Method executed by user equipment, and user equipment

Abstract

Provided in the present invention are a method executed by a user equipment, and a user equipment. The method comprises: a sidelink user equipment receiving sidelink control information (SCI) and a corresponding physical sidelink shared channel (PSSCH); and the user equipment determining a start time of a sidelink discontinuous reception (SL DRX) round-trip time (RTT) timer. Thus, the reception power consumption of a sidelink user equipment on an unlicensed spectrum can be reduced.

Description

Methods executed by user equipment and user equipment Technical Field

[0001] This invention relates to the field of wireless communication technology, and more particularly to a method performed by a user equipment and a corresponding user equipment. Background Technology

[0002] In traditional cellular networks, all communication must pass through a base station. In contrast, D2D (Device-to-Device) communication refers to direct communication between two user devices without the need for a base station or core network. At the RAN#63 plenary meeting of the 3rd Generation Partnership Project (3GPP) in March 2014, a research project on implementing proximity D2D communication services using LTE equipment was approved (see Non-Patent Literature 1). The features introduced by LTE Release 12 D2D include:

[0003] 1) Discovery function between nearby devices in LTE network coverage scenarios;

[0004] 2) Direct broadcast communication function between nearby devices;

[0005] 3) The upper layer supports unicast and groupcast communication functions.

[0006] At the 3GPP RAN#66 plenary meeting in December 2014, the research project on enhanced LTE eD2D was approved (see Non-Patent Literature 2). The main features introduced by LTE Release 13 eD2D include:

[0007] 1) D2D discovery in scenarios with no network coverage and scenarios with partial network coverage;

[0008] 2) Priority handling mechanism for D2D communication.

[0009] Based on the D2D communication mechanism, a feasibility study for V2X based on D2D communication was approved at the 3GPP RAN#68 plenary meeting in June 2015. V2X stands for Vehicle to Everything, aiming to enable vehicles to interact with all entities that might affect them, with the goal of reducing accidents, alleviating traffic congestion, reducing environmental pollution, and providing other information services. The main application scenarios of V2X include four aspects:

[0010] 1) V2V, Vehicle to Vehicle, i.e., vehicle-to-vehicle communication;

[0011] 2) V2P, Vehicle to Pedestrian, refers to vehicles sending warnings to pedestrians or non-motorized vehicles;

[0012] 3) V2N, Vehicle to Network, refers to vehicles connecting to mobile networks;

[0013] 4) V2I, Vehicle to Infrastructure, refers to communication between vehicles and road infrastructure.

[0014] 3GPP divides V2X research and standardization work into three phases. The first phase, completed in September 2016, primarily focused on V2V, based on LTE Release 12 and Release 13 D2D (also known as sidelink communication), i.e., the development of proximity communication technology (see Non-Patent Document 3). V2X stage 1 introduced a new D2D communication interface called the PC5 interface. The PC5 interface is mainly used to solve the communication problems of cellular vehicle networks in high-speed (up to 250 km / h) and high-node-density environments. Vehicles can exchange information such as location, speed, and direction through the PC5 interface, meaning vehicles can communicate directly with each other via the PC5 interface. Compared to proximity communication between D2D devices, the functions introduced by LTE Release 14 V2X mainly include:

[0015] 1) Higher density DMRS to support high-speed scenarios;

[0016] 2) Introduce sub-channels to enhance resource allocation methods;

[0017] 3) Introduce a user equipment sensing mechanism with semi-persistent scheduling.

[0018] The second phase of the V2X research project falls under the research scope of LTE Release 15 (see Non-Patent Document 4). The main features introduced include high-order 64QAM modulation, V2X carrier aggregation, and short TTI transmission, while also including a feasibility study of transmit diversity.

[0019] At the 3GPP RAN#80 plenary meeting in June 2018, the corresponding Phase III V2X feasibility study project based on 5G NR network technology (see Non-Patent Document 5) was approved.

[0020] In the 5G NR V2X project, a user equipment-aware resource allocation mode 2 (or transmission mode 2) is supported. In user equipment-aware resource allocation mode 2, the physical layer of the user equipment senses the transmission resources within the resource pool. This means that the user equipment, based on the indication information received from the SCI sent by other user equipment, determines whether to exclude resources in the candidate resource set that overlap with the resources indicated by the aforementioned indication information. Resources not excluded from the candidate resource set are reported to the higher layer, which then randomly selects resources from the reported resource set for PSSCH / PSCCH transmission.

[0021] At the 3GPP RAN#90e plenary meeting in December 2020, a standardization research project on NR sidelink enhancement (see Non-Patent Document 6) was approved. The sidelink enhancement includes the following three aspects:

[0022] 1) Standardize resource allocation methods to reduce power consumption of user equipment in side-line communication, including but not limited to: resource allocation methods based on partial sensing and resource allocation methods based on random resource selection;

[0023] 2) Research on improving the communication reliability and reducing the communication latency of resource allocation method 2 in NR side-channel communication, including: inter-UE coordination. Inter-UE coordination means that UE A determines a resource set and sends (instructions) to UE B regarding that resource set. UE B uses resource allocation method 2 and takes into account the resource set indicated by UE A when selecting resources;

[0024] 3) Standardized Discontinuous Reception (SL DRX) Mechanism. In 5G NR communication, user equipment supports discontinuous reception of the Physical Downlink Control Channel (PDCCH), known as DRX, which can effectively reduce the power consumption of communication equipment. Similarly, corresponding to SL DRX, discontinuous reception refers to listening to the Sidelink Control Information (SCI) (including Level 1 and Level 2 SCI) for a portion of the time domain; this time is called the active time.

