Channel access mechanisms for unlicensed sidelink communications

Abstract

To provide apparatus and methods for channel access in an unlicensed sidelink communication system.SOLUTION: In a communication system 100, a first UE triggers a listen-before-talk (LBT) process requesting to access first resources for transmission of data to a base station (BS), or reception of data from the BS. In response to the LBT, the first UE receives a first grant that indicates the first resources for the transmission of data to the BS, or reception of data from the BS. The first UE receives from one or more UEs which are in a first set, in which the first set of UEs are in communication range of the first UE, requests to access second resources for transmission or reception of data between the first UE, and the one or more UEs in the first set. The first UE transmits grants of the second resources, to the one or more UEs of the first set. The second resources include the remaining part of the first resources not used by the first UE.SELECTED DRAWING: Figure 1

Description

[Brief description of the drawings]

[0001] [Figure 1] FIG. 1 illustrates an example of a mobile communication system in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 2A] 2A and 2B illustrate example radio protocol stacks for the user plane and control plane, respectively, in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 2B] 2A and 2B illustrate example radio protocol stacks for the user plane and control plane, respectively, in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 3A] 3A, 3B, and 3C illustrate example mappings between logical channels and transport channels in the downlink, uplink, and sidelink, respectively, in accordance with some aspects of various example embodiments of the present disclosure. [Figure 3B] 3A, 3B, and 3C illustrate example mappings between logical channels and transport channels in the downlink, uplink, and sidelink, respectively, in accordance with some aspects of various example embodiments of the present disclosure. [Figure 4A] 4A, 4B, and 4C illustrate example mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, in accordance with some aspects of various example embodiments of the present disclosure. [Figure 4B] 4A, 4B, and 4C illustrate example mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, in accordance with some aspects of various example embodiments of the present disclosure. [Figure 4C]4A, 4B, and 4C illustrate example mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, in accordance with some aspects of various example embodiments of the present disclosure. [Diagram 5] 5A, 5B, 5C, and 5D illustrate example radio protocol stacks for NR sidelink communications in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 6] FIG. 6 illustrates example physical signals in the downlink, uplink and sidelink in accordance with some aspects of various example embodiments of the present disclosure. [Figure 7] FIG. 7 illustrates examples of Radio Resource Control (RRC) states and transitions between different RRC states in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 8] FIG. 8 illustrates an example frame structure and physical resources in accordance with some aspects of various example embodiments of the present disclosure. [Figure 9] FIG. 9 illustrates example component carrier configurations in different carrier aggregation scenarios in accordance with some aspects of various example embodiments of the present disclosure. [Figure 10A] FIG. 10A illustrates an example of channel occupation time (COT) sharing between a relay user equipment (UE) and a remote UE in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 10B] FIG. 10B illustrates an example of COT sharing between a relay UE and one or more remote UEs in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 10C] FIG. 10C illustrates an example of COT sharing between a remote UE and one UE in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 10D]FIG. 10D illustrates an example of COT sharing between a remote UE and one or more remote UEs in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 11] FIG. 11 illustrates an example illustrating COT resources in the time domain in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 12] FIG. 12 illustrates an example illustrating COT resources in the time domain and the frequency domain in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 13] FIG. 13 illustrates an example of COT sharing in a sidelink (SL) communication system having interference measurement capabilities to limit collisions in channel access in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 14] FIG. 14 illustrates example components of a UE for transmitting and / or receiving in accordance with some aspects of various example embodiments of the present disclosure. [Figure 15] FIG. 15 illustrates example components of a base station (BS) for transmission and / or reception in accordance with some aspects of various example embodiments of the present disclosure. [Figure 16] FIG. 16 illustrates a flow diagram illustrating a COT sharing method performed by a relay UE in accordance with some aspects of various example embodiments of the present disclosure. [Figure 17] FIG. 17 illustrates a flow diagram illustrating a COT sharing method performed by a remote UE in accordance with some aspects of various exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0002] 1 illustrates an example of a mobile communication system 100 according to some aspects of various exemplary embodiments of the present disclosure. The mobile communication system 100 may be operated by a wireless communication system operator, such as a Mobile Network Operator (MNO), a private network operator, a Multiple System Operator (MSO), an Internet of Things (IOT) network operator, etc., and may provide services such as voice, data (e.g., wireless Internet access), messaging, vehicular communication services such as Vehicle to Everything (V2X) communication services, safety services, mission critical services, IOT, services in residential, commercial or industrial environments such as Industrial IOT (IIOT), etc.

[0003] The mobile communication system 100 may enable various types of applications having different requirements in terms of latency, reliability, throughput, etc. Exemplary supported applications include enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), and massive machine type communications (mMTC), where eMBB may support high peak data rates as well as stable connections at moderate rates for cell edge users. URLLC may support applications with stringent requirements in terms of latency and reliability and moderate requirements in terms of data rates. Exemplary mMTC applications include networks of vast numbers of IoT devices that are only sporadically active and transmit small data payloads.

[0004] The mobile communication system 100 may include a radio access network (RAN) portion and a core network portion. The example shown in FIG. 1 illustrates a Next Generation RAN (NG-RAN) 105 and a 5G core network (5g-CN) 110 as examples of the RAN and the core network, respectively. Other examples of the RAN and the core network may be implemented without departing from the scope of the present disclosure. Other examples of the RAN include an Evolved Universal Terrestrial Radio Access Network (EUTRAN), a Universal Terrestrial Radio Access Network (UTRAN), and the like. Other examples of the core network include an Evolved Packet Core (EPC), a UMTS Core Network (UCN), and the like. The RAN implements a radio access technology (RAT) and resides between a user equipment (UE) 125 and the core network, and FIG. 14 illustrates an example of a SL resource allocation process with preemption for aperiodic traffic according to some aspects of various exemplary embodiments of the present disclosure. Examples of such RATs include New Radio (NR), Long Term Evolution (LTE), also known as Evolved Universal Terrestrial Radio Access (EUTRA), Universal Mobile Telecommunication System (UMTS), etc. The RAT of the exemplary mobile communication system 100 may be NR. The core network exists between the RAN and one or more external networks (e.g., data networks) and is responsible for functions such as mobility management, authentication, session management, bearer setup, and application of different quality of service (QoS). The functional layer between the UE 125 and the RAN (e.g., NG-RAN 105) may be referred to as the access stratum (AS), and the functional layer between the UE 125 and the core network (e.g., 5G-CN 110) may be referred to as the non-access stratum (NAS).

[0005] The UE 125 may include wireless transmitting and receiving means for communicating with one or more nodes of the RAN, one or more relay nodes, or one or more other UEs, etc. Examples of a UE include, but are not limited to, a smartphone, a tablet, a laptop, a computer, a wireless transmitting and / or receiving unit in a vehicle, a V2X or vehicle-to-vehicle (V2V) device, a wireless sensor, an IoT device, an IIOT device, etc. Other names may be used for a UE, such as a mobile station (MS), terminal equipment, terminal node, client device, mobile device, etc.

[0006] The RAN may include nodes (e.g., base stations) for communication with UEs. For example, the NG-RAN 105 of the mobile communication system 100 may comprise nodes for communication with the UE 125. Different names for the RAN nodes may be used depending, for example, on the RAT used for the RAN. The RAN nodes may be referred to as Node Bs (NBs) in a RAN using the UMTS RAT. The RAN nodes may be referred to as Evolved Node Bs (eNBs) in a RAN using the LTE / EUTRA RAT. In the illustrative example of the mobile communication system 100 of FIG. 1, the nodes of the NG-RAN 105 may be either Next Generation Node Bs (gNBs) 115 or Next Generation Evolved Node Bs (ng-eNBs) 120. In this specification, the terms base station, RAN node, gNB, and ng-eNB may be used interchangeably. The gNBs 115 may provide NR user plane protocol terminations and control plane protocol terminations towards the UE 125. The ng-eNBs 120 may provide E-UTRA user plane protocol terminations and control plane protocol terminations towards the UE 125. The interface between the gNB 115 and the UE 125 or the interface between the ng-eNB 120 and the UE 125 may be referred to as a Uu interface. The Uu interface may be established with a user plane protocol stack and a control plane protocol stack. For the Uu interface, the direction from the base station (e.g., gNB 115 or ng-eNB 120) to the UE 125 may be referred to as a downlink, and the direction from the UE 125 to the base station (e.g., gNB 115 or ng-eNB 120) may be referred to as an uplink.

[0007] The gNB 115 and the ng-eNB 120 may be interconnected with each other by an Xn interface. The Xn interface may comprise an Xn User Plane (Xn-U) interface and an Xn Control Plane (Xn-C) interface. The transport network layer of the Xn-U interface may be built on Internet Protocol (IP) transport, and GPRS Tunneling Protocol (GTP) may be used on top of User Datagram Protocol (UDP) / IP to carry user plane protocol data units (PDUs). Xn-U may provide non-guaranteed delivery of user plane PDUs and may support data forwarding and flow control. The transport network layer of the Xn-C interface may be built on Stream Control Transport Protocol (SCTP) on top of IP. The application layer signaling protocol may be referred to as Xn Application Protocol (XnAP). The SCTP layer may provide guaranteed delivery of application layer messages. At the transport IP layer, point-to-point transmission may be used to deliver the signaling PDUs. The Xn-C interface may support Xn interface management, UE mobility management including context transfer and RAN paging, and dual connectivity.

[0008] The gNB 115 and the ng-eNB 120 may also be connected to the 5GC 110 by an NG interface, more specifically to the Access and Mobility Management Function (AMF) 130 of the 5GC 110 by an NG-C interface, and to the User Plane Function (UPF) 135 of the 5GC 110 by an NG-U interface. The transport network layer of the NG-U interface may be built on IP transport, and the GTP protocol may be used on top of UDP / IP to carry user plane PDUs between the NG-RAN nodes (e.g., the gNB 115 or the ng-eNB 120) and the UPF 135. The NG-U may provide non-guaranteed delivery of user plane PDUs between the NG-RAN nodes and the UPF. The transport network layer of the NG-C interface may be built on IP transport. SCTP may be added on top of IP for reliable transport of signaling messages. The application layer signaling protocol may be referred to as NG Application Protocol (NGAP). The SCTP layer can provide guaranteed delivery of application layer messages. For transport, IP layer point-to-point transmission can be used to deliver signaling PDUs. The NG-C interface can provide the following functions: NG interface management, UE context management, UE mobility management, transport of NAS messages, paging, PDU session management, configuration transfer, and alert message transmission.

[0009] The gNB 115 or ng-eNB 120 may host one or more of the following functions: radio bearer control, radio admission control, connection mobility control, radio resource management functions such as dynamic allocation of resources (e.g., scheduling) to UEs in both uplink and downlink, IP and Ethernet header compression, data encryption and integrity protection, selection of AMF at UE attachment in the absence of routing to AMF may be determined from information provided by the UE, routing of user plane data towards UPF, routing of control plane information towards AMF, connection setup and release, scheduling of paging messages and and transmission, scheduling and transmission of system broadcast information (e.g. originated from the AMF), measurement and measurement reporting configuration for mobility and scheduling, transport level packet marking in the uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UEs in RRC inactive state, distribution function for NAS messages, radio access network sharing, dual connectivity, close interaction between NR and E-UTRA, as well as maintaining security and radio configuration for User Plane 5G System (5GS) Cellular IoT (CIoT) optimization.

[0010] The AMF 130 may host one or more of the following functions: NAS signaling termination, NAS signaling security, AS security control, CN inter-node signaling for mobility between 3GPP access networks, idle mode UE reachability (including control and execution of paging retransmissions), registration area management, support for intra-system and inter-system mobility, access authentication, access authorization including validation of roaming rights, mobility management control (subscription and policy), support for network slicing, Session Management Function (SMF) selection, 5GS CIoT optimization selection.

[0011] The UPF 135 may host one or more of the following functions: anchor point for intra / inter-RAT mobility (where applicable), interconnection of external PDU session points to the data network, packet routing and forwarding, packet inspection and user plane part of policy rule enforcement, traffic usage reporting, uplink classifier supporting routing of traffic flows to the data network, support for multi-homed PDU sessions with branching points, QoS processing for the user plane, e.g., packet filtering, gating, UL / DL rate enforcement, uplink traffic validation (mapping of Service Data Flows (SDF) to QoS flows), downlink packet buffering and downlink data notification triggering.

[0012] As shown in FIG. 1, the NG-RAN 105 may support a PC5 interface between two UEs 125 (e.g., UE 125A and UE 125B). In the PC5 interface, the direction of communication between two UEs (e.g., from UE 125A to UE 125B or vice versa) may be referred to as a sidelink. Sidelink transmission and reception over the PC5 interface may be supported when the UE 125 is inside the NG-RAN 105 coverage and when the UE 125 is outside the NG-RAN 105 coverage, regardless of which RRC state the UE is in. Support for V2X services over the PC5 interface may be provided by NR sidelink communication and / or V2X sidelink communication.

[0013] PC5-S signaling may be used for unicast link establishment with a Direct Communication Request / Accept message. A UE may self-assign its source Layer 2 ID for a PC5 unicast link, for example, based on the V2X service type. During the unicast link establishment procedure, a UE may send its source Layer 2 ID for a PC5 unicast link to a peer UE, for example, a UE from which a destination ID was received from a higher layer. The pair of source Layer 2 ID and destination Layer 2 ID may uniquely identify a unicast link. The receiving UE may verify that the destination ID belongs to it and may acknowledge the unicast link establishment request from the source UE. During the PC5 unicast link establishment procedure, PC5-RRC procedures on the access stratum may be invoked for the purpose of UE sidelink context establishment as well as for AS layer configuration, capability exchange, etc. PC5-RRC signaling may enable the exchange of UE capabilities and AS layer configuration, such as sidelink radio bearer configuration, between a pair of UEs between which a PC5 unicast link is established.

[0014] NR sidelink communication may support one of three types of transmission modes (e.g., unicast transmission, groupcast transmission, and broadcast transmission) for a pair of source Layer 2 ID and destination Layer 2 ID in an AS. The unicast transmission mode may be characterized by the support of one PC5-RRC connection between peer UEs for the pair, the transmission and reception of control information and user traffic between peer UEs in the sidelink, the support of sidelink HARQ feedback, the support of sidelink transmit power control, the support of RLC acknowledged mode (AM), and the detection of radio link failure for the PC5-RRC connection. The groupcast transmission may be characterized by the transmission and reception of user traffic between UEs belonging to a group in the sidelink, and the support of sidelink HARQ feedback. The broadcast transmission may be characterized by the transmission and reception of user traffic between UEs in the sidelink.

[0015] The source Layer 2 ID, destination Layer 2 ID, and PC5 link identifier may be used for NR sidelink communications. The source Layer 2 ID may identify the sender of the data in the NR sidelink communications. The source Layer 2 ID may be 24 bits long and may be split into two bit strings at the MAC layer, one bit string being the LSB portion (8 bits) of the source Layer 2 ID and forwarded to the physical layer of the sender. This may identify the source of the intended data in the sidelink control information and may be used for filtering the packets at the physical layer of the receiver, and the second bit string may be the MSB portion (16 bits) of the source Layer 2 ID and may be carried in a medium access control (MAC) header. This may be used for filtering the packets at the MAC layer of the receiver. The destination Layer 2 ID may identify the target of the data in the NR sidelink communications. For NR sidelink communications, the destination Layer 2 ID may be 24 bits long and may be split into two bit strings at the MAC layer, one bit string being the LSB portion (16 bits) of the destination Layer 2 ID and forwarded to the physical layer of the sender. This may identify the intended target of data in the sidelink control information and may be used for filtering packets at the receiver's physical layer, and the second bit string may be the MSB part (8 bits) of the destination Layer 2 ID and may be carried in the MAC header. This may be used for filtering packets at the receiver's MAC layer. The PC5 link identifier may uniquely identify a PC5 unicast link at the UE for the lifetime of the PC5 unicast link. The PC5 link identifier may be used to indicate the PC5 unicast link for which a sidelink Radio Link Failure (RLF) declaration has been made and the PC5-RRC connection has been released.

[0016] 2A and 2B illustrate examples of radio protocol stacks for the user plane and control plane, respectively, according to some aspects of various exemplary embodiments of the present disclosure. As shown in FIG. 2A, the protocol stack for the user plane of the Uu interface (between the UE 125 and the gNB 115) includes Service Data Adaptation Protocol (SDAP) 201 and SDAP 211, Packet Data Convergence Protocol (PDCP) 202 and PDCP 212, Radio Link Control (RLC) 203, RLC 213, MAC 204 and MAC 214 sublayers of Layer 2, and Physical (PHY) 205 and PHY 215 layers (Layer 1 is also referred to as L1).

[0017] The PHY 205 and PHY 215 provide transport channels 244 to the MAC 204 and MAC 214 sublayers. The MAC 204 and MAC 214 sublayers provide logical channels 243 to the RLC 203 and RLC 213 sublayers. The RLC 203 and RLC 213 sublayers provide RLC channels 242 to the PDCP 202 and PCP 212 sublayers. The PDCP 202 and PDCP 212 sublayers provide radio bearers 241 to the SDAP 201 and SDAP 211 sublayers. The radio bearers can be classified into two groups: Data Radio Bearers (DRBs) for user plane data and Signaling Radio Bearers (SRBs) for control plane data. The SDAP 201 and SDAP 211 sublayers provide QoS flows 240-5GC.

[0018] The main services and functions of the MAC204 or MAC214 sublayer include: mapping between logical channels and transport channels, multiplexing / demultiplexing of MAC Service Data Units (SDUs) belonging to one or more logical channels to / from Transport Blocks (TBs) delivered to / from the physical layer on transport channels, scheduling information reporting, error correction with Hybrid Automatic Repeat Request (HARQ) (one HARQ entity per cell in case of Carrier Aggregation (CA)), priority handling between UEs with dynamic scheduling, priority handling between logical channels of one UE with Logical Channel Prioritization (LCP), priority handling between overlapped resources of one UE, and padding. A single MAC entity can support multiple numerologies, transmission timings, and cells. Mapping constraints in logical channel prioritization control which numerologies, cells, and transmission timings a logical channel can use.

[0019] The HARQ function can ensure delivery between peer entities at Layer 1. A single HARQ process can support one TB when the physical layer is not configured for downlink / uplink spatial multiplexing, and a single HARQ process can support one or more TB when the physical layer is configured for downlink / uplink spatial multiplexing.

[0020] The RLC203 or RLC213 sublayer can support three transmission modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC configuration can be per logical channel, independent of numerology and / or transmission duration, and the Automatic Repeat Request (ARQ) can operate for any of the numerologies and / or transmission durations for which the logical channel is configured.

[0021] The main services and functions of the RLC203 or RLC213 sublayer depend on the transmission mode (e.g., TM, UM, or AM) and may include the following: transfer of higher layer PDUs, sequence numbering independent of the sequence numbering in PDCP (UM and AM), error correction via ARQ (AM only), segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs, re-assembly (AM and UM), duplicate detection (AM only), RLC SDU discard (AM and UM), RLC re-establishment, and protocol error detection (AM only).

[0022] The automatic repeat request in the RLC203 or RLC213 sublayer may have the following properties: ARQ retransmits RLC SDUs or RLC SDU segments based on an RLC status report; it may be used when polling for an RLC status report is required by RLC; the RLC receiver may also trigger an RLC status report after detecting a lost RLC SDU or RLC SDU segment.

[0023] The main services and functions of the PDCP202 or PDCP212 sublayer may include: forwarding of data (user plane or control plane), maintenance of the PDCP sequence number (SN), header compression and decompression using the Robust Header Compression (ROHC) protocol, header compression and decompression using the EHC protocol, encryption and decryption, integrity protection and integrity verification, timer-based SDU discard, routing for split bearers, duplication, re-ordering and in-order delivery, out-of-order delivery, and duplicate discard.

[0024] The main services and functions of the SDAP 201 or SDAP 211 include mapping between QoS flows and data radio bearers, and marking QoS Flow ID (QFI) in both downlink and uplink packets. A single protocol entity of the SDAP can be configured for each individual PDU session.

[0025] As shown in FIG. 2B, the control plane protocol stack of the Uu interface (between UE 125 and gNB 115) includes a PHY layer (Layer 1), Layer 2 MAC, RLC, and PDCP sublayers as described above, plus the RRC 206 and RRC 216 sublayers. The main services and functions of the RRC206 and RRC216 sublayers on the Uu interface include broadcasting of system information regarding AS and NAS, paging initiated by 5GC or NG-RAN, establishment, maintenance and release of RRC connection between UE and NG-RAN (including adding, modifying and releasing carrier aggregation, and adding, modifying and releasing dual connectivity in NR or between E-UTRA and NR), security functions including management of keys, establishment, configuration, maintenance and release of SRBs and DRBs, mobility functions (including handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, and inter-RAT mobility), QoS management functions, control of UE measurement and reporting, detection and recovery of radio link failure, and forwarding of NAS messages to / from the UE to / from the NAS. The NAS207 and NAS227 layers are control protocols (terminated in the AMF on the network side) that perform functions such as authentication, mobility management, security control, etc.

[0026] Sidelink specific services and functions of the RRC sublayer over the Uu interface include: configuration of sidelink resource allocation via system information or dedicated signaling, reporting of UE sidelink information, sidelink related measurement configuration and reporting, and reporting of UE assistance information for SL traffic patterns.

[0027] 3A, 3B, and 3C show example mappings between logical channels and transport channels in the downlink, uplink, and sidelink, respectively, according to some aspects of various example embodiments of the present disclosure. Different types of data transfer services may be provided by the MAC. Each logical channel type may be defined by what type of information is transferred. The logical channels may be classified into two groups: control channels and traffic channels. The control channels may be used for transfer of control plane information only. The Broadcast Control Channel (BCCH) is a downlink channel for broadcasting system control information. The Paging Control Channel (PCCH) is a downlink channel that carries paging messages. The Common Control Channel (CCCH) is a channel for transmitting control information between the UE and the network. This channel may be used for UEs that do not have an RRC connection with the network. The Dedicated Control Channel (DCCH) is a point-to-point bidirectional channel that transmits dedicated control information between the UE and the network and may be used by UEs that have an RRC connection. The traffic channels may be used for transfer of user plane information only. A Dedicated Traffic Channel (DTCH) is a point-to-point channel dedicated to one UE for the transfer of user information. A DTCH can exist in both the uplink and downlink. A Sidelink Control Channel (SCCH) is a sidelink channel for transmitting control information (e.g., PC5-RRC and PC5-S messages) from one UE to another. A Sidelink Traffic Channel (STCH) is a sidelink channel for transmitting user information from one UE to another. A Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel for broadcasting sidelink system information from one UE to other UEs.

[0028] Downlink transport channel types include the Broadcast Channel (BCH), the Downlink Shared Channel (DL-SCH), and the Paging Channel (PCH). The BCH may be characterized by a fixed, predefined transport format and a requirement to broadcast in the entire coverage area of ​​a cell, either as a single message or by beamforming different BCH instances. The DL-SCH may be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding and transmit power, the possibility of being broadcasted in the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE Discontinuous Reception (DRX) to enable UE power savings. The DL-SCH may be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding and transmit power, the possibility of being broadcasted in the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE Discontinuous Reception (DRX) to enable UE power savings. The PCH may be characterized by support for UE Discontinuous Reception (DRX) to enable UE power savings (DRX cycles are indicated to the UE by the network), a requirement to broadcast throughout the coverage area of ​​a cell either as a single message or by beamforming different BCH instances, and being mapped to physical resources that can be dynamically used for traffic / other control channels as well.

[0029] In the downlink, the following connections between logical channels and transport channels may exist: BCCH may be mapped to BCH, BCCH may be mapped to DL-SCH, PCCH may be mapped to PCH, CCCH may be mapped to DL-SCH, DCCH may be mapped to DL-SCH, and DTCH may be mapped to DL-SCH.

[0030] Uplink transport channel types include the Uplink Shared Channel (UL-SCH) and the Random Access Channel (RACH). The UL-SCH may be characterized by the possibility of using beamforming, support for dynamic link adaptation by varying the transmit power and potentially the modulation and coding, support for HARQ, support for both dynamic and semi-static resource allocation. The RACH may be characterized by limited control information, and collision risk.

[0031] In the uplink, the following connections between logical channels and transport channels may exist: CCCH may be mapped to UL-SCH, DCCH may be mapped to UL-SCH, and DTCH may be mapped to UL-SCH.

[0032] Sidelink transport channel types include a Sidelink Broadcast Channel (SL-BCH) and a Sidelink Shared Channel (SL-SCH). The SL-BCH may feature a predefined transport format. The SL-SCH may feature support for unicast, groupcast, and broadcast transmissions, support for both UE autonomous resource selection and scheduled resource allocation by the NG-RAN, support for both dynamic and semi-static resource allocation when the UE is assigned resources by the NG-RAN, support for HARQ, and support for dynamic link adaptation by varying transmit power, modulation, and coding.

[0033] In the sidelink, the following connections between logical channels and transport channels may exist: SCCH may be mapped to SL-SCH, STCH may be mapped to SL-SCH, and SBCCH may be mapped to SL-BCH.

[0034] 4A, 4B, and 4C show example mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, according to some aspects of various exemplary embodiments of the present disclosure. The downlink physical channels include a Physical Downlink Shared Channel (PDSCH), a Physical Downlink Control Channel (PDCCH), and a Physical Broadcast Channel (PBCH). The PCH, DL-SCH transport channel is mapped to the PDSCH. The BCH transport channel is mapped to the PBCH. The transport channels are not mapped to the PDCCH, but Downlink Control Information (DCI) is transmitted via the PDCCH.

[0035] The uplink physical channels include the Physical Uplink Shared Channel (PUSCH), the Physical Uplink Control Channel (PUCCH), and the Physical Random Access Channel (PRACH). The UL-SCH transport channel may be mapped to the PUSCH, and the RACH transport channel may be mapped to the PRACH. The transport channels are not mapped to the PUCCH, but the Uplink Control Information (UCI) is transmitted via the PUCCH.

[0036] The physical channels of the sidelink include the Physical Sidelink Shared Channel (PSSCH), the Physical Sidelink Control Channel (PSCCH), the Physical Sidelink Feedback Channel (PSFCH), and the Physical Sidelink Broadcast Channel (PSBCH). The Physical Sidelink Control Channel (PSCCH) may indicate the resources and other transmission parameters used by the UE for the PSSCH. The Physical Sidelink Shared Channel (PSSCH) may transmit TBs of the data itself, as well as control information for HARQ procedures and CSI feedback triggers, etc. At least six OFDM symbols in a slot may be used for PSSCH transmission. The Physical Sidelink Feedback Channel (PSFCH) may carry HARQ feedback over the sidelink from the UE that is the intended recipient of the PSSCH transmission to the UE that performed the transmission. The PSFCH sequence may be transmitted in one PRB that is repeated across two OFDM symbols near the end of the sidelink resources in the slot. The SL-SCH transport channel may be mapped to the PSSCH. The SL-BCH may be mapped to the PSBCH. The transport channel is not mapped to the PSFCH, but the sidelink feedback control information (SFCI) may be mapped to the PSFCH. The transport channel is not mapped to the PSCCH, but the sidelink control information (SCI) may be mapped to the PSCCH.

[0037] 5A, 5B, 5C, and 5D illustrate examples of radio protocol stacks for NR sidelink communications according to some aspects of various exemplary embodiments of the present disclosure. The AS protocol stack for the user plane (i.e., for STCH) in the PC5 interface may consist of SDAP, PDCP, RLC, and MAC sublayers, and a physical layer. The protocol stack of the user plane is shown in FIG. 5A. The AS protocol stack for the SBCCH in the PC5 interface may consist of RRC, RLC, MAC sublayers, and a physical layer, as shown below in FIG. 5B. To support the PC5-S protocol, PC5-S is placed above the PDCP, RLC, and MAC sublayers for SCCH for PC5-S, and a physical layer in the control plane protocol stack, as shown in FIG. 5C. The AS protocol stack for the control plane for SCCH for RRC in the PC5 interface consists of RRC, PDCP, RLC, and MAC sublayers, and a physical layer. The protocol stack of the control plane for SCCH for RRC is shown in FIG. 5D.

[0038] Sidelink Radio Bearers (SLRBs) may be classified into two groups: Sidelink Data Radio Bearers (SL DRBs) for user plane data and Sidelink Signaling Radio Bearers (SL SRBs) for control plane data. Separate SL SRBs using different SCCHs may be configured for PC5-RRC and PC5-S signaling, respectively.

[0039] The MAC sublayer can provide the following services and functions over the PC5 interface: radio resource selection, packet filtering, priority handling between uplink and sidelink transmissions for a given UE, and sidelink CSI reporting. Due to logical channel prioritization constraints in the MAC, only sidelink logical channels belonging to the same destination can be multiplexed into the MAC PDU for each unicast, groupcast, and broadcast transmission that may be associated with the destination. For packet filtering, a SL-SCH MAC header containing both source and destination Layer 2 ID parts may be added to the MAC PDU. A logical channel identifier (LCID) included within the MAC subheader can uniquely identify a logical channel within the scope of the source Layer 2 ID and destination Layer 2 ID combination.

[0040] The services and functions of the RLC sublayer may be supported for the sidelink. Both RLC Unacknowledged Mode (UM) and Acknowledged Mode (AM) may be used in unicast transmission, and only UM may be used in groupcast or broadcast transmission. In the case of UM, only unidirectional transmission may be supported for groupcast and broadcast.

[0041] The services and functions of the PDCP sublayer for the Uu interface may be supported for the sidelink with some restrictions, out-of-order delivery may be supported only for unicast transmission, and duplication may not be supported over the PC5 interface.

[0042] The SDAP sublayer may provide the following services and functions over the PC5 interface: Mapping between QoS flows and sidelink data radio bearers: There may be one SDAP entity per destination for one of unicast, groupcast, and broadcast associated with the destination.

[0043] The RRC sublayer may provide the following services and functions over the PC5 interface: forwarding of PC5-RRC messages between peer UEs, maintaining and releasing the PC5-RRC connection between two UEs, and detecting sidelink radio link failure for the PC5-RRC connection based on an indication from MAC or RLC. A PC5-RRC connection may be a logical connection between two UEs for a pair of source and destination Layer 2 IDs that may be considered to be established after a corresponding PC5 unicast link is established. There may be a one-to-one correspondence between PC5-RRC connections and PC5 unicast links. A UE may have multiple PC5-RRC connections with one or more UEs for different pairs of source Layer 2 IDs and destination Layer 2 IDs. Separate PC5-RRC procedures and messages may be used for a UE to forward sidelink configuration, including UE capabilities and SL-DRB configuration, to a peer UE. Both peer UEs may exchange their own UE capabilities and sidelink configuration using separate bidirectional procedures in both sidelink directions.

[0044] FIG. 6 illustrates example physical signals in the downlink, uplink, and sidelink according to some aspects of various example embodiments of the present disclosure. Demodulation reference signals (DM-RS) may be used in the downlink, uplink, and sidelink and may be used for channel estimation. DM-RS is a terminal-specific (UE-specific) reference signal that may be transmitted along with a physical channel in the downlink, uplink, or sidelink and may be used for channel estimation and coherent detection of the physical channel. Phase tracking reference signals (PT-RS) may be used in the downlink, uplink, and sidelink and may be used to track phase and mitigate performance loss due to phase noise. PT-RS may be primarily used to estimate and minimize the impact of common phase error (CPE) on system performance. Due to phase noise characteristics, PT-RS signals may have low density in the frequency domain and high density in the time domain. PT-RS may occur in combination with DM-RS and when the network configures PT-RS to be present. Positioning reference signals (PRS) may be used in the downlink for positioning using different positioning techniques. PRS may be used to measure the delay of downlink transmission by correlating the received signal from the base station with a local replica in the receiver. Channel state information reference signals (CSI-RS) may be used in the downlink and sidelink. CSI-RS may be used for channel state estimation, Reference Signal Received Power (RSRP) measurement for mobility and beam management, time / frequency tracking for demodulation, among other uses. CSI-RS may be configured UE-specific, but multiple users may share the same CSI-RS resource. UEs may determine CSI reports and transmit them in the uplink to the base station using PUCCH or PUSCH. CSI reports may be carried in the sidelink MAC CE. Primary synchronization signals (PSS) and secondary synchronization signals (SSS) may be used for radio frame synchronization. PSS and SSS may be used for cell search procedures during initial attach or for mobility purposes.A sounding reference signal (SRS) may be used in the uplink for uplink channel estimation. Similar to CSI-RS, the SRS may serve as a QCL reference for other physical channels so that they may be configured and transmitted quasi-colocated with the SRS. Sidelink PSS (S-PSS) and sidelink SSS (S-SSS) may be used in the sidelink for sidelink synchronization.

[0045] FIG. 7 illustrates an example frame structure and physical resources according to some aspects of various example embodiments of the present disclosure. Downlink or uplink or sidelink transmissions may be organized into frames with a duration of 10 ms consisting of ten 1 ms subframes. Each subframe may consist of one, two, four or more slots, and the number of slots per subframe may depend on the subcarrier spacing of the carrier on which the transmission takes place. The slot duration may be 14 symbols with normal cyclic prefix (CP) and 12 symbols with extended CP, and may scale in time as a function of the subcarrier spacing used such that there is an integer number of slots in a subframe. FIG. 7 illustrates a resource grid in the time and frequency domain. Each element of the resource grid, which comprises one symbol in time and one subcarrier in frequency, is referred to as a resource element (RE). A resource block (RB) may be defined as 12 consecutive subcarriers in the frequency domain.

[0046] In some examples, with non-slot-based scheduling, the transmission of a packet may occur over a portion of a slot, e.g., 2, 4, or 7 OFDM symbols, sometimes referred to as a minislot. Minislots may be used for low latency applications such as URLLC and operation in unlicensed bands. In some embodiments, minislots may also be used for fast flexible scheduling of services (e.g., preemption of URLLC over eMBB).

[0047] FIG. 8 illustrates example component carrier configurations in different carrier aggregation scenarios according to some aspects of various example embodiments of the present disclosure. In carrier aggregation (CA), two or more component carriers (CCs) may be aggregated. A UE may receive or transmit simultaneously on one or more CCs depending on its capabilities. CA may be supported for both contiguous and non-contiguous CCs in the same band or different bands as shown in FIG. 8. The gNB and UE may communicate using a serving cell. The serving cell may be associated with at least one downlink CC (e.g., may be associated with only one downlink CC or may be associated with a downlink CC and an uplink CC). The serving cell may be a primary cell (PCell) or a secondary c-cell (SCell).

[0048] The UE may adjust the timing of its uplink transmission using an uplink timing control procedure. A timing advance (TA) may be used to adjust the uplink frame timing relative to the downlink frame timing. The gNB may determine a desired timing advance setting and provide it to the UE. The UE may use the given TA to determine the UE's uplink transmission timing relative to the UE's observed downlink receive timing.

[0049] In the RRC connected state, the gNB may be responsible for maintaining the timing advance to keep L1 synchronized. Serving cells with uplinks to which the same timing advance is applied and using the same timing reference cell are grouped in a Timing Advance Group (TAG). A TAG may contain at least one serving cell with a configured uplink. The mapping of serving cells to TAGs may be configured by RRC. For a primary TAG, the UE may use the PCell as a timing reference cell, except for shared spectrum channel access, in which case the SCell may also be used as a timing reference cell in some cases. In a secondary TAG, the UE may use any of the activated SCells of this TAG as a timing reference cell and may not have to change it unless necessary.

[0050] Timing advance updates may be signaled by the gNB to the UE via a MAC CE command. Such a command may restart a TAG-specific timer that may indicate whether L1 may be synchronized or not; when the timer is running, L1 may be considered synchronized, otherwise L1 may be considered unsynchronized (in which case uplink transmissions may only be made on the PRACH).

[0051] A UE with a single timing advance capability for CA may simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into one TAG) sharing the same timing advance. A UE with multiple timing advance capabilities for CA may simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into multiple TAGs) with different timing advances. The NG-RAN may ensure that each TAG includes at least one serving cell. A non-CA capable UE may receive on a single CC and transmit on a single CC corresponding to only one serving cell (one serving cell in one TAG).

[0052] The multi-carrier nature of the physical layer in case of CA may be exposed to the MAC layer, and one HARQ entity may be required per serving cell. If CA is configured, the UE may have one RRC connection with the network. At RRC connection establishment / re-establishment / handover, one serving cell (e.g., PCell) may provide NAS mobility information. Depending on the UE capabilities, the SCell may be configured to form a set of serving cells together with the PCell. The configured set of serving cells for a UE may consist of one PCell and one or more SCells. Reconfiguration, addition, and removal of SCells may be done by RRC.

[0053] In a dual connectivity scenario, a UE may be configured with multiple cells comprising a master cell group (MCG) for communication with a master base station, a secondary cell group (SCG) for communication with a secondary base station, and two MAC entities: one MAC entity for the MCG for communication with the master base station and one MAC entity for the SCG for communication with the secondary base station.

[0054] FIG. 9 illustrates an example bandwidth portion configuration and switching according to some aspects of various example embodiments of the present disclosure. A UE may be configured with one or more bandwidth portions (BWPs) 910 on a given component carrier. In some examples, one of the one or more bandwidth portions may be active at a time. The active bandwidth portion may define the UE's operating bandwidth within the operating bandwidth of the cell. For initial access and until the UE's configuration in the cell is received, an initial bandwidth portion 920 determined from system information may be used. In bandwidth adaptation (BA), for example, through BWP switching 940, the UE's reception and transmission bandwidths may not be as large as the cell's bandwidth and may be adjusted. For example, the widths may be ordered to change (e.g., shrink during periods of low activity to save power), the location may move in the frequency domain (e.g., to increase scheduling flexibility), and the subcarrier spacing may be ordered to change (e.g., to enable different services). The first active BWP 920 may be the active BWP upon RRC (re)configuration for the PCell or activation of the SCell.

[0055] For a downlink BWP or uplink BWP in the set of downlink or uplink BWPs, respectively, the UE may be given the following configuration parameters: subcarrier spacing (SCS), cyclic prefix, common RBs and a number of consecutive RBs, index in the set of downlink or uplink BWPs by the respective BWP-Id, set of BWP common and set of BWP-specific parameters. A BWP may be associated with an OFDM numerology according to the configured subcarrier spacing and cyclic prefix for the BWP. For the serving cell, the UE may be provided with a default downlink BWP among the configured downlink BWPs. If the UE is not provided with a default downlink BWP, the default downlink BWP may be the initial downlink BWP.

[0056] A downlink BWP may be associated with a BWP inactivity timer. If a BWP inactivity timer associated with an active downlink BWP expires and if a default downlink BWP is configured, the UE may perform a BWP switch to the default BWP. If a BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is not configured, the UE may perform a BWP switch to the initial downlink BWP.

[0057] FIG. 10A illustrates an example of a sidelink communication scheme 1000 with resource sharing capability between a relay UE and a remote UE, according to some aspects of the disclosure. The scheme 1000 may be employed by UEs 125A-B in a network, such as the network 100, for sidelink communication. In particular, a sidelink UE may employ the scheme 1000 for transmission and reception of sidelink control information (SCI) and sidelink data over a forward / reverse sidelink link 1012. For example, a relay UE 1004 may transmit SCI / sidelink data to a remote UE 1006 over a forward link, and the remote UE 1006 may transmit SCI / sidelink data to the relay UE 1004 over a reverse link. In the scheme 1000, a relay UE 1004 that is within a coverage area of ​​a gNB 1002 and in communication with the gNB 1002 over a link 1010 may operate as a relay for the remote UE 1006. For example, the UE 1004 may relay DL SCI / data from the gNB 1002 to the UE 1006 via link 1012 and / or relay UL SCI / data from the UE 1006 to the gNB 1002 via link 1012, where the gNB 1002 may be similar to the gNBs 115A-B. The relay UE 1004 may be similar to the relay UE 125A, and the remote UEs 1006, 1034 may be similar to the remote UE 125B.

[0058] In the scheme 1000, the relay UE 1004 may communicate with the remote UE 1006 using a resource pool. In some scenarios, the relay UE 1004 may share its resource pool with the remote UE 1006. In some examples, the resource pool may be pre-configured by the gNB 1002 or the relay UE 1004 and indicated to the remote UE 1006 via the relay UE 1004.

[0059] In some scenarios (e.g., unlicensed spectrum (UL)), the relay UE 1004 may trigger a listen-before-talk process to access the wireless channel 1010 between the gNB 1002 and the relay UE 1004 and request allocation of time and frequency resources. A remote UE 1006 within communication range of the UE 1004 may request a grant of resources from the UE 1004 for transmission or reception of data to / from the UE 1004 and the gNB 1002. The UE 1004 may share some of its assigned resources from the gNB 1002 with the UE 1006. For example, the UE 1004 may request an allocation of channel occupation time (COT) from the gNB 1002, and the gNB may schedule the UE 1004 with the COT. The UE 1004 may use some of the scheduled COT and share the other part with the remote UE 1006. In the above example, the UE 1004 that initiates the COT is the COT initiator, the UE 1004 that shares the COT is the COT donor, and the UE 1006 that receives the COT is the COT recipient.

[0060] 10B illustrates an example of a sidelink communication scheme 1020 with resource sharing capability between a relay UE and one or more remote UEs in accordance with certain aspects of the disclosure. The scheme 1020 may be employed by UEs 125A-B in a network, such as the network 100, for sidelink communication. Specifically, the sidelink UEs may employ the scheme 1020 for transmission and reception of sidelink control information (SCI) and sidelink data over forward / reverse sidelink links 1012a-1012n. For example, the relay UE 1004 may transmit SCI / sidelink data to the remote UEs 1006a-1006n over a forward link, and the remote UEs 1006a-1006n may transmit SCI / sidelink data to the relay UE 1004 over a reverse link. In the scheme 1020, a relay UE 1004 within the coverage area of ​​the gNB 1002 and in communication with the gNB 1002 via link 1010 may act as a repeater for a remote UE 1006. For example, the UE 1004 may relay DL SCI / data from the gNB 1002 to the UE 1006 via links 1012a-1012n and / or relay UL SCI / data from the UE 1006 to the gNB 1002 via links 1012a-1012n. The relay UE 1004 may be similar to the relay UE 125A, and the remote UE 1006 may be similar to the remote UE 125B.

[0061] In the scheme 1020, the relay UE 1004 may communicate with the remote UE 1006 using a resource pool. In some scenarios, the relay UE 1004 may share the resource pool with the remote UEs 1006a-1006n. In some examples, the resource pool may be pre-configured by the gNB 1002 or the relay UE 1004 and indicated to the remote UE 1006 via the relay UE 1004.

[0062] In some scenarios (e.g., unlicensed spectrum (UL)), the relay UE 1004 may trigger a listen-before-talk process to access the wireless channel 1010 between the gNB 1002 and the relay UE 1004 and request allocation of time and frequency resources. One or more of the remote UEs 1006a-1006n within communication range of the UE 1004 may request a grant of resources from the UE 1004 for transmission or reception of data to / from the UE 1004 and the gNB 1002. The UE 1004 may share some of its allocated resources from the gNB 1002 with one or more of the UEs 1006a-1006n. For example, the UE 1004 may request an allocation of channel occupation time (COT) from the gNB 1002, and the gNB may schedule the UE 1004 with the COT. The UE 1004 may use a portion of the scheduled COT and share another portion with one or more of the remote UEs 1006a-1006n. In the above example, the UE 1004 that initiates the COT is the COT initiator, the UE 1004 that shares the COT is the COT donor, and the one or more of the UEs 1006a-1006n that receive the COT is the COT recipient.

[0063] FIG. 10C illustrates an example of a sidelink communication scheme 1030 having resource sharing capability between a remote UE and another remote UE, according to some aspects of the disclosure. The scheme 1030 may be employed by UEs 125A-B in a network, such as the network 100, for sidelink communication. In particular, a sidelink UE may employ the scheme 1030 for transmission and reception of sidelink control information (SCI) and sidelink data over forward / reverse sidelink links 1012, 1034. For example, a relay UE 1004 may transmit SCI / sidelink data to a remote UE 1006 over a forward link, and the remote UE 1006 may transmit SCI / sidelink data to the relay UE 1004 over a reverse link. Additionally, the remote UE 1006 may transmit or receive SCI / SL data to or from a remote UE 1032 over the link 1034.

[0064] As shown, the UE 1004 may relay DL SCI / data from the gNB 1002 to the UE 1006 via link 1012 and / or may relay UL SCI / data from the UE 1006 to the gNB 1002 via link 1012. The gNB 1002 may be similar to the gNBs 115A-B. The relay UE 1004 may be similar to the relay UE 125A and the remote UE 1006 may be similar to the remote UE 125B. Additionally, a UE 1032 within communication range of the UE 1006 may transmit or receive SCI / sidelink data to or from the UE 1006 via link 1034. In the scheme 1030, the relay UE 1004, which is within the coverage area of ​​the gNB 1002 and communicating with the gNB 1002 via link 1010, may operate as a repeater for the remote UE 1006. Additionally, a UE 1032 within communication range of the UE 1006 may transmit or receive SCI / sidelink data to or from the UE 1006 via link 1034.

[0065] In the scheme 1030, the relay UE 1004 may communicate with the remote UE 1006 using a resource pool, and the UE 1006 may communicate with the UE 1034 using another resource pool. In some scenarios, the relay UE 1004 may share its resource pool with the remote UE 1006, and the UE 1006 may share its resource pool with the UE 1032. In some examples, the resource pool may be pre-configured by the gNB 1002 or the relay UE 1004 and indicated to the remote UEs 1006 and 1032 via the relay UE 1004.

[0066] In some scenarios (e.g., unlicensed spectrum (UL)), the relay UE 1004 may trigger a listen-before-talk process to access the wireless channel 1010 between the gNB 1002 and the relay UE 1004 and request allocation of time and frequency resources. A remote UE 1006 within communication range of the UE 1004 may request a grant of resources from the relay UE 1004 for transmission or reception of data to / from the UE 1004 and the gNB 1002. The relay UE 1004 may share some of its assigned resources from the gNB 1002 with the remote UE 1006. For example, the UE 1004 may request an allocation of channel occupation time (COT) from the gNB 1002, and the gNB may schedule the UE 1004 with the COT. The UE 1004 may use some of the scheduled COT and share the other part with the remote UE 1006. Additionally, a remote UE 1032 within communication range of the remote UE 1006 may request from the remote UE 1006 a grant of resources for transmitting or receiving data to / from the UE 1006 and the gNB 1002. Thus, the remote UE 1006 may share some of its allocated resources from the UE 1004 with the remote UE 1032.

[0067] In the above example, the UE 1004 that initiates the COT is the COT initiator, the UEs 1004, 1006 that share the COT are the COT donors, and the UEs 1006, 1032 that receive the COT are the COT recipients.

[0068] FIG. 10D illustrates an example of a sidelink communication scheme 1040 with resource sharing capability between a remote UE and one or more remote UEs according to some aspects of the disclosure. The scheme 1040 may be employed by UEs 125A-B in a network, such as network 100, for sidelink communication. In particular, a sidelink UE may employ the scheme 1040 for transmission and reception of sidelink control information (SCI) and sidelink data over forward / reverse sidelink links 1012, 1034a-n. For example, the relay UE 1004 may transmit SCI / sidelink data to the remote UE 1006 over a forward link, and the remote UE 1006 may transmit SCI / sidelink data to the relay UE 1004 over a reverse link. Additionally, the remote UE 1006 may transmit or receive SCI / SL data to or from the remote UE 1032 over the links 1034a-n.

[0069] As shown, the UE 1004 may relay DL SCI / data from the gNB 1002 to the UE 1006 via link 1012 and / or may relay UL SCI / data from the UE 1006 to the gNB 1002 via link 1012. The gNB 1002 may be similar to the gNBs 115A-B. The relay UE 1004 may be similar to the relay UE 125A, and the remote UEs 1006, 1034a-n may be similar to the remote UE 125B. Additionally, the UEs 1032a-n within the communication range of the UE 1006 may transmit or receive SCI / sidelink data to or from the UE 1006 via links 1034a-n. In the scheme 1040, the relay UE 1004, which is within the coverage area of ​​the gNB 1002 and communicating with the gNB 1002 via link 1010, may operate as a repeater for the remote UE 1006. Additionally, a UE 1032 within communication range of the UE 1006 may transmit or receive SCI / sidelink data to or from the UE 1006 via link 1034.

[0070] In the scheme 1040, the relay UE 1004 may communicate with the remote UE 1006 using a resource pool, and the UE 1006 may communicate with the UEs 1034a-n using another resource pool. In some scenarios, the relay UE 1004 may share its resource pool with the remote UE 1006, and the UE 1006 may share its resource pool with the UEs 1032a-n. In some examples, the resource pool may be pre-configured by the gNB 1002 or the relay UE 1004 and indicated to the remote UEs 1006 and 1032a-n via the relay UE 1004.

[0071] In some scenarios (e.g., unlicensed spectrum (UL)), the relay UE 1004 may trigger a listen-before-talk process to access the wireless channel 1010 between the gNB 1002 and the relay UE 1004 and request allocation of time and frequency resources. A remote UE 1006 within communication range of the UE 1004 may request a grant of resources from the relay UE 1004 for transmission or reception of data to / from the UE 1004 and the gNB 1002. The relay UE 1004 may share some of its assigned resources from the gNB 1002 with the remote UE 1006. For example, the UE 1004 may request an allocation of channel occupation time (COT) from the gNB 1002, and the gNB may schedule the UE 1004 with the COT. The UE 1004 may use some of the scheduled COT and share the other part with the remote UE 1006. Additionally, one or more of the remote UEs 1032a-n that are within communication range of the remote UE 1006 may request from the remote UE 1006 a grant of resources for transmitting or receiving data to / from the UE 1006 and the gNB 1002. Thus, the remote UE 1006 may share some of its allocated resources from the UE 1004 with one or more of the remote UEs 1032a-n.

[0072] In the above example, the UE 1004 that initiates the COT is the COT initiator, the UEs 1004, 1006 that share the COT are the COT donors, and the UEs 1006, 1032a-n that receive the COT are the COT recipients.

[0073] FIG. 11 illustrates an example illustrating COT resources in the time domain according to some aspects of various exemplary embodiments of the present disclosure. The scheme 1100 may be employed by UEs 125A-B in a network such as network 100 for sidelink communication. In particular, a sidelink UE may employ the scheme 1100 for SCI / SL data communication over a sidelink forward / reverse link. In some aspects, the scheme 1100 may be employed with the schemes 1000, 1010, 1020, 1030, 1040 of FIG. 10A-D. In FIG. 1100, the x-axis represents time in some arbitrary units and the y-axis represents frequency in some arbitrary units. The sidelink COT 1100 may span a licensed spectrum or a shared radio frequency spectrum (e.g., in an unlicensed spectrum). The COT 1100 may have the same frame structure 700 as that shown in FIG. 7. For example, the COT 1100 may include a set of sidelink resource pools for a relay UE (e.g., relay UE 1004) with reference to Figures 10A-D, arranged in several slots over time and several subbands in frequency, similar to the resources 700 shown in Figure 7. The scheduled COT 1100 may include one or more slots (e.g., 110, 1120). The COT shown in Figure 11 includes two slots 1104, 1106, sidelink synchronization signals SSS 1112, 1118 (SL primary synchronization signal S-PSS and SL secondary synchronization signal S-SSS), SCI1 1108, SCI2 1120, PSSCH 1110, PSSCH 1120, and PSFCH 1124. In some examples, a COT initiator or donor may use slot 1104 and share slot 1106 with a COT recipient. A gap 1114 is provided between slots 1104 and 1106 to allow sharing of slot 1106 to COT receivers. The COT receivers may transmit a PSCCH, a PSSCH, and a PSFCH in the shared slot 1106.

[0074] In some examples, a COT initiator (e.g., UE 1004) may request allocation of a COT 1100, and a gNB (e.g., gNB 1002) may schedule the COT initiator to the COT 1100. In some aspects, the COT initiator may use 1104 and share 1106 with one or more remote UEs as described in FIGs. 10A-B. In some aspects, the COT 1100 may be shared by a COT donor or initiator to a remote UE, and the remote UE may use 1104 and share 1106 with one or more remote UEs as described in FIGs. 10C-D.

[0075] SCI1 1108, SCI2 1116 may include information needed for a remote or relay UE to decode the PSSCH. In some examples, the COT donor may transmit SCI1 1112, SCI2 116 to the COT recipient. SCI1 112, SCI2 1116 may include information needed by the COT recipient to receive the COT. For example, SCI2 may include available bandwidth, granted access, start time (slot number) of the shared portion of the COT, channel access priority value (CAP), remaining duration of the COT, etc.

[0076] In some examples, the initiator UE or donor UE may send COT sharing information to the recipient UE in SC1 1108, SCI2 1124. The COT initiator or donor UE may also send a set of destination IDs (included in SC1 1108, SCI2 1124) to the recipient UE, and the recipient UE that accepts the shared COT may send a feedback PSFCH 114, 1124 to the initiator or donor UE indicating acceptance of the COT. The recipient UE may share the COT with other UEs in the same manner.

[0077] In some examples, the initiator UE or donor UE may transmit synchronization signals 1112, 1124 (S-PSS, S-SSS) to the receiving UE. The synchronization signals 1112, 1124 are transmitted in a SL synchronization signal block (S-SSB) in the PSBCH. The synchronization signals 1112, 1124 serve as a synchronization reference for the receiving UE. Thus, the recipient UE may have the same SL timing reference and may establish communication with the donor UE.

[0078] FIG. 12 illustrates an example illustrating COT resources in the time and frequency domains according to some aspects of various exemplary embodiments of the present disclosure. The scheme 1200 may be employed by UEs 125A-B in a network such as network 100 for sidelink communication. In particular, a sidelink UE may employ the scheme 1200 for SCI / SL data communication over a sidelink forward / reverse link. In some aspects, the scheme 1200 may be employed with the schemes 1000, 1010, 1020, 1030, 1040 of FIG. 10A-D. In FIG. 1100, the x-axis represents time in some arbitrary units and the y-axis represents frequency in some arbitrary units. The sidelink COT 1200 may span a licensed spectrum or a shared radio frequency spectrum (e.g., in an unlicensed spectrum). The COT 1200 may have the same frame structure 700 as that shown in FIG. 7. For example, the COT 1100 may include a set of sidelink resource pools for a relay UE (e.g., relay UE 1004) with reference to Figures 10A-D arranged in several slots over time and several subbands in frequency, similar to the resources 700 shown in Figure 7. The scheduled COT 1200 may include one or more slots (e.g., 110, 1120). The COT shown in Figure 11 includes two slots 1204, 1208, sidelink synchronization signals SSS 1240, 1242 (SL primary synchronization signal S-PSS and SL secondary synchronization signal S-SSS), SCI1 1208, SCI2 1214, SCI3 1216, SCI4 1218, PSSCH 1220, PSSCH 1224, PSSCH 1226, PSFCH1 1228, PSFCH2 1230, and PSFCH3 1232. In some examples, a COT initiator or donor may use slot 1204 and share slot 1208 with one or more COT recipients. A gap 1212 is provided between slots 1204 and 1208 to allow sharing of slot 1206 to the COT recipients. The COT recipients may transmit a PSCCH, a PSSCH, and a PSFCH in the shared slot 1208.In some examples, the COT donor may divide the slot 1208 into several frequency subbands and share each subband to the receiving UEs. For example, the PSSCH 1220 in frequency subband 1, the PSSCH 1224 in frequency subband 2, and the PSSCH 1226 in frequency subband 3 are assigned to different recipient UEs.

[0079] In some examples, a COT initiator (e.g., UE 1004) may request allocation of a COT 1200, and a gNB (e.g., gNB 1002) may schedule the COT initiator to the COT 1200. In some aspects, the COT initiator may use 1204 and share 1208 with one or more remote UEs as described in FIGs. 10A-B. In some aspects, the COT 1200 may be shared by a COT donor or initiator to a remote UE, and the remote UE may use 1204 and share 1206 different subbands to one or more remote UEs as described in FIGs. 10C-D.

[0080] SCI1 1208, SCI2 1214, SCI3 1216, SCI4 1218 may include information required for a remote or relay UE to decode the PSSCH. In some examples, the COT donor may transmit SCI1 1208, SCI2 1214, SCI3 1216, SCI4 1218 to the COT recipient. SCI1 1208, SCI2 1214, SCI3 1216, SCI4 1218 may include information required by the COT recipient to receive the COT. For example, SCI2 1214, SCI3 1216, SCI4 1218 may include available bandwidth, granted access, start time (slot number) of the shared portion of the COT, channel access priority value (CAP), remaining duration of the COT, etc.

[0081] In some examples, the initiator UE or donor UE may send COT sharing information to the recipient UE in SC1 1208, SC2 1214, SC3 1216, SC4 1218. The COT initiator or donor UE may also send a set of destination IDs (included in SC1 1208, SC2 1214, SC3 1216, SC4 1218) to the recipient UE, and the recipient UE receiving the shared COT may send feedback PSFCH1 1228, PSFCH2 1230, PSFCH3 1232 to the initiator or donor UE indicating receipt of the COT. The recipient UE may share the COT to one or more UEs in the same manner.

[0082] In some examples, the initiator UE or donor UE may transmit synchronization signals 1240, 1242 (S-PSS, S-SSS) to the recipient UE. The synchronization signals 1212, 1218 are transmitted in a SL synchronization signal block (S-SSB) in the PSBCH. The synchronization signals 1240, 1242 serve as a synchronization reference for the recipient UE. Thus, the recipient UE may have the same SL timing reference and may establish communication with the donor UE.

[0083] FIG. 13 illustrates an example of COT sharing in a sidelink (SL) communication system with interference measurement capability to limit collisions in channel access, according to some aspects of various exemplary embodiments of the present disclosure. The scheme 1300 may be employed by UEs 125A-B in a network, such as the network 100, for sidelink communication. In particular, the sidelink UEs may employ the scheme 1300 for transmission and reception of sidelink control information (SCI) and sidelink data over forward / reverse sidelink links 1012a-n. For example, the relay UE 1304 may transmit SCI / sidelink data to the remote UEs 1306a-n over a forward link, and the remote UEs 1306a-n may transmit SCI / sidelink data to the relay UE 1304 over a reverse link. In the scheme 1300, the relay UE 1304 in the coverage area of ​​the gNB 1302 and communicating with the gNB 1302 over the link 1010 may operate as a repeater for the remote UEs 1306a-n. For example, the UE 1304 may relay DL SCI / data from the gNB 1302 to the UEs 1306a-n via link 1012 and / or may relay UL SCI / data from the UE 1306 to the gNB 1002 via link 1012, where the gNB 1002 may be similar to the gNBs 115A-B. The relay UE 1304 may be similar to the relay UE 125A, and the remote UEs 1306a-n, 1034 may be similar to the remote UE 125B.

[0084] In the scheme 1300, the relay UE 1304 may communicate with the remote UEs 1306a-n using a resource pool. In some scenarios, the relay UE 1304 may share its resource pool with the remote UEs 1306a-n. In some examples, the resource pool may be pre-configured by the gNB 1302 or the relay UE 1304 and indicated to the remote UEs 1306a-n via the relay UE 1004.

[0085] In some scenarios (e.g., unlicensed spectrum (UL)), the relay UE 1304 may trigger a listen-before-talk process to access the wireless channel 1010 between the gNB 1302 and the relay UE 1304 and request allocation of time and frequency resources. The remote UEs 1306a-n within the communication range of the UE 1304 may request the UE 1304 for resource grants for transmission or reception of data to / from the UE 1304 and the gNB 1302. The UE 1304 may share some of its allocated resources from the gNB 1302 with the UEs 1306a-n. For example, the UE 1304 may request allocation of channel occupation time (COT) from the gNB 1302, and the gNB may schedule the UE 1304 with the COT. The UE 1304 may use some of the scheduled COT and share other parts with the remote UEs 1306a-n. In the above example, the UE 1304 that initiates the COT is the COT initiator, the UE 1304 that shares the COT is the COT donor, and the UE 1306 that receives the COT is the COT recipient.

[0086] In some scenarios, the COT is shared from an initiator to several UEs, and collisions may occur between the UEs trying to access the resources. To limit collisions, the relay UE 1304 may allocate the shared COT to the UEs 1306a-n according to CAPC values, and the CPAC values ​​are configured according to traffic types to meet the Quality of Service (QoS) requirements of different traffic.

[0087] In some examples, the remote UEs 1306a-n may measure their interference levels and send reports 1320a-n to the gNB 1302 via the relay UE 1304. The gNB 1302 can then send information regarding COT sharing to the relay UE 1304 (or the initiator UE 1304), which can share the COT information among a subset of eligible recipient UEs 1306a-n that are less susceptible to collisions. As a result, the reported interference from the remote UEs may limit collisions.

[0088] FIG. 14 illustrates exemplary components of a remote or relay UE for transmission and / or reception according to some embodiments. All or a subset of the blocks and functions of FIG. 14 may be within and executed by the user equipment 1400. The antenna 1410 may be used for transmission or reception of electromagnetic signals. The antenna 1410 may comprise one or more antenna elements and may enable different input / output antenna configurations including multiple-input multiple-output (MIMO), multiple-input single-output (MISO), and single-input multiple-output (SIMO) configurations. In some embodiments, the antenna 1410 may enable massive MIMO configurations with tens of thousands of antenna elements. The antenna 1410 may enable other multi-antenna techniques such as beamforming. In some examples, depending on the capabilities of the UE 1400, the UE 1400 may only support a single antenna.

[0089] The transceiver 1420 may communicate bidirectionally over a wireless link via the antenna 1410 as described herein. For example, the transceiver 1420 may represent a wireless transceiver at the UE 1400 and may communicate bidirectionally with a wireless transceiver at a base station, or vice versa. The transceiver 1420 may include a modem for modulating packets, providing the modulated packets to the antenna 1410 for transmission, and demodulating packets received from the antenna 1410.

[0090] The memory 1430 may include RAM and ROM. The memory 1430 may store computer-readable, computer-executable code 1435 that includes instructions that, when executed, cause the processor to perform various functions described herein. In some examples, the memory 1430 may include a basic input / output system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices, among others.

[0091] The processor 1440 may include a hardware device having processing capabilities (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some examples, the processor 1440 may be configured to operate a memory using a memory controller. In other examples, the memory controller may be integrated into the processor 1440. The processor 1440 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1430) to cause the UE 1400 to perform various functions.

[0092] Central processing unit (CPU) 1450 may perform basic arithmetic, logical, control, and input / output (I / O) operations specified by computer instructions in memory 1430. User equipment 1400 may include additional peripheral components such as a graphics processing unit (GPU) 1460 and a global positioning system (GPS) 1470. GPU 1460 is dedicated circuitry for rapid manipulation and modification of memory 1430 to accelerate processing performance of user equipment 1400 and / or base station 1405. GPS 1470 may be used to enable location-based services or other services, for example, based on the geographic location of user equipment 1400.

[0093] The COT module 1470 can perform the CPT sharing process, transmission of COT information, monitoring of COT information, interference measurement and reporting, collision avoidance for COT access, and COT resource allocation over forward / reverse links, as described in Figures 10 to 13.

[0094] FIG. 15 illustrates exemplary components of a BS or gNB (e.g., gNB 1002) for transmission and / or reception according to some aspects of various exemplary embodiments of the present disclosure. All or a subset of the blocks and functions of FIG. 15 may be within the gNB 1500 and may be executed by the user equipment 1500. The antenna 1510 may be used for transmission or reception of electromagnetic signals. The antenna 1510 may comprise one or more antenna elements and may enable different input / output antenna configurations including multiple-input multiple-output (MIMO), multiple-input single-output (MISO), and single-input multiple-output (SIMO) configurations. In some embodiments, the antenna 1510 may enable massive MIMO configurations with tens of thousands of antenna elements. The antenna 1510 may enable other multi-antenna techniques such as beamforming. In some examples, depending on the capabilities of the BS gNB00, the gNB 1500 may support only a single antenna.

[0095] The transceiver 1520 may communicate bidirectionally over a wireless link via the antenna 1510 as described herein. For example, the transceiver 1520 may represent a wireless transceiver at a UE and may communicate bidirectionally with a wireless transceiver at a base station, or vice versa. The transceiver 1520 may include a modem for modulating packets, providing the modulated packets to the antenna 1510 for transmission, and demodulating packets received from the antenna 1510.

[0096] The memory 1530 may include RAM and ROM. The memory 1530 may store computer-readable, computer-executable code 1535 including instructions that, when executed, cause the processor to perform various functions described herein. In some examples, the memory 1530 may comprise a basic input / output system (BIOS) that may control basic hardware or software operations such as interaction with peripheral components or devices, among other things.

[0097] The processor 1540 may comprise a hardware device having processing capabilities (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some examples, the processor 1540 may be configured to operate a memory using a memory controller. In other examples, the memory controller may be integrated into the processor 1540. The processor 1540 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1530) to cause the gNB 1700 to perform various functions.

[0098] A central processing unit (CPU) 1550 may perform basic arithmetic, logical, control, and input / output (I / O) operations specified by computer instructions in memory 1530 .

[0099] The COT module agent 1580 may perform COT resource allocation and management, interference management for remote UEs and relay UEs, collision avoidance for COT access, and data communication for remote UE links, as described in Figures 10 to 13.

[0100] 16 is a flow diagram illustrating a COT sharing method performed by a relay UE (e.g., UE 2004) according to some aspects of various exemplary embodiments of the present disclosure. The steps of the method 1600 may be performed by a computing device (e.g., a processor, processing circuit, and / or other components) of the UE. As illustrated, the method 1600 may include additional steps before, after, and between the recited steps.

[0101] In step 1602, the relay UE triggers a listen-before-talk (LBT) process to request access to a first resource for transmitting data to or receiving data from a gNB. The first resource may include a COT, and the relay UE is the COT initiator.

[0102] In step 1604, the relay UE receives a first grant indicating a first resource for transmitting data to or receiving data from the gNB, the first resource including a time and frequency subband allocated in the COT for the relay UE.

[0103] In step 1606, the relay UE receives a request from one or more remote UEs in the first set to access second resources for transmitting or receiving data to / from one or more UEs in the first set. The one or more remote UEs may use the second resources for transmitting or receiving data to the gNB via the relay UE. The second resources may include a remaining COT time duration or available COT frequency subbands not used by the relay UE.

[0104] In step 1608, the relay UE sends a grant of the second resource to one or more remote UEs of the first set, the second resource including the remaining portion of the first resource not used by the first UE. The relay UE may share the remaining duration of the COT and the available frequency subbands to the one or more remote UEs. In some examples, the relay UE may consider interference measurement reports from the one or more UEs to determine how to share the remaining duration of the COT and the available frequency subbands to the one or more remote UEs. In some other examples, the relay UE may share the remaining duration and the available frequency subbands based on the CPAC value. In some examples, the relay UE may send the COT information in the SCI. The COT information may include information required to decode the PSCCH, including, but not limited to, bandwidth, grant access, start time (slot number), channel access priority value (CAP), remaining duration of the COT, etc.

[0105] FIG. 17 illustrates a flow diagram illustrating a COT sharing method performed by a remote UE in accordance with some aspects of various exemplary embodiments of the present disclosure.

[0106] In step 1702, the remote UE sends a request to the relay UE to access a first resource for transmitting data to the relay UE or receiving data from a second UE, the first resource being a portion of a second resource granted to the relay UE by a base station (BS) and not used by the relay UE. The first resource may include a COT duration and a frequency subband allocated by the gNB in ​​response to an LBT trigger to the relay UE. The relay UE may use a portion of the COT and share the remaining portion with one or more remote UEs.

[0107] In step 1704, in response to the request, the remote UE receives a grant of the second resource. In some examples, the remote UE may use a portion of the second resource and share the unused portion with one or more UEs. In some examples, the remote UE may receive COT information in the SCI. The COT information may include information needed to decode the PSCCH, including, but not limited to, bandwidth, granted access, start time (slot number), channel access priority value (CAP), remaining duration of the COT, etc.

[0108] In step 1706, the remote UE transmits data or control information to the relay UE or receives data or control information from the relay UE.

[0109] The functions described in this disclosure may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Instructions or code may be stored or transmitted on a computer-readable medium for implementation of the functions. Other examples for implementation of the functions disclosed herein are also within the scope of this disclosure. Implementation of the functions may be through physically co-located or distributed elements (e.g., in various locations), including being distributed such that portions of the functions are implemented in different physical locations.

[0110] Computer-readable media includes, but is not limited to, non-transitory computer storage media. Non-transitory storage media can be accessed by general-purpose or special-purpose computers. Examples of non-transitory storage media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, and the like. Non-transitory media can be used to carry or store desired program code means (e.g., instructions and / or data structures) and can be accessed by general-purpose or special-purpose computers, or general-purpose or special-purpose processors. In some examples, the software / program code can be transmitted from a remote source (e.g., a website, a server, etc.) using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. In such examples, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are within the definition of media. Combinations of the above examples are also included within the scope of computer-readable media.

[0111] As used in this disclosure, the use of the term "or" in a list of items indicates an inclusive list. The list of items may be preceded by phrases such as "at least one of" or "one or more of." For example, a list of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A and B and C). Also, as used in this disclosure, entering a list of conditions with the phrase "based on" should not be interpreted as "based only on" the set of conditions, but rather as "based at least in part on" the set of conditions. For example, a result described as "based on condition A" may be based on both condition A and condition B without departing from the scope of this disclosure.

[0112] In this specification, the terms "comprise", "include", or "contain" may be used interchangeably, have the same meaning, and should be construed as inclusive and non-limiting. The terms "comprise", "include", or "contain" may be used before a list of elements to indicate that at least all of the recited elements in the list are present, but other elements not in the list may also be present. For example, if A contains B and C, then both {B, C} and {B, C, D} are within the scope of A.

[0113] The present disclosure describes exemplary configurations in connection with the accompanying drawings, which do not represent all examples that may be implemented or all configurations within the scope of the present disclosure. The term "exemplary" should not be interpreted as "preferred" or "advantageous compared to other examples", but rather as "illustration, instance, or example". By reading the present disclosure, including the description of the embodiments and drawings, it will be understood by those skilled in the art that the technology disclosed herein may be implemented using alternative embodiments. Those skilled in the art will understand that the embodiments, or certain features of the embodiments described herein, may be combined to arrive at yet other embodiments for practicing the technology described in the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. 1. A method of wireless communication, comprising: triggering a Listen-Before-Talk (LBT) process by a first user equipment (UE) requesting access to a first resource for transmitting data to or receiving data from a base station (BS); receiving, by the first UE in response to triggering the LBT, a first grant indicating the first resource for transmitting data to or receiving data from the base station (BS); requesting, by the first UE, from one or more UEs of a first set of UEs within communication range of the first UE, access to a second resource for transmission of data between the first UE and the one or more UEs of the first set; sending, by the first UE, a grant of the second resources to one or more UEs of the first set, the second resources including a remaining portion of the first resources not used by the first UE; A method comprising:

2. requesting, at a third user equipment (UE) of the first set of UEs, from one or more UEs of a second set of UEs that are within communication range of the third UE, access to a third resource for transmission of data between the third UE and one or more UEs of the second set; sending a grant of the third resources to one or more UEs of the second set, the third resources including a remaining portion of the second resources not used by the third UEs; The method of claim 1 further comprising:

3. 2. The method of claim 1, wherein the first grant is transmitted in a first Sidelink Control Information (SCI) message.

4. The method of claim 1 , wherein the first resource includes a frequency bandwidth and a duration.

5. 5. The method of claim 4, wherein a grant from the first user equipment (UE) to one or more UEs of the second set is transmitted in a second sidelink control information (SCI2) message.

6. The SCI2 is bandwidth available to one or more user equipments (UEs) of the first set; a timestamp for transmission of data between one or more UEs of the first set and the first UE; a channel access priority value (CAP) for traffic of one or more UEs in the first set; a remaining duration not used by the first UE; and The method of claim 4 , comprising:

7. 2. The method of claim 1, wherein one or more user equipments (UEs) of the first set that receive the grant to access the second resource transmit control signals on a physical sidelink control channel (PSCCH), synchronization signals on a physical sidelink synchronization channel (PSSCH), and feedback signals on a physical sidelink feedback channel (PSFCH) to the first UE.

8. 2. The method of claim 1, further comprising receiving from the base station (BS) at the first user equipment (UE) a Network Assistant Information (NAI) including information needed to access the second resource granted by the first UE to one or more UEs of the first set, and an identification of the UE of the first set that receives the grant of the second resource.

9. 2. The method of claim 1, wherein the first user equipment (UE) allocates the second resource to one or more UEs of the first set based on a channel access priority class (CAPC) value of the one or more UEs allocated traffic.

10. measuring interference by one or more user equipments (UEs) of the first set; reporting the measured interference to the first UE; The method of claim 1 further comprising:

11. The method of claim 10 , wherein the first user equipment (UE) allocates the second resource to one or more UEs based on a reported interference measurement.

12. 2. The method of claim 1, wherein the first user equipment (UE) divides the second resource into several subsets and transmits each subset to one or more UEs of the first set that have requested to access the resource.

13. 1. A method of wireless communication, comprising: sending a request by a first user equipment (UE) to a second UE to access a first resource for transmitting data to or receiving data from the second UE, the first resource being a part of a second resource granted to the second UE by a base station (BS) and not used by the second UE; receiving, by the first UE, a grant of the second resource in response to the request; transmitting, by the first UE, data or control information to the second UE or receiving data or control information from the second UE; A method comprising:

14. 14. The method of claim 13, wherein the second resource comprises a channel occupation time (COT) time and frequency resource assigned to the second user equipment (UE).

15. 14. The method of claim 13, wherein the first user equipment (UE) transmits control signals on a physical sidelink control channel (PSCCH), transmits synchronization signals on a physical sidelink synchronization channel (PSSCH), and transmits feedback signals on a physical sidelink feedback channel.

16. 14. The method of claim 13, wherein receiving the grant comprises receiving a message in a sidelink control channel (SCI) information.

17. measuring interference by the first user equipment (UE); reporting the measured interference to the second UE; The method of claim 13 further comprising:

18. The sidelink control channel (SCI), a frequency bandwidth available to the first user equipment (UE); and a timestamp for transmission of data between the first UE and the second UE; a remaining duration of the second resource not used by the first UE; and 17. The method of claim 16, comprising:

19. The method of claim 17 , wherein the first resource is determined by a measurement of the reported interference.

20. A user equipment (UE) comprising a transceiver, the transceiver comprising: configured to trigger a Listen-Before-Talk (LBT) process to request access to a first resource for transmitting data to or receiving data from a Base Station (BS); The transceiver includes: receiving, by the UE in response to the LBT, a first grant indicating the first resource for transmitting data to or receiving data from the base station (BS); requesting, by the UE, from one or more other UEs of a first set of other UEs within communication range of the first UE, access to second resources for transmission of data between the first UE and the one or more other UEs of the first set; transmitting, by the UE, a grant of the second resources to one or more other UEs of the first set, the second resources including a remaining portion of the first resources not used by the first UE; A user equipment (UE) configured to:

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