METHOD PERFORMED BY USER EQUIPMENT, AND USER EQUIPMENT

Abstract

Provided in the present invention are a method performed by user equipment and user equipment. The method includes: requesting or triggering, by a higher layer, the user equipment to determine a resource subset for PSSCH/PSCCH transmission; determining, by the user equipment, a set of candidate slots; and determining, by the user equipment, the number Q of sidelink control information (SCI) assumed to be received that are identical to SCI received in a slot (I).

Description

TECHNICAL FIELD

The present invention relates to the technical field of wireless communications, and in particular to a method performed by user equipment, and corresponding user equipment.

BACKGROUND

In conventional cellular networks, all communication needs to pass through base stations. By contrast, D2D communication (device-to-device communication) refers to a means of communication in which two user equipment units directly communicate with each other without needing to pass through a base station or needing a core network to perform forwarding therebetween. A research project on the use of LTE equipment to implement proximity D2D communication services was approved at the 3rd Generation Partnership Project (3GPP) RAN #63 plenary meeting in March 2014 (see Non-Patent Document 1). Functions introduced in the LTE Release 12 D2D include:

• • 1) a discovery function between proximate devices in an LTE network coverage scenario;
  • 2) a direct broadcast communication function between proximate devices; and
  • 3) support for unicast and groupcast communication functions at higher layers.

A research project on enhanced LTE eD2D (enhanced D2D) was approved at the 3GPP RAN #66 plenary meeting in December 2014 (see Non-Patent Document 2). Main functions introduced in the LTE Release 13 eD2D include:

• • 1) D2D discovery in out-of-coverage and partial-coverage scenarios; and
  • 2) a priority handling mechanism for D2D communication.

Based on the design of the D2D communication mechanism, a V2X feasibility research project based on D2D communication was approved at the 3GPP RAN #68 plenary meeting in June 2015. V2X stands for Vehicle to Everything, and is used to implement information exchange between a vehicle and all entities that may affect the vehicle, for the purpose of reducing accidents, alleviating traffic congestion, reducing environmental pollution, and providing other information services. Application scenarios of V2X mainly include four aspects:

• • 1) V2V, Vehicle to Vehicle, i.e., vehicle-to-vehicle communication;
  • 2) V2P, Vehicle to Pedestrian, i.e., a vehicle transmits alarms to a pedestrian or a non-motorized vehicle;
  • 3) V2N: Vehicle-to-Network, i.e., a vehicle connects to a mobile network;
  • 4) V2I: Vehicle-to-Infrastructure, i.e., communication such as that between a vehicle and road infrastructure.

3GPP divides the research and standardization of V2X into three stages. The first stage was completed in September 2016, and mainly focused on V2V and was based on LTE Release 12 and Release 13 D2D (also known as sidelink), that is, the development of proximity communication technologies (see Non-Patent Document 3). V2X stage 1 introduced a new D2D communication interface referred to as a PC5 interface. The PC5 interface is mainly used to address the issue of cellular Internet of Vehicle (IoV) communication in high-speed (up to 250 km/h) and high-node density environments. Vehicles can exchange information such as position, speed, and direction through the PC5 interface, that is, the vehicles can communicate directly through the PC5 interface. Compared with the proximity communication between D2D devices, functions introduced in LTE Release 14 V2X mainly include:

• • 1) higher density DMRS to support high-speed scenarios;
  • 2) introduction of sub-channels to enhance resource allocation methods; and
  • 3) introduction of a user equipment sensing mechanism having semi-persistent scheduling.

The second stage of the V2X research project belonged to the LTE Release 15 research category (see Non-Patent Document 4). Main features introduced included high-order 64QAM modulation, V2X carrier aggregation, short TTI transmission, as well as feasibility study of transmit diversity.

The corresponding third stage, a V2X feasibility research project based on 5G NR network technologies (see Non-Patent Document 5), was approved at the 3GPP RAN #80 plenary meeting in June 2018.

In the 5G NR V2X project, user equipment sensing-based resource allocation mode 2, or referred to as transmission mode 2, is supported. In resource allocation mode 2, the physical layer of the user equipment senses transmission resources in a resource pool, and reports a set of available transmission resources to the upper layers. After acquiring the report from the physical layer, the upper layers select a specific resource for sidelink transmission.

In 5G NR V2X, a pre-emption check mechanism is supported. The pre-emption check means that after the MAC layer selects a resource for sidelink transmission, sensing is performed again on the selected transmission resource at a certain future moment, so as to determine whether the resource has been reserved or pre-empted by other user equipment. If the transmission resource has been reserved or pre-empted by the other user equipment, the MAC layer may trigger resource reselection for the resource, to replace the transmission resource pre-empted by the other user equipment.

A standardization study project based on standardized NR sidelink enhancement (see Non-Patent Document 6) was approved at the 3GPP RAN #90e plenary meeting in December 2020. The sidelink enhancement includes the following two aspects:

• • 1) Standard resource allocation modes for power consumption reduction (power saving) of sidelink user equipment include, but are not limited to: a resource allocation mode based on partial sensing, and a resource allocation mode based on random resource selection.
  • 2) Research to improve communication reliability of resource allocation mode 2 in NR sidelink and reduction in communication latency of resource allocation mode 2.

In the user equipment sensing-based resource allocation mode 2 described above, the physical layer of the user equipment senses transmission resources in a resource pool, which means that the user equipment, according to indication information in received SCI transmitted by other user equipment, excludes a resource that is in a set of candidate resources and that overlaps with a resource indicated by the indication information, and resources, which are not excluded, in the set of candidate resources are reported to a higher layer.

