Communication method and apparatus

Abstract

The application provides a communication method and device, which can be applied to sidelink communication, vehicle-to-everything (V2X) or intelligent driving and the like. The method comprises: determining a starting time point of a resource selection window according to a first time point of triggering resource selection, and selecting a transmission resource in the resource selection window. A time interval between the starting time point of the resource selection window and the first time point is not less than a time length required for performing a first type of listen before talk (LBT) by a terminal device. Through the method, resources in the resource selection window are as much as possible located after the end of LBT, so that the probability of LBT success before communication on the reserved resources can be improved, and in turn the resource utilization can be improved.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0002] Enabling sidelink (SL) communication on unlicensed spectrum is an important direction of evolution in communication system development. Terminal devices also need to perform listen-before-talk (LBT) when communicating on unlicensed spectrum. That is, before accessing the channel and starting to transmit data, the terminal device needs to listen to whether the channel is idle. If the channel has been idle for a certain period, it can occupy the channel; if the channel is not idle, it needs to wait until the channel becomes idle again before it can occupy the channel.

[0003] Currently, SL communication supports resource reservation, meaning that terminal devices can reserve resources for a future period within a resource selection window and indicate this reservation information in their transmitted control information (e.g., sidelink control information (SCI)). Other users receiving this control information can exclude the reserved resources indicated by the control information, thus avoiding resource collisions. However, in unlicensed spectrum sidelink communication, terminal devices need to perform LBT (Local Backoff Counter) before communicating on reserved resources. This means the terminal device needs to determine the required waiting time based on a randomly generated initial value of the backoff counter. Since each terminal user generates a different initial value, the success of LBT before reserving resources becomes random, potentially preventing the terminal device from communicating on its reserved resources. Summary of the Invention

[0004] This application provides a communication method and apparatus that can improve resource utilization.

[0005] Firstly, this application provides a communication method. The subject executing this method can be a terminal device, a combination device or component with terminal device functions, or a chip or circuit system (e.g., a processor, baseband chip, or chip system) applied in the terminal device. The method includes: determining the start time point of a resource selection window based on a first time point that triggers resource selection, and selecting transmission resources within the resource selection window. The time interval between the start time point of the resource selection window and the first time point is not less than the duration required for the terminal device to perform a first type of Listen-Before-Speak (LBT).

[0006] In this embodiment, the start time of the resource selection window is determined based on the duration required for the first type of LBT (Low Bit By-BT). This ensures that as many resources as possible within the selection window are located after the LBT ends, thereby increasing the probability of a successful LBT before communication occurs on reserved resources, and thus improving resource utilization. Furthermore, with this scheme, the receiving terminal device does not need to detect information on resources before the sending terminal device's LBT succeeds, thereby reducing the power consumption of the receiving terminal device.

[0007] In one possible design, the number of time slots T1 corresponding to the time interval between the start time point of the resource selection window and the first time point can satisfy:

[0008] exist In this case, And / or,

[0009] exist In the case of T1 = T;

[0010] in, The first processing duration is predefined, and T is the number of time slots corresponding to the first duration.

[0011] In one possible design, the first duration is determined based on the initial value of the random backoff counter corresponding to the first type of LBT. In the above design, the case of interruption during the random backoff counter counting period can be ignored. Estimating the first duration based on the initial value of the random backoff timer can reduce computational complexity and save computational resources.

[0012] In one possible design, the first duration can be determined based on the initial value of the random backoff counter corresponding to the first type of LBT and the first interval in the first type of LBT. In the above design, by considering the continuous idle duration of the channel to be monitored in the LBT (i.e., the first interval), the probability of successful LBT before communication on the reserved resources can be further increased, thereby improving resource utilization.

[0013] In one possible design, the first interval can be the duration of channel idle time in the first type of LBT, that is, the duration of continuous channel idle time that the terminal device needs to wait for when performing the first type of LBT.

[0014] In one possible design, the first interval can be the DIFS duration in the WIFI protocol, or the first interval can be the defer duration in the 3GPP protocol.

[0015] In one possible design, the number T of time slots corresponding to the first duration satisfies:

[0016]

[0017] Where counter is the initial value of the random backoff counter, and μ corresponds to the subcarrier spacing.

