WO2025015467A1

WO2025015467A1 - Devices and methods for sidelink communication

Info

Publication number: WO2025015467A1
Application number: PCT/CN2023/107567
Authority: WO
Inventors: Rao SHI; You Li; Zhaobang MIAO; Ying Zhao; Gang Wang
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2023-07-14
Filing date: 2023-07-14
Publication date: 2025-01-23
Anticipated expiration: 2026-01-14

Abstract

Embodiments of the present disclosure provide a solution for sidelink communication. In a solution, a terminal device determines Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and performs a LBT failure cancellation at least based on the LBT failure information.

Description

DEVICES AND METHODS FOR SIDELINK COMMUNICATION

FIELDS

Example embodiments of the present disclosure generally relate to the field of communication techniques and in particular, to devices and methods for sidelink (SL) communication.

BACKGROUND

With the development of communication techniques, a variety of communication networks have been developed or studied. In some wireless communication networks, in addition to communicating with base stations via access links, user equipment (UE) can communicate with other devices using a sidelink (e.g., a communication link between a UE and another UE) as well. Such communication may relate to, for example, vehicle-based communication devices that can communicate from vehicle-to-vehicle (V2V) , vehicle-to-infrastructure (V2I) (e.g., from the vehicle-based communication device to road infrastructure nodes) , vehicle-to-network (V2N) (e.g., from the vehicle-based communication device to one or more network nodes, such as a base station) , a combination thereof and/or with other devices, which can be collectively referred to as vehicle-to-anything (V2X) communications. Further improvements related to the sidelink communication are desired.

SUMMARY

In a first aspect, there is provided a terminal device. The terminal device comprises: a processor configured to cause the terminal device to: determine Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and perform a LBT failure cancellation at least based on the LBT failure information.

In a second aspect, there is provided a terminal device. The terminal device comprises: a processor configured to cause the terminal device to: detect a Listen Before Talk (LBT) failure for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions; and in accordance with a determination that the LBT failure is detected, transmit information associated with the LBT failure to a network device based on a connection state of the terminal device with the network device.

In a third aspect, there is provided a network device. The network device comprises: a processor configured to cause the network device to: receive, from a terminal device, information associated with a Listen Before Talk (LBT) failure based on a connection state of the terminal device with the network device, and wherein the LBT failure is detected for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions.

In a fourth aspect, there is provided a first terminal device. The first terminal device comprises: a processor configured to cause the first terminal device to: perform packet transmissions with a second terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and in accordance with a determination that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended, transmit, to the second terminal device, information indicating the at least one suspended transmission.

In a fifth aspect, there is provided a second terminal device. The second terminal device comprises: a processor configured to cause the second terminal device to: perform packet transmissions with a first terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and receive, from the first terminal device, information indicating that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended.

In a sixth aspect, there is provided a communication method performed by a terminal device. The method comprises: determining Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and performing a LBT failure cancellation at least based on the LBT failure information.

In a seventh aspect, there is provided a communication method performed by a terminal device. The method comprises: detecting a Listen Before Talk (LBT) failure for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions; and in accordance with a determination that the LBT failure is detected, transmitting information associated with the LBT failure to a network device based on a connection state of the terminal device with the netw ork device.

In an eighth aspect, there is provided a communication method implemented at a network device, comprising: receiving, from a terminal device, information associated with a Listen Before Talk (LBT) failure based on a connection state of the terminal device with the network device, and wherein the LBT failure is detected for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions.

In a ninth aspect, there is provided a communication method performed by a first terminal device. The method comprises: performing packet transmissions with a second terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and in accordance with a determination that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended, transmitting, to the second terminal device, information indicating the at least one suspended transmission.

In a tenth aspect, there is provided a communication method performed by a second terminal device. The method comprises: performing packet transmissions with a first terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and receiving, from the first terminal device, information indicating that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended.

In an eleventh, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to the sixth, seventh, eighth, ninth or tenth aspect.

Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some example embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

FIG. 2 illustrates a signaling flow of LBT failure cancellation in accordance with some embodiments of the present disclosure;

FIG. 3 illustrates a signaling flow of LBT failure report in accordance with some embodiments of the present disclosure;

FIG. 4A illustrates a schematic diagram of an example for configured resources and resources for synchronization signal block (SSB) transmission;

FIG. 4B illustrates a schematic diagram of another example for configured resources and resources for SSB transmission;

FIG. 5 illustrates a signaling flow of packet transmission suspending in accordance with some embodiments of the present disclosure;

FIG. 6 illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

FIG. 7A illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

FIG. 7B illustrates a flowchart of a method implemented at a network device according to some example embodiments of the present disclosure;

FIG. 8 illustrates a flowchart of a method implemented at a first terminal device according to some example embodiments of the present disclosure;

FIG. 9 illustrates a flowchart of a method implemented at a second terminal device according to some example embodiments of the present disclosure;

FIG. 10 illustrates a simplified block diagram of an apparatus that is suitable for implementing example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, devices on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types of realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST) , or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporate one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

The term “network device” refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , and the like.

The terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal or the network device may work on several frequency ranges, e.g., FR1 (e.g., 450 MHz to 6000 MHz) , FR2 (e.g., 24.25GHz to 52.6GHz) , frequency band larger than 100 GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connection with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The embodiments of the present disclosure may be performed in test equipment, e.g., signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator. In some embodiments, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs) . In some embodiments, the first network device may be a first RAT device and the second network device may be a second RAT device. In some embodiments, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device. In some embodiments, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In some embodiments, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

As used herein, the singular forms ‘a’ , ‘an’ and ‘the’ are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’ The term ‘based on’is to be read as ‘at least in part based on. ’ The term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment. ’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’ The terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as ‘best, ’ ‘lowest, ’ ‘highest, ’ ‘minimum, ’ ‘maximum, ’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

As used herein, the term “resource, ” “transmission resource, ” “uplink resource, ” or “downlink resource” may refer to any resource for performing a communication, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

As used herein, a resource block (RB) set in a resource pool may comprise a certain number of resource blocks. RB sets with different numbers of RBs may be defined for different resource pools. An RB set may also be referred to as a frequency unit, a frequency band, or a sub-band, or a channel. In some cases, there may be a gap of guard band between two contiguous RB sets in a resource pool.

As used herein, the term “packet” may refer to a protocol data unit (PDU) , one or more PDUs, a service data unit (SDU) , one or more SDUs, a PDU set, etc. In the following, some embodiments may be described with respect to the PDU or PDU set. However, this is example without limitation.

FIG. 1 illustrates a schematic diagram of an example communication environment 100 in which example embodiments of the present disclosure can be implemented. In the communication environment 100, a plurality of communication devices, including a network device 120, and two or more terminal devices 110-1, 110-2, …, 110-N (where N is an integer larger than one) , can communicate with each other. In the following, the two or more terminal devices 110-1, 110-2, …, 110-N may be referred to as the terminal device 110 individually or terminal devices 110 collectively.

In the example of FIG. 1, the two or more terminal devices 110 may be UEs. The network device 120 may be a base station serving the UEs, for example, a gNB.

It is to be understood that the number of devices and their connections shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The communication environment 100 may include any suitable number of devices configured to implementing example embodiments of the present disclosure.

In the following, for the purpose of illustration, some example embodiments are described with the terminal devices 110 operating as UEs and the network device 120 operating as a base station. However, in some example embodiments, operations described in connection with a terminal device may be implemented at a network device or other device, and operations described in connection with a network device may be implemented at a terminal device or other device.

The communications in the communication environment 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , New Radio (NR) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

In some example embodiments, the network device 120 may communicate with the terminal devices 110. A link from the network device 120 to a terminal device 110 is referred to as a downlink (DL) , while a link from the terminal device 110 to the network device 120 is referred to as an uplink (UL) . In DL, the network device 120 is a transmitting (TX) device (or a transmitter) and the terminal device 110 is a receiving (RX) device (or a receiver) . In UL, the terminal device 110 is a TX device (or a transmitter) and the network device 120 is a RX device (or a receiver) .

The terminal devices 110 can communicate with each other over a sidelink. The communication between the terminal devices 110 over the sidelink may be referred to as sidelink communication. There may be different modes for allocating the resource for the sidelink communication, which are referred to as resource allocation (RA) modes.

The RA modes may include a first mode and a second mode which are different from each other in SL resource allocation. In some example embodiments, the first mode may be the mode 1, which is also referred to as a network scheduled resource allocation scheme. In mode 1, the resource for the sidelink communication is scheduled by the network device 120. For example, in mode 1, the network device 120 may configure the terminal device 110 with a resource pool for sidelink data transmission and/or sidelink control information transmission.

