Methods, apparatuses, and systems for indicating transmission failures in wireless communications

Abstract

Methods, apparatuses, and systems for indicating a transmission failure in wireless communications are disclosed. In one embodiment, a method performed by a wireless communication device is disclosed. The method includes obtaining, by a first layer module of the wireless communication device, an indication from a second layer module of the wireless communication device. The first layer module is configured to perform a procedure at a first layer. The second layer module is configured to perform a procedure at a second layer different from the first layer. The indication indicates whether there is a transmission failure of the wireless communication device at the second layer.

Description

Technical Field

[0001] This disclosure relates generally to wireless communication, and more specifically to methods, apparatus, and systems for indicating transmission failures in wireless communication. Background Technology

[0002] Fourth-generation (4G) Long-Term Evolution (LTE) or LTE-Advanced (LTE-A) and fifth-generation (5G) mobile communication technologies face increasing demands. As the number of digital data applications and services continues to surge, the demands and challenges on network resources and operators will continue to increase. The utilization of licensed radio spectrum (or simply spectrum) is nearing saturation. Furthermore, using licensed spectrum can incur licensing costs for operators. For some areas with dedicated network deployments, when moving to handle larger volumes of spectrum, the efficient use of unlicensed spectrum with wider bandwidth (e.g., 80 or 100 MHz) can reduce implementation complexity for both networks and terminals (e.g., user equipment or UEs) compared to carriers with smaller bandwidths.

[0003] In unlicensed spectrum, a listen-before-talk (LBT) check is performed before transmission, involving clear channel assessment (CCA). CCA uses at least energy detection to determine the presence or absence of other signals on the channel, thus determining whether the channel is occupied or idle. If the channel is occupied, the UE needs to wait for a period of time before the next LBT. If the channel is idle, the UE can transmit data. Due to the opportunistic nature of this process, the UE may not be able to transmit in a timely manner, may be temporarily unable to transmit, or may not even have the opportunity to transmit. For unlicensed spectrum, if transmission cannot be performed at the physical layer, it may affect one or more processes at higher layers. For example, some procedures may not be terminated.

[0004] Therefore, existing systems and methods for handling transmission failures in wireless communication are not entirely satisfactory. Summary of the Invention

[0005] The exemplary embodiments disclosed herein relate to solving one or more problems presented in the prior art, and provide additional features that will become apparent when taken in conjunction with the accompanying drawings and the following detailed description. Exemplary systems, methods, apparatuses, and computer program products are disclosed herein according to various embodiments. However, it should be understood that these embodiments are presented by way of example and not limitation, and that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure, as will be apparent to those skilled in the art who have read this disclosure.

[0006] In one embodiment, a method performed by a wireless communication device is disclosed. The method includes: obtaining an instruction from a second-layer module of the wireless communication device by a first-layer module of the wireless communication device. The first-layer module is configured to perform a process at a first layer. The second-layer module is configured to perform a process at a second layer, different from the first layer. The instruction indicates whether a transmission failure of the wireless communication device exists at the second layer.

[0007] In another embodiment, a method performed by a wireless communication device is disclosed. The method includes: a first-layer module of the wireless communication device performing wireless transmission of a message at a first layer; and the first-layer module sending an indication to a second-layer module of the wireless communication device. The first-layer module is configured to perform the process at the first layer. The second-layer module is configured to perform the process at a second layer different from the first layer. The indication indicates whether there is a transmission failure of the transmitted message at the first layer.

[0008] In another embodiment, a method performed by a wireless communication device is disclosed. The method includes: obtaining an instruction from a second layer module of the wireless communication device by a first layer module of the wireless communication device. The first layer module is configured to perform a process at a first layer. The second layer module is configured to perform a process at a second layer, different from the first layer. The instruction indicates a transmission failure problem at a third layer, different from the first and second layers.

[0009] In different embodiments, wireless communication devices configured to perform the methods disclosed in some embodiments are disclosed.

[0010] In yet another embodiment, a non-transitory computer-readable medium is disclosed having stored thereon computer-executable instructions for performing the methods disclosed in some embodiments. Attached Figure Description

[0011] Various exemplary embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. The drawings are provided for illustrative purposes only and merely depict exemplary embodiments of the present disclosure to aid the reader's understanding. Therefore, the drawings should not be considered as limitations on the breadth, scope, or applicability of the present disclosure. It should be noted that these drawings are not necessarily drawn to scale for clarity and ease of explanation.

[0012] Figure 1 An exemplary communication network is shown, in which the techniques disclosed herein may be implemented according to embodiments of the present disclosure.

[0013] Figure 2 A block diagram of a user equipment (UE) according to some embodiments of the present disclosure is shown.

[0014] Figure 3 Detailed block diagrams of several modules in a UE according to some embodiments of the present disclosure are shown.

[0015] Figure 4 A flowchart is shown of a method performed by a UE to indicate a transmission failure according to some embodiments of the present disclosure.

[0016] Figure 5 An exemplary control plane protocol stack in a 5G system on the UE and network side is illustrated according to some embodiments of the present disclosure. Detailed Implementation

[0017] Various exemplary embodiments of this disclosure are described below with reference to the accompanying drawings to enable those skilled in the art to make and use this disclosure. As will be apparent to those skilled in the art, various changes or modifications to the examples described herein can be made after reading this disclosure without departing from its scope. Therefore, this disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the specific order and / or hierarchy of steps in the methods disclosed herein are merely exemplary methods. Based on design preferences, the specific order or hierarchy of steps in the disclosed methods or processes may be rearranged while remaining within the scope of this disclosure. Therefore, those skilled in the art will understand that the methods and techniques disclosed herein present various steps or actions in a sample order, and this disclosure is not limited to the specific order or hierarchy presented, unless otherwise expressly stated.

[0018] A typical wireless communication network includes one or more base stations (usually referred to as "BS") that each provide geographical wireless coverage, and one or more wireless user equipment devices (usually referred to as "UE") that can transmit and receive data within the wireless coverage area. In a wireless communication network, the BS and UE can communicate with each other via communication links, such as via downlink radio frames from the BS to the UE or via uplink radio frames from the UE to the BS.