[0018] In one possible design, when selecting transmission resources within the resource selection window, candidate resources located after the end time of the LBT (Low Bit Bypass) can be selected as transmission resources in chronological order. This increases the probability of successful LBT before communication occurs on reserved resources and also increases the likelihood of communication occurring on the selected resources.

[0019] In one possible design, the first duration can be determined based on the initial value of the random backoff counter corresponding to the first type of LBT and the second duration, where the second duration is the number of time slots occupied by the N reserved resources. Alternatively, the second duration can be determined based on the number of time slots occupied by the N reserved resources and the N first intervals, where the first interval is the channel idle duration after the corresponding reserved resource, and the first interval is temporally continuous with the corresponding reserved resource. The N reserved resources are the resources reserved within the first duration, where N is a positive integer.

[0020] Because the random backoff counter is interrupted if another terminal device sends a signal in the same time slot during the random backoff process, the time required for LBT success increases. In the above scheme, by considering the duration of the random backoff counter interruption when determining the start time of the resource selection window, the probability of successful LBT before communication on the reserved resources can be further increased, thus increasing the likelihood that the terminal device will send information on the resource selected within the resource selection window.

[0021] In one possible design, the number of time slots T corresponding to the first duration can satisfy:

[0022]

[0023] Where counter is the initial value of the random backoff counter, μ corresponds to the subcarrier spacing, and reservation i Let be the number of time slots occupied by the i-th reserved resource out of N reserved resources. In the above design, the duration of the random backoff counter interruption can be determined based on the number of time slots occupied by the reserved resources. This approach has low complexity, saves computational resources, and reduces power consumption.

[0024] In one possible design, the number of time slots T corresponding to the first duration can satisfy:

[0025]

[0026] Where counter is the initial value of the random backoff counter, μ corresponds to the subcarrier spacing, and reservation iLet t be the number of time slots occupied by the i-th reserved resource out of N reserved resources, and t be the first interval. The above design takes into account the time required for LBT to restart after each interruption of the random backoff counter (i.e., the first interval), making the interruption time of the random backoff counter more accurate, thereby further improving the probability of successful LBT before communication on the reserved resources.

[0027] In one possible design, the N reserved resources are indicated by M side-by-side control messages within a resource listening window, where M is a positive integer. Each of the M side-by-side control messages corresponds to a Reference Signal Received Power (RSRP) greater than a first threshold, which is the RSRP threshold used for resource selection. Alternatively, each of the M side-by-side control messages corresponds to a Received Signal Strength Indication (RSSI) greater than a second threshold, which is the RSSI threshold used for LBT (Local Bit Bypass). Or, each of the M side-by-side control messages corresponds to an RSRP greater than the first threshold, and also corresponds to an RSSI greater than the second threshold. This design allows for the consideration of reserved resources that may cause significant interference to terminal equipment, thereby improving resource utilization.

[0028] Secondly, embodiments of this application provide a communication device that can implement the method described in the first aspect or any possible design thereof. The device includes corresponding units or components for performing the above-described methods. The units included in the device can be implemented in software and / or hardware. The device can be, for example, a terminal device, or a component, baseband chip, chip system, or processor that supports the implementation of the above-described methods in a terminal device.

[0029] For example, the communication device may include a processing unit (or processing module), and may also include modular components such as a transceiver unit (or communication module, transceiver module), which can perform the methods described in the first aspect above or any possible design therein. When the communication device is a terminal device, the transceiver unit may be a transmitter and a receiver, or a transceiver obtained by integrating a transmitter and a receiver. The transceiver unit may include an antenna and radio frequency circuits, etc., and the processing unit may be a processor, such as a baseband chip. When the communication device is a component with the functions of the aforementioned terminal device, the transceiver unit may be a radio frequency unit, and the processing unit may be a processor. When the communication device is a chip system, the transceiver unit may be the input / output interface of the chip system, and the processing unit may be the processor of the chip system, such as a central processing unit (CPU).

[0030] The transceiver unit can be used to perform receiving and / or transmitting actions in the first aspect or any possible design thereof. The processing unit can be used to perform actions other than receiving and transmitting in the first aspect or any possible design thereof, such as determining the start time point of the resource selection window, selecting transmission resources within the resource selection window, etc.