As an example but without any limitation, in mode 1, the network device 120 may schedule the terminal device 110 to perform SL transmission, and there may be a dedicated resource pool for resource scheme in mode 1. The network device 120 may perform resource allocation for physical sidelink control channel (PSCCH) and/or physical sidelink shared channel (PSSCH) , and dynamic scheduling and configured grant (which is semi-persistent scheduling (SPS) and shorted as CG) may be supported. There are two types of CG which are type 1 CG and type 2 CG. Dynamic scheduling is based on downlink control information (DCI) . Type 1 CG is based on radio resource control (RRC) configuration. Type 2 CG is based on RRC configuration and activated by DCI. Scheduling more than one resources for a TB for initial transmission and retransmission (s) is supported. The network device 120 does not receive SL signals.

The terminal device 110 in SL communication may transmit sidelink control information (SCI) /data on the scheduled PSCCH/PSSCH resources. The RRC connection (for example, a Uu connection) is made between the terminal device and the network device 120. Dedicated radio network temporary identification (RNTI) for SL scheduling DCI is different from Uu RNTI. SL Acknowledge (ACK) /Negative Acknowledge (NACK) may be forwarded to the network device 120 on physical uplink control channel (PUCCH) and/or physical uplink shared channel (PUSCH) according to configuration.

The second mode may be mode 2, which may be also referred to as an autonomously resource selection scheme. In mode 2, the resource for the sidelink communication is selected by the terminal device 110.

As an example but without any limitation, in mode 2, the terminal device 110 may select SL resources to perform SL transmission. Mode 2 may include a full sensing scheme, a partial sensing scheme, and a random selection scheme. In the full sensing scheme, initial candidate resources are firstly set as a full set, and then unavailable resources are excluded from the candidate resource set. At last, the final candidate resource set is determined. In some embodiments, inter-UE coordination (IUC) may be used when IUC is (pre-) configured and triggered. If the IUC is triggered, the preferred resource set may be determined for other terminal device’s transmission or the non-preferred resource set from other terminal device (s) may be excluded.

Some mechanism regarding the mode 1 and mode 2 are described. It is to be understood that the mode 1 and mode 2 are given as examples without any limitation, and other RA modes are possible.

In some embodiments, CA may be adopted for the sidelink communication. At least one of the terminal devices 110 may be capable of CA. CA and its architecture have been studied for SL enhancement. To better understand the solution of the present disclosure, some solutions regarding CA in SL communication (also referred to as SL CA for short) are now described.

It is supported that one independent Hybrid Automatic Repeat reQuest (HARQ) entity per carrier used for SL communication in NR and one transport block is generated per carrier. It is supported that each transport block and its retransmissions are mapped to a same single carrier. For groupcast (GC) or broadcast (BC) , as in LTE SL CA, the carrier (s) that can be used for transmitting data are configured by V2X layer for the layer-2 (L2) destination. Backwards compatibility issues are for further study.

Packet duplication for NR SL is performed at the PDCP layer. The duplicated PDCP packet data units (PDUs) of the same PDCP entity are submitted to two different radio link control (RLC) entities and associated to two different SL logical channels respectively. It is agreed that logical channel (LCH) mapping restriction shall be defined such that the duplicated PDCP PDUs of the same PDCP entity are only allowed to be transmitted on different NR SL carriers.

For PDCP duplication in NR SL communication, the hard-coded way for paired SL logical channel ID (LCID) is re-used to identify duplicated SL LCHs (for example, for a unified design for all GC/BC) . For TX carrier (re) selection triggers in NR SL CA, if the resource (re) selection is triggered with the SL process or if there is no SL grant associated with the SL process on any carrier allowed for the STCH as indicated by upper layers (for example, RRC layer and V2X layer) , the triggers for TX carrier (re) selection per SL process in LTE SL CA may be re-used at least for GC/BC.

For link control protocol (LCP) , the LCHs having a priority whose associated channel busy ratio (CBR) threshold for reselection is only allowed to be no lower than the CBR of the carrier when the carrier is selected or reselected. The way to determine the per-carrier CBR at least for GC/BC is for further study.

TX carrier (re) selection in NR SL CA follows LTE CA solution, for example per-carrier-per-priority CBR threshold for carrier (re) selection and per-carrier-per-priority CBR threshold for carrier keeping are defined. Final carrier selection is made based on the lowest CBR value across carriers and the priority is the LCH priority.

Based on an observation that V2X layer can be provisioned with service to frequency mapping for unicast, it is assumed that it is applicable to PC5 unicast SL CA after link has been established. V2X layer is only provisioned with a mapping between a service identifier and an initial L2 address used for unicast, however the service identifier is invisible to Access Stratum (AS) -layer, and the initial L2 identity (ID) will only be used in Direct Communicate Request (DCR) message and be replaced by a chosen L2 ID in PC5-signalling (PC5-S) link establishment procedure. Then, after L2 ID changes, whether/how AS-layer of UE can obtain the mapping between L2 ID and frequencies is to be determined. PC5 unicast allows UEs to add/modify/remove V2X services/PC5 quality of service (QoS) flows to the same L2 ID pair. Then, given service information is invisible to AS layer, how can the UE ensure the modified V2X services to be transmitted only on the corresponding frequencies in the V2X layer needs to be specified.

Some cases on backward compatibility issue in SL CA for GC/BC are considered, for example a case that a V2X service needs to be mapped into multiple carriers while there is at least one legacy UE to receive this V2X service. The solution of per carrier CBR is same as LTE V2X CA is applied. Regarding TX carrier (re) selection triggers, LCP impact, and CBR-based carrier reselection/keeping for uplink control (UC) , solutions for GC/BC may be also applicable for UC. TX carrier reselection is done among the carriers that peer UE also supports. Regarding LCID to identify duplicated SL LCHs, solutions for GC/BC may be also applicable for UC. Regarding the criterion for packet duplication, SLRB configures whether PDCP duplication is used or not. Regarding discontinuous transmission (DTX) based SL radio link failure (RLF) in SL CA, the counting is calculated per carrier and legacy SL RLF is not declared when the counting is reached to sl-MaxnumConsecutiveDTX for carrier (s) and the UE has other available SL carrier (s) for SL CA. Regarding PDCP duplication/SL CA for SL SRB, it is assumed that SL CA/PDCP duplication is applied to PC5-RRC after SL link is established.

In some embodiments, LBT may be performed for sidelink communication, for example, in the case of SL in unlicensed spectrum (SL-U) . To better understand the solution of the present disclosure, some solutions regarding LBT for sidelink are now described. If an LBT failure is detected by a physical layer of the terminal device 110, the physical layer may indicate a medium access control (MAC) entity of the terminal device 110 of the LBT failure. The MAC entity may count the number of LBT failure indications from the physical layer. If the number of LBT failure indications reaches a threshold number, a consistent LBT (C-LBT) failure may be detected or declared. The SL C-LBT may be declared per RB set.

Regarding C-LBT failure handling and/or recovery, the terminal device 110 may use the MAC control element (CE) to report consistent LBT failure to the network device 120. An Uu MAC CE may indicate RB set (s) where the C-LBT failure happens. The terminal device 110 may trigger SL RLF for all UC connections when the terminal device 110 has triggered consistent SL LBT failure in all RB sets. The term “Uu MAC CE” refers to MAC CE transmitted via the Uu interface from a terminal device to a network device.

Regarding channel occupancy time (COT) sharing and LCP enhancement, if the resource to be used is within a shared COT, and if PDU is not generated before COT arrival, and there is data in buffer satisfying COT requirement, at least enhanced LCP may be allowed. If the terminal device 110 decides to use the resource in a shared COT, and when enhanced LCP is decided to be used, for destination selection step in enhanced LCP, at least the destinations may be further restricted to be the candidates allowed by the COT.

Regarding CG retransmission timer, CG retransmission timer in SL-U may not be supported. Regarding SL Best-match decision for per-flow channel access priority class (CAPC) , for ‘best-match’ issue, the terminal device 110 may determine it based on closest packet Delay Budget (PDB) .

Regarding SL C-LBT failure recovery in mode 2 for RRC ide/inactive terminal device, RB set (s) that SL C-LBT failure was detected in candidate resource selection and resource pool (re) selection may be excluded. The terminal device 110 may perform resource pool (re) selection, when SL C-LBT failure was detected for all RB-sets within a selected resource pool; or up to implementation of the terminal device 110 although the above condition is not met. The MAC layer may inform L1 layer of the RB set information where SL C-LBT failure was detected, and the L1 layer may perform the resource exclusion for the RB set that SL C-LBT failure was detected. It may be up to an implementation of the terminal device 110 to select a resource pool out of resource pools that has at least one RB-set that SL C-LBT failure was not detected.

Regarding SL C-LBT failure recovery in mode 1, it may depend on the implementation of the network device 120 after the terminal device 110 reporting SL C-LBT failure indication.

Regarding SL C-LBT failure recovery in mode 2 for RRC connected terminal device, SL C-LBT failure indication may be reported to the network device 120 also for mode 2, RRC connected terminal device.

Regarding SL C-LBT failure and sidelink synchronization signal block (S-SSB) , LBT failure indication may be counted regardless of whether LBT failure was provided because of S-SSB transmission or data transmission when RB set for S-SSB transmission belongs to the selected TX resource pool. Regarding SL C-LBT failure and physical sidelink feedback channel (PSFCH) , LBT failure indication may be counted regardless of whether LBT failure was provided because of PSFCH transmission or not when RB set for PSFCH transmission belongs to the selected TX resource pool.

Regarding SL C-LBT cancellation, for mode 1, SL C-LBT may be cancelled upon SL C-LBT failure MAC CE transmission. Regarding SL enhanced LCP, for shared COT, CAPC restriction may be applicable to enhanced LCP.

Regarding multiple consecutive sidelink transmission (MCSt) , it may be feasible to select the resource for a single transport block (TB) in MAC layer and concatenate across separate resource selection triggers across TBs in a best-effort manner. It may be feasible to provide a new parameter “number of slots for MCSt” to L1 when triggering resource (re-) selection for MCSt.

Regarding best-matched rule for a non-standardized physical downlink shared channel (PDSCH) resource element (RE) mapping and quasi co-location indicator (PQI) , priority may not be considered in best-matched rule. Regarding multiple PSFCH occasions, in case of multiple PSFCH occasion per PSCCH/PSSCH, if HARQ ACK/NACK is successfully transmitted in one PSFCH occasion, the RX terminal device may start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the first slot after the end of the corresponding PSFCH transmission carrying the SL HARQ feedback. In case of multiple PSFCH occasion per PSCCH/PSSCH, if the LBT failure happens in all PSFCH occasions, RX terminal device may start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the first slot after the end of the last PSFCH occasion for the SL HARQ feedback.

Regarding SL discontinuous reception (DRX) active time, shared COT may not be defined as SL DRX active time. If an additional ID is introduced, the additional ID may be revisited. Regarding SL CAPC when CAPC of the default SLRB is not configured, the terminal device 110 may select the lowest CAPC priority level (or highest CAPC value) among the associated quality of service (QoS) flows.

Some example solutions on the SL LBT failure are described above. However, some issues remain pending. For example, SL-U is introduced to enhance sidelink communication. In this situation, if a terminal device operating in mode 2 is in an RRC_IDLE or RRC_INACTIVE state, how to cancel a LBT failure for the terminal device needs to be specified.

To this end, some embodiments of the present disclosure provide a solution for LBT failure cancellation in SL communication. Reference is made to FIG. 2, which illustrates a signaling flow 200 of LBT failure cancellation in accordance with some embodiments of the present disclosure. For the purposes of discussion, the signaling flow 200 will be discussed with reference to FIG. 1, for example, by using the terminal device 110 and the network device 120. In some embodiments, the terminal device 110 may operate in mode 2 for SL communication and is in an idle or inactive state with the network device 120, for example, in the RRC_IDLE state or RRC_INACTIVE state.

As shown in FIG. 2, in some embodiments, the network device 120 may transmit (210) a configuration for LBT failure cancellation to the terminal device 110, which is also referred to as a cancellation configuration. The cancellation configuration may include or indicate at least one of an LBT failure ratio threshold, one or more timers for LBT cancellation, as will be described below in detail. Accordingly, the terminal device 110 may receive (220) the cancellation configuration from the network device 120 and then perform the LBT failure cancellation.

The terminal device 110 may determine (230) LBT failure information about at least one consistent LBT failure occurring on at least one RB set of the terminal device 110. Then, based on the LBT failure information, the terminal device 110 may perform an LBT failure cancellation.

Depending on the granularity of the LBT failure cancellation, different RB sets may be considered. In some embodiments, the at least one RB set may be within configured resources of the terminal device 110, and the LBT information may include an LBT failure ratio of the configured resources. In such embodiments, the terminal device 110 may determine the LBT failure ratio based on the number of RB sets for which consistent LBT failures are detected and a total number of RB sets of the configured resources. If the determined LBT failure ratio exceeds a configured LBT failure ratio threshold, the terminal device 110 may cancel all the consistent LBT failures in the configured resources.

In an example, the LBT failure cancellation may be performed per terminal device granularity. The terminal device 110 may be configured with an LBT failure ratio threshold. The terminal device 110 may compute the LBT failure ratio as a ratio of the number of RB sets which are detected as consistent LBT failure to the total number of RB sets in the configured resources. If the computed LBT failure ratio exceeds the LBT failure ratio configured by the network device 120, the terminal device 110 may cancel all the triggered consistent LBT failure in the configured resources.

In some embodiments, the configured resources may include a resource pool selected from a plurality of configured resource pools of the terminal device 110. In such embodiments, the LBT failure ratio may be computed as the ratio of the number of RB sets which are detected as consistent LBT failure to the total number of RB sets in the configured resource pool. If the computed LBT failure ratio is above the configured LBT failure ratio, the terminal device 110 may cancel all the triggered consistent LBT failure in selected resource pool.

Alternatively, or in addition, in some embodiments, the configured resources may include a configured bandwidth part (BWP) of the terminal device 110. In such embodiments, the LBT failure ratio may be computed as the ratio of the number of RB sets which are detected as consistent LBT failure to the total number of RB sets in the configured BWP. If the computed LBT failure ratio is above the configured LBT failure ratio, the terminal device 110 may cancel all the triggered consistent LBT failure in the configured BWP.

Alternatively, or in addition, in some embodiments, the configured resources may include a configured carrier of the terminal device 110. In such embodiments, the LBT failure ratio may be computed as the ratio of the number of RB sets which are detected as consistent LBT failure to the total number of RB sets in the configured carrier. If the computed LBT failure ratio is above the configured LBT failure ratio, the terminal device 110 may cancel all the triggered consistent LBT failure in the configured carrier.

As an example without any limitation, Table 1 shows an example of how to perform the LBT failure cancellation per UE granularity.

Table 1

In Table 1, “lbtFailureThres” represent the LBT failure ratio threshold.

In some embodiments, the at least one RB set may be in a target resource pool that is previously selected from a plurality of configured resource pools of the terminal device 110. In other words, the LBT failure cancellation may be performed per resource pool granularity. In such embodiments, if a certain condition is met, the terminal device 110 may cancel all the triggered consistent LBT failures for each RB set within the previously selected resource pool.

In some embodiments, if a resource pool reselection procedure is triggered, the terminal device 110 may cancel the at least one consistent LBT failure in the target resource pool. For example, upon the terminal device 110 triggers resource pool reselection when a consistent LBT failure is detected, the terminal device 110 may cancel all the triggered consistent LBT failures for each RB set within the previously selected resource pool.

In some embodiments, if a resource pool reselection procedure is triggered and a first timer is triggered, the terminal device 110 may cancel the at least one consistent LBT failure in the target resource pool upon expiration of the first timer. For example, the network device 120 may configure the terminal device 110 with the first timer for LBT failure cancellation. Upon the terminal device 110 triggers resource pool reselection when the consistent LBT failure is detected, the configured first timer may be triggered. Then, upon the expiration of the first timer, the terminal device 110 may cancel all the triggered consistent LBT failure for each RB set within the previously selected resource pool.

In some embodiments, upon trigger of a resource pool reselection procedure, the terminal device 110 may trigger a second timer. The second timer may be the same as or different from the first timer. If a COT sharing is obtained for an RB set in the target resource pool, the terminal device 110 may stop the second timer and cancel the at least one consistent LBT failure in the target resource pool. For example, the network device 120 may configure the terminal device 110 with the second timer for LBT failure cancellation. Upon the terminal device 110 triggers resource pool reselection when the consistent LBT failure is detected, the configured second timer may be triggered. When the terminal device 110 gets COT sharing for the RB set within the previously selected resource pool, the terminal device 110 may stop the second timer and cancel all the triggered consistent LBT failures for each RB set within the previously selected resource pool.

Some example embodiments regarding the use of a timer are described. Other embodiments are possible. In some embodiments, resource pool reselection may not be a condition for triggering a timer. For example, upon detection of a consistent LBT failure, the terminal device 110 may trigger a certain timer for LBT failure cancellation. Upon expiration of the timer or upon obtaining the COT sharing for an RB set within the previously selected resource pool, the terminal device 110 may cancel all the triggered consistent LBT failures for each RB set within the previously selected resource pool.

As an example without any limitation, Table 2 shows an example of how to perform the LBT failure cancellation per resource pool granularity.

Table 2

In Table 2, “timer-A” represent a timer for LBT failure cancellation.

In some embodiments, the LBT failure cancellation may be performed per RB set granularity. If a condition is met, the terminal device 110 may cancel the consistent LBT failure for a specific RB set.

In some embodiments, if a consistent LBT failure is detected for an RB set, the terminal device 110 may trigger a third timer for this RB set. Upon expiration of the third timer, the terminal device 110 may cancel the consistent LBT failure for this RB set. For example, the terminal device 110 may be configured with a timer for each RB set. Upon the terminal device 110 detects the consistent LBT failure for one RB set which an index j (denoted as RB setj) , the corresponding timer for the RB setj may be triggered. Upon the expiration of the timer for the RB setj, the terminal device 110 may cancel all the triggered consistent LBT failure for this RB setj.

In some embodiments, if a COT sharing is obtained for an RB set for which the consistent LBT failure is detected, the terminal device 110 may cancel the consi stent LBT failure for this RB set. For example, the terminal device 110 may detect a consistent LBT failure for one RB set with an index m (denoted as RB setm) . If the terminal device 110 gets COT sharing for this RB setm from another terminal device, the terminal device 110 may cancel the consistent LBT failure for this RB setm.

As an example without any limitation, Table 3 shows an example of how to perform the LBT failure cancellation per RB set granularity.

Table 3

In Table 3, “timer-B” represent a timer for LBT failure cancellation.

Example embodiments regarding the LBT failure cancellation are described above. The terminal device can maintain the LBT failure state per a suitable granularity. In this way, consistent LBT failure can be cancelled duly and efficiency of the sidelink communication can be improved.

Another issue remains to be solved for the LBT in sidelink communication. When an LBT failure is encountered for the transmission of S-SSB and/or PSFCH of which the resource is not overlapped in the frequency domain with resource pool configuration, then how to handle such an LBT failure needs to be specified. Some embodiments of the present disclosure propose a solution for reporting LBT failure.

Reference is made to FIG. 3, which illustrates a signaling flow 300 of LBT failure reporting in accordance with some embodiments of the present disclosure. For the purposes of discussion, the signaling flow 300 will be discussed with reference to FIG. 1, for example, by using the terminal device 110 and the network device 120.

As shown in FIG. 3, the terminal device 110 may detect (310) an LBT failure for an RB set associated with a sidelink communication. The RB set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions. Specifically, the RB set is not overlapped with the first resource pool in the frequency domain.

In some embodiments, the first resource pool may be a resource pool selected from a plurality of resource pools configured by the network device 120. For example, if the terminal device 110 is operating in mode 2, the first resource pool may be the selected resource pool. In some embodiments, the first resource pool may be a resource pool configured by the network device 120 for using by the terminal device 110, which is also referred to as a using resource pool. For example, if the terminal device 110 is operating in mode 1, the first resource pool may be the dedicated resource pool for the terminal device 110.

In some embodiments, the RB set for which the LBT failure is detected may be used for a transmission other than the PSSCH transmission and the PSCCH transmission. For example, the RB set may be used for S-SSB transmission or for PSFCH transmission. Reference now is made is FIG. 4A. As shown, the resource 410 is not overlapped with the first resource pool for PSSCH transmission and PSCCH transmission in the frequency domain.

Reference is made back to FIG. 3. The MAC entity of the terminal device 110 may detect or determine the LBT failure for the RB set in any suitable manner. In some embodiments, the LBT failure for the RB set may be indicated by the physical layer to the MAC entity. In an example, the physical layer may indicate the LBT failure to the MAC entity via a dedicated or exceptional LBT failure indication. Such an indication may indicate that the LBT failure occurs due to SSB transmission or PSFCH transmission. For example, if the MAC entity is indicated by the physical layer with the exceptional LBT failure indication, the MAC entity may determine that the LBT failure occurs due to the S-SSB transmission or PSFCH transmission.

Alternatively, or in addition, in another example, the physical layer may indicate the MAC entity via a cause value for the LBT failure, which is also referred to an LBT failure cause value. The cause value may indicate one of the PSSCH transmission, the PSCCH transmission, the SSB transmission or the PSFCH transmission. By using the cause value, the MAC entity of the terminal device 110 may know whether the RB set is overlapped in frequency domain the selected resource pool or the using resource pool.

In some embodiments, the MAC entity of the terminal device 110 may detect or determine the LBT failure for the RB set. For example, the MAC entity may be aware of the usage of different RB sets. The physical layer may indicate the MAC entity that the LBT failure is detected for a certain RB set. The MAC entity may determine that the RB set is used for SSB transmission or PSFCH transmission. Accordingly, the MAC entity may determine that the RB set for which the LBT failure is detected is not frequency shared with the selected resource pool or the using resource pool.

Continuing with the process 300, if the LBT failure is detected, the terminal device 110 may transmit (320) information associated with the LBT failure to the network device 120 based on a connection state of the terminal device 110 with the network de vice 120. For example, the terminal device 110 may transmit an LBT failure report to the network device 120.

In some embodiments, if the terminal device 110 is in a connected state with the network device 120, the terminal device 110 may transmit a report of the LBT failure for the RB set to the network device 120. For example, if the LBT failure is detected on the RB set for the S-SSB transmission or the PSFCH transmission (either based on indications from the physical layer or by the MAC entity) , the terminal device 110 may report such an LBT failure to the network device 120 if the terminal device 110 is in RRC_CONNECTED state.

In some embodiments, the terminal device 110 may determine whether a consistent LBT failure occurs for the RB set by counting indications of the LBT failure from the physical layer. If the terminal device 110 (for example, the MAC entity of the terminal device 110) determines that the consistent LBT failure occurs for the RB set, the terminal device 110 may transmit a report of the consistent LBT failure to the network device 120 if the terminal device 110 is in a connected state with the network device 120. For example, if the consistent LBT failure occurs when the MAC entity counting the LBT failure indications for the related RB set, the terminal device 110 may report such consistent LBT failure to the network device 120 if the terminal device 110 is in RRC_CONNECTED state.

In some embodiments, if the terminal device 110 is in an idle state or an inactive state, the terminal device 110 may trigger a procedure for entering into a connected state with the network device 120. If the terminal device 110 is in the connected state, the terminal device 110 may transmit the information associated with the LBT failure to the network device 120. For example, if the LBT failure is detected on the RB set for the S-SSB transmission or the PSFCH transmission (either based on indications from the physical layer or by the MAC entity) , and if the terminal device 110 is in the RRC_IDLE state or the RRC_INACTIVE state but stay in coverage of the network device 120, the terminal device 110 may be triggered to access into RRC_CONNECTED state. If the terminal device 110 has accessed into RRC_CONNECTED state, the terminal device 110 may report such LBT failure (the LBT failure on the RB set or the consistent LBT failure on the RB set) to the network device 120. In some embodiments, the terminal device 110 may additionally report the count of the LBT failure indications to the network device 120.

In some embodiments, the RB set for which the LBT failure is detected may be overlapped in frequency domain with a second resource pool configured by the network device 120 but different from the first resource pool. For example, the RB set may be frequency shared with the second resource pool. In some embodiments, the first resource pool may be one of the plurality of resource pools configured by the network device 120, for example, the selected resource pool, and the second resource pool may be another one of the plurality of configured resource pools. Reference is now made to FIG. 4B. As shown, the resource 410 is overlapped with the resource within the second resource pool in the frequency domain.

In such embodiments, the terminal device 110 (for example, the MAC entity) may count indications of the LBT failure from the physical layer. For example, if the MAC entity of the terminal device 110 detects the RB set for which the LBT failure happened is frequency shared with other configured resource pool other than the selected resource pool or the using resource pool, the MAC entity may count LBT failure indications of the related RB set.

In some embodiments, the terminal device 110 may determine whether a consistent LBT failure occurs for the RB set based on counting the indications. If the consistent LBT failure occurs for the RB set, the terminal device 110 may transmit, to the network device 120, a report of the consistent LBT failure within the second resource pool if the terminal device 110 is in a connected state with the network device 120. Alternatively, or in addition, the terminal device 110 may exclude the second resource pool from future resource pool selection or reselection. Alternatively, or in addition, the terminal device 110 may perform a resource pool selection or reselection based on a number of RB sets for which LBT failure is detected in each resource pool of the plurality of configured resource pools. For example, the plurality of configured resource pools may be ordered from lowest to highest according to the number of RB sets for which LBT failure is detected in the respective resource pools. The terminal device 110 may perform the resource pool selection or reselection from the plurality of configured resource pools based on the order.

In an example, if the consistent LBT failure is happened for the RB set within other configured resource pool other than the selected resource pool or using resource pool, the terminal device 110 may report the consistent LBT failure within the related resource pool towards the network device 120, if the terminal device 110 is in RRC_CONNECTED state. Alternatively, or in addition, the terminal device 110 may exclude this configured resource pool for the future resource pool reselection, for example, if the terminal device 110 is in RRC_IDLE/INACTIVE state and if all the included RB sets are detected as consistent LBT failure and if the consistent LBT failure related to the configured resource pool is not cancelled. Alternatively, or in addition, the terminal device 110 may select or reselect the resource pools across the order from lowest number of RB sets with LBT failure detected to highest number of RB sets with LBT failure detected.

