Method and user equipment for sidelink packet switching operation

Abstract

A method performed by a UE is provided. The method comprises: receiving at least one SL-DRX configuration and a plurality of SL resource pool configurations to be configured on the first UE; when an SL-DRX operation is performed based on the at least one SL-DRX configuration, performing partial sensing based on at least one SL resource pool configuration among the plurality of SL resource pool configurations, and performing SL-CBR measurements associated with each of the at least one SL resource pool.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 62 / 964,012, entitled “Sidelink Discontinuous Reception (SL-DRX) Mechanisms”, filed on January 21, 2020 (hereinafter “the '012 Provisional”). The disclosure of the '012 Provisional is hereby fully incorporated by reference into this disclosure for all purposes. Technical Field

[0003] The present disclosure relates generally to wireless communications, and more particularly to methods and user equipment for sidelink (SL) packet switching operations. Background Art

[0004] With the huge growth in the number of connected devices and the rapid increase in user / network (NW) traffic, various efforts have been made to improve different aspects of wireless communications in next-generation wireless communication systems (such as the fifth generation (5G) New Radio (NR)) by improving data rate, latency, reliability and mobility.

[0005] The 5G NR system is designed to provide flexibility and configurability to optimize NW services and types to adapt to different use cases, such as enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable and low-latency communication (URLLC).

[0006] However, as the demand for radio access continues to increase, there exists a need in the art for improved sidelink (SL) packet switched operations. Summary of the invention

[0007] The present disclosure relates to a method and a user equipment (UE) for sidelink packet switching operation.

[0008] According to a first aspect of the present disclosure, a method for sidelink (SL) packet switching operation performed by a first user equipment (UE) is provided. The method comprises: receiving at least one SL-discontinuous reception (SL-DRX) configuration and a plurality of SL resource pool configurations to be configured on the first UE; when the SL-DRX operation is performed based on the at least one SL-DRX configuration, performing partial sensing based on at least one SL resource pool configuration among the plurality of SL resource pool configurations, and performing SL-channel busy rate (SL-CBR) measurement associated with each of the at least one SL resource pool.

[0009] In one embodiment of the first aspect, the method also includes receiving indication information associated with a first SL resource pool configuration among the multiple SL resource pool configurations, the indication information being used to indicate whether the first UE is capable of performing the partial sensing on the SL resource pool configured by the first SL resource pool configuration during at least one SL-DRX off period.

[0010] According to a second aspect of the present disclosure, a user equipment (UE) for sidelink (SL) packet switching operation in a wireless communication system is provided, the wireless communication system comprising a base station (BS). The UE comprises: one or more non-transitory computer-readable media having computer executable instructions contained thereon; and at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor being configured to execute the computer executable instructions so that the UE: receives at least one SL-discontinuous reception (SL-DRX) configuration and a plurality of SL resource pool configurations to be configured on the first UE; when the SL-DRX operation is performed based on the at least one SL-DRX configuration, performs partial sensing based on at least one SL resource pool configuration of the plurality of SL resource pool configurations, and performs SL-channel busy rate (SL-CBR) measurement associated with each of the at least one SL resource pool.

[0011] In one embodiment of the second aspect, the at least one processor is also configured to execute the computer-executable instructions so that the UE: receives indication information associated with a first SL resource pool configuration among the multiple SL resource pool configurations, and the indication information is used to indicate whether the first UE is able to perform the partial sensing on the SL resource pool configured by the first SL resource pool configuration during at least one SL-DRX off period. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] When combined with Figure 1Aspects of the present disclosure are best understood from the following when read together. Various features are not drawn to scale. The size of various features may be arbitrarily increased or decreased for clarity of discussion.

[0013] Figure 1 An SL operation for UEs to exchange information according to an exemplary embodiment of the present disclosure is shown.

[0014] Figure 2 A V2X platoon scenario according to an exemplary embodiment of the present disclosure is shown.

[0015] Figure 3 A PC5-RRC connection between a pair of UEs according to an exemplary embodiment of the present disclosure is shown.

[0016] Figure 4 A SL-DRX configuration according to an exemplary embodiment of the present disclosure is shown.

[0017] FIG. 5( a ), FIG. 5 ( b ), and FIG. 5 ( c ) illustrate different side link (SL) sensing windows according to different exemplary embodiments of the present disclosure.

[0018] Figure 6 A SL packet exchange process performed by a first UE according to an exemplary embodiment of the present disclosure is shown.

[0019] Figure 7 A block diagram of a node for wireless communication according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0020] The following contains specific information related to exemplary embodiments in the present disclosure. The drawings in the present disclosure and the detailed disclosure attached thereto are only for exemplary embodiments. However, the present disclosure is not limited to these exemplary embodiments. Other variations and embodiments of the present disclosure will occur to those skilled in the art. Unless otherwise stated, the same or corresponding elements in the drawings may be represented by the same or corresponding reference numerals. Moreover, the drawings and diagrams in the present disclosure are generally not drawn to scale and are not intended to correspond to actual relative sizes.

[0021] The following description contains specific information related to the exemplary embodiments in the present disclosure. The drawings in the present disclosure and the detailed disclosure attached thereto are only for exemplary embodiments. However, the present disclosure is not limited to these exemplary embodiments. Other variations and embodiments of the present disclosure will occur to those skilled in the art. Unless otherwise specified, the same or corresponding elements in the drawings may be represented by the same or corresponding reference numerals. Moreover, the drawings and diagrams in the present disclosure are usually not drawn to scale and are not intended to correspond to actual relative sizes.

[0022] For the purpose of consistency and ease of understanding, similar features are identified by reference numerals in the exemplary drawings (but not shown in some examples). However, features in different embodiments may differ in other aspects and should not be narrowly limited to what is shown in the drawings.

[0023] References to "one embodiment," "an embodiment," "an exemplary embodiment," "various embodiments," "some embodiments," "embodiments of the present disclosure," and the like may indicate that the embodiments of the present disclosure described herein may include a particular feature, structure, or characteristic, but not every possible embodiment of the present disclosure necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrases "in one embodiment," "in an exemplary embodiment," or "an embodiment" does not necessarily refer to the same embodiment, although they may refer to the same embodiment. In addition, any phrases like "embodiments" used in conjunction with the "present disclosure" are by no means intended to characterize that all embodiments of the present disclosure must include a particular feature, structure, or characteristic, but rather should be understood to mean that "at least some embodiments of the present disclosure" include the stated particular feature, structure, or characteristic. The term "coupled" is defined as connected, whether directly or indirectly through intermediate components, and is not necessarily limited to physical connections. The term "comprising," when utilized, means "including, but not necessarily limited to," and specifically indicates open inclusion or membership in the combinations, groups, series, and equivalents described herein.

[0024] The term "and / or" in this article is only used to describe the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. "A and / or B and / or C" can mean that at least one of A, B and C exists. In addition, the character " / " used here generally indicates that the previous associated object and the next associated object are in an "or" relationship.

[0025] In addition, for the purpose of non-limiting explanation, specific details such as functional entities, technologies, protocols, standards, etc. are described to provide an understanding of the described technology. In other examples, detailed descriptions of well-known methods, technologies, systems, architectures, etc. are omitted to avoid making the present disclosure unclear with unnecessary details.

[0026] Those skilled in the art will immediately recognize that any NW function or algorithm of the present disclosure can be implemented by hardware, software, or a combination of software and hardware. The described functions may correspond to modules, which may be software, hardware, firmware, or any combination thereof. Software implementations may include computer executable instructions stored on a computer-readable medium such as a memory or other type of storage device. For example, one or more microprocessors or general-purpose computers with communication processing capabilities may be programmed using corresponding executable instructions and perform the described NW functions or algorithms. These microprocessors or general-purpose computers may be formed by application specific integrated circuits (ASIC: Applications Specific Integrated Circuitry), programmable logic arrays, and / or using one or more digital signal processors (DSP: Digital Signal Processor). Although several exemplary embodiments described in the present disclosure are for software installed and executed on computer hardware, alternative exemplary embodiments implemented as firmware or hardware or a combination of hardware and software are also within the scope of the present disclosure.

[0027] Computer-readable media include, but are not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, compact disc read-only memory (CD-ROM), cassettes, magnetic tapes, disk storage, or any other equivalent medium capable of storing computer-readable instructions.

[0028] The radio communication NW architecture (e.g., Long Term Evolution (LTE) system, LTE-Advanced (LTE-A) system, LTE-Advanced Pro system) generally includes at least one base station (BS), at least one user equipment (UE), and one or more optional NW elements that provide a connection to the NW. The UE communicates with the NW (e.g., core NW (CN: Core Network), evolved packet core (EPC: Evolved Packet Core) NW, evolved universal terrestrial radio access NW (E-UTRAN: Evolved Universal Terrestrial Radio Access Network), next generation core (NGC: Next-Generation Core), 5G core network (5GC: 5G Core Network) or the Internet) through the radio access NW (RAN: Radio Access Network) established by the BS.

[0029] It should be noted that in the present disclosure, UE may include but is not limited to a mobile station, a mobile terminal or device, a user communication radio terminal. For example, UE may be a portable radio device, which includes but is not limited to a mobile phone, a tablet computer, a wearable device, a sensor or a personal digital assistant (PDA) with wireless communication capabilities. UE is configured to receive signals over an air interface and transmit signals to one or more cells in the RAN.

[0030] BS may include, but is not limited to, Node B (NB) in Universal Mobile Telecommunication System (UMTS), evolved Node B (eNB) in LTE-A, Radio Network Controller (RNC) in UMTS, Base Station Controller (BSC) in Global System for Mobile Communication (GSM) / GSM EDGE Radio Access NW (GERAN), Next Generation-eNB (ng-eNB) in E-UTRABS connected to 5GC, Next Generation Node B (gNB) in 5G Access NW (5G-AN), and any other device capable of controlling radio communications and managing radio resources within a cell. BS can be connected to the radio interface to NW to serve one or more UEs.

[0031] The BS may be configured to provide communication services according to at least one of the following radio access technologies (RATs): Worldwide Interoperability for Microwave Access (WiMAX), GSM (commonly referred to as 2G), GERAN, General Packet Radio Service (GPRS), UMTS based on basic wideband-Code Division Multiple Access (W-CDMA) (commonly referred to as 3G), High-Speed ​​Packet Access (HSPA), LTE, LTE-A, evolved LTE (eLTE), New Radio (NR, commonly referred to as 5G) and / or LTE-A Pro. However, the scope of the present disclosure should not be limited to the above protocols.

[0032] The BS is operable to provide radio coverage to a specific geographical area using multiple cells included in the RAN. The BS supports the operation of cells. Each cell is operable to provide services to at least one UE within its radio coverage. More specifically, each cell (commonly referred to as a serving cell) can provide services to serve one or more UEs within its radio coverage (for example, each cell schedules downlink (DL: Downlink) and optional UL resources to at least one UE within its radio coverage for downlink and optional uplink packet transmission). The BS can communicate with one or more UEs in a radio communication system through multiple cells. The cell can allocate sidelink (SL: Sidelink) resources for supporting proximity services (ProSe: Proximity service). Each cell may have a coverage area that overlaps with other cells. In the case of multi-RAT dual connectivity (MR-DC), the main cell of a master cell group (MCG: Master Cell Group) or a secondary cell group (SCG: Secondary Cell Group) can be referred to as a special cell (SpCell: Special Cell). The primary cell (PCell: Primary Cell) can refer to the SpCell of the MCG. PSCell may refer to the SpCell of the SCG. MCG refers to a service cell group associated with a master node (MN), including SpCell and optionally one or more secondary cells (SCell). SCG refers to a service cell group associated with a secondary node (SN), including SpCell and optionally one or more Scells. Please note that in some embodiments, the UE may not have a (LTE / NR) radio resource control (RRC) connection with the concerned service cell of the associated service (in other words, the UE may not have UE-specific RRC signaling exchanged with the serving cell). Instead, the UE may only listen to DL synchronization signals (e.g., DL synchronization burst sets) and / or broadcast system information (SI: System Information) related to the concerned service from such a serving cell. In addition, the UE may have at least one serving cell on one or more target SL frequency carriers for the associated service. In some additional embodiments, the UE may regard the RAN configured with one or more service cells as the serving RAN.

[0033] As previously disclosed, the frame structure for NR supports flexible configuration to accommodate various next-generation (e.g., 5G) communication requirements, such as eMBB, mMTC, and URLLC, while meeting high reliability, high data rate, and low latency requirements. Orthogonal frequency division multiplexing (OFDM) technology as agreed in the Third Generation Partnership Project (3GPP) can be used as a baseline for the NR waveform. Scalable OFDM parameter sets, such as adaptive subcarrier spacing, channel bandwidth, and cyclic prefix (CP) can also be used. In addition, two coding schemes are considered for NR: (1) Low Density Parity Check Code (LDPC) code and (2) polar code. Coding scheme adaptation can be configured based on channel conditions and / or service applications.

[0034] In addition, it is also considered that in the transmission time interval of a single NR frame, at least DL transmission data, protection period and UL transmission data should be included, wherein the various parts of DL transmission data, protection period and UL transmission data should also be configurable, for example, dynamically configured based on the NW of NR. In addition, SL resources can also be provided in the NR frame to support ProSe services.

[0035] General description of DRX operation

[0036] In some embodiments, the UE may be configured with a DRX function that controls the UE's physical downlink control channel (PDCCH) monitoring activity. When in RRC_CONNECTED, when DRX is configured, the UE may not have to continuously monitor one or more PDCCHs. In some embodiments, the characteristics of DRX may be as follows:

[0037] On-duration: This can be the duration that the UE waits to receive PDCCH after waking up. If the UE successfully decodes the PDCCH, the UE can stay awake and (re)start the deactivation timer;

[0038] inactivity-timer: This may be the duration that the UE waits for a successful decoding of the PDCCH starting from the last successful decoding of the PDCCH, sending the UE back to sleep if the decoding fails. The UE may restart the deactivation timer after a single successful decoding of the PDCCH for the first transmission only (i.e. not for retransmissions);

[0039] retransmission-timer: This can be the duration until a retransmission is expected (e.g., Hybrid Automatic Repeat Request, HARQ);

[0040] cycle: this may specify the periodic repetition of the on-duration followed by a possible deactivation period;

[0041] Active-Time: This may be the total duration that the UE monitors the PDCCH. This may include the "on-duration" of the DRX cycle, the time that the UE is performing continuous reception when the deactivation timer has not expired, and the time that the UE is performing continuous reception when waiting for a retransmission opportunity.

[0042] In some implementations, more detailed UE behaviors are introduced below. The medium access control (MAC) entity can be configured by the RRC layer / entity with DRX function, which controls the UE's PDCCH monitoring activity for the cell radio network temporary identifier (C-RNTI: Cell-Radio Network Temporary Identifier), configured scheduling-radio network temporary identifier (CS-RNTI: ConfiguredScheduling-Radio Network Temporary Identifier), interruption-radio network temporary identifier (INT-RNTI: Interruption-Radio Network Temporary Identifier), time slot format indication-radio network temporary identifier (SFI-RNTI: Slot Format Indication-Radio Network Temporary Identifier), semi-persistent channel state information-radio network temporary identifier (SP-CSI-RNTI: Semi-Persistent-Channel State Information-Radio Network Temporary Identifier), transmission power control-physical uplink control channel-radio network temporary identifier (TPC-PUCCH-RNTI: TransmitPower Control-Physical Uplink Control Channel-Radio Network Temporary Identifier), Transmit Power Control-Physical Uplink Shared Channel-Radio Network Temporary Identifier (TPC-PUSCH-RNTI: Transmit Power Control-Physical Uplink Shared Channel-Radio Network Temporary Identifier), Modulation Coding Scheme Cell-RNTI (MCS-C-RNTI: Modulation Coding Scheme Cell-RNTI),Random Access-RNTI (RA-RNTI: Random Access-RNTI), Paging-RNTI (P-RNTI: Paging-RNTI), System Information-RNTI (SI-RNTI: System Information-RNTI), Sidelink-RNTI (sl-RNTI: Sidelink-RNTI), Sidelink Configured Scheduling-RNTI (sl-CS-RNTI: Sidelink Configured Scheduling-RNTI) and Transmit Power Control-Sounding Reference Symbols-Radio Network Temporary Identifier (TPC-SRS-RNTI: Transmit Power Control-Sounding Reference Symbols-Radio Network Temporary Identifier). When using DRX operation, the MAC entity may also monitor one or more PDCCHs according to the requirements found in the 3GPP Technical Specification (TS: Technical Specification). When in RRC_CONNECTED, if DRX is configured, the MAC entity may use DRX operation to monitor the PDCCH non-continuously for all activated serving cells; otherwise, the MAC entity may monitor the PDCCH. ,

[0043] In some implementations, RRC may control DRX operation by configuring the following parameters:

[0044] drx-onDurationTimer: This can be the duration when the DRX cycle starts;

[0045] drx-SlotOffset: This can be a delay before starting the drx-onDurationTimer;

[0046] drx-InactivityTimer: This may be the duration after the PDCCH indicates a PDCCH opportunity for a new UL or DL ​​transmission for the MAC entity;

[0047] drx-RetransmissionTimerDL (each DL HARQ process except the broadcast process): This may be the maximum duration until a DL retransmission is received;

[0048] drx-RetransmissionTimerUL (per UL HARQ process): This may be the maximum duration until a grant for UL retransmission is received;

[0049] drx-LongCycleStartOffset: This can be the long DRX cycle and drx-StartOffset of the subframe defining the start of the long DRX cycle or the short DRX cycle;

[0050] drx-ShortCycle (optional): This can be a short DRX cycle;

[0051] drx-ShortCycleTimer (optional): This may be the duration that the UE may follow in a short DRX cycle;

[0052] drx-HARQ-RTT-TimerDL (each DL HARQ process except the broadcast process): This may be the minimum duration before a DL allocation that the MAC entity expects for HARQ retransmissions;

[0053] drx-HARQ-RTT-TimerUL (per ULHARQ process): This can be MAC

[0054] The minimum duration before an entity expects a UL HARQ retransmission grant.

[0055] In some embodiments, when a DRX cycle is configured, the (SL-DRX) active time may include the following times:

[0056] drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL or ra-ContentionResolutionTimer (as described in 3GPP TS 38 series specifications) is running; or

[0057] A Scheduling Request (SR) is sent on the PUCCH and is pending (as described in the 3GPP TS 38 series of specifications); or

[0058] • After successfully receiving a random access response to a random access preamble that was not selected by the MAC entity in a contention based random access preamble (as described in 3GPP TS 38 series of specifications), a PDCCH indicating a new transmission of the C-RNTI addressed to the MAC entity has not been received.

[0059] In some implementations, when DRX is configured, the MAC entity may:

[0060] 1> If a MAC PDU is received in a configured downlink allocation:

[0061] 2> After the corresponding transmission carrying DL HARQ feedback ends, start the drx-HARQ-RTT-TimerDL for the corresponding HARQ process in the first symbol;

[0062] 2> Stop the drx-RetransmissionTimerDL for the corresponding HARQ process.

[0063] 1> If the MAC PDU is transmitted in a configured uplink grant:

[0064] 2> After the first repetition of the corresponding PUSCH transmission ends, start the drx-HARQ-RTT-TimerUL for the corresponding HARQ process in the first symbol;

[0065] 2> Stop the drx-RetransmissionTimerUL for the corresponding HARQ process.

[0066] 1> If drx-HARQ-RTT-TimerDL expires:

[0067] 2> If the data of the corresponding HARQ process is not successfully decoded:

[0068] 3>After the drx-HARQ-RTT-TimerDL expires, the drx-RetransmissionTimerDL for the corresponding HARQ process is started in the first symbol.

[0069] 1> If drx-HARQ-RTT-TimerUL expires:

[0070] 2> After the drx-HARQ-RTT-TimerUL expires, the drx-RetransmissionTimerUL for the corresponding HARQ process is started in the first symbol.

[0071] 1> If a DRX command MAC CE or a long DRX command MAC CE is received:

[0072] 2>Stop drx-onDurationTimer;

[0073] 2>Stop drx-InactivityTimer.

[0074] 1> If the drx-InactivityTimer expires or a DRX command MAC CE is received:

[0075] 2> If the short DRX cycle is configured as:

[0076] 3> After the drx-InactivityTimer expires or after the DRX command MAC CE reception is completed in the first symbol, start or restart the drx-ShortCycleTimer in the first symbol;

[0077] 3> Use short DRX cycle.

[0078] 2> Otherwise:

[0079] 3> Use a long DRX cycle.

[0080] 1> If drx-ShortCycleTimer expires:

[0081] 2> Use a long DRX cycle.

[0082] 1> If a long DRX command MAC CE is received:

[0083] 2>Stop drx-ShortCycleTimer;

[0084] 2> Use a long DRX cycle.

[0085] 1> If a short DRX cycle is used, and [(SFN×10)+subframe number] modulo(drx-ShortCycle)=(drx-StartOffset) modulo(drx-ShortCycle); or

[0086] 1> If a long DRX cycle is used, and [(SFN×10)+subframe number] modulo(drx-LongCycle)=drx-StartOffset:

[0087] 2> Start drx-onDurationTimer after drx-SlotOffset from the start of the subframe.

[0088] 1> If the MAC entity is in active time:

[0089] 2> Monitor PDCCH as specified in TS;

[0090] 2> If PDCCH indicates DL transmission:

[0091] 3> After the corresponding transmission carrying DL HARQ feedback ends, start the drx-HARQ-RTT-TimerDL for the corresponding HARQ process in the first symbol;

[0092] 3> Stop the drx-RetransmissionTimerDL for the corresponding HARQ process.

[0093] 2> If PDCCH indicates UL transmission:

[0094] 3> After the first repetition of the corresponding PUSCH transmission ends, start the drx-HARQ-RTT-TimerUL for the corresponding HARQ process in the first symbol;

[0095] 3> Stop the drx-RetransmissionTimerUL for the corresponding HARQ process.

[0096] 2> If PDCCH indicates a new transmission (DL or UL):

[0097] 3> Start or restart drx-InactivityTimer in the first symbol after PDCCH reception ends.

[0098] 1> In the current symbol n, the MAC entity may not be in active time if, when evaluating all DRX active time conditions as specified in this clause, the MAC entity takes into account the Grant / Assignment / DRX Command MAC CE / Long DRX Command MAC CE received 4 ms before symbol n and the SR sent:

[0099] 2> The periodic SRS and semi-persistent SRS defined in TS are not transmitted;

[0100] 2> Do not report CSI on PUCCH and semi-persistent CSI on PUSCH.

[0101] 1> If the CSI mask (csi-Mask) is set by the upper layer:

[0102] 2> In the current symbol n, if drx-onDurationTimer takes into account the Grant / Assignment / DRX Command MAC CE / Long DRX Command MAC CE received up to 4 ms before symbol n when evaluating all DRX Active Time conditions as specified in this clause, drx-onDurationTimer may not run:

[0103] 3> Do not report CSI on PUCCH.

[0104] In some embodiments, regardless of whether the MAC entity is monitoring the PDCCH, the MAC entity may transmit HARQ feedback, aperiodic CSI on the PUSCH, and aperiodic SRS as described in the TS 38 series of specifications when expected. If it is not a full PDCCH opportunity (e.g., the (SL-DRX) active time starts or ends in the middle of a PDCCH opportunity), the MAC entity may not need to monitor the PDCCH.

[0105] DRX Command MAC CE

[0106] In some implementations, the DRX command MAC CE may be identified by a MAC subheader with a logical channel identifier (LCID) as specified in the 3GPP TS 38 series of specifications. Specifically, it may have a fixed size of zero bits.

[0107] Long DRX command MAC CE

[0108] In some embodiments, the Long DRX Command MAC CE may be identified by a MAC subheader with an LCID as described in the 3GPP TS 38 series of specifications. Specifically, it may have a fixed size of zero bits.

[0109] DRX Configuration

[0110] In some implementations, IE DRX-Config may be used to configure DRX related parameters, which may be described as follows:

[0111]

[0112]

[0113]

[0114]

[0115] In addition, the DRX-Config field description may be described as follows:

[0116] drx-HARQ-RTT-TimerDL: This may be the value of the number of symbols of the BWP in which the transport block is received.

[0117] drx-HARQ-RTT-TimerUL: This may be the value of the number of symbols of the BWP in which the transport block is transmitted.

[0118] drx-InactivityTimer: This can be a value in units of integer multiples of 1ms. For example, ms0 corresponds to 0, ms1 corresponds to 1ms, ms2 corresponds to 2ms, and so on.

[0119] drx-LongCycleStartOffset: This can include the drx-

[0120] LongCycle and drx-StartOffset in multiples of 1ms. If drx-

[0121] ShortCycle, the value of drx-LongCycle can be a multiple of the value of drx-ShortCycle.

[0122] drx-onDurationTimer: This can be in multiples of 1 / 32ms (sub-millisecond) or in ms

[0123] For the latter, the value ms1 corresponds to 1ms, the value ms2 corresponds to 2ms, and so on.

[0124] drx-RetransmissionTimerDL: This may be a value that is the number of slot lengths of the BWP in which the transport block is received. For example, a value of sl0 corresponds to 0 slots, sl1 corresponds to 1 slot, sl2 corresponds to 2 slots, and so on.

[0125] drx-RetransmissionTimerUL: This can be the value of the number of slot lengths of the BWP in which the transport block is transmitted. For example, sl0 corresponds to 0 slots, sl1 corresponds to 1 slot, sl2 corresponds to 2 slots, and so on.

[0126] drx-ShortCycleTimer: This can be a value in multiples of drx-ShortCycle. For example, a value of 1 corresponds to drx-ShortCycle, a value of 2 corresponds to 2*drx-ShortCycle, etc.

[0127] drx-ShortCycle: This can be a value in ms. For example, ms1 corresponds to 1ms, ms2 corresponds to 2ms, and so on.

[0128] drx-SlotOffset: This can be a value in multiples of 1 / 32ms. For example, a value of 0 corresponds to 0ms, a value of 1 corresponds to 1 / 32ms, a value of 2 corresponds to 2 / 32ms, and so on.

[0129] V2X services and PC5 interface

[0130] In some embodiments, a vehicle-to-everything (V2X) service may be provided to support information exchange between vehicles. V2X services include at least one of a vehicle-to-infrastructure (V2I) service, a vehicle-to-pedestrian (V2P) service, a vehicle-to-network (V2N) service, and a vehicle-to-vehicle (V2V) service. In the LTE protocol, V2X services may be supported in the air interface through the Uu interface and the PC5 interface. The PC5 interface covers the design in layer 2 and layer 1. The air link interface on the PC5 interface is also referred to as SL in the LTE protocol. Based on 3GPP TS Rel.12, the LTE network supports SL operation. Reference Figure 1 , Figure 1 FIG. 4 shows an SL operation for UE to exchange information according to an exemplary embodiment of the present disclosure. Figure 1 As shown, the UE can directly exchange data and control signaling without the relay of a BS (e.g., an eNB in ​​an LTE network or a gNB in ​​an NR network). For ease of description, each UE in the present disclosure is capable of and authorized to access V2X services through a PC5 interface with neighboring UEs and the RAN.

[0131] In some embodiments, V2X services may be further categorized based on different broadcast types, such as:

[0132] Unicast: Only two UEs in one SL group and the formulation of the SL group can be formulated in the Non-Access-Stratum (NAS) layer.

[0133] Multicast: Group more than two UEs into a SL group to exchange SL packets with all members of the SL group. In one embodiment, the SL group can be formulated in the NAS layer (e.g., V2X application layer or PC5-S protocol) or the AS layer (e.g., SL RRC layer signaling, PC5-RRC signaling).

[0134] Broadcast: There is no restriction on SL groups. A UE can broadcast messages to its neighboring UEs within the SL communication range, and can successfully receive and decode the broadcast messages. In some embodiments, the SL communication range may vary due to Tx power, hardware sensitivity, etc.

[0135] In some embodiments, under the coverage of a RAN (e.g., E-UTRAN or NR-RAN), SL operations (e.g., SL operations configured to support LTE (V2X) sidelink communication, LTE sidelink discovery, LTE device-to-device (D2D) services, LTE FeD2D services, NR (V2X) SL communications, and NR SL discovery) are enabled, and the (LTE / NR) cell may provide SL configuration and SL resource allocation to the UE. For UEs under the coverage of a cellular network, the UE may need to perform SL operations based on the configuration of the RAN. In order to implement SL operations under the coverage of a RAN, the serving cell (or pre-occupied cell) may need to provide SL configuration and SL resource allocation to the UE. Specifically, two basic methods are provided below for SL resource allocation in LTE V2X services.

[0136] In one embodiment, the scheduled resource allocation may be characterized by:

[0137] The UE may need to be in the (LTE / NR) RRC_CONNECTED state to transmit data;

[0138] ·The UE can request SL resources from the eNB (by sending a SL buffer status report (SL-BSR: SL buffer status report) to the serving cell). The eNB schedules dedicated SL resources for the UE to transmit SCI and SL data. To achieve this, the eNB can request the UE to report the SL-BSR over the Uu interface. In addition, when the UE wants to transmit a SL-BSR to the eNB but valid UL resources do not exist, the UE can also trigger an SR on the UL physical resources (e.g., PUCCH) or initiate a random access procedure. In addition, SR resources (or configuration) and SR procedures are important for SL

[0139] Operation and uplink traffic may be common to both.

[0140] In another embodiment, the UE autonomous resource selection from the SL resource pool may be characterized by:

[0141] • UE autonomous resource selection may be applied for both RRC connected UEs (eg, through dedicated RRC signaling or through SI broadcast) and RRC deactivated / idle states (eg, through SI broadcast).

[0142] • A resource pool may be a set of (almost contiguous) resource blocks, and the UE may autonomously decide which physical resource blocks the UE wants to apply for SL packet transmission.