[0031] Thirdly, a communication device is provided, including one or more processors coupled to a memory for executing programs or instructions in the memory to cause the device to perform the methods described in the first aspect or any possible design within that aspect. Optionally, the device further includes one or more memories. Optionally, the device also includes a communication interface, to which the processor is coupled.

[0032] Fourthly, a computer-readable storage medium is provided for storing computer instructions that, when executed on a computer, cause the computer to perform the methods described in the first aspect or any possible design thereof.

[0033] Fifthly, a computer program product containing instructions is provided, the computer program product being used to store computer instructions that, when executed on a computer, cause the computer to perform the methods described in the first aspect or any possible design thereof.

[0034] In a sixth aspect, a processing apparatus is provided, coupled to a memory, which invokes a program in the memory to execute the methods described in the first aspect or any possible design thereof. The processing apparatus may, for example, include a chip system.

[0035] The chip system mentioned above can be a system on chip (SOC) or a baseband chip, etc. The baseband chip can include processors, channel encoders, digital signal processors, modems and interface modules, etc. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a V2X communication embodiment of this application;

[0037] Figure 2 These are schematic diagrams of four LBTs according to embodiments of this application;

[0038] Figure 3 This is a schematic diagram of a random retreat according to an embodiment of this application;

[0039] Figure 4 This is a schematic diagram of a network architecture according to an embodiment of this application;

[0040] Figure 5This is a schematic diagram of another network architecture according to an embodiment of this application;

[0041] Figure 6 This is a schematic diagram of another network architecture according to an embodiment of this application;

[0042] Figure 7 This is a schematic diagram of the structure of a communication device according to an embodiment of this application;

[0043] Figure 8 This is a schematic diagram of the structure of a terminal device according to an embodiment of this application;

[0044] Figure 9 This is a flowchart illustrating a communication method according to an embodiment of this application;

[0045] Figure 10 This is a schematic diagram of a resource selection window according to an embodiment of this application;

[0046] Figure 11 This is a schematic diagram of another resource selection window according to an embodiment of this application;

[0047] Figure 12 This is a schematic diagram illustrating one resource selection method according to an embodiment of this application;

[0048] Figure 13 This is a schematic diagram illustrating another resource selection method according to an embodiment of this application;

[0049] Figure 14 This is a schematic diagram of a resource selection window according to an embodiment of this application;

[0050] Figure 15 This is a schematic diagram illustrating one resource selection method according to an embodiment of this application. Detailed Implementation

[0051] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0052] The following explanations of some terms used in the embodiments of this application are provided to facilitate understanding by those skilled in the art.

[0053] 1) Terminal equipment, including equipment that provides voice and / or data connectivity to users, specifically including equipment that provides voice to users, or equipment that provides data connectivity to users, or equipment that provides both voice and data connectivity to users. For example, it may include a handheld device with wireless connectivity or a processing device connected to a wireless modem. This terminal equipment can communicate with the core network via a radio access network (RAN), exchanging voice or data with the RAN, or interacting with the RAN for both voice and data. The terminal equipment may include user equipment (UE), wireless terminal equipment, mobile terminal equipment, device-to-device (D2D) terminal equipment, vehicle-to-everything (V2X) terminal equipment, machine-to-machine / machine-type communications (M2M / MTC) terminal equipment, internet of things (IoT) terminal equipment, subscriber unit, subscriber station, mobile station, remote station, access point (AP), remote terminal, access terminal, user terminal, user agent, or user device, etc. For example, it may include mobile phones (or "cellular" phones), computers with mobile terminal devices, portable, pocket-sized, handheld, or computer-embedded mobile devices, etc. Examples include Personal Communication Service (PCS) phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, and Personal Digital Assistants (PDAs). It also includes limited devices, such as those with low power consumption, limited storage capacity, or limited computing power. Examples include information sensing devices such as barcode scanners, radio frequency identification (RFID), sensors, Global Positioning System (GPS) devices, and laser scanners.

[0054] In V2X technology, the terminal device can be a roadside unit (RSU). An RSU can be a fixed infrastructure entity that supports V2X applications and can exchange messages with other entities that support V2X applications. For example, the roadside unit can exchange messages with other entities that support V2X applications through the PC5 port.