[0019] UE transmissions may be blocked for various reasons, such as Listen-After-Speak (LBT) failures in unlicensed spectrum, power backoff, and conflicts with ultra-reliable low-latency communication (URLLC) services. Once transmission is blocked at the physical layer, it may affect processes in one or more upper layers. To address these issues, this teaching discloses systems and methods for notifying upper layers of unified instructions.

[0020] Furthermore, when transmission is blocked in the lower layer, a transmission failure indication is notified to the intermediate layer, which is below the upper layer and above the lower layer (e.g., the physical layer). The number of failures can be counted in the intermediate layer. In one embodiment, the number of transmission failures is counted regardless of whether the failures are consecutive or discontinuous. In another embodiment, only consecutive or continuous transmission failures are counted. In yet another embodiment, both a timer and a counter are used. When a transmission failure indication is received, the counter increments by 1, and the timer starts or restarts. When the timer expires, the counter is reset. In one embodiment, when the counter reaches a threshold, a transmission failure problem can be indicated to the upper layer. When the upper layer receives it, it can declare a radio link failure (RLF).

[0021] As used herein, the term "layer" refers to an abstraction layer in a hierarchical model (such as the Open Systems Interconnection (OSI) model) that divides a communication system into abstraction layers. A layer serves the next higher layer above it, and is served by the next lower layer below it.

[0022] In various embodiments, the BS in this disclosure may be referred to as the network side and may include or be implemented as a next-generation node B (gNB), an E-UTRAN node B (eBN), a transmit / receive point (TRP), an access point (AP), etc.; while the UE in this disclosure may be referred to as a terminal and may include or be implemented as a mobile station (MS), a station (STA), etc. According to various embodiments of this disclosure, the BS and UE may be described herein as non-limiting examples of a "wireless communication node" and a "wireless communication device" that can practice the methods disclosed herein and are capable of wireless and / or wired communication.

[0023] Figure 1 An exemplary communication network 100, according to embodiments of the present disclosure, in which the techniques disclosed herein may be implemented. For example... Figure 1 As shown, the exemplary communication network 100 includes a base station (BS) 101 and a plurality of UEs, UE 1 110, UE 2 120...UE 3 130, wherein the BS 101 can communicate with the UEs according to a radio protocol. The BS 101 and the UEs (e.g., UE 1 110) can communicate with each other in licensed or unlicensed spectrum.

[0024] In some countries and regions, there are corresponding regulatory policies for the use of unlicensed spectrum. For example, before transmitting data on an unlicensed carrier, the UE must perform Listen-Before-Speak (LBT), also known as Clear Channel Assessment (CCA). Therefore, only devices or UEs that support LBT can transmit data on unlicensed carriers. Under NR licensed carriers, the SS / PBCH block (Synchronization Signal / Physical Broadcast Channel Block, abbreviated as SSB) has cell search, synchronization, and measurement functions. Due to the special nature of unlicensed carriers, such as the need to perform LBT before transmitting data, the transmission of the SS / PBCH block and / or discovery signal faces uncertainty. In this situation, when the UE encounters a transmission failure at the physical (PHY) layer (e.g., due to LBT failure), the UE can indicate the transmission failure to its media access control (MAC) layer, which is above the PHY layer. Some statistics can be calculated at the MAC layer to determine whether a radio link failure (RLF) should be declared at the radio resource control (RRC) layer.

[0025] Figure 2 A block diagram of a user equipment (UE) 200 according to some embodiments of the present disclosure is shown. UE 200 is an example of a device that can be configured to implement the various methods described herein. Figure 2As shown, UE 200 includes housing 240, which contains system clock 202, processor 204, memory 206, transceiver 210 including transmitter 212 and receiver 214, power module 208, physical layer module 260, MAC layer module 270 and RRC layer module 280.

[0026] In this embodiment, the system clock 202 provides a timing signal to the processor 204 to control the timing of all operations of the UE 200. The processor 204 controls the overall operation of the UE 200 and may include one or more processing circuits or modules, such as any combination of a central processing unit (CPU) and / or a general-purpose microprocessor, microcontroller, digital signal processor (DSP), field-programmable gate array (FPGA), programmable logic device (PLD), controller, state machine, gating logic, discrete hardware components, dedicated hardware finite state machine, or any other suitable circuit, device, and / or structure capable of performing calculations or other data manipulations.

[0027] Memory 206 (which may include read-only memory (ROM) and random access memory (RAM)) provides instructions and data to processor 204. A portion of memory 206 may also include non-volatile random access memory (NVRAM). Processor 204 typically performs logical and arithmetic operations based on program instructions stored in memory 206. Instructions stored in memory 206 (also referred to as software) can be executed by processor 204 to perform the methods described herein. Processor 204 and memory 206 together form a processing system that stores and executes software. As used herein, “software” means any type of instructions that can configure a machine or device to perform one or more desired functions or processes, whether it refers to software, firmware, middleware, microcode, etc. Instructions may include code (e.g., in source code format, binary code format, executable code format, or any other suitable code format). When executed by one or more processors, these instructions cause the processing system to perform the various functions described herein.

[0028] Transceiver 210, including transmitter 212 and receiver 214, allows UE 200 to transmit and receive data from remote devices (e.g., BS or another UE). Antenna 250 is typically attached to housing 240 and electrically coupled to transceiver 210. In various embodiments, UE 200 includes (not shown) multiple transmitters, multiple receivers, and multiple transceivers. In one embodiment, antenna 250 is replaced by a multi-antenna array 250, which can form multiple beams, each pointing in a different direction. Transmitter 212 can be configured to wirelessly transmit packets with different packet types or functions, such packets being generated by processor 204. Similarly, receiver 214 is configured to receive packets with different packet types or functions, and processor 204 is configured to process packets with multiple different packet types. For example, processor 204 can be configured to determine the type of packet and process the packet and / or its fields accordingly.

[0029] In wireless communication, UE 200 can perform wireless transmission of messages at the physical layer via its physical layer module 260. Physical layer module 260 can transmit an indication to MAC layer module 270 to indicate whether a transmission failure has occurred at the physical layer. Physical layer module 260 is configured to perform procedures at the physical layer. MAC layer module 270 is configured to perform procedures at the MAC layer, which is above the physical layer. According to various embodiments, the transmission failure is due to at least one of the following: Listen-After-Speak (LBT) failure in unlicensed spectrum; power backoff; and conflict with Ultra-Reliable Low-Latency Communication (URLLC) services.

