A method and terminal device that are executed by a terminal device

Abstract

According to an embodiment, a solution for sidelink is proposed. A terminal device acquires a configuration of continuous Listening-Before-Talk (LBT) failure detection for sidelink communication. The configuration indicates a condition for continuous LBT failure. The terminal device also detects continuous LBT failure for sidelink communication. If the condition is met, the terminal device performs one of the following: releasing this sidelink communication, pausing this sidelink communication, or performing continuous LBT failure recovery. This allows the terminal device to reduce power.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and more particularly to communication methods, devices, and computer-readable media.

Background Art

[0002] Several techniques have been proposed to improve communication performance. For example, device-to-device (D2D) / sidelink communication has been proposed. Sidelink is a special communication mechanism between devices without going through an eNB.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Generally, exemplary embodiments of the present disclosure provide solutions for communication.

Means for Solving the Problems

[0004] In a first aspect, a communication method is provided. The communication method includes, in a first terminal device, obtaining a setting of continuous listen before talk (LBT) failure detection indicating a condition for continuous LBT failures in sidelink communication, detecting a continuous LBT failure for the sidelink communication based on the condition, and in response to a determination that the condition is met, performing one of releasing the sidelink communication, suspending the sidelink communication, or performing continuous LBT failure recovery for the sidelink communication.

[0005] In a second embodiment, a terminal device is provided. The terminal device comprises a processing unit and a memory connected to the processing unit and storing instructions, and when an instruction is executed by the processing unit, the terminal device includes: obtaining a setting for continuous LBT fault detection indicating conditions for continuous listening before talk (LBT) faults in sidelink communication; detecting a continuous LBT fault in the sidelink communication based on the conditions; and, in response to a determination that the conditions have been met, performing one of the following: releasing the sidelink communication, suspending the sidelink communication, or performing continuous LBT fault recovery in the sidelink communication.

[0006] In a third embodiment, a computer-readable medium is provided that, when executed on at least one processor, stores instructions causing that at least one processor to perform the method described in the first or second embodiment.

[0007] Other features of this disclosure should be easily understood from the following explanation. [Brief explanation of the drawing]

[0008] The above-mentioned and other objectives, features, and advantages of this disclosure will be further clarified by describing in more detail some embodiments of this disclosure in the attached drawings.

[0009] [Figure 1A] This is a schematic diagram showing an exemplary communication environment in which the embodiments of this disclosure can be implemented. [Figure 1B] This is a schematic diagram showing an exemplary communication environment in which the embodiments of this disclosure can be implemented.

[0010] [Figure 2] This figure shows a signaling flow for communication according to some embodiments of the present disclosure.

[0011] [Figure 3] This figure shows a signaling flow for communication according to some embodiments of the present disclosure.

[0012] [Figure 4] This is a flowchart of an exemplary method according to an embodiment of the present disclosure.

[0013] [Figure 5] This is a schematic block diagram of a device suitable for implementing an embodiment of the present disclosure.

[0014] In the diagram, identical or similar reference numbers represent identical or similar elements. [Modes for carrying out the invention]

[0015] The principles of this disclosure are described here with reference to several exemplary embodiments. These embodiments are provided for illustrative purposes only and should be understood as helping those skilled in the art to understand and implement this disclosure, and should not be considered to imply any limitation on the scope of this disclosure. The disclosures described herein can be implemented in a variety of ways different from those described below.

[0016] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art.

[0017] As used herein, the term “terminal device” refers to any device having wireless or wired communication capabilities. Examples of terminal devices include user equipment (UE), personal computers, desktops, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, ultra-reliable low-latency communication (URLLC) devices, Internet of Everything (IoE) devices, machine-type communication (MTC) devices, in-vehicle devices for V2X communication where X represents pedestrians, vehicles, or infrastructure / networks, devices for integrated access and backhaul (IAB), satellite-borne or aircraft-borne vehicles within non-terrestrial networks (NTN) including high-altitude platforms (HAP) encompassing satellites and unmanned aircraft systems (UAS), extended reality (XR) devices including different types of reality such as augmented reality (AR), mixed reality (MR), and virtual reality (VR), unmanned aerial vehicles (UAVs), which are aircraft without human pilots and are commonly referred to as drones, and high-speed trains (HSTs). The “Terminal device” includes, but is not limited to, devices on a train, or image acquisition devices such as digital cameras, sensor game devices, music storage and playback devices, or internet-connected home appliances that enable wireless or wired internet access and browsing. The “Terminal device” may further have “multicast / broadcast” capabilities to support V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, wireless software distribution, group communications, and IoT applications, where public safety and mission are of paramount importance. It may also incorporate one or more Subscriber Identity Modules (SIMs), known as multi-SIMs.The term “terminal equipment” may be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or radio equipment. In the following description, the terms “terminal equipment,” “communication equipment,” “terminal,” “user equipment,” and “UE” may be used interchangeably.

[0018] Terminal devices or network devices may possess artificial intelligence (AI) or machine learning capabilities. Generally, this includes models trained on large amounts of data collected for a specific function, which can be used to predict certain information.

[0019] Terminal or network devices may operate in several frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), frequency bands greater than 100 GHz, and terahertz (THz). Furthermore, they may operate in permitted / unpermitted / shared spectrum. Terminal devices may have two or more connections to network devices under Multi-Radio Dual Connectivity (MR-DC) application scenarios. Terminal or network devices may operate in full-duplex, flexible-duplex, or cross-split-duplex modes.

[0020] Embodiments of this disclosure may be implemented, for example, in test equipment such as signal generators, signal analyzers, spectrum analyzers, network analyzers, test terminal devices, test network devices, and channel emulators.

[0021] Embodiments of the present disclosure may be implemented in accordance with any generation of communication protocols currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth-generation (6G) networks.

[0022] The term "network device" refers to a device that can provide or host a cell or coverage with which a terminal device can communicate. Examples of network devices include, but are not limited to, Node B (NodeB or NB), evolved Node B (eNodeB or eNB), next-generation Node B (gNB), transmission and reception point (TRP), remote radio unit (RRU), radio head (RH), remote radio head (RRH), IAB node, femto node, pico node, low-power nodes such as reconfigurable intelligent surface (RIS).

[0023] In one embodiment, a terminal device can be connected to a first network device and a second network device. One of the first network device and the second network device may be used as a master node, and the other may be used as a secondary node. The first network device and the second network device may use different radio access technologies (RATs). In one embodiment, the first network device may be a first RAT device, and the second network device may be a second RAT device. In one embodiment, the first RAT device is an eNB, and the second RAT device is a gNB. Information regarding different RATs may be transmitted from at least one of the first network device and the second network device to the terminal device. In one embodiment, the first information may be transmitted from the first network device to the terminal device, and the second information may be transmitted from the second network device directly or via the first network device to the terminal device. In one embodiment, information regarding the settings of the terminal device set by the second network device may be transmitted from the second network device via the first network device. Information regarding the reconfiguration of the terminal device set by the second network device may be transmitted from the second network device directly or via the first network device to the terminal device.

[0024] The communications described herein may conform to any appropriate standard, including but not limited to New Radio Access (NR), Long-Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), cdma2000, and the Global System for Mobile Communications (GSM). Furthermore, the communications may be performed in accordance with any generation of communication protocols currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.85G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G), and sixth-generation (6G) communication protocols. The technologies described herein can be used in the aforementioned wireless networks and technologies, as well as other wireless networks and technologies. Embodiments of this disclosure may be performed in accordance with any generation of communication protocols currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth-generation (6G) networks.

[0025] As used herein, the term “circuit” may mean hardware circuitry and / or combinations of hardware circuitry and software. For example, a circuit may be a combination of analog and / or digital hardware circuitry and software / firmware. In yet another example, a circuit may be any part of a hardware processor having a digital signal processor, software and one or more memories, which work together to cause a device such as a terminal or network device to perform various functions. In yet another example, a circuit may be a hardware circuit and / or a processor such as a microprocessor or a part thereof that requires software / firmware for operation, but the software may not be present if it is not required for operation. As used herein, the term “circuit” may include hardware circuitry or one or more processors alone, or parts of hardware circuitry or one or more processors and their (or their) accompanying software and / or firmware implementations.

[0026] As used herein, the singular "one" and "the foregoing" also include the plural unless explicitly indicated in the context. The term "including" and its variations should be understood as open-ended terms meaning "including, but not limited to." The term "based on" should be understood as "at least partially based on." The terms "one embodiment" and "embodiment" should be understood as "at least one embodiment." The term "another embodiment" should be understood as "at least one other embodiment." Terms such as "first," "second," etc., may refer to different or identical subjects. The following may include other explicit and implicit definitions.

[0027] In some examples, values, procedures, or devices are referred to as “best,” “lowest,” “highest,” “minimum,” “maximum,” etc. Such descriptions are intended to show that a choice can be made from many commonly used functional alternatives, and it should be understood that such a choice does not need to be better, smaller, higher, or otherwise more desirable than other choices.

[0028] As mentioned above, sidelinks have been proposed. Sidelinks support direct communication between two or more adjacent UEs without going through any network nodes, while using NR / LTE technology. The next-generation radio access network (NG-RAN) architecture can support the PC5 interface. Sidelink transmission and reception on the PC5 interface is supported when the UE is within NG-RAN coverage, regardless of the RRC state of the UE, and when the UE is outside NG-RAN coverage. NR sidelink communication can include unicast, groupcast, and broadcast. In the case of unicast, the PC5-RRC connection is a logical connection between a source Layer 2 ID and a destination Layer 2 ID pair within the access layer (AS).

[0029] Conventionally, two sidelink resource allocation modes, Mode 1 and Mode 2, are supported. In Mode 1, sidelink resource allocation is provided by the network. The NG-RAN can dynamically allocate resources to the UE via the Sidelink RNTI (SL-RNTI) on the Physical Downlink Control Channel (PDCCH) for NR sidelink communication. Furthermore, the NG-RAN can allocate sidelink resources to the UE using two types of configured sidelink authorization. Using Type 1, the RRC directly provides configured sidelink authorization only for NR sidelink communication. Using Type 2, the RRC defines the periodicity of configured sidelink authorization, and the PDCCH can signal and activate or deactivate the configured sidelink authorization. The PDCCH is directed to the Sidelink Configured Scheduling RNTI (SL-CS-RNTI) for NR sidelink communication. The currently configured sidelink authorization is used only for initial transmission.

[0030] In Mode 2, the UE determines the SL transmit resources within the resource pool. If the UE is within NG-RAN coverage, it is provided via broadcast system information or dedicated signaling; if it is outside NG-RAN coverage, it autonomously selects sidelink resources from a pre-configured resource pool. NG-RAN can dynamically allocate resources to the UE via SL-RNTI in the PDCCH for NR sidelink communication. Currently, sidelinks are only supported in the licensed band. Research is also being conducted on supporting sidelink communication in the unlicensed band. However, the unlicensed band is unstable, and a sudden increase in bandwidth traffic can lead to persistent LBT failures. If terminal equipment continues to perform sidelink communication in the unlicensed band, it will result in wasted UE power and significant traffic delays. Furthermore, it remains unclear how the configured sidelink retransmission for sidelinks will be supported, and how the received signal strength indicator (RSSI) and channel occupancy information will be obtained at the peer UE.

[0031] According to the embodiment, a solution for sidelinks is proposed. The terminal device acquires a setting for continuous listening-before-talk (LBT) fault detection. This setting indicates a condition for continuous LBT faults. The terminal device also detects continuous LBT faults for sidelink communication based on this condition. If this condition is met, the terminal device performs one of the following actions for the sidelink communication: release the sidelink communication, suspend the sidelink communication, or perform continuous LBT fault recovery for the sidelink communication. This allows the terminal device to reduce power consumption.

[0032] Figure 1A is a schematic diagram of a communication system that can implement an embodiment of the present disclosure. Communication system 100-1, which is part of a communication network, comprises a terminal device 110. The communication system also comprises terminal devices 130-1, 130-2, ..., 130-M, which can be collectively referred to as “terminal device 130”. The number N may be any suitable integer. Terminal device 110 can communicate with terminal devices 130 (e.g., terminal devices 130-1, 130-2, and 130-N), and the links between terminal devices are referred to as side links.

[0033] Communication system 100-1 further comprises a network device. In communication system 100, the network device 120 and terminal device 110 can communicate data and control information with each other. The number of terminal devices shown in Figure 1 is shown for illustrative purposes only and does not imply any limitation. Network device 120 can also communicate with terminal device 130. In this case, terminal devices 130-1, 130-2, and 130-N can be referred to as destination terminal devices / UEs. In communication system 110 shown in Figure 1A, terminal devices 110 and 130 are within the coverage of network device 120. Alternatively, in communication system 130-1 shown in Figure 1B, terminal devices 110 and 130 are outside the coverage of network device 120. In some other embodiments, one or more of the terminal devices (including terminal device 110 and terminal device 130) may be outside the coverage of network device 120, while other terminal devices may be within the coverage of network device 120.

[0034] Communication in the communication system 100 can be implemented in accordance with any suitable communication protocol, including but not limited to, cellular communication protocols such as first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G), wireless local area network communication protocols such as IEEE 802.11, and / or any other protocols currently known or to be developed in the future. Furthermore, communication may utilize any suitable wireless communication technology, including but not limited to code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplexer (FDD), time division duplexer (TDD), multi-input multiple-output (MIMO), orthogonal frequency division multiple access (OFDMA), and / or any other technologies currently known or to be developed in the future.

[0035] Embodiments of the present disclosure can be applied to any suitable scenario. For example, embodiments of the present disclosure can be implemented in NR equipment with reduced capabilities. Alternatively, embodiments of the present disclosure can be implemented in one of the following: NR multi-input multi-output (MIMO), NR sidelink enhancement, NR systems with frequencies above 52.6 GHz, extended NR operations up to 71 GHz, narrowband Internet of Things (NB-IOT) / extended machine-type communications (eMTC) on non-terrestrial networks (NTN), NTN, UE power saving enhancement, NR coverage enhancement, NB-IOT and LTE-MTC, integrated access and backhaul (IAB), NR multicast and broadcast services, or multi-radio dual connectivity enhancement.

[0036] As used herein, the term "slot" means a dynamic scheduling unit. A slot contains a predetermined number of symbols. The term "downlink (DL) subslot" may refer to a virtual subslot built upon an uplink (UL) subslot. A DL subslot may contain fewer symbols than a single DL slot. As used herein, a slot may refer to a regular slot containing a predetermined number of symbols and a subslot containing fewer symbols than that predetermined number.

[0037] Embodiments of the present disclosure are described in detail below. First, we refer to Figure 2, which shows a signaling diagram illustrating a process 200 between a terminal device and a network device according to some exemplary embodiments of the present disclosure. For illustrative purposes only, we will describe the process 200 with reference to Figure 1. The process 200 may involve the terminal device 110 and the network device 120 shown in Figure 1.

[0038] The terminal device 110 acquires the setting for continuous LBT fault detection. As used herein, the term “Listening Before Talk (LBT)” refers to a technique used in wireless communication that allows a wireless transmitter to first detect its wireless environment before it begins transmitting. LBT may be used by the device to find a network on which the wireless device is permitted to operate or to find a clear wireless channel on which it can operate. As used herein, the term “Clear Channel Assessment (CCA)” refers to a technique for evaluating RF media. CCA involves listening to RF transmissions at the physical layer, and the wireless uses two separate CCA thresholds when listening to the RF media.

[0039] The settings for continuous LBT failure detection specify the conditions for continuous LBT failures. For example, in some embodiments, the settings for continuous LBT failure detection may include a threshold for a counter for LBT failures, which determines how many continuous sidelink LBT failure events the UE considers to have detected a continuous LBT failure for a sidelink. Furthermore, the settings for continuous LBT failure detection may include a timer value for continuous sidelink LBT failure detection.

[0040] Referring to Figure 2, in some embodiments, the network device 120 may transmit a setting for continuous LBT failure detection to the terminal device 110 (2005). For example, the setting for continuous LBT failure detection may be transmitted within system information. Alternatively, the setting for continuous LBT failure detection may be transmitted within an RRC reconfiguration message.

[0041] In some other embodiments, the terminal device 110 may obtain the setting for continuous LBT fault detection from pre-configured information (2010). In this case, the terminal device 110 may obtain the setting for continuous LBT fault detection when it is outside the coverage of the network device 120.

[0042] The terminal device 110 detects a persistent LBT failure for sidelink communication (2015). In some embodiments, the terminal device 110 may detect a persistent LBT failure for each sidelink bandwidth part (BWP). Alternatively, the terminal device 110 may detect a persistent LBT failure for each sidelink resource pool.

[0043] In some embodiments, the terminal device 110 maintains one counter and one timer for continuous LBT fault detection for each sidelink BWP. In some embodiments, the terminal device 110 may count LBT fault instructions from the lower layer to the MAC layer. For example, when an LBT fault instruction is received from the lower layer, the MAC layer of the terminal device 110 may start or restart the timer and increment the counter by 1. If the counter is greater than or equal to a threshold indicated in the continuous LBT fault detection settings, it means that the conditions for a continuous LBT fault have been met. In this case, a continuous LBT fault occurs for the active SL BWP. When the timer expires, the terminal device 110 may reset the counter to 0. Alternatively, when an SL BWP is deactivated, the counter can be reset and the timer for detecting continuous LBT faults can be stopped. In some embodiments, when a continuous LBT fault is detected by the MAC layer, the MAC layer may notify the RRC layer about the continuous LBT fault.

[0044] In some embodiments, if the conditions for a continuous LBT failure are met, the terminal device 110 may release sidelink communication (2020). This allows the terminal device to stop sidelink transmission and reception to reduce power consumption when it detects a continuous LBT failure.

[0045] For example, if a persistent LBT failure is detected for one sidelink BWP, terminal device 110 may release the data radio bearers (DRBs) of all destination terminal devices or all destination terminal devices operating in that sidelink BWP. For example, terminal device 110 may release the DRBs of all destination terminal devices 130. Alternatively, if terminal devices 130-1 and 130-2 are operating in the sidelink BWP where a persistent LBT failure has been detected, terminal device 110 may release the DRBs of terminal devices 130-1 and 130-2. As used herein, the term "data radio bearer (DRB)" may refer to a bearer that transmits data between terminal devices or between terminal devices and network devices.

[0046] In other embodiments, terminal device 110 may release the service radio bearers (SRBs) of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. A persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may release the SRBs of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may release the SRBs of terminal devices 130-1 and 130-2. As used herein, the term “signaling radio bearer (SRB)” may refer to a type of radio bearer that carries signaling messages (e.g., RRC and / or non-access stratums (NAS) messages).

[0047] Alternatively, terminal device 110 may discard the sidelink communication-related settings of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. A persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may discard the sidelink communication-related settings of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, the sidelink communication-related settings of terminal devices 130-1 and 130-2 may be discarded.

[0048] Furthermore, terminal device 110 may reset the sidelink-specific MACs of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. A persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may reset the sidelink-specific MACs of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may reset the sidelink-specific MACs of terminal devices 130-1 and 130-2.

[0049] In some other embodiments, terminal device 110 may release the PC5-RRC connection for all destination terminal devices or all destination terminal devices operating in this sidelink BWP. A persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may release the PC5-RRC connection for all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may release the PC5-RRC connection for terminal devices 130-1 and 130-2. In one embodiment, RRC layer terminal device 110 may release the PC5-RRC connection for all destination terminal devices or indicate all destination terminal devices to a higher layer (e.g., PC5 sidelink layer).