[0055] Terminal devices in V2X technology can also be the entire vehicle, communication modules within the vehicle (such as communication chips, chip systems, etc.), telematics boxes (TBOX), and so on.

[0056] By way of example and not limitation, in this embodiment, the terminal device can also be a wearable device. Wearable devices, also known as wearable smart devices or smart wearable devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not merely hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are feature-rich, large in size, and can achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those that focus on a specific type of application function and require the use of other devices such as smartphones, such as various smart bracelets, smart helmets, and smart jewelry for vital sign monitoring.

[0057] The various terminal devices described above, if located in a vehicle (e.g., placed inside or installed inside a vehicle), can be considered as vehicle-mounted terminal devices, also known as on-board units (OBUs).

[0058] In this embodiment, the terminal device may further include a relay. Alternatively, it can be understood that anything capable of data communication with a base station can be considered a terminal device.

[0059] In this application embodiment, the device for implementing the functions of the terminal device can be the terminal device itself, or it can be a device applied in the terminal device that enables the terminal device to implement the functions, such as a component or assembly with communication functions, or a chip system. This device can be installed in the terminal device. In this application embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. In the technical solutions provided in this application embodiment, the terminal device is used as an example to describe the technical solutions provided in this application embodiment.

[0060] 2) Network devices, including access network (AN) devices such as base stations (e.g., access points), can refer to devices in the access network that communicate with wireless terminal devices via one or more cells over the air interface, or, for example, a network device in a V2X technology that is a base station-type RSU. The base station can be used to convert received air frames to and from Internet Protocol (IP) packets, acting as a router between the terminal device and the rest of the access network, which may include an IP network. The base station-type RSU can be a fixed infrastructure entity supporting V2X applications and can exchange messages with other entities supporting V2X applications; for example, the base station-type roadside unit can exchange messages with other entities supporting V2X applications via a Uu interface. The network device can also coordinate the management of air interface attributes. For example, network equipment may include evolved base stations (NodeBs, eNBs, or e-NodeBs) in LTE systems or Long Term Evolution-Advanced (LTE-A) systems, or next-generation node Bs (gNBs) in 5th generation (5G) NR systems (also referred to as NR systems), or centralized units (CUs) and / or distributed units (DUs) in cloud radio access networks (Cloud RAN) systems. This application embodiment is not limited to these categories. For example, network equipment may be a CU, a DU, or a combination of CUs and DUs in a Cloud RAN system.

[0061] Network devices may also include core network devices, such as those including access and mobility management functions (AMF). Since this application primarily relates to access networks, unless otherwise specified, the network devices mentioned below refer to access network devices.

[0062] In this application embodiment, the device for implementing the function of the network device can be the network device itself, or it can be a device capable of supporting the network device in implementing that function, such as a chip system, which can be installed in the network device. In the technical solutions provided in this application embodiment, the example of a network device being used to implement the function of the network device is used to describe the technical solutions provided in this application embodiment.

[0063] 3) V2X, or vehicle-to-everything (V2X), is the interconnection and interoperability between vehicles and the outside world. It is the foundation and key technology for future intelligent vehicles, autonomous driving, and intelligent transportation systems. V2X will optimize the specific application requirements of V2X based on existing device-to-device (D2D) technology, and further reduce the access latency of V2X devices and resolve resource conflict issues.

[0064] V2X specifically includes several application requirements such as direct communication between vehicles (V2V), between vehicles and roadside infrastructure (V2I), between vehicles and pedestrians (V2P), and communication and interaction between vehicles and networks (V2N). Figure 1 As shown. V2V refers to communication between vehicles; V2P refers to communication between vehicles and people (including pedestrians, cyclists, drivers, or passengers); V2I refers to communication between vehicles and network devices, such as RSUs. There is also a type called V2N that can be included in V2I, which refers to communication between vehicles and base stations / networks.

[0065] 4) The resource selection window is the time slot [n+T1, n+T2] corresponding to the resource selection triggered by the terminal device. Here, n is the time point when the terminal device triggers resource selection, i.e., the time point when the resource selection process is triggered. This resource selection process can be the process by which the terminal device determines the PSSCH resources to report to the higher layers, or the process by which the terminal device determines a subset of resources from the resources selected by the higher layers for PSSCH / PSCCH transmission. T1 is determined by the terminal device and represents the processing delay for the terminal device to process the listening results and determine candidate resources after the resource selection trigger time point. For example, T1 can satisfy... For the maximum value of T1 as defined by the standard, in one example, It can be defined by Table 1, where μ can be configured by the sub-carrier spacing (SCS) corresponding to the bandwidth part (BWP) of SL. For example, μ can be defined by Table 2. T2 is determined by the terminal device and is a value less than the packet delay budget (PDB) requirement of the data packet to be sent.