[0030] After receiving an indication from the physical layer module 260, the MAC layer module 270 can analyze the indication to determine if a transmission failure exists at the physical layer. The MAC layer module 270 can calculate statistics related to the physical layer transmission failure, for example, based on counters and / or timers, to determine whether to indicate a failure problem to the RRC layer module 280.

[0031] When an indication of a transmission failure is received from the MAC layer module 270, the RRC layer module 280 can declare a Radio Link Failure (RLF). The RRC layer module 280 is configured to perform procedures at the RRC layer, which is above the MAC layer. According to various embodiments, additional modules operating at other layers may be present in the UE 200. (See also...) Figure 3 Detailed descriptions are provided for each of the physical layer module 260, MAC layer module 270, and RRC layer module 280.

[0032] The power module 208 may include a power source (such as one or more batteries) and a power regulator to supply power to... Figure 2Each of the modules described above provides regulated power. In some embodiments, if the UE200 is coupled to a dedicated external power source (e.g., a wall outlet), the power module 208 may include a transformer and a power conditioner.

[0033] The various modules discussed above are coupled together via bus system 230. In addition to the data bus, bus system 230 may include a data bus and, for example, a power bus, a control signal bus, and / or a status signal bus. It should be understood that the modules of UE 200 can be operatively coupled to each other using any suitable technology and medium.

[0034] Despite Figure 2 Multiple separate modules or components are shown, but those skilled in the art will understand that one or more of the modules can be combined or implemented together. For example, processor 204 can implement not only the functionality described above with respect to processor 204, but also the functionality described above with respect to MAC layer module 270. Conversely, Figure 2 Each of the modules shown can be implemented using multiple separate components or elements.

[0035] Figure 3 Detailed block diagrams of several modules in a UE according to some embodiments of the present disclosure are shown. Figure 3 It shows Figure 2 Exemplary internal components of the physical layer module 260, MAC layer module 270, and RRC layer module 280 of UE 200. (Example...) Figure 3 As shown, the physical layer module 260 in this example includes an autonomous message generator 361, a transmission failure generator 362, and a message transmission controller 363. The MAC layer module 270 in this example includes an indicator analyzer 371, a message transmission command unit 372, a counter controller 373, a timer controller 374, and a failure problem indicator 375. The RRC layer module 280 in this example includes a radio link failure declarer 381. According to various embodiments, each of the physical layer module 260, MAC layer module 270, and RRC layer module 280 may include one or more additional components, and each component of the physical layer module 260, MAC layer module 270, and RRC layer module 280 may be optional. Figure 3 The various modules shown are coupled together and coupled to bus system 230. Figure 2 The components shown in the image.

[0036] The message transmission controller 363 can perform wireless transmission of messages at the physical layer via the transmitter 212. In one embodiment, the message transmission controller 363 obtains instructions from the MAC layer module 270 for transmitting messages at the physical layer. In another embodiment, the autonomous message generator 361 autonomously generates messages and transmits them to the message transmission controller 363 for transmission at the physical layer. The message may include information about at least one of the following: a preamble; a protocol data unit (PDU); and a scheduling request (SR).

[0037] In this example, the transmission failure generator 362 can generate a transmission failure indication and send it to the MAC layer module 270 to indicate whether a transmission failure of the message has occurred at the physical layer. In one embodiment, the indication is generated and sent only if a transmission failure occurs, so that the MAC layer module 270 can know that the transmission has failed if it receives the indication within a predetermined time, and know that the transmission has succeeded if it does not receive the indication within the predetermined time.

[0038] In this example, the indicator analyzer 371 can obtain an indication from the physical layer module 260 and analyze the indication to determine whether there is a transmission failure of the UE 200 at the physical layer. In this example, the message transmission commander 372 can instruct the physical layer module 260 to transmit a message at the physical layer, where a transmission failure is a failure to transmit a message at the physical layer. In one embodiment, a transmission failure is a failure to transmit a message autonomously generated by the physical layer module 260 at the physical layer. The message may include information about at least one of the following: a preamble; a protocol data unit (PDU); and a scheduling request (SR).

[0039] In one embodiment, the indicator analyzer 371 determines, based on the indication, that a UE transmission failure exists at the physical layer and notifies the counter controller 373 of the failure. In response to the determination by the indicator analyzer 371, the counter controller 373 can then increment the MAC layer counter by 1.

[0040] In one embodiment, the indicator analyzer 371 also notifies the timer controller 374 of a failure. In response to the confirmation from the indicator analyzer 371, the timer controller 374 can then restart the timer at the MAC layer. In response to the timer expiring, the timer controller 374 notifies the counter controller 373 of the timer expiring status, and the counter controller 373 can reset the counter at the MAC layer in response to the timer expiring.

[0041] In one embodiment, in response to a determination by the indicator analyzer 371, the timer controller 374 may start a timer that is not running at the MAC layer. In response to a timer expiration, the timer controller 374 notifies the counter controller 373 of the timer expiration, and the counter controller 373 may reset the counter at the MAC layer in response to the timer expiration.

[0042] In one embodiment, the counter controller 373 determines and notifies the failure problem indicator 375 that the counter has reached a predetermined threshold. The failure problem indicator 375 can then generate an indication and send it to the RRC layer module 280 to indicate a transmission failure problem at the physical layer and / or MAC layer.

[0043] In another embodiment, the indicator analyzer 371 determines, based on the indication, that no transmission failures have occurred at the physical layer within a predetermined time period related to message transmission, and notifies the counter controller 373 of this determination. In response to the determination by the indicator analyzer 371, the counter controller 373 can then reset the counter at the MAC layer. The counter is used to count transmission failures at the physical layer.

[0044] In another embodiment, the indicator analyzer 371 determines a failure to transmit a message at the physical layer based on the indicator and notifies the counter controller 373 of the failure. The counter controller 373 can then increment the counter associated with the message at the MAC layer by 1 in response to the determination by the indicator analyzer 371. That is, there may be multiple counters, each corresponding to a different type of message transmission. After the counter controller 373 determines and notifies the failure problem indicator 375 that the counter has reached a predetermined threshold associated with the message, the failure problem indicator 375 can then generate an indication and send it to the RRC layer module 280 to indicate a transmission failure associated with the message at the physical layer and / or MAC layer.