[0025] At the 3GPP RAN1#104bis-e meeting in April 2021, the following conclusions were reached regarding Inter-UE coordination in mode 2 (IUC) under resource allocation mode 2 (see Non-Patent Literature 7):

[0026] The following two schemes are supported in collaboration between UEs:

[0027] ○ UE-to-UE Coordination Scheme 1: The coordination message sent by UE A to UE B is an indication of a resource set. This resource set consists of resources preferred for UE B's transmission, and / or resources not preferred for UE B's transmission.

[0028] ○ UE-to-UE Coordination Scheme 2: The coordination message sent by UE A to UE B indicates that there is an expected (or potential) resource conflict on the resource indicated by the SCI sent by UE B, and / or indicates that there is a detected resource conflict on the resource indicated by the SCI sent by UE B.

[0029] At the 3GPP RAN#95e plenary meeting in March 2022, a standardization research project on the evolution of NR sidelink communication (NR sidelink evolution, or NR SL evo for short) was approved (see Non-Patent Document 8). The research objectives of NR SL evo include the following aspects:

[0030] 1) Research and standardize NR side-channel communication on unlicensed spectrum, abbreviated as SL-U. SL-U includes both resource allocation method 1 and resource allocation method 2 for NR side-channel communication. This research project specifically includes:

[0031] a. In SL-U, the channel access technology and operations for NR unlicensed spectrum communication (NR-U) are reused. The NR-U channel access technology refers to Listen Before Talk (LBT) technology, which means that before transmitting, the user equipment needs to listen to the channel resources used for transmission. If the channel is idle, transmission will proceed; otherwise, transmission will be abandoned.

[0032] b. Study the design framework of physical channels in side-by-side communication: that is, make necessary modifications to the structure of physical channels in existing NR side-by-side communication to enable SL-U.

[0033] 2) Research and standardize LTE sidelink and NR sidelink co-channel coexistence, i.e., scenarios where LTE sidelink and NR sidelink communication frequencies are the same or overlap. For LTE sidelink and NR sidelink communication devices using the same communication frequency, design an effective resource allocation method so as not to affect the communication of the two types of sidelink communication devices.

[0034] The SL-U supports the SL DRX mechanism described above, which means that when performing sideline communication on unlicensed spectrum, the user equipment can listen to the sideline communication control information (SCI) (including level 1 SCI and level 2 SCI) for a portion of the time domain.

[0035] The co-channel coexistence supports the UE-to-UE coordination mechanism described above, meaning that the NR side-channel communication module of the side-channel communication user equipment can still combine the coordination messages (e.g., the transmission of the preferred set of resources) in the UE-to-UE coordination to perform resource selection or resource reselection.

[0036] The solutions in this patent include a method for determining the start time of the SL DRX round-trip timer (RTT timer) in the SL-U side-line communication user equipment, and a method for the NR side-line communication module to perform resource selection (or resource reselection) in co-channel coexistence.

[0037] Existing technical documents

[0038] Non-patent literature

[0039] Non-patent document 1: RP-140518, Work item proposal on LTE Device to Device Proximity Services

[0040] Non-Patent Document 2: RP-142311, Work Item Proposal for Enhanced LTE Device to Device Proximity Services

[0041] Non-Patent Document 3: RP-152293, New WI proposal: Support for V2V services based on LTE sidelink

[0042] Non-patent literature 4: RP-170798, New WID on 3GPP V2X Phase 2

[0043] Non-Patent Document 5: RP-181480, New SID Proposal: Study on NR V2X

[0044] Non-Patent Literature 6: RP-202846, WID revision: NR sidelink enhancement

[0045] Non-patent literature 7: RAN1#104bis-e, Chairman's notes, section 8.11.1.2

[0046] Non-Patent Literature 8: RP-220300, WID revision: NR sidelink evolution Summary of the Invention

[0047] To address at least some of the above-mentioned problems, the present invention provides a method performed by a user equipment and a user equipment thereof.

[0048] According to a first aspect of the present invention, a method performed by a user equipment (UE) is provided, comprising: the side-link communication UE receiving side-link communication control information (SCI) and a corresponding physical side-link communication shared channel (PSSCH); and the UE determining the start time of a side-link communication discontinuous reception (SL DRX) round-trip timer (RTT timer).

[0049] In the method of the first aspect described above, the sidelink grant associated with the SCI is configured with PSFCH resources.

[0050] In the method of the first aspect described above, the user equipment determines the start time of the SL DRX RTT timer based on the instruction information of the SCI.

[0051] In the method of the first aspect above, if the SCI indicates that the side-link communication HARQ feedback is disabled, and the SCI does not indicate one or more retransmission opportunities, and if a PSCCH / PSSCH transmission is configured to correspond to one or more PSFCH transmission opportunities, then the user equipment starts the SL DRX RTT timer in the first time slot after the end of the last PSFCH transmission opportunity corresponding to the PSSCH transmission.

[0052] In the method of the first aspect above, if the SCI indicates that the side-link communication HARQ feedback is disabled, and the SCI does not indicate one or more retransmission opportunities, and if one PSCCH / PSSCH transmission is not configured to correspond to one or more PSFCH transmission opportunities, then the user equipment starts the SL DRX RTT timer in the time slot following the end of the PSFCH resource corresponding to the PSSCH.

[0053] In the method of the first aspect described above, if the SCI indicates that the side-to-side communication HARQ feedback is disabled, and the SCI indicates one or more retransmission opportunities, then the user equipment starts the SL DRX RTT timer in the time slot following the end of the PSSCH.

[0054] According to a second aspect of the present invention, a user equipment is provided, comprising: a processor; and a memory storing instructions, wherein the instructions, when executed by the processor, perform the method according to any one of the first aspects described above.

[0055] Beneficial effects of the present invention

[0056] In SL-U, the present invention provides a method for determining the start time of the SL DRX round-trip timer (RTT). Specifically, for a PSSCH transmission corresponding to multiple PSFCH transmission opportunities, when the SCI corresponding to the PSSCH transmission indicates that the SL HARQ is disabled and that the SCI does not indicate any retransmission resources, the user equipment starts the SL DRX RTT in the first time slot after the last PSFCH transmission opportunity among the multiple PSFCH transmission opportunities. The present invention ensures that on unlicensed frequency bands, the side-link communication user equipment starts the SL DRX RTT only once for each PSSCH transmission, effectively implementing SL DRX and reducing the power consumption of the side-link communication user equipment.

[0057] Furthermore, the present invention also provides a solution for co-channel coexistence: when the NR side-channel communication module considers the received preferred resource set during resource selection (or resource reselection), if the intersection of the sensed resource set and the preferred resource set is insufficient for selecting HARQ retransmission resources, the NR side-channel communication module can select resources in the sensed resource set that are already selected and located in the first time slot (with a subcarrier spacing of 30kHz) of the two NR SL time slots overlapping with the LTE SL subframe (either initial transmission or retransmission) in the second time slot, as the selected HARQ retransmission resource. The present invention ensures that even if the NR side-channel communication module has already selected resources in the first time slot of the two NR SL time slots overlapping with the LTE SL subframe, resources in the second time slot can still be selected, effectively avoiding reception interference to LTE side-channel communication. Attached Figure Description

[0058] The above and other features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0059] Figure 1 is a schematic diagram illustrating the basic process of a method performed by a user device in Embodiment 1 of the invention.

[0060] Figure 2 is a schematic diagram illustrating the basic process of the method performed by the user equipment in Embodiment 2 of the invention.

[0061] Figure 3 is a block diagram illustrating a user equipment according to an embodiment of the present invention. Detailed Implementation

[0062] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention should not be limited to the specific embodiments described below. Furthermore, for the sake of simplicity, detailed descriptions of well-known technologies not directly related to the present invention have been omitted to prevent confusion in understanding the present invention.

[0063] The following description uses 5G mobile communication systems and their subsequent evolutions as example application environments to specifically describe several embodiments according to the present invention. However, it should be noted that the present invention is not limited to the following embodiments, but is applicable to many other wireless communication systems, such as communication systems after 5G and 4G mobile communication systems before 5G.

[0064] The following describes some of the terms involved in this invention. Unless otherwise specified, the terms used in this invention are as defined herein. The terms given in this invention may be named differently in LTE, LTE-Advanced, LTE-Advanced Pro, NR and later communication systems, but a unified terminology is used in this invention. When applied to a specific system, it can be replaced with the terminology used in the corresponding system.

[0065] 3GPP: 3rd Generation Partnership Project

[0066] LTE: Long Term Evolution

[0067] NR: New Radio, New Wireless, New Air Interface

[0068] PDCCH: Physical Downlink Control Channel

[0069] DCI: Downlink Control Information

[0070] PDSCH: Physical Downlink Shared Channel

[0071] UE: User Equipment

[0072] eNB: evolved NodeB

[0073] gNB: NR base station

[0074] TTI: Transmission Time Interval

[0075] OFDM: Orthogonal Frequency Division Multiplexing

[0076] CP-OFDM: Cyclic Prefix Orthogonal Frequency Division Multiplexing

[0077] C-RNTI: Cell Radio Network Temporary Identifier

[0078] CSI: Channel State Information

[0079] HARQ: Hybrid Automatic Repeat Request.

[0080] CSI-RS: Channel State Information Reference Signal

[0081] CRS: Cell Reference Signal

[0082] PUCCH: Physical Uplink Control Channel

[0083] PUSCH: Physical Uplink Shared Channel

[0084] UL-SCH: Uplink Shared Channel

[0085] CG: Configured Grant, Configuration Scheduling License

[0086] Sidelink: Side-link communication

[0087] SCI: Sidelink Control Information

[0088] PSCCH: Physical Sidelink Control Channel

[0089] MCS: Modulation and Coding Scheme

[0090] RB: Resource Block

[0091] RE: Resource Element

[0092] CRB: Common Resource Block

[0093] CP: Cyclic Prefix

[0094] PRB: Physical Resource Block

[0095] PSSCH: Physical Sidelink Shared Channel

[0096] FDM: Frequency Division Multiplexing

[0097] RRC: Radio Resource Control

[0098] RSRP: Reference Signal Receiving Power

[0099] SRS: Sounding Reference Signal

[0100] DMRS: Demodulation Reference Signal

[0101] CRC: Cyclic Redundancy Check

[0102] PSDCH: Physical Sidelink Discovery Channel

[0103] PSBCH: Physical Sidelink Broadcast Channel

[0104] SFI: Slot Format Indication

[0105] TDD: Time Division Duplexing

[0106] FDD: Frequency Division Duplexing

[0107] SIB: System Information Block

[0108] SIB1: System Information Block Type 1

[0109] SLSS: Sidelink synchronization signal

[0110] PSSS: Primary Sidelink Synchronization Signal

[0111] SSSS: Secondary Sidelink Synchronization Signal

[0112] PCI: Physical Cell ID

[0113] PSS: Primary Synchronization Signal

[0114] SSS: Secondary Synchronization Signal

[0115] BWP: Bandwidth Part

[0116] GNSS: Global Navigation Satellite System

[0117] SFN: System Frame Number

[0118] DFN: Direct Frame Number

[0119] IE: Information Element

[0120] SSB: Synchronization Signal Block

[0121] EN-DC: EUTRA-NR Dual Connection, LTE-NR Dual Connectivity

[0122] MCG: Master Cell Group

[0123] SCG: Secondary Cell Group

[0124] PCell: Primary Cell

[0125] SCell: Secondary Cell

[0126] PSFCH: Physical Sidelink Feedback Channel

[0127] SPS: Semi-Persistant Scheduling

[0128] TA: Timing Advance, uplink timing advance

[0129] PT-RS: Phase-Tracking Reference Signals

[0130] TB: Transport Block

[0131] CB: Code Block

[0132] QPSK: Quadrature Phase Shift Keying

[0133] 16 / 64 / 256 QAM: 16 / 64 / 256 Quadrature Amplitude Modulation.

[0134] AGC: Auto Gain Control

[0135] TDRA (field): Time Domain Resource Assignment.

[0136] FDRA (field): Frequency Domain Resource Assignment.

[0137] ARFCN: Absolute Radio Frequency Channel Number

[0138] SC-FDMA: Single Carrier-Frequency Division Multiple Access

[0139] MAC: Medium Access Control.

[0140] PDU: Protocol Data Unit

[0141] DRX: Discontinuous Reception

[0142] SL-U: Sidelink unlicensed, sidelink communication over unlicensed spectrum

[0143] NR-U: NR unlicensed, NR communication on unlicensed spectrum

[0144] LBT: Listen Before Talk

[0145] TBS: Transport Block Size

[0146] CQI: Channel Quality Information

[0147] CPE: Cyclic Prefix extension.

[0148] RTT: Round Trip Time

[0149] The following is a description of prior art associated with the present invention. Unless otherwise specified, the same terms in the specific embodiments have the same meaning as in the prior art.

[0150] It is worth noting that V2X and sidelink have the same meaning in this specification. V2X can also mean sidelink in this document; similarly, sidelink can also mean V2X, and no specific distinction or limitation will be made thereafter.

[0151] The resource allocation method for V2X (sidelink) communication and the transmission mode for V2X (sidelink) communication in this specification can be used interchangeably. The resource allocation method mentioned in the specification can represent a transmission mode, and vice versa. In NR sidelink communication, transmission mode 1 represents a transmission mode (resource allocation method) based on base station scheduling; transmission mode 2 represents a transmission mode (resource allocation method) based on user equipment sensing and resource selection.

[0152] In this invention's specification, PSCCH is used to carry SCI. The terms "corresponding," "related," "associated," or "scheduled" PSSCH used in this specification all have the same meaning: associated PSSCH or corresponding PSSCH. Similarly, the terms "associated," "related," or "supposed" SCI (including first-level SCI and second-level SCI) used in this specification all have the same meaning: associated SCI or corresponding SCI. It is worth noting that the first-level SCI is called 1st-stage SCI or SCI format 1-A, and is transmitted in the PSCCH; the second-level SCI is called 2nd-stage SCI or SCI format 2-A (or SCI format 2-B), and is transmitted in the resources of the corresponding PSSCH.

[0153] The NR side-link communication (SL-U) on the unlicensed spectrum described in this invention can also be called shared spectrum channel access. That is, on the unlicensed spectrum, there may be user equipment accessing the channel through Wi-Fi technology (wireless local area network technology based on the IEEE 802.11 standard), and there may also be NR side-link communication user equipment accessing through the PC5 interface.

[0154] The parameter set (numerology) in NR (including NR sidelinks) and the time slot in NR (including NR sidelinks).

[0155] The parameter set numberology includes two aspects: subcarrier spacing and cyclic prefix (CP) length. NR supports five subcarrier spacings: 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz (corresponding to μ = 0, 1, 2, 3, 4). Table 4.2-1 shows the supported transmission parameter set, as detailed below.

[0156] Table 4.2-1 Subcarrier Spacing Supported by NR

[0157] Extended CP is supported only when μ = 2, i.e., a 60kHz subcarrier spacing; other subcarrier spacings only support normal CP. For normal CP, each slot contains 14 OFDM symbols; for extended CP, each slot contains 12 OFDM symbols. For μ = 0 (15kHz subcarrier spacing), one slot = 1ms; for μ = 1 (30kHz subcarrier spacing), one slot = 0.5ms; for μ = 2 (60kHz subcarrier spacing), one slot = 0.25ms, and so on.

[0158] NR and LTE use the same definition for subframes, which is 1ms. For a subcarrier spacing configuration μ, the slot number within one subframe (1ms) can be represented as... The range is 0 to The slot number within a system frame (10ms in duration) can be represented as: The range is 0 to in, and The definitions for different subcarrier spacings μ are shown in the table below.

[0159] Table 4.3.2-1: Number of symbols per slot, number of slots per system frame, and number of slots per subframe during normal CP.

[0160] Table 4.3.2-2: Number of symbols per slot, number of slots per system frame, and number of slots per subframe during extended CP (60kHz)

[0161] On NR carriers, the System Frame Number (SFN) ranges from 0 to 1023. In sidelink communication, the concept of Direct System Frame Number (DFN) is introduced, also ranging from 0 to 1023. The above description of the relationship between system frames and numbers also applies to direct system frames. For example, a direct system frame has a duration of 10 ms, and for a subcarrier spacing of 15 kHz, a direct system frame includes 10 time slots, and so on. DFNs are used for timing on sidelink carriers.

[0162] Resource blocks (RBs) and resource units (REs)

[0163] Resource blocks (RBs) are defined in the frequency domain as For consecutive subcarriers, for example, with a subcarrier spacing of 15 kHz, RB is 180 kHz in the frequency domain. For a subcarrier spacing of 15 kHz × 2 μ Resource element (RE) represents one subcarrier in the frequency domain and one OFDM symbol in the time domain.

[0164] Sidelink communication scenarios

[0165] 1) Out-of-Coverage sidelink communication: Neither of the two UEs conducting sidelink communication has network coverage (for example, if the UE cannot detect any cells that meet the "cell selection criteria" on the frequency where sidelink communication is required, it means that the UE has no network coverage).

[0166] 2) In-Coverage Sidelink Communication: Both UEs performing sidelink communication have network coverage (for example, if a UE detects at least one cell that meets the "cell selection criteria" on the frequency where sidelink communication is required, it means that the UE has network coverage).

[0167] 3) Partial-Coverage Sidelink Communication: One UE in the sidelink communication has no network coverage, while the other UE has network coverage.

[0168] From the UE's perspective, this UE only has two scenarios: no network coverage and network coverage. Partial network coverage is described from the perspective of sidelink communication.

[0169] Sidelink resource pool

[0170] In sidelink communication, the resources used for both transmission and reception by the UE belong to the resource pool. For example, in a base station-scheduled transmission mode in sidelink communication, the base station schedules transmission resources for the sidelink UE from the resource pool; or, in a UE-aware transmission mode in sidelink communication, the UE determines the transmission resources from the resource pool.

[0171] For NR side-channel communication, resource allocation in the frequency domain is supported with sub-channels as the smallest granularity. That is, for PSSCH transmission, the resources occupied in the frequency domain are an integer number of sub-channels. A sub-channel can represent several consecutive resource blocks (RBs) in the frequency domain.

[0172] Perception-based resource allocation

[0173] For the sensing-based resource allocation method (resource allocation method 2), the sidelink communication user equipment selects candidate resources within a time window (optionally, a resource selection window [n+T1, n+T2]), and determines candidate resources that overlap with the reserved resources indicated by the PSCCH sent by other user equipment in the listening time slot, and excludes these overlapping candidate resources. The physical layer reports (or instructs) the set of candidate resources that have not been excluded to the MAC layer, and the MAC layer selects transmission resources for the PSSCH / PSCCH. It is worth noting that when the physical layer reports or instructs the resource set to the MAC layer, it can also be referred to as the user equipment having sensing results in this specification. The set of transmission resources selected by the MAC layer is called the selected sidelink grant. The sidelink communication resources contained in a selected sidelink grant can be used for the initial transmission and all retransmissions of a MAC PDU (corresponding to a transport block TB), or can be used for the initial transmission and all retransmissions of multiple MAC PDUs (corresponding to multiple transport blocks TB). This invention does not impose any limitations on this.

[0174] Resource selection window [n+T1, n+T2]

[0175] In the sensing-based (or partially sensing) resource allocation method, the higher layer requests or triggers the physical layer to determine the resources for PSSCH / PSCCH transmission on time slot n (performing sensing or partial sensing). The resource selection window is defined as [n+T1, n+T2], meaning the user equipment selects transmission resources within this window. Where T1 satisfies the condition... The choice of T1 depends on the user equipment implementation; the RRC configuration information contains a configuration list of resource selection windows, sl-SelectionWindowList, where each priority corresponds to a given priority. TX The element representing the priority of PSSCH transmission is T. 2min If the T 2min If the delay is less than the remaining packet delay budget (remaining PDB), then T2 satisfies condition T. 2min ≤T2≤remaining PDB, the choice of T2 depends on the implementation of the user device; otherwise, T2 is set to remaining PDB. The definition is as follows (μ) SL This represents the subcarrier spacing parameter for side-by-side communication, i.e., the subcarrier spacing is... ):

[0176] Table 8.1.4-2: The value of

[0177] Table 8.1.4-1: The value of

[0178] Physical Side-to-Side Communication Feedback Channel (PSFCH)

[0179] In sideline communication, the PSFCH is used to carry HARQ feedback (HARQ-ACK). For example, the sending user equipment sends PSSCH and PSCCH. If the receiving user equipment correctly receives and decodes the PSCCH and PSSCH, it sends an ACK on the PSFCH; otherwise, it sends a NACK.

[0180] LBT (Listen Before Talk) mechanism

[0181] For wireless communication on unlicensed spectrum, some countries or regions (e.g., Europe) require user equipment to perform LBT (Listen-Before-Speak) operation before transmitting wirelessly. This is also known as channel access operation, which involves sensing the channel to determine its availability. Specifically, for a period before communication transmission, the user equipment will only transmit if it detects that the channel is idle; otherwise, it will not transmit.

[0182] Specifically, for NR communication (NR-U) on unlicensed spectrum (or, for SL-U), the basic time unit of the sensing channel can be T. sl = 9μs. Within this time unit, if the energy detected by the base station or user equipment on the channel is lower than the energy threshold value X... ThreshWhen the duration is equal to or exceeds 4 μs, the base station or user equipment considers the channel to be idle within that time unit (or, referred to as LBT success). It is worth noting that the channel used by the base station or user equipment to detect energy and determine idleness represents a carrier containing a continuous set of resource blocks (RBs), or a portion of that carrier. This channel can also be called the LBT bandwidth, LBT sub-band, or RB set. An LBT bandwidth or RB set can be equal to 20 MHz in the frequency domain, meaning that an RB set can exist on a 20 MHz carrier. The number of resource blocks (RBs) corresponding to multiple RB sets contained on a carrier (carriers exceeding 20 MHz, such as 40 MHz, 60 MHz, 80 MHz) and the guard band (GB) between two consecutive RB sets can be as shown in the table below:

[0183] Table 1: All RB sets and the number of RBs contained in a GB on a single carrier at 15kHz and 30kHz subcarrier spacing.

[0184] In the diagram above, taking a subcarrier spacing of 15kHz and a carrier bandwidth of 40MHz as an example, 105-6-105 indicates that the carrier contains two consecutive RB sets, each containing 105 RBs. Between these two RB sets, there is a guard band (GB) containing 6 consecutive RBs, for a total of 216 consecutive RBs, and so on for the other items in Table 1.

[0185] It is worth noting that LBT operations performed by a (side-line communication) user equipment on different RB sets can be independent of each other (i.e., the two are unrelated). For example, a user equipment may detect that the channel is idle on RB set 1, but detect that the channel is occupied (or busy) on RB set 2. If a side-line communication user equipment selects resources for transmitting PSSCH / PSCCH that simultaneously include (all or part of) the RBs corresponding to RB set 1 and RB set 2, the user equipment may transmit the corresponding PSSCH / PSCCH if and only if the user equipment detects that the channel is idle on both RB set 1 and RB set 2.

[0186] Side-line communication discontinuous reception of SL DRX and round-trip timer RTT timer

[0187] For SL DRX, the user equipment in side-line communication listens to the PSCCH during the active time; during the in-active time, the user equipment does not need to listen to the PSCCH.

[0188] In SL DRX, user equipment uses timers (running or timed out) to determine whether the current time is an active or inactive period. For the Round-Trip Timer (RTT), it indicates that while the timer is running, the user equipment assumes the peer user equipment will not send a PSCCH to schedule retransmissions, or engage in other sideline communication transmissions. Therefore, before the RTT timer expires, the user equipment is in an inactive period and will not listen to the PSCCH. The RTT timer generally represents the minimum duration for which the user equipment assumes the peer user equipment will not schedule retransmissions.

[0189] In the specification of this invention, timer timeout means that the timer runs for longer than its duration, which is referred to as timer expires.

[0190] A PSCCH / PSSCH transmission corresponds to N associated candidate PSFCH resources (or, transmission opportunities).

[0191] For side-channel communication on unlicensed spectrum, LBT failure may prevent PSFCH transmission. Therefore, for SL-U, one PSCCH / PSSCH transmission can correspond to N associated candidate PSFCH resources. That is, if the LBT of one candidate PSFCH resource fails, the LBT of one or more other candidate PSFCH resources may succeed, allowing PSFCH transmission. N is determined by configuration or pre-configuration information (the corresponding RRC parameter is numPSFCHOccasions), and its value ranges from {1, 2, 3, 4}. Specifically, the N associated candidate PSFCH resources corresponding to one PSCCH / PSSCH transmission are located in the same RB set across different time slots.

[0192] Side-line communication user equipment with dual module

[0193] In scenarios where LTE and NR sidelinks co-channel coexist, at least one sidelink user equipment (UHMA) equipped with both LTE and NR sidelink communication modules is supported. This means the UHMA can perform both LTE and NR sidelink transmission and reception functions. It's worth noting that in this type of UHMA, the LTE sidelink module can share (or indicate) information with the NR sidelink module. This information can include LTE sidelink resource reservation information or sensing information. The NR sidelink module can also obtain LTE sidelink resource pool configuration information, LTE sidelink SLSS configuration information, etc., meaning that this includes, but is not limited to, information that does not need to be shared (or indicated) by the LTE sidelink module. In co-channel coexistence, NR SL only supports subcarrier spacing of 15kHz or 30kHz. When the subcarrier spacing of NR SL is 30kHz, if the LTESL subframe boundary and the NR SL subframe boundary overlap, then one LTE SL subframe (1ms) overlaps with two consecutive NR SL time slots in the time domain (the duration of one NR SL time slot is 0.5ms).

[0194] Inter-UE coordination (IUC)

[0195] The following two schemes are supported in collaboration between UEs:

[0196] ■ UE-to-UE Coordination Scheme 1: The coordination message sent by UE A to UE B is an indication of a resource set. This resource set is either a preferred resource set for UE B's transmissions, or a non-preferred resource set for UE B's transmissions.

[0197] ■ UE Inter-Symbol Collaboration Scheme 2: The collaboration message sent by UE A to UE B indicates that there is an expected (or potential) resource conflict on the resource indicated by the SCI sent by UE B, and / or indicates that there is a detected resource conflict on the resource indicated by the SCI sent by UE B.

[0198] The following provides a detailed description of specific examples and embodiments related to this invention. Furthermore, as described above, the examples and embodiments described in this disclosure are illustrative and intended to facilitate understanding of the invention, and are not intended to limit the scope of the invention.

[0199] [Example 1]

[0200] Figure 1 is a schematic diagram illustrating the basic process of a method executed by a user equipment according to Embodiment 1 of the present invention.

[0201] The method executed by the user equipment in Embodiment 1 of the present invention will now be described in detail with reference to the basic process diagram shown in Figure 1.

[0202] As shown in Figure 1, in Embodiment 1 of the present invention, the steps performed by the user equipment include:

[0203] In step S101, the side-link communication user equipment receives the side-link communication control information SCI and the corresponding physical side-link communication shared channel PSSCH.

[0204] The sidelink grant associated with the SCI is configured with sidelink communication HARQ feedback resources (i.e., PSFCH resources are configured).

[0205] In step S102, the user equipment determines the start time of the side-line communication discontinuous reception (SL DRX) round-trip timer (RTT timer).

[0206] Optionally, the user equipment determines the start time of the SL DRX RTT timer based on the instruction information of the SCI.

[0207] Optionally, if the SCI indicates that the side-to-side communication HARQ feedback is disabled, and the SCI does not indicate one or more retransmission opportunities,

[0208] So,

[0209] If (the sidelink grant, or the SCI, or the resource pool associated with the sidelink grant or the SCI) is configured to provide one or more PSCCH / PSSCH transmission opportunities corresponding to a PSFCH transmission opportunity (i.e., numPSFCHOccasions is configured),

[0210] So,

[0211] The user equipment starts the SL DRX RTT timer in the first time slot after the end of the last PSFCH transmission opportunity (or the last PSFCH resource) (corresponding to the PSSCH transmission);

[0212] otherwise,

[0213] The user equipment starts the SL DRX RTT timer in the following time slot after the end of the PSFCH resource (corresponding to the PSSCH).

[0214] Optionally, if the SCI indicates that the side-by-side communication HARQ feedback is disabled, and the SCI indicates one or more retransmission opportunities,

[0215] So,

[0216] The user equipment starts the SL DRX RTT timer in the time slot following the end of the PSSCH.

[0217] [Example 2]

[0218] Figure 2 is a schematic diagram illustrating the basic process of a method executed by a user equipment according to Embodiment 2 of the present invention.

[0219] The method executed by the user equipment in Embodiment 2 of the present invention will now be described in detail with reference to the basic process diagram shown in Figure 2.

[0220] As shown in Figure 2, in Embodiment 2 of the present invention, the steps performed by the user equipment include:

[0221] In step S201, the physical layer of the side-link communication user equipment indicates (or reports) a set of (candidate) resources to the MAC layer.

[0222] The indication may also be referred to as the user equipment possessing sensing results.

[0223] In step S202, the user equipment performs resource selection or resource reselection.

[0224] Optionally, the user equipment selects one or more HARQ retransmissions.

[0225] Optionally, if UE-to-UE coordination scheme one is enabled (i.e., RRC is configured with sl-InterUE-CoordinationScheme), and the user equipment receives a preferred resource set for transmission, and,

[0226] For the scenario where NR side-channel communication and LTE side-channel communication co-channel coexistence (i.e., RRC is configured with sl-NRPSSCH-EUTRA-ThresRSRP-List), and,

[0227] The subcarrier spacing for the NR side-link communication is 30kHz, then,

[0228] The user equipment selects a first time-frequency resource for a transmission opportunity.

[0229] Optionally, the first transmission opportunity is the initial transmission opportunity.

[0230] Optionally, the first time-frequency resource is located in the time domain on the first of two consecutive NR side-link communication time slots that coincide with the LTE side-link communication subframe, and,

[0231] If there are remaining (left) available resources in the intersection of the (candidate) resource set and the preferred resource set for the one or more HARQ retransmission opportunities, then the user equipment selects a second time-frequency resource for the one or more HARQ retransmission opportunities.

[0232] Optionally, the second time-frequency resource is located in the time domain on the second time slot of the two consecutive NR side-link communication time slots that overlap with the LTE side-link communication subframe corresponding to the first time-frequency resource (that is, the first time slot of the two consecutive NR side-link communication time slots that overlap with the LTE side-link communication subframe corresponds to the first time-frequency resource, and the second time slot corresponds to the second time-frequency resource).

[0233] If the number of second time-frequency resources (which has been maximally selected) is less than the number of selected HARQ retransmissions, and if there are remaining available resources in the (candidate) resource set for the one or more HARQ retransmission opportunities, then the user equipment selects a third time-frequency resource for the one or more HARQ retransmission opportunities.

[0234] Optionally, the third time-frequency resource is located in the time domain on the second of the two consecutive NR side-link communication time slots that coincide with the LTE side-link communication subframe, corresponding to the already selected time-frequency resource (the first time-frequency resource and / or the second time-frequency resource).

[0235] Figure 3 is a block diagram illustrating the user equipment (UE) according to the present invention. As shown in Figure 3, the UE 80 includes a processor 801 and a memory 802. The processor 801 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 802 may include, for example, volatile memory (such as random access memory, RAM), a hard disk drive (HDD), non-volatile memory (such as flash memory), or other memory. Program instructions are stored on the memory 802. When executed by the processor 801, these instructions can perform the methods described in detail in this invention, which are executed by the user equipment.

[0236] The method and related apparatus of the present invention have been described above in conjunction with preferred embodiments. Those skilled in the art will understand that the methods shown above are merely exemplary, and the various embodiments described above can be combined with each other without contradiction. The method of the present invention is not limited to the steps and sequence shown above. The network nodes and user equipment shown above may include more modules, such as modules that can be developed or will be developed in the future for use with base stations, MMEs, or UEs, etc. The various identifiers shown above are merely exemplary and not limiting, and the present invention is not limited to the specific information elements exemplified by these identifiers. Those skilled in the art can make many variations and modifications based on the teachings of the illustrated embodiments.

[0237] It should be understood that the above embodiments of the present invention can be implemented by software, hardware, or a combination of both. For example, the various components inside the base station and user equipment in the above embodiments can be implemented by a variety of devices, including but not limited to: analog circuit devices, digital circuit devices, digital signal processing (DSP) circuits, programmable processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices (CPLDs), and so on.

[0238] In this application, "base station" can refer to a mobile communication data and control switching center with high transmission power and wide coverage, including functions such as resource allocation and scheduling, and data reception and transmission. "User equipment" can refer to user mobile terminals, such as mobile phones, laptops, and other terminal devices that can wirelessly communicate with base stations or micro base stations.

[0239] Furthermore, the embodiments of the present invention disclosed herein can be implemented on a computer program product. More specifically, the computer program product is one that has a computer-readable medium on which computer program logic is encoded, which, when executed on a computing device, provides related operations to implement the above-described technical solutions of the present invention. When executed on at least one processor of a computing system, the computer program logic causes the processor to perform the operations (methods) described in the embodiments of the present invention. This configuration of the present invention is typically provided as software, code, and / or other data structures disposed or encoded on a computer-readable medium such as an optical medium (e.g., CD-ROM), floppy disk, or hard disk, or other media such as firmware or microcode on one or more ROM, RAM, or PROM chips, or downloadable software images, shared databases, etc., in one or more modules. The software or firmware or such configuration can be installed on a computing device to cause one or more processors in the computing device to execute the technical solutions described in the embodiments of the present invention.

[0240] Furthermore, each functional module or feature of the base station equipment and terminal equipment used in each of the above embodiments can be implemented or executed by circuitry, which is typically one or more integrated circuits. Circuitry designed to perform the various functions described in this specification may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs) or general-purpose integrated circuits, field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, or discrete hardware components, or any combination of the above devices. The general-purpose processor may be a microprocessor, or the processor may be an existing processor, controller, microcontroller, or state machine. The aforementioned general-purpose processor or each circuit may be configured by digital circuitry or by logic circuitry. Furthermore, when advancements in semiconductor technology lead to advanced technologies that can replace current integrated circuits, the present invention may also utilize integrated circuits obtained using such advanced technologies.

[0241] Although the present invention has been illustrated above with reference to preferred embodiments, those skilled in the art will understand that various modifications, substitutions, and alterations can be made to the invention without departing from its spirit and scope. Therefore, the invention should not be limited by the above embodiments, but rather by the appended claims and their equivalents.

Claims

1. A method executed by a user equipment, comprising: The side-link communication user equipment receives side-link communication control information (SCI) and the corresponding physical side-link communication shared channel (PSSCH). If the SCI indicates that the side-by-side HARQ feedback is disabled, and the SCI does not indicate one or more retransmission opportunities, as well as, If one PSCCH / PSSCH transmission is configured to correspond to one or more PSFCH transmission opportunities, then... The user equipment starts the SL DRX RTT timer in the first time slot after the end of the last PSFCH transmission opportunity corresponding to the PSSCH transmission.

2. A user equipment, comprising: processor; as well as Memory, which stores instructions The instructions are executed by the processor according to the method of claim 1.

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