[0066] Table 1

[0067]

[0068] Table 2

[0069] μ Subcarrier spacing (kHz) 0 15 1 30 2 60 3 120 4 240

[0070] 5) The resource listening window is a set of time slots, which serves as the basis for the terminal device's sensing. When the terminal device triggers resource selection at time point n, it determines whether the candidate resources in the resource selection window have been reserved, i.e., whether they are available, based on the correctly received SCI bearer information within the corresponding resource listening window. The time range of the resource listening window is [n-t0, nt]. proc，0 Here, t0 is the boundary value of the resource listening window, and its specific value is configured or pre-configured by the network side. For example, the duration of t0 can be 1100ms or 100ms (or other values). Taking a 15kHz subcarrier spacing as an example, t0 = 1100 slots or 100 slots; taking a 60kHz subcarrier spacing as an example, t0 = 4400 slots or 400 slots; t proc，0 The time for the terminal device to process the listening results, t is defined by the standard for different subcarrier intervals. proc，0 The maximum value, depending on the capabilities of the terminal device, can be determined by the terminal device itself while satisfying the maximum value constraint. proc，0 Take values, and t proc，0 ≥0.

[0071] 6) LBT: In wireless communication systems, frequency bands can be divided into licensed and unlicensed bands based on their usage. In unlicensed bands, transmitting nodes need to perform LBT during communication. That is, before accessing the channel and starting to transmit data, the transmitting node needs to listen for idle time. If the channel is not idle, it cannot transmit signals on that channel; if the channel is idle and the idle time meets the LBT requirements, it can occupy the channel. The following describes four channel access types, differing only in the required waiting time. Figure 2 As shown.

[0072] In the first channel access method (corresponding to Cat 1 LBT in the WIFI protocol, or Type 2B LBT in the 3GPP protocol), the transmitting node transmits after a short handover interval. For example, the transmitting node waits for the channel to become idle for a short inter-frame space (SIFS) before accessing the channel. In one example, the SIFS includes a 9µs time slot. If the terminal device detects that the channel has been idle for at least 5 microseconds during that 9µs time slot, the channel can be considered idle during that SIFS period. The delay defined by the SIFS can include the propagation delay of the radio waves carrying the signal in space, the signal processing delay of the receiving user, and the handover delay of the receiving user.

[0073] In the second channel access method (corresponding to Cat 2 LBT in the Wi-Fi protocol, or Type 2A LBT in the 3GPP protocol), the transmitting node performs an LBT without random backoff. For example, the transmitting node waits for the duration of the continuous idle point coordination function inter-frame space (PIFS) before accessing the channel. Here, PIFS can be equal to (SIFS + slotTime), where slotTime is the length of a time slot, which can last for 9 microseconds. In this second channel access method, the duration for which the channel is detected as idle before the transmitting node accesses the channel is deterministic.

[0074] In the third channel access method (corresponding to Cat 3LBT in the WIFI protocol), the transmitting node waits for the channel to be continuously idle for the duration of the distributed coordination function interframe space (DIFS) before accessing the channel. DIFS can be equal to (SIFS + 2 * slotTime). Successful access of the transmitting node to the channel can be called successful DIFS.