[0045] In another embodiment, the indicator analyzer 371 determines, based on the indication, that a transmission scheduling request (SR) has failed at the physical layer and notifies the timer controller 374 of the failure. In response to the determination by the indicator analyzer 371, the timer controller 374 can then stop the timer currently running at the physical layer and associated with the SR transmission. Since the timer is stopped, the timer controller 374 can notify the physical layer module 260 to retransmit the scheduling request (SR) at the physical layer at the next available SR transmission time, pre-configured and independent of the timer.

[0046] In another embodiment, the indicator analyzer 371 determines, based on the indication, that a transmission scheduling request (SR) has been successfully transmitted at the physical layer, and notifies the counter controller 373 and the timer controller 374 of any failure. The counter controller 373 can then increment the counter associated with the SR at the MAC layer by 1 in response to the determination by the indicator analyzer 371. In response to the determination by the indicator analyzer 371, the timer controller 374 can restart the timer associated with the SR transmission at the MAC layer. In response to the timer expiring, the timer controller 374 can notify the physical layer module 260 to retransmit the scheduling request (SR) at the physical layer.

[0047] In this example, the wireless link failure declarer 381 is configured to receive an indication from the MAC layer module 270 and analyze the indication to determine transmission failure issues at the physical and MAC layers. Based on the indication of the transmission failure issue, the wireless link failure declarer 381 can declare a wireless link failure (RLF).

[0048] Figure 4 The following are some embodiments of the UE (e.g.) according to the present disclosure. Figure 2 The flowchart illustrates a method 400 executed by UE 200 to indicate a transmission failure. At operation 402, the UE performs radio transmission of a message at the first layer (e.g., physical layer) via its first-layer module (e.g., physical layer module 260). At operation 404, an indication is sent from the UE's first-layer module to a second-layer module (e.g., MAC layer module 270) to indicate whether a transmission failure has occurred at the first layer. At operation 406, it is determined whether a transmission failure was received by the second-layer module within a predetermined time. If not, the process proceeds to operation 408 to reset the failure counter at the second layer. Otherwise, if a transmission failure was received by the second-layer module within the predetermined time, the failure counter at the second layer is incremented by 1 at operation 410.

[0049] Then, at operation 412, it is determined whether the counter has reached a predetermined threshold. If so, the process proceeds to operation 414 to indicate a transmission failure to a Layer 3 module (e.g., RRC layer module 280), which can declare a Radio Link Failure (RLF) at operation 415. If not, the process proceeds to operation 416 to restart the timer at Layer 2. When the time expires, the failure counter is reset at operation 418.

[0050] Figure 5Exemplary control plane protocol stacks in a 5G system's UE and network side (e.g., 5G base stations and mobility management entities (MMEs)) according to some embodiments of this disclosure are illustrated. In this example, the UE 510 includes a non-access stratum (NAS) layer, a radio resource control (RRC) layer, a data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a media access control (MAC) layer, and a physical (PHY) layer. The 5G BS 520 includes the RRC layer, PDCP layer, RLC layer, MAC layer, and PHY layer, and the MME includes the NAS layer.

[0051] The PDCP layer sits above the RLC layer, which in turn sits above the MAC layer, which in turn sits above the PHY layer. Similarly, the RRC layer sits above the PDCP layer, which sits above the RLC layer, which in turn sits above the MAC layer. There are numerous signaling procedures between the UE and the network side, including Layer 3 signaling procedures (such as RRC and NAS signaling procedures) and Layer 2 signaling procedures (such as MAC control signaling or RLC-related signaling procedures, such as RLC reset procedures). Timely execution of such control plane (e.g., RRC) or user plane (e.g., RLC or MAC) signaling procedures is a key factor in achieving fast and reliable communication.

[0052] Different embodiments of this disclosure will now be described in detail below. Note that the features of the embodiments and examples in this disclosure can be combined with each other in any way without conflict.

[0053] In the first embodiment, transmission may be blocked for various reasons, such as LBT failure in unlicensed spectrum, power backoff, or conflicts with URLLC services. In some cases, transmission blockage may affect the processes of other layers. Therefore, other layers need to know the transmission result. According to this embodiment, an instruction is sent to other layers so that they can perform certain actions based on the instruction.

[0054] According to the second embodiment, in unlicensed spectrum, transmissions may be blocked due to LBT failures, such as RS transmissions, each message transmission in the RACH procedure, and PUSCH transmissions. When a transmission fails, it may affect the processes of other layers (e.g., the MAC layer). For the random access channel (RACH) procedure, when the current preamble transmission is blocked due to an LBT failure, the power ramping counter does not increment. Therefore, the physical layer needs to notify the MAC layer of the transmission failure so that the power ramping counter does not increment in the next preamble transmission, thus avoiding unnecessary power increases for retransmission.

[0055] Furthermore, for the SR procedure, when SR transmission is blocked due to LBT failure, the disable timer is not started at the MAC layer. Therefore, a transmission failure indication should be sent to the MAC layer so that the disable timer is not started or is stopped, thus avoiding unnecessary waiting time for retransmission.

[0056] For Physical Uplink Shared Channel (PUSCH) transmissions, transmission can be blocked due to LBT failures, especially for configured licensed transmissions. If a MAC Protocol Data Unit (PDU) is indicated to the Physical Layer, a timer will be started at the MAC Layer. If transmission is blocked due to LBT failure, the UE will wait for the timer to expire before executing the next transmission, which increases transmission latency. In this case, the MAC Layer should be notified of the transmission indication so that it can stop the timer and execute the next transmission as soon as possible.

[0057] Therefore, for SR procedures, RACH procedures, and PUSCH transmissions, a transmission failure indication can be sent to the MAC layer, allowing the UE to perform other operations based on the indication, thereby improving system performance.

[0058] According to the third embodiment, a transmission failure counter is introduced. When transmission is blocked in the lower layer, a transmission failure indication is sent to the intermediate layer. The transmission failure counter is then incremented by 1. When the transmission failure counter reaches a threshold, a failure should be indicated to the upper layer.

[0059] For the SR procedure, RACH procedure, and transmission process in the MAC layer, the transmission failure counter can be a unified counter used for these procedures. The transmission counter is not limited to consecutive transmission failures. For example, the counter increments as soon as a received transmission fails. Taking the RACH procedure as an example, when the RACH procedure is triggered, the following steps can be performed.