[0050] Alternatively, if the conditions for a persistent LBT failure are met, terminal device 110 may temporarily suspend sidelink communication (2025). This allows the network to resolve the persistent LBT problem through another RRC reconfiguration, so there is no need to release and add PC5-RRC connections.

[0051] For example, if a persistent LBT failure is detected in one sidelink BWP, terminal device 110 may temporarily suspend the DRB of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. The persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may temporarily suspend the DRB of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may temporarily suspend the DRB of terminal devices 130-1 and 130-2.

[0052] In other embodiments, terminal device 110 may suspend the SRBs of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. A persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may suspend the SRBs of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may suspend the SRBs of terminal devices 130-1 and 130-2.

[0053] In other embodiments, terminal device 110 may suspend sidelink transmission for all destination terminal devices or for all destination terminal devices operating in this sidelink BWP. A persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may suspend sidelink transmission for all destination terminal devices 110's DRBs and SRBs. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may suspend sidelink transmission for terminal devices 130-1 and 130-2's DRBs and SRBs.

[0054] Furthermore, terminal device 110 may reset the sidelink-specific MAC addresses of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may reset the sidelink-specific MAC addresses of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may reset the sidelink-specific MAC addresses of terminal devices 130-1 and 130-2.

[0055] In other embodiments, the terminal device 110 may temporarily suspend a sidelink carrier in which the sidelink BWP is detected as a continuous LBT failure. Alternatively or further, the terminal device 110 may temporarily suspend a BWP in which a continuous LBT failure is detected.

[0056] In some other embodiments, terminal device 110 may suspend the PC5-RRC connection for all destination terminal devices or all destination terminal devices operating in this sidelink BWP. A persistent LBT failure is detected in this sidelink BWP. For example, terminal device 110 may suspend the PC5-RRC connection for all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may suspend the PC5-RRC connection for terminal devices 130-1 and 130-2. In one embodiment, RRC layer terminal device 110 may indicate to a higher layer (e.g., PC5 sidelink layer) that the PC5-RRC connection has been suspended for all destination terminal devices or all destination terminal devices operating in this sidelink BWP.

[0057] In an exemplary embodiment, terminal device 110 may notify network device 120 of a persistent LBT failure. For example, an information element (IE) or instruction may be included in an RRC message (e.g., SidelinkUEInformationNR message) to indicate a persistent LBT failure on a sidelink.

[0058] Alternatively, or further, terminal device 110 may notify network device 120 of radio link failures (RLFs) for all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may indicate a persistent LBT failure by setting sl-failure as RLF failure in the SidelinkUEInformationNR message.

[0059] In another embodiment, the terminal device 110 may transmit at least one of the following to the network device 120: sidelink BWP information or sidelink carrier information for a continuous LBT failure. The sidelink BWP information may indicate the ID of the sidelink BWP. The carrier information may indicate the frequency of the sidelink carrier.

[0060] The network device 120 may send a reset message to the terminal device 110 to reset sidelink communication (2040). The reset message may reset the sidelink carrier frequency or reset the sidelink BWP for the terminal device 110. In this case, the terminal device 110 may restart the DRB. Alternatively or further, the terminal device 110 may restart the SRB. In some embodiments, the terminal device 110 may restart sidelink transmission for both the DRB and SRB. In some embodiments, the terminal device 110 may restart the sidelink carrier. Alternatively or further, the terminal device 110 may restart the sidelink BWP. The terminal device 110 may also restart the PC5-RRC connection. In this case, the terminal device 110 may indicate the restart of the PC5-RRC connection to the higher layer, for example, the PC5 sidelink layer. This allows the network to fix the persistent LBT problem with another RRC reset, so there is no need to release and add PC5-RRC connections.

[0061] If there are no sidelink BWP or SL carriers experiencing a continuous LBT failure, terminal device 110 may release sidelink communication (2020). Alternatively, terminal device 110 may temporarily suspend sidelink communication (2025).

[0062] In another embodiment, if the conditions for a continuous LBT failure are met, the terminal device 110 may perform fault recovery (2030). This can reduce delay.

[0063] For example, terminal device 110 may be provided with a set of resources for recovery procedures via an RRC message. For example, terminal device 110 may switch to another sidelink BWP or carrier where a continuous LBT failure is not occurring. In some embodiments, terminal device 110 may release the sidelink BWP. Alternatively or further, terminal device 110 may release the sidelink carrier. In some other embodiments, terminal device 110 may deactivate the sidelink BWP. Terminal device 110 may deactivate the sidelink carrier. In this case, terminal device 110 may send information to network device 120 (2035). This information may indicate a sidelink BWP switch. Alternatively or further, this information may indicate a sidelink BWP release or deactivation. In other embodiments, this information may indicate a sidelink carrier switch. Alternatively or further, this information may indicate a sidelink carrier release or deactivation.

[0064] In some embodiments, the sidelink BWP and the uplink BWP may be the same. Alternatively, the sidelink BWP and the uplink BWP may have the same center frequency but different bandwidths. There may be a separate counter for continuous LBT fault detection on the uplink and a separate timer for continuous LBT fault detection on the uplink. In this scenario, where the sidelink BWP at least partially overlaps with the uplink BWP, if one LBT fault on the sidelink is indicated by a lower layer (e.g., the physical layer), the counter for continuous LBT detection on the uplink may be incremented by 1, and the timer for continuous LBT fault detection on the uplink may be started or restarted. Alternatively, or further, if one LBT fault on the uplink is indicated by a lower layer (e.g., the physical layer), the counter for continuous LBT detection on the sidelink may be incremented by 1, and the timer for continuous LBT detection on the sidelink may be started or restarted. This allows the counter to be shared between the Uu LBT fault on the same BWP and the LBT fault on the sidelink, thereby speeding up the triggering of continuous LBT faults.

[0065] As described above, persistent LBT failures may be detected for each sidelink resource pool. The terminal device 110 maintains one counter and one timer for persistent LBT failure detection for each sidelink resource pool. When an LBT failure instruction is received from a lower layer (e.g., the physical layer) for a resource pool, the MAC layer of the terminal device starts or restarts one timer and increments one counter corresponding to the resource pool by 1. If the counter is above a set threshold, the UE considers that a persistent LBT failure has occurred for the resource pool. When the timer expires, the counter for the resource pool is reset to 0. This allows for detection of persistent LBT failures at a finer granularity. In this case, if a persistent LBT failure is detected for the current sidelink resource pool, the terminal device 110 may release the current resource pool. Alternatively, the terminal device 110 may suspend the current resource pool. In other embodiments, the terminal device 110 may deactivate the current resource pool.

[0066] In some embodiments, if a persistent LBT failure is detected for the current sidelink resource pool, the terminal device 110 may re-select a resource pool for MAC protocol data units (PDUs) to be transmitted or retransmitted. If all resource pools are unavailable, the terminal device 110 may release the sidelink communication (2020). Alternatively, the terminal device 110 may suspend the sidelink communication (2025). In other embodiments, the terminal device 110 may deactivate the sidelink communication. The terminal device 110 may perform persistent LBT failure recovery (2030).

[0067] Network device 120 may transmit to terminal device 110 information indicating whether the configured sidelink permission retransmission is supported in the first terminal device (2050). In some embodiments, the above information may be transmitted in an RRC message. Alternatively, the above information may be transmitted in system information. In this case, if the transmission or retransmission of a MAC protocol data unit (PDU) fails, terminal device 110 may retransmit the MAC PDU to terminal device 130-1 (2055). The failed transmission of the MAC PDU may be determined based on an LBT failure indication from a lower layer (e.g., the physical layer) or based on a received negative Hybrid Automatic Retransmission Request (HARQ) feedback. Alternatively or further, if terminal device 110 does not receive HARQ feedback for the MAC PDU, terminal device 110 may retransmit the MAC PDU to terminal device 130-1 (2055). In other words, if there is no PSFCH reception during a PSFCH (Physical Sidelink Feedback Channel) reception occasion, terminal device 110 may retransmit the MAC PDU to terminal device 130-1. This allows the MAC PDU to be retransmitted using the configured sidelink permission, which is beneficial for resource usage.

[0068] In some embodiments, terminal device 110 may configure its peer UE (e.g., terminal device 130) to perform received signal strength indicator (RSSI) and channel occupancy conditions on the peer UE. Terminal device 110 may also receive measurement results from the peer UE and transmit them to network device 120. This allows the network / UE to understand the channel status of the peer UE. If channel conditions are poor, the network / UE may perform some action to improve the conditions, such as BWP or switching carriers. Further details will be explained with reference to Figure 3.

[0069] The network device 120 may transmit sidelink measurement settings to the terminal device 110 (3010). Sidelink measurement may be used for RSSI and channel occupancy measurement. In some embodiments, sidelink measurement settings may be transmitted in an RRCReconfiguration message. Alternatively, sidelink measurement settings may be transmitted in system information.

[0070] Terminal device 110 may transmit sidelink measurement settings to terminal device 130-1 (3020). Terminal device 130-1 may transmit an RRCReconfiguration sidelink completion message to terminal device 110 (3030).

[0071] Terminal device 130-1 may perform measurements based on the sidelink measurement settings (3040). Terminal device 130-1 may send a measurement report to terminal device 110 (3050). In some embodiments, measurement reports for RSSI and channel occupancy may be sent periodically. Alternatively, measurement reports may be reported based on events that occur. For example, a measurement report may be sent if the RRSI or channel occupancy exceeds a threshold. Alternatively, a measurement report may be sent if the RRSI or channel occupancy falls below a threshold. Terminal device 110 may send a measurement report to network device 120.

[0072] Figure 4 is a flowchart of an exemplary method 400 according to an embodiment of the present disclosure. Method 400 can be implemented in any suitable apparatus. For illustrative purposes only, Method 400 can be implemented in a terminal device 110 as shown in Figure 1.

[0073] In block 410, the terminal device 110 obtains a setting for continuous LBT failure detection. The setting for continuous LBT failure detection indicates a condition for continuous LBT failures. For example, in some embodiments, the setting for continuous LBT failure detection may include a threshold for a counter for LBT failures. Furthermore, the setting for continuous LBT failure detection may include a timer for this counter.

[0074] In some embodiments, the terminal device 110 may receive the setting for continuous LBT fault detection from the network device 120. For example, the setting for continuous LBT fault detection may be transmitted within the system information. Alternatively, the setting for continuous LBT fault detection may be transmitted within the RRC reconfiguration message.

[0075] In some other embodiments, the terminal device 110 may obtain the setting for continuous LBT fault detection from pre-configured information. In this case, the terminal device 110 may obtain the setting for continuous LBT fault detection when it is outside the coverage of the network device 120.

[0076] In block 420, the terminal device 110 detects a persistent LBT failure for sidelink communication. In some embodiments, the terminal device 110 may detect a persistent LBT failure for each sidelink bandwidth part (BWP). Alternatively, the terminal device 110 may detect a persistent LBT failure for each sidelink resource pool.

[0077] In some embodiments, the terminal device 110 may count LBT fault instructions from lower layers to the MAC layer. For example, when an LBT fault instruction is received from a lower layer (e.g., the physical layer), the MAC layer of the terminal device 110 may start or restart a timer and increment a counter by 1. If the counter is greater than or equal to a threshold indicated in the settings for continuous LBT fault detection, it means that the conditions for a continuous LBT fault have been met. In this case, a continuous LBT fault occurs for the active SL BWP. When the timer expires, the terminal device 110 may reset the counter to 0. Alternatively, when the SL BWP is deactivated, the counter can be reset and the timer for detecting continuous LBT faults can be stopped. In some embodiments, when a continuous LBT fault is detected by the MAC layer, the MAC layer may notify the RRC layer about the continuous LBT fault.

[0078] In some embodiments, if the conditions for a continuous LBT failure are met, the terminal device 110 may release sidelink communication. This allows the terminal device to stop sidelink transmission and reception to reduce power consumption when it detects a continuous LBT failure.

[0079] For example, if a persistent LBT failure is detected for each sidelink BWP, terminal device 110 may release the data radio bearers (DRBs) of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may release the DRBs of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may release the DRBs of terminal devices 130-1 and 130-2. As used herein, the term "data radio bearer (DRB)" may refer to a bearer that transmits data between terminal devices or between terminal devices and network devices.

[0080] In other embodiments, terminal device 110 may release the service radio bearers (SRBs) of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may release the SRBs of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may release the SRBs of terminal devices 130-1 and 130-2. As used herein, the term “signaling radio bearer (SRB)” may refer to a type of radio bearer that carries signaling messages (e.g., RRC and / or non-access stratums (NAS) messages).

[0081] Alternatively, terminal device 110 may discard the sidelink communication-related settings of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may discard the sidelink communication-related settings of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal devices 130-1 and 130-2 may discard the sidelink communication-related settings.

[0082] Furthermore, terminal device 110 may reset the sidelink-specific MAC addresses of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may reset the sidelink-specific MAC addresses of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may reset the sidelink-specific MAC addresses of terminal devices 130-1 and 130-2.

[0083] In some other embodiments, terminal device 110 may release the PC5-RRC connection for all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may release the PC5-RRC connection for all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may release the PC5-RRC connection for terminal devices 130-1 and 130-2. In one embodiment, terminal device 110 may release the PC5-RRC connection for all destination terminal devices or indicate all destination terminal devices to a higher layer (e.g., the PC5 sidelink layer).

[0084] Alternatively, if the conditions for a persistent LBT failure are met, terminal device 110 may temporarily suspend sidelink communication. This allows the network to resolve the persistent LBT problem through another RRC reconfiguration, so there is no need to release and add PC5-RRC connections.

[0085] For example, if a persistent LBT failure is detected for each sidelink BWP, terminal device 110 may temporarily suspend the DRB of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may temporarily suspend the DRB of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may temporarily suspend the DRB of terminal devices 130-1 and 130-2.

[0086] In other embodiments, terminal device 110 may suspend the SRBs of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may suspend the SRBs of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may suspend the SRBs of terminal devices 130-1 and 130-2. In some embodiments, terminal device 110 may suspend sidelink transmission for all destination terminal devices or all destination terminal devices operating in this sidelink BWP, including the DRB and SRB.

[0087] Furthermore, terminal device 110 may reset the sidelink-specific MAC addresses of all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may reset the sidelink-specific MAC addresses of all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may reset the sidelink-specific MAC addresses of terminal devices 130-1 and 130-2.

[0088] In some embodiments, the terminal device 110 may temporarily suspend the side link carrier. Alternatively, or further, the terminal device 110 may temporarily suspend the BWP.

[0089] In some other embodiments, terminal device 110 may suspend the PC5-RRC connection for all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may suspend the PC5-RRC connection for all destination terminal devices 110. Alternatively, if terminal devices 130-1 and 130-2 are operating in this sidelink BWP, terminal device 110 may suspend the PC5-RRC connection for terminal devices 130-1 and 130-2. In exemplary embodiments, terminal device 110 may indicate to the upper layer (e.g., the PC5 sidelink layer) the release of the PC5-RRC connection for all destination terminal devices or all destination terminal devices operating in this sidelink BWP, or indicate to the upper layer the suspension of the PC5-RRC connection for all destination terminal devices or all destination terminal devices operating in this sidelink BWP.

[0090] In an exemplary embodiment, terminal device 110 may notify network device 120 of a persistent LBT failure. For example, an information element (IE) or instruction may be included in the SidelinkUEInformationNR message to indicate a persistent LBT failure on a sidelink.

[0091] Alternatively, or further, terminal device 110 may notify network device 120 of radio link failures (RLFs) for all destination terminal devices or all destination terminal devices operating in this sidelink BWP. For example, terminal device 110 may set sl-failure as an RLF failure.

[0092] In another embodiment, the terminal device 110 may transmit BWP information and carrier information for a continuous LBT failure to the network device 120. The BWP information may indicate the BWP ID. The carrier information may indicate the carrier frequency.

[0093] In another embodiment, if the conditions for a continuous LBT failure are met, the terminal device 110 may perform beam failure recovery. This can reduce delay.

[0094] For example, terminal device 110 may be provided with a set of resources for the recovery procedure within BeamFailureRecoveryConfig via an RRC message. Beam fault recovery may occur by performing RACH on the best candidate beam selected during the beam fault recovery procedure. For example, terminal device 110 may switch to another sidelink BWP or carrier where no continuous LBT fault is occurring. In some embodiments, terminal device 110 may release the sidelink BWP. Alternatively or further, terminal device 110 may release the sidelink carrier. In some other embodiments, terminal device 110 may deactivate the sidelink BWP. Terminal device 110 may deactivate the sidelink carrier. In this case, terminal device 110 may send information to network device 120 (2035). This information may indicate a sidelink BWP switch. Alternatively or further, this information may indicate a sidelink BWP release or deactivation. In other embodiments, this information may indicate a sidelink carrier switch. Alternatively or further, this information may indicate the release or deactivation of the side link carrier.

[0095] In some embodiments, terminal device 110 may receive a reconfiguration message from network device 120 to reconfigure sidelink transmission. In this case, terminal device 110 may restart DRB. Alternatively or further, terminal device 110 may restart SRB. In some embodiments, terminal device 110 may restart sidelink transmission for DRB and SRB. In some embodiments, terminal device 110 may restart sidelink carrier. Alternatively or further, terminal device 110 may restart sidelink BWP. Terminal device 110 may also restart PC5-RRC connection. In this case, terminal device 110 may indicate the restart of PC5-RRC connection to higher layers, such as the MAC layer.

[0096] In some embodiments, the sidelink BWP and the uplink BWP may be the same. Alternatively, the sidelink BWP and the uplink BWP may have the same center frequency but different bandwidths. There may be a separate counter for continuous LBT fault detection on the uplink and a separate timer for continuous LBT fault detection on the uplink. In this situation, where the sidelink BWP at least partially overlaps with the uplink BWP, if an LBT fault is detected on the sidelink, the counter for continuous LBT detection on the uplink may be incremented by 1, and the timer for continuous LBT fault detection on the uplink may be started or restarted. Alternatively or further, if an LBT fault is detected on the uplink, the counter for continuous LBT detection on the sidelink may be incremented by 1, and the timer for continuous LBT detection on the sidelink may be started or restarted. This allows the counters to be shared between the Uu LBT fault on the same BWP and the LBT fault on the sidelink, thereby speeding up the triggering of continuous LBT faults.

[0097] As described above, persistent LBT failures may be detected for each sidelink resource pool. This allows for detection of persistent LBT failures at a finer granularity. In this case, if a persistent LBT failure is detected for the current sidelink resource pool, the terminal device 110 may release the current resource pool. Alternatively, the terminal device 110 may suspend the current resource pool. In another embodiment, the terminal device 110 may deactivate the current resource pool.

[0098] In some embodiments, if a persistent LBT failure is detected for the current sidelink resource pool, the terminal device 110 may re-select a different resource pool. If all resource pools are unavailable, the terminal device 110 may release the sidelink communication. Alternatively, the terminal device 110 may temporarily suspend the sidelink communication. In other embodiments, the terminal device 110 may deactivate the sidelink communication. The terminal device 110 may perform continuous LBT failure recovery.

[0099] Terminal device 110 may receive information from network device 120 indicating whether configured sidelink permission retransmission is supported in the first terminal device. In some embodiments, the above information may be transmitted in an RRC message. Alternatively, the above information may be transmitted in system information. In this case, if the transmission of the MAC protocol data unit (PDU) fails, terminal device 110 may retransmit the MAC PDU to terminal device 130-1. Alternatively or further, if terminal device 110 does not receive hybrid automatic repeat request (HARQ) feedback for the MAC PDU, terminal device 110 may retransmit the MAC PDU to terminal device 130-1. In other words, if there is no PSFCH reception in a PSFCH (Physical Sidelink Feedback Channel) reception occasion, terminal device 110 may retransmit the MAC PDU to terminal device 130-1. This allows the MAC PDU to be retransmitted using configured sidelink permission, which is beneficial for resource utilization.

[0100] In some embodiments, the terminal device 110 may configure its peer UE to perform the Received Signal Strength Indicator (RSSI) and channel occupancy conditions. The terminal device 110 can also report back the measurement results, thereby allowing the channel status of the peer UE to be understood. If the channel conditions are poor, the network / UE may perform some action to improve the conditions, such as BWP or switching carriers.

[0101] The terminal device may receive sidelink measurement settings from the network device 120. Sidelink measurement may be used for RSSI and channel occupancy measurement. In some embodiments, sidelink measurement settings may be transmitted in an RRCReconfiguration message. Alternatively, sidelink measurement settings may be transmitted in system information.

[0102] Terminal device 110 may transmit sidelink measurement settings to terminal device 130-1. Terminal device 110 may receive an RRCReconfiguration sidelink completion message from terminal device 130-1.

[0103] Terminal device 110 may receive measurement reports from terminal device 130-1. In some embodiments, measurement reports may be transmitted periodically. Alternatively, measurement reports may be reported based on events that occur. For example, a measurement report may be transmitted if the RRSI or channel occupancy exceeds a threshold. Alternatively, a measurement report may be transmitted if the RRSI or channel occupancy falls below a threshold. Terminal device 110 may transmit measurement reports to network device 120.

[0104] In some embodiments, the first terminal device comprises a circuit which acquires LBT fault detection settings indicating conditions for continuous listening before talk (LBT) faults in sidelink communication, and is configured to detect continuous LBT faults in the sidelink communication based on the conditions, and to perform one of the following actions in response to a determination that the conditions have been met: release the sidelink communication, suspend the sidelink communication, or perform continuous LBT fault recovery for the sidelink communication.

[0105] In some embodiments, the first terminal device includes a circuit configured to receive the settings from a network device via system information or radio resource control (RRC) reconfiguration, or to obtain the settings from pre-configured information.

[0106] In some embodiments, the first terminal device includes a circuit configured to detect continuous LBT failures for the sidelink communication by detecting continuous LBT failures for each sidelink bandwidth portion (BWP).

[0107] In some embodiments, the first terminal device comprises a circuit configured to reset a counter for counting LBT failures for the sidelink communication and to stop a timer for detecting the persistent LBT failure, in response to a determination that the sidelink BWP has been deactivated.

[0108] In some embodiments, the first terminal device comprises a circuit configured to increment a counter for continuous uplink LBT fault detection by 1 and to start or restart a timer for continuous uplink LBT fault detection, in response to a determination that the sidelink BWP at least partially overlaps with the uplink BWP and a determination that a sidelink LBT fault has been detected in the sidelink BWP.

[0109] In some embodiments, the first terminal device comprises a circuit configured to increment a counter for counting continuous LBT failures by 1 and to start or restart a timer for continuous LBT failure detection, in response to a determination that the sidelink BWP at least partially overlaps with the uplink BWP and that an uplink LBT failure has been detected in the uplink BWP.

[0110] In some embodiments, the first terminal device includes a circuit which releases the data radio bearers (DRBs) of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, releases the signaling radio bearers (SRBs) of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, discards the sidelink communication-related settings of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, resets the sidelink-specific MACs of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, and all destination terminal The device is configured to release the sidelink communication by at least one of the following: releasing the PC5-RRC connection for all destination terminal devices operating in the sidelink BWP; releasing the PC5-RRC connection for all destination terminal devices or notifying the upper layer of all destination terminal devices; notifying the network device of the continuous LBT failure; notifying the network device of a radio link failure (RLF) for all destination terminal devices or all destination terminal devices operating in the sidelink BWP; or transmitting BWP information and carrier information of the continuous LBT failure to the network device.

[0111] In some embodiments, the first terminal device includes a circuit which suspends the DRB of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, suspends the SRB of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, suspends sidelink transmission for the DRB and SRB of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, resets the sidelink-specific MAC of all destination terminal devices or all destination terminal devices operating in the sidelink BWP, suspends the sidelink carrier and / or the sidelink BWP, and all transmissions The sidelink communication is configured to be temporarily suspended by at least one of the following: temporarily suspending the PC5-RRC connection for the destination terminal device or all destination terminal devices operating in the sidelink BWP; indicating the temporary suspension of the PC5-RRC connection for all destination terminal devices or all destination terminal devices operating in the sidelink BWP; notifying the network device of the continuous LBT failure; notifying the network device of a radio link failure (RLF) for all destination terminal devices or all destination terminal devices operating in the sidelink BWP; or transmitting BWP information and carrier information of the continuous LBT failure to the network device.

[0112] In some embodiments, the first terminal device comprises a circuit that receives a reset message from a network device for resetting the sidelink communication and is configured to perform at least one of the following: restart the DRB, restart the SRB, restart the sidelink transmission for the DRB and the SRB, restart the sidelink carrier and / or sidelink BWP, restart the PC5-RRC connection, or indicate to the upper layer that the PC5-RRC connection has been restarted.

[0113] In some embodiments, the first terminal device comprises a circuit configured to perform the continuous LBT failure recovery by at least one of the following: switching to another sidelink BWP or carrier in which the continuous LBT failure is not occurring; releasing the sidelink BWP or sidelink carrier; or deactivating the sidelink BWP or sidelink carrier.

[0114] In some embodiments, the first terminal device includes a circuit configured to transmit to a network device information indicating at least one of the following: switching of the sidelink BWP, releasing or deactivating the sidelink BWP, switching of the sidelink carrier, or releasing or deactivating the sidelink carrier.

[0115] In some embodiments, the first terminal device comprises a circuit configured to detect the continuous LBT failure by detecting the continuous LBT failure for each sidelink resource pool.

[0116] In some embodiments, the first terminal device comprises a circuit that, in response to a decision to detect the ongoing LBT failure for the current sidelink resource pool, performs at least one of the following: releasing the current resource pool, pausing the current resource pool, or deactivating the current resource pool.

[0117] In some embodiments, the first terminal device comprises a circuit configured to re-select a different resource pool in response to a decision to detect the ongoing LBT failure for the current sidelink resource pool.

[0118] In some embodiments, the first terminal device comprises a circuit configured to perform one of the following actions in response to a determination that all resource pools are unavailable: release the sidelink communication, suspend the sidelink communication, or perform continuous LBT fault recovery for the sidelink communication.

[0119] In some embodiments, the first terminal device comprises a circuit configured to detect the persistent LBT fault for the sidelink communication by counting LBT fault indications received from lower layers in a media access control (MAC) entity.

[0120] In some embodiments, the first terminal device includes a circuit that receives information from a network device indicating whether a configured sidelink allow retransmission is supported in the first terminal device, and is configured to retransmit the MAC PDU using the configured sidelink allow in response to a determination that the configured sidelink allow retransmission is supported and a determination that the transmission of the MAC protocol data unit (PDU) failed or that no Hybrid Automatic Retransmission Request (HARQ) feedback for the MAC PDU was received.

[0121] In some embodiments, the first terminal device includes a circuit configured to receive sidelink measurement settings for sidelink received signal strength indicator (RSSI) and channel occupancy measurement from a network device, transmit the sidelink measurement settings for sidelink RSSI and channel occupancy measurement to a second terminal device, receive a measurement report for sidelink RSSI and channel occupancy measurement from the second terminal device, and transmit the measurement report for sidelink RSSI and channel occupancy measurement to the network device.

[0122] Figure 5 is a schematic block diagram of a device 500 suitable for implementing an embodiment of the present disclosure. The device 500 can be considered as another exemplary embodiment of the terminal device 110 and network device 120 shown in Figure 1. Therefore, the device 500 can be implemented in or as at least part of the terminal device 110.

[0123] As illustrated, the device 500 comprises a processor 510, a memory 520 connected to the processor 510, appropriate transmitters (TX) and receivers (RX) 540 connected to the processor 510, and a communication interface connected to the TX / RX 540. The memory 520 stores at least a portion of the program 530. The TX / RX 540 is used for bidirectional communication. The TX / RX 540 has at least one antenna to facilitate communication, although the access node referred to herein may actually have multiple antennas. The communication interface may represent any interface necessary for communication with other network elements, such as an X2 interface for bidirectional communication between eNBs, an S1 interface for communication between a mobility management entity (MME) / serving gateway (S-GW) and an eNB, an Un interface for communication between an eNB and a relay node (RN), or a Uu interface for communication between an eNB and a terminal device.

[0124] It is assumed that program 530 includes program instructions that, when executed by the associated processor 510, enable the device 500 to operate according to embodiments of the present disclosure, as described herein with reference to Figures 2 to 4. Embodiments of the present disclosure may be implemented by computer software executable by the processor 510 of the device 500, by hardware, or by a combination of software and hardware. The processor 510 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 510 and memory 520 may form a processing means 550 suitable for implementing various embodiments of the present disclosure.

[0125] Memory 520 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as non-temporary computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. Although only one memory 520 is shown in device 500, several physically different memory modules may be present in device 500. Processor 510 may be of any type suitable for a local technology network and may include, as non-limiting examples, one or more of general-purpose computers, dedicated computers, microprocessors, digital signal processors (DSPs), and processors based on multicore processor architectures. Device 500 may have multiple processors, for example, application-specific integrated circuit chips that are time-dependent to a clock that synchronizes the main processor.

[0126] Overall, various embodiments of the Disclosure may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some embodiments may be implemented in hardware, while others may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various embodiments of the Disclosure are illustrated and described using block diagrams, flowcharts, or any other pictorial representation, it should be understood that any blocks, devices, systems, techniques, or methods described herein may be implemented, in non-limiting examples, in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or any combination thereof.

[0127] This disclosure also provides at least one computer program product tangibly stored on a non-temporary computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions contained in a program module, which are executed within a device on a target real or virtual processor to perform the processes or methods described above with reference to any one of Figures 2 to 4. Generally, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform a specific task or realize a specific abstract data type. In various embodiments, the functions of program modules may be connected or separated among program modules as needed. The machine-executable instructions of a program module may be executed within a local or distributed device. In a distributed device, program modules may reside in both local and remote storage media.

[0128] Program code for performing the methods of this 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, a dedicated computer, or other programmable data processing device, and when executed by the processor or controller, the program code may implement the functions / operations specified in the flowcharts and / or block diagrams. The program code may be executed entirely on a machine, partially on a machine, as an independent software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0129] The program code described above may be implemented on a machine-readable medium, which may be any tangible medium that can contain or store programs used by or associated with an instruction execution system, device, or apparatus. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or apparatus, or any suitable combination of the aforementioned media. More specific examples of machine-readable storage media may include electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above.

[0130] While the operations have been described in a specific order, it should not be understood that, in order to obtain the desired results, these operations must be performed in the specific order shown, or in a sequential order, or that all of the described operations must be performed. In some cases, multitasking or parallel processing may be advantageous. Similarly, while some specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of this disclosure, but rather as descriptions of features that may be specific to a particular embodiment. Some features described in the context of individual embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented separately or in any suitable subcombination in multiple embodiments.

[0131] While this disclosure has been described in language specific to structural features and / or methodological behavior, it should be understood that the disclosure as defined in the attached claims is not necessarily limited to the specific features or behaviors described above. Rather, the specific features and behaviors described above are disclosed as exemplary forms of implementing the claims.

Claims

1. A method performed by a terminal device, To detect persistent listening-before-talk (LBT) failures of sidelinks in the selected first resource pool, In response to the detection of a continuous LBT failure in the side link of the selected first resource pool, the second resource pool is re-selected. A method that includes this.

2. This further includes performing multiple actions for all destinations in response to persistent LBT failures of side links in all configured resource pools, Performing the following process for each of the aforementioned recipients means that To release the Data Radio Bearer (DRB) at the aforementioned transmission destination, To release the Service Radio Bearer (SRB) at the aforementioned transmission destination, Discard the sidelink communication-related settings of the aforementioned destination. Reset the sidelink-specific MAC (Media Access Control) of the aforementioned transmission destination, and The release of the PC5-RRC connection for the aforementioned destination is indicated to the upper layer by the Radio Resource Control (RRC) layer. The method according to claim 1, including the method described in claim 1.

3. Means for detecting a continuous listening-before-talk (LBT) failure of a sidelink in a selected first resource pool, In response to the detection of a continuous LBT failure of the side link in the selected first resource pool, means for re-selecting a second resource pool, A terminal device equipped with this device.

4. The system further includes means for performing multiple actions for all destinations in response to continuous LBT failures of side links in all configured resource pools, Performing the following process for each of the aforementioned recipients means that To release the Data Radio Bearer (DRB) at the aforementioned transmission destination, To release the Service Radio Bearer (SRB) at the aforementioned transmission destination, Discard the sidelink communication-related settings of the aforementioned destination. Reset the sidelink-specific MAC (Media Access Control) of the aforementioned transmission destination, and The release of the PC5-RRC connection for the aforementioned destination is indicated to the upper layer by the Radio Resource Control (RRC) layer. The terminal device according to claim 3, including the following:

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