The solution of the present patent mainly includes a method for sidelink user equipment excluding a resource from a set of candidate resources in a resource allocation mode based on partial sensing.

The study project of NR sidelink enhancement also includes the standardization study work of sidelink (SL) discontinuous reception (SL DRX). In 5G NR communication, user equipment supports temporally discontinuous reception of a physical downlink control channel (PDCCH), referred to as DRX, thereby effectively reducing power consumption of communication devices. Similarly, for SL DRX, discontinuous reception refers to receiving a physical sidelink control channel (PSCCH) within a partial time in the time domain, and the time is referred to as an active time. A time within which no PSCCH is received is referred to as an in-active time.

The solution of the present patent also includes a method for user equipment, when configured with SL DRX, performing resource reselection for a sidelink transmission resource if the sidelink transmission resource is reserved or pre-empted by other user equipment.

PRIOR ART DOCUMENT

Non-Patent Documents

• Non-Patent Document 1: RP-140518, Work item proposal on LTE Device to Device Proximity Services
• Non-Patent Document 2: RP-142311, Work Item Proposal for Enhanced LTE Device to Device Proximity Services
• Non-Patent Document 3: RP-152293, New WI proposal: Support for V2V services based on LTE sidelink
• Non-Patent Document 4: RP-170798, New WID on 3GPP V2X Phase 2
• Non-Patent Document 5: RP-181480, New SID Proposal: Study on NR V2X
• Non-Patent Document 6: RP-202846, WID revision: NR sidelink enhancement

SUMMARY

In order to address at least part of the aforementioned issues, the present invention provides a method performed by user equipment, and user equipment.

A method performed by user equipment according to a first aspect of the present invention, comprising: requesting or triggering, by a higher layer, the user equipment to determine a resource subset for PSSCH/PSCCH transmission; determining, by the user equipment, a set of candidate slots; and determining, by the user equipment, the number Q of sidelink control information (SCI) assumed to be received that are identical to SCI received in a slot t_m′^SL.

In the method performed by user equipment according to the first aspect of the present invention, the higher layer selects a sidelink resource for the PSSCH/PSCCH transmission in the resource subset.

In the method performed by user equipment according to the first aspect of the present invention, a resource allocation mode of the user equipment is a resource allocation mode based on partial sensing.

In the method performed by user equipment according to the first aspect of the present invention, the higher layer requests, in a slot n, the user equipment to determine the resource subset.

In the method performed by user equipment according to the first aspect of the present invention, a resource reservation period indicated by a resource reservation period indication field in the SCI received by the user equipment in the slot t_m′^SL is P_{rsvp_RX}.

In the method performed by user equipment according to the first aspect of the present invention, when a resource selection window is defined as [n+T1, n+T2], and the first slot in the set of candidate slots in the time domain is represented by t_yo′^SL, n+T_B=t_yo′^SL−T_proc,1^SL−T_proc,0^SL, or n+T_B=t_yo′^SL−T_proc,1^SL, or n+T_B=t_yo′^SL−T_proc,0^SL, wherein T_proc,1^SL represents a first processing latency, and T_proc,0^SL represents a second processing latency.

In the method performed by user equipment according to the first aspect of the present invention, if T_B≥T1 or T_B>T1, then: if and only if the resource reservation period indication field is present in the SCI, the user equipment assumes that SCI identical to the SCI is to be received in a slot

$t_{m+q\times P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }}^{{ }_{}\prime \mathrm{SL}};$

if P_{rsvp_RX}<T2−T_B and n′−m≤P′_{rsvp_RX}, then

$Q=\lceil \frac{T2-T_B}{P_{\mathrm{rsvp}\_\mathrm{RX}}}\rceil ,$

otherwise, Q=1; if a slot n+T_B is a slot in the resource pool, then t_n′′^SL=n+T_B, otherwise, t_n′′^SL represents the first slot after the slot n+T_B in the resource pool, or if T_B≤T1 or T_B<T1, then: if and only if the resource reservation period indication field is present in the SCI, the user equipment assumes that SCI identical to the SCI is to be received in a slot

$t_{m+q\times P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }}^{{ }_{}\prime \mathrm{SL}};$

if P_{rsvp_RX}<T2 and n′−m≤P′_{rsvp_RX}, then

$Q=\lceil \frac{T2}{P_{\mathrm{rsvp}\_\mathrm{RX}}}\rceil ,$

otherwise, Q=1; if the slot n is a slot in the resource pool, then t_n′′^SL=n, otherwise, t_n′′^SL represents the first slot after the slot n in the resource pool, wherein q=1, 2, . . . , Q,

$P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }=\lceil \frac{T_{\max }^{{ }_{}\prime }}{10240\mathrm{ms}}\times P_{\mathrm{rsvp}\_\mathrm{RX}}\rceil ,$

T′_max representing the number of slots in SFN/DFN 0 to SFN/DFN 1023 within 10240 ms belonging to the resource pool.

In the method performed by user equipment according to the first aspect of the present invention, when the resource selection window is defined as [n+T1, n+T2], a slot n+T_B represents the first slot after the slot n and separated from the slot n by 31 slots comprised in the resource pool, or the slot n+T_B represents the first slot after the slot n+1 and separated from the slot n+1 by 32 slots comprised in the resource pool.

In the method performed by user equipment according to the first aspect of the present invention, if and only if the resource reservation period indication field is present in the SCI, the user equipment assumes that SCI identical to the SCI is to be received in a slot

$t_{m+q\times P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }}^{{ }_{}\prime \mathrm{SL}},$

and if P_{rsvp_RX}<T2−T_B and n′−m≤P′_{rsvp_RX}, then

$Q=\lceil \frac{T2-T_B}{P_{\mathrm{rsvp}\_\mathrm{RX}}}\rceil ,$

otherwise, Q=1; if a slot n+T_B is a slot in the resource pool, then t_n′′^SL=n+T_B, otherwise, t_n′′^SL represents the first slot after the slot n+T_B in the resource pool, wherein q=1, 2, . . . , Q, and

$P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }=\lceil \frac{T_{\max }^{{ }_{}\prime }}{10240\mathrm{ms}}\times P_{\mathrm{rsvp}\_\mathrm{RX}}\rceil ,$

T′_max representing the number of slots in SFN/DFN 0 to SFN/DFN 1023 within 10240 ms belonging to the resource pool.

User equipment according to a second aspect of the present invention comprises: a processor; and a memory storing instructions, wherein the instructions, when run by the processor, perform any method according to the first aspect of the present invention.

Beneficial Effects of Present Invention

According to the solution of the present patent, in NR sidelink enhancement, for the resource allocation mode based on partial sensing, it can be ensured that when resource excluding is performed, sidelink user equipment also considers a sidelink resource indicated in SCI detected after a triggering slot, which can reduce the probability of sidelink resource conflict and improve sidelink reliability. In addition, according to the solution of the present patent, in NR sidelink enhancement, for user equipment configured with SL DRX, it can be ensured that a resource reselected by user equipment can be received by receiving user equipment in an active time, thereby improving sidelink reliability and effectively reducing power consumption of the receiving user equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will be more apparent from the following detailed description in combination with the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing sidelink communication of LTE V2X UE.

FIG. 2 is a schematic diagram showing a resource allocation mode of LTE V2X.

FIG. 3 is a schematic diagram showing a basic procedure of a method performed by user equipment according to Embodiments 1 and 2 of the invention.

FIG. 4 is a schematic diagram showing a basic procedure of a method performed by user equipment according to Embodiment 3 of the invention.

FIG. 5 is a block diagram showing user equipment according to an embodiment of the present invention.

DETAILED DESCRIPTION

The following describes the present invention 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. In addition, detailed descriptions of well-known technologies not directly related to the present invention are omitted for the sake of brevity, in order to avoid obscuring the understanding of the present invention.

In the following description, a 5G mobile communication system and later evolved versions thereof are used as exemplary application environments to set forth a plurality of embodiments according to the present invention in detail. However, it is to be noted that the present invention is not limited to the following embodiments, but is applicable to many other wireless communication systems, such as a communication system after 5G and a 4G mobile communication system before 5G.

Some terms involved in the present invention are described below. Unless otherwise specified, the terms used in the present invention use the definitions herein. The terms given in the present invention may vary in LTE, LTE-Advanced, LTE-Advanced Pro, NR, and subsequent communication systems, but unified terms are used in the present invention. When applied to a specific system, the terms may be replaced with terms used in the corresponding system.

• • 3GPP: 3rd Generation Partnership Project
  • LTE: Long Term Evolution
  • NR: New Radio
  • PDCCH: Physical Downlink Control Channel
  • DCI: Downlink Control Information
  • PDSCH: Physical Downlink Shared Channel
  • UE: User Equipment
  • eNB: evolved NodeB, evolved base station
  • gNB: NR base station
  • TTI: Transmission Time Interval
  • OFDM: Orthogonal Frequency Division Multiplexing
  • CP-OFDM: Cyclic Prefix Orthogonal Frequency Division Multiplexing
  • C-RNTI: Cell Radio Network Temporary Identifier
  • CSI: Channel State Information
  • HARQ: Hybrid Automatic Repeat Request
  • CSI-RS: Channel State Information Reference signal
  • CRS: Cell Reference Signal
  • PUCCH: Physical Uplink Control Channel
  • PUSCH: Physical Uplink Shared Channel
  • UL-SCH: Uplink Shared Channel
  • CG: Configured Grant
  • Sidelink: Sidelink communication
  • SCI: Sidelink Control Information
  • PSCCH: Physical Sidelink Control Channel
  • MCS: Modulation and Coding Scheme
  • RB: Resource Block
  • RE: Resource Element
  • CRB: Common Resource Block
  • CP: Cyclic Prefix
  • PRB: Physical Resource Block
  • PSSCH: Physical Sidelink Shared Channel
  • FDM: Frequency Division Multiplexing
  • RRC: Radio Resource Control
  • RSRP: Reference Signal Receiving Power
  • SRS: Sounding Reference Signal
  • DMRS: Demodulation Reference Signal
  • CRC: Cyclic Redundancy Check
  • PSDCH: Physical Sidelink Discovery Channel
  • PSBCH: Physical Sidelink Broadcast Channel
  • SFI: Slot Format Indication
  • TDD: Time Division Duplexing
  • FDD: Frequency Division Duplexing
  • SIB1: System Information Block Type 1
  • SLSS: Sidelink Synchronization Signal
  • PSSS: Primary Sidelink Synchronization Signal
  • SSSS: Secondary Sidelink Synchronization Signal
  • PCI: Physical Cell ID
  • PSS: Primary Synchronization Signal
  • SSS: Secondary Synchronization Signal
  • BWP: Bandwidth Part
  • GNSS: Global Navigation Satellite System
  • SFN: System Frame Number (radio frame number)
  • DFN: Direct Frame Number
  • IE: Information Element
  • SSB: Synchronization Signal Block
  • EN-DC: EUTRA-NR Dual Connection
  • MCG: Master Cell Group
  • SCG: Secondary Cell Group
  • PCell: Primary Cell
  • SCell: Secondary Cell
  • PSFCH: Physical Sidelink Feedback Channel
  • SPS: Semi-Persistent Scheduling
  • TA: Timing Advance
  • PT-RS: Phase-Tracking Reference Signal
  • T_B: Transport Block
  • CB: Code Block
  • QPSK: Quadrature Phase Shift Keying
  • 16/64/256 QAM: 16/64/256 Quadrature Amplitude Modulation
  • AGC: Automatic Gain Control
  • TDRA (field): Time Domain Resource Assignment indication (field)
  • FDRA (field): Frequency Domain Resource Assignment indication (field)
  • ARFCN: Absolute Radio Frequency Channel Number
  • SC-FDMA: Single Carrier-Frequency Division Multiple Access
  • MAC: Medium Access Control layer
  • DRX: Discontinuous Reception

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

It is worth pointing out that the V2X and sidelink mentioned in the description of the present invention have the same meaning. The V2X herein can also mean sidelink; similarly, the sidelink herein can also mean V2X, and no specific distinction and limitation will be made in the following text.

The resource allocation mode of V2X (sidelink) communication and the transmission mode of V2X (sidelink) communication in the description of the present invention can equivalently replace each other. The resource allocation mode involved in the description can mean a transmission mode, and the transmission mode involved herein can mean a resource allocation mode. In NR sidelink, transmission mode 1 represents a base station scheduling-based transmission mode (resource allocation mode), and transmission mode 2 represents a user equipment sensing-based and resource selection-based transmission mode (resource allocation mode).

The PSCCH in the description of the present invention is used to carry SCI. The PSSCH associated with or relevant to or corresponding to or scheduled by PSCCH involved in the description of the present invention has the same meaning, and all refer to an associated PSSCH or a corresponding PSSCH. Similarly, the SCI (including first stage SCI and second stage SCI) associated with or relevant to or corresponding to PSSCH involved in the description has the same meaning, and all refer to associated SCI or corresponding SCI. It is worth pointing out that the first stage SCI, referred to as 1st stage SCI or SCI format 1-A, is transmitted in the PSCCH; and the second stage SCI, referred to as 2nd stage SCI or SCI format 2-A (or, SCI format 2-B), is transmitted in resources of the corresponding PSSCH.

Numerologies in NR (Including NR Sidelink) and Slots in NR (Including NR Sidelink)

A numerology includes two aspects: a subcarrier spacing and a cyclic prefix (CP) length. NR supports five subcarrier spacings, which are respectively 15 kHz, 30 kHz, 60 kHz, 120 kHz and 240 kHz (corresponding to μ=0, 1, 2, 3, 4). Table 4.2-1 shows the supported transmission numerologies specifically as follows:

TABLE 4.2-1
Subcarrier Spacings Supported by NR
	μ	Δf = 2μ · 15[kHz]	CP (cyclic prefix)
	0	15	Normal
	1	30	Normal
	2	60	Normal, extended
	3	120	Normal
	4	240	Normal

Only when μ=2, namely, in the case of a 60-kHz subcarrier spacing, is the extended CP supported, and only the normal CP is supported in the case of other subcarrier spacings. For the normal CP, each slot includes 14 OFDM symbols; for the extended CP, each slot includes 12 OFDM symbols. For μ=0, namely, a 15-kHz subcarrier spacing, one slot=1 ms; for μ=1, namely, a 30-kHz subcarrier spacing, one slot=0.5 ms; for μ=2, namely, a 60-kHz subcarrier spacing, one slot=0.25 ms, and so on.

NR and LTE have the same definition for a subframe, which denotes 1 ms. For a subcarrier spacing configuration μ, a slot index in one subframe (1 ms) may be expressed as n_s^μ, and ranges from 0 to N_slot^subframe,μ−1. A slot index in one system frame (having a duration of 10 ms) may be expressed as n_s,f^μ, and ranges from 0 to N_slot^frame,μ−1. Definitions of N_slot^subframe,μ and N_slot^frame,μ for different subcarrier spacings μ are shown in the tables below.

TABLE 4.3.2-1
the number of symbols included in each slot, the number
of slots included in each system frame, and the number
of slots included in each subframe for the normal CP
	μ	Nsymbslot	Nslotframe, μ	Nslotsubframe, μ
	0	14	10	1
	1	14	20	2
	2	14	40	4
	3	14	80	8
	4	14	160	16

TABLE 4.3.2-2
the number of symbols included in each slot, the number of
slots included in each system frame, and the number of slots
included in each subframe for the extended CP (60 kHz)
	μ	Nsymbslot	Nslotframe, μ	Nslotsubframe, μ
	2	12	40	4

On an NR carrier, a system frame (or simply referred to as frame) number (SFN) ranges from 0 to 1023. The concept of a direct system frame number DFN is introduced to sidelink, and the number likewise ranges from 0 to 1023. The above description of the relationship between the system frame and the numerology can also be applied to a direct system frame. For example, the duration of one direct system frame is likewise equal to 10 ms; for a 15 kHz subcarrier spacing, one direct system frame includes 10 slots, and so on. The DFN is applied to timing on a sidelink carrier.

Parameter Sets in LTE (Including LTE V2X) and Slots and Subframes in LTE (Including LTE V2X)

The LTE only supports a 15 kHz subcarrier spacing. Both the extended CP and the normal CP are supported in the LTE. The subframe has a duration of 1 ms and includes two slots. Each slot has a duration of 0.5 ms.

For a normal CP, each subframe includes 14 OFDM symbols, and each slot in the subframe includes 7 OFDM symbols; for an extended CP, each subframe includes 12 OFDM symbols, and each slot in the subframe includes 6 OFDM symbols.

Resource Block (RB) and Resource Element (RE)

The resource block (RB) is defined in the frequency domain as N_sc^RB=12 consecutive subcarriers. For example, for a 15 kHz subcarrier spacing, the RB is 180 kHz in the frequency domain. For a 15 kHz×2^μ subcarrier spacing, the resource element (RE) represents one subcarrier in the frequency domain and one OFDM symbol in the time domain.

Sidelink Communication Scenario

• • 1) Out-of-coverage sidelink communication: both of two UEs performing sidelink communication are out of network coverage (for example, the UE cannot detect any cell that meets a “cell selection criterion” on a frequency at which sidelink communication needs to be performed, and that means the UE is out of network coverage).
  • 2) In-coverage sidelink communication: both of two UEs performing sidelink communication are in network coverage (for example, the UE detects at least one cell that meets a “cell selection criterion” on a frequency at which sidelink communication needs to be performed, and that means the UE is in network coverage).
  • 3) Partial-coverage sidelink communication: one of two UEs performing sidelink communication is out of network coverage, and the other is in network coverage.

From the perspective of the UE side, the UE only has two scenarios, out-of-coverage and in-coverage. Partial-coverage is described from the perspective of sidelink communication.

Basic Procedure of LTE V2X (Sidelink) Communication

FIG. 1 is a schematic diagram showing sidelink communication of LTE V2X UE. First, UE1 transmits to UE2 sidelink control information (SCI format 1), which is carried by a physical layer channel PSCCH. SCI format 1 includes scheduling information of a PSSCH, such as frequency domain resources and the like of the PSSCH. Secondly, UE1 transmits to UE2 sidelink data, which is carried by the physical layer channel PSSCH. The PSCCH and the corresponding PSSCH are frequency division multiplexed, that is, the PSCCH and the corresponding PSSCH are located in the same subframe in the time domain but are located on different RBs in the frequency domain. In LTE V2X, one transport block (T_B) may include only one initial transmission, or include one initial transmission and one blind retransmission (indicating a retransmission not based on HARQ feedback).

Specific design methods of the PSCCH and the PSSCH are as follows:

• • 1) The PSCCH occupies one subframe in the time domain and two consecutive RBs in the frequency domain. Initialization of a scrambling sequence uses a predefined value of 510. The PSCCH may carry SCI format 1, wherein the SCI format 1 at least includes frequency domain resource information of the PSSCH. For example, for a frequency domain resource indication field, SCI format 1 indicates a starting sub-channel number and the number of consecutive sub-channels of the PSSCH corresponding to the PSCCH.
  • 2) The PSSCH occupies one subframe in the time domain, and the PSSCH and the corresponding PSCCH are frequency division multiplexed (FDM). The PSSCH occupies one or a plurality of consecutive sub-channels in the frequency domain. The sub-channel represents n_subCHsize consecutive RBs in the frequency domain, n_subCHsize is configured by an RRC parameter, and a starting sub-channel and the number of consecutive sub-channels are indicated by a frequency domain resource indication field of the SCI format 1.

LTE V2X Resource Allocation Modes: Transmission Mode 3/Transmission Mode 4

FIG. 2 shows two LTE V2X resource allocation modes, which are referred to as base station scheduling-based resource allocation (transmission mode 3) and UE sensing-based resource allocation (transmission mode 4), respectively. In NR sidelink, transmission mode 3 in LTE V2X corresponds to transmission mode 1 in NR V2X, and is a base station scheduling-based transmission mode, and transmission mode 4 in LTE V2X corresponds to transmission mode 2 in NR V2X, and is a UE sensing-based transmission mode. In LTE V2X, when there is eNB network coverage, a base station can configure, through UE-level dedicated RRC signaling SL-V2X-ConfigDedicated, a resource allocation mode of UE, which may also be referred to as a transmission mode of the UE, and is specifically as follows:

• • 1) Base station scheduling-based resource allocation mode (transmission mode 3): the base station scheduling-based resource allocation mode means that frequency domain resources used in sidelink communication are scheduled by the base station. Transmission mode 3 includes two scheduling modes, which are dynamic scheduling and semi-persistent scheduling (SPS), respectively. For dynamic scheduling, a UL grant (DCI format 5A) includes the frequency domain resources of the PSSCH, and a CRC of a PDCCH or an EPDCCH carrying the DCI format 5A is scrambled by an SL-V-RNTI. For SPS, the base station configures one or a plurality of (at most 8) configured grants through IE: SPS-ConfigSL-r14, and each configured grant includes a grant index and a resource period of the grant. The UL grant (DCI format 5A) includes the frequency domain resource of the PSSCH, indication information (3 bits) of the grant index, and indication information of SPS activation or release (or deactivation). The CRC of the PDCCH or the EPDCCH carrying the DCI format 5A is scrambled by an SL-SPS-V-RNTI.

Specifically, when RRC signaling SL-V2X-ConfigDedicated is set to scheduled-r14, same indicates that the UE is configured in the base station scheduling-based transmission mode. The base station configures the SL-V-RNTI or the SL-SPS-V-RNTI by means of RRC signaling, and transmits the UL grant to the UE by means of the PDCCH or the EPDCCH (DCI format 5A, the CRC is scrambled by the SL-V-RNTI or the SL-SPS-V-RNTI). The UL grant includes at least scheduling information of the PSSCH frequency domain resource in sidelink communication. When the UE successfully detects the PDCCH or the EPDCCH scrambled by the SL-V-RNTI or the SL-SPS-V-RNTI, the UE uses a PSSCH frequency domain resource indication field in the UL grant (DCI format 5A) as PSSCH frequency domain resource indication information in a PSCCH (SCI format 1), and transmits the PSCCH (SCI format 1) and a corresponding PSSCH.