[0060] Step 1: The MAC layer selects a preamble and instructs the physical layer to do so.

[0061] Step 2: The physical layer performs LBT before transmission.

[0062] Step 3: If LBT fails, the physical layer notifies the MAC layer of a transmission failure indication.

[0063] Step 4: When the MAC layer receives a transmission failure indication, the transmission failure counter increments by 1; otherwise, the counter does not increment.

[0064] Step 5: If the transmission failure counter reaches the threshold, it should indicate a transmission failure problem to the RRC layer.

[0065] Step 6: When the RRC layer receives a transmission failure problem, it can declare a radio link failure (RLF).

[0066] Besides transmissions indicated by the MAC layer, there are also some message transmissions that do not require MAC layer indication and are transmitted directly at the physical layer. Examples include HARQ feedback, channel state information (CSI), and sounding reference signal (SRS) transmitted via the Physical Uplink Control Channel (PUCCH). For these messages, if a transmission failure indication is not sent to the MAC layer when transmission is blocked, the transmission failure counter is only used for statistics on transmission failures of messages indicated by the MAC layer. If a transmission failure indication is sent to the MAC layer, the transmission failure counter will increment once the indication is received. These detailed steps are described below.

[0067] Step 1: HARQ feedback / CSI needs to be transmitted, and only PUCCH resources can be used for transmission in the physical layer.

[0068] Step 2: If LBT fails, the physical layer notifies the MAC layer of a transmission failure indication.

[0069] Step 3: When the MAC layer receives a transmission failure indication, the transmission failure counter increments by 1; otherwise, the counter does not increment.

[0070] Step 4: If the transmission failure counter reaches the threshold, it should indicate a transmission failure problem to the RRC layer.

[0071] Step 5: When the RRC layer receives a transmission failure, it can declare an RLF.

[0072] According to the fourth embodiment, a transmission failure counter is introduced. When transmission is blocked in the lower layer, a transmission failure indication is sent to the intermediate layer. The transmission failure counter is then incremented by 1. When the transmission failure counter reaches a threshold, a failure should be indicated to the upper layer.

[0073] For each procedure (such as the SR procedure, RACH procedure, and PUSCH transport procedure), the transport failure counter can be a unified counter used for these procedures. This document counts the number of consecutive transport failures. Once a transport has been indicated to a lower layer and no transport failure indication has been received, the transport failure counter is reset; otherwise, it is incremented by 1. When the transport failure counter reaches a threshold, the intermediate layer should indicate the transport failure problem to the upper layer. Taking the RACH procedure as an example, when the RACH procedure is triggered, the following steps can be performed.

[0074] Step 1: The MAC layer selects a preamble and instructs the physical layer to do so.

[0075] Step 2: The physical layer performs LBT before transmission.

[0076] Step 3: If LBT fails, the physical layer notifies the MAC layer of a transmission failure indication.

[0077] Step 4: When the MAC layer receives a transmission failure indication, the transmission failure counter is incremented by 1; otherwise, when the message transmission ends, the counter will be reset if there is no received indication.

[0078] Step 5: If the transmission failure counter reaches the threshold, the MAC layer should indicate the transmission failure problem to the RRC layer.

[0079] Step 6: When the RRC layer receives a transmission failure, it can declare an RLF.

[0080] According to the fifth embodiment, when transmission is blocked in the lower layer, a transmission failure indication is notified to the intermediate layer. The transmission failure counter is then incremented by 1. When the transmission failure counter reaches a threshold, the failure should be indicated to the upper layer. For each procedure (such as the SR procedure, RACH procedure, and PUSCH transmission procedure), the transmission failure counter can be a unified counter used for these procedures. This document uses both a timer and a counter; when a transmission failure indication is received, the timer is started or restarted, and the transmission failure counter is incremented by 1. When no transmission failure indication is received within the timer, the transmission counter is reset. When the transmission failure counter reaches a threshold, the intermediate layer should indicate the transmission failure to the upper layer. Taking the RACH procedure as an example, when the RACH procedure is triggered, the following steps can be performed.

[0081] Step 1: The MAC layer selects a preamble and instructs the physical layer to do so.

[0082] Step 2: The physical layer performs LBT before transmission.

[0083] Step 3: If LBT fails, the physical layer notifies the MAC layer of a transmission failure indication.

[0084] Step 4: When the MAC layer receives a transmission failure indication, the transmission failure counter increments by 1, and the timer starts or restarts. When the timer expires, the transmission counter is reset.

[0085] Step 5: If the transmission failure counter reaches the threshold, the MAC layer should indicate the transmission failure problem to the RRC layer.

[0086] Step 6: When the RRC layer receives a transmission failure, it can declare an RLF.

[0087] Besides transmissions indicated by the MAC layer, there are also some message transmissions that do not require MAC layer indication and are transmitted directly at the physical layer, such as HARQ feedback and CSI / SRS transmitted via PUCCH. For these messages, if a transmission failure indication is not sent to the MAC layer when transmission is blocked, the transmission failure counter is only used for statistics on transmission failures of messages indicated by the MAC layer. If a transmission failure indication is sent to the MAC layer, the transmission failure counter will increment once the indication is received. These detailed steps are described below.

[0088] Step 1: HARQ feedback / CSI needs to be transmitted, and only PUCCH resources can be used for transmission in the physical layer.

[0089] Step 2: If LBT fails, the physical layer notifies the MAC layer of a transmission failure indication.

[0090] Step 3: When the MAC layer receives a transmission failure indication, the transmission failure counter increments by 1, and the timer starts or restarts. When the timer expires, the transmission counter is reset.

[0091] Step 4: If the transmission failure counter reaches the threshold, it should indicate a transmission failure problem to the RRC layer.

[0092] Step 5: When the RRC layer receives a transmission failure, it can declare an RLF.

[0093] According to the sixth embodiment, for PUSCH, the UE autonomously transmits PUSCH using the configured authorized resources. When the channel occupancy rate is very high, LBT failure always occurs, causing transmission attempts to be made. To terminate the transmission attempt procedure, a counter can be introduced. When transmission fails due to LBT, a failure indication is notified to the MAC layer. When the MAC layer receives the indication, the counter is incremented by 1. The failure indication can be continuous or discontinuous. The detailed procedure can be described as follows.

[0094] Step 1: The MAC layer indicates the MAC PDU to the physical layer.