[0075] In the fourth channel access method (corresponding to Cat4LBT in the WIFI protocol, or Type 1 LBT in the 3GPP protocol), after the transmitting node determines the channel's continuous idle DIFS duration, it waits for the channel to become idle for the specified random backoff duration before accessing the channel. The random backoff mechanism requires the transmitting node to select an initial value for a random backoff count. This initial value represents the number of slotTimes the transmitting node needs to wait for after a successful DIFS. This slotTime can be the smallest time granularity for channel resource awareness on unlicensed frequency bands. When the transmitting node determines that the channel has been idle for a continuous DIFS duration, it starts a random backoff counter. The initial value of this random backoff counter is the initial value selected by the transmitting node. If the transmitting node determines that the channel has been idle for a continuous slotTime duration, the random backoff counter is decremented by one; otherwise, if the channel is considered busy, the random backoff counter is interrupted, and the current value of the random backoff counter is recorded. After the transmitting node resumes listening following an interruption in the random backoff counter, it continues listening until DIFS succeeds. The random backoff counter then decrements until it reaches 0, indicating successful access. The transmitting node then begins transmitting signals on the channel (also known as accessing the channel, using the channel, or occupying the channel). Figure 3As shown, assume there are four transmitting nodes in the spatial range: STA1, STA2, STA3, and STA4. All four nodes can receive signals from each other, and the energy of the received signals is above a threshold. This means that when one node transmits a signal, the other nodes detect a busy channel. Assuming STA1 initially starts transmitting on an unlicensed frequency band, the other nodes perform LBT (Local Backoff Counter). Taking STA2's randomly generated backoff counter as the largest, followed by STA4, and then STA3's as the smallest, after STA1 finishes transmitting, the other nodes detect the channel as idle. After the duration defined by DIFS (Discretionary Backoff Detection), the backoff counters of STA2, STA3, and STA4 all begin to decrement. However, STA3's backoff counter, being the smallest, decrements to 0 first and transmits data. After STA3 starts transmitting, STA2 and STA4 detect the channel as busy again, and their backoff counters stop decrementing. STA2 and STA4 continue energy detection until the channel is idle (i.e., STA3 has finished transmitting its signal), after which the random backoff counter value restarts its decrement. Since STA4's random backoff counter value is smaller than STA2's, STA4 decrements to 0 and begins transmitting data. After STA4 begins transmitting, STA2 detects that the channel is busy again, and the random backoff counter stops decrementing again. STA2 continues energy detection until the channel is idle (i.e., STA4 has finished transmitting its signal), after which the random backoff counter value restarts its decrement until it reaches 0, at which point it begins transmitting.

[0076] 7) The initial value of the random backoff count represents the number of slotTimes the transmitting node needs to wait for after a successful DIFS. The initial value of the random backoff count is a positive integer randomly selected by the transmitting node within the contention window [0, CW], and is uniformly distributed within the window, i.e., 0 ≤ random backoffcount ≤ CW. Here, CW represents the contention window length, and its initial value is CW. min When a user sends invalid data, the value of CW doubles, i.e., CW = CW * 2, until CW = CW. max Invalid data transmission indicates that the sending node did not receive an ACK response from the receiving node. For example, CW... min and CW max The possible values ​​for CW are shown in Table 3. min and CW max The value of CW can be related to the channel access priority p, with different priorities corresponding to different CW values. min，p and CW max，pThe maximum allowed access duration (i.e., the maximum continuous usable duration of the channel) T ulm cot，p different.

[0077] Table 3

[0078]

[0079] In the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0080] Furthermore, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the size, content, order, timing, priority, or importance of multiple objects. For example, the first threshold value and the second threshold value are only used to distinguish different threshold values, and do not indicate that the two threshold values ​​have different priorities or importance.

[0081] The preceding text introduced some terms and concepts involved in the embodiments of this application. The following text introduces the technical features involved in the embodiments of this application.

[0082] Currently, sidelink communication supports resource reservation, meaning terminal devices can reserve resources for a future period within a resource selection window. Since transmitting nodes need to perform LBT (Local Backoff Counter) during communication in unlicensed spectrum, terminal devices also need to perform LBT before communicating on reserved resources when conducting sidelink communication in unlicensed spectrum. This means the terminal device needs to determine the waiting time based on a randomly generated initial value of the backoff counter. Since each terminal user generates a different initial value, the success of LBT on reserved resources becomes random. This is especially true in the fourth channel access method (i.e., Cat 4 LBT in the Wi-Fi protocol or Type 1 LBT in the 3GPP protocol), where the random backoff counter may be interrupted during LBT, further complicating the success of LBT on reserved resources and potentially preventing the terminal device from communicating on those resources.