Example embodiments regarding the LBT failure reporting are described above. The terminal device can report the exceptional LBT failure to the network device to resume or maintain the SSB transmission or PSFCH transmission. In this way, efficiency of the sidelink communication can be improved.

Another issue remains to be solved for the sidelink communication. For SL CA, PDCP duplication can be activated for packet transmissions. However, if the transmission in one leg fails to be performed in a transmission opportunity due to any possible reasons, how to align the original packet transmission and the duplicated packet transmission needs to be specified. Some embodiments of the present disclosure propose a solution for reporting LBT failure.

Reference is made to FIG. 5, which illustrates a signaling flow 500 of packet transmission suspending in accordance with some embodiments of the present disclosure. For the purposes of discussion, the signaling flow 500 will be discussed with reference to FIG. 1, for example, by using the terminal device 110-1, the terminal device 120-2 and the network device 120. In the example, the terminal device 110-1 may be the TX device and the terminal device 110-2 may be RX device.

As shown in FIG. 5, the terminal device 110-1 may perform (510) packet transmission with the terminal device 110-2 based on PDCP duplication. In other words, for a packet, an original packet transmission and a duplicated packet transmission may be performed. As such, the terminal device 110-2 may receive both the original packet and the duplicated packet from the terminal device 110-1.

The terminal device 110-1 may determine (540) that at least one transmission of the original packet transmission and the duplicated packet transmission is suspended, for example interrupted due to some reason. The suspending of the at least one transmission may occur for any suitable time duration or for any suitable number of transmission occasions or opportunities.

The cause of the suspending of the at least one transmission may include a re-evaluation of a resource reserved for the at least one transmission, which is also referred to as resource re-evaluation. Alternatively, or in addition, the cause may include a preemption of the resource reserved for the at least one transmission, which is also referred to as resource re-preemption. Alternatively, or in addition, the cause may include a configuration of the at least one transmission by a network device 120, which is also referred to as network configuration. For example, as shown in FIG. 5, the network device 120 may transmit (520) a suspending indication to the terminal device 110. The suspending indication may indicate the terminal device 110 to suspend or interrupt the at least one transmission. As examples without any limitation, the suspending indication may be a configuration to deactivate the PDCP duplication temporally or a carrier unavailable indication.

If the at least one transmission is suspended, the terminal device 110-1 may transmit (550) , to the terminal device 110-2, information indicating the at least one suspended transmission, which is also referred to as “suspended transmission information” for purpose of discussion.

The suspended transmission information may include any suitable indication or information to indicate the RX terminal device of the at least one suspended transmission. In some embodiments, the suspended transmission information may include an indication of a temporary de-activation for the at least one suspended transmission. For example, a temporary PDCP duplication de-activation indication may be transmitted to the terminal device 110-2. In some embodiments, the indication may indicate the cause of the suspending of the at least one transmission, for example, resource re-evaluation, resource-preemption, or network configuration.

Alternatively, or in addition, the suspended transmission information may include a counter indicating a number of transmission occasions for recovering the at least one suspended transmission. For example, a de-activation transmission counter may be indicated to the terminal device 110-2. The de-activation transmission counter may indicate after how many transmission opportunities or occasions, PDCP duplication will be recovered.

Alternatively, or in addition, the suspended transmission information may include a timer indicating a time duration for recovering the at least one suspended transmission. For example, a de-activation transmission timer may be indicated to the terminal device 110-2. The de-activation transmission timer may indicate after how long the PDCP duplication will be recovered.

Alternatively, or in addition, the suspended transmission information may include carrier information for recovering the at least one suspended transmission. For example, a leg indicator may be transmitted to the terminal device 110-2. The leg indicator may indicate that the temporary PDCP duplication de-activation is to happen in the carrier for the original packet transmission or in the carrier for the duplicated packet transmission, or in both the carriers for original packet transmission and duplicated packet transmission.

Alternatively, or in addition, in some embodiments, the suspended transmission information may include an indication about how to perform HARQ feedback to the at least one suspended transmission. For example, the suspended transmission information may include an indication for disabling the HARQ feedback of the at least one suspended transmission, which is also referred to as HARQ feedback disabled indication.

Alternatively, or in addition, the suspended transmission information may include an indication of a HARQ feedback scheme to be used for the at least one suspended transmission, which is also referred to as HARQ feedback option indication. For example, the HARQ feedback option indication may indicate which one of the ACK/NACK feedback option or NACK only feedback option is to be used for the at least one suspended transmission.

The suspended transmission information may be transmitted in any suitable signaling. For example, the suspended transmission information may be carried within a sidelink MAC CE. Alternatively, or in addition, the suspended transmission information may be carried in a RRC signaling, such as PC5-RRC signaling. Alternatively, or in addition, the suspended transmission information may be carried in a header of an original packet or a duplicated packet transmitted to the terminal device 110-2, such as a MAC PDU header. Specifically, if one transmission of the original packet transmission and the duplicated packet transmission is suspended, the suspended transmission information may be carried in the header of the other packet of which the transmission is not suspended. Alternatively, or in addition, the suspended transmission information may be carried in the sidelink control information (SCI) .

In some embodiments, if the suspended transmission information is carried in the header of the transmitted packet or SCI, the suspended transmission information may be only carried within the packet transmitted in the carrier of which PDCP duplication de-activation does not happen.

The terminal device 110-2 may receive the suspended transmission information from the terminal device 110-1. Accordingly, the terminal device 110-2 may disable the HARQ feedback for the at least one suspended transmission. Alternatively, the terminal device 110-2 may determine a HARQ feedback scheme to be used for the at least one suspended transmission.

In an example, if a RX UE receives the suspended transmission information (for example, the PDCP duplication deactivation related information) from the TX UE, correspondingly, and if previously, the transmission of the HARQ process on the corresponding carrier of which PDCP duplication is activated, is configured with enabled HARQ feedback, the MAC entity of the Rx UE may configure the HARQ process with disabled HARQ feedback for the suspended transmission. Alternatively, the MAC entity of the Rx UE may configure the HARQ process with NACK only HARQ feedback option or the ACK/NACK feedback option for the suspended transmission.

In another example, if the RX UE receives the suspended transmission information (for example, the PDCP duplication deactivation related information) from the TX UE, correspondingly, and if previously, the transmission of the HARQ process on the corresponding carrier of which PDCP duplication is de-activated, is configured with one option of the NACK only HARQ feedback option or the ACK/NACK feedback option, the MAC entity of the Rx UE may configure the HARQ process with disabled HARQ feedback for the suspended transmission. Alternatively, the MAC entity of the Rx UE may configure the HARQ process with the other option of the NACK only HARQ feedback option or the ACK/NACK feedback option for the suspended transmission.

Example embodiments regarding the suspending of transmission based on PDCP duplication are described above. In this way, information about the suspended transmission can be align from the TX terminal device to the RX terminal device. As such, the RX terminal device can correctly perform the HARQ feedback. In this way, reliability of the sidelink communication between the terminal devices can be improve d.

FIG. 6 illustrates a flowchart of a communication method 600 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 110 in FIG. 1.

At block 610, the terminal device determines LBT failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device.

At block 620, the terminal device performs a LBT failure cancellation at least based on the LBT failure information.

In some example embodiments, the at least one resource block set is within configured resources of the terminal device, the LBT failure information comprises an LBT failure ratio of the configured resources, and the terminal device may determine the LBT failure ratio based on the number of resource block sets for which consistent LBT failures are detected and a total number of resource block sets of the configured resources; and in accordance with a determination that the LBT failure ratio is above a configured LBT failure ratio threshold, cancel all the consistent LBT failures in the configured resources.

In some example embodiments, the configured resources comprise at least one of: a resource pool selected from a plurality of configured resource pools of the terminal device, a configured bandwidth part of the terminal device, or a configured carrier of the terminal device.

In some example embodiments, the at least one resource block set is in a target resource pool that is previously selected from a plurality of configured resource pools of the terminal device, and the terminal device may in accordance with a determination that a resource pool reselection procedure is triggered, cancel the at least one consistent LBT failure in the target resource pool, or in accordance with a determination that a resource pool reselection procedure is triggered and a first timer is triggered, cancel the at least one consistent LBT failure in the target resource pool upon expiration of the first timer.

In some example embodiments, the at least one resource block set is in a target resource pool that is previously selected from a plurality of configured resource pools of the terminal device, and the terminal device may trigger a second timer upon trigger of a resource pool reselection procedure; and in accordance with a determination that a channel occupancy time (COT) sharing is obtained for a resource block set in the target resource pool, stop the second timer, and cancel the at least one consistent LBT failure in the target resource pool.

In some example embodiments, the terminal device may in response to a detection of a consistent LBT failure for a first resource block set of the at least one resource block set, trigger a third timer for the first resource block set; and in response to expiration of the third timer, cancel the consistent LBT failure for the first resource block set.

In some example embodiments, the terminal device may in accordance with a determination that a COT sharing is obtained for a second resource block set of the at least one resource block set, cancel a corresponding consistent LBT failure for the second resource block set.

FIG. 7A illustrates a flowchart of a communication method 700 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the terminal device 110 in FIG. 1.

At block 710, the terminal device detects a LBT failure for a resource block set associated with a sidelink communication. The resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions.

At block 720, in accordance with a determination that the LBT failure is detected, the terminal device transmits information associated with the LBT failure to a network device based on a connection state of the terminal device with the network device.

In some example embodiments, the terminal device may indicate the LBT failure by a physical layer of the terminal device to a medium access control (MAC) entity of the terminal device via at least one of the following: an exceptional LBT failure indication indicating that the LBT failure occurs due to Synchronization Signal Block (SSB) transmission or Physical Sidelink Feedback Channel (PSFCH) transmission, or a cause value of the LBT failure comprising at least one of: Physical Sidelink Control Channel (PSCCH) /Physical Sidelink Shared Channel (PSSCH) transmission, SSB transmission, or PSFCH transmission.

In some example embodiments, the terminal device may indicate, by a physical layer of the terminal device to a MAC entity of the terminal device, a detection of the LBT failure on the resource block set; and determine, by the MAC entity, that the resource block set for which the LBT failure is detected is not overlapped with the first resource pool.

In some example embodiments, the terminal device may in accordance with a determination that the terminal device is in a connected state, transmit a report of the LBT failure for the resource block set to the network device.

In some example embodiments, the terminal device may determine whether a consistent LBT failure occurs for the resource block set by counting indications of the LBT failure; and in accordance with a determination that the consistent LBT failure occurs for the resource block set, transmit a report of the consistent LBT failure to the network device if the terminal device is in a connected state.

In some example embodiments, the terminal device may in accordance with a determination that the terminal device is in an idle state or an inactive state, trigger a procedure for entering into a connected state with the terminal device; and in accordance with a determination that the terminal device is in the connected state, transmit the information associated with the LBT failure to the network device.

In some example embodiments, the resource block set is overlapped in frequency domain with a second resource pool configured by the network device and different from the first resource pool, and the terminal device may count, by a MAC entity of the terminal device, indications of the LBT failure from a physical layer of the terminal device.

In some example embodiments, the first resource pool is one of a plurality of resource pools configured by the network device, and the second resource pool is another one of the plurality of resource pools different from the first resource pool.

In some example embodiments, the terminal device may determine whether a consistent LBT failure occurs for the resource block set based on counting the indications; and in accordance with a determination that the consistent LBT failure occurs for the resource block set, perform at least one of: transmitting, to the network device, a report of the consistent LBT failure within the second resource pool if the terminal device is in a connected state with the network device, excluding the second resource pool from future resource pool selection or reselection, or performing a resource pool selection or reselection based on a number of resource block sets for which LBT failure is detected in each resource pool of a plurality of resource pools configured by the network device.

In some example embodiments, the first resource pool comprises one of the following: a resource pool selected from a plurality of resource pools configured by the network device, or a resource pool configured by the network device for using by the terminal device.

FIG. 7B illustrates a flowchart of a communication method 750 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 750 will be described from the perspective of the network device 120 in FIG. 1.

At block 760, the network device receives, from a terminal device, information associated with a Listen Before Talk (LBT) failure based on a connection state of the terminal device with the network device. The LBT failure is detected for a resource block set associated with a sidelink communication, and the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions.

In some example embodiments, the terminal device is in a connected state, and the network device may receive a report of the LBT failure for the resource block set from the terminal device.

In some example embodiments, the terminal device is in a connected state, and the network device may receive, from the terminal device, a report of a consistent LBT failure occurring for the resource block set, wherein the consistent LBT failure is determined by counting indications of the LBT failure for the resource block set.

In some example embodiments, the network device may perform a procedure for causing the terminal device to enter into a connected state with the network device; and in accordance with a determination that the terminal device is in the connected state, receive the information associated with the LBT failure from the terminal device.

In some example embodiments, the resource block set is overlapped in frequency domain with a second resource pool configured by the network device and different from the first resource pool, and the network device may receive, from the terminal device, a report of a consistent LBT failure within the second resource pool if the terminal device is in a connected state with the network device, wherein the consistent LBT failure is determined by counting indications of the LBT failure for the resource block set.

In some example embodiments, the first resource pool comprises one of the following: a resource pool selected by the terminal device from a plurality of resource pools configured by the network device, or a resource pool configured by the network device for using by the terminal device.

FIG. 8 illustrates a flowchart of a communication method 800 implemented at a first terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the terminal device 110-1 in FIG. 1.

At block 810, the first terminal device performs packet transmissions with a second terminal device based on PDCP duplication.

At block 820, in accordance with a determination that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended, the first terminal device transmits, to the second terminal device, information indicating the at least one suspended transmission.

In some example embodiments, the information comprises at least one of: an indication of a temporary de-activation for the at least one suspended transmission, a counter indicating a number of transmission occasions for recovering the at least one suspended transmission, a fourth timer indicating a time duration for recovering the at least one suspended transmission, carrier information for recovering the at least one suspended transmission, an indication for disabling a Hybrid Automatic Repeat reQuest (HARQ) feedback of the at least one suspended transmission, or an indication of a HARQ feedback scheme to be used for the at least one suspended transmission.

In some example embodiments, the information further indicates a cause of the suspending of the at least one transmission, and the cause comprises at least one of: a re-evaluation of a resource reserved for the at least one transmission, a preemption of the resource reserved for the at least one transmission, or a configuration of the at least one transmission by a network device.

In some example embodiments, the information is transmitted via at least one of: a sidelink medium access control control element (MAC CE) , a radio resource control (RRC) signalling, a header of an original packet or a duplicated packet transmitted to the second terminal device, or sidelink control information (SCI) .

FIG. 9 illustrates a flowchart of a communication method 900 implemented at a second terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the terminal device 110-2 in FIG. 1.

At block 910, the second terminal device performs packet transmissions with a first terminal device based on PDCP duplication.

At block 920, the second terminal device receives, from the first terminal device, information indicating that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended.

In some example embodiments, the second terminal device may perform at least one of: disabling a Hybrid Automatic Repeat reQuest (HARQ) feedback for the at least one suspended transmission, or determining a HARQ feedback scheme to be used for the at least one suspended transmission.

FIG. 10 is a simplified block diagram of a device 1000 that is suitable for implementing embodiments of the present disclosure. The device 1000 can be considered as a further example implementation of any of the devices as shown in FIG. 1. Accordingly, the device 1000 can be implemented at or as at least a part of the terminal device 110 or the network device 120.

As shown, the device 1000 includes a processor 1010, a memory 1020 coupled to the processor 1010, a suitable transceiver 1040 coupled to the processor 1010, and a communication interface coupled to the transceiver 1040. The memory 1020 stores at least a part of a program 1030. The transceiver 1040 may be for bidirectional communications or a unidirectional communication based on requirements. The transceiver 1040 may include at least one of a transmitter 1042 and a receiver 1044. The transmitter 1042 and the receiver 1044 may be functional modules or physical entities. The transceiver 1040 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.

The program 1030 is assumed to include program instructions that, when executed by the associated processor 1010, enable the device 1000 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGS. 1 to 9. The embodiments herein may be implemented by computer software executable by the processor 1010 of the device 1000, or by hardware, or by a combination of software and hardware. The processor 1010 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 1010 and memory 1020 may form processing means 1050 adapted to implement various embodiments of the present disclosure.

The memory 1020 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 1020 is shown in the device 1000, there may be several physically distinct memory modules in the device 1000. The processor 1010 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1000 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

According to embodiments of the present disclosure, a terminal device comprising a circuitry is provided. The circuitry is configured to: determine Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and perform a LBT failure cancellation at least based on the LBT failure information. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the terminal device as discussed above.

According to embodiments of the present disclosure, a terminal device comprising a circuitry is provided. The circuitry is configured to: detect a Listen Before Talk (LBT) failure for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions; and in accordance with a determination that the LBT failure is detected, transmit information associated with the LBT failure to a network device based on a connection state of the terminal device with the network device. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the terminal device as discussed above.

According to embodiments of the present disclosure, a network device comprising a circuitry is provided. The circuitry is configured to: receive, from a terminal device, information associated with a Listen Before Talk (LBT) failure based on a connection state of the terminal device with the network device, and wherein the LBT failure is detected for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the network device as discussed above.

According to embodiments of the present disclosure, a first terminal device comprising a circuitry is provided. The circuitry is configured to: perform packet transmissions with a second terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and in accordance with a determination that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended, transmit, to the second terminal device, information indicating the at least one suspended transmission. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the first terminal device as discussed above.

According to embodiments of the present disclosure, a second terminal device comprising a circuitry is provided. The circuitry is configured to: perform packet transmissions with a first terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and receive, from the first terminal device, information indicating that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the second terminal device as discussed above.

The term “circuitry” used herein may refer to hardware circuits and/or combinations of hardware circuits and software. For example, the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware. As a further example, the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions. In a still further example, the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation. As used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.

According to embodiments of the present disclosure, a first apparatus is provided. The first apparatus comprises means for determining Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and means for performing a LBT failure cancellation at least based on the LBT failure information. In some embodiments, the first apparatus may comprise means for performing the respective operations of the method 600. In some example embodiments, the first apparatus may further comprise means for performing other operations in some example embodiments of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

According to embodiments of the present disclosure, a second apparatus is provided. The second apparatus comprises means for detecting a Listen Before Talk (LBT) failure for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions; and means for in accordance with a determination that the LBT failure is detected, transmitting information associated with the LBT failure to a network device based on a connection state of the terminal device with the network device. In some embodiments, the second apparatus may comprise means for performing the respective operations of the method 700. In some example embodiments, the second apparatus may further comprise means for performing other operations in some example embodiments of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

According to embodiments of the present disclosure, a fifth apparatus is provided. The fifth apparatus comprises means for receiving, from a terminal device, information associated with a Listen Before Talk (LBT) failure based on a connection state of the terminal device with the network device, and means for wherein the LBT failure is detected for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions. In some embodiments, the fifth apparatus may comprise means for performing the respective operations of the method 750. In some example embodiments, the third apparatus may further comprise means for performing other operations in some example embodiments of the method 750. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

According to embodiments of the present disclosure, a third apparatus is provided. The third apparatus comprises means for performing packet transmissions with a second terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and means for in accordance with a determination that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended, transmitting, to the second terminal device, information indicating the at least one suspended transmission. In some embodiments, the third apparatus may comprise means for performing the respective operations of the method 800. In some example embodiments, the third apparatus may further comprise means for performing other operations in some example embodiments of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

According to embodiments of the present disclosure, a fourth apparatus is provided. The fourth apparatus comprises means for performing packet transmissions with a first terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and means for receiving, from the first terminal device, information indicating that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended. In some embodiments, the fourth apparatus may comprise means for performing the respective operations of the method 900. In some example embodiments, the fourth apparatus may further comprise means for performing other operations in some example embodiments of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In summary, embodiments of the present disclosure provide the following aspects.

In an aspect, it is proposed a terminal device comprising: a processor configured to cause the terminal device to: determine Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and perform a LBT failure cancellation at least based on the LBT failure information.

In some embodiments, the at least one resource block set is within configured resources of the terminal device, the LBT failure information comprises an LBT failure ratio of the configured resources, and the terminal device is further caused to: determine the LBT failure ratio based on the number of resource block sets for which consistent LBT failures are detected and a total number of resource block sets of the configured resources; and in accordance with a determination that the LBT failure ratio is above a configured LBT failure ratio threshold, cancel all the consistent LBT failures in the configured re s ource s.

In some embodiments, the configured resources comprise at least one of: a resource pool selected from a plurality of configured resource pools of the terminal device, a configured bandwidth part of the terminal device, or a configured carrier of the terminal device.

In some embodiments, the at least one resource block set is in a target resource pool that is previously selected from a plurality of configured resource pools of the terminal device, and the terminal device is further caused to: in accordance with a determination that a resource pool reselection procedure is triggered, cancel the at least one consistent LBT failure in the target resource pool, or in accordance with a determination that a resource pool reselection procedure is triggered and a first timer is triggered, cancel the at least one consistent LBT failure in the target resource pool upon expiration of the first timer.

In some embodiments, the at least one resource block set is in a target resource pool that is previously selected from a plurality of configured resource pools of the terminal device, and the terminal device is further caused to: trigger a second timer upon trigger of a resource pool reselection procedure; and in accordance with a determination that a channel occupancy time (COT) sharing is obtained for a resource block set in the target resource pool, stop the second timer, and cancel the at least one consistent LBT failure in the target resource pool.

In some embodiments, the terminal device is further caused to: in response to a detection of a consistent LBT failure for a first resource block set of the at least one resource block set, trigger a third timer for the first resource block set; and in response to expiration of the third timer, cancel the consistent LBT failure for the first resource block set.

In some embodiments, the terminal device is further caused to: in accordance with a determination that a COT sharing is obtained for a second resource block set of the at least one resource block set, cancel a corresponding consistent LBT failure for the second resource block set.

In an aspect, it is proposed a terminal device comprising: a processor configured to cause the terminal device to: detect a Listen Before Talk (LBT) failure for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions; and in accordance with a determination that the LBT failure is detected, transmit information associated with the LBT failure to a network device based on a connection state of the terminal device with the network device.

In some embodiments, the terminal device is further caused to: indicate the LBT failure by a physical layer of the terminal device to a medium access control (MAC) entity of the terminal device via at least one of the following: an exceptional LBT failure indication indicating that the LBT failure occurs due to Synchronization Signal Block (SSB) transmission or Physical Sidelink Feedback Channel (PSFCH) transmission, or a cause value of the LBT failure comprising at least one of: Physical Sidelink Control Channel (PSCCH) /Physical Sidelink Shared Channel (PSSCH) transmission, SSB transmission, or PSFCH transmission.

In some embodiments, the terminal device is further caused to: indicate, by a physical layer of the terminal device to a MAC entity of the terminal device, a detection of the LBT failure on the resource block set; and determine, by the MAC entity, that the resource block set for which the LBT failure is detected is not overlapped with the first resource pool.

In some embodiments, the terminal device is further caused to: in accordance with a determination that the terminal device is in a connected state, transmit a report of the LBT failure for the resource block set to the network device.

In some embodiments, the terminal device is further caused to: determine whether a consistent LBT failure occurs for the resource block set by counting indications of the LBT failure; and in accordance with a determination that the consistent LBT failure occurs for the resource block set, transmit a report of the consistent LBT failure to the network device if the terminal device is in a connected state.

In some embodiments, the terminal device is further caused to: in accordance with a determination that the terminal device is in an idle state or an inactive state, trigger a procedure for entering into a connected state with the terminal device; and in accordance with a determination that the terminal device is in the connected state, transmit the information associated with the LBT failure to the network device.

In some embodiments, the resource block set is overlapped in frequency domain with a second resource pool configured by the network device and different from the first resource pool, and the terminal device is further caused to: count, by a MAC entity of the terminal device, indications of the LBT failure from a physical layer of the terminal device.

In some embodiments, the first resource pool is one of a plurality of resource pools configured by the network device, and the second resource pool is another one of the plurality of resource pools different from the first resource pool.

In some embodiments, the terminal device is further caused to: determine whether a consistent LBT failure occurs for the resource block set based on counting the indications; and in accordance with a determination that the consistent LBT failure occurs for the resource block set, perform at least one of: transmitting, to the network device, a report of the consistent LBT failure within the second resource pool if the terminal device is in a connected state with the network device, excluding the second resource pool from future resource pool selection or reselection, or performing a resource pool selection or reselection based on a number of resource block sets for which LBT failure is detected in each resource pool of a plurality of resource pools configured by the network device.

In some embodiments, the first resource pool comprises one of the following: a resource pool selected from a plurality of resource pools configured by the network device, or a resource pool configured by the network device for using by the terminal device.

In an aspect, it is proposed a network device comprising: a processor configured to cause the network device to: receive, from a terminal device, information associated with a Listen Before Talk (LBT) failure based on a connection state of the terminal device with the network device, and wherein the LBT failure is detected for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions.

In some embodiments, the terminal device is in a connected state, and the network device is further caused to: receive a report of the LBT failure for the resource block set from the terminal device.

In some embodiments, the terminal device is in a connected state, and the network device is further caused to: receive, from the terminal device, a report of a consistent LBT failure occurring for the resource block set, wherein the consistent LBT failure is determined by counting indications of the LBT failure for the resource block set.

In some embodiments, the network device is further caused to: perform a procedure for causing the terminal device to enter into a connected state with the network device; and in accordance with a determination that the terminal device is in the connected state, receive the information associated with the LBT failure from the terminal device.

In some embodiments, the resource block set is overlapped in frequency domain with a second resource pool configured by the network device and different from the first resource pool, and the network device is further caused to: receive, from the terminal device, a report of a consistent LBT failure within the second resource pool if the terminal device is in a connected state with the network device, wherein the consistent LBT failure is determined by counting indications of the LBT failure for the resource block set.

In some embodiments, the first resource pool comprises one of the following: a resource pool selected by the terminal device from a plurality of resource pools configured by the network device, or a resource pool configured by the network device for using by the terminal device.

In an aspect, it is proposed a first terminal device comprising: a processor configured to cause the first terminal device to: perform packet transmissions with a second terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and in accordance with a determination that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended, transmit, to the second terminal device, information indicating the at least one suspended transmission.

In some embodiments, the information comprises at least one of: an indication of a temporary de-activation for the at least one suspended transmission, a counter indicating a number of transmission occasions for recovering the at least one suspended transmission, a fourth timer indicating a time duration for recovering the at least one suspended transmission, carrier information for recovering the at least one suspended transmission, an indication for disabling a Hybrid Automatic Repeat reQuest (HARQ) feedback of the at least one suspended transmission, or an indication of a HARQ feedback scheme to be used for the at least one suspended transmission.

In some embodiments, the information further indicates a cause of the suspending of the at least one transmission, and the cause comprises at least one of: a re-evaluation of a resource reserved for the at least one transmission, a preemption of the resource reserved for the at least one transmission, or a configuration of the at least one transmission by a network device.

In some embodiments, the information is transmitted via at least one of: a sidelink medium access control control element (MAC CE) , a radio resource control (RRC) signalling, a header of an original packet or a duplicated packet transmitted to the second terminal device, or sidelink control information (SCI) .

In an aspect, it is proposed a second terminal device comprising: a processor configured to cause the second terminal device to: perform packet transmissions with a first terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and receive, from the first terminal device, information indicating that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended.

In some embodiments, the second terminal device is further caused to perform at least one of: disabling a Hybrid Automatic Repeat reQuest (HARQ) feedback for the at least one suspended transmission, or determining a HARQ feedback scheme to be used for the at least one suspended transmission.

In an aspect, a terminal device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the terminal device discussed above.

In an aspect, a first terminal device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the first terminal device discussed above.

In an aspect, a second terminal device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the second terminal device discussed above.

In an aspect, a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the terminal device discussed above.

In an aspect, a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first terminal device discussed above.

In an aspect, a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the second terminal device discussed above.

In an aspect, a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the terminal device discussed above.

In an aspect, a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first terminal device discussed above.

In an aspect, a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the second terminal device discussed above.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to FIGS. 1 to 10. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A terminal device comprising:

a processor configured to cause the terminal device to:

determine Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and

perform a LBT failure cancellation at least based on the LBT failure information.
The terminal device of claim 1, wherein the at least one resource block set is within configured resources of the terminal device, the LBT failure information comprises an LBT failure ratio of the configured resources, and the terminal device is further caused to:

determine the LBT failure ratio based on the number of resource block sets for which consistent LBT failures are detected and a total number of resource block sets of the configured resources; and

in accordance with a determination that the LBT failure ratio is above a configured LBT failure ratio threshold, cancel all the consistent LBT failures in the configured resources.
The terminal device of claim 1, wherein the at least one resource block set is in a target resource pool that is previously selected from a plurality of configured resource pools of the terminal device, and the terminal device is further caused to:

in accordance with a determination that a resource pool reselection procedure is triggered, cancel the at least one consistent LBT failure in the target resource pool, or

in accordance with a determination that a resource pool reselection procedure is triggered and a first timer is triggered, cancel the at least one consistent LBT failure in the target resource pool upon expiration of the first timer.
The terminal device of claim 1, wherein the at least one resource block set is in a target resource pool that is previously selected from a plurality of configured resource pools of the terminal device, and the terminal device is further caused to:

trigger a second timer upon trigger of a resource pool reselection procedure; and

in accordance with a determination that a channel occupancy time (COT) sharing is obtained for a resource block set in the target resource pool,

stop the second timer, and

cancel the at least one consistent LBT failure in the target resource pool.
A terminal device comprising:

a processor configured to cause the terminal device to:

detect a Listen Before Talk (LBT) failure for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions; and

in accordance with a determination that the LBT failure is detected, transmit information associated with the LBT failure to a network device based on a connection state of the terminal device with the network device.
The terminal device of claim 5, wherein the terminal device is further caused to:

indicate the LBT failure by a physical layer of the terminal device to a medium access control (MAC) entity of the terminal device via at least one of the following:

an exceptional LBT failure indication indicating that the LBT failure occurs due to Synchronization Signal Block (SSB) transmission or Physical Sidelink Feedback Channel (PSFCH) transmission, or

a cause value of the LBT failure comprising at least one of:

Physical Sidelink Control Channel (PSCCH) /

Physical Sidelink Shared Channel (PSSCH) transmission,

SSB transmission, or

PSFCH transmission.
The terminal device of claim 5, wherein the terminal device is further caused to:

indicate, by a physical layer of the terminal device to a MAC entity of the terminal device, a detection of the LBT failure on the resource block set; and

determine, by the MAC entity, that the resource block set for which the LBT failure is detected is not overlapped with the first resource pool.
The terminal device of any of claims 5-7, wherein the terminal device is further caused to:

determine whether a consistent LBT failure occurs for the resource block set by counting indications of the LBT failure; and

in accordance with a determination that the consistent LBT failure occurs for the resource block set, transmit a report of the consistent LBT failure to the network device if the terminal device is in a connected state.
The terminal device of any of claims 5-7, wherein the terminal device is further caused to:

in accordance with a determination that the terminal device is in an idle state or an inactive state, trigger a procedure for entering into a connected state with the network device; and

in accordance with a determination that the terminal device is in the connected state, transmit the information associated with the LBT failure to the network device.
The terminal device of claim 5, wherein the resource block set is overlapped in frequency domain with a second resource pool configured by the network device and different from the first resource pool, and the terminal device is further caused to:

count, by a MAC entity of the terminal device, indications of the LBT failure from a physical layer of the terminal device.
The terminal device of claim 10, wherein the terminal device is further caused to:

determine whether a consistent LBT failure occurs for the resource block set based on counting the indications; and

in accordance with a determination that the consistent LBT failure occurs for the resource block set, perform at least one of:

transmitting, to the network device, a report of the consistent LBT failure within the second resource pool if the terminal device is in a connected state with the network device,

excluding the second resource pool from future resource pool selection or reselection, or

performing a resource pool selection or reselection based on a number of resource block sets for which LBT failure is detected in each resource pool of a plurality of resource pools configured by the network device.
A first terminal device comprising:

a processor configured to cause the first terminal device to:

perform packet transmissions with a second terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and

in accordance with a determination that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended, transmit, to the second terminal device, information indicating the at least one suspended transmission.
The first terminal device of claim 12, wherein the information comprises at least one of:

an indication of a temporary de-activation for the at least one suspended transmission,

a counter indicating a number of transmission occasions for recovering the at least one suspended transmission,

a fourth timer indicating a time duration for recovering the at least one suspended transmission,

carrier information for recovering the at least one suspended transmission,

an indication for disabling a Hybrid Automatic Repeat reQuest (HARQ) feedback of the at least one suspended transmission, or

an indication of a HARQ feedback scheme to be used for the at least one suspended transmission.
The first terminal device of claim 12, wherein the information further indicates a cause of the suspending of the at least one transmission, and the cause comprises at least one of:

a re-evaluation of a resource reserved for the at least one transmission,

a preemption of the resource reserved for the at least one transmission, or

a configuration of the at least one transmission by a network device.
A second terminal device comprising:

a processor configured to cause the second terminal device to:

perform packet transmissions with a first terminal device based on Packet Data Convergence Protocol (PDCP) duplication; and

receive, from the first terminal device, information indicating that at least one transmission of an original packet transmission or a duplicated packet transmission is suspended.
The second terminal device of claim 15, wherein the information comprises at least one of:

an indication of a temporary de-activation for the at least one suspended transmission,

a counter indicating a number of transmission occasions for recovering the at least one suspended transmission,

a fourth timer indicating a time duration for recovering the at least one suspended transmission,

carrier information for recovering the at least one suspended transmission,

an indication for disabling a Hybrid Automatic Repeat reQuest (HARQ) feedback of the at least one suspended transmission, or

an indication of a HARQ feedback scheme to be used for the at least one suspended transmission.
The second terminal device of claim 15, wherein the information further indicates a cause of the suspending of the at least one transmission, and the cause comprises at least one of:

a re-evaluation of a resource reserved for the at least one transmission,

a preemption of the resource reserved for the at least one transmission, or

a configuration of the at least one transmission by a network device.
The second terminal device of claim 15, wherein the second terminal device is further caused to perform at least one of:

disabling a Hybrid Automatic Repeat reQuest (HARQ) feedback for the at least one suspended transmission, or

determining a HARQ feedback scheme to be used for the at least one suspended transmission.
A communication method implemented at a terminal device, comprising:

determining Listen Before Talk (LBT) failure information about at least one consistent LBT failure occurring on at least one resource block set of the terminal device; and

performing a LBT failure cancellation at least based on the LBT failure information.
A communication method implemented at a terminal device, comprising:

detecting a Listen Before Talk (LBT) failure for a resource block set associated with a sidelink communication, wherein the resource block set is not overlapped with a first resource pool being used for sidelink data transmissions and sidelink control information transmissions; and

in accordance with a determination that the LBT failure is detected, transmitting information associated with the LBT failure to a network device based on a connection state of the terminal device with the network device.