[0095] Step 2: The physical layer performs LBT before transmission.

[0096] Step 3: If LBT fails, notify the MAC layer of the failure indication.

[0097] Step 4: The MAC layer receives the instruction and increments the counter by 1.

[0098] Step 5: If the counter reaches the threshold, indicate a transmission failure to the RRC layer.

[0099] Step 6: When the RRC layer receives a transmission failure problem, it declares an RLF.

[0100] According to the seventh embodiment, for PUSCH, the UE autonomously transmits PUSCH via the configured authorized resources. When the channel occupancy rate is very high, LBT failure always occurs, causing transmission attempts to be made. To terminate the transmission attempt procedure, both a counter and a timer can be introduced. When transmission fails due to LBT, a failure indication is notified to the MAC layer. When the MAC layer receives the indication within the timer, the counter increments by 1 and the timer starts or restarts. When the timer expires and no failure indication is received, the counter is reset. The detailed procedure can be described as follows.

[0101] Step 1: The MAC layer indicates the MAC PDU to the physical layer.

[0102] Step 2: The physical layer performs LBT before transmission.

[0103] Step 3: If LBT fails, notify the MAC layer of the failure indication.

[0104] Step 4: The MAC layer receives an indication within the timer, increments the counter by 1, and starts or restarts the timer. When the timer expires and no indication is received, the counter is reset.

[0105] Step 5: If the counter reaches the threshold, indicate a transmission failure to the RRC layer.

[0106] Step 6: When the RRC layer receives a transmission failure problem, it declares an RLF.

[0107] According to the eighth embodiment, for unlicensed spectrum, SR is not transmitted due to LBT failure. In this case, the SR disable timer should not be started. SR transmission should be performed as soon as possible at the next available SR transmission opportunity. An indication should then be sent to the MAC layer. If an LBT failure indication is sent to the MAC layer, the UE can stop the timer. Furthermore, the SR counter should not be incremented to avoid unnecessary RLF. When an LBT failure indication is sent to the MAC layer, the processing of the SR procedure in the MAC layer can be modified as follows.

[0108] For the SR configuration corresponding to the pending SR: If a notification of transmission failure has been received from the lower layer and if the sr-ProhibitTimer is running, stop the sr-ProhibitTimer. Otherwise, if a notification of transmission failure has not been received from the lower layer, increment the SR_COUNTER by 1.

[0109] When the MAC entity has an SR transmission opportunity on the configured valid PUCCH resource for SR; and if the sr-ProhibitTimer is not running at the time of the SR transmission opportunity; and if the PUCCH resource for the SR transmission opportunity does not overlap with a measurement gap; and if the PUCCH resource for the SR transmission opportunity does not overlap with the UL-SCH resource, and if SR_COUNTER < sr-TransMax + 1: Command the physical layer to signal the SR on one of the valid PUCCH resources for SR; start the sr-ProhibitTimer.

[0110] If the SR counter is not incremented, the SR procedure may not terminate. To avoid this, each of the third, fourth, fifth, and tenth embodiments can be used as a solution to terminate the procedure.

[0111] According to the ninth embodiment, for the unlicensed spectrum, due to LBT failure, the SR is not transmitted. In this case, the SR prohibit timer should not be started. The SR should be transmitted as soon as possible at the next available SR transmission opportunity. Then an indication should be notified to the MAC layer. In addition, the SR counter should not be incremented to avoid unnecessary RLF. If a LBT success indication is notified to the MAC layer, the SR prohibit timer is started and the SR counter is incremented by 1. Otherwise the timer is not started and the counter is not incremented. When a LBT success indication is notified to the MAC layer, the handling of the SR procedure in the MAC layer can be modified as follows.

[0112] For the SR configuration corresponding to the non-pending SR: If a notification of transmission success has been received from the lower layer, increment the SR_COUNTER by 1; and start the sr-ProhibitTimer.

[0113] According to the tenth embodiment, if the transmission is blocked in the lower layer, a transmission failure indication is notified to the intermediate layer. Then the transmission failure counter is incremented. When the transmission failure counter reaches the threshold, the failure problem should be indicated to the upper layer.

[0114] For the SR procedure, RACH procedure, and transmission process in the MAC layer, the transmission failure counter can be a unified counter used for these procedures. In addition to the transmission failure counter, a timer is also used. When a transmission failure indication is received and the timer is not running, the timer starts and the transmission counter increments by 1. If a transmission failure indication is received within the timer, the transmission failure counter increments by 1. If the timer expires, the transmission counter is reset. When the transmission failure counter reaches a threshold, the intermediate layer will indicate the transmission failure problem to the upper layer. Taking the RACH procedure as an example, when the RACH procedure is triggered, the following steps can be executed.

[0115] Step 1: The MAC layer selects a preamble and instructs the physical layer to do so.

[0116] Step 2: The physical layer performs LBT before transmission.

[0117] Step 3: If LBT fails, the physical layer notifies the MAC layer of a transmission failure indication.

[0118] Step 4: When a transmission failure is received and the timer is not running, the timer starts and the transmission failure counter increments by 1. When a transmission failure is received within the timer, the transmission failure counter increments by 1. When the timer expires, the transmission failure counter is reset.

[0119] Step 5: If the transmission failure counter reaches the threshold, the MAC layer should indicate the transmission failure problem to the RRC layer.

[0120] Step 6: When the RRC layer receives a transmission failure, it can declare an RLF.

[0121] Besides transmissions indicated by the MAC layer, there are also some message transmissions that do not require MAC layer indication and are transmitted directly at the physical layer, such as HARQ feedback and CSI / SRS transmitted via PUCCH. For these messages, if a transmission failure indication is not sent to the MAC layer when transmission is blocked, the transmission failure counter is only used for statistics on transmission failures of messages indicated by the MAC layer. If a transmission failure indication is sent to the MAC layer, the transmission failure counter will increment once the indication is received. These detailed steps can be described as follows.

[0122] Step 1: HARQ feedback / CSI needs to be transmitted, and only PUCCH resources can be used for transmission in the physical layer.

[0123] Step 2: If LBT fails, the physical layer notifies the MAC layer of a transmission failure indication.

[0124] Step 3: When a transmission failure is received and the timer is not running, the timer starts and the transmission failure counter increments by 1. When a transmission failure is received within the timer, the transmission failure counter increments by 1. When the timer expires, the transmission failure counter is reset.

[0125] Step 4: If the transmission failure counter reaches the threshold, it should indicate a transmission failure problem to the RRC layer.

[0126] Step 5: When the RRC layer receives a transmission failure, it can declare an RLF.

[0127] According to the eleventh embodiment, when transmission is blocked in the lower layer, a transmission failure indication is sent to the intermediate layer. Then, a transmission failure counter is incremented. When the transmission failure counter reaches a threshold, a failure problem should be indicated to the upper layer.

[0128] For the SR procedure, RACH procedure, and transmission process in the MAC layer, the transmission failure counter can be a unified counter used for these procedures. In addition to the transmission failure counter, a timer is also used. When a transmission failure indication is received and the timer is not running, the timer starts and the transmission counter increments by 1. If a transmission failure indication is received within the timer, the transmission failure counter increments by 1. If the timer expires, the transmission counter is reset. When the transmission failure counter reaches a threshold, the intermediate layer will indicate the transmission failure problem to the upper layer.

[0129] Taking the RACH procedure as an example, when the RACH procedure is triggered, the following steps can be executed. Multiple thresholds can be introduced, such as a threshold for the transmission of message 3 (Msg3) in the RACH procedure and a threshold for the transmission of the preamble. When a transmission failure indication for Msg3 is received, the transmission failure counter increments. If the counter reaches the threshold for Msg3 transmission, a transmission failure problem is indicated to the RRC layer. When a transmission failure indication for preamble transmission is received, the transmission failure counter increments. If the counter reaches the threshold for preamble transmission, a transmission failure problem is indicated to the RRC layer.

[0130] According to the twelfth embodiment, when all UL transmissions are blocked in the lower layer, a transmission failure indication is notified to the upper layer. Then, a transmission failure counter is incremented. When the transmission failure counter reaches a threshold, an RLF (Recurrent Link Failure) is triggered. For all uplink transmissions, a common counter and timer are recommended. The statistical methods for failure indications in the third, fourth, fifth, and / or tenth embodiments can also be used in this embodiment.

[0131] While various embodiments of this disclosure have been described above, it should be understood that they are presented merely as examples and not as limitations. Similarly, various figures may depict exemplary architectures or configurations, provided to enable those skilled in the art to understand the exemplary features and functionality of this disclosure. However, such a person will understand that this disclosure is not limited to the exemplary architectures or configurations shown, but can be implemented using various alternative architectures and configurations. Additionally, as will be understood by those skilled in the art, one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of this disclosure should not be limited by any of the exemplary embodiments described above.

[0132] It should also be understood that any reference to elements in this document using designations such as "first," "second," etc., generally does not restrict the number or order of these elements. Rather, these designations may be used herein as a convenient means of distinguishing two or more elements or instances of elements. Therefore, a reference to the first element and the second element does not imply that only two elements can be used, or that the first element must somehow precede the second element.

[0133] Additionally, those skilled in the art will understand that information and signals can be represented using any of a variety of different techniques and processes. For example, data, instructions, commands, information, signals, bits, and symbols (e.g., they may be referenced in the description above) can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0134] Those skilled in the art will further understand that any of the various illustrative logic blocks, modules, processors, devices, circuits, methods, and functions described in connection with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of both), firmware, various forms of program or design code incorporating instructions (which may be referred to herein as "software" or "software module" for convenience), or any combination of these technologies.

[0135] To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been described above in general terms of their functionality. Whether this functionality is implemented as hardware, firmware, software, or a combination of these technologies depends on the specific application and design constraints imposed on the system as a whole. Skilled artisans can implement the described functionality in various ways for each specific application, but such implementation decisions do not depart from the scope of this disclosure. According to various embodiments, processors, devices, components, circuits, structures, machines, modules, etc., can be configured to perform one or more of the functions described herein. The terms “configured to” or “configured for” as used herein with respect to a particular operation or function refer to processors, devices, components, circuits, structures, machines, modules, etc., that are physically constructed, programmed, and / or arranged to perform the specified operation or function.

[0136] Furthermore, those skilled in the art will understand that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented within or executed by an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices or any combination thereof. Logic blocks, modules, and circuits may further include antennas and / or transceivers for communication with various components within a network or device. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors with a digital signal processor core, or any other suitable configuration to perform the functions described herein.

[0137] If implemented as software, functionality can be stored as one or more instructions or code on a computer-readable medium. Therefore, the steps of the methods or algorithms disclosed herein can be implemented as software stored on a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, including any medium that can be enabled to transfer a computer program or code from one place to another. A storage medium can be any available medium that is accessible to a computer. By way of example and not limitation, such a computer-readable medium can include RAM, ROM, EEPROM, CD-ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that is accessible to a computer.

[0138] In this document, as used herein, the term "module" means software, firmware, hardware, and any combination of such elements for performing the associated functions described herein. Additionally, for the purposes of discussion, various modules are described as discrete modules; however, as will be apparent to those skilled in the art, according to embodiments of this disclosure, two or more modules may be combined to form a single module performing associated functions.

[0139] Additionally, in embodiments of this disclosure, memory or other storage devices and communication components may be employed. It should be understood that, for clarity, embodiments of this disclosure have been described above with reference to different functional units and processors. However, it will be apparent that any suitable functional distribution among different functional units, processing logic elements, or domains may be used without departing from this disclosure. For example, functions shown to be performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Therefore, references to specific functional units are merely references to suitable means for providing the described functionality and do not indicate a strict logical or physical structure or organization.

[0140] Various modifications to the embodiments described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the embodiments shown herein, but is accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the foregoing claims.

Claims

1. A method performed by a wireless communication device, the method comprising: The instruction is obtained from the second layer module of the wireless communication device by the first layer module of the wireless communication device, wherein The first-layer module is configured to execute the process at the first layer. The second-layer module is configured to execute processes at a second layer different from the first layer, and The indication indicates whether there is a transmission failure of the wireless communication device at the second layer, wherein a transmission indicated as a failure by the second layer includes both transmissions not indicated by the first layer and transmissions indicated by the first layer. The first layer is equipped with multiple counters, each corresponding to a different type of message transmission. The method further includes: In response to the determination of a failure to transmit a message at the second layer, the counter associated with the message is incremented by 1; and After the counter reaches a predetermined threshold associated with the message, an indication is generated and sent to the third-layer module to indicate a transmission failure associated with the message at the first layer and / or the second layer.

2. The method according to claim 1, wherein the first layer is higher than the second layer.

3. The method according to claim 2, wherein: The first layer is the Media Access Control (MAC) layer; and The second layer is the physical (PHY) layer.

4. The method of claim 1, wherein the transmission failure is caused by at least one of the following: Listen-before-speak (LBT) failed in the unlicensed spectrum; Power back-off; and Conflict with Ultra Reliable Low Latency Communication (URLLC) service.

5. The method according to claim 1, further comprising: The first-layer module commands the second-layer module to transmit a message in the second layer, wherein the transmission failure is a failure to transmit the message in the second layer.

6. The method of claim 5, wherein the message includes information about at least one of: Preamble; Protocol Data Unit (PDU); and Scheduling Request (SR).

7. The method of claim 1, wherein the transmission failure is a failure to transmit a message generated by the second-layer module at the second layer.

8. The method according to claim 1, further comprising: Based on the indication, it is determined that a transmission failure of the wireless communication device exists at the second layer; as well as In response to the determination, the counter at the first layer is incremented by 1.

9. The method according to claim 8, further comprising: In response to the determination, the timer at the first layer is restarted; as well as In response to the timer expiring, the counter at the first layer is reset.

10. The method of claim 8, further comprising: In response to the determination, a timer that is not running in the first layer is started; as well as In response to the timer expiring, the counter at the first layer is reset.

11. The method of claim 8, further comprising: Determine that the counter has reached a predetermined threshold; as well as The third-layer module is instructed to handle the transmission failure issue of the second layer, and the third-layer module is configured to perform the process at a third layer that is different from the first and second layers.

12. The method according to claim 11, wherein: The first layer is the Media Access Control (MAC) layer; The second layer is the physical (PHY) layer; The third layer is the Radio Resource Control (RRC) layer; as well as The third-layer module is also configured to declare a radio link failure (RLF) based on the transmission failure issue indicated by the first layer.

13. The method according to claim 1, further comprising: Based on the indication, it is determined that no transmission failure occurred at the second layer within the predetermined time related to message transmission; as well as In response to the determination, the counter at the first layer is reset, wherein the counter is used to count transmission failures at the second layer.

14. The method according to claim 1, further comprising: Based on the indication, it is determined that a message transmission failure occurred at the second layer; In response to the determination, the counter associated with the message at the first layer is incremented by 1; Determine that the counter has reached a predetermined threshold associated with the message; as well as Indicate a transmission failure issue associated with the message to a third-layer module, which is configured to perform the process at a third layer, distinct from the first and second layers.

15. The method according to claim 1, further comprising: Based on the indication, it is determined that a transmission scheduling request (SR) failure occurred at the second layer; In response to the determination, stop the timer running at the first layer and associated with the SR transmission; and The scheduling request (SR) is transmitted at the second layer at the next available SR transmission opportunity, which is pre-configured and independent of the timer.

16. The method according to claim 1, further comprising: Based on the indication, it is determined that a transmission scheduling request (SR) was successfully established at the second layer; In response to the determination, the counter associated with the SR at the first layer is incremented by 1; In response to the determination, the timer associated with the SR transmission at the first layer is restarted; and In response to the expiration of the timer, the scheduling request (SR) is retransmitted at the second layer.

17. A method performed by a wireless communication device, the method comprising: The wireless transmission of messages is performed at the first layer by the first layer module of the wireless communication device; The first-layer module sends an instruction to the second-layer module of the wireless communication device, wherein: The first-layer module is configured to execute the process in the first layer. The second-layer module is configured to execute processes at a second layer different from the first layer, and The indication indicates whether there was a transmission failure at the first layer, wherein a failed transmission by the first layer includes both transmissions not indicated by the second layer and transmissions indicated by the second layer. The first layer is equipped with multiple counters, each corresponding to a different type of message transmission. The method further includes: In response to the determination of a failure to transmit a message at the second layer, the counter associated with the message is incremented by 1; and After the counter reaches a predetermined threshold associated with the message, an indication is generated and sent to the third-layer module to indicate a transmission failure associated with the message at the first layer and / or the second layer.

18. The method of claim 17, wherein the second layer is higher than the first layer.

19. The method of claim 18, wherein: The first layer is the physical (PHY) layer; and The second layer is the Media Access Control (MAC) layer.

20. The method of claim 17, wherein the transmission failure is caused by at least one of the following: Listen-before-speak (LBT) failed in the unlicensed spectrum; Power back-off; and Conflict with Ultra Reliable Low Latency Communication (URLLC) service.

21. The method of claim 17, further comprising: Instructions for transmitting the message in the first layer are obtained from the second layer module.

22. The method of claim 21, wherein the message includes information about at least one of: Preamble; Protocol Data Unit (PDU); and Scheduling Request (SR).

23. The method of claim 17, further comprising: The first layer module generates a message for transmission in the first layer.

24. A method performed by a wireless communication device, the method comprising: The instruction is obtained from the second layer module of the wireless communication device by the first layer module of the wireless communication device, wherein The first-layer module is configured to execute the process at the first layer. The second-layer module is configured to execute processes at a second layer different from the first layer, and The indication indicates a transmission failure issue at a third layer, distinct from those at the first and second layers. The indication of a failed transmission by the third layer includes both transmissions not indicated by the second layer and transmissions indicated by the second layer. The first layer is equipped with multiple counters, each corresponding to a different type of message transmission. The method further includes: In response to the determination of a failure to transmit a message at the second layer, the counter associated with the message is incremented by 1; and After the counter reaches a predetermined threshold associated with the message, an indication is generated and sent to the third-layer module to indicate a transmission failure associated with the message at the first layer and / or the second layer.

25. The method of claim 24, wherein: The first layer is the Radio Resource Control (RRC) layer; and The second layer is the Media Access Control (MAC) layer; The third layer is the physical (PHY) layer; as well as The first layer module is configured to declare a wireless link failure (RLF) based on an indication of the transmission failure problem.

26. A wireless communication device configured to perform the method according to any one of claims 1 to 25.

27. A non-transitory computer-readable medium having stored thereon computer-executable instructions for performing the method of any one of claims 1 to 25.

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