For SPS in transmission mode 3, the UE receives, on a downlink subframe n, the DCI format 5A scrambled by the SL-SPS-V-RNTI. If the DCI format 5A includes the indication information of SPS activation, then the UE determines frequency domain resources of the PSSCH according to the indication information in the DCI format 5A, and determines time domain resources of the PSSCH (transmission subframes of the PSSCH) according to information such as the subframe n and the like.

• • 2) UE sensing-based resource allocation mode (transmission mode 4): the UE sensing-based resource allocation mode means that resources used in sidelink communication are based on a procedure of sensing, by the UE, a candidate available resource set. When the RRC signaling SL-V2X-ConfigDedicated is set to ue-Selected-r14, it indicates that the UE is configured in the UE sensing-based transmission mode. In the UE sensing-based transmission mode, the base station configures an available transmission resource pool, and the UE determines a PSSCH sidelink transmission resource in the transmission resource pool according to a certain rule (for a detailed description of the procedure, see the LTE V2X UE sensing procedure section), and transmits a PSCCH (SCI format 1) and a corresponding PSSCH.

Sidelink Resource Pool

In sidelink, resources transmitted and received by UE all belong to resource pools. For example, for a base station scheduling-based transmission mode in sidelink, the base station schedules transmission resources for sidelink UE in a resource pool; alternatively, for a UE sensing-based transmission mode in sidelink, the UE determines a transmission resource in a resource pool. In the specification of the present patent, a slot in a sidelink resource pool is marked as t_i′^SL (i=0, 1, . . . , T_max′−1), wherein T′_max represents the number of slots within 10240 ms (SFN/DFN 0 to SFN/DFN 1023) belonging to the resource pool.

Resource Allocation Mode Based on (Partial) Sensing

For a resource allocation mode based on (partial) sensing, sidelink user equipment selects a candidate resource within one time window, determines, according to a reserved resource indicated by a PSCCH transmitted by other user equipment in a monitoring slot, candidate resources overlapping with the reserved resource, and excludes the foregoing candidate resources overlapping with the reserved resource. The physical layer reports, to the MAC layer, a set of candidate resources that are not excluded, and the MAC layer selects a transmission resource for the PSSCH/PSCCH. A set of transmission resources selected by the MAC layer is referred to as a selected sidelink grant.

Resource Selection Window [n+T1, n+T2]

In a resource allocation mode based on sensing (or, partial sensing), a higher layer requests or triggers, in a slot n, the physical layer to determine a resource for PSSCH/PSCCH transmission (to perform sensing or partial sensing). The resource selection window is defined as [n+T1, n+T2]. That is, user equipment selects a transmission resource within the foregoing window. T1 satisfies the condition 0≤T1≤T_proc,1^SL, and the selection of T1 is up to user equipment implementation. RRC configuration information includes a resource selection window configuration list sl-SelectionWindowList, and an element on the list and corresponding to a given priority prio_TX (the priority of transmitting the PSSCH) is represented by T_2min. If T_2min is less than a remaining packet delay budget (PDB), T2 satisfies the condition T_2min≤T2≤remaining PDB, and the selection of T2 is up to user equipment implementation; otherwise, T2 is set to the remaining PDB. T_proc,1^SL is defined as follows (μ_SL represents a sidelink subcarrier spacing parameter, that is, the subcarrier spacing is 2^μSL×15 kHz):

TABLE 8.1.4-2
Values of Tproc, 1SL
μSL Tproc, 1SL [slots]
0   3
1   5
2   9
3   17

TABLE 8.1.4-1
Values of Tproc, 0SL
μSL Tproc, 1SL [slots]
0   1
1   1
2   2
3   4

Sidelink Discontinuous Reception (SL DRX) and Retransmission Timer

For SL DRX, sidelink user equipment monitors the PSCCH within an active time. User equipment does not need to monitor the PSCCH within an in-active time.

In SL DRX, user equipment determines whether a current time is an active time or an in-active time by means of some timers (running or expiring). For a retransmission timer, it is indicated that when the timer is running, the user equipment considers that peer user equipment may transmit a PSCCH to schedule a retransmission, so that when the retransmission timer is running (does not expire), an active time is indicated. In the description of the present invention, expiration of a timer indicates that a running time of the timer exceeds the duration of the timer, i.e., referred to as that the timer expires.

Hereinafter, specific examples and embodiments related to the present invention are described in detail. In addition, as described above, the examples and embodiments described in the present disclosure are illustrative descriptions for facilitating understanding of the present invention, rather than limiting the present invention.

Embodiment 1

FIG. 3 is a schematic diagram showing a basic procedure of a method performed by user equipment according to Embodiment 1 of the present invention.

The method performed by user equipment according to Embodiment 1 of the present invention is described in detail below in conjunction with the basic procedure diagram shown in FIG. 3.

As shown in FIG. 3, in Embodiment 1 of the present invention, the steps performed by user equipment include the following:

• • In step S101, requesting (or triggering), by a higher layer (or an upper layer), sidelink user equipment (the physical layer) to determine a resource subset for PSSCH/PSCCH transmission.

The higher layer selects a sidelink resource for the PSSCH/PSCCH transmission in the resource subset.

Optionally, a resource allocation mode of the user equipment is a resource allocation mode based on partial sensing.

Optionally, the higher layer requests, in a slot n, the sidelink user equipment to determine the resource subset.

• • In step S102, determining, by the sidelink user equipment, a set of candidate slots.

Optionally, a means used by the user equipment to determine the set of candidate slots is up to user equipment (UE) implementation.

The first slot in the time domain in the set of candidate slots is represented by t_yo′^SL. n+T_B=t_yo′^SL−T_proc,1^SL−T_proc,0^SL, or n+T_B=t_yo′^SL−T_proc,1^SL, or n+T_B=t_yo′^SL−T_proc,0^SL.

In step S103, determining, by the sidelink user equipment, the number Q of sidelink control information (SCI) assumed (to be) received that are identical to SCI received in a slot t_m′^SL.

A resource reservation period indicated by a resource reservation period indication field in the SCI received by the user equipment in the slot t_m′^SL is P_{rsvp_RX}.

Optionally, (if T_B≥T1, or if T_B>T1), if and only if the resource reservation period indication field is present in the SCI, the user equipment assumes that SCI identical to the SCI is (to be) received in a slot

$t_{m+q\times P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }}^{{ }_{}\prime \mathrm{SL}};$

wherein q=1, 2, . . . , Q.

$P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }=\lceil \frac{T_{\max }^{{ }_{}\prime }}{10240\mathrm{ms}}\times P_{\mathrm{rsvp}\_\mathrm{RX}}\rceil ,$

T′_max representing the number of slots within 10240 ms (SFN/DFN 0 to SFN/DFN 1023) belonging to the resource pool. Optionally, if P_{rsvp_RX}<T2−T_B and n′−m≤P′_{rsvp_RX}, then

$Q=\lceil \frac{T2-T_B}{P_{\mathrm{rsvp}\_\mathrm{RX}}}\rceil ,$

otherwise, Q=1. If a slot (n+T_B) is a slot in the resource pool, then t_n′′^SL=n+T_B, otherwise, t_n′′^SL represents the first slot after the slot (n+T_B) in the resource pool.

Optionally, (if T_B≤T1, or if T_B<T1), if and only if the resource reservation period indication field is present in the SCI, the user equipment assumes that SCI identical to the SCI is (to be) received in a slot

$t_{m+q\times P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }}^{{ }_{}\prime \mathrm{SL}};$

wherein q=1, 2, . . . , Q.

$P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }=\lceil \frac{T_{\max }^{{ }_{}\prime }}{10240\mathrm{ms}}\times P_{\mathrm{rsvp}\_\mathrm{RX}}\rceil ,$

T′max representing the number of slots within 10240 ms (SFN/DFN 0 to SFN/DFN 1023) belonging to the resource pool. Optionally, if P_{rsvp_RX}<T2 and n′−m≤P′_{rsvp_RX}, then

$Q=\lceil \frac{T2}{P_{\mathrm{rsvp}\_\mathrm{RX}}}\rceil ,$

otherwise, Q=1. If the slot n is a slot in the resource pool, then t_n′′^SL=n, otherwise, t_n′′^SL represents the first slot after the slot n in the resource pool.

Embodiment 2

FIG. 3 is a schematic diagram showing a basic procedure of a method performed by user equipment according to Embodiment 2 of the present invention.

The method performed by user equipment according to Embodiment 2 of the present invention is described in detail below in conjunction with the basic procedure diagram shown in FIG. 3.

As shown in FIG. 3, in Embodiment 2 of the present invention, steps performed by the user equipment include the following:

• • In step S101, requesting (or triggering), by a higher layer (or an upper layer), sidelink user equipment (the physical layer) to determine a resource subset for PSSCH/PSCCH transmission.

The higher layer selects a sidelink resource for the PSSCH/PSCCH transmission in the resource subset.

Optionally, a resource allocation mode of the user equipment is a resource allocation mode based on partial sensing.

Optionally, the higher layer requests, in a slot n, the sidelink user equipment to determine the resource subset.

A slot n+T_B represents the (first) slot located after a slot n (or a slot n+1) and separated therefrom by 31 (or 32) slots included in a resource pool.

• • In step S102, determining, by the sidelink user equipment, a set of candidate slots.

Optionally, a means used by the user equipment to determine the set of candidate slots is up to user equipment (UE) implementation.

• • In step S103, determining, by the sidelink user equipment, the number Q of sidelink control information (SCI) assumed (to be) received that are identical to SCI received in a slot t_m′^SL.

A resource reservation period indicated by a resource reservation period indication field in the SCI received by the user equipment in the slot t_m′^SL is P_{rsvp_RX}.

Optionally, if and only if the resource reservation period indication field is present in the SCI, the user equipment assumes that SCI identical to the SCI is (to be) received in a slot

$t_{m+q\times P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }}^{{ }_{}\prime \mathrm{SL}};$

wherein q=1, 2, . . . , Q.

$P_{\mathrm{rsvp}\_\mathrm{RX}}^{{ }_{}\prime }=\lceil \frac{T_{\max }^{{ }_{}\prime }}{10240\mathrm{ms}}\times P_{\mathrm{rsvp}\_\mathrm{RX}}\rceil ,$

T′max representing the number of slots within 10240 ms (SFN/DFN 0 to SFN/DFN 1023) belonging to the resource pool. Optionally, if P_{rsvp_RX}<T2−T_B and n′−m≤P′_{rsvp_RX}, then

$Q=\lceil \frac{T2-T_B}{P_{\mathrm{rsvp}\_\mathrm{RX}}}\rceil ,$

otherwise, Q=1. If a slot (n+T_B) is a slot in the resource pool, then t_n′′^SL=n+T_B, otherwise, t_n′′^SL represents the first slot after the slot (n+T_B) in the resource pool.

Embodiment 3

FIG. 4 is a schematic diagram showing a basic procedure of a method performed by user equipment according to Embodiment 3 of the present invention.

The method performed by user equipment according to Embodiment 3 of the present invention is described in detail below in conjunction with the basic procedure diagram shown in FIG. 4.

As shown in FIG. 4, in Embodiment 3 of the present invention, the steps performed by the user equipment include:

In step S201, indicating, by the physical layer of sidelink user equipment to the MAC layer, that one or a plurality of sidelink resources in a selected sidelink grant are pre-empted.

Optionally, a prior sidelink control information (SCI) indicates the one or the plurality of sidelink resources.

Optionally, the physical layer indicates a resource set to the MAC layer.

In step S202, performing, by the user equipment, resource reselection for the one or the plurality of sidelink resources.

Optionally, the user equipment removes the one or the plurality of sidelink resources from the selected sidelink grant.

Optionally, for a resource r′_i in the one or the plurality of (or, in the time domain, the first) sidelink resources, the user equipment randomly selects a sidelink time-frequency resource r′_ii from the resource set. r′_ii at least satisfies the following conditions: the time-frequency resource r′_ii is after the resource r′_i (or, not before the resource r′_i), and/or, the time interval between the time-frequency resource r′_ii and the resource r′_i does not exceed the duration of a retransmission timer.

FIG. 5 shows a block diagram of user equipment (UE) according to the present invention. As shown in FIG. 5, the user equipment (UE) 80 includes a processor 801 and a memory 802. The processor 801 may include, for example, a microprocessor, a microcontroller, an embedded processor, and the like. The memory 802 may include, for example, a volatile memory (such as a random access memory (RAM)), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memories. The memory 802 stores program instructions. The instructions, when run by the processor 801, can implement the above method performed by user equipment as described in detail in the present invention.

The method and related equipment according to the present invention have been described above in combination with preferred embodiments. It should be understood by those skilled in the art that the method shown above is only exemplary, and the above embodiments can be combined with one another as long as no contradiction arises. The method of the present invention is not limited to the steps or sequences illustrated above. The network node and user equipment illustrated above may include more modules. For example, the network node and user equipment may further include modules that can be developed or will be developed in the future to be applied to a base station, an MME, or UE, and the like. Various identifiers shown above are only exemplary, and are not meant for limiting the present invention. The present invention is not limited to specific information elements serving as examples of these identifiers. A person skilled in the art could make various alterations and modifications according to the teachings of the illustrated embodiments.

It should be understood that the above-described embodiments of the present invention may be implemented by software, hardware, or a combination of software and hardware. For example, various components of the base station and user equipment in the above embodiments can be implemented by multiple devices, and these devices include, but are not limited to: an analog circuit device, a digital circuit device, a digital signal processing (DSP) circuit, a programmable processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), and the like.

In the present application, the “base station” may refer to a mobile communication data and control exchange center having large transmission power and a wide coverage area, including functions such as resource allocation and scheduling and data reception and transmission. “User equipment” may refer to a user mobile terminal, for example, including terminal devices that can communicate with a base station or a micro base station wirelessly, such as a mobile phone, a laptop computer, and the like.

In addition, the embodiments of the present invention disclosed herein may be implemented on a computer program product. More specifically, the computer program product is a product provided with a computer-readable medium having computer program logic encoded thereon. When executed on a computing device, the computer program logic provides related operations to implement the above 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 (the method) described in the embodiments of the present invention. Such setting of the present invention is typically provided as software, codes and/or other data structures provided or encoded on the computer-readable medium, e.g., an optical medium (e.g., compact disc read-only memory (CD-ROM)), a flexible disk or a hard disk and the like, or other media such as firmware or micro codes on one or more read-only memory (ROM) or random access memory (RAM) or programmable read-only memory (PROM) chips, or a downloadable software image, a shared database and the like in one or more modules. Software or firmware or such configuration may be installed on a computing device such that one or more processors in the computing device perform the technical solutions described in the embodiments of the present invention.

In addition, each functional module or each feature of the base station device and the terminal device used in each of the above embodiments may be implemented or executed by a circuit, which is usually one or more integrated circuits. Circuits designed to execute various functions described in this description 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 gates or transistor logic, or discrete hardware components, or any combination of the above. The general purpose processor may be a microprocessor, or the processor may be an existing processor, a controller, a microcontroller, or a state machine. The aforementioned general purpose processor or each circuit may be configured by a digital circuit or may be configured by a logic circuit. Furthermore, when advanced technology capable of replacing current integrated circuits emerges due to advances in semiconductor technology, the present invention can also use integrated circuits obtained using this advanced technology.

While the present invention has been illustrated in combination with the preferred embodiments of the present invention, it will be understood by those skilled in the art that various modifications, substitutions, and alterations may be made to the present invention without departing from the spirit and scope of the present invention. Therefore, the present invention should not be limited by the above-described embodiments, but should be defined by the appended claims and their equivalents.

Claims

1-7. (canceled)

8. A User equipment, comprising: a processor; anda memory, wherein the memory stores instructions that cause the processor to:remove a first resource from a selected sidelink grant if the first resource is indicated for pre-emption by a physical layer; andre-select a second resource from a resource set indicated by the physical layer, wherein the second resource is later than the first resource.

9. A control method in a User Equipment comprising: removing a first resource from a selected sidelink grant if the first resource is indicated for pre-emption by a physical layer; andre-selecting a second resource from a resource set indicated by the physical layer, wherein the second resource is later than the first resource.