[0143] UE can select resources from the resource pool and perform transport format selection to transmit SL control information and data;

[0144] · Before SL packet transmission, the UE may perform sensing for (re)selection of SL resources. Based on the sensing results, the UE (re)selects some specific SL resources and reserves multiple SL resources. The UE may be allowed to perform up to 2 parallel (independent) resource reservation processes. The UE may also be allowed to perform a single resource selection for its V2X SL transmission.

[0145] It is also noted that when the UE is out of RAN coverage on a frequency used for V2X SL communication, and if the BS discovered by the UE on the relevant SL frequency carrier does not provide V2X SL configuration for that frequency, the UE may use a set of transmission and reception resource pools preconfigured in the UE. V2X SL communication resources may not be shared with other non-V2X data transmitted over SL. In some embodiments, the UE may obtain pre-configuration through an installed Universal Mobile Telecommunication System (UMTS) Subscriber Identity Module (USIM), a stored memory, or through a RAN to which the UE has previously accessed. In addition, the UE may implement the PC5 interface by synchronizing with a Global Navigation Satellite System (GNSS) and applying pre-configuration. In this case, the PC5 interface may be independent of the RAN and (LTE / NR) Uu interfaces.

[0146] V2X queuing scenarios

[0147] Reference Figure 2 , Figure 2 FIG. 2 shows a V2X platoon scenario according to an exemplary embodiment of the present disclosure. Figure 2 As shown, queue X may include vehicle A, vehicle B, vehicle C, and vehicle D, and there may be (at least) one scheduler (eg, vehicle A) in the queue. In queue X, vehicle A may configure SL resources to members in the same queue by the following method.

[0148] Method similar to Mode 1: The scheduler may configure dynamic SL grants (e.g., dynamic SL grants via SCI) to members in the same queue. In addition, the scheduler may also configure semi-periodic SL grants (e.g., configured SL grants) to the UE via SL control signaling (e.g., via a physical sidelink broadcast channel (PSBCH) or SL RRC signaling). In order to implement a method similar to Mode 1, the scheduler may require the UE to provide feedback information via one or more PC5 interfaces.

[0149] Similar to Mode 2 approach: The scheduler may configure the SL resource pool to members in the same queue. The UE may automatically select SL grant by the UE itself (e.g., SL grant selection with or without sensing). Queuing scenarios may be applied when the vehicles of the queue are in coverage (i.e., all vehicles in the queue are within the coverage of the cellular RAN), out of coverage (i.e., all vehicles in the queue are outside the coverage of the cellular RAN), or in partial coverage (i.e., some UEs in the queue are within the coverage of the cellular RAN and other UEs in the queue are outside the coverage of the cellular RAN).

[0150] In some implementations, in order to support the scheduler, members in the queue may need to support the following to report their status to the scheduler via the PC5 interface:

[0151] SL-SR configuration and reporting

[0152] SL-Buffer Status Report (SL-BSR) configuration and reporting

[0153] SL-Power Headroom Report (SL-PHR) configuration and reporting

[0154] Reference Figure 3 , Figure 3 FIG. 5 shows a PC5-RRC connection between a pair of UEs according to an exemplary embodiment of the present disclosure. Specifically, the concept of a PC5-RRC connection may be different from an RRC connection in a Uu interface. In an NR PC5 interface, an SL-unicast group (e.g., Figure 3UE#1 and UE#2 shown) may need to establish (at least) one PC5-S connection, and each PC5-S connection may be independently associated with a PC5-RRC connection in the access layer (AS layer). In other words, the PC5-S connection and the PC5-RRC connection may be a one-to-one mapping. Each PC5 RRC connection is a logical connection between a pair of source and destination layer-2IDs. At the service level, a PC5-S connection (and therefore an associated PC5-RRC connection) may be established to serve one or more SL operations (e.g., SL operations supporting one or more NR / LTE V2X services). In some embodiments, for example, the PC5-S connection #1s at UE#1 and UE#2 are constructed to serve V2X services #1 / #2, and the PC5-S connection #2s are constructed to serve V2X services #a / #b. It is worth noting that there may be multiple valid PC5-S connections / PC5-RRC connections in paired UEs to support different groups of V2X services with different QoS requirements. In some embodiments, the UE may also report the status of the PC5-RRC connection to the serving cell (e.g., a PCell in a primary cell group or a PSCell in a secondary cell group), so that the serving RAN may also be aware of the condition of the PC5-RRC connection on the UE side. In addition, the UE may also report SL radio link failure events (to at least one PC5-RRC connection) to the serving RAN (e.g., for SL resource management, such as a SL resource configuration method similar to Mode 1). Please also note that the UE may also join multiple SL-unicast groups with different target UEs, and the UE may have PC5-RRC connections associated with different UEs.

[0155] Sidelink-Discontinuous Reception (SL-DRX)

[0156] In some embodiments, the MAC entity may be configured by an RRC having a SL-DRX function that controls the UE's SL packet reception (e.g., physical sidelink control channel (PSCCH) monitoring) activity and / or the UE's SL packet transmission (e.g., physical sidelink shared channel (PSSCH) transmission) activity.

[0157] If SL-DRX is configured, for all associated SL (e.g., unicast, multicast and / or broadcast) groups, the MAC entity may use SL-DRX operation to non-continuously monitor the PSCCH. Otherwise, the MAC entity may monitor the PSCCH for SL packet reception. If SL-DRX is configured, for all associated SL (e.g., unicast, multicast and / or broadcast) groups, the MAC entity may use SL-DRX operation to non-continuously transmit sidelink control information (SCI: Sidelink Control Information) on the configured PSCCH. Specifically, in some embodiments, the RRC entity may control the DRX operation by configuring the following parameters:

[0158] SL-drx-onDurationTimer: This duration can be at the beginning of the SL-DRX cycle;

[0159] SL-drx-SlotOffset: This delay can be before starting SL-drx-onDurationTimer;

[0160] SL-drx-InactivityTimer: This duration may be after a PSCCH opportunity where the PSCCH indicates a new SL transmission / reception for the concerned MAC entity;

[0161] drx-RetransmissionTimerSL_Rx (e.g., for each SL-HARQ reception process for which a UE needs to transmit SL-HARQ feedback information to an associated SL-Tx UE): this may be the maximum duration until a SL retransmission is received;

[0162] drx-RetransmissionTimerSL_Tx (e.g., the UE needs to retransmit each SL-HARQ transmission process of the SL MAC PDU based on the SL-HARQ feedback information replied by (at least) one SL-Rx UE): this may be the maximum duration until a grant for SL retransmission is received;

[0163] SL-drx-LongCycleStartOffset: This may be a long SL-DRX cycle and drx-StartOffset including the subframe defining where the long DRX cycle or short DRX cycle starts;

[0164] SL-drx-ShortCycle (optional): This can be a short SL-DRX cycle;

[0165] SL-drx-ShortCycleTimer (optional): This may be the duration for which the UE follows a short SL-DRX cycle;

[0166] drx-HARQ-RTT-TimerSL_Rx (e.g., for each SL-HARQ reception process for which the UE needs to transmit SL-HARQ feedback information to the associated SL-Tx UE): This may be the minimum duration before the MAC entity expects a SL allocation for SL-HARQ reception;

[0167] drx-HARQ-RTT-TimerSL_Tx (e.g., the UE needs to retransmit each SL-MAC PDU based on the SL-HARQ feedback information replied by (at least) one SL-Rx UE)

[0168] HARQ transmission progress): This may be the minimum duration before the MAC entity expects a SL-HARQ retransmission grant.

[0169] In some embodiments, when the SL-DRX cycle is configured, the (SL-DRX) active time (in the PC5 interface) may include the following times:

[0170] ·SL-drx-onDurationTimer or SL-drx-InactivityTimer or drx-

[0171] RetransmissionTimerSL_Tx or drx-RetransmissionTimerSL_Rx is running; or

[0172] · The SR for SL dynamic grant request is sent on the Physical Uplink Control Channel (PUCCH) (Uu interface) and is pending; or

[0173] • The PSCCH indicates one (or more) new transmissions addressed to one of a set of (associated SL source identity, interested SL (Layer 1 / Layer 2) destination identity) MAC entities of (at least) the UE.

[0174] In some embodiments, when SL-DRX is configured, the MAC entity may:

[0175] 1> If a SL MACPDU associated with the UE is received in the configured SL allocation (associated SL source identity, interested SL destination identity):

[0176] 2> (for example, if the UE is configured to transmit SL-HARQ feedback information about the corresponding SL-HARQ process associated with the corresponding destination identifier), after the corresponding transmission carrying the SL-HARQ feedback ends, start the drx-HARQ-RTT-TimerSL_Rx for the corresponding SL-HARQ process in the first symbol;

[0177] 2> Stop drx-RetransmissionTimerSL_Rx for the corresponding SL-HARQ process.

[0178] 1> If the SL MAC PDU is transmitted in the configured SL grant:

[0179] 2> After the transmission (or first repetition) of the corresponding PSSCH transmission ends, start the drx-HARQ-RTT-TimerSL_Tx for the corresponding SL-HARQ process in the first symbol;

[0180] 2> Stop drx-RetransmissionTimerSL_Tx for the corresponding SL-HARQ process.

[0181] 1> If drx-HARQ-RTT-TimerSL_Rx expires:

[0182] 2> If the data of the corresponding SL-HARQ process is not successfully decoded:

[0183] 3>After drx-HARQ-RTT-TimerSL_Rx expires, drx-RetransmissionTimerSL_Rx for the corresponding SL-HARQ process is started in the first symbol.

[0184] 1> If drx-HARQ-RTT-TimerSL_Tx expires:

[0185] 2> After the drx-HARQ-RTT-TimerSL_Tx expires, start the drx-RetransmissionTimerSL_Tx for the corresponding SL-HARQ process in the first symbol.

[0186] 1> If a DRX command MAC control element (CE: Control Element) (or SL-DRX command) or a long DRX command MAC CE (or SL-long DRX command MAC CE) is received from the serving cell (through the Uu interface) or from other UEs (through the PC5 interface):

[0187] 2>Stop SL-drx-onDurationTimer;

[0188] 2>Stop SL-drx-InactivityTimer.

[0189] 1> If SL-drx-InactivityTimer expires or a DRX command MAC CE (or SL-DRX command) is received:

[0190] 2> If the short SL-DRX cycle is configured as:

[0191] 3> After the SL-drx-InactivityTimer expires or in the first symbol or after the DRX command MAC CE (or SL-DRX command) is received, start or restart the SL-drx-ShortCycleTimer in the first symbol;

[0192] 3> Use short SL-DRX cycle.

[0193] 2> Otherwise:

[0194] 3> Use long SL-DRX cycle.

[0195] 1> If SL-drx-ShortCycleTimer expires:

[0196] 2> Use a long SL-DRX cycle.

[0197] 1> If a long SL-DRX command (Long DRX Command MAC CE) is received:

[0198] 2>Stop SL-drx-ShortCycleTimer;

[0199] 2> Use a long SL-DRX cycle.

[0200] 1> if a short SL-DRX cycle is used, and [(SFN×10)+subframe number] modulo(SL-drx-ShortCycle)=(SL-drx-StartOffset) modulo(SL-drx-ShortCycle); or

[0201] 1> If a long SL-DRX cycle is used, and [(SFN×10)+subframe number] modulo(SL-drx-LongCycle)=SL-drx-StartOffset:

[0202] 2> Start SL-drx-onDurationTimer after SL-drx-SlotOffset from the start of the subframe.

[0203] 1> If the MAC entity is in (SL-DRX) active time:

[0204] 2> (continuously) monitor the PSCCH of one (or more) SL frequency carriers;

[0205] 2> If PSCCH indicates SL transmission:

[0206] 3> After the corresponding transmission carrying SL-HARQ feedback ends, start the drx-HARQ-RTT-TimerSL_Rx for the corresponding transmission HARQ process in the first symbol;

[0207] 3> Stop drx-RetransmissionTimerSL_Rx for the corresponding SL-HARQ process.

[0208] 2> If the UE transmits SCI on a PSCCH, the SCI indicates SL transmission:

[0209] 3> After the transmission (or first repetition) of the corresponding PSSCH transmission ends, start the drx-HARQ-RTT-TimerSL_Tx for the corresponding SL-HARQ process in the first symbol;

[0210] 3> Stop drx-RetransmissionTimerSL_Tx for the corresponding SL-HARQ process.

[0211] 2> If the PSCCH indicates a new SL packet transmission to the UE (or indicates SL control signaling), or the UE transmits SCI on a PSCCH:

[0212] 3> Start or restart the SL-drx-InactivityTimer in the first symbol after the associated PDCCH ends.

[0213] In some embodiments, if it is not a complete PSCCH opportunity (e.g., the (SL-DRX) active time starts or ends in the middle of a PSCCH opportunity), the MAC entity may not need to monitor the PSCCH. Also note that in some embodiments, there may not be an additional SL-DRX mechanism. Instead, the UE can adjust the SL packet transmission / reception based on the SL-DRX mechanism.

[0214] It is worth noting that the connected mode DRX (C-DRX) mechanism has been applied in the LTE / NR Uu interface for power saving on the UE side. In contrast, in LTE / NR(V2X)SL operations (e.g., LTE / NR(V2X)SL communications), there is no similar mechanism to reduce power waste on the UE side. Therefore, the SL-DRX mechanism is introduced to include the definition of SL-DRX active time (ActiveTime), SL-DRX on-duration (On-Duration), SL-DRX off-period, and related UE behaviors during the proposed SL-DRX active time (SL-DRX on-duration) and SL-DRX off-period.

[0215] Specifically, in some embodiments, the mechanism may be based on the condition that the UE is in the RRC connected state. Note that the proposed mechanism may also be implemented for UEs in the RRC deactivated state and / or the RRC idle state.

[0216] In some embodiments, the mechanism may be based on the condition that the UE can achieve SL communication within the coverage of the serving RAN (e.g., SL unicast group, SL multicast (groupcast) group, and the entire group is under the coverage of the serving RAN). Note that the mechanism can also be implemented to SL unicast / multicast groups, which are out of coverage (do not have a valid Uu interface with any RAN) or in partial coverage (only a subset of the group members in the group have a valid Uu interface with its serving RAN (e.g., valid DL / UL data or signaling exchange over the Uu interface)).

[0217] In some embodiments, the mechanism may be applied based on NR RAT (e.g., NR Uu interface and NR PC5 interface). It is worth noting that the mechanism may also be applicable to other RATs (e.g., LTE Uu interface and LTE PC5 interface).

[0218] In some embodiments, the concepts of short DRX cycle and long DRX cycle (and switching between short DRX cycle / long DRX cycle) in the C-DRX mechanism can be applied to the SL-DRX mechanism. Of course, the SL-DRX mechanism can also be configured with only short DRX cycle or long DRX cycle.

[0219] In some embodiments, the SL-DRX command may be transmitted to the UE by the serving RAN (which constitutes one or more serving cells / BSs / gNBs) via the (LTE / NR) Uu interface through dedicated control signaling (e.g., PHY signaling (e.g., downlink control information (DCI) via PDCCH), or MAC CE or dedicated RRC signaling transmitted via a physical downlink shared channel (PDSCH), or any combination of the three signaling methods.

[0220] In some embodiments, the SL-DRX command may be transmitted by a UE (e.g., a queue leader in a SL unicast / multicast group) to member UEs via a PC5 interface via dedicated control signaling (e.g., MAC CE multiplexed with other SL packets in PSSCH and / or dedicated PC5-RRC signaling sent over PSSCH (e.g., over an associated PSSCH)). In additional embodiments, the SL-DRX command may be transmitted via (at least) SCI in an associated PSCCH.

[0221] SL-DRX Mechanism

[0222] Reference Figure 4 , Figure 4 FIG. 4 shows an SL-DRX configuration according to an exemplary embodiment of the present disclosure. Figure 4 As shown, in the PC5 interface, the UE may 'wake up' at the beginning of the SL-DRX on duration (or from the beginning of the SL-DRX active time). The UE may then implement relevant / configured mechanisms during the SL-DRX on duration. The UE may then switch from the SL-DRX on duration (or from the SL-DRX active time) to the SL-DRX off period based on defined conditions. In some embodiments, the UE may remain in the SL-DRX off period for a period of time, and the behavior for the UE remaining in the SL-DRX off period may also be provided in the following paragraphs. As Figure 4 As shown, the SL-DRX off period may be terminated when the UE wakes up at the beginning of the next SL-DRX on duration.

[0223] In detail, in one embodiment, the meaning of "the UE can wake up" means that the UE can start monitoring control information from the associated physical control channel (for example, the UE can wake up to monitor the SCI of at least one associated PSCCH in the (LTE / NR) PC5 interface (for example, the first stage SCI when the two-stage SCI transmission mechanism is applied) and / or the UE can wake up to monitor the DCI of (at least) one associated PDCCH in the (LTE / NR) Uu interface). Optionally, in one embodiment, the meaning of "the UE can wake up" means that the UE can remain within the DRX (for example, C-DRX and / or SL-DRX) active time. Optionally, in one embodiment, the meaning of "the UE can wake up" means that the UE can start the drx-onDurationTimer (and / or the SL-drx-onDurationTimer in the (LTE / NR) PC5 interface). Optionally, in one embodiment, the meaning of "the UE can wake up" means that the UE can start the drx-onDurationTimer (and / or the SL-drx-onDurationTimer in the (LTE / NR) PC5 interface). Optionally, in one embodiment, the meaning of "the UE can wake up" means that the UE can (re)start the drx-onDurationTimer (and / or the SL-drx-onDurationTimer in the (LTE / NR) PC5 interface). Optionally, in one embodiment, “UE can wake up” means that the UE can (re)start the drx-InactivityTimer (and / or SL-drx-InactivityTimer in the (LTE / NR) PC5 interface).

[0224] In some embodiments, Figure 4 As shown, a SL-DRX cycle may include a SL-DRX on duration and a subsequent SL-DRX off period. Parameters for the SL-DRX mechanism (e.g., the value of the SL-DRX cycle / SL-DRX on duration) (and control mechanisms / rules regarding UE / RAN behavior during the SL-DRX active time / SL-DRX off period) may be explicitly configured by the serving RAN via a broadcast message (e.g., SI broadcast or via SI on-demand procedure) or via dedicated control signaling in the (LTE / NR) Uu interface (e.g., RRC (connection) reconfiguration message or other RRC messages, such as RRC (connection) release message, RRC (connection) release message with suspension configuration, RRC (connection) release message without suspension configuration, RRC (connection) establishment message, RRC (connection) reestablishment message, RRC (connection) rejection message, RRC (connection) recovery message).

[0225] In some embodiments, parameters for the SL-DRX mechanism (and proposed control mechanisms / rules regarding UE / RAN behavior during SL-DRX active time / SL-DRX off period in a SL-DRX cycle) can be configured by other UEs (e.g., by broadcasting SL-MIB or dedicated PC5-RRC signaling) via the (LTE / NR) PC5 interface. More specifically, SL-DRX corresponding parameters (e.g., the value of the SL-DRX cycle / SL-DRX on duration) can be configured via a DRX configuration for the SL, which can be configured for each MAC entity and / or cell group (e.g., MCG or SCG). In addition, the SL-DRX cycle can include short SL-DRX cycles and / or long SL-DRX cycles, and the UE can decide which SL-DRX cycles to apply based on predefined rules. In some embodiments, parameters for the SL-DRX mechanism (and proposed control mechanisms / rules regarding UE / RAN behavior during SL-DRX active time / SL-DRX off period in a SL-DRX cycle) can be predefined as needed in the 3GPP TS series specifications, or preinstalled in a memory module on the UE side (e.g., USIM).

[0226] Please note that in some embodiments, (part of) the SL-DRX parameters may be applicable to the C-DRX parameters. For these parameters, as provided in Table 1 for C-DRX:

[0227] (a) The UE can configure the length of the SL-DRX on duration = drx-onDurationTimer;

[0228] (b) The UE may configure the length of the SL-DRX cycle = drx-ShortCycle.

[0229] (c) The design related to the long DRX cycle may also be applied to the SL-DRX configuration. Moreover, in some additional embodiments, the UE may be configured with a long SL-DRX cycle by applying the drx-LongCycleStartOffset received in the DRX-Config.

[0230] Moreover, in some embodiments, the UE can "wake up" in the (LTE / NR) Uu interface and the (LTE / NR) PC5 interface at the same time. For example, one MAC entity of the UE can perform associated DRX operations for the Uu interface, and another MAC entity of the UE can perform associated SL-DRX operations for the PC5 interface. For another example, one MAC entity of the UE can jointly (and simultaneously) perform the same DRX operations on the Uu interface and the PC5 interface. Then, in some embodiments, the UE can switch to a DRX disconnect period in the Uu interface and to a SL-DRX disconnect period in the PC5 interface at different timings (for example, depending on the packet switching status in the Uu interface and the PC5 interface (or depending on different DRX operations)).

[0231] In some embodiments, the UE may be configured with two C-DRX groups having two different sets of parameters. In addition, the SL-DRX mechanism may apply one or more parameters from one of two different parameter sets corresponding to one of the two C-DRX groups. The selection between different parameter sets may be indicated by a serving RAN (e.g., via dedicated RRC signaling) or other UEs (e.g., via dedicated PC5-RRC signaling) in the same SL unicast / multicast / broadcast group as the target UE. More specifically, the two C-DRX groups may be configured for the same MAC entity and / or cell group (e.g., MCG / SCG).

[0232] Table 1

[0233]

[0234]

[0235] UE behavior during SL-DRX active time (or SL-DRX on duration) or SL-DRX off period

[0236] In some implementations, SL-DRX may affect the behavior of the UE in the following circumstances:

[0237] ·(a) SL transmission (in PC5 interface): Some implementations in which the UE may stop SL packet transmission while the UE remains in a SL-DRX off period. A more detailed mechanism may be presented as follows. In some embodiments, the UE may be configured with SL packet transmission (or simply SL packet) over both the LTE PC5 interface and the NR PC5 interface. In some embodiments, during the SL-DRX off period, the UE may: (1) stop only SL packet transmission on the LTE PC5 interface (therefore, SL packet transmission on the NR PC5 interface may continue during the SL-DRX off period), (2) stop only SL packet transmission on the NR PC5 interface (therefore, SL packet transmission on the LTE PC5 interface may continue during the SL-DRX off period), or (3) stop SL packet transmission on both the LTE PC5 interface and the NR PC5 interface.

[0238] ·(b) SL Reception: Some embodiments in which the UE may stop SL packet reception while the UE remains in a SL-DRX OFF period. A more detailed mechanism is discussed below. In some embodiments, the UE may be configured with SL packet reception over both the LTE PC5 interface and the NR PC5 interface. In some embodiments, during the SL-DRX OFF period, the UE may: (1) stop SL packet reception only on the LTE PC5 interface (thus, SL packet reception on the NR PC5 interface may continue during the SL-DRX OFF period), (2) stop SL packet reception only on the NR PC5 interface (thus, SL packet reception on the LTE PC5 interface may continue during the SL-DRX OFF period), or (3) stop SL packet transmission on both the LTE PC5 interface and the NR PC5 interface.

[0239] ·(c) SL-Uu related mechanisms to the RAN (in the (LTE / NR)Uu interface): When the UE remains in the SL-DRX off period, the UE may stop reporting some embodiments of the UE to the RAN (via the (LTE / NR)Uu interface), or when the UE remains in the SL-DRX off period, the UE may stop listening to RAN instructions. More detailed mechanisms are discussed below. In some embodiments, the UE may be configured with an NR Uu interface to support SL resource configuration for both the LTE PC5 interface and the NR PC5 interface (for example, the BS may configure dynamic SL authorization or SL (exceptional) resource pool configuration for the NR PC5 interface (such as a PC5 RRC connection)). The BS may also configure the SL (exceptional) resource pool configuration for the LTE PC5 interface. In some embodiments, during the SL-DRX off period, the UE may: (1) stop only the SL-Uu related mechanisms associated with the LTE PC5 interface (thus, the SL-Uu related mechanisms associated with the NR PC5 interface (e.g., one or more PC5 RRC connections) may continue during the SL-DRX off period), (2) stop only the SL-Uu related mechanisms associated with the NR PC5 interface (thus, the SL-Uu related mechanisms associated with the LTE PC5 interface may continue during the SL-DRX off period), or (3) stop the SL-Uu related mechanisms associated with both the LTE PC5 interface and the NR PC5 interface.

[0240] (d) SL synchronization mechanism: Even if the UE is configured as a (LTE / NR) SyncRefUE, the UE may stop broadcasting the SL-SSB (with or without MIB-SL or MIB-SL-V2X) when the UE remains in the SL-DRX off period. The UE may then broadcast the SL-SSB (with or without MIB-SL or MIB-SL-V2X) again at the beginning of the SL-DRX on duration (in the next SL-DRX cycle) after the UE wakes up. A more detailed mechanism is discussed below. In some embodiments, the UE may be configured as an NR SyncRef UE and an LTE SyncRef UE. In some embodiments, during the SL-DRX off period, the UE may: (1) stop only LTE SyncRef UE operation on the LTE PC5 interface (therefore, NRSyncRef UE operation on the NR PC5 interface can continue during the SL-DRX off period), (2) stop only NRSyncRef UE operation on the NR PC5 interface (therefore, LTE SyncRef UE operation on the LTE PC5 interface can continue during the SL-DRX off period), or (3) stop NRSyncRef UE operation and LTE SyncRef UE operation on the NR PC5 interface and LTE PC5 interface, respectively, during the SL-DRX off period.

[0241] ·(e) SL discovery mechanism: When the UE remains in the SL-DRX off period, the UE may stop transmitting (LTE / NR) SL discovery messages. Then, after the UE wakes up at the beginning of the subsequent SL-DRX on duration, the UE may start / resume / continue transmitting (LTE / NR) SL discovery messages again. A more detailed mechanism is discussed below. In some embodiments, the UE may be configured with LTE SL discovery message delivery and NR SL discovery message delivery. In some embodiments, during the SL-DRX off period, the UE may: (1) only stop LTE SL discovery message delivery on the LTE PC5 interface (so NRSL discovery message delivery on the NR PC5 interface may continue during the SL-DRX off period), (2) only stop NR SL discovery message delivery on the NR PC5 interface (so LTE SL discovery message delivery on the LTE PC5 interface may continue during the SL-DRX off period), or (3) during the SL-DRX off period, stop LTE SL discovery message delivery and NR SL discovery message delivery on the LTE PC5 interface and the NR PC5 interface, respectively.

[0242] (f) PC5-RRC connection: In some embodiments, when the UE remains in the SL-DRX off period, the UE may stop SL operations associated with all or a subset of the PC5-RRC connections configured on the UE side (e.g., SL packet transmission / reception, PC5-RRC signaling transmission / reception, or PC5-S signaling through the associated PC5-RRC connection). Then, when the UE remains in the SL-DRX active time, the UE may (re)-start / resume / continue SL operations associated with all or a subset of the PC5-RRC connections configured on the UE side. Conversely, in some additional embodiments, regardless of whether the UE remains in the SL-DRX active time or the SL-

[0243] During the DRX off period, SL operations associated with the SL multicast / broadcast group (e.g., the UE is not configured with a PC5-RRC connection with an associated target SL destination identifier) ​​may still continue.

[0244] Considering the SL transmission mechanism, first, the SCI transmission in PSCCH and the SL packet delivery in PSSCH can be disclosed. In some embodiments, the SL-Tx UE can be defined as a UE that wants to send SL data packets and / or control signaling to other UEs through the (LTE / NR) PC5 interface. Then, the SL-Rx UE is defined as a UE that wants to receive SL packets and / or control signaling from other UEs through the (LTE / NR) PC5 interface. In some embodiments, the UE can be a SL-Tx UE or a SL-Rx UE, and the UE can switch its role between the SL-Tx UE and the SL-Rx UE. In some embodiments, the UE can be a SL-Tx UE and a SL-Rx UE at the same time. Note that the SL-Tx UE behavior may not be limited to the behavior of the SL-Tx UE, but may also include the behavior of the SL-Rx UE. Moreover, the SL-Rx UE behavior may not be limited to the behavior of the SL-Rx UE, and may also include the behavior of the SL-Tx UE. For example, in one embodiment, the SL-TX UE generally requires a sensing process for transmission. On the contrary, the SL-Rx UE may also perform the sensing process (in the background embodiment) because it may act as a SL-Tx UE when requesting to transmit a SL packet, which does not limit the scope of the embodiment.

[0245] In some embodiments, during the SL-DRX off period (even if there is at least one pending SL packet on the UE side and there are available SL resources (pool) during the SL-DRX off period), the UE may stop transmitting SCI in the configured PSCCH (for example, for the two-stage SCI delivery mechanism, the SCI may be considered as the first-stage SCI (or referred to as the first SCI)). Therefore, during the SL-DRX off period, the UE may not send SL packets (with a multiplexed demodulation reference signal (DMRS: De-Modulation Reference Signal)) in the PSSCH.

[0246] In some embodiments, when the UE remains in the SL-DRX off period, the UE may stop accessing the grants configured for type 1 SL. (In some embodiments, for the RAN side, the serving RAN may reallocate SL resources to other UEs) In another embodiment, when the UE remains in the SL-DRX off period, the UE may still access (all or a subset of) the grants configured for type 1 SL.

[0247] In some embodiments, the UE may stop accessing grants of an 'active' Type 2 SL configuration while the UE remains in a SL-DRX off period. (In some embodiments, for the RAN side, the serving cell may reallocate SL resources to other UEs during the UE's SL-DRX off period). In another embodiment, the UE may still access (all or a subset of) grants of an active Type 2 SL configuration while the UE remains in a SL-DRX off period.

[0248] In some embodiments, for mode 2 SL resource configuration, the UE may stop accessing the SL pool when the UE remains in the SL-DRX off period.

[0249] In some embodiments, for the SL exception resource pool, when the UE remains in the SL-DRX off period, the UE may stop accessing the SL exception resource pool. In some embodiments, when the UE remains in the SL-DRX off period, the UE may maintain access to the SL exception resource pool.

[0250] In some embodiments, for one or more SL-HARQ processes, the UE may suspend the ongoing (or activated) SL-HARQ process after the UE moves to the SL-DRX off period. While the UE remains in the SL-DRX off period, the UE may maintain the suspended SL-HARQ process (e.g., the UE may suspend all activated counters / timers associated with the SL-HARQ process). For example, for SL-HARQ processes associated with low priorities (e.g., SL logical channels with high Prose-Per-Packet Priority (PPPP) thresholds (such as 7, 8)) (e.g., pending packets associated with a specific SL-HARQ process ID and related activated SL-HARQ timers), the SL-HARQ processes with these low priority SL logical channels may be suspended during the SL-DRX off period. In addition, the PPPP threshold may be further configured to the UE (e.g., via dedicated (PC5-)RRC signaling or broadcast SI). A SL assembled MAC PDU provided with an associated PPPP value higher than (and equal to) a given PPPP threshold may be considered as a low priority SL MAC PDU. Then, the SL transmission / reception and / or SL-HARQ process associated with the low priority MAC PDU may also be suspended during the SL-DRX off period. Otherwise, an assembled MAC PDU provided with an associated PPPP value lower than a given PPPP threshold may be considered as a high priority SL logical channel. Then, during the SL-DRX off period, the SL transmission / reception and / or SL-HARQ process associated with these high priority SL-HARQ processes may not be suspended. In some embodiments, the PPPP value of the assembled MAC PDU may be determined by the lowest PPPP value (e.g., the highest priority PPPP value) among the logical channels having pending packets included in the payload of the associated MAC PDU. Of course, the implementation and mapping rules of the SL logical channels and PPPP thresholds may be referred to as LTE V2X (SL) communication.

[0251] In some embodiments, the SL resources may span one or more SL frequency carriers on which the UE is configured to transmit SL packets (and SL control signaling, such as PC5-RRC signaling). In such a case, the UE may implement the SL-DRX mechanism on multiple SL frequency carriers simultaneously. In addition, in some embodiments, the UE may be configured with multiple SL-DRX parameter sets, each of which may be independently applied to different SL frequency carrier sets (e.g., two SL-DRX parameter sets for SL frequency carriers in FR1 (frequency carriers below 7 GHz) and FR2 (frequency carriers above 7 GHz), respectively).

[0252] In some embodiments, a subset of the SL transmission resource pool may be configured for the UE to transmit SL packets even during the SL-DRX off period. For example, the SL-DRX-Tx resource pool configuration set may be configured to the UE (e.g., by SL pre-configuration; by dedicated control signaling in the (LTE / NR) Uu interface, such as an RRC (connection) reconfiguration message; by dedicated signaling in the PC5 interface, such as PC5-RRC signaling; by broadcast messages, such as SI; by SI on-demand process). Then, after the UE moves to the SL-DRX off period, the UE may start accessing the SL-DRX-Tx resource pool. Moreover, in some embodiments, the SL-DRX-Tx resource pool configuration may also include a SL exception resource pool, which may be configured for the SL-Tx UE to send SL packets when at least one exception condition is met. In some embodiments, the SL-DRX-Tx resource pool configuration provided for the SL-DRX active time / off period may not include the SL exception resource pool. It is worth noting that in some embodiments, the definition of the SL-DRX active time may only take into account the count of the SL-drx-onDurationTimer. In other words, after the SL-drx-onDurationTimer expires (and the (SL-DRX) active time in the PC5 interface has also ended), the UE can directly switch from the SL-DRX on duration to the SL-DRX off period. Then, within the SL-DRX cycle, the UE can apply different sets of SL transmission resources in the SL-DRX on duration and the SL-DRX off period, respectively. In some embodiments, separate SL (transmission) resource pool configurations may be configured for the SL-DRX on duration (or SL-DRX active time) and the SL-DRX off period, respectively. In some embodiments, the SL (transmission) resource pool configurations configured for the SL-DRX on duration (or SL-DRX active time) and the SL-DRX off period may be isolated from each other in the physical resource block (PRB: Physical resourceblock) allocation. In some embodiments, the SL (transmission) resource pool configurations configured for the SL-DRX on duration (or SL-DRX active time) and the SL-DRX off period may partially overlap in PRB allocation.

[0253] In some embodiments, when the UE remains in the SL-DRX off period, the UE may stop transmitting PC5-RRC signaling to the peer UE. The PC5-RRC signaling may then be stored in a buffer on the SL-Tx UE side. The SL-Tx UE may restart PC5-RRC signaling transmission in the next SL-DRX on duration. Therefore, some specific processes (e.g., SL UE capability query / exchange signaling and SL resource (pool) configuration / query process in the PC5 interface) may also be terminated when the UE remains in the PC5 off period. Moreover, while the UE remains in the SL-DRX off period, the RRC processes associated with these PC5-RRC signaling may be terminated. Moreover, the valid / ongoing counters or timers associated with these terminated PC5-RRC processes may also be terminated during the SL-DRX off period. Then, after the UE moves to the SL-DRX on duration again, the UE may re-count the terminated counters / timers.

[0254] In some embodiments, the SL resources used for SL transmission may include one or more SL frequency carriers, where the UE can listen to the SL packet transmission.

[0255] In some embodiments, for a UE that remains within the SL-DRX OFF period, the UE may decide whether to switch to the SL-DRX ON duration (e.g., starting the SL-drx-onDurationTimer after SL-drx-SlotOffset (≥0) from the start of the corresponding subframe in the PC5 interface) based on whether there are any pending SL packets (SL control signaling) on ​​the UE side. In other words, if there are one or more pending SL packets in the buffer, the UE may switch from the SL-DRX OFF period to the SL-DRX ON duration at the beginning of the SL-DRX cycle (and start the SL-drx-onDurationTimer from the start of the corresponding subframe (after SL-drx-SlotOffset)). Conversely, if there are no pending packets in the buffer, the UE may decide to remain in the SL-DRX OFF period (and not start the SL-drx-onDurationTimer after SL-drx-SlotOffset from the start of the corresponding subframe).

[0256] Second, in order to consider the SL transmission mechanism, a sensing mechanism may be disclosed. In some embodiments, the SL-Tx UE may implement a SL sensing or partial sensing mechanism to select target SL resource blocks for SL packet transmission in LTE V2X SL communication and NR SL operation.

[0257] In some embodiments, during the SL-DRX off period, the UE may stop implementing SL sensing or partial sensing mechanisms.

[0258] Referring to FIG. 5( a ), FIG. 5( a ) shows a side link sensing window according to an exemplary embodiment of the present disclosure. In some embodiments, during the SL-DRX off period, the UE may be configured as a "side link sensing window" period. As shown in FIG. 5( a ), before the start of the SL-DRX on duration, the UE may start implementing the SL sensing or partial sensing mechanism in advance to prepare for SL packet transmission in the upcoming SL-DRX on duration.

[0259] Based on (a) of Figure 5, in some embodiments, the UE may monitor and decode the PSCCH located within the SL sensing window. In some embodiments, during the SL sensing window, the UE may not decode the SCI in the PSCCH or PSSCH. Instead, the UE may only monitor the received signal strength (e.g., SL-RSSI) or received power density (e.g., SL-RSRQ) of the PSCCH or PSSCH in the configured SL sensing window (e.g., by detecting each physical resource block associated with the PSCCH). In some embodiments, during the SL sensing window, the UE may monitor the power saving signaling (PSS: Power Saving Signalling) (or wake-up signaling (WUS: Wake-Up Signalling)) in the (LTE / NR) Uu interface for SL. Then, after the UE receives the PSS (or WUS) from the serving cell via the Uu interface, the UE may also wake up in the (LTE / NR) PC5 interface.

[0260] More specifically, in some embodiments, the PSS may be referred to as WUS, PDCCH-WUS, PDCCH-skipping, and / or sleep signaling. The PSS may be scrambled by a specific RNTI (eg, Power Saving-RNTI (PS-RNTI)). The PSS may include one or more of the following information: power saving techniques associated with C-DRX (e.g., waking up and / or entering sleep), cross-slot scheduling, triggering reference signal transmission, CSI-RS measurement reporting, single / multi-cell operation, bandwidth part information (e.g., BWP ID), secondary cell (SCell) information (e.g., SCell ID), multi-input multi-output (MIMO) layer adaptation (e.g., the maximum number of MIMO layers), the number of antennas, an indication of the control resource set (CORESET) / search space / candidate for subsequent PDCCH decoding, PDCCH monitoring period, PDCCH skipping, the number of skips for C-DRX monitoring, SPS (Semi-Persistent-Scheduling) activation, C-DRX configuration, C-DRX period, etc., which does not limit the scope of the implementation. The monitoring timing of the PSS can be "indicated" to the UE by the NW using an offset before and / or at the beginning of the C-DRX on duration (e.g., starting symbol / time slot / subframe). The indication to the UE may include explicit signaling through upper layer signaling or implicit signaling through CORESET / search space. For example, the serving RAN may configure an offset to the UE. The serving RAN may configure a specific CORESET and / or search space for the PSS. The serving RAN may configure a specific period for the PSS, for example, the period may be associated with the period of the DRX cycle. The UE may monitor the PSS at an offset before and / or at the beginning of the C-DRX on duration (e.g., the start symbol / time slot / subframe) on a specific CORESET and / or search space. The WUS may have a field to indicate that the UE needs to wake up or not wake up in the upcoming new C-DRX cycle. Alternatively, the WUS may not have an explicit field / format to indicate that the UE needs to wake up or not wake up. When the UE receives the WUS, the serving RAN may be implicitly instructed to wake up the UE (e.g., to listen to the PDCCH on the subsequent C-DRX on duration (i.e., so the UE can start the drx-onDurationTimer at the beginning of the subsequent C-DRX cycle)). If the UE does not receive any WUS at the WUS opportunity, the serving RAN may implicitly instruct the UE not to wake up (eg, not monitor PDCCH and remain in the C-DRX off period (ie, not start drx-onDurationTimer at the start of the subsequent C-DRX cycle)).

[0261] In other embodiments, the UE may decide whether to initiate a (partial) sensing mechanism at the beginning of the SL sensing window based on whether the UE has pending SL packets in the buffer. For example, the UE may initiate a (partial) sensing mechanism only when there are any pending SL packets on the SL-Tx UE side. On the contrary, if the UE does not have pending packets in its buffer, the UE may not trigger the SL (partial) sensing mechanism and the SL sensing window. Alternatively, the UE may decide whether to continue listening during the sensing window based on a specific indication (e.g., PSS and / or WUS), where the specific indication may be indicated during the sensing window.

[0262] Referring to (b) of Figure 5, (b) of Figure 5 shows the other side link sensing window according to an exemplary embodiment of the present disclosure. It is worth noting that, as shown in (b) of Figure 5, in some embodiments, the SL sensing window can be configured as a part of the SL-DRX on duration. In other words, only when the UE wakes up at the beginning of the SL-DRX on duration can the UE initiate the SL (partial) sensing mechanism. In addition, the UE can decide whether to transmit a SL packet in the SL-DRX on duration based on the (partial) sensing result.

[0263] Referring to (c) of Figure 5, (c) of Figure 5 shows the other side link sensing window according to an exemplary embodiment of the present disclosure. As shown in (c) of Figure 5, in some embodiments, when the UE remains in the SL-DRX off period, when a new SL packet arrives at the buffer on the UE side, the UE can initiate the SL (partial) sensing mechanism. In addition, the UE can apply the rule only to new SL packets belonging to specific (pre-configured) SL logical channels (e.g., logical channels with high priority, such as SL logical channels associated with low PPPP values / thresholds), some specific PPPP thresholds, or some specific PPPP values.

[0264] In some embodiments, the SL-Tx UE may be configured to implement a sensing mechanism or a partial sensing mechanism based on the SL-DRX mechanism. For example, the SL-Tx UE may implement a (partial) sensing mechanism during the SL-DRX on duration. Conversely, when the SL-Tx UE remains within the SL-DRX off period, the SL-Tx UE may implement a partial sensing mechanism. In addition, the sensing mechanism may not be interrupted during the transition between the SL-DRX on duration and the SL-DRX off period. In some embodiments, when the UE switches from the SL-DRX on duration (or SL-DRX active time) to the SL-DRX off period, or when the UE switches from the C-DRX on duration (or C-DRX active time) to the C-DRX off period, the UE may stop the (partial) sensing mechanism. In addition, if the (partial) sensing mechanism is stopped, the UE may also release the stored sensing results.

[0265] Third, the SL transmission mechanism may include channel busy ratio (CBR) measurement and channel occupancy.

[0266] In order to start with CBR measurement, in some embodiments, the UE may stop implementing CBR measurement during the SL-DRX off period. In some embodiments, the UE may be configured with another SL CBR window, which is also after the SL sensing window shown in (a) to (c) of Figure 5. In some embodiments, when the UE switches from the SL-DRX on duration (or SL-DRX active time) to the SL-DRX off period and / or when the UE switches from the SL-DRX off period to the SL_DRX active time (or SL-DRX on duration), the CBR measurement may not be interrupted.

[0267] Next, in order to take into account the channel occupancy, in some embodiments, the UE may stop performing channel occupancy measurements during the SL-DRX off period. In some embodiments, the UE may be configured with another SL channel occupancy window, which is also Figure 5(a) to Figure 5(c) After the SL sensing window shown in . In some embodiments, when the UE switches from the SL-DRX on duration (or SL-DRX active time) to the SL-DRX off period and / or when the UE switches from the SL-DRX off period to the SL-DRX on duration (or SL-DRX active time), the channel occupancy measurement may not be interrupted.

[0268] Fourth, the SL transmission mechanism may include a SL-BSR process. In some embodiments, the UE may exchange SL-BSR via the NR PC5 interface (e.g., via PC5-RRC signaling). In some embodiments, when the UE remains in the SL-DRX off period, the UE may not initiate a SL-BSR to a neighboring UE via the PC5 interface. In some embodiments, an ongoing SL-BSR process may be pending / suspended / postponed / cancelled during the SL-DRX off period. In some embodiments, when the UE remains in the SL-DRX off period, the UE may still initiate a SL-BSR process to a neighboring UE via the PC5 interface. In addition, the ongoing SL-BSR process may not be affected by the switch / conversion between the SL-DRX on duration and the SL-DRX off period.

[0269] Fifth, for the SL transmission mechanism, a SL-SR process may be included. In some embodiments, the UE may initiate a SL-SR process with (at least) one neighboring UE via a PC5 interface (e.g., via PC5-RRC signaling). In some embodiments, an ongoing SL-SR process may be pending / suspended / postponed / canceled during a SL-DRX off period. In some embodiments, when the UE remains within the SL-DRX off period, the UE may not initiate a SL-SR to a neighboring UE via the PC5 interface. In some embodiments, when the UE remains within the SL-DRX off period, the UE may still initiate a SL-SR process to a neighboring UE via the PC5 interface. In addition, the ongoing SL-SR process may not be affected by the switching / conversion between the SL-DRX on duration / SL-DRX off period.

[0270] Sixth, the SL transmission mechanism may include a SL-Power Headroom Report (SL-PHR: SL-Power HeadroomReport) process. In some embodiments, the UE may initiate a SL-PHR process with at least one neighboring UE through a PC5 interface (e.g., through PC5-RRC signaling). In some embodiments, when the UE remains in a SL-DRX off period, the UE may not initiate a SL-PHR to a neighboring UE through the PC5 interface. In some embodiments, an ongoing SL-PHR process may be pending / suspended / postponed / canceled during the SL-DRX off period. In some embodiments, when the UE remains in a SL-DRX off period, the UE may still initiate a SL-PHR process to a neighboring UE through the PC5 interface. In addition, the ongoing SL-PHR process may not be affected by the switching / conversion between the SL-DRX on duration / SL-DRX off period.

[0271] Seventh, the SL transmission mechanism may include one or more special conditions. In some embodiments, the UE may break the rule of stopping SL packet transmission (via SL dynamic grant, type 1 S1 configuration grant, type 2 S1 configuration grant, mode 2 SL resource pool configuration, or exception resource pool) when at least one exceptional condition occurs, such as:

[0272] (a) If T310 or T311 of the (NR / LTE) RRC protocol as known and defined in the 3GPP TS 38 series of specifications is running;

[0273] (b) if T301 of the (NR / LTE) RRC protocol as known and defined in the 3GPP TS TS 38 series of specifications is running;

[0274] (c) if T304 of the (NR / LTE) RRC protocol as known and defined in the 3GPP TS TS 38 series of specifications is running;

[0275] (d) When (part of) the sensing results for the SL resources (pools) configured to the UE are still not available.

[0276] (e) from the moment the UE initiates a (NR / LTE) RRC connection (reestablishment / resumption) until receipt of an RRC (connection) reconfiguration including a SL resource (pool) configuration, or until receipt of an RRC (connection) release (e.g., an RRC (connection) release message with / without abort configuration, which indicates that the UE moves to a (LTE / NR) RRC deactivated state) or an RRC (connection) reject message.

[0277] (f) If the UE is initiated to transmit PC5-RRC signaling (e.g., SL-SR procedure, SL-BSR procedure, or SL-PHR procedure) to other UEs via the PC5 interface, or when the UE remains in the SL-DRX off period, the UE is initiated to transmit the SL SR request procedure, BSR procedure, or SL PHR procedure to the UE's serving cell via the (LTE / NR) Uu interface.

[0278] In some embodiments, the SL-DRX off period may be terminated when (at least) the special conditions described above occur, and the UE may then wake up to transition to the next SL-DRX on duration (e.g., the UE may start the SL-drx-onDurationTimer after SL-drx-SlotOffset (≥0) at the start of the corresponding subframe in the associated (LTE / NR) PC5 interface).

[0279] Turning to SL reception, it may include SCI reception in PSCCH and SL packet delivery in PSSCH. In some embodiments, when the UE remains in the SL-DRX off period, the UE may not monitor the first stage SCI (or referred to as the first SCI) in the PSCCH and the following associated PSSCH from the available SL resources. The available SL resources may include all SL reception resource pools. In addition, when two-stage SCI is implemented on the PC5 interface, during the SL-DRX off period, the UE cannot monitor the second stage SCI (or referred to as the second SCI) that can be delivered on the PSSCH.

[0280] Note also that the SL reception resource pool may include one or more SL frequency carriers on which the UE may monitor SL packet reception.

[0281] It is worth noting that in some embodiments, a subset of the SL receive resource pool can be configured for the UE to monitor even during the SL-DRX off period. For example, a set of SL-DRX-Rx pool resource configurations can be configured to the UE (e.g., via SL pre-configuration; via dedicated control signaling in the Uu interface, such as RRC (connection) reconfiguration message; via dedicated signaling in the PC5 interface, such as PC5-RRC signaling; via broadcast messages, such as SI; via SI on-demand process). Then, after the UE moves to the SL-DRX off period, the UE can start monitoring the SL-DRX-Rx resource pool. Then, after the UE moves to the SL-DRX on duration in the next SL-DRX cycle, the UE can monitor the entire configured SL receive resource pool. Moreover, in some embodiments, the proposed SL-DRX-Rx resource pool configuration may also include a SL exception resource pool, which is configured for the SL-Tx UE to transmit SL packets when at least one of the above-mentioned exception conditions is met. It is also worth noting that, in some embodiments, the definition of the SL-DRX active time may only take into account the count of the SL-drx-onDurationTimer. In other words, after the SL-drx-onDurationTimer expires (and the (SL-DRX) active time in the PC5 interface has also ended), the UE may directly transition from the SL-DRX on duration to the SL-DRX off period. Then, within the SL-DRX cycle, the UE may apply different sets of SL receive resource pools within the SL-DRX on duration or the SL-DRX off period, respectively. It is also worth noting that, in some embodiments, the SL receive resource pools for the SL-DRX on duration and the SL-DRX off period may be independently configured and isolated in the PRB allocation. In some embodiments, the SL receive resource pools for the SL-DRX on duration and the SL-DRX off period may (partially) overlap with the PRB allocation.

[0282] Turning to the SL-Uu related mechanisms of the RAN, first, it may include SL dynamic grant monitoring. In some embodiments, when the UE remains in the SL-DRX off period, the UE may not monitor the PDCCH (or the search space / CORESET configured for SL dynamic grant reception (e.g., for SL dynamic grant reception). Therefore, the UE may not attempt to decode the PDCCH by using the RNTI configured for SL dynamic grant reception (e.g., SL-RNTI / sl-RNTI). In some embodiments, the UE can still monitor the PDCCH from the serving RAN during the (SL-DRX) active time of the Uu interface, even when the UE is maintaining the SL-DRX off period in the PC5 interface. In some embodiments, the UE may not monitor the PDCCH only when the UE remains in the SL-DRX off period and the C-DRX off period.

[0283] Second, the SL-Uu related mechanisms of the RAN may include grant activation / deactivation of SL (type 2) configuration. In some embodiments, when the UE remains in the SL-DRX off period, the UE may not monitor the PDCCH (for example, if the UE is configured with a grant of type 2 SL configuration, the UE may not monitor the PDCCH for grant activation / deactivation of SL configuration from the serving RAN). Thus, the UE may not attempt to decode the PDCCH by using the RNTI configured for activation / deactivation of the grant configured for SL configuration (for example, SL-CS-RNTI / sl-CS-RNTI). In some embodiments, even when the UE remains in the SL-DRX off period in the PC5 interface, the UE may still monitor the PDCCH (or the search space / CORESET configured for grant (de) activation of SL configuration) during the (SL-DRX) active time of the Uu interface (for example, for grant activation / deactivation of SL configuration from the serving RAN). In some embodiments, the UE may not monitor PDCCH / search space / CORESET (e.g., for grant activation / deactivation of SL configuration from the serving RAN) only when the UE remains in the SL-DRX off period and the C-DRX off period.

[0284] Third, the SL-Uu related mechanisms of the RAN may include SL-BSR (Uu interface) for SL packet transmission. In some embodiments, when the UE remains in the SL-DRX off period, the UE may not trigger (multiple) SL-SR processes for the SL LCH to the serving RAN (e.g., via the Uu interface). In some embodiments, even when the UE is maintaining a SL-DRX off period in the PC5 interface, the UE can still monitor the PDCCH from the serving RAN during the (SL-DRX) active time of the Uu interface. In some embodiments, when the UE remains in a C-DRX off period (and / or a SL-DRX off period), the UE may not initiate a SL SR to the UE's serving cell via the Uu interface. In some embodiments, during the SL-DRX off period, the UE may abort / stop / release / delete / remove all or a subset of ongoing SL-SR processes associated with the serving RAN on the (LTE / NR) Uu interface.

[0285] Fourth, the SL-Uu related mechanisms of the RAN may include SL-BSR (Uu interface) for SL packet transmission. In some embodiments, when the UE remains in the SL-DRX off period, the UE may not trigger the SL-BSR process to report the BSR of the SL LCH to the serving RAN. In some embodiments, even when the UE is remaining in the SL-DRX off period in the PC5 interface, the UE can still report the BSR of the SL LCH to the serving RAN during the (SL-DRX) active time of the Uu interface. In some embodiments, when the UE remains in the C-DRX off period (and / or the SL-DRX off period), the UE may not initiate a SL-BSR to the UE's serving cell through the Uu interface. In some embodiments, during the SL-DRX off period, the UE may abort / stop / release / delete / remove all or a subset of the ongoing SL-BSR processes associated with the serving RAN on the (LTE / NR) Uu interface.

[0286] Fifth, the SL-Uu related mechanisms of the RAN may include SL-PHR (Uu interface) for SL packet transmission. In some embodiments, when the UE is in the SL-DRX off period, the UE may not trigger the SL-PHR process to report the PHR to the serving RAN. In some embodiments, even if the UE is maintaining the SL-DRX off period in the PC5 interface, the UE can still trigger the SL-PHR process to the serving RAN during the (SL-DRX) active time of the Uu interface. In some embodiments, when the UE remains in the C-DRX off period (and / or the SL-DRX off period), the UE may not initiate the SLPHR to the serving cell of the UE through the Uu interface. In some additional embodiments, during the SL-DRX off period, the UE may abort / stop / release / delete / remove all or a subset of the ongoing SL-PHR processes associated with the serving RAN on the (LTE / NR) Uu interface.

[0287] Sixth, the SL-Uu related mechanisms of the RAN may include SL-HARQ feedback information in the Uu interface. In some embodiments, when the UE remains in the SL-DRX off period, the UE may not transmit SL-HARQ feedback information to the serving RAN. In some embodiments, even when the UE is remaining in the SL-DRX off period in the PC5 interface, the UE can still transmit SL-HARQ feedback to the serving RAN during the (SL-DRX) active time of the Uu interface. In some embodiments, when the UE remains in the C-DRX off period (SL-DRX off period), the UE may not transmit SL-HARQ feedback information to the serving RAN. In some embodiments, during the SL-DRX off period, the UE may suspend / stop / release / delete / remove all or a subset of the ongoing SL-HARQ feedback processes associated with the serving RAN on the (LTE / NR) Uu interface.

[0288] Turning to the SL synchronization mechanism, the SL synchronization mechanism may include SL synchronization sequence transmission. In some embodiments, the UE may become a SyncRef UE, which continuously broadcasts SL synchronization messages (e.g., SL synchronization sequence block groups (SL-SSB (SLSynchronization Sequence block) groups) and SL-MIB / SL-MIB-V2X). In some embodiments, when the UE remains in the SL-DRX off period, the UE may stop / suspend / postpone / stop / release / delete / remove the transmission of SL synchronization messages. Then, after the UE moves to the SL-DRX on duration again, the UE may continuously transmit SL synchronization messages. In some embodiments, the SyncRef UE may continue to broadcast the SL-SSB group and its associated SL-MIB / SL-MIB-V2X (e.g., via PSBCH) without being affected by the transition between the SL-DRX on duration and the SL-DRX off period.

[0289] Turning to the SL discovery mechanism, it may first include a SL discovery message transmission mechanism. In some embodiments, with respect to the (LTE / NR) SL discovery mechanism, the UE may be configured to transmit / receive SL discovery messages. The content of the SL discovery message may be provided by an upper layer (e.g., an application layer / V2X layer). The SL discovery message may be transmitted in a specific physical sidelink discovery CH (PSDCH: Physical Sidelink Discovery CH) or in a common PSSCH. In some embodiments, (e.g., for some commercial SL discovery services), the UE may stop transmitting SL discovery messages while the UE remains within the SL-DRX off period. Then, after the UE moves to the SL-DRX on duration (or SL-DRX active time) again, the UE may continuously retransmit the SL discovery message. In some embodiments, if the SL discovery message is for a specific service (e.g., for a public safety service), the UE may continue to transmit the SL discovery message without being affected by the switching / conversion between the SL-DRX on duration and the SL-DRX off period.

[0290] Second, SL discovery may include a SL discovery message receiving mechanism. In some embodiments (e.g., for some commercial SL discovery services), when the UE remains in the SL-DRX off period, the UE may stop / suspend / postpone / delete / remove / release monitoring of the SL discovery message. Then, after the UE moves to the SL-DRX on duration again, the UE may start continuously monitoring the SL discovery message again. In some embodiments, if the SL discovery message is for a specific service (e.g., for a public safety service), the UE may continue to monitor the SL discovery message without being affected by the switching / conversion between the SL-DRX on duration and the SL-DRX off period.

[0291] Counters / timers related to SL-DRX mechanism

[0292] In some implementations, more details of UE behavior may be included in the following cases:

[0293] UE behavior that triggers the UE to switch from SL-DRX off period to SL-DRX on duration;

[0294] UE behavior when the UE remains in SL-DRX on duration;

[0295] UE behavior that triggers the UE to switch from SL-DRX on duration (or SL-DRX active time) to SL-DRX off period;

[0296] • UE behavior during the UE remains in SL-DRX active time (for Uu interface and / or for PC5 interface).

[0297] Specifically, more detailed UE behavior during the SL-DRX on duration can be presented below. On the UE side, the RRC sublayer can control the SL-DRX operation by configuring the following parameters:

[0298] SL-drx-onDurationTimer: This can be the duration when the SL-DRX cycle starts;

[0299] SL-drx-SlotOffset: This can be the delay before starting the drx-onDurationTimer;

[0300] SL-drx-InactivityTimer: This may be the duration after a PSCCH opportunity where the PSCCH indicates a new SL transmission or reception for the concerned MAC entity;

[0301] drx-RetransmissionTimerSL_Rx (e.g., for each SL-HARQ reception process for which a UE needs to transmit SL-HARQ feedback information to an associated SL-Tx UE): this may be the maximum duration until a SL retransmission is received;

[0302] drx-RetransmissionTimerSL_Tx (e.g., each SL-HARQ transmission process where the UE needs to retransmit the SL MAC PDU based on the SL-HARQ feedback information replied by at least one SL-Rx UE): This may be the maximum duration until a grant for SL retransmission is received;

[0303] SL-drx-LongCycleStartOffset: This may be a long SL-DRX cycle and drx-StartOffset including the subframe defining where the long DRX cycle or short DRX cycle starts;

[0304] SL-drx-ShortCycle (optional): This can be a short SL-DRX cycle;

[0305] SL-drx-ShortCycleTimer (optional): This may be the duration that the UE may follow a short SL-DRX cycle;

[0306] drx-HARQ-RTT-TimerSL_Rx (e.g., for each SL-HARQ reception process for which the UE needs to transmit SL-HARQ feedback information to the associated SL-Tx UE): This may be the minimum duration before the MAC entity expects a SL allocation for SL-HARQ reception;

[0307] drx-HARQ-RTT-TimerSL_Tx (e.g., each SL-HARQ transmission process where the UE needs to retransmit the SL MAC PDU based on the SL-HARQ feedback information replied by at least one SL-Rx UE): This may be the minimum duration before the MAC entity expects a SL-HARQ retransmission grant.

[0308] In some embodiments, the UE may receive the configuration values ​​of the above parameters in the following ways: through SL pre-configuration; through dedicated control signaling in the (LTE / NR)Uu interface, such as RRC (connection) reconfiguration message; through dedicated signaling of the (LTE / NR)PC5 interface, such as PC5-RRC signaling; through broadcast messages, such as SI in the Uu interface (e.g., (NR / LTE)V2X-specific SIB); through the SI on-demand process of the Uu interface.

[0309] In some embodiments, when the SL-DRX cycle is configured in the PC5 interface, the (SL-DRX) active time in the PC5 interface may include the following times:

[0310] SL-drx-onDurationTimer, SL-drx-InactivityTimer, drx-RetransmissionTimerSL_Tx, or drx-RetransmissionTimerSL_Rx is running; or

[0311] The SR for SL dynamic grant request is sent on PUCCH (Uu interface) and is pending; or

[0312] The PSCCH indicates one (or more) new transmissions addressed to one of a set of MAC entities (associated SL source identity, interested SL destination identity) of at least one UE.

[0313] Considering the SL-drx-onDurationTimer, first, in some embodiments, it can be disclosed that when the UE wakes up at the beginning of the SL-DRX on-duration, the UE can start counting the SL-drx-onDurationTimer (e.g., after SL-drx-SlotOffset from the start of the subframe).

[0314] In some embodiments, considering the SL-drx-onDurationTimer again, it can be disclosed that if a (SL)DRX command MAC CE (or SL-DRX command) or a long DRX command MAC CE (or SL-long DRX command MAC CE) is received from the serving cell, the UE can stop counting the SL-drx-onDurationTimer. It is worth noting that in some embodiments, the UE can receive the (SL)DRX command MAC CE or SL-DRX command from the serving RAN via the (LTE / NR)Uu interface. In some embodiments, the UE can receive the DRX command MAC CE or SL-DRX command from other UEs (e.g., queue leaders or SL schedulers) via the (LTE / NR)PC5 interface. In some embodiments, the SL-DRX command or SL-long DRX command in the (LTE / NR)PC5 interface may be included in one or more PC5-RRC signaling or SCI between multiple UEs.

[0315] In some embodiments, considering the SL-drx-onDurationTimer again, if a long SL-DRX cycle is applied, the UE may start the SL-drx-onDurationTimer after the SL-drx-SlotOffset from the start of the subframe, and in the relevant (LTE / NR) PC5 interface, [(SFN×10)+subframe number] modulo(SL-drx-LongCycle)=SL-drx-StartOffset. It should also be noted that the subframe number may be associated with the subframe number obtained by the UE from the serving RAN via the (LTE / NR) Uu interface, or may be associated with the subframe number obtained by the UE from other UEs via the (LTE / NR) PC5 interface.

[0316] Secondly, SL-drx-InactivityTimer In some embodiments, if the MAC entity is in PC5 active time (or so-called SL-DRX active time), the UE can monitor PSCCH (continuously) for one or more SL frequency carriers. In some embodiments, the SL-DRX off period may also be referred to as the PC5 off period. Then, if a monitored PSCCH indicates a new SL packet transmission to the UE (or indicates SL control signaling) or the UE transmits SCI on the PSCCH, the UE can start or restart the SL-drx-InactivityTimer in the first symbol after the associated PSCCH ends.

[0317] In addition, for the UE side, the mechanism / operation can be described as follows:

[0318] 1> If SL-drx-InactivityTimer expires or a DRX command MAC CE (or SL-DRX command) is received:

[0319] 2> If the short SL-DRX cycle is configured as:

[0320] 3> After the SL-drx-InactivityTimer expires or in the first symbol or after the DRX command MAC CE (or SL-DRX command) is received, start or restart the SL-drx-ShortCycleTimer in the first symbol;

[0321] 3> Use a short SL-DRX cycle (also, the UE can switch from the SL-DRX on duration or the SL-DRX active time to the SL-DRX off period).

[0322] 2> Otherwise:

[0323] 3> Use a long SL-DRX cycle (also, the UE can switch from SL-DRX on duration or SL-DRX active time to SL-DRX off period).

[0324] Again, considering the SL-drx-InactivityTimer, in some embodiments, if a DRX command MAC CE (or SL-DRX command) or a long DRX command MAC CE (or SL-long DRX command MAC CE) is received from the serving cell, the UE can stop counting the SL-drx-InactivityTimer. It should also be noted that in some embodiments, the UE can receive a DRX command MAC CE or SL-DRX command from the serving RAN via the (LTE / NR) Uu interface. In some embodiments, the UE can receive a DRX command MAC CE or SL-DRX command from other UEs (e.g., a queue leader or SL scheduler) via the (LTE / NR) PC5 interface. In some embodiments, the SL-DRX command or SL-long DRX command in the (LTE / NR) PC5 interface may be included in one or more PC5-RRC signaling between multiple UEs.

[0325] Third, considering drx-HARQ-RTT-TimerSL_Rx and drx-RetransmissionTimerSL_Rx, in some embodiments, if the MAC entity is in the (SL-DRX) active time, the following operations / mechanisms may be configured to the UE side first:

[0326] 2>The UE can then (continuously) monitor the PSCCH of one (or more) SL frequency carriers;

[0327] 2> If a received PSCCH indicates SL transmission:

[0328] 3> The UE may start the drx-HARQ-RTT-TimerSL_Rx for the corresponding SL-HARQ process in the first symbol after the corresponding UE transmission carrying the SL-HARQ feedback ends (it should also be noted that in some embodiments, if the UE is not configured to send SL-HARQ feedback to the corresponding SL destination identifier, the UE may not start drx-HARQ-RTT-TimerSL_Rx);

[0329] 3>The UE may then stop the drx-RetransmissionTimerSL_Rx for the corresponding SL-HARQ process.

[0330] In some implementations, again considering drx-HARQ-RTT-TimerSL_Rx and drx-RetransmissionTimerSL_Rx, on the UE side, when SL-DRX is configured, the MAC entity may:

[0331] 1> If a SL MACPDU associated with the UE is received in the configured SL allocation (associated SL source identity, interested SL destination identity):

[0332] 2> (for example, if the UE is configured to transmit SL-HARQ feedback information about the corresponding SL-HARQ process associated with the corresponding destination identifier), the UE may start the drx-HARQ-RTT-TimerSL_Rx for the corresponding SL-HARQ process in the first symbol after the corresponding transmission carrying the SL-HARQ feedback ends;

[0333] 2>The UE may then stop the drx-RetransmissionTimerSL_Rx for the corresponding SL-HARQ process.

[0334] In some implementations, considering drx-HARQ-RTT-TimerSL_Rx, drx-RetransmissionTimerSL_Rx again, on the UE side, when SL-DRX is configured, the MAC entity may:

[0335] 1> If drx-HARQ-RTT-TimerSL_Rx expires and if the corresponding SL-

[0336] The data of the HARQ process was not decoded successfully:

[0337] 3>After the drx-HARQ-RTT-TimerSL_Rx expires, the UE may start the drx-RetransmissionTimerSL_Rx for the corresponding SL-HARQ process in the first symbol.

[0338] Fourth, considering drx-HARQ-RTT-TimerSL_Tx and drx-RetransmissionTimerSL_Tx, in some embodiments, if the SL MAC PDU is transmitted in the configured sidelink grant, the following operations / mechanisms may be configured to the UE side:

[0339] 2> After the transmission (or first repetition) of the corresponding PSSCH transmission ends, the UE may start the drx-HARQ-RTT-TimerSL_Tx for the corresponding SL-HARQ process in the first symbol;

[0340] 2>The UE may then stop the drx-RetransmissionTimerSL_Tx for the corresponding SL-HARQ process.

[0341] In some embodiments, considering drx-HARQ-RTT-TimerSL_Tx and drx-RetransmissionTimerSL_Tx again, at the UE side, if drx-HARQ-RTT-TimerSL_Tx expires, the following operations / mechanisms may be presented:

[0342] 2> After the drx-HARQ-RTT-TimerSL_Tx expires, the UE may start the drx-RetransmissionTimerSL_Tx for the corresponding SL-HARQ process in the first symbol.

[0343] In some embodiments, considering drx-HARQ-RTT-TimerSL_Tx and drx-RetransmissionTimerSL_Tx again, on the UE side, if the MAC entity is in (PC5) (SL-DRX) active time and if the UE transmits SCI indicating SL transmission on PSCCH, the following operations / mechanisms may be presented:

[0344] 3> After the first repetition of the corresponding PSSCH transmission ends, the UE may start the drx-HARQ-RTT-TimerSL_Tx for the corresponding SL-HARQ process in the first symbol; and

[0345] 3>The UE may then stop the drx-RetransmissionTimerSL_Tx for the corresponding SL-HARQ process.

[0346] Fifth, considering SL-drx-ShortCycle and SL-drx-ShortCycleTimer, in some embodiments, for a UE that remains in the SL-DRX on-duration, the following operations / mechanisms may be presented:

[0347] 1> If SL-drx-InactivityTimer expires or a DRX command MAC CE (or SL-DRX command) is received:

[0348] 2> If the short SL-DRX cycle is configured as:

[0349] 3> After the SL-drx-InactivityTimer expires or in the first symbol or after the DRX command MAC CE (or SL-DRX command) is received, the UE may start or restart the SL-drx-ShortCycleTimer in the first symbol;

[0350] 3>Then, the UE may use a short SL-DRX cycle (Note: and therefore the UE may move to a SL-DRX off period).

[0351] 2> Otherwise:

[0352] 3> Use long SL-DRX cycle (Note: and therefore the UE can move to SL-DRX off period).

[0353] 1> If SL-drx-ShortCycleTimer expires:

[0354] 2> Use a long SL-DRX cycle (Note: and therefore the UE can still be in the SL-DRX off period).

[0355] 1> If a long SL-DRX command (Long DRX Command MAC CE) is received:

[0356] 2>Stop SL-drx-ShortCycleTimer;

[0357] 2> Use long SL-DRX cycle (Note: and therefore the UE can move to SL-DRX off period).

[0358] In some embodiments, considering SL-drx-ShortCycle and SL-drx-ShortCycleTimer again, when the UE remains in the SL-DRX On Duration, the following operations / mechanisms may be present:

[0359] 1> if a short SL-DRX cycle is used, and [(SFN×10)+subframe number] modulo(SL-drx-ShortCycle)=(SL-drx-StartOffset) modulo(SL-drx-ShortCycle); or

[0360] 1> If a long SL-DRX cycle is used, and [(SFN×10)+subframe number] modulo(SL-drx-LongCycle)=SL-drx-StartOffset:

[0361] 2> Start SL-drx-onDurationTimer after SL-drx-SlotOffset from the start of the subframe (Note: and therefore the UE can move to SL-DRX On Duration).

[0362] In addition, in some embodiments, the UE may "wake up" in both the (LTE / NR) PC5 interface and the (LTE / NR) Uu interface at the same time (e.g., the UE may follow the C-DRX mechanism to decide whether to wake up in the Uu interface and the PC5 interface). In addition, in some embodiments, the UE may keep the (LTE / NR) PC5 interface in the (SL-DRX) active time during the (SL-DRX) active time in the associated (LTE / NR) Uu interface (e.g., drx-onDurationTimer or drx-InactivityTimer, or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL is running in the associated Uu interface). Thus, under certain conditions, the UE may:

[0363] When drx-onDurationTimer is started, start SL-drx-onDurationTimer (and vice versa).

[0364] When drx-InactivityTimer is started, SL-drx-InactivityTimer is started (and vice versa).

[0365] In addition, in some embodiments, the UE can switch / convert to the C-DRX off period and the SL-DRX off period in the PC5 interface and the Uu interface at the same time (for example, the UE can follow the C-DRX mechanism to decide whether to jointly convert to the C-DRX / SL-DRX off period in both the Uu interface and the PC5 interface).

[0366] The above embodiments discuss the UE behavior of implementing the SL-DRX mechanism. In some embodiments, the UE may transmit an indicator to the serving cell (e.g., through UE assistance information transmission or through a UE capability query process through the (LTE / NR) Uu interface) to indicate that the UE supports the SL-DRX mechanism or that the UE does not support the SL-DRX mechanism. In some embodiments, the default setting is that the UE (does not) support the SL-DRX mechanism. In addition, the UE's ability to support SL-DRX may be stored in the UE AS (deactivation) context on the UE side and the RAN side. In specific UE mobility events (e.g., (inter-RAT, intra-RAT or inter-system) handover process, MCG / SCG addition / change, RAN notification area update), the UE capability for supporting SL-DRX may be transmitted via an inter-node message (e.g., in a backhaul connection via an Xn interface or an X2 interface) as part of the UE AS (deactivation) context. In some embodiments, the UE may also report its ability to support (or not support) SL-DRX to other UEs via one or more PC5 interfaces (e.g., PC5-RRC signaling), which does not limit the scope of the embodiments.

[0367] Figure 6 FIG. 6 shows a SL packet exchange process 60 performed by a first UE according to an exemplary embodiment of the present disclosure. Figure 6 As shown, the SL packet exchange process 60 for the first UE includes the following actions:

[0368] Action 600: Start.

[0369] • Action 602: The first UE may receive a SL-DRX configuration indicating a SL-DRX function.

[0370] Action 604: The first UE may determine whether to monitor at least one of the first SCI on the PSCCH, the SL packet on the PSSCH, and the second SCI on the PSSCH according to the switching between the SL-DRX active time and the SL-DRX off period.

[0371] Action 606: End.

[0372] Preferably, actions 602 and 604 of the SL packet exchange process 60 can be configured for the first UE. Specifically, in some embodiments, the first UE can receive a SL-DRX configuration indicating a SL-DRX function in action 602. Next, in action 604, the first UE can determine whether to monitor at least one of the first SCI on the PSCCH (also referred to as the first stage SCI), the subsequent SL packet on the PSSCH, and the subsequent second SCI on the PSSCH (also referred to as the second stage SCI) according to the switching between the SL-DRX active time (or SL-DRX on duration) and the SL-DRX off period, wherein the SCI can come from at least one second UE. Both the SL-DRX active time (or SL-DRX on duration) and the SL-DRX off period can be determined by the SL-DRX function, and the SL transmission can be transmitted through a PC5 interface controlled by NR technology or LTE technology. In some embodiments, the first UE can be associated with the second UE in one of the SL unicast group, the SL multicast group, and the SL broadcast group. In some embodiments, the SL unicast group, SL multicast group, or SL broadcast group may be within the coverage of at least one service cell in a service RAN, within a partial coverage of at least one cell in a service RAN, or outside the coverage of a service RAN.

[0373] In some embodiments, the SL packet exchange process 60 may also configure the first UE to determine whether to transmit at least one of the first SCI (or first-stage SCI) on the PSCCH and the second SCI (or second-stage SCI) / SL packet on the subsequent PSSCH based on the switching between the SL-DRX active time (or SL-DRX on duration) and the SL-DRX off period. In some embodiments, the SL packet exchange process 60 may also configure the first UE to determine whether to transmit at least one SL-BSR to the first service cell for SL resource request or to monitor at least one DCI to the second service cell for SL resource configuration based on the switching between the SL-DRX active time (or SL-DRX on duration) and the SL-DRX off period by the first UE, wherein the first service cell may be an NR cell of the NR Uu interface or an E-UTRA cell in the E-UTRA Uu interface. In some embodiments, the SL packet exchange process 60 can also configure the first UE to determine whether to trigger at least one of the SL-SR process, SL-BSR process and SL-PHR process to at least one second UE on the PC5 interface based on the switching between the SL-DRX active time (or SL-DRX on duration) and the SL-DRXSL-DRX off period.

[0374] In some embodiments, a first UE may be configured with different SL resource pool configurations within a SL-DRX on duration, a SL-DRX active time, or a SL-DRX off period for SL packet exchange operations with at least one second UE, wherein the SL resource pool configuration may include a SL transmission resource pool configuration, a SL reception resource pool configuration, an exception resource pool configuration, a SL resource pool configuration for SL discovery message transmission, a SL dynamic authorization (i.e., one or more SL dynamic authorizations), a type 1 SL configuration authorization (i.e., one or more type 1Sl configuration authorizations), a type 2 SL configuration authorization (i.e., one or more type 2 SL configuration authorizations), and at least one of a SL synchronization signal burst set (i.e., one or more SL synchronization signal burst sets), and the SL resource pool configuration may be between the NR PC5 interface and the E-UTRA PC5 interface. In some embodiments, the first UE may be configured to switch between the SL-DRX active time (or SL-DRX on duration) and the SL-DRX off period based on at least one of SL-drx-onDurationTimer, SL-DRX-SlotOffset, SL-DRX-InactivityTimer, DRX-RetransmissionTimerSL (e.g., including drx-RetransmissionTimerSL_Rx and / or drx-RetransmissionTimerSL_Tx), SL-DRX-LongCycleStartOffset, SL-DRX-ShortCycle, SL-drx-ShortCycleTimer, and DRX-HARQ-RTT-TimerSL (e.g., drx-HARQ-RTT-TimerSL_Rx and / or drx-HARQ-RTT-TimerSL_Tx).

[0375] In some embodiments, the first UE may be configured to receive the SL-DRX configuration through at least one of SL pre-configuration, PC5-RRC signaling of another paired UE, broadcast SI of the serving cell in the Uu interface, and UE-specific DL RRC signaling in the Uu interface. In some embodiments, the first UE may be configured to perform CBR measurement and sensing mechanisms according to different SL resource pool configurations within the SL-DRX active time (or SL-DRX on duration) or the SL-DRX off period. Note that the first UE and the second UE may be merely depicted as exemplary embodiments to form two different devices / apparatuses for exchanging (one or more) SL packets, and the SL packet exchange process 60 may also be configured to the second UE for all of the above operations / mechanisms for exchanging (one or more) SL packets with the first UE, which does not limit the scope of the embodiments.

[0376] Reference Figure 7 , Figure 7 1 is a block diagram of a node 700 for wireless communication according to an exemplary embodiment of the present disclosure. Figure 7 As shown, the node 700 may include a transceiver 706, a processor 708, a memory 702, one or more presentation components 704, and at least one antenna 710. The node 700 may also include a radio frequency (RF) spectrum band module, a base station communication module, a NW communication module, a system communication management module, an input / output (I / O) port, an I / O component, and a power supply (in Figure 7 Each of these components may communicate with each other directly or indirectly via one or more buses 724. In one embodiment, the node 700 may be a UE or a BS that performs various functions disclosed herein, for example, Figure 1-6 .

[0377] The transceiver 706, which may have a transmitter 716 (e.g., a transmitting / transmission circuit) and a receiver 718 (e.g., a receiving / reception circuit), may be configured to transmit and / or receive time and / or frequency resource partitioning information. In one embodiment, the transceiver 706 may be configured to transmit in different types of subframes and time slots, including but not limited to usable, unusable, and flexibly usable subframe and time slot formats. The transceiver 706 may be configured to receive data and control channels.

[0378] Node 700 may include a variety of computer-readable media. Computer-readable media may be any available media that can be accessed by node 700, and include both volatile (and non-volatile) media, removable (and non-removable) media. By way of example and not limitation, computer-readable media may include computer storage media and communication media. Computer storage media include both volatile (and non-volatile) and removable (and non-removable) media, and may be implemented in any method or technology to store information such as computer-readable.

[0379] Computer storage media include RAM, ROM, EEPROM, flash memory (or other storage technology), CD-ROM, Digital Versatile Disk (DVD) (or other optical disk storage device), cassette, magnetic tape, magnetic disk storage (or other magnetic storage device), etc. Computer storage media do not include propagating data signals. Communication media may typically contain computer readable instructions, data structures, program modules or other data in a modulated data signal (such as a carrier wave or other transport mechanism), and include any information transmission media. The term "modulated data signal" may refer to a signal having one or more characteristics set or changed in a manner that encodes information in the signal. By way of example and not limitation, communication media include wired media (such as a wired NW or a direct wired connection) and wireless media (such as acoustic, RF, infrared and other wireless media). Any combination disclosed above should also be included in the scope of computer readable media.

[0380] The memory 702 may include computer storage media in the form of volatile and / or non-volatile memory. The memory 702 may be removable, non-removable, or a combination thereof. For example, the memory 702 may include solid-state memory, a hard drive, an optical drive, etc. Figure 7 As shown, the memory 702 may store a computer executable (readable) program 714 (eg, software code) configured to cause the processor 708 to perform various functions disclosed herein when executed, for example, referring to Figure 6 Alternatively, the computer executable program 714 may not be directly executable by the processor 708, but may be configured to cause the node 700 (eg, when compiled and executed) to perform various functions disclosed herein.

[0381] The processor 708 (e.g., having a processing circuit) may include an intelligent hardware device, such as a central processing unit (CPU), a microcontroller, an ASIC, etc. The processor 708 may include a memory. The processor 708 may process data 712 and a computer executable program 714 received from the memory 702, as well as information passed through the transceiver 706, the baseband communication module, and / or the NW communication module. The processor 708 may also process information to be sent to the transceiver 706 for transmission through the antenna 710, and information to be sent to the NW communication module for transmission to the CN.

[0382] One or more presentation components 704 can present data indications to a person or other device. Examples of presentation components 704 can include a display device, a speaker, a printing component, a vibration component, and the like.

[0383] As can be seen from the previous disclosure, various techniques can be used to implement these concepts without departing from the scope of the concepts described in this disclosure. In addition, although the concepts have been disclosed with specific reference to certain embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the scope of these concepts. Therefore, the disclosed embodiments should be considered illustrative and not restrictive in all respects. It should also be understood that the application is not limited to specific disclosed embodiments. Rather, many rearrangements, modifications and substitutions are possible without departing from the scope of this disclosure.

Claims

1. A method for sidelink SL packet switching operation performed by a first user equipment UE, characterized in that: The method comprises: receiving at least one SL-discontinuous reception (SL-DRX) configuration and a plurality of SL resource pool configurations to be configured on the first UE, and receiving indication information associated with a first SL resource pool configuration in the plurality of SL resource pool configurations; When the SL-DRX operation is performed based on the at least one SL-DRX configuration, performing partial sensing based on at least one SL resource pool configuration among the plurality of SL resource pool configurations, and performing SL-CBR measurement associated with each of the at least one SL resource pool; The indication information is used to indicate whether the first UE is capable of performing the partial sensing on the SL resource pool configured by the first SL resource pool configuration during the SL sensing window of at least one SL-DRX off period.

2. The method according to claim 1, characterized in that: The method further comprises: If the indication information indicates that the first UE is capable of performing the partial sensing, performing the partial sensing on the SL resource pool configured by the first SL resource pool configuration during the SL sensing window of the at least one SL-DRX off period, wherein, The at least one SL-DRX off period is determined based on a time period in which the first UE does not remain in a SL-DRX active time.

3. The method according to claim 2, characterized in that The method further comprises: Switching is performed between the SL-DRX active time and the at least one SL-DRX off period according to at least one of SL-DRX-onDurationTimer, SL-DRX-SlotOffset, SL-DRX-InactivityTimer, DRX-RetransmissionTimerSL, SL-DRX-LongCycleStartOffset, SL-DRX-ShortCycle, SL-DRX-ShortCycleTimer or DRX-HARQ-RTT-TimerSL.

4. The method according to claim 1, characterized in that: The method further comprises: If the indication information indicates that the first UE is prohibited from performing the partial sensing, then during the SL sensing window of the at least one SL-DRX off period, it is prohibited to perform the partial sensing on the SL resource pool configured by the first SL resource pool configuration, wherein, The at least one SL-DRX off period is determined based on a time period in which the first UE does not remain in a SL-DRX active time.

5. The method according to claim 1, characterized in that The first SL resource pool configuration associated with the indication information includes one of a SL normal transmission resource pool configuration or a SL exception resource pool configuration.

6. The method according to claim 1, characterized in that Receiving the first SL resource pool configuration associated with the indication information via at least one of the following: broadcast system information SI of a serving cell of the first UE from a cellular communication Uu interface, UE-specific Radio Resource Control (RRC) signaling from the serving cell of the first UE in the Uu interface, Control signaling from a second UE in the direct communication PC5 interface, the second UE being paired with the first UE in one of the SL unicast group, SL multicast group or broadcast group, or SL pre-configuration, the SL pre-configuration is pre-installed on the first UE; and The at least one SL-DRX configuration is received via at least one of: The SL is pre-configured, the control signaling from the second UE, the broadcast SI of the serving cell of the first UE in the Uu interface, or The UE-specific RRC signaling of the serving cell of the first UE in the Uu interface, wherein: The serving cell is an Evolved Universal Terrestrial Radio Access (E-UTRA) cell or a New Radio (NR) cell, The UE-specific RRC signaling is E-UTRA RRC signaling or NR RRC signaling, and The Uu interface is a NR Uu interface or an E-UTRA Uu interface.

7. The method according to claim 1, characterized in that The method further comprises: The plurality of SL resource pool configurations are received from one or more cells operating on one or more SL frequency carriers.

8. The method according to claim 1, characterized in that: Performing the partial sensing based on the at least one SL resource pool configuration among the plurality of SL resource pool configurations includes: monitoring at least one of the first side link control information SCI on the physical side link control channel PSCCH, the SL packet on the physical side link shared channel PSSCH, or the second SCI on the PSSCH, in: The PSCCH and the PSSCH are associated with a SL resource pool configuration in the at least one SL resource pool configuration, and The first SCI and the second SCI are from at least one second UE.

9. The method according to claim 1, characterized in that: The multiple SL resource pool configurations include at least one of the following: SL resource pool configuration for LTE-V2X SL communication services, SL resource pool configuration for LTE-V2X SL discovery service, SL resource pool configuration for NR SL communication services, SL resource pool configuration for NR SL discovery service, SL resource pool configuration for ProSe discovery service, or SL resource pool configuration for ProSe communication service.

10. A user equipment UE for sidelink SL packet switching operation in a wireless communication system, wherein the UE is a first UE, and the wireless communication system includes a base station BS, characterized in that: The UE includes: one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor configured to execute the computer-executable instructions to cause the UE to: receiving at least one SL-discontinuous reception (SL-DRX) configuration and a plurality of SL resource pool configurations to be configured on the first UE, and receiving indication information associated with a first SL resource pool configuration in the plurality of SL resource pool configurations; When the SL-DRX operation is performed based on the at least one SL-DRX configuration, performing partial sensing based on at least one SL resource pool configuration among the plurality of SL resource pool configurations, and performing SL-CBR measurement associated with each of the at least one SL resource pool; The indication information is used to indicate whether the first UE is capable of performing the partial sensing on the SL resource pool configured by the first SL resource pool configuration during the SL sensing window of at least one SL-DRX off period.

11. The UE according to claim 10, characterized in that: The at least one processor is further configured to execute the computer-executable instructions to cause the UE to: If the indication information indicates that the first UE is capable of performing the partial sensing, performing the partial sensing on the SL resource pool configured by the first SL resource pool configuration during the SL sensing window of the at least one SL-DRX off period, wherein, The at least one SL-DRX off period is determined based on a time period in which the first UE does not remain in a SL-DRX active time.

12. The UE according to claim 11, characterized in that: The at least one processor is further configured to execute the computer-executable instructions to cause the UE to: Switching is performed between the SL-DRX active time and the at least one SL-DRX off period according to at least one of SL-DRX-onDurationTimer, SL-DRX-SlotOffset, SL-DRX-InactivityTimer, DRX-RetransmissionTimerSL, SL-DRX-LongCycleStartOffset, SL-DRX-ShortCycle, SL-DRX-ShortCycleTimer or DRX-HARQ-RTT-TimerSL.

13. The UE according to claim 10, characterized in that: The at least one processor is further configured to execute the computer-executable instructions to cause the UE to: If the indication information indicates that the first UE is prohibited from performing the partial sensing, then during the SL sensing window of the at least one SL-DRX off period, it is prohibited to perform the partial sensing on the SL resource pool configured by the first SL resource pool configuration, wherein, The at least one SL-DRX off period is determined based on a time period in which the first UE does not remain in a SL-DRX active time.

14. The UE according to claim 10, characterized in that: The first SL resource pool configuration associated with the indication information includes one of a SL normal transmission resource pool configuration or a SL exception resource pool configuration.

15. The UE according to claim 10, characterized in that: Receiving the first SL resource pool configuration associated with the indication information via at least one of the following: broadcast system information SI of a serving cell of the first UE from a cellular communication Uu interface, UE-specific Radio Resource Control (RRC) signaling from the serving cell of the first UE in the Uu interface, Control signaling from a second UE in the direct communication PC5 interface, the second UE being paired with the first UE in one of the SL unicast group, SL multicast group or broadcast group, or SL pre-configuration, the SL pre-configuration is pre-installed on the first UE; and The at least one SL-DRX configuration is received via at least one of: The SL is pre-configured, the control signaling from the second UE, the broadcast SI of the serving cell of the first UE in the Uu interface, or The UE-specific RRC signaling of the serving cell of the first UE in the Uu interface, wherein: The serving cell is an Evolved Universal Terrestrial Radio Access (E-UTRA) cell or a New Radio (NR) cell, The UE-specific RRC signaling is E-UTRA RRC signaling or NR RRC signaling, and The Uu interface is a NR Uu interface or an E-UTRA Uu interface.

16. The UE according to claim 10, characterized in that: The at least one processor is further configured to execute the computer-executable instructions to cause the UE to: The plurality of SL resource pool configurations are received from one or more cells operating on one or more SL frequency carriers.

17. The UE according to claim 10, characterized in that: Performing the partial sensing based on the at least one SL resource pool configuration among the plurality of SL resource pool configurations includes: monitoring at least one of the first side link control information SCI on the physical side link control channel PSCCH, the SL packet on the physical side link shared channel PSSCH, or the second SCI on the PSSCH, in: The PSCCH and the PSSCH are associated with a SL resource pool configuration in the at least one SL resource pool configuration, and The first SCI and the second SCI are from at least one second UE.

18. The UE according to claim 10, characterized in that: The multiple SL resource pool configurations include at least one of the following: SL resource pool configuration for LTE-V2X SL communication services, SL resource pool configuration for LTE-V2X SL discovery service, SL resource pool configuration for NR SL communication services, SL resource pool configuration for NR SL discovery service, SL resource pool configuration for ProSe discovery service, or SL resource pool configuration for ProSe communication service.

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