[0083] Based on this, embodiments of this application provide a communication method and apparatus. By determining the start time of the resource selection window according to the duration required for the terminal device to perform LBT (Least Bit Bypass), the resources within the resource selection window are positioned as far as possible after the LBT ends. This increases the probability of successful LBT before communication on reserved resources, improves the likelihood of the terminal device sending information on the resources selected within the resource selection window, and increases the likelihood of the other terminal device receiving information on those resources. Consequently, it reduces the power consumption of the other terminal device when receiving information. The method and apparatus are based on the same inventive concept. Since the principles by which the method and apparatus solve the problem are similar, their implementations can be mutually referred to, and repeated details will not be elaborated further.

[0084] The technical solutions provided in this application can be applied to protocol frameworks such as LTE, NR, or 6G. Specifically, they can be applied to D2D scenarios, such as V2X, LTE-V, and V2V in vehicle-to-everything (V2X) scenarios, which may include, but are not limited to, intelligent driving and intelligent connected vehicles.

[0085] The embodiments of this application can be applied to unlicensed spectrum. For example, the embodiments of this application can be applied to frame-based equipment (FBE) scenarios in unlicensed spectrum.

[0086] The technical solutions provided in this application can be applied to user-selectable resource modes in communication scenarios with or without network coverage. The network architecture used in this application is described below. Please refer to... Figures 4-6 This is a network architecture used in the embodiments of this application.

[0087] Figures 4-6 This includes network equipment and two terminal devices, namely Terminal Device 1 and Terminal Device 2. Both terminal devices can be within the coverage area of ​​the network equipment, such as... Figure 4 As shown; or, alternatively, only terminal device 1 may be within the coverage area of ​​the network device, while terminal device 2 may not be within the coverage area of ​​the network device, such as... Figure 5 As shown; or both terminal devices are not within the coverage area of ​​the network device, such as Figure 6 As shown. These two terminal devices can communicate via a sidelink. Of course... Figures 4-6 The number of terminal devices mentioned is just an example. In actual applications, network devices can provide services to multiple terminal devices.

[0088] Figures 4-6Network devices in this context include, for example, access network devices such as base stations. The term "access network device" can refer to different devices in different systems. For instance, in the 4th generation (4G) mobile communication system, it might correspond to an eNB; in the 5G system, it might correspond to 5G access network devices such as a gNB; or it could be an access network device in subsequent evolved communication systems.

[0089] in, Figures 4-6 The terminal device in this embodiment is an in-vehicle terminal device or a vehicle, but the terminal device in this application is not limited to this.

[0090] The possible structure of the terminal device will be described below with reference to the accompanying drawings.

[0091] For example, Figure 7 A schematic diagram of one possible structure of the device is shown. Figure 7 The device shown can be a terminal device, or a chip, communication module, telematics box (TBOX), or other combined device, component (or assembly) with the functions of the terminal device shown in this application, applied within the terminal device. The device may include a processing module 710 and a transceiver module 720. The transceiver module 720 can be a single functional module capable of both transmitting and receiving operations. For example, the transceiver module 720 can be used to perform both transmitting and receiving operations performed by the terminal device. For instance, when performing a transmitting operation, the transceiver module 720 can be considered the transmitting module, and when performing a receiving operation, it can be considered the receiving module. Alternatively, the transceiver module 720 can be two functional modules, collectively referred to as the transmitting module and the receiving module. The transmitting module performs the transmitting operation, for example, it can perform the transmitting operation performed by the terminal device, and the receiving module performs the receiving operation, which can be performed by the terminal device.

[0092] For example, when the device is a terminal device, the transceiver module 720 may include a transceiver and / or a communication interface. The transceiver may include an antenna and radio frequency circuitry, etc. The communication interface may be, for example, a fiber optic interface. The processing module 710 may be a processor, such as a baseband processor, which may include one or more central processing units (CPUs).

[0093] When the device is a component with the terminal equipment functions shown in this application, the transceiver module 720 may be a radio frequency unit, and the processing module 710 may be a processor, such as a baseband processor.

[0094] When the device is a chip system, the transceiver module 720 can be the input / output interface of the chip (e.g., a baseband chip), and the processing module 710 can be the processor of the chip system, which may include one or more central processing units.

[0095] It should be understood that the processing module 710 in the embodiments of this application can be implemented by a processor or processor-related circuit components, and the transceiver module 720 can be implemented by a transceiver or transