Facilitating sidelink mode 2 random selection for supporting sidelink drx

Abstract

The present disclosure relates to facilitating sidelink mode-2 random selection for supporting sidelink DRX. A method for communication is provided, including receiving, with a first user equipment, an allocation of one or more physical sidelink control channel resources from a network node, where the first user equipment is configured to perform sidelink discontinuous reception. The method further includes performing autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool. The method further includes performing sidelink communication utilizing at least one of: a resource of the one or more allocated physical sidelink control channel resources, or one of the one or more selected resources of the physical sidelink shared channel.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 065,548 filed August 14, 2020, the contents of which are incorporated herein in their entirety. BACKGROUND TECHNICAL FIELD

[0004] Example and non-limiting embodiments relate generally to sidelink communications, and more specifically to sidelink resource selection.

[0005] Brief description of prior developments

[0006] It is known that for a user equipment configured to perform sidelink communications, sidelink resource allocation is performed in mode 1 or mode 2. BRIEF DESCRIPTION OF DRAWINGS

[0007] The foregoing aspects and other features are explained in the following description, taken in connection with the accompanying drawings, wherein:

[0008] Figure 1 is a block diagram of a possible and non-limiting exemplary system in which exemplary embodiments can be practiced;

[0009] Figure 2 is a diagram illustrating features as described herein;

[0010] Figure 3 is a diagram illustrating features as described herein;

[0011] Figure 4 is a diagram illustrating features as described herein;

[0012] Figure 5 is a flow diagram illustrating steps as described herein; and

[0013] Figure 6 is a flow diagram illustrating steps as described herein. DETAILED DESCRIPTION

[0014] The following abbreviations can be found in the specification and / or drawings:

[0015] 3GPP Third Generation Partnership Project

[0016] 5G Fifth Generation

[0017] 5GC 5G Core Network

[0018] AMF Access and Mobility Management Function

[0019] BS Base Station

[0020] CG Configured Grant

[0021] CP Control Plane

[0022] CSI Channel State Information

[0023] CU Central Unit

[0024] DL Downlink

[0025] DRX Discontinuous Reception

[0026] DU Distributed Unit

[0027] eNB (or eNodeB) Evolved Node B (e.g. LTE base station)

[0028] EN-DC E-UTRA-NR Dual Connectivity

[0029] en-gNB or En-gNB A node that provides NR user plane and control plane protocol terminations towards UEs and acts as a secondary node in EN-DC

[0030] E-UTRA Evolved Universal Terrestrial Radio Access, i.e. LTE radio access technology

[0031] gNB (or gNodeB) Base station for 5G / NR, i.e. a node that provides NR user plane and control plane protocol terminations towards UEs and is connected to 5GC via NG interfaces

[0032] HARQ Hybrid Automatic Repeat reQuest

[0033] I / F Interface

[0034] L1 Layer 1

[0035] LTE Long Term Evolution

[0036] MAC Medium Access Control

[0037] MCS Modulation and Coding Scheme

[0038] MME Mobility Management Entity

[0039] ng or NG New Generation

[0040] ng-eNB or NG-eNB New Generation eNB

[0041] NR New Radio

[0042] N / W or NW Network

[0043] PDCP Packet Data Convergence Protocol

[0044] PHY Physical layer

[0045] PSCCH Physical SL Control Channel

[0046] PSSCH Physical SL Shared Channel

[0047] RAN Radio Access Network

[0048] RF Radio Frequency

[0049] RLC Radio Link Control

[0050] RS Reference Signal

[0051] RRH Remote Radio Head

[0052] RRC Radio Resource Control

[0053] RU Radio Unit

[0054] Rx Receiver

[0055] SCI Sidelink Control Information

[0056] SDAP Service Data Adaptation Protocol

[0057] SGW Serving Gateway

[0058] SIB System Information Block

[0059] SL Sidelink

[0060] SL-RSRP Sidelink Reference Signal Received Power

[0061] SMF Session Management Function

[0062] SPS Semi-Persistent Scheduling

[0063] TB Transport Block

[0064] TTI Transmission Time Interval

[0065] Tx Transmitter

[0066] UE User Equipment (e.g., wireless device, typically a mobile device)

[0067] UL Uplink

[0068] UP User Plane

[0069] UPF User Plane Function

[0070] Uu Interface between BS and UE

[0071] V2X Vehicle-to-Everything wireless communication technology

[0072] VRU Vulnerable Road Users

[0073] Go to Figure 1 This figure illustrates a block diagram of one possible and non-limiting example that can be practiced. User equipment (UE) 110, radio access network (RAN) node 170, and network elements(s) 190 are illustrated. Figure 1 In the example, User Equipment (UE) 110 wirelessly communicates with Wireless Network 100. The UE is a wireless device that can access Wireless Network 100. UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected via one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 may be address, data, or control buses and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics, or other optical communication devices. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. UE 110 includes a module 140, which includes one or both of portions 140-1 and / or 140-2, which can be implemented in various ways. Module 140 may be implemented in hardware as module 140-1, such as being implemented as part of one or more processors 120. Module 140-1 may also be implemented as an integrated circuit or via other hardware, such as a programmable gate array. In another example, module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and executed by one or more processors 120. For example, one or more memories 125 and computer program code 123 may be configured to use one or more processors 120 to cause user equipment 110 to perform one or more operations as described herein. UE 110 communicates with RAN node 170 via radio link 111.

[0074] Despite Figure 1 Not illustrated, but UE 110 can also be used via short-range communication technologies (such as...) ) Communicate with other UEs. If wireless communication with the network is unavailable or impossible, or if communication is not possible in addition to network communication, then UE110 may be able to communicate with other UEs via sidelink.

[0075] The RAN node 170 in this example is a base station that provides access to wireless network 100 for wireless devices, such as UEs 110. The RAN node 170 can be, for example, a base station for 5G, also known as New Radio (NR). In 5G, the RAN node 170 can be an NG-RAN node, which is defined to be a gNB or ng-eNB. A gNB is a node that terminates the NR user plane and control plane protocol terminations towards a UE and connects via an NG interface to a 5GC, such as, for example, network element(s) 190. An ng-eNB is a node that terminates the E-UTRA user plane and control plane protocol terminations towards a UE and connects via an NG interface to a 5GC. NG-RAN nodes can include multiple gNBs, which can also include a central unit (CU) (gNB-CU) 196 and distributed unit(s) (DU) (gNB-DU), of which a DU 195 is shown. It should be noted that a DU can include or be coupled to and control a radio unit (RU). The gNB-CU is a logical node hosting the RRC, SDAP, and PDCP protocols of a gNB or the RRC and PDCP protocols of an en-gNB that host the operation of one or more gNB-DUs. The gNB-CU terminates the Fl interface with the gNB-DU. The Fl interface is illustrated as a label 198, but the label 198 also illustrates a link between a remote element of the RAN node 170 and a centralized element of the RAN node 170, such as the link between the gNB-CU 196 and the gNB-DU 195. The gNB-DU is a logical node hosting the RLC, MAC, and PHY layers of a gNB or en-gNB and whose operation is controlled in part by the gNB-CU. One gNB-CU supports one or more cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface 198 with the gNB-CU. It should be noted that the DU 195 is considered to include the transceiver 160, for example, as part of a RU, but some examples of the DU can have a transceiver 160 as part of a separate RU, for example, under the control of and connected to the DU 195. The RAN node 170 can also be an eNB (enhanced NodeB) base station for (Long Term Evolution), or any other suitable base station or node.

[0076] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces ((N / W I / F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx 162, and a transmitter, Tx 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 can include the processor(s) 152, the memory 155, and the network interface 161. It should be noted that the DU 195 can also contain its own memory and processor(s) and / or other hardware, but these elements are not shown.

[0077] The RAN node 170 includes a module 150, which includes one or both of parts 150-1 and / or 150-2, which can be implemented in a variety of ways. The module 150 can be implemented in hardware as module 150-1, such as being implemented as part of the processor(s) 152. The module 150-1 can also be implemented as an integrated circuit or through other hardware, such as a programmable gate array. In another example, the module 150 can be implemented as module 150-2, which is implemented as computer program code 153 and executed by the processor(s) 152. For example, the memory(ies) 155 and the computer program code 153 are configured to, using the processor(s) 152, cause the RAN node 170 to perform one or more operations as described herein. It should be noted that the functionality of the module 150 can be distributed, such as being distributed between the DU 195 and the CU 196, or implemented solely in the DU 195.

