DCI field for Rx UE 203n. For example, the UE-specific DCI field may carry time and frequency resource allocation for HARQ feedback, CSI feedback, etc. Each UE may be configured with a temporary ID within a neighboring group or a temporary ID within a beam. The UE may realize the complete DCI notified by the gNB 201 by checking the group / beam common DCI field and the UE-specific DCI field associated with the configured temporary ID. For example, for a UE configured with UE 1 as a temporary ID, the UE may read the common DCI field or the dedicated DCI field for Rx UE 203 (with ID UE 1) to realize its complete DCI information.

[0316] Shared resources may be used for scheduling DCI example 3 for different Rx UEs: Although the gNB 201 may send the same scheduling DCI to all Rx UEs 203, the scheduling DCI may not carry UE-specific DCI fields. The scheduling DCI may carry only group / beam common DCI fields, and each UE may derive the assigned UE-specific resources from the notified scheduling DCI. For example, according to one option, the DCI may carry an assignment of time and frequency resources for HARQ feedback or CSI feedback for all UEs. The UE may autonomously divide the assigned resources into n parts and send HARQ feedback, CSI report, mobility measurement, beam management measurement, etc. using the part associated with it (e.g., associated with the configured temporary ID). According to another option, the DCI may carry the time and frequency resource assignment for HARQ feedback or CSI feedback for one UE (e.g., a UE configured with Rx UE 203 (with ID UE 1) as a temporary ID). UEs configured with other temporary IDs may autonomously derive the resources it will use from the resource allocation for Rx UE 203 (with ID UE 1). For example, the scheduling DCI may indicate that RB 0 to RB k-1 are allocated to Rx UE 203 (with ID UE 1). Rx UE 203 (another Rx UE 203 with ID UE 2) may autonomously determine that it should use RB k to RB 2k-1 in the same symbol as the allocated resources, etc.

[0317] In the multicast scenario, when Tx UE 202 is scheduled by gNB 201 to send feedback over the Uu interface, Tx UE 202 may send compact feedback information derived from the received feedback from Rx UE 203 to reduce overhead. For HARQ feedback, Tx UE 202 may send one HARQ feedback to gNB 201 to indicate whether retransmission of the entire multicast transmission is required; or Tx UE 202 may send HARQ feedback for each beam to gNB 201 to indicate which beams need to be retransmitted, where a bitmap may be used, for example, {b k-1 ,…,b1,b0} is mapped, b k-1 b0 is mapped to the first beam and b1 is mapped to the kth beam; or Tx UE 202 may indicate to gNB 201 the number of beams for which retransmission needs to be performed. For measurement and reporting, Tx UE 202 may send a recommended MCS level derived from a CSI report from Rx UE 203 to assist gNB 201 in determining the MCS level to be used for sidelink transmission.

[0318] In a multicast scenario, different Rx UEs 203 may have different QoS requirements. Based on the QoS requirements, the Rx UE 203 may be indicated whether the UE will send HARQ feedback to the gNB 201 / Tx UE 202. The Rx UE 203 may be statically configured through RRC configuration or semi-permanently activated and disabled by an activation DCI or dynamically notified of such information by a scheduling DCI. For example, the UE may be configured with an RRC parameter SL-HARQ by the gNB 201, where "on" indicates that HARQ feedback is enabled and "OFF" indicates that HARQ feedback is disabled. Or a one-bit HARQ feedback enable field may be carried by an activation DCI, a disabling DCI, or a scheduling DCI sent by the gNB 201, where "1" indicates that HARQ feedback is enabled and "0" indicates that HARQ feedback is disabled. Similar ideas may be applied to CSI feedback, such as CSI reporting, beam management measurement reporting, mobility RSRP, or RSRQ measurement reporting. For example, through gNB201, the UE can be statically configured through RRC configuration or semi-permanently activated and disabled by activation DCI or dynamically informed by scheduling DCI whether the UE needs to report channel state information.

[0319] In a multicast scenario, for a UE capable of sending HARQ feedback, the UE may feedback ACK when the UE successfully decodes the data, and may feedback NACK when the UE cannot decode the data. Alternatively, according to another option, the UE may feedback NACK only when the UE cannot decode the data. When the UE successfully decodes the data, the UE should not send HARQ feedback on the assigned HARQ feedback resources. In this case, if no feedback is received on the assigned HARQ feedback resources, the TxUE 202 or gNB 201 may consider that the data is successfully received by the Rx UE 203.

[0320] In a multicast scenario, retransmission may be triggered based on the QoS requirement of the transmitter or the QoS requirement of the data, for example, high reliability data may request the Tx UE 202 to receive ACK from all Rx UEs 203 or not receive NACK from any Rx UE 203. Therefore, retransmission may be triggered if the Tx UE 202 does not receive all ACK feedbacks or receives NACK from any Rx UE 203; low reliability data may request the Tx UE 202 to receive NACK from a certain percentage of Rx UEs 203 less than all Rx UEs 203. Through the gNB 201, the Tx UE 202 may be statically configured through RRC configuration or semi-permanently activated and disabled by the activation DCI or dynamically notified of such information by the scheduling DCI. For example, the Tx UE 202 may be configured with an RRC parameter Reliability-Type for indicating the QoS requirement of the data through the gNB 201, and may be configured with an RRC parameter Reliability-Percentage for indicating a threshold for triggering retransmission. Alternatively, according to another example, Tx UE 202 may be configured with an RRC parameter Reliability-Percentage for indicating a threshold for triggering retransmission by gNB 201. A DCI field may be notified by gNB 201 in activation / deactivation DCI or scheduling DCI to indicate the reliability requirement for each scheduled granted data, for example, a one-bit field may be used, "1" indicates high reliability data and "0" indicates high reliability data.

[0321] In a groupcast scenario, once retransmission is triggered, the Tx UE 202 may multicast the retransmission to all Rx UEs 203 in the neighboring group as in the initial transmission. Or the Tx UE 202 may send the retransmission only to the NACKed Rx UE 203 or the NACKed beam. Through the gNB 201, the Tx UE 202 may be statically configured through RRC configuration or semi-permanently activated and disabled by the activation DCI or dynamically notified of such information by the scheduling DCI. For example, the Tx UE 202 may be configured with the RRC parameter SL-Retransmission-Type through the gNB 201. Or a DCI field may be notified by the gNB 201 in the activation / deactivation DCI or the scheduling DCI to indicate how to perform retransmission for each scheduling permission, for example, a one-bit field may be used, "1" indicates multicast retransmission to all Rx UEs 203 and "0" indicates retransmission to the NACKed UE / beam. For the Rx UE 203, when receiving the retransmission, the Rx UE 203 that ACKed the initial transmission may ignore the retransmission; the Rx UE 203 that NACKed the initial transmission may decode the data by decoding the retransmission or catch up to combine the retransmission and the initial transmission.

[0322] Measurement and reporting on side link: Disclosed herein is support for CSI feedback on the side link. The Rx UE 203 may report channel state information, beam management measurement results, or mobility measurement results to the gNB 201 or to the Tx UE 202. Periodic, semi-persistent, and aperiodic measurements or reports may be supported in NR V2X.

[0323] For periodic measurement or reporting, both Tx UE 202 and Rx UE 203 may be configured with an RRC configuration SL-CSI-ReportConfig. The UE may be configured with multiple configurations of SL-CSI-ReportConfig, where each configuration is associated with an ID (e.g., config-ID). Each configuration may carry various information, such as parameters that need to be reported, information about reference signals used to perform measurements, and resources used for reporting.

[0324] The UE can be configured to report a parameter or a set of parameters through RRC configuration SL-CSI-ReportConfig, where the parameter can be type I channel state information, such as CQI, RI, PMI; type II channel state information, such as interference conditions, eigenvalues ​​and eigenvectors of the channel matrix, etc.; RSRP, RSRQ measurements for beam management; RSRP, RSRQ measurements for mobility. The UE can be configured with SSB index, DMRS port, CSI-RS configuration or SRS configuration through RRC configuration SL-CSI-ReportConfig to indicate the reference signal used to perform the measurement. The UE can be configured with time and frequency resources (e.g., time slot index, start and length of symbol, time offset value, start RB index, bitmap of RBs used, number of consecutive RBs used) through RRC configuration SL-CSI-ReportConfig to indicate the resources used for reporting.

[0325] For semi-persistent measurement and reporting, both Tx UE 202 and Rx UE 203 may be configured with multiple RRC configurations SL-CSI-ReportConfig. gNB 201 may use the CSI acquisition and reporting field in the activation DCI to trigger semi-persistent measurement and reporting, for example, 0 indicates that measurement and reporting are not triggered; other values ​​indicate the index of the triggered SL-CSI-ReportConfig. gNB 201 may trigger semi-persistent measurement and reporting by sending an activation DCI to both Tx UE 202 and Rx UE 203. Alternatively, gNB 201 may trigger semi-persistent measurement and reporting by sending an activation DCI to Tx UE 202, and Tx UE 202 indicates the triggered semi-persistent measurement to Rx UR through SCI.

[0326] For non-periodic measurement and reporting, both Tx UE 202 and Rx UE 203 may be configured with multiple RRC configurations SL-CSI-ReportConfig. gNB 201 may schedule non-periodic measurement and reporting using the CSI acquisition and reporting field in the scheduling DCI, for example, 0 indicates that measurement and reporting are not scheduled and other values ​​indicate the index of the scheduled SL-CSI-ReportConfig. gNB 201 may schedule non-periodic measurement and reporting by sending a scheduling DCI to Tx UE 202 or Rx UE 203. Alternatively, gNB 201 may schedule non-periodic measurement and reporting by sending a scheduling DCI to Tx UE 202, and Tx UE 202 indicates the scheduled non-periodic measurement and reporting to Rx UR through SCI.

[0327] RRC-configured resource allocation on the sidelink

[0328] Broadcast sidelink transmission

[0329] Broadcast sidelink transmission: In NR V2X, the gNB 201 or a gNB-like node may statically configure resources used by the UE for broadcast sidelink transmissions. The UE may be statically configured with resources for broadcast sidelink transmissions through RRC configuration. When the UE has data to send on the sidelink, the UE may broadcast control and data using the configured resources without dynamic grant.

[0330] The UE may be statically configured with a broadcast opportunity via RRC. A broadcast opportunity (BO) may be defined as a sidelink resource allocation in time, frequency, and space (e.g., directional antenna or panel or directional beam) for broadcast. The RRC configuration may be configured via a broadcast signal (e.g., OSI) or via a public or dedicated RRC configuration over the Uu interface.

[0331] To support static configuration of the timing for broadcast, groupcast or unicast sidelink transmission in NR V2X, different IEs (e.g., SL-ConfigureGrantConfig-Broadcast, SL-ConfigureGrantConfig-Groupcast, and SL-ConfigureGrantConfig-Unicast) may be used; or the same IE (e.g., SL-ConfigureGrantConfig) may be used, where the type of sidelink transmission (e.g., broadcast, groupcast or unicast) is specified in the IE. IE SL-ConfigureGrantConfig or SL-ConfigureGrantConfig-Broadcast may carry the following RRC configurations: 1) type of sidelink transmission; 2) type of carrier; 3) parameter set of resources; 4) broadcast transmission UE sidelink ID on the sidelink; 5) periodicity of BO; 6) frequency domain resource allocation; or 7) beam scanning information, etc.

[0332] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE SL-ConfigureGrantConfig is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0333] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource assignment is for a shared licensed carrier between Uu and sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource assignment is for a dedicated sidelink carrier.

[0334] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0335] RRC configuration for indicating a broadcast transmit UE sidelink ID on the sidelink. For a broadcast sidelink transmit, the UE may be configured with the UE ID on the sidelink as a source ID or a destination ID. For example, the UE may be configured with a sidelink broadcast transmit RNTI (SL-BT-RNTI) for use as a source ID. The UE may be configured with a sidelink broadcast receive RNTI (SL-BR-RNTI) for use as a destination ID, where each destination ID may be associated with a different service.

[0336] When generating SCI for broadcast sidelink transmission, the scrambling sequence for SCI can be initialized jointly by the source ID and the destination ID. Or the scrambling sequence for SCI can be initialized by one of the source ID or the destination ID, the other of which is indicated in the SCI payload. For example, the destination ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0337] RRC configuration used to indicate the periodicity of BO.

[0338] RRC configuration for indicating time domain resource allocation. We disclose that the time domain resources for BO can be configured using the following alternatives:

[0339] Alternative 1: The UE may be configured with one or more bitmaps to indicate the time domain resources used for BO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0340] Alternative 2: The UE may be configured with a time offset, a starting point, and a duration to indicate the time domain resources used for the BO. The UE may be configured with a slot / subframe offset for the BO relative to SFN=0. The UE may be configured with a starting index to indicate the starting point of the BO, where the starting index may be a symbol index or a mini-slot index within a time slot. The UE may be configured with the number of symbols or the number of mini-slots to indicate the duration of the BO. The above parameters may be configured with separate configurations, or some parameters may be configured collectively. For example, a predefined table may include combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be configured with an index of the table to indicate the value of the start or duration.

[0341] For broadcast sidelink transmissions, the UE may transmit the same information in multiple directions. The UE may be configured with one time domain resource, and the time domain resources used for all directions may be determined by some predefined rules. Or the UE may be configured with a time domain resource for each direction separately. For example, the UE may be indicated with multiple start and duration values ​​for the time domain resource. Or the UE may be indicated with a gap between the time domain resources used for transmission in a first direction and transmission in the remaining directions.

[0342] For broadcast sidelink transmissions, the configured grants may configure time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be configured jointly, for example, one time domain resource allocation may be used for both PSCCH or PSSCH. Alternatively, the time domain resources for PSCCH or PSSCH may be configured separately, with the configured grants configuring two time domain resources for PSCCH or PSSCH, respectively.

[0343] RRC configuration for indicating frequency domain resource allocation. The UE may be configured with continuous frequency resources for BO. The frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). According to an alternative, the UE may be configured with parameters StartRB and LengthRB, or the UE may be configured with parameters StartRBG and LengthRBG. According to another alternative, the frequency resources may be configured by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be configured with an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0344] For broadcast sidelink transmissions, the configured grants may configure frequency domain resources for both PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be configured jointly, for example, if PSCCH and PSSCH are TDMed and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two frequency domain resources for PSCCH and PSSCH, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0345] RRC configuration for indicating beam scanning information. For broadcast sidelink transmissions, the transmitter UE 202 may broadcast information to multiple directions using multiple beams.

[0346] Alternative 1: The gNB 201 may determine the number of beam scans that the UE needs to perform and may configure the determined value for the UE in a configured grant. The UE may provide assistance information to the NB to assist the NB in ​​determining the beam scan configuration. Such assistance information may include one or more of the following: V2X services of interest, UE capabilities, such as in terms of the number of simultaneous beam scan directions that the UE can cover, UE scheduling preferences (including power saving mode preferences), etc.

[0347] Assuming that the UE is configured to broadcast information through k directions / beams, the UE may be configured with k BOs for each beam respectively. Or the UE may be configured with one BO for all beams. The beams used for beam scanning may be configured by the gNB 201. Or the beams used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0348] Alternative 2: The number of beam scans may be determined by the UE. The UE may be configured with one BO including multiple symbols or mini-slots through RRC. The UE may autonomously use the configured symbols and mini-slots within the BO for beam scans. The beam used for beam scans may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0349] The UE may be dynamically indicated with an SFI. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0350] If there is a conflict between the BO configured by RRC and the SFI notified by DCI, the DCI may rewrite the RRC configuration. The UE may skip the conflicting symbols and not perform sidelink transmission on them. If the BO is configured in a mini-slot and there is a conflict for a portion of the symbols in the mini-slot, the UE may skip the entire mini-slot and not perform sidelink transmission on it. Or the UE may only skip the conflicting symbols and perform sidelink transmission on non-conflicting symbols within the mini-slot.

[0351] Unicast sidelink transmission

[0352] In NR V2X, the gNB 201 or a gNB-like node may statically configure resources used by the UE for unicast sidelink transmission. We disclose that the UE may be statically configured with resources for unicast sidelink transmission / reception through RRC configuration. When the UE has data to send on the sidelink, the UE may unicast control and data to the paired UE using the configured resources without dynamic grant.

[0353] We disclose that a UE may be statically configured with unicast opportunities via RRC. A unicast opportunity (UO) may be defined as an allocation of sidelink resources in time, frequency, and space (e.g., directional antennas or panels or directional beams) for unicast. The RRC configuration may be configured via a broadcast signal (e.g., OSI) or via a public or dedicated RRC configuration over the Uu interface. We disclose that an IE SL-ConfigureGrantConfig or SL-ConfigureGrantConfig-Unicast may carry the following RRC configurations: 1) type of sidelink transmission; 2) type of carrier; 3) parameter set of resources; 4) unicast UE ID on the sidelink; 5) unicast pairing UE ID; 6) periodicity of UO; 7) time domain resources; 8) number of repetitions and redundancy versions; 9) frequency domain resources; 10) HARQ feedback information; or 11) retransmission related information, etc.

[0354] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE SL-ConfigureGrantConfig is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0355] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource assignment is for a shared licensed carrier between Uu and sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource assignment is for a dedicated sidelink carrier.

[0356] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0357] RRC configuration for indicating unicast UE ID on sidelink. For unicast sidelink communication, the UE may be configured with a UE ID, such as SL-U-RNTI. For transmitter UE 202, the UE may use SL-U-RNTI as source ID. For receiver UE 203, the UE may use SL-U-RNTI as destination ID.

[0358] RRC configuration for indicating unicast paired UE ID. In order to perform unicast sidelink communication, the UE needs to know the information of the paired UE. The UE can be configured with the paired UE's ID through RRC in the configured grant, for example, SL-UP-RNTI. For the transmitter UE 202, the paired UE's ID can be used as the destination ID. For the receiver UE 203, the paired UE's ID can be used as the source ID.

[0359] When generating an SCI for unicast sidelink transmission, the scrambling sequence for the SCI may be initialized jointly by the source ID and the destination ID. Or the scrambling sequence for the SCI may be initialized by one of the source ID and the destination ID, the other of which is indicated in the SCI payload. For example, the destination ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0360] RRC configuration used to indicate the periodicity of UO.

[0361] RRC configuration for indicating time domain resource allocation. We disclose that the time domain resources for UO can be configured using the following alternatives:

[0362] Alternative 1: The UE may be configured with one or more bitmaps to indicate the time domain resources used for UO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0363] Alternative 2: The UE may be configured with a time offset, a starting point, and a duration to indicate the time domain resources used for the UO. The UE may be configured with a slot / subframe offset of the UO relative to SFN=0. The UE may be configured with a starting index to indicate the starting point of the UO, where the starting index may be a symbol index or a mini-slot index within a slot. The UE may be configured with the number of symbols or the number of mini-slots to indicate the duration of the UO. The above parameters may be configured with separate configurations, or some parameters may be configured together. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be configured with an index to the table to indicate the values ​​of the start and duration.

[0364] For unicast sidelink transmissions, the configured grants may configure time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be configured jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH or PSSCH may be configured separately, with the configured grants configuring two time domain resources for PSCCH or PSSCH, respectively.

[0365] RRC configuration to indicate the number of repetitions and the redundancy version (RV). To improve reliability, the UE may repeat unicast sidelink transmissions. The UE may be configured with the number of repetitions and the RV through RRC configuration via gNB 201. Similar ideas may be applied to multicast sidelink transmissions. When the UE repeats the initial transmission, either inter-slot repetition or intra-slot repetition may be performed. The UE may use the same symbol or mini-slot in a subsequent slot for repetition. Alternatively, the UE may use symbols or mini-slots in the same slot for repetition.

[0366] RRC configuration for indicating HARQ feedback related information. The UE may be configured with a number for the HARQ process. The UE may be configured with one UO for both transmission and feedback. The resources used for feedback (e.g., the time offset between transmission and feedback) may be indicated in the SCI in the transmission. Or the UE may be configured with dedicated UOs for transmission and feedback, respectively. The UO for transmission and the UO for feedback may be configured with a one-to-one mapping. When receiving a transmission, the receiver UE 203 may send feedback using the associated feedback UO.

[0367] RRC configuration for indicating retransmission related information. When NACK is received by the transmitter UE 202, it can perform retransmission. The UE can be configured with a dedicated UO for retransmission. The UO for transmission and the UO for feedback can be configured with a one-to-one mapping. When a NACK is received, the transmitter UE 202 can use the associated retransmission UO to send the retransmission. Or a dedicated retransmission UO may not be configured. The UE can use the resources in the configured UO for transmission and retransmission. The resources used for retransmission (for example, the time offset between transmission and retransmission) can be indicated in the SCI in the transmission or in the feedback sent by the receiver UE203.

[0368] RRC configuration for indicating frequency domain resource allocation. The UE may be configured with continuous frequency resources for UO. The frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). According to an alternative, the UE may be configured with parameters StartRB and LengthRB, or the UE may be configured with parameters StartRBG and LengthRBG. According to another alternative, the frequency resources may be configured by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be configured with an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0369] For unicast sidelink transmissions, the configured grants may configure frequency domain resources for PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be configured jointly, for example, if PSCCH or PSSCH is TDM and uses the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two frequency domain resources for PSCCH and PSSCH, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0370] The UE may be dynamically indicated with an SFI. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0371] If there is a conflict between the UO configured by RRC and the SFI notified by DCI, the DCI may rewrite the RRC configuration. The UE may skip the conflicting symbols and not perform sidelink transmission on them. If the UO is configured in a mini-slot and there is a conflict for a portion of the symbols in the mini-slot, the UE may skip the entire mini-slot and not perform sidelink transmission on it. Or the UE may only skip the conflicting symbols and perform sidelink transmission on non-conflicting symbols within the mini-slot.

[0372] Multicast sidelink transmission

[0373] Multicast sidelink transmission: In NR V2X, the gNB 201 or a gNB-like node may statically configure resources used by the UE for multicast sidelink transmission. We disclose that the UE may be statically configured with resources for multicast sidelink transmission / repetition through RRC configuration. When the UE has data to send on the sidelink, the UE may multicast control and data to a group of UEs using the configured resources without dynamic grant.

[0374] We disclose that a UE may be statically configured with a multicast opportunity via RRC. A groupcast opportunity (GO) may be defined as an allocation of sidelink resources in time, frequency, and space (e.g., directional antennas or panels or directional beams) for multicast. The RRC configuration may be configured via a broadcasted signal (e.g., OSI) or via a public or dedicated RRC configuration over the Uu interface. We disclose that an IE SL-ConfigureGrantConfig or SL-ConfigureGrantConfig-Groupcast may carry the following RRC configuration:

[0375] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE SL-ConfigureGrantConfig is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0376] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource assignment is for a shared licensed carrier between Uu and sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource assignment is for a dedicated sidelink carrier.

[0377] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0378] RRC configuration used to indicate the group transmission ID on the sidelink. For multicast sidelink transmission, the UE may be configured with a UE ID on the sidelink. For example, the UE may be configured with a UE ID, such as SL-G-RNTI. If the UE needs to multicast on the sidelink, the UE may use the SL-G-RNTI as the source ID in the formed group.

[0379] RRC configuration used to indicate the group ID on the sidelink. The UE may be configured with a group ID, such as SL-GD-RNTI. The UE may use the configured group ID as the destination group ID.

[0380] When generating SCI, the scrambling sequence for SCI can be initialized jointly by the destination group ID and the source ID. Or the scrambling sequence for SCI can be initialized by one of the destination group ID and the source ID, and the other of the destination group ID and the source ID is indicated in the SCI payload. For example, the destination group ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0381] RRC configuration used to indicate the periodicity of GO.

[0382] RRC configuration for indicating time domain resource allocation. We disclose that time domain resources for GO can be configured using the following alternatives:

[0383] Alternative 1: The UE may be configured with one or more bitmaps to indicate the time domain resources used for GO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a fis mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0384] Alternative 2: The UE may be configured with a time offset, a starting point, and a duration to indicate the time domain resources used for the GO. The UE may be configured with a time slot / subframe offset of the GO relative to SFN=0. The UE may be configured with a starting index to indicate the starting point of the GO, where the starting index may be a symbol index or a mini-slot index within a time slot. The UE may be configured with the number of symbols or the number of mini-slots to indicate the duration of the GO. The above parameters may be configured with separate configurations, or some parameters may be configured collectively. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be configured with an index of the table to indicate the values ​​of the start and duration.

[0385] For multicast sidelink transmission, the UE may transmit the same information in multiple directions. The UE may be configured with one time domain resource, and the time domain resource for all directions may be determined by some predefined rules. Or the UE may be configured with a time domain resource for each direction separately. For example, the UE may be indicated with multiple start and duration values ​​for the time domain resource. Or the UE may be indicated with a gap between the time domain resources for transmission in the first direction and the time domain resources for transmission in the remaining directions.

[0386] For multicast sidelink transmissions, the configured grants may configure time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be configured jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two time domain resources for PSCCH and PSSCH, respectively.

[0387] RRC configuration for indicating the number of repetitions and redundancy version (RV). To improve reliability, the UE may repeat the multicast sidelink transmission. Through the gNB 201, the UE may be configured with the number of repetitions and the RV through RRC configuration. When the UE repeats the initial transmission, inter-slot repetition or intra-slot repetition may be performed. The UE may use the same symbol or mini-slot in a subsequent slot for repetition. Or the UE may use symbols or mini-slots in the same slot for repetition. If beam scanning is applied in multicast, the transmitter UE 202 may repeat the entire beam scanning, for example, beam 1, beam 2, ..., beam k, beam 1, beam 2, ..., beam k, ..., beam 1, beam 2, ..., beam k. Or the UE may repeat for each beam and then perform beam scanning, for example, beam 1, beam 1, ..., beam 1, beam 2, beam 2, ..., beam 2, ..., beam k, beam k, ..., beam k.

[0388] RRC configuration for indicating HARQ feedback related information. The UE may be configured with a HARQ process number. The UE may be configured with a GO for both transmission and feedback. The resources used for feedback (e.g., the time offset between transmission and feedback) may be indicated in the SCI in the transmission. Or the UE may be configured with dedicated GOs for transmission and feedback, respectively. The GO for transmission and the GO for feedback may be configured with a one-to-one mapping. When receiving the transmission, the receiver UE 203 may send feedback using the associated feedback GO.

[0389] RRC configuration for indicating retransmission related information. When NACK is received by the transmitter UE 202, it can perform retransmission. The UE can be configured with a dedicated GO for retransmission. The GO for transmission and the GO for feedback can be configured with a one-to-one mapping. When a NACK is received, the transmitter UE 202 can use the associated retransmission GO to send the retransmission. Or a dedicated retransmission GO may not be configured. The UE can use the resources in the configured GO for transmission and retransmission. The resources for retransmission (e.g., the time offset between transmission and retransmission) can be indicated in the SCI in the transmission or in the feedback sent by the receiver UE203.

[0390] RRC configuration for indicating frequency domain resource allocation. The UE may be configured with contiguous frequency resources for GO. The frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). According to an alternative, the UE may be configured with parameters StartRB and LengthRB, or the UE may be configured with parameters StartRBG and LengthRBG. According to another alternative, the frequency resources may be configured by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be configured with an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0391] For multicast sidelink transmissions, the configured grants may configure frequency domain resources for PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be configured jointly, for example, if PSCCH and PSSCH are TDMed and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two frequency domain resources for PSCCH or PSSCH, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0392] RRC configuration for indicating beam scanning information. For multicast sidelink transmission, the transmitter UE 202 may use multiple beams to multicast information to multiple directions.

[0393] Alternative 1: The gNB 201 may determine the number of beam scannings that the UE needs to perform and may configure the determined value for the UE in a configured grant. Assuming that the UE is configured to multicast information over k directions / beams, the UE may be configured with k GOs for each beam, respectively. Or the UE may be configured with one GO for all beams. The beams used for beam scanning may be configured by the gNB 201. Or the beams used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0394] Alternative 2: The number of beam scans may be determined by the UE. The UE may be configured with one GO including multiple symbols or mini-slots through RRC. The UE may autonomously use the configured symbols and mini-slots within the GO for beam scans. The beam used for beam scans may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0395] The UE may be dynamically indicated with an SFI. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0396] If there is a conflict between the GO configured by RRC and the SFI notified by DCI, the DCI may rewrite the RRC configuration. The UE may skip the conflicting symbols and not perform sidelink transmission on them. If the GO is configured in a mini-slot and there is a conflict for a portion of the symbols in the mini-slot, the UE may skip the entire mini-slot and not perform sidelink transmission on it. Or the UE may only skip the conflicting symbols and perform sidelink transmission on non-conflicting symbols within the mini-slot.

[0397] Activation / deactivation based resource allocation on sidelink

[0398] Broadcast sidelink transmission

[0399] Broadcast sidelink transmission: In NR V2X, the gNB 201 or a gNB-like node may semi-permanently allocate resources for broadcast sidelink transmission by the UE. We disclose that the UE may be semi-permanently informed of the resources for broadcast sidelink transmission through RRC configuration and activation DCI. When the UE has data to send on the sidelink, the UE may broadcast control and data using the activated resources without dynamic grant. The gNB 201 may disable the activated resources using a disable DCI.

[0400] We disclose that a UE may be semi-permanently assigned a broadcast opportunity via RRC and activation DCI. A broadcast opportunity (BO) may be defined as a sidelink resource allocation in time, frequency, and space (e.g., directional antenna or panel or directional beam) for broadcast. The RRC configuration may be configured via a broadcast signal (e.g., OSI) or via a public or dedicated RRC configuration over the Uu interface.

[0401] Detailed design for RRC configuration: To semi-persistently allocate opportunities for broadcast, groupcast or unicast sidelink transmission in NR V2X, we disclose that different IEs (e.g., SL-ConfigureGrantConfig-Broadcast, SL-ConfigureGrantConfig-Groupcast, and SL-ConfigureGrantConfig-Unicast) may be used; or the same IE (e.g., SL-ConfigureGrantConfig) may be used, where the type of sidelink transmission (e.g., broadcast, groupcast or unicast) is specified in the IE. We disclose that the IE SL-ConfigureGrantConfig or SL-ConfigureGrantConfig-Broadcast may carry the following RRC configuration to convey information of the BO to be activated:

[0402] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE SL-ConfigureGrantConfig is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0403] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource assignment is for a shared licensed carrier between Uu and sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource assignment is for a dedicated sidelink carrier.

[0404] RRC configuration for indicating the index of candidate resources. The UE may be configured with multiple BOs to be activated. Each BO may be associated with a dedicated resource index. For example, RRC configuration NR-BO-Index. The UE may determine which BO is activated / deactivated by activating / deactivating DCI.

[0405] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0406] RRC configuration for indicating a broadcast transmit UE sidelink ID on the sidelink. For a broadcast sidelink transmit, the UE may be configured with the UE ID on the sidelink as a source ID or a destination ID. For example, the UE may be configured with a sidelink broadcast transmit RNTI (SL-BT-RNTI) for use as a source ID. The UE may be configured with a sidelink broadcast receive RNTI (SL-BR-RNTI) for use as a destination ID, where each destination ID may be associated with a different service.

[0407] When generating SCI for broadcast sidelink transmission, the scrambling sequence for SCI may be initialized jointly by the source ID and the destination ID. Or the scrambling sequence for SCI may be initialized by one of the source ID and the destination ID, the other of which is indicated in the SCI payload. For example, the destination ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0408] RRC configuration used to indicate the periodicity of BO.

[0409] RRC configuration for indicating time domain resource allocation. We disclose that the time domain resources for BO can be configured using the following alternatives:

[0410] Alternative 1: The UE may be configured with one or more bitmaps to indicate the time domain resources used for BO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0411] Alternative 2: The UE may be configured with a time offset, a starting point, and a duration to indicate the time domain resources used for the BO. The UE may be configured with a slot / subframe offset for the BO relative to SFN=0. The UE may be configured with a starting index to indicate the starting point of the BO, where the starting index may be a symbol index or a mini-slot index within a time slot. The UE may be configured with the number of symbols or the number of mini-slots to indicate the duration of the BO. The above parameters may be configured with separate configurations, or some parameters may be configured collectively. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be configured with an index to the table to indicate the values ​​of the start and duration.

[0412] For broadcast sidelink transmissions, the UE may transmit the same information in multiple directions. The UE may be configured with one time domain resource, and the time domain resources used for all directions may be determined by some predefined rules. Or the UE may be configured with a time domain resource for each direction separately. For example, the UE may be indicated with multiple start and duration values ​​for the time domain resource. Or the UE may be indicated with a gap between the time domain resources used for transmission in a first direction and transmission in the remaining directions.

[0413] For broadcast sidelink transmissions, the configured grant may configure time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be configured jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH and PSSCH may be configured separately, with the configured grant configuring two time domain resources for PSCCH and PSSCH, respectively.

[0414] RRC configuration for indicating frequency domain resource allocation. The UE may be configured with continuous frequency resources for BO. The frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). According to an alternative, the UE may be configured with parameters StartRB and LengthRB, or the UE may be configured with parameters StartRBG and LengthRBG. According to another alternative, the frequency resources may be configured by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be configured with an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0415] For broadcast sidelink transmissions, the configured grants may configure frequency domain resources for PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be configured jointly, for example, if PSCCH and PSSCH are TDMed and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two frequency domain resources for PSCCH and PSSCH, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0416] RRC configuration for indicating beam scanning information. For broadcast sidelink transmissions, the transmitter UE 202 may broadcast information to multiple directions using multiple beams.

[0417] Alternative 1: gNB 201 may determine the number of beam scanning that the UE needs to perform, and may configure the determined value for the UE in a configured grant. Assuming that the UE is configured to broadcast information through k directions / beams, the UE may be configured with k BOs for each beam, respectively. Or the UE may be configured with one BO for all beams. The beams used for beam scanning may be configured by gNB 201. Or the beams used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0418] Alternative 2: The number of beam scans may be determined by the UE. The UE may be configured with one BO including multiple symbols or mini-slots through RRC. The UE may autonomously use the configured symbols and mini-slots within the BO for beam scans. The beam used for beam scans may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0419] Detailed design for activating / deactivating DCI: Activating / deactivating DCI can be used to semi-permanently activate / deactivate BO. In order to distinguish the activating / deactivating DCI from other DCI, a new RNTI (e.g., SL-CS-RNTI) can be used to scramble the CRC of the activating / deactivating DCI. In order to distinguish the activating / deactivating DCI for BO, GO, and UO, the activating / deactivating DCI payload can carry a field for indicating the type of side link communication activated / deactivated. Or different RNTIs (e.g., SL-BO-CS-RNTI, SL-GO-CS-RNTI, SL-UO-CS-RNTI) can be used to scramble the CRC of the activating / deactivating DCI for BO, GO, and UO, respectively. The UE can be configured with the RNTI for activating DCI through RRC.

[0420] The activation / deactivation DCI may also carry information of the BO to be activated / deactivated. We disclose that the activation / deactivation DCI for BO may carry the following information:

[0421] Activation / Deactivation Flag Field. One bit may be used in an activation / deactivation DCI to indicate whether the DCI is used for activation or for deactivation, for example, "0" indicates that the DCI is used for activation and "1" indicates that the DCI is used for deactivation.

[0422] Resource indicator field. The UE may be configured with multiple BOs to be activated / deactivated via RRC. The activation / deactivation DCI may indicate the index of the BO to be activated / deactivated for broadcast sidelink transmission. Assuming the UE is configured with 8 BOs, e.g., BO 0 to BO 7, a 3-bit resource indicator field may be used, with "000" indicating BO 0, "001" indicating BO 1, and so on.

[0423] Sidelink Type Indicator Field. The activating DCI may indicate the type of sidelink transmission. For example, a 2-bit Sidelink Type Indicator field may be used, with "00" indicating that the DCI is activating a broadcast sidelink transmission, "01" indicating that the DCI is activating a multicast sidelink transmission, "10" indicating that the DCI is activating a unicast sidelink transmission, etc., and "11" indicating that the DCI is activating resources for all types of sidelink transmissions.

[0424] Carrier type indicator field. Using one bit in the scheduling DCI, the UE can be semi-permanently indicated the type of carrier. For example, if the carrier type indicator field is set to "0", the UE determines that the sidelink resource allocation is for the shared licensed carrier between Uu and the sidelink; if the carrier type indicator field is set to "1", the UE determines that the sidelink resource allocation is for the dedicated sidelink carrier.

[0425] Time Domain Resource Allocation Field. The Time Domain Resource Allocation field can carry the time domain resource allocation for BO using the following alternatives:

[0426] Alternative 1: The UE may be notified of one or more bitmaps to indicate the time domain resources used for BO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. Two bit strings can be signaled by activating DCI, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0427] Alternative 2: The UE may be notified of the time offset, starting point and duration to indicate the time domain resources used for the BO. The UE may be notified of the time slot / subframe offset of the BO. The time offset may be relative to the time slot / subframe carrying the activation DCI. The UE may be notified of the starting index to indicate the starting point of the BO, where the starting index may be a symbol index or a mini-slot index within the time slot. The UE may be notified of the number of symbols or the number of mini-slots to indicate the duration of the BO. The above parameters may be notified using separate fields, or some parameters may be notified jointly. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be notified of the index of the table to indicate the values ​​of the start and duration.

[0428] For broadcast sidelink transmission, the UE may send the same information in multiple directions. The UE may be notified of one time domain resource, and the time domain resources for all directions are determined by some predefined rules. Or the UE may be notified of the time domain resources for each direction separately. For example, the UE may be indicated with multiple start and duration values ​​of the time domain resources. Or the UE may be indicated with the gap between the time domain resources for transmission in the first direction and the transmission in the remaining directions.

[0429] For broadcast sidelink transmission, the activation DCI may notify the time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be notified jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH and PSSCH may be notified separately, and the activation DCI may notify two time domain resources for PSCCH and PSSCH, respectively.

[0430] Frequency domain resource allocation field. The frequency domain resource allocation field may carry frequency domain resource allocation for BO. The UE may be notified of contiguous frequency resources for BO. The frequency resources may be notified per RB, or may be notified per subchannel (e.g., per RBG). According to one alternative, the UE may be notified of the index of the lowest RB and the number of allocated RBs, or the UE may be notified of the index of the lowest RBG and the number of allocated RBGs. According to another alternative, the frequency resource allocation may be notified by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be notified of an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0431] For broadcast sidelink transmission, the activation DCI may notify the frequency domain resources for PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be notified jointly, for example, if PSCCH and PSSCH are TDM and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be notified separately, and the activation DCI may notify two frequency domain resources for PSCCH and PSSCH, respectively.

[0432] Beam scanning information field. For multicast sidelink transmission, the transmitter UE 202 may use the following alternatives to multicast information in multiple directions using multiple beams:

[0433] Alternative 1: gNB 201 may determine the number of beam scannings that the UE needs to perform and notify the UE by activating DCI. Assuming that the UE is notified by multicasting information through k directions / beams, the UE may be notified of one BO for all beams. The beams used for beam scanning may be configured by gNB 201. Or the beams used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0434] Alternative 2: The number of beam scans may be determined by the UE. The UE may be notified of a BO containing multiple symbols or mini-slots by an activation DCI. The UE may autonomously use the notified symbols and mini-slots within the BO for beam scanning. The beam used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0435] If some information of BO is indicated by activation DCI (for example, time domain resource allocation, frequency domain resource allocation, etc.), gNB201 does not configure the same information in the RRC configuration.

[0436] The UE may be dynamically indicated with an SFI. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0437] If there is a conflict between the semi-persistently allocated BO and the SFI notified by the DCI, the DCI may rewrite the allocation. The UE may skip the conflicting symbols and not perform sidelink transmission on them. If the BO is allocated per mini-slot and there is a conflict for a portion of the symbols in the mini-slot, the UE may skip the entire mini-slot and not perform sidelink transmission on it. Or the UE may only skip the conflicting symbols and perform sidelink transmission on non-conflicting symbols within the mini-slot.

[0438] Unicast sidelink transmission

[0439] Unicast sidelink transmission: In NR V2X, the gNB 201 or a gNB-like node may semi-permanently allocate resources for unicast sidelink transmission by the UE. We disclose that the UE may be semi-permanently informed of the resources for unicast sidelink transmission / reception through RRC configuration and activation DCI. When the UE has data to transmit on the sidelink, the UE may use the activated resources to unicast control and data without dynamic grant. The gNB 201 may disable the activated resources using a disable DCI.

[0440] We disclose that a UE may be semi-permanently assigned a unicast opportunity through RRC and activation DCI. A unicast opportunity (UO) may be defined as a sidelink resource allocation in time, frequency, and space (e.g., directional antenna or panel or directional beam) for unicast. The RRC configuration may be configured through a broadcast signal (e.g., OSI) or through a public or dedicated RRC configuration over the Uu interface.

[0441] Detailed design for RRC configuration: We disclose that IE SL-ConfigureGrantConfig or SL-ConfigureGrantConfig-Unicast can carry the following RRC configuration to convey the information of the UO to be activated:

[0442] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE SL-ConfigureGrantConfig is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0443] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource assignment is for a shared licensed carrier between Uu and sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource assignment is for a dedicated sidelink carrier.

[0444] RRC configuration for indicating the index of candidate resources. The UE may be configured with multiple UOs to be activated. Each UO may be associated with a dedicated resource index. For example, RRC configuration NR-UO-Index. The UE may determine which UO is activated / deactivated by activating / deactivating DCI.

[0445] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0446] RRC configuration for indicating unicast UE ID on sidelink. For unicast sidelink communication, the UE may be configured with a UE ID, such as SL-U-RNTI. For transmitter UE 202, the UE may use SL-U-RNTI as source ID. For receiver UE 203, the UE may use SL-U-RNTI as destination ID.

[0447] RRC configuration for indicating unicast paired UE ID. In order to perform unicast sidelink communication, the UE needs to know the information of the paired UE. The UE can be configured with the paired UE's ID through RRC in the configured grant, for example, SL-UP-RNTI. For the transmitter UE 202, the paired UE's ID can be used as the destination ID. For the receiver UE 203, the paired UE's ID can be used as the source ID.

[0448] When generating an SCI for unicast sidelink transmission, the scrambling sequence for the SCI may be initialized jointly by the source ID and the destination ID. Or the scrambling sequence for the SCI may be initialized by one of the source ID and the destination ID, the other of which is indicated in the SCI payload. For example, the destination ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0449] RRC configuration used to indicate the periodicity of UO.

[0450] RRC configuration for indicating time domain resource allocation. We disclose that the time domain resources for UO can be configured using the following alternatives:

[0451] Alternative 1: The UE may be configured with one or more bitmaps to indicate the time domain resources used for UO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0452] Alternative 2: The UE may be configured with a time offset, a starting point, and a duration to indicate the time domain resources used for the UO. The UE may be configured with a slot / subframe offset of the UO relative to SFN=0. The UE may be configured with a starting index to indicate the starting point of the UO, where the starting index may be a symbol index or a mini-slot index within a slot. The UE may be configured with the number of symbols or the number of mini-slots to indicate the duration of the UO. The above parameters may be configured with separate configurations, or some parameters may be configured together. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be configured with an index to the table to indicate the values ​​of the start and duration.

[0453] For unicast sidelink transmissions, the configured grants may configure time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be configured jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two time domain resources for PSCCH and PSSCH, respectively.

[0454] RRC configuration to indicate the number of repetitions and the redundancy version (RV). To improve reliability, the UE may repeat unicast sidelink transmissions. The UE may be configured with the number of repetitions and the RV through RRC configuration via gNB 201. Similar ideas may be applied to multicast sidelink transmissions. When the UE repeats the initial transmission, either inter-slot repetition or intra-slot repetition may be performed. The UE may use the same symbol or mini-slot in a subsequent slot for repetition. Alternatively, the UE may use symbols or mini-slots in the same slot for repetition.

[0455] RRC configuration for indicating HARQ feedback related information. The UE may be configured with a number for the HARQ process. The UE may be configured with one UO for both transmission and feedback. The resources used for feedback (e.g., the time offset between transmission and feedback) may be indicated in the SCI in the transmission. Or the UE may be configured with dedicated UOs for transmission and feedback, respectively. The UO for transmission and the UO for feedback may be configured with a one-to-one mapping. When receiving a transmission, the receiver UE 203 may send feedback using the associated feedback UO.

[0456] RRC configuration for indicating retransmission related information. When NACK is received by the transmitter UE 202, it can perform retransmission. The UE can be configured with a dedicated UO for retransmission. The UO for transmission and the UO for feedback can be configured with a one-to-one mapping. When a NACK is received, the transmitter UE 202 can use the associated retransmission UO to send the retransmission. Or a dedicated retransmission UO may not be configured. The UE can use the resources in the configured UO for transmission and retransmission. The resources used for retransmission (for example, the time offset between transmission and retransmission) can be indicated in the SCI in the transmission or in the feedback sent by the receiver UE203.

[0457] RRC configuration for indicating frequency domain resource allocation. The UE may be configured with continuous frequency resources for UO. The frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). According to an alternative, the UE may be configured with parameters StartRB and LengthRB, or the UE may be configured with parameters StartRBG and LengthRBG. According to another alternative, the frequency resources may be configured by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be configured with an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0458] For unicast sidelink transmissions, the configured grants may configure frequency domain resources for PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be configured jointly, for example, if PSCCH and PSSCH are TDMed and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two frequency domain resources for PSCCH and PSSCH, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0459] Detailed design for activating / disabling DCI: Activating / disabling DCI can be used to semi-permanently activate / disable UO. In order to distinguish the activating / disabling DCI from other DCI, a new RNTI (e.g., SL-CS-RNTI) can be used to scramble the CRC of the activating / disabling DCI. In order to distinguish the activating / disabling DCI for BO, GO, and UO, the activating / disabling DCI payload can carry a field for indicating the type of side link communication activated / disabled. Or different RNTIs (e.g., SL-BO-CS-RNTI, SL-GO-CS-RNTI, SL-UO-CS-RNTI) can be used to scramble the CRC of the activating / disabling DCI for BO, GO, and UO, respectively. The UE can be configured with the RNTI for activating DCI through RRC.

[0460] The activation / deactivation DCI may also carry information of the UO to be activated / deactivated. We disclose that the activation / deactivation DCI for a UO may carry the following information:

[0461] Activation / Deactivation Flag Field. One bit may be used in an activation / deactivation DCI to indicate whether the DCI is used for activation or for deactivation, for example, "0" indicates that the DCI is used for activation and "1" indicates that the DCI is used for deactivation.

[0462] Resource indicator field. The UE may be configured with multiple UOs to be activated / deactivated via RRC. The activation / deactivation DCI may indicate the index of the UO to be activated / deactivated for unicast sidelink transmission. Assuming the UE is configured with 8 UOs, e.g., UO 0 to UO 7, a 3-bit resource indicator field may be used, with "000" indicating UO 0, "001" indicating UO 1, and so on.

[0463] Sidelink Type Indicator Field. The activating DCI may indicate the type of sidelink transmission. For example, a 2-bit Sidelink Type Indicator field may be used, with "00" indicating that the DCI is activating a broadcast sidelink transmission, "01" indicating that the DCI is activating a multicast sidelink transmission, "10" indicating that the DCI is activating a unicast sidelink transmission, etc., and "11" indicating that the DCI is activating resources for all types of sidelink transmissions.

[0464] Carrier type indicator field. Using one bit in the scheduling DCI, the UE can be semi-permanently indicated the type of carrier. For example, if the carrier type indicator field is set to "0", the UE determines that the sidelink resource allocation is for the shared licensed carrier between Uu and the sidelink; if the carrier type indicator field is set to "1", the UE determines that the sidelink resource allocation is for the dedicated sidelink carrier.

[0465] Unicast Sidelink UE ID field. For unicast sidelink communications, the UE may be semi-permanently informed of the sidelink UE ID, e.g., SL-U-RNTI. For the transmitter UE 202, the UE may use the SL-U-RNTI as the source ID. For the receiver UE 203, the UE may use the SL-U-RNTI as the destination ID. The activation DCI may explicitly indicate the UE ID, e.g., SL-U-RNTI. Alternatively, the UE may be configured with 2 n UE IDs, where each UE ID is associated with an index. The activation DCI may use an n-bit field to indicate the index for the UE to determine the UE ID.

[0466] Unicast Pairing UE ID field. The UE may be semi-permanently informed of the paired UE ID. When the UE needs to send on the unicast sidelink, the Pairing UE ID field indicates the ID of the receiver UE 203. When the UE is in receive mode, the Pairing UE ID field indicates the ID of the transmitter UE 202. The activation DCI may explicitly indicate the pairing UE ID, for example, SL-UP-RNTI. Alternatively, the UE may be configured with 2 pairs of UE IDs via RRC. n Pairing UE IDs, where each pairing UE ID is associated with an index. The activation DCI may use an n-bit field to indicate the index for the UE to determine the pairing UE ID.

[0467] Time Domain Resource Allocation Field. The Time Domain Resource Allocation field can carry the time domain resource allocation for the UO using the following alternatives:

[0468] Alternative 1: The UE may be notified of one or more bitmaps to indicate the time domain resources used for the UO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. Two bit strings can be signaled by activating DCI, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0469] Alternative 2: The UE may be notified of the time offset, starting point and duration to indicate the time domain resources used for the UO. The UE may be notified of the slot / subframe offset of the UO. The time offset may be relative to the slot / subframe carrying the activation DCI. The UE may be notified of the starting index to indicate the starting point of the UO, where the starting index may be a symbol index or a mini-slot index within the slot. The UE may be notified of the number of symbols or the number of mini-slots to indicate the duration of the UO. The above parameters may be notified using separate fields, or some parameters may be notified jointly. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be notified of the index of the table to indicate the values ​​of the start and duration.

[0470] For unicast sidelink transmission, the activation DCI may notify the time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be notified jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH and PSSCH may be notified separately, and the activation DCI may notify two time domain resources for PSCCH and PSSCH, respectively.

[0471] Repeat indicator field. To improve reliability, the UE may repeat unicast sidelink transmissions. The UE may be notified of the number of repetitions by the activation DCI. The UE may also be notified of the RV mode. For example, the RRC configuration may configure the UE with multiple candidate modes of RV, each mode being associated with an index. The UE may be notified of the index to indicate which mode is used for repetition. When the UE repeats the initial transmission, inter-slot repetition or intra-slot repetition may be performed. The UE may use the same symbol or mini-slot in a subsequent slot for repetition. Alternatively, the UE may use symbols or mini-slots in the same slot for repetition.

[0472] HARQ process field: The UE may be notified of the HARQ process number by the activation DCI.

[0473] Frequency domain resource allocation field. The frequency domain resource allocation field may carry frequency domain resource allocation for UO. The UE may be notified of continuous frequency resources for UO. The frequency resources may be notified per RB, or may be notified per subchannel (e.g., per RBG). According to one alternative, the UE may be notified of the index of the lowest RB and the number of allocated RBs, or the UE may be notified of the index of the lowest RBG and the number of allocated RBGs. According to another alternative, the frequency resource allocation may be notified by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be notified of an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0474] For unicast sidelink transmission, the activation DCI may notify the frequency domain resources for PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be notified jointly, for example, if PSCCH and PSSCH are TDM and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be notified separately, and the activation DCI may notify two frequency domain resources for PSCCH and PSSCH, respectively.

[0475] If some information of UO is indicated by activation DCI (e.g., time domain resource allocation, frequency domain resource allocation, etc.), gNB201 does not configure the same information in the RRC configuration.

[0476] The UE may be dynamically indicated with an SFI. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0477] If there is a conflict between the semi-persistently allocated UO and the SFI notified by the DCI, the DCI may rewrite the allocation. The UE may skip the conflicting symbols and not perform sidelink transmission on them. If the UO is allocated according to the mini-slot and there is a conflict for a part of the symbols in the mini-slot, the UE may skip the entire mini-slot and not perform sidelink transmission on it. Or the UE may only skip the conflicting symbols and perform sidelink transmission on non-conflicting symbols within the mini-slot.

[0478] Multicast sidelink transmission

[0479] Multicast sidelink transmission: In NR V2X, the gNB 201 or a gNB-like node may semi-permanently allocate resources for multicast sidelink transmission by the UE. We disclose that the UE may be semi-permanently informed of the resources for multicast sidelink transmission / reception through RRC configuration and activation DCI. When the UE has data to send on the sidelink, the UE may use the activated resources for multicast control and data without dynamic grant. The gNB 201 may disable the activated resources using a disable DCI.

[0480] We disclose that a UE may be semi-permanently assigned a multicast opportunity through RRC and activation DCI. A groupcast opportunity (GO) may be defined as a sidelink resource allocation in time, frequency, and space (e.g., directional antenna or panel or directional beam) for multicast. The RRC configuration may be configured through a broadcast signal (e.g., OSI) or through a public or dedicated RRC configuration over the Uu interface.

[0481] Detailed design for RRC configuration: We disclose that IE SL-ConfigureGrantConfig or SL-ConfigureGrantConfig-Groupcast can carry the following RRC configuration to convey the information of the GO to be activated:

[0482] RRC configuration used to indicate the type of sidelink transmission. For example, RRC configuration NR-SL-CommuncationType, if the same IE SL-ConfigureGrantConfig is used for all sidelink transmission types, then NR-SL-CommuncationType can be Broadcast, Groupcast or Unicast.

[0483] RRC configuration used to indicate the type of carrier. For example, the RRC configuration NR-SL-CarrierType may be used. If NR-SL-CarrierType is configured as "Shared", the UE determines that the sidelink resource assignment is for a shared licensed carrier between Uu and sidelink. If NR-SL-CarrierType is configured as "Dedicated", the UE determines that the sidelink resource assignment is for a dedicated sidelink carrier.

[0484] RRC configuration for indicating the index of candidate resources. The UE may be configured with multiple GOs to be activated. Each GO may be associated with a dedicated resource index. For example, RRC configuration NR-GO-Index. The UE may determine which GO is activated / deactivated by activating / deactivating DCI.

[0485] RRC configuration for indicating the parameter set of resources used for sidelink transmission. For example, RRC configuration NR-SL-Numerology, which can be 15, 30, 60KHz, etc.

[0486] RRC configuration for indicating a multicast transmission ID on the sidelink. For multicast sidelink transmissions, the UE may be configured with a UE ID on the sidelink. For example, the UE may be configured with a UE ID, such as the SL-G-RNTI. If the UE needs to multicast on the sidelink, the UE may use the SL-G-RNTI as the source ID in the formed group.

[0487] RRC configuration used to indicate the group ID on the sidelink. The UE may be configured with a group ID, such as SL-GD-RNTI. The UE may use the configured group ID as the destination group ID.

[0488] When generating SCI, the scrambling sequence for SCI can be initialized jointly by the destination group ID and the source ID. Or the scrambling sequence for SCI can be initialized by one of the destination group ID and the source ID, and the other of the destination group ID and the source ID is indicated in the SCI payload. For example, the destination group ID is used to scramble the SCI, and the source ID is carried by the SCI payload.

[0489] RRC configuration used to indicate the periodicity of GO.

[0490] RRC configuration for indicating time domain resource allocation. We disclose that time domain resources for GO can be configured using the following alternatives:

[0491] Alternative 1: The UE may be configured with one or more bitmaps to indicate the time domain resources used for GO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. The two bit strings can be configured via RRC configuration, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0492] Alternative 2: The UE may be configured with a time offset, a starting point, and a duration to indicate the time domain resources used for the GO. The UE may be configured with a time slot / subframe offset of the GO relative to SFN=0. The UE may be configured with a starting index to indicate the starting point of the GO, where the starting index may be a symbol index or a mini-slot index within a time slot. The UE may be configured with the number of symbols or the number of mini-slots to indicate the duration of the GO. The above parameters may be configured with separate configurations, or some parameters may be configured collectively. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be configured with an index of the table to indicate the values ​​of the start and duration.

[0493] For multicast sidelink transmission, the UE may transmit the same information in multiple directions. The UE may be configured with one time domain resource, and the time domain resource for all directions may be determined by some predefined rules. Or the UE may be configured with a time domain resource for each direction separately. For example, the UE may be indicated with multiple start and duration values ​​for the time domain resource. Or the UE may be indicated with a gap between the time domain resources for transmission in the first direction and the time domain resources for transmission in the remaining directions.

[0494] For multicast sidelink transmissions, the configured grants may configure time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be configured jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two time domain resources for PSCCH and PSSCH, respectively.

[0495] RRC configuration for indicating the number of repetitions and the redundancy version (RV). To improve reliability, the UE may repeat the multicast sidelink transmission. Through the gNB 201, the UE may be configured with the number of repetitions and the RV through RRC configuration. Similar ideas may be applied to multicast sidelink transmission. When the UE repeats the initial transmission, inter-slot repetition or intra-slot repetition may be performed. The UE may use the same symbol or mini-slot in a subsequent slot for repetition. Or the UE may use symbols or mini-slots in the same slot for repetition. If beam scanning is applied in multicast, the transmitter UE 202 may repeat the entire beam scanning, for example, beam 1, beam 2, ..., beam k, beam 1, beam 2, ..., beam k, ..., beam 1, beam 2, ..., beam k. Or the UE may repeat for each beam and then perform beam scanning, for example, beam 1, beam 1,…, beam 1, beam 2, beam 2,…, beam 2,…, beam k, beam k,…, beam k.

[0496] RRC configuration for indicating HARQ feedback related information. The UE may be configured with a HARQ process number. The UE may be configured with a GO for both transmission and feedback. The resources used for feedback (e.g., the time offset between transmission and feedback) may be indicated in the SCI in the transmission. Or the UE may be configured with dedicated GOs for transmission and feedback, respectively. The GO for transmission and the GO for feedback may be configured with a one-to-one mapping. When receiving the transmission, the receiver UE 203 may send feedback using the associated feedback GO.

[0497] RRC configuration for indicating retransmission related information. When NACK is received by the transmitter UE 202, it can perform retransmission. The UE can be configured with a dedicated GO for retransmission. The GO for transmission and the GO for feedback can be configured with a one-to-one mapping. When a NACK is received, the transmitter UE 202 can use the associated retransmission GO to send the retransmission. Or a dedicated retransmission GO may not be configured. The UE can use the resources in the configured GO for transmission and retransmission. The resources for retransmission (e.g., the time offset between transmission and retransmission) can be indicated in the SCI in the transmission or in the feedback sent by the receiver UE203.

[0498] RRC configuration for indicating frequency domain resource allocation. The UE may be configured with contiguous frequency resources for GO. The frequency resources may be configured in RBs, or may be configured in subchannels (e.g., RBGs). According to an alternative, the UE may be configured with parameters StartRB and LengthRB, or the UE may be configured with parameters StartRBG and LengthRBG. According to another alternative, the frequency resources may be configured by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be configured with an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0499] For multicast sidelink transmissions, the configured grants may configure frequency domain resources for PSCCH or PSSCH. The frequency domain resources for PSCCH and PSSCH may be configured jointly, for example, if PSCCH and PSSCH are TDMed and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be configured separately, with the configured grants configuring two frequency domain resources for PSCCH and PSSCH, respectively, for example, StartRBG-PSCCH, LengthRBG-PSCCH and StartRBG-PSSCH, LengthRBG-PSSCH.

[0500] RRC configuration for indicating beam scanning information. For multicast sidelink transmission, the transmitter UE 202 may use multiple beams to multicast information to multiple directions.

[0501] Alternative 1: The gNB 201 may determine the number of beam scannings that the UE needs to perform and may configure the determined value for the UE in a configured grant. Assuming that the UE is configured to multicast information over k directions / beams, the UE may be configured with k GOs for each beam, respectively. Or the UE may be configured with one GO for all beams. The beams used for beam scanning may be configured by the gNB 201. Or the beams used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0502] Alternative 2: The number of beam scans may be determined by the UE. The UE may be configured with one GO including multiple symbols or mini-slots through RRC. The UE may autonomously use the configured symbols and mini-slots within the GO for beam scans. The beam used for beam scans may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0503] Detailed design for activating / deactivating DCI: Activating / deactivating DCI can be used to semi-permanently activate / deactivate GO. In order to distinguish the activating / deactivating DCI from other DCI, a new RNTI (e.g., SL-CS-RNTI) can be used to scramble the CRC of the activating / deactivating DCI. In order to distinguish the activating / deactivating DCI for BO, GO, and UO, the activating / deactivating DCI payload can carry a field for indicating the type of side link communication activated / deactivated. Or different RNTIs (e.g., SL-BO-CS-RNTI, SL-GO-CS-RNTI, SL-UO-CS-RNTI) can be used to scramble the CRC of the activating / deactivating DCI for BO, GO, and UO, respectively. The UE can be configured with the RNTI for activating DCI through RRC.

[0504] The activation / deactivation DCI may also carry information of the GO to be activated / deactivated. We disclose that the activation / deactivation DCI for the GO may carry the following information:

[0505] Activation / Deactivation Flag Field. One bit may be used in an activation / deactivation DCI to indicate whether the DCI is used for activation or for deactivation, for example, "0" indicates that the DCI is used for activation and "1" indicates that the DCI is used for deactivation.

[0506] Resource Indicator Field. The UE may be configured with multiple GOs to be activated / deactivated via RRC. The activation / deactivation DCI may indicate the index of the GO to be activated / deactivated for multicast sidelink transmission. Assuming the UE is configured with 8 GOs, e.g., GO 0 to GO 7, a 3-bit Resource Indicator field may be used, with "000" indicating GO 0, "001" indicating GO 1, and so on.

[0507] Sidelink Type Indicator Field. The activating DCI may indicate the type of sidelink transmission. For example, a 2-bit Sidelink Type Indicator field may be used, with "00" indicating that the DCI is activating a broadcast sidelink transmission, "01" indicating that the DCI is activating a multicast sidelink transmission, "10" indicating that the DCI is activating a unicast sidelink transmission, etc., and "11" indicating that the DCI is activating resources for all types of sidelink transmissions.

[0508] Carrier type indicator field. Using one bit in the scheduling DCI, the UE can be semi-permanently indicated the type of carrier. For example, if the carrier type indicator field is set to "0", the UE determines that the sidelink resource allocation is for the shared licensed carrier between Uu and the sidelink; if the carrier type indicator field is set to "1", the UE determines that the sidelink resource allocation is for the dedicated sidelink carrier.

[0509] The UE ID field is sent by multicast. The UE can be semi-permanently informed of the UE ID in the group to indicate the source ID. The activation DCI can explicitly indicate the UE ID, for example, SL-G-RNTI. Or the UE can be configured with 2 n The activation DCI may use an n-bit field to indicate the index for the UE to determine the source ID.

[0510] The UE may be semi-permanently informed of the group ID to indicate the destination group ID. The activation DCI may explicitly indicate the group ID, for example, SL-GD-RNTI. Alternatively, the UE may be configured with 2 n The activation DCI may use an n-bit field to indicate the index for the UE to determine the group ID.

[0511] Time Domain Resource Allocation Field. The Time Domain Resource Allocation field can carry the time domain resource allocation for the GO using the following alternatives:

[0512] Alternative 1: The UE may be informed of one or more bitmaps to indicate the time domain resources used for GO. The bitmap may indicate resources in a subframe, slot, mini-slot, or symbol. For example, if a bitmap is used to indicate resources in a symbol, it may be mapped to symbols within a time interval, e.g., {b s ,b s-1 ,…,b1,b0} is mapped, b s is mapped to the first symbol and b0 is mapped to the last symbol. If a bitmap is used to indicate resources in a mini-slot, it can be mapped to the mini-slots within the time interval. For example, {b m ,b m-1 ,…,b1,b0} is mapped, b m is mapped to the first mini-slot and b0 is mapped to the last mini-slot. Alternatively, to save mapping bits, a two-level mapping can be used. Two bit strings can be signaled by activating DCI, for example, {a f ,a f-1 ,…,a1,a0} are mapped to subframes or time slots, a f is mapped to the first subframe or time slot and a0 is mapped to the last subframe or time slot in the time interval. s ,c s-1 ,…,c1,c0} are mapped to symbols within a frame or time slot, or {c m ,c m-1 ,…,c1,c0} are mapped to mini-slots within a frame or time slot.

[0513] Alternative 2: The UE may be notified of the time offset, starting point and duration to indicate the time domain resources used for the GO. The UE may be notified of the time slot / subframe offset of the GO. The time offset may be relative to the time slot / subframe carrying the activation DCI. The UE may be notified of the starting index to indicate the starting point of the GO, where the starting index may be a symbol index or a mini-slot index within the time slot. The UE may be notified of the number of symbols or the number of mini-slots to indicate the duration of the GO. The above parameters may be notified using separate fields, or some parameters may be notified jointly. For example, a predefined table may contain combinations of starts and durations of time domain resources, each combination being associated with an index. The UE may be notified of the index of the table to indicate the values ​​of the start and duration.

[0514] For multicast sidelink transmission, the UE may send the same information in multiple directions. The UE may be notified of one time domain resource, and the time domain resources used for all directions are determined by some predefined rules. Or the UE may be notified of the time domain resources used for each direction separately. For example, the UE may be indicated multiple start and duration values ​​of the time domain resources. Or the UE may be indicated the gap between the time domain resources used for transmission in the first direction and the transmission in the remaining directions.

[0515] For multicast sidelink transmission, the activation DCI may notify the time domain resources for PSCCH or PSSCH. The time domain resources for PSCCH and PSSCH may be notified jointly, for example, one time domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the time domain resources for PSCCH and PSSCH may be notified separately, and the activation DCI may notify two time domain resources for PSCCH and PSSCH, respectively.

[0516] Repeat indicator field. To improve reliability, the UE may repeat the multicast sidelink transmission. The UE may be notified of the number of repetitions by the activation DCI. The UE may also be notified of the RV mode. For example, the RRC configuration may configure the UE with multiple candidate modes of RV, each mode being associated with an index. The UE may be notified of the index to indicate which mode is used for repetition. When the UE repeats the initial transmission, inter-slot repetition or intra-slot repetition may be performed. The UE may use the same symbol or mini-slot in a subsequent slot for repetition. Alternatively, the UE may use symbols or mini-slots in the same slot for repetition.

[0517] HARQ process field: The UE may be notified of the HARQ process number by the activation DCI.

[0518] Frequency domain resource allocation field. The frequency domain resource allocation field may carry the frequency domain resource allocation for the GO. The UE may be notified of the contiguous frequency resources for the GO. The frequency resources may be notified per RB, or may be notified per subchannel (e.g., per RBG). According to one alternative, the UE may be notified of the index of the lowest RB and the number of allocated RBs, or the UE may be notified of the index of the lowest RBG and the number of allocated RBGs. According to another alternative, the frequency resource allocation may be notified by a bitmap. Each bit in the bitmap may indicate an RB, an RBG, or a subchannel. The UE may be notified of an index to indicate the starting RB, RBG, or subchannel associated with the bitmap.

[0519] For multicast sidelink transmission, the activation DCI may notify the frequency domain resources for both PSCCH and PSSCH. The frequency domain resources for PSCCH and PSSCH may be notified jointly, for example, if PSCCH and PSSCH are TDM and use the same number of RBs, one frequency domain resource allocation may be used for both PSCCH and PSSCH. Alternatively, the frequency domain resources for PSCCH and PSSCH may be notified separately, and the activation DCI may notify two frequency domain resources for PSCCH and PSSCH, respectively.

[0520] Beam scanning information field. For multicast sidelink transmission, the transmitter UE 202 may use the following alternatives to multicast information in multiple directions using multiple beams:

[0521] Alternative 1: gNB 201 may determine the number of beam scannings that the UE needs to perform and notify the UE by activating DCI. Assuming that the UE is notified by multicasting information through k directions / beams, the UE may be notified of one BO for all beams. The beams used for beam scanning may be configured by gNB 201. Or the beams used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0522] Alternative 2: The number of beam scans may be determined by the UE. The UE may be notified of a BO containing multiple symbols or mini-slots by an activation DCI. The UE may autonomously use the notified symbols and mini-slots within the BO for beam scanning. The beam used for beam scanning may be autonomously determined by the transmitter UE 202 based on sensing or discovery.

[0523] If some information of GO is indicated by activation DCI (for example, time domain resource allocation, frequency domain resource allocation, etc.), gNB201 does not configure the same information in the RRC configuration.

[0524] The UE may be dynamically indicated with an SFI. For a UE configured with a dedicated sidelink carrier, the UE may perform sidelink transmissions only on symbols marked with "S". Alternatively, the UE may perform sidelink transmissions on symbols marked with "S" or "U". For a UE configured with a shared sidelink carrier between Uu and sidelink, the UE may perform sidelink transmissions only on symbols marked with "S".

[0525] If there is a conflict between the semi-persistently allocated GO and the SFI notified by the DCI, the DCI may rewrite the allocation. The UE may skip the conflicting symbols and not perform sidelink transmission on them. If the GO is allocated per mini-slot and there is a conflict for a portion of the symbols in the mini-slot, the UE may skip the entire mini-slot and not perform sidelink transmission on it. Or the UE may skip only the conflicting symbols and perform sidelink transmission on non-conflicting symbols within the mini-slot.

[0526] It should be understood that performing the steps shown here (such as, Figure 3 , Figure 4 , Figure 6 , Figure 7 and Figure 10-Figure 20 ) may be a logical entity. The steps may be stored in a device, a server, or a computer system (such as, Fig. 9C or Fig.9D The exemplary methods disclosed herein (e.g., Figure 3 , Figure 4 , Figure 6 and Figure 7 ) between omitted steps, combined steps or added steps. Table 5 includes exemplary abbreviations and definitions as disclosed herein.

[0527] Table 5 - Abbreviations and definitions

[0528]

[0529]

[0530] Figure 8901. An exemplary display (e.g., a graphical user interface) that may be generated based on the methods, systems, and apparatus for Uu-based sidelink control for NR V2X as discussed herein is shown. A display interface 901 (e.g., a touch screen display) may provide text in a block 902 associated with Uu-based sidelink control for NR V2X, such as RRC-related parameters, method flow, and current conditions of RRC associations. The progress of any step discussed herein (e.g., a message sent or the success of a step) may be displayed in block 902. In addition, a graphical output 902 may be displayed on the display interface 901. The graphical output may be a topology of an apparatus implementing the methods, systems, and apparatus for Uu-based sidelink control for NR V2X, a graphical output of the progress of any method or system discussed herein, etc.

[0531] The 3rd Generation Partnership Project (3GPP) develops technical standards for cellular telecommunication network technologies, including radio access, core transport networks, and service capabilities - including work on codecs, security, and quality of service. Recent radio access technology (RAT) standards include WCDMA (commonly referred to as 3G), LTE (commonly referred to as 4G), LTE-Advanced standards, and New Radio (NR) (also referred to as "5G"). 3GPP NR standard development is expected to continue and include the definition of next generation radio access technology (new RAT), which is expected to include providing new flexible radio access below 7 GHz and providing new ultra-mobile broadband radio access above 7 GHz. The flexible radio access is expected to include new non-backward compatible radio access in new spectrum below 6 GHz, and it is expected to include different operating modes that can be multiplexed together in the same spectrum to address a wide set of 3GPP NR use cases with different requirements. The ultra-mobile broadband is expected to include cmWave and mmWave spectrum, which will provide opportunities for ultra-mobile broadband access for, for example, indoor applications and hotspots. In particular, ultra-mobile broadband is expected to share a common design framework with sub-7 GHz flexible radio access, leveraging cmWave and mmWave specific design optimizations.

[0532] 3GPP has identified various use cases that NR is expected to support, resulting in various user experience requirements for data rate, latency and mobility. Use cases include the following general categories: enhanced mobile broadband (eMBB) ultra-reliable low latency communication (URLLC), massive machine type communication (mMTC), network operations (e.g., network slicing, routing, migration and interworking, energy saving) and enhanced vehicle-to-everything (eV2X) communication, which may include any of vehicle-to-vehicle communication (V2V), vehicle-to-infrastructure communication (V2I), vehicle-to-network communication (V2N), vehicle-to-pedestrian communication (V2P) and vehicle communication with other entities. Specific services and applications within these categories include, for example, monitoring and sensor networks, device remote control, two-way remote control, personal cloud computing, video streaming, wireless cloud-based office, first responder connectivity, automotive automatic emergency call system (ecall), disaster warning, real-time gaming, multi-person video calling, autonomous driving, augmented reality, tactile Internet, virtual reality, home automation, robotics and aerial drones, etc. All of these use cases and others are contemplated here.

[0533] Fig. 9A 1 shows an exemplary communication system 100 in which the methods and apparatus described and claimed herein for Uu-based sidelink control for NR V2X may be used, such as Figure 3 , Figure 4 , Figure 6 , Figure 7 and Figure 10-Figure 20 The communication system 100 may include a wireless transmit / receive unit (WTRU) 102a, 102b, 102c, 102d, 102e, 102f, or 102g (generally or collectively may be referred to as WTRU 102 or WTRUs 102). The communication system 100 may include a radio access network (RAN) 103 / 104 / 105 / 103b / 104b / 105b, a core network 106 / 107 / 109, a public switched telephone network (PSTN) 108, the Internet 110, other networks 112, and network services 113. The network services 113 may include, for example, a V2X server, a V2X function, a ProSe server, a ProSe function, an IoT service, video streaming, or edge computing.

[0534] It will be appreciated that the concepts disclosed herein may be used with any number of WTRUs, base stations, networks, or network elements. Each of the WTRUs 102a, 102b, 102c, 102d, 102e, 102f, or 102g may be any type of device or apparatus configured to operate or communicate in a wireless environment. Although each WTRU 102a, 102b, 102c, 102d, 102e, 102f, or 102g may be configured to operate or communicate in a wireless environment, the WTRU 102a, 102b, 102c, 102d, 102e, 102f, or 102g may be configured to operate or communicate in a wireless environment. Fig. 9A , Fig. 9B , Fig. 9C , Fig.9D , Fig.9E or Fig.9F Although described as a handheld wireless communication device, it should be understood that for various use cases envisioned for 5G wireless communications, each WTRU may include or be implemented in any type of device or apparatus configured to send or receive wireless signals, including, by way of example only, a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop computer, a tablet computer, a netbook, a notebook computer, a personal computer, a wireless sensor, a consumer electronic device, a wearable device (such as a smart watch or smart clothing), a medical or e-health device, a robot, an industrial equipment, a drone, a vehicle (such as a car, bus, truck, train or airplane), etc.

[0535] The communication system 100 may also include a base station 114a and a base station 114b. Fig. 9AIn the example of FIG. 1 , each base station 114 a and 114 b is depicted as a single element. In practice, the base stations 114 a and 114 b may include any number of interconnected base stations or network elements. The base station 114 a may be any type of device configured to wirelessly connect to at least one of the WTRUs 102 a, 102 b, and 102 c to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, network services 113, or other networks 112. Similarly, the base station 114b may be any type of device configured to connect in a wired or wireless manner with at least one of the remote radio heads (RRHs) 118a, 118b, the transmit and receive points (TRPs) 119a, 119b, or the roadside units (RSUs) 120a and 120b to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, other networks 112, or network services 113. The RRHs 118a, 118b may be any type of device configured to connect in a wireless manner with at least one WTRU 102 (e.g., WTRU 102c) to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, the network services 113, or other networks 112.

[0536] The TRPs 119a, 119b may be any type of device configured to wirelessly connect with at least one WTRU 102d to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, network services 113, or other networks 112. The RSUs 120a and 120b may be any type of device configured to wirelessly connect with at least one of the WTRUs 102e or 102f to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, other networks 112, or network services 113. By way of example, the base stations 114a, 114b may be base transceiver stations (BTS), Node-Bs, eNode Bs, Home Node Bs, Home eNode Bs, next generation Node-Bs (gNode Bs), satellites, site controllers, access points (APs), wireless routers, and the like.

[0537] The base station 114a may be part of the RAN 103 / 104 / 105, which may also include other base stations or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. Similarly, the base station 114b may be part of the RAN 103b / 104b / 105b, which may also include other base stations or network elements (not shown), such as a BSC, a RNC, a relay node, etc. The base station 114a may be configured to send or receive wireless signals within a specific geographic area, which may be referred to as a cell (not shown). Similarly, the base station 114b may be configured to send or receive wired or wireless signals within a specific geographic area, which may be referred to as a cell (not shown) for the methods, systems, and apparatus for Uu-based sidelink control for NR V2X as disclosed herein. Similarly, the base station 114b may be configured to send or receive wired or wireless signals within a specific geographic area, which may be referred to as a cell (not shown). The cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Therefore, in an example, the base station 114a may include three transceivers, for example, one transceiver for each sector of the cell. In an example, the base station 114a may employ multiple-input multiple-output (MIMO) technology, and therefore, multiple transceivers may be used for each sector of the cell.

[0538] The base station 114a may communicate with one or more of the WTRUs 102a, 102b, 102c, or 102g via an air interface 115 / 116 / 117, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115 / 116 / 117 may be established using any suitable radio access technology (RAT).

[0539] The base station 114b may communicate with one or more of the RRHs 118a, 118b, TRPs 119a, 119b, or RSUs 120a, 120b via a wired or air interface 115b / 116b / 117b, which may be any suitable wired (e.g., cable, optical fiber, etc.) or wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115b / 116b / 117b may be established using any suitable radio access technology (RAT).

[0540] The RRH 118a, 118b, TRP 119a, 119b or RSU 120a, 120b may communicate with one or more of the WTRUs 102c, 102d, 102e, 102f via an air interface 115c / 116c / 117c, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115c / 116c / 117c may be established using any suitable radio access technology (RAT).

[0541] The WTRUs 102a, 102b, 102c, 102d, 102e, or 102f may communicate with each other (e.g., sidelink communications) via an air interface 115d / 116d / 117d, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115d / 116d / 117d may be established using any suitable radio access technology (RAT).

[0542] The communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a and the WTRUs 102a, 102b, 102c in the RAN 103 / 104 / 105 or the RRHs 118a, 118b, TRPs 119a, 119b and RSUs 120a, 120b and the WTRUs 102c, 102d, 102e, 102f in the RAN 103b / 104b / 105b may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117 or 115c / 116c / 117c, respectively. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) or High Speed ​​Uplink Packet Access (HSUPA).

[0543] In an example, the base station 114a and the WTRUs 102a, 102b, 102c or the RRHs 118a, 118b, TRPs 119a, 119b or RSUs 120a, 120b and the WTRUs 102c, 102d in the RAN 103b / 104b / 105b may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish an air interface 115 / 116 / 117 or 115c / 116c / 117c, respectively, using Long Term Evolution (LTE) or LTE-Advanced (LTE-A). In the future, the air interface 115 / 116 / 117 or 115c / 116c / 117c may implement 3GPP NR technology. LTE and LTE-A technologies may include LTE D2D and V2X technologies and interfaces (such as sidelink communications, etc.). Similarly, 3GPP NR technology includes NR V2X technology and interfaces (such as sidelink communication, etc.).

[0544] The base station 114a and the WTRUs 102a, 102b, 102c and 102g in the RAN 103 / 104 / 105 or the RRHs 118a, 118b, TRPs 119a, 119b or RSUs 120a, 120b and the WTRUs 102c, 102d, 102e, 102f in the RAN 103b / 104b / 105b may implement a radio technology such as IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSMEDGE (GERAN), etc.

[0545] Fig. 9AThe base station 114c in the example may be, for example, a wireless router, a Home Node B, a Home eNode B, or an access point, and may use any suitable RAT to facilitate wireless connectivity in a local area (such as a business location, a home, a vehicle, a train, an airplane, a satellite, a factory, a campus, etc.) to implement the methods, systems, and apparatus for Uu-based sidelink control for NR V2X as disclosed herein. In an example, the base station 114c and the WTRU 102 (e.g., WTRU 102e) may implement a radio technology (such as IEEE 802.11) to establish a wireless local area network (WLAN). Similarly, the base station 114c and the WTRU 102d may implement a radio technology (such as IEEE 802.15) to establish a wireless personal area network (WPAN). In another example, the base station 114c and the WTRU 102 (e.g., WTRU 102e) may establish a picocell or femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, NR, etc.). Fig. 9A As shown in FIG, base station 114c may have a direct connection to Internet 110. Therefore, base station 114c may not need to access Internet 110 via core network 106 / 107 / 109.

[0546] The RAN 103 / 104 / 105 or RAN 103b / 104b / 105b may be in communication with a core network 106 / 107 / 109, which may be any type of network configured to provide voice, data, messaging, authorization and authentication, application, or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. For example, the core network 106 / 107 / 109 may provide call control, billing services, mobile location-based services, pre-paid telephony, Internet connectivity, packet data network connectivity, Ethernet connectivity, video distribution, etc., or perform high-level security functions (such as user authentication).

[0547] Although not in Fig. 9AAlthough not shown in the figure, it will be appreciated that the RAN 103 / 104 / 105 or RAN 103b / 104b / 105b or the core network 106 / 107 / 109 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 103 / 104 / 105 or RAN 103b / 104b / 105b or a different RAT. For example, in addition to being connected to the RAN 103 / 104 / 105 or RAN 103b / 104b / 105b, which may be employing E-UTRA radio technology, the core network 106 / 107 / 109 may also be in communication with another RAN (not shown) employing GSM or NR radio technology.

[0548] The core network 106 / 107 / 109 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d, 102e to access the PSTN 108, the Internet 110, or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired or wireless communication networks owned or operated by other service providers. For example, the networks 112 may include any type of packet data network (e.g., an IEEE 802.3 Ethernet network) or another core network connected to one or more RANs, which may employ the same RAT as the RAN 103 / 104 / 105 or the RAN 103b / 104b / 105b or a different RAT.

[0549] Some or all of the WTRUs 102a, 102b, 102c, 102d, 102e, and 102f in the communication system 100 may include multi-mode capabilities, for example, the WTRUs 102a, 102b, 102c, 102d, 102e, and 102f may include multiple transceivers for communicating with different wireless networks via different wireless links, in order to implement the methods, systems, and apparatus for Uu-based sidelink control for NR V2X as disclosed herein. For example, Fig. 9A The WTRU 102g shown in FIG. 1 may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114c, which may employ an IEEE 802 radio technology.

[0550] Although not in Fig. 9A106 / 107 / 109. It will be appreciated that many of the concepts contained herein are equally applicable to UEs that are WTRUs and UEs that connect to the network using a wired connection. For example, concepts applied to wireless interfaces 115, 116, 117, and 115c / 116c / 117c are equally applicable to wired connections.

[0551] Fig. 9B 1 is a system diagram of an exemplary RAN 103 and a core network 106 that may implement the methods, systems, and apparatus for Uu-based sidelink control for NR V2X as discussed herein. As described above, the RAN 103 may employ a UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 115. The RAN 103 may also be in communication with the core network 106. Fig. 9B As shown in FIG. 1 , the RAN 103 may include Node-Bs 140a, 140b, and 140c, each of which may include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 115. Each of the Node-Bs 140a, 140b, and 140c may be associated with a particular cell (not shown) within the RAN 103. The RAN 103 may also include RNCs 142a, 142b. It will be appreciated that the RAN 103 may include any number of Node-Bs and radio network controllers (RNCs).

[0552] like Fig. 9B As shown in , Node-B 140a, 140b can communicate with RNC 142a. In addition, Node-B 140c can communicate with RNC142b. Node-B 140a, 140b and 140c can communicate with each RNC 142a and 142b via Iub interface. RNC 142a and 142b can communicate with each other via Iur interface. Each of RNC 142a and 142b can be configured to control each Node-B 140a, 140b and 140c it is connected to. In addition, each of RNC 142a and 142b can be configured to perform or support other functions, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro diversity, security function, data encryption, etc.

[0553] Fig. 9BThe core network 106 shown in FIG. 1 may include a media gateway (MGW) 144, a mobile switching center (MSC) 146, a serving GPRS support node (SGSN) 148, or a gateway GPRS support node (GGSN) 150. Although each of the foregoing elements is described as part of the core network 106, it will be understood that any of these elements may be owned or operated by an entity other than the core network operator.

[0554] The RNC 142a in the RAN 103 may be connected to the MSC 146 in the core network 106 via an IuCS interface. The MSC 146 may be connected to the MGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102a, 102b, and 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, and 102c and traditional land-line communications devices.

[0555] The RNC 142a in the RAN 103 may also be connected to the SGSN 148 in the core network 106 via an IuPS interface. The SGSN 148 may be connected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide the WTRUs 102a, 102b, and 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, and 102c and IP-enabled devices.

[0556] The core network 106 may also be connected to other networks 112, which may include other wired or wireless networks owned or operated by other service providers.

[0557] Fig. 9C 1 is a system diagram of an exemplary RAN 104 and a core network 107 that may implement the methods, systems, and apparatus for Uu-based sidelink control for NR V2X as discussed herein. As described above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 116. The RAN 104 may also be in communication with the core network 107.

[0558] The RAN 104 may include eNode-Bs 160a, 160b, and 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs. Each of the eNode-Bs 160a, 160b, and 160c may include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. For example, the eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0559] Each of the eNode-Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink or downlink, etc. Fig. 9C As shown in FIG. , eNode-Bs 160a , 160b , and 160c may communicate with each other via an X2 interface.

[0560] Fig. 9C The core network 107 shown in FIG. 1 may include a mobility management gateway (MME) 162, a serving gateway 164, and a packet data network (PDN) gateway 166. Although each of the foregoing elements is described as being part of the core network 107, it will be appreciated that any of these elements may be owned or operated by an entity other than the core network operator.

[0561] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial connection of the WTRUs 102a, 102b, and 102c, etc. The MME 162 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

[0562] The serving gateway 164 may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via an S1 interface. The serving gateway 164 may generally route and forward user packets to / from the WTRUs 102a, 102b, and 102c. The serving gateway 164 may also perform other functions, such as anchoring the user plane during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, and 102c, managing and storing contexts of the WTRUs 102a, 102b, and 102c, and the like.

[0563] The serving gateway 164 may also be connected to the PDN gateway 166, which may provide the WTRUs 102a, 102b, and 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0564] The core network 107 may facilitate communications with other networks. For example, the core network 107 may provide the WTRUs 102a, 102b, and 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, and 102c and traditional land-line communications devices. For example, the core network 107 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the core network 107 and the PSTN 108. In addition, the core network 107 may provide the WTRUs 102a, 102b, and 102c with access to the networks 112, which may include other wired or wireless networks owned or operated by other service providers.

[0565] Fig.9D 1 is a system diagram of an exemplary RAN 105 and a core network 109 that may implement the methods, systems, and apparatus for Uu-based sidelink control for NR V2X as disclosed herein. The RAN 105 may communicate with the WTRUs 102a and 102b over the air interface 117 using NR radio technology. The RAN 105 may also communicate with the core network 109. A non-3GPP interworking function (N3IWF) 199 may communicate with the WTRU 102c over the air interface 198 using a non-3GPP radio technology. The N3IWF 199 may also communicate with the core network 109.

[0566] The RAN 105 may include gNode-Bs 180a and 180b. It will be appreciated that the RAN 105 may include any number of gNode-Bs. Each of the gNode-Bs 180a and 180b may include one or more transceivers for communicating with the WTRUs 102a and 102b via the air interface 117. When an integrated access and backhaul connection is used, the same air interface may be used between the WTRUs and the gNode-Bs, which may be the core network 109 via one or more gNBs. The gNode-Bs 180a and 180b may implement MIMO, MU-MIMO, or digital beamforming techniques. Thus, the gNode-B 180a may, for example, use multiple antennas to send wireless signals to and receive wireless signals from the WTRU 102a. It will be appreciated that the RAN 105 may employ other types of base stations, such as an eNode-B. It will also be appreciated that the RAN 105 may employ more than one type of base station. For example, the RAN may employ both eNode-Bs an...

Claims

1. A first wireless transmit / receive unit WTRU comprising a processor, the processor being configured to: receiving a radio resource control, RRC, message, the RRC message comprising an indication of a sidelink radio network temporary identifier, SL-RNTI; receiving downlink control information (DCI) from a base station using the SL-RNTI, the DCI indicating a resource assignment for a physical sidelink shared channel (PSSCH) transmission to at least a second WTRU, wherein the DCI indicates a time for a first WTRU to send hybrid automatic repeat request (HARQ) feedback associated with the PSSCH transmission to the base station and resources for the first WTRU to send HARQ feedback associated with the PSSCH transmission to the base station; sending sidelink control information (SCI) to at least a second WTRU based on the DCI, the SCI indicating resource allocation for PSSCH transmission; sending the PSSCH to a second WTRU according to the SCI; receiving HARQ feedback for the PSSCH transmission from a second WTRU; as well as The HARQ feedback received from the second WTRU is sent to the base station according to the time and resources indicated in the DCI.

2. The first WTRU of claim 1, wherein resources used by the first WTRU to send HARQ feedback associated with PSSCH transmission to a base station correspond to physical uplink control channel (PUCCH) resources indicated in the RRC message.

3. The first WTRU of claim 1 , wherein the SCI comprises a time resource assignment field and a frequency assignment field.

4. The first WTRU of claim 1 , wherein the DCI includes an indication of a HARQ process used for PSSCH transmission.

5. The first WTRU of claim 1 , wherein the RRC message indicates that the PSCCH transmission corresponds to a unicast transmission.

6. The first WTRU according to claim 1, wherein the RRC message includes configuration information associated with multiple PUCCH resources for feeding back HARQ side link feedback to a base station, the configuration information indicates corresponding frequency information of each of the multiple PUCCH resources, and the RRC message indicates a corresponding index of each of the multiple PUCCH resources.

7. The first WTRU according to claim 6, wherein resources used by the first WTRU to send HARQ feedback associated with PSSCH transmission to the base station are indicated in the DCI using a corresponding index of one of the multiple PUCCH resources.

8. A method implemented by a first wireless transmit / receive unit WTRU, the method comprising: receiving a radio resource control, RRC, message, the RRC message comprising an indication of a sidelink radio network temporary identifier, SL-RNTI; receiving downlink control information (DCI) from a base station using the SL-RNTI, the DCI indicating a resource assignment for a physical sidelink shared channel (PSSCH) transmission to at least a second WTRU, wherein the DCI indicates a time for a first WTRU to send hybrid automatic repeat request (HARQ) feedback associated with the PSSCH transmission to the base station and resources for the first WTRU to send HARQ feedback associated with the PSSCH transmission to the base station; sending sidelink control information (SCI) to at least a second WTRU based on the DCI, the SCI indicating resource allocation for PSSCH transmission; sending the PSSCH to a second WTRU according to the SCI; receiving HARQ feedback for the PSSCH transmission from a second WTRU; as well as The HARQ feedback received from the second WTRU is sent to the base station according to the time and resources indicated in the DCI.

9. The method of claim 8, wherein resources used by the first WTRU to send HARQ feedback associated with the PSSCH transmission to the base station correspond to physical uplink control channel (PUCCH) resources indicated in the RRC message.

10. The method according to claim 8, wherein: The SCI includes a time resource allocation field and a frequency allocation field.

11. The method of claim 8, wherein the DCI includes an indication of a HARQ process used for PSSCH transmission.

12. The method according to claim 8, wherein: The RRC message indicates that the PSCCH transmission corresponds to a unicast transmission.

13. The method according to claim 8, wherein: The RRC message includes configuration information associated with multiple PUCCH resources used to feed back HARQ side link feedback to the base station, the configuration information indicates corresponding frequency information of each of the multiple PUCCH resources, and the RRC message indicates a corresponding index of each of the multiple PUCCH resources.

14. The method of claim 13, wherein resources for the first WTRU to send HARQ feedback associated with PSSCH transmission to the base station are indicated in the DCI using a corresponding index of one of the multiple PUCCH resources.

15. A base station comprising a processor, the processor being configured to: transmitting a radio resource control (RRC) message to a first wireless transmit / receive unit (WTRU), the RRC message including an indication of a sidelink radio network temporary identifier (SL-RNTI); transmitting downlink control information (DCI) to the WTRU using the SL-RNTI, the DCI indicating a resource assignment for a physical sidelink shared channel (PSSCH) transmission to be transmitted by the first WTRU to at least a second WTRU, wherein the DCI indicates a time for the first WTRU to send hybrid automatic repeat request (HARQ) feedback associated with the PSSCH transmission to a base station and resources for the first WTRU to send HARQ feedback associated with the PSSCH transmission to the base station, HARQ feedback is received from the first WTRU according to the time and resource indicated in the DCI, the HARQ feedback corresponding to the HARQ feedback received by the first WTRU from the second WTRU for the PSSCH transmission.

16. The base station of claim 15, wherein resources used by the first WTRU to send HARQ feedback associated with PSSCH transmission to the base station correspond to Physical Uplink Control Channel (PUCCH) resources indicated in the RRC message.

17. The base station of claim 15, wherein the DCI includes an indication of a HARQ process used for the PSSCH transmission.

18. The base station according to claim 15, wherein: The RRC message indicates that the PSCCH transmission corresponds to a unicast transmission.

19. The base station according to claim 15, wherein: The RRC message includes configuration information associated with multiple PUCCH resources used to feed back HARQ side link feedback to the base station, the configuration information indicates corresponding frequency information of each of the multiple PUCCH resources, and the RRC message indicates a corresponding index of each of the multiple PUCCH resources.

20. The base station of claim 19, wherein resources for the first WTRU to send HARQ feedback associated with a PSSCH transmission to the base station are indicated in the DCI using a corresponding index of one of the plurality of PUCCH resources.

21. A wireless transmit / receive unit WTRU comprising a processor, the processor being configured to: receiving a radio resource control (RRC) message including an indication of non-contiguous frequency resources for sidelink transmission, wherein: The non-contiguous frequency resources are allocated using a bitmap; sending side link control information SCI on the non-contiguous frequency resources according to the RRC message; receiving downlink control information DCI from a base station, wherein the DCI comprises a time domain resource assignment for a sidelink transmission, wherein the time domain resource comprises at least one of a physical sidelink control channel PSCCH or a physical sidelink shared channel PSSCH; dividing the time domain resource into a plurality of parts to allocate the parts of the time domain resource to a plurality of beam directions during beam scanning; and The side link transmission is performed using beam scanning across the non-contiguous frequency resources, wherein the beam is autonomously determined by the WTRU based on the configuration.

22. The WTRU of claim 21, wherein the processor is configured to receive scheduling downlink control information (DCI) indicating an amount of beam scanning required for a sidelink transmission.

23. The WTRU of claim 21, wherein the non-contiguous frequency resources are allocated using a bitmap, wherein the bitmap indicates frequency resources used for sidelink transmissions within a configured range.

24. The WTRU of claim 21, wherein the DCI comprises a time domain resource assignment for at least one of a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).

25. A WTRU according to claim 21, wherein the sidelink transmission is performed on a shared sidelink carrier between Uu communication and sidelink communication, wherein the sidelink transmission uses symbols marked for sidelink transmission having a time slot format indicated by a time slot format indicator SFI.

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