[0078] The one or more network interfaces 161 communicate through networks, such as communicating via links 176 and 131. Two or more gNBs 170 can communicate using, for example, link 176. The link 176 can be wired or wireless or both, and can implement, for example, the Xn interface for 5G, the X2 interface for LTE, or other suitable interfaces for other standards.

[0079] The one or more buses 157 can be address, data, or control buses, and can include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 can be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for gNB implementations for 5G, where other elements of the RAN node 170 can be at a physically different site from the RRH / DU, and the one or more buses 157 can be implemented in part as, e.g., fiber optic cables or other suitable network connections to connect the other elements of the RAN node 170 (e.g., central unit (CU), gNB-CU) to the RRH / DU 195. The designation 198 also indicates those network link(s).

[0080] It should be noted that the description herein indicates that a "cell" performs functions, but it should be clear that the device forming the cell will perform the functions. A cell constitutes a part of a base station. That is, there can be multiple cells per base station. For example, there can be three cells per single carrier frequency and associated bandwidth, each covering one third of a 360 degree region, such that the coverage area of a single base station covers an approximately elliptical or circular shape. Further, each cell can correspond to a single carrier, and a base station can use multiple carriers. Thus, if there are three 120 degree cells per carrier and two carriers, then a base station has a total of 6 cells.

[0081] Wireless network 100 can include one or more network elements 190, which can comprise core network functionality, and provide connectivity to another network, such as a telephone network and / or a data communications network (e.g., the Internet), via one or more links 181. Such core network functionality for 5G can include Access and Mobility Management Function(s) (AMF(s)) and / or User Plane Function(s) (UPF(s)) and / or Session Management Function(s) (SMF(s)). Such core network functionality for LTE can include MME (Mobility Management Entity) / SGW (Serving Gateway) functionality. These are merely exemplary functionality that can be supported by network element(s) 190, and it should be noted that both 5G and LTE functionality can be supported. RAN node 170 is coupled via link 131 to network elements 190. Link 131 can be implemented, for example, as an NG interface for 5G or an SI interface for LTE or other suitable interface for other standards. Network elements 190 include one or more processors 175, one or more memories 171, and one or more network interfaces (N / W I / F(s)) 180 interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause network elements 190 to perform one or more operations.

[0082] Wireless network 100 can implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based, managed entity, a virtual network. Network virtualization involves platform virtualization, often in conjunction with resource virtualization. Network virtualization is classified as either external, combining many networks or parts of networks into a virtual unit, or internal, providing network-like functionality for software containers on a single system. It should be noted that virtualized entities resulting from network virtualization are still implemented to some extent using hardware, such as processors 152 or 175 and memories 155 and 171, and that such virtualized entities also produce technical effects.

[0083] The computer-readable memories 125, 155, and 171 can be of any type suitable to the local technical environment and can be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. The computer-readable memories 125, 155, and 171 can be means for performing the storage functions described herein. The processors 120, 152, and 175 can be of any type suitable to the local technical environment, and can include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), and processors based on multi-core processor architectures, as non-limiting examples. The processors 120, 152, and 175 can be means for performing the functions described herein, such as controlling the UE 110, the RAN node 170, and other functions as described herein.

[0084] In general, the various embodiments of the user equipment 110 can include, but are not limited to, smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras with wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances with wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, tablets with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions. In addition, the various embodiments of the user equipment 110 can include, without limitation, devices integrated into vehicles, infrastructure associated with vehicle travel, wearable devices used by pedestrians or other non-vehicle users of the roadways, user equipment that is not associated with business users, and user equipment configured to participate in sidelink scenarios, such as public safety user equipment and / or other commercial user equipment.

[0085] Features as described herein generally relate to, but are not limited to, New Radio (NR) Sidelink (SL) enhancements in 3GPP Release 17 and / or later. For example, NR SL methods can be implemented to provide communication between vehicles and the network, infrastructure(s), other vehicle(s), or other road user(s) in the surrounding / adjacent area. Such communication can implement Proximity Services (ProSe), or the transmission of information about the surrounding environment between very close devices, such as Device-to-Device (D2D) communication techniques. Such direct communication can be available even when network coverage is not available. Additionally or alternatively, NR SL methods can be implemented in scenarios that are not related to traffic users, such as public safety scenarios and / or commercial scenarios. Enhancements to sidelink procedures can be configured to provide power saving in these Vehicle-to- Wireless Communication Technology (V2X) and other use cases. It should be noted that enhancements configured to provide power saving in sidelink procedures can not be limited to unicast procedures; one of ordinary skill in the art will appreciate that the present disclosure can also relate to sidelink groupcast, multicast, and / or broadcast procedures.

[0086] In the present disclosure, there can be disclosed example embodiments configured to enable SL UE power saving when communicating using SL techniques.

[0087] In 3GPP Release 16, NR V2X has been developed to support advanced V2X services. In 3GPP Release 17, NR SL can be enhanced to support a wider range of use cases, such as public safety, entertainment, and other commercial applications. In these and other applications, power saving can be considered a key requirement. For example, in 3GPP Release 17, a work item (WI) on NR Sidelink Enhancements [3GPP RP-193231] states:

[0088] “Power saving enables UEs with battery constraints to perform sidelink operations in an energy-efficient manner. Rel-16 NR Sidelink was designed with the assumption of “always-on” operation by the UE when operating sidelink, e.g., only focusing on UEs installed in vehicles with sufficient battery capacity. Vulnerable road users (VRUs) in V2X use cases, as well as UEs in public safety and commercial use cases, need solutions for power saving in Rel-17 where the power consumption of the UE needs to be minimized.”

[0089] Accordingly, sidelink enhancements can be implemented to provide power saving in SL UEs. This document [3GPP RP-193231] also provides the following related objectives:

[0090] “......2. Resource allocation enhancements:

[0091] - specify resource allocation to reduce power consumption of the UE

[0092] - Baseline is to introduce the principles of Rel-14 LTE sidelink random resource selection and partial sensing to Rel-16 NR sidelink resource allocation mode 2.

[0093] - It should be noted that baselining on Rel-14 does not preclude introducing new solutions to reduce power consumption in cases where the baseline does not work properly.

[0094] - Study the feasibility and benefits of enhancement(s) in mode 2 for enhanced reliability and reduced latency, taking into account both PRR and PIR as defined in TR 37.885 (RAN#89), and specify identified solutions if deemed feasible and beneficial

[0095] - Determine a set of resources at UE-A. This set is transmitted to UE-B in mode 2 and UE-B takes this into account when selecting resources for its own transmission

[0096] 3. Sidelink DRX for broadcast, groupcast and unicast

[0097] - Define on-duration and idle duration for sidelink and specify corresponding UE procedures

[0098] - Specify mechanisms aiming at aligning sidelink DRX wake-up times among UEs communicating with each other

[0099] - Specify mechanisms aiming at aligning sidelink DRX wake-up times with Uu DRX wake-up times in UEs in coverage

[0100] The combination of resource allocation enhancements targeting reliability and reduced latency for SL UE operation and the implementation of discontinuous reception (DRX) in SL UEs to provide power saving can cause practical issues. For example, when SL DRX is implemented and a SL UE operates in mode 2 SL resource allocation, the SL UE can not listen to or receive sidelink transmission(s), including sidelink control information (SCI) over physical sidelink control channel (PSCCH) during the idle period of the SL DRX cycle. This situation will impact sensing in mode 2 resource allocation and thus the performance of SL communication using mode 2 resource allocation.

[0101] NR SL was specified in 3GPP Release 16 to support V2X services. As in the LTE SL design, there are two resource allocation modes. In SL resource allocation mode 1, the network / network node / base station (e.g., NG-RAN) schedules SL transmission resource(s) for SL UE(s). In SL resource allocation mode 2, the SL UE autonomously selects SL transmission resources from a resource pool. In mode 2, the UE performs a sensing procedure to receive resource reservation information of other nearby UEs from their transmission SCI. Thereafter, the UE can select resource(s) for transmission based on the result of the sensing procedure. SL resource allocation mode 2 can also be referred to as “sensing-based mode 2 resource allocation”.

[0102] In NR SL, SL control information (SCI) indicates the resources and other transmission parameters for transmission of a transport block (TB) of SL data and other control information (such as CSI reporting) by a SL Tx UE. SCI consists of two parts. In the first stage SCI transmitted / received on PSCCH, resource allocation and modulation and coding scheme (MCS) related information is carried. This information is also used for sensing in mode 2 resource allocation. In the second stage SCI transmitted / received on PSSCH, hybrid automatic repeat request (HARQ) and SL L2 ID related information is carried.

[0103] In NR SL, sensing-based mode 2 resource allocation relies on continuous monitoring and reception of at least first stage SCI sent over PSCCH. The sensing history within a sensing window (e.g., 100 ms or 1100 ms as specified in TS 38.331) is used for resource selection at a single UE in mode 2. However, when SL DRX is implemented for a SL UE in mode 2, the SL UE can not listen to or receive SL transmission(s) occurring during an idle period of SL DRX, such as first stage SCI transmitted over PSCCH during an idle period of a SL DRX cycle. Thus, when the UE wakes up from an idle period of a DRX cycle, the sensing history can not be available to the SL UE at least at the start of the next on period of the SL UE’s DRX cycle. Because SL resource allocation mode 2 relies on information received from transmitted SCI of neighboring / nearby SL UEs in order to perform SL transmission resource selection, sensing-based mode 2 resource allocation can not be available starting at the next SL DRX on period. In other words, the SL UE can not be able to perform transmission of SL control plane (CP) and / or user plane (UP) data over SL using SL resources selected by sensing-based mode 2 resource allocation starting at the next SL DRX on period.

[0104] Reference is now made to Figure 2, illustrates an example scenario in which a SL UE is configured with SL DRX and attempts to operate in SL resource allocation mode 2. At 210, the SL UE is in a DRX ON period and can perform sidelink reception and transmission. At 220, the SL UE is in a DRX OFF period and at least discontinuously monitors PSCCH. Thus, the SL UE does not receive first stage SCI of nearby SL UEs during the DRX OFF period 220. At 230, the SL UE is in a DRX ON period and can be interested in performing SL transmission. But because the SL UE did not receive first stage SCI of nearby SL UEs at 220 (i.e., did not perform sensing), the SL UE can not be able to autonomously select unoccupied SL transmission resources from the resource pool at least at the beginning of the DRX ON period at 230, because the SL UE does not have information about any resources reserved by other nearby SL UEs.

[0105] Due to the lack of sensing history of the SL UE because of the lack of monitoring of first stage SCI on PSCCH transmitted from nearby SL UEs, random selection for mode 2 resource allocation can be more suitable for SL UEs configured with DRX than resource allocation based on the outcome of sensing the resource pool. SL mode 2 random selection is specified in LTE and NR SL. However, the collision resolution mechanism for random selection is not supported. In the current random selection design, both PSCCH and PSSCH resources can be randomly selected by a SL UE. If the selected resources of two or more SL UEs collide with each other, the first stage SCI transmitted over PSCCH can not be correctly received by any SL UE(s). Thus, for collision resolution, the collision on PSSCH resources (e.g., second stage SCI and / or SL data) can not be detectable. The poor performance of random selection due to collision propensity and lack of specified collision resolution procedure is well recognized and can be particularly problematic in high UE density scenarios that many SL applicable use cases can have.

[0106] Instead of using SL resource allocation mode 2, a SL UE configured with SL DRX can be configured to use SL resource allocation mode 1. By using SL resource allocation mode 1, a SL UE configured with SL DRX can be able to avoid the sensing procedure and thus avoid the issues as described above. Figure 2The scenario illustrated in the middle. However, SL resource allocation mode 1 is only applicable to SL UEs in a radio resource control (RRC) connected state. Thus, additional power can be consumed to maintain the SL UEs in the RRC connected state. From a power saving perspective, it can be desirable to keep the SL UEs in an RRC idle or inactive state if there is no active UL / DL transmission over the Uu interface for the SL UEs. Since SL DRX is designed to yield power saving effects, it can be unreasonable to configure the SL UEs with SL DRX to use only SL resource allocation mode 1.

[0107] In example embodiments, procedure(s) for collision detection and resolution for SL mode 2 random selection for SL UEs configured with DRX can be specified. In example embodiments, SL UEs configured with DRX can be enabled to be allocated with dedicated PSCCH resources as in SL mode 1, while allowing the use of random selection to select PSSCH resources from the SL mode 2 resource pool. Alternatively, PSSCH resources can be autonomously selected from the SL mode 2 resource pool using partial sensing based selection or full sensing based selection. In other words, selection of PSSCH resources can be performed using less than full sensing history or based on no sensing history. Such selection can use random selection methods known to those of ordinary skill in the art or some other selection scheme known to those of ordinary skill in the art.

[0108] In example embodiments, a semi-persistent scheduling (SPS) and / or configured grant (CG) type of dedicated PSCCH resource from a mode 1 resource pool can be allocated by a base station (BS) to a SL UE (UE1) configured with DRX. This resource allocation can be valid in a configured validity area regardless of the RRC state (RRC connected, inactive, or idle state) of UE1. This case can mean that the allocated PSCCH resource remains valid within the validity area even when UE1 enters the RRC inactive or idle state instead of staying in the RRC connected state. Optionally, the allocated SPS / CG type of dedicated PSCCH resource from the mode 1 resource pool can be configured to be valid within each SL DRX on period of UE1 until sensing results are available within the on period. For example, UE1 can use the allocated PSCCH resource from the mode 1 resource pool to transmit a sidelink transmission (i.e., first stage SCI) during the DRX_ON period of UE1 until UE1 has sufficient sensing results to enable UE1 to autonomously select resources based on the sensing results. This case can occur during a later portion of the DRX_ON period of UE1.

[0109] It should be noted that in the above example and subsequent examples, “UE1” can be used to indicate a SL UE configured with SL DRX. The use of UE1 should not be considered limiting the scope of the present disclosure. For example, multiple SL UEs can be configured with SL DRX.

[0110] In an example embodiment, the PSSCH resource can be randomly selected by UE1 from the mode 2 resource pool, while the associated first stage SCI carrying information of the selected PSSCH resource is transmitted via a dedicated PSCCH resource allocated to the UE by the network. While UE1 randomly selects the PSSCH resource from the mode 2 resource pool, the allocated PSCCH resource(s) can be considered so that the constraints on PSCCH and PSSCH resources can be satisfied at least in the time domain. In other words, UE1 can perform random selection of PSSCH resource from the mode 2 resource pool, but the random selection can be limited by the allocation of PSCCH resource from the mode 1 resource pool.

[0111] Alternatively, the PSSCH resource can be selected using partial sensing based resource selection or full sensing based resource selection. In this specification, the use of the term “random selection” or the like should not be considered to limit the example embodiment to a resource selection method based on no sensing history; a resource selection method based on some or full sensing can be considered to be within the scope of the present disclosure.

[0112] In an example embodiment, UE1 can detect conflicts between its (randomly) selected PSSCH resources and those of another SL UE (e.g., UE2) based on its monitoring of Phase 1 SCIs sent from other neighboring or nearby SL UEs (e.g., UE2 and / or UE3) via conflict-free PSSCH resources. In an example embodiment, UE1 can detect conflicts in its (randomly) selected PSSCH resources by identifying overlapping PSSCH resources used by (multiple) other SL UEs (UE2) or by receiving conflict indications from (multiple) other SL UEs (UE3) in the form of their own UE ID (i.e., UE1's ID) and / or information about the same resources randomly selected by themselves. UE1 can identify overlaps between used PSSCH resources by reading SCIs received from (multiple) other neighboring or nearby SL UEs (e.g., UE2). For example, if UE2 indicates in its SCI the resources it is using, and UE1 has (randomly) selected one or more of the same resources for use, then UE1 can identify an overlap. When receiving a conflict indication from, for example, UE3, UE3 may have detected an overlap between the resources used by UE1 and UE2, and may have sent a conflict indication, including one or more UE IDs (e.g., the IDs of UE1 and / or UE2), to a neighboring or nearby SL UE. Additionally or alternatively, the conflict indication from, for example, UE3 may include information related to the resources in which it has detected a conflict. If the resource information overlaps with one or more (randomly) selected PSSCH resources of UE1, then UE1 can detect the conflict based on the conflict indication.

[0113] It should be noted that UE2 and UE3 can be SL UEs configured with DRX, SL UEs without DRX, or a combination of SL UEs with or without DRX.

[0114] Now for reference Figure 3 The illustration shows the behavior of an SL UE configured according to an example embodiment. In the example, there may be other SL UEs configured with DRX that are adjacent to other SL UEs. These other SL UEs may or may not be configured with DRX. Figure 3 In the examples described above, such as one or more of the example embodiments, the SL DRX UE can be configured by the serving network using Mode 2 with a Mode 1 resource allocation configured for the PSCCH and associated PSSCH resources, randomly selected by the serving network along with other SL-related configurations. The serving network can configure the example SL DRX UE using broadcast signaling (e.g., in the SIB) or dedicated signaling (e.g., dedicated RRC messages). Those skilled in the art will understand from the example embodiments of this disclosure which methods the serving network can use to configure the SL UE.

[0115] Reference is now made to Figure 3 At 310, the SL DRX UE can determine that it is configured to support using mode 1 resource allocation for PSCCH and / or simultaneously randomly selecting PSSCH resources from a mode 2 resource pool for sidelink transmissions, as described in one or more of the example embodiments above. While in this example the SL DRX UE is configured to perform random selection of PSSCH resources, in other examples the SL DRX UE can be configured to perform other types of selection of PSSCH resources, which can include selecting PSSCH resources based on partial or full sensing history. While the SL DRX UE is configured with SL DRX (i.e., the SL UE is DRX enabled), the SL UE can be triggered to enter RRC connected state in order to obtain / receive dedicated PSCCH resource allocation from the serving network at 312. This allocation of PSCCH resources can be valid regardless of the RRC state of the SL DRX UE. After receiving the PSCCH allocation from the NW, the SL DRX UE can enter RRC idle or inactive state.

[0116] In example embodiments, using a regular procedure, the SL DRX UE can report SL traffic characteristic(s) to the network using SL UE information and / or UE assistance information as specified for NR SL in order to facilitate the serving NW to allocate suitable PSCCH resources in SPS / CG manner. For example, the allocated PSCCH resources can be able to meet requirements (e.g., traffic periodicity, latency requirements, etc.) according to the traffic characteristics of the (reported) SL traffic, at least in the time domain.

[0117] In example embodiments, by possibly allocating non-overlapping PSCCH resources to multiple SL UEs, at least in the time domain, the serving NW can facilitate avoiding collision of randomly selected PSSCH resources at 314 and facilitate collision detection among the multiple SL UEs (at 320, 330, and / or 340). In Figure 3 In an example, the serving NW can allocate non-overlapping PSCCH resources to the SL DRX UE and one or more neighboring / nearby SL UEs.

[0118] In an example embodiment, the dedicated PSCCH resource can be signaled to the SL DRX UE using RRC signaling, which can be similar to CG Type 1 RRC signaling. In an alternative example embodiment, using a simplified or reduced procedure for optimization purpose, a SL UE with configured DRX operation while in RRC idle / inactive state can be configured to indicate a new cause and / or a configured SL DRX profile in a RRC connection request sent to the serving BS in order to request dedicated mode 1 PSCCH resource. The new cause can be configured to indicate to the NW that the RRC connection request can have been triggered in order to request dedicated PSCCH resource allocation for a UE configured with SL DRX. The NW can use the configured SL DRX profile (related to DRX cycle, i.e. active or idle period length) to configure dedicated mode 1 SPS / CG type of PSCCH resource such that the SPS / CG type of PSCCH resource can be configured to be valid at the beginning of each SL DRX active period until sensing result is available in that active period. Thus, when the SL UE wakes up and enters a SL DRX active period, it will start sensing and the SPS / CG type of PSCCH resource can be configured to be valid until the time period of the configured sensing window has elapsed, provided that the active period is longer than the sensing window. After the sensing is conducted for sufficient time in the SL DRX active period to collect sensing history information, the SL DRX UE can automatically select SL transmission resource based on the result of sensing according to sensing based SL resource allocation mode 2. Alternatively, the selection of SL transmission resource can be based on less sensing history than the sensing history specified in sensing based SL resource allocation mode 2, i.e. partial sensing history.

[0119] Reference is now made to Figure 3 After the SL UE obtains / receives the allocated mode 1 PSCCH resource at 312, the SL UE can go back to RRC idle or inactive state. The allocated mode 1 PSCCH resource can be valid within a configured valid area, which can cover multiple neighboring cells. Since the amount of required resource(s) for PSCCH transmission of the first stage SCI is much smaller than the amount of resource(s) required for PSSCH transmission of actual SL CP or UP data, it can be possible to have dedicated PSCCH resource within an area larger than one cell without causing resource usage inefficiency.

[0120] At 314, the SL DRX UE can randomly select a PSSCH resource from the Mode-2 resource pool. This random selection can occur when the SL DRX UE wakes up during an active period of its DRX cycle. This random selection can take into account the PSCCH resource allocated from the Mode-1 resource pool at 312. This consideration of the allocated PSCCH resource can be used to prevent resource(s) collision. For example, if there is a constraint on the time offset between a PSCCH and an associated PSSCH transmission, then the randomly selected PSSCH resource can be randomly selected based on the allocated PSCCH resource in at least the time domain to comply with such constraint. In another example, if there are more allocated PSCCH resources than actually needed for the transmission of buffered SL CP and / or UP data to be transmitted by the SL DRX UE, then the SL DRX UE can randomly select a PSSCH resource in order to make it possible to associate multiple PSCCH resources with one PSSCH resource. In this way, multiple first-stage SCI can be transmitted through the selected PSCCH resource associated with one PSSCH transmission to improve the reliability of the SCI transmission. In another example embodiment, the random selection can be based on at least some sensing performed by the SL DRX UE, i.e., a partial sensing history.

[0121] At 316, the SL DRX UE can detect a PSCCH resource collision. The SL DRX UE can detect a PSCCH resource collision based on, for example, SCI received from other proximate / nearby SL UEs.

[0122] At 330, the SL DRX UE can detect a resource collision if SCI received from other / proximate / nearby UE(s) shows / indicates one or more PSSCH resources that at least partially overlap with the PSSCH resource randomly selected at 314. Alternatively, the SL DRX UE can detect a resource collision if the SL DRX UE receives from other / proximate / nearby SL UE(s) SCI indicating a detection of a collision and including the SL DRX UE’s SL UE ID or including the conflicting resource(s) that at least partially overlap with the PSSCH resource randomly selected at 314.

[0123] At 320, the proximate / nearby SL UE can detect a PSSCH collision based on SCI received from at least two UEs. These SCI can be transmitted in the same transmission timer interval (TTI) or SCI transmission. Alternatively, the proximate / nearby SL UE can receive colliding PSSCH transmissions in the same TTI using at least partially overlapping PSSCH resources. At 322, the proximate / nearby SL UE can determine which UE’s ID should be included in the collision indication. The decision can take into account SL UE traffic priority associated with one or more SL UEs involved in the detected collision, SL UE capability associated with one or more SL UEs involved in the detected collision, etc. At 324, the proximate / nearby SL UE can transmit the collision indication. The collision indication can be transmitted as part of SCI and can be received at 340 by the SL DRX UE.

[0124] At 318, based on the SL DRX UE’s detection of PSSCH resource collision, the SL DRX UE can reselect PSSCH resources. The reselection can include random selection, selection based on partial sensing, selection based on full sensing, or some other type of PSSCH resource selection.

[0125] Reference is now made to Figure 4 , which illustrates a simplified or reduced procedure for PSCCH resource allocation for SL UEs configured with DRX, as for example at 312 of Figure 3 . In Figure 4 , illustrated at the UE, in this example the UE is a sidelink UE configured with discontinuous reception; BS1; and already BS2. At 1, BS1 can configure SL DRX operation for the UE in mode 2. The configuration can include configuring the UE to perform resource selection from a given mode 2 resource pool randomly. Alternatively, the configuration can include configuring the UE to perform resource selection from a given mode 2 pool or resources using partial sensing based selection or full sensing based selection. The configuration can also include configuring the UE for allocation of dedicated PSCCH resources from a mode 1 resource pool according to SL resource allocation mode 1.

[0126] At 2, the UE can be in RRC idle mode or RRC inactive mode and needs to perform sidelink communication while performing sidelink discontinuous reception. Based on the UE’s configuration, the UE can need to be allocated PSCCH resources by the network. Therefore, at 3, the UE can transmit an RRC connection request to BS1. The RRC connection request can include a cause, such as a PSCCH resource allocation request.

[0127] At 4, BS1 can determine mode 1 PSCCH resources to allocate for the UE. In example embodiments, the allocation can be based on or influenced by PSCCH allocations that BS1 has made to other SL UEs. In example embodiments, the allocation can be based on or influenced by information related to SL traffic characteristics. At 5a, BS1 can indicate to BS2 the mode 1 PSCCH resources that BS1 has determined to allocate to the UE. This coordination with BS2 can be used to ensure that the allocated mode 1 PSCCH resources for a SL UE with DRX can be used throughout the active area served by more than one BS. By coordinating the mode 1 PSCCH resource allocation as shown in step 5a, BS1 can ensure that BS2 is aware that a particular PSCCH resource will be used by the UE and thus avoid actions (e.g. resource allocation) that can cause resource conflicts.

[0128] At 5, BS1 can send an RRC connection release message to the UE. The RRC connection release message can include the allocation of mode 1 resources determined at 4. At 6, the UE can be in RRC idle or RRC inactive mode. The UE can be configured to use the allocated mode 1 PSCCH resources for sidelink communications while performing SL DRX.

[0129] For PSSCH resource conflict detection, as in Figure 3 At 316 of FIG. 3, the SL UE can determine or identify that other proximate / nearby SL UE(s) have reserved / selected resources that at least partially overlap with its own randomly selected PSSCH resource(s). In example embodiments, a SL UE (UE1) configured with DRX can determine that its randomly selected resource(s) collide with resources of a nearby SL UE (UE2) by reading the SCI of UE2. It should be noted that due to half-duplex SL operation, such collision detection can only be feasible among SL UEs transmitting SCI with different transmission time intervals (TTIs); thus, in the present example embodiment, UE1 and UE2 can transmit SCI with different TTIs, such that the SCI of UE2 can be received by UE1.

[0130] It should be noted that while three UEs, UE1, UE2, and UE3, can be discussed in the preceding and following examples, example embodiments are not limited to interactions among three SL UEs; more or fewer SL UEs can be involved in PSSCH resource collision, PSSCH resource collision detection, and / or PSSCH resource collision resolution in accordance with example embodiments of the present disclosure. Further, while UE1 is a DRX-configured SL UE that is experiencing a resource collision with UE2 in these examples, in other examples, other UE or UEs can be configured with DRX and / or can be determined to be associated with a resource collision with a DRX-configured SL UE. These examples are presented to simply explain example embodiments of the present disclosure, and not to limit the scope of the present disclosure.

[0131] In another example embodiment, if another proximate SL UE (e.g., UE3) identifies or determines that at least partially overlapping resources have been selected by two or more SL UEs (e.g., UE1 and UE2) by reading their SCI, then a PSSCH resource collision can be detected. UE3 can indicate the resource collision in its own SCI transmission(s), e.g., as a resource collision indication included in the SCI. The resource collision indication can be in the form of overlapping resource block indices or conflicting UE IDs. For example, for the detected resource collision between UE1 and UE2, UE3’s resource collision indication can include resource block indices associated with one or more of the resource(s) determined to overlap between UE1 and UE2, and / or can include one or more UE IDs associated with the SL UEs for which the resource collision has been detected. In this example, UE1 and / or UE2’s UE IDs can be included in the resource collision indication. In example embodiments, UE3 can not indicate IDs for all conflicting UEs, but only for selected conflicting UE(s). The SL UE that is not involved in the resource collision but has detected the resource collision (UE3 in this example) can determine to indicate one or more UE IDs based on, e.g., priority information indicated in the respective SCI of the conflicting UEs (UE1 and UE2 in this example). For example, if the priority received from UE2 is lower than the priority received from UE1, UE3 can indicate UE2’s ID as the ID of the conflicting UE in the resource collision indication.

[0132] In example embodiments, because UE2’s ID is indicated in UE3’s collision indication, UE2 can be triggered upon receiving the collision indication from UE3 to detect the collision (based on UE3’s received SCI) and / or to perform a PSSCH resource reselection procedure.

[0133] In example embodiments, if a SL UE detects that its own resources collide with those of another SL UE, the SL UE can be triggered to reselect PSSCH resources based on its own priority information it can provide in its own SCI and the priority information of the one or more SL UEs whose resources collide with its own, which can be provided in the SCI(s) of the one or more SL UEs.

[0134] In an example, in case of a collision between UE1 and UE2, UE2 can receive an indication of the collision from UE3. Although UE2 can not have identified the resource collision itself before receiving the collision indication from UE3, UE2 can stop transmitting SCI over PSCCH in order to detect the collision itself. This can enable UE2 to obtain more detailed information about the resource collision with the other colliding UE (UE1 in this example) (e.g. priority information, colliding resource blocks, etc.). Additionally, since the UE indicating the collision (UE3 here) and the indicated colliding UE (UE2 here) can not be co-located, this action by UE2 can also allow UE2 to check or determine whether the PSCCH transmission of the colliding UE1 reaches UE2 at a high sidelink reference signal received power (SL-RSRP) level. Based on the SL-RSRP level, UE2 can determine whether to trigger PSSCH resource reselection.

[0135] If the PSSCH resource(s) are selected from a mode 2 resource pool common to both random and sensing based resource selection, a collision SL UE applying random selection can be triggered to reselect PSSCH resources in case the other colliding UE(s) use sensing based resource allocation. For example, if UE1 is configured to perform random selection and UE2 is configured to perform sensing based resource allocation, upon detecting a resource collision between UE1 and UE2, UE1 can be triggered to reselect PSSCH resources. As disclosed in one or more example embodiments of the present disclosure, the detection of whether the other SL UE(s) are using random or sensing based resource selection can be based on whether the associated PSCCH resources are allocated from a mode 1 resource pool or a mode 2 resource pool. In other words, based on the resource pool the PSCCH resource(s) used by the SL UE belong to, the PSSCH resource selection method used by the SL UE can be determined. Alternatively or additionally, the PSSCH resource selection method used by the SL UE can be determined based on an indication received in the SCI transmitted by the SL UE. For example, a 1-bit indication can be included in the SCI indicating whether the SL UE is using random or sensing based resource selection.

[0136] The technical effect of example embodiments of the present disclosure can be to introduce collision-free resource allocation for PSCCH transmissions and use of PSCCH transmissions on the collision-free resource(s) to enable collision detection and avoidance for randomly selected PSSCH resources.

[0137] Figure 5 Potential steps of an example method 500 are illustrated. The example method 500 can include receiving, with a first user equipment, an allocation of one or more physical sidelink control channel resources from a network node, where the first user equipment is configured to perform sidelink discontinuous reception, 510; performing an autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool, 520; and performing a sidelink communication utilizing at least one of: resources of the one or more allocated physical sidelink control channel resources or resources of the one or more selected resources of the physical sidelink shared channel, 530. The autonomous selection of the one or more resources of the physical sidelink shared channel from the resource pool can include performing a random selection. Random selection methods within a set are known to those of ordinary skill in the art. Additionally or alternatively, the autonomous selection can be based on available sensing history, which can be partial sensing history or complete sensing history.

[0138] Figure 6 Potential steps of an example method 600 are illustrated. The example method 600 can include sending a configuration to a sidelink user equipment, the configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation, receive a physical sidelink control channel resource allocation, and perform an autonomous selection of a physical sidelink shared channel resource from a resource pool, 610; receiving a request for a physical sidelink control channel resource allocation from the sidelink user equipment, 620; and transmitting the physical sidelink control channel resource allocation to the sidelink user equipment in response to the request, 630. The autonomous selection that the configuration enables the sidelink user equipment to perform can be, for example, a random selection. Additionally or alternatively, the autonomous selection can be based on sensing history available or accumulated by the sidelink user equipment, which can be partial sensing history or complete sensing history.

[0139] According to one aspect, an example method can be provided that includes receiving, with a first user equipment, an allocation of one or more physical sidelink control channel resources from a network node, where the first user equipment can be configured to perform sidelink discontinuous reception; performing an autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool; and performing a sidelink communication utilizing at least one of: resources of the one or more allocated physical sidelink control channel resources or resources of the one or more selected resources of the physical sidelink shared channel.

[0140] The example method can further include performing a sensing procedure during an active period of the first user equipment.

[0141] The performing of the sidelink communication can include performing the sidelink transmission utilizing at least one of: resources of the one or more allocated physical sidelink control channel resources or resources of the one or more selected resources of the physical sidelink shared channel.

[0142] The performing of the sensing procedure can include receiving sidelink control information from one or more other user equipments.

[0143] The performing of the autonomously selecting of the one or more resources of the physical sidelink shared channel from the resource pool can include selecting the one or more resources from the resource pool using at least one of: a random selection, a partial sensing based selection, or a full sensing based selection.

[0144] The received sidelink control information can include first stage sidelink control information received utilizing at least one of the one or more allocated physical sidelink control channel resources of the first user equipment.

[0145] The example method can further include detecting a resource conflict between at least one selected resource of the one or more selected resources of the physical sidelink shared channel of the first user equipment and at least one physical sidelink shared channel resource selected by a second user equipment based at least in part on receiving a sidelink transmission using resources of the one or more allocated physical sidelink control channel resources.

[0146] The detecting of the resource conflict can include at least one of: receiving sidelink control information from the second user equipment, the sidelink control information can include an indication of the at least one selected physical sidelink shared channel resource of the second user equipment; and determining that the at least one selected physical sidelink shared channel resource of the second user equipment overlaps with the at least one selected resource of the first user equipment; or receiving a sidelink transmission from a third user equipment, the sidelink transmission can include a collision indication, wherein the collision indication can include at least one of an identifier of the first user equipment or an indication of the at least one selected resource of the first user equipment.

[0147] The received sidelink transmission from the third user equipment can include at least one of: sidelink control information or a medium access control control element.

[0148] The example method can further include reselecting at least one resource of the physical sidelink shared channel from the resource pool based on the detected resource conflict.

[0149] The reselecting can be based at least in part on at least one of a priority of the first user equipment or a priority of the second user equipment.

[0150] The example method can also include stopping, in response to detecting the resource conflict, transmission by the first user equipment with the one or more allocated physical sidelink control channel resources; and performing sensing for additional sidelink control information from the second user equipment, where the reselecting can be based at least in part on the additional sidelink control information.

[0151] The first user equipment can not perform a sensing procedure in performing the autonomous selection of the one or more resources from the pool of physical sidelink shared channel resources.

[0152] Receiving the allocation of the one or more physical sidelink control channel resources can include receiving the sidelink resource allocation from a network node using the first user equipment.

[0153] The resource pool can include a pool of resources autonomously selected by the first user equipment.

[0154] Receiving the allocation of the one or more physical sidelink control channel resources can include receiving an allocation of a dedicated physical sidelink control channel resource of a semi-persistent scheduling type or a configured grant type.

[0155] The received allocation of the one or more physical sidelink control channel resources can be configured to be valid while the first user equipment is in any of: a radio resource control connected state, a radio resource control idle state, or a radio resource control inactive state.

[0156] The received allocation of the one or more physical sidelink control channel resources can be configured to be valid at least within a configured valid area that includes a network node.

[0157] Performing the autonomous selection of the one or more resources of the physical sidelink shared channel from the resource pool can be based at least in part on the one or more allocated physical sidelink control channel resources.

[0158] Performing the autonomous selection of the one or more resources of the physical sidelink shared channel from the resource pool can correspond in a time domain to at least one of the one or more allocated physical sidelink control channel resources.

[0159] The first user equipment can be configured to support receiving the allocation of the one or more physical sidelink control channel resources and performing the autonomous selection of the one or more resources of the physical sidelink shared channel from the resource pool based on at least one of: broadcast signaling or dedicated signaling received from a network node.

[0160] Receiving the allocation of one or more physical sidelink control channel resources can comprise transmitting at least one message to the network node using the first user equipment, the message comprising at least one of: a sidelink traffic characteristic, a sidelink DRX configuration related information, or a request for physical sidelink control channel resource allocation; and in response, receiving the allocation of one or more physical sidelink control channel resources when the first user equipment is in a radio resource control connected state.

[0161] Transmitting the at least one message to the network node can comprise transmitting at least one radio resource control connection setup procedure message to the network node, and receiving the allocation in response can comprise receiving at least one radio resource control connection setup procedure message from the network node.

[0162] Performing the autonomous selection of one or more resources can be based at least in part on a number of the one or more allocated physical sidelink control channel resources.

[0163] According to one example embodiment, an apparatus can comprise at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: receive an allocation of one or more physical sidelink control channel resources from a network node, wherein the apparatus can be configured to perform sidelink discontinuous reception; perform an autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool; and perform a sidelink communication using at least one of: one of the one or more allocated physical sidelink control channel resources or one of the one or more selected resources of the physical sidelink shared channel.

[0164] Performing the sidelink communication can comprise the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: perform the sidelink transmission using at least one of: one of the one or more allocated physical sidelink control channel resources or one of the one or more selected resources of the physical sidelink shared channel.

[0165] Performing the autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool can comprise the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: select the one or more resources from the resource pool using at least one of: a random selection, a partial sensing based selection, or a full sensing based selection.

[0166] The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to: detect a resource conflict between at least one selected resource of the one or more selected resources of the physical sidelink shared channel of the apparatus and at least one physical sidelink shared channel resource selected by the second user equipment based at least in part on receiving the sidelink transmission using the one or more allocated physical sidelink control channel resources.

[0167] Detecting the resource conflict can include the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: receive, from the second user equipment, sidelink control information including an indication of at least one selected physical sidelink shared channel resource of the second user equipment; and determine that the at least one selected physical sidelink shared channel resource of the second user equipment overlaps with the at least one selected resource of the apparatus; or receive, from the third user equipment, a sidelink transmission including a collision indication, where the collision indication can include at least one of an identifier of the apparatus or an indication of the at least one selected resource of the apparatus.

[0168] The sidelink transmission received from the third user equipment can include at least one of: sidelink control information or a medium access control control element.

[0169] The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to: reselect at least one resource of the physical sidelink shared channel from the resource pool based on the detected resource conflict.

[0170] The reselecting can be based at least in part on at least one of a priority of the apparatus or a priority of the second user equipment.

[0171] The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to: stop transmitting with the one or more allocated physical sidelink control channel resources in response to detecting the resource conflict; and perform sensing for additional sidelink control information from the second user equipment, where the reselecting can be based at least in part on the additional sidelink control information.

[0172] Receiving the allocation of the one or more physical sidelink control channel resources can include the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: receive, from a network node, a sidelink resource allocation.

[0173] The resource pool can include a resource pool autonomously selected by the apparatus.

[0174] Receiving an allocation of one or more physical sidelink control channel resources can include the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to receive an allocation of: a dedicated physical sidelink control channel resource of a semi-persistent scheduling type or a dedicated physical sidelink control channel resource of a configured grant type.

[0175] The received allocation of one or more physical sidelink control channel resources can be configured to be valid at least when the apparatus is in any one of: a radio resource control connected state, a radio resource control idle state, or a radio resource control inactive state.

[0176] The received allocation of one or more physical sidelink control channel resources can be configured to be valid at least within a configured validity area comprising the network node.

[0177] Performing the autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool can be based at least in part on the one or more allocated physical sidelink control channel resources.

[0178] Performing the autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool can correspond in the time domain to at least one of the one or more allocated physical sidelink control channel resources.

[0179] An example apparatus can be configured to support receiving an allocation of one or more physical sidelink control channel resources and performing the autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool based on at least one of: broadcast signaling or dedicated signaling received from a network node.

[0180] Receiving an allocation of one or more physical sidelink control channel resources can include the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to send at least one message to the network node, the message comprising at least one of: sidelink traffic characteristics, sidelink DRX configuration related information, or a request for physical sidelink control channel resource allocation; and in response, receive the allocation of one or more physical sidelink control channel resources while in a radio resource control connected state.

[0181] Sending at least one message to the network node can include the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to send at least one radio resource control connection establishment procedure message to the network node, and receiving the allocation can include the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to receive at least one radio resource control connection establishment procedure message from the network node. The performing the autonomous selection of one or more resources can be based at least in part on a number of the one or more allocated physical sidelink control channel resources.

[0182] According to one example embodiment, an apparatus can comprise: circuitry configured to perform receiving, using a first user equipment, an allocation of one or more physical sidelink control channel resources from a network node, wherein the first user equipment is configured to perform sidelink discontinuous reception; circuitry configured to perform autonomously selecting one or more resources of a physical sidelink shared channel from a resource pool; and circuitry configured to perform sidelink communication using at least one of: resources of the one or more allocated physical sidelink control channel resources or resources of the one or more selected resources of the physical sidelink shared channel.

[0183] As used in this application, the term "circuitry" can refer to one or more or all of the following: (a) hardware-only circuitry such as only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as (as applicable): (i) combinations of analog and / or digital hardware circuit(s) with software / firmware and (ii) portions of hardware processor(s) with software (including digital signal processors); software, including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions and (c) hardware circuit(s), such as a microprocessor(s) or a portion of a microprocessor, that requires software (e.g., firmware) for operation, but software that may

[0184] According to one example embodiment, an apparatus can comprise means for performing: receiving, from a network node, an allocation of one or more physical sidelink control channel resources, wherein the apparatus can be configured to perform sidelink discontinuous reception; performing autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool; and performing sidelink communication using at least one of: resources of the one or more allocated physical sidelink control channel resources or resources of the one or more selected resources of the physical sidelink shared channel.

[0185] According to one example embodiment, a non-transitory computer-readable medium including program instructions stored thereon that, when executed using at least one processor, cause the at least one processor to perform operations of: receiving, using a first user equipment, an allocation of one or more physical sidelink control channel resources from a network node, wherein the first user equipment can be configured to: perform a sidelink discontinuous reception; perform an autonomous selection of one or more resources of a physical sidelink shared channel from a resource pool; and perform a sidelink communication using at least one of: one of the one or more allocated physical sidelink control channel resources or one of the one or more selected resources of the physical sidelink shared channel.

[0186] According to one aspect, an example method can be provided, comprising: transmitting, to a sidelink user equipment, a configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation, receive a physical sidelink control channel resource allocation, and perform an autonomous selection of physical sidelink shared channel resources from a resource pool; receiving, from the sidelink user equipment, a request for the physical sidelink control channel resource allocation; and in response to the request, transmitting, to the sidelink user equipment, the physical sidelink control channel resource allocation.

[0187] According to one example embodiment, an apparatus can comprise: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform operations of: transmitting, to a sidelink user equipment, a configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation, receive a physical sidelink control channel resource allocation, and perform an autonomous selection of physical sidelink shared channel resources from a resource pool; receiving, from the sidelink user equipment, a request for the physical sidelink control channel resource allocation; and in response to the request, transmitting, to the sidelink user equipment, the physical sidelink control channel resource allocation.

[0188] According to one example embodiment, an apparatus can comprise: circuitry configured to perform transmitting, to a sidelink user equipment, a configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation, receive a physical sidelink control channel resource allocation, and perform an autonomous selection of physical sidelink shared channel resources from a resource pool; circuitry configured to perform receiving, from the sidelink user equipment, a request for the physical sidelink control channel resource allocation; and circuitry configured to perform, in response to the request, transmitting, to the sidelink user equipment, the physical sidelink control channel resource allocation.

[0189] According to one example embodiment, an apparatus can include means for transmitting a configuration to a sidelink user equipment, the configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation, receive a physical sidelink control channel resource allocation, and perform autonomous selection of physical sidelink shared channel resources from a resource pool; receiving a request from the sidelink user equipment for the physical sidelink control channel resource allocation; and transmitting the physical sidelink control channel resource allocation to the sidelink user equipment in response to the request.

[0190] According to one example embodiment, a non-transitory computer-readable medium comprising program instructions stored thereon that, when executed using at least one processor, cause the at least one processor to: transmit a configuration to a sidelink user equipment, the configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation, receive a physical sidelink control channel resource allocation, and perform autonomous selection of physical sidelink shared channel resources from a resource pool; receive a request from the sidelink user equipment for the physical sidelink control channel resource allocation; and transmit the physical sidelink control channel resource allocation to the sidelink user equipment in response to the request.

[0191] It should be understood that the foregoing description is only illustrative. Various alternative and modified versions can be devised according to different implementations. For example, the features recited in the various dependent claims can be combined with each other in any appropriate combinations; additionally, features from different embodiments described above can be selectively combined into new embodiments. Accordingly, the description is meant to be taken only by way of example and the scope of the claims that follow should be given their broadest reasonable interpretation.

Claims

1. A method for communication comprising: receiving, with a first user equipment, an allocation of one or more physical sidelink control channel resources from a mode 1 resource pool from a network node, wherein the one or more physical sidelink control channel resources are configured to be valid during an on-duration of a sidelink discontinuous reception until a sensing result of the on-duration is available, wherein the first user equipment is configured to perform the sidelink discontinuous reception; performing a random selection of one or more resources of a physical sidelink shared channel from a mode 2 resource pool, wherein the random selection is restricted to the allocation of physical sidelink shared channel resources from the mode 1 resource pool; performing a sidelink communication with a resource of the one or more randomly selected resources of the physical sidelink shared channel in response to the sensing result of the on-duration being available; and detecting a resource conflict between at least one of the one or more selected resources of the physical sidelink shared channel of the first user equipment and at least one physical sidelink shared channel resource selected by a second user equipment based at least in part on receiving a sidelink transmission with the resource of the one or more allocated physical sidelink control channel resources; wherein detecting the resource conflict comprises receiving a sidelink control information from the second user equipment including an indication of at least one selected physical sidelink shared channel resource of the second user equipment and determining that at least one selected physical sidelink shared channel resource of the second user equipment overlaps with at least one selected resource of the first user equipment, and wherein the random selection of the physical sidelink shared channel resources is performed based on a partial sensing history or a full sensing history.

2. The method of claim 1, further comprising: reselecting at least one resource of the physical sidelink shared channel from the mode 1 resource pool based on the detected resource conflict based at least in part on at least one of a priority of the first user equipment or a priority of the second user equipment or based at least in part on additional sidelink control information.

3. The method of claim 1, wherein detecting the resource conflict comprises: receiving a sidelink transmission including a conflict indication from a third user equipment, wherein the conflict indication includes at least one of an identifier of the first user equipment or an indication of at least one selected resource of the first user equipment.

4. The method of claim 3, wherein the sidelink transmission received from the third user equipment includes at least one of: sidelink control information, or a medium access restriction control element.

5. The method of any one of claims 1-4, wherein receiving the allocation of the one or more physical sidelink control channel resources comprises: receiving an allocation of the following from the network node: dedicated physical sidelink control channel resources of a semi-persistent scheduling type, or dedicated physical sidelink control channel resources of a configured grant type. ​ 6. The method of any one of claims 1-4, wherein the received allocation of the one or more physical sidelink control channel resources is further configured to be valid while the first user equipment is in a radio resource control connected state.

7. The method of any one of claims 1-4, wherein the received allocation of the one or more physical sidelink control channel resources is configured to be valid at least within a configured validity area that includes the network node.

8. The method of any one of claims 1-4, wherein receiving the allocation of the one or more physical sidelink control channel resources comprises: sending at least one message to the network node, the at least one message including at least one of: a sidelink traffic characteristic, a sidelink DRX configuration related information, or a request for physical sidelink control channel resource allocation; and in response, receiving the allocation of the one or more physical sidelink control channel resources while in a radio resource control connected state.

9. The method of claim 8, wherein sending the at least one message to the network node comprises: sending at least one radio resource control connected setup procedure message to the network node; and wherein receiving the allocation comprises: receiving at least one radio resource control connected setup procedure message from the network node.

10. An apparatus for communication, comprising: at least one processor; and at least one non-transitory memory and computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: receive, from a network node, an allocation of one or more physical sidelink control channel resources from a mode 1 resource pool, wherein the one or more physical sidelink control channel resources are configured to be valid during an on-duration period of a sidelink discontinuous reception until a sensing result of the on-duration period is available, wherein the apparatus is configured to perform the sidelink discontinuous reception; perform a random selection of one or more resources of a physical sidelink shared channel from a mode 2 resource pool, wherein the random selection is restricted to the allocation of physical sidelink shared channel resources from the mode 1 resource pool; in response to the sensing result of the on-duration period being available, perform a sidelink communication utilizing a resource of the one or more randomly selected resources of the physical sidelink shared channel; and detect a resource conflict between at least one of the one or more selected resources of the physical sidelink shared channel of the apparatus and at least one physical sidelink shared channel resource selected by a second user equipment based at least in part on receiving a sidelink transmission utilizing the resource of the one or more allocated physical sidelink control channel resources. wherein detecting the resource conflict comprises receiving a sidelink control information from the second user equipment, the sidelink control information comprising an indication of at least one selected physical sidelink shared channel resource of the second user equipment, and determining that the at least one selected physical sidelink shared channel resource of the second user equipment overlaps with the at least one selected resource of the apparatus, and wherein the random selection of the physical sidelink shared channel resource is performed based on a partial sensing history or a full sensing history.

11. The apparatus of claim 10, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to: reselect at least one resource of the physical sidelink shared channel from the mode- 1 resource pool based on the detected resource conflict based at least in part on at least one of a priority of the apparatus or a priority of the second user equipment or based at least in part on additional sidelink control information.

12. The apparatus of claim 10, wherein detecting the resource conflict comprises the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least one of: receive a sidelink transmission comprising a conflict indication from a third user equipment, wherein the conflict indication comprises at least one of an identifier of the apparatus or an indication of at least one selected resource of the apparatus.

13. The apparatus of claim 12, wherein the sidelink transmission received from the third user equipment comprises at least one of: a sidelink control information, or a medium access restriction control element.

14. The apparatus of any one of claims 10 to 13, wherein receiving the allocation of the one or more physical sidelink control channel resources comprises the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to: receive an allocation of the following from the network node: a dedicated physical sidelink control channel resource of a semi-persistent scheduling type, or a dedicated physical sidelink control channel resource of a configured grant type.

15. The apparatus of any one of claims 10 to 13, wherein the received allocation of the one or more physical sidelink control channel resources is further configured to be valid while the apparatus is in a radio resource control connected state.

16. The apparatus of any one of claims 10 to 13, wherein the received allocation of the one or more physical sidelink control channel resources is configured to be valid at least within a configured valid area comprising the network node.

17. The apparatus of any one of claims 10 to 13, wherein receiving the allocation of the one or more physical sidelink control channel resources comprises the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to: send at least one message to the network node, the at least one message comprising at least one of: an indication of the at least one selected resource of the apparatus, or an indication of the at least one selected physical sidelink shared channel resource of the apparatus. sidelink traffic characteristics, sidelink DRX configuration related information, or a request for physical sidelink control channel resource allocation; and in response, receiving the allocation of the one or more physical sidelink control channel resources while in a radio resource control connected state.

18. The apparatus of claim 17, wherein the sending of the at least one message to the network node includes the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to send at least one radio resource control connection setup procedure message to the network node, and wherein the receiving of the allocation includes the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to receive at least one radio resource control connection setup procedure message from the network node.

19. A method for communication, comprising: sending, by a network node, a configuration to a sidelink user equipment, the configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation; receiving, at the network node, a request for physical sidelink control channel resource allocation from the sidelink user equipment; and sending, by the network node, a physical sidelink control channel resource allocation from a mode 1 resource pool to the sidelink user equipment in response to the request, wherein the physical sidelink control channel resource allocation includes one or more physical sidelink control channel resources that are confirmed as valid during an on-duration period of a sidelink discontinuous reception operation until sensing results of the on-duration period are available, wherein a resource of the one or more physical sidelink control channel resources of the allocation is configured to be used to perform a sidelink communication before a resource is randomly selected from a mode 2 resource pool of one or more resources of a physical sidelink shared channel in response to the sensing results of the on-duration period being available, wherein the random selection is restricted to the allocation of physical sidelink shared channel resources from the mode 1 resource pool; the physical sidellink control channel resource allocation sends a dedicated physical sidelink control channel resource of a semi-persistent scheduling type and a dedicated physical sidelink control channel resource of a configured grant type; receiving at least one message from the sidelink user equipment, the at least one message including sidelink traffic characteristics and sidelink discontinuous reception configuration related information.

20. The method of claim 19, wherein the physical sidelink control channel resource allocation is further configured to be valid while the sidelink user equipment is in a radio resource control connected state.

21. The method of claim 19, wherein the physical sidelink control channel resource allocation is configured to be valid at least within a configured valid area that includes the network node.

22. The method of claim 19, wherein the sending of the physical sidelink control channel resource allocation includes: receiving at least one message from the sidelink user equipment, the at least one message including at least one of: sidelink traffic characteristics, sidelink DRX configuration related information, or a request for physical sidelink control channel resource allocation; and in response, transmitting the allocation of the one or more physical sidelink control channel resources while in a radio resource control connected state.

23. An apparatus for communication, comprising: at least one processor; and at least one non-transitory memory and computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: transmit, to a sidelink user equipment, a configuration configured to enable the sidelink user equipment to perform a sidelink discontinuous reception operation; receive, from the sidelink user equipment, a request for physical sidelink control channel resource allocation; and in response to the request, transmit, to the sidelink user equipment, the physical sidelink control channel resource allocation from a mode 1 resource pool, wherein the physical sidelink control channel resource allocation comprises one or more physical sidelink control channel resources confirmed as valid during an on-duration period of a sidelink discontinuous reception operation until sensing results of the on-duration period are available, wherein prior to a random selection of a resource from a mode 2 resource pool of one or more resources of a physical sidelink shared channel in response to the sensing results of the on-duration period being available, a resource of the allocated one or more physical sidelink control channel resources is configured for performing a sidelink communication, wherein the random selection is restricted to the allocation of physical sidelink shared channel resources from the mode 1 resource pool; transmit the physical sidelink control channel resource allocation of a dedicated physical sidelink control channel resource of a semi-persistent scheduling type and a dedicated physical sidelink control channel resource of a configured grant type; receive, from the sidelink user equipment, at least one message comprising sidelink traffic characteristics and sidelink discontinuous reception configuration related information.

24. The apparatus of claim 23, wherein the physical sidelink control channel resource allocation is further configured to be valid while the sidelink user equipment is in a radio resource control connected state.

25. The apparatus of claim 23 or 24, wherein the physical sidelink control channel resource allocation is configured to be valid at least within a configured validity area comprising the apparatus.

26. The apparatus of claim 23 or 24, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to transmit the physical sidelink control channel resource allocation by: receiving, from the sidelink user equipment, at least one message comprising at least one of: sidelink traffic characteristics, sidelink DRX configuration related information, or a request for physical sidelink control channel resource allocation; and in response, transmitting the allocation of the one or more physical sidelink control channel resources while in a radio resource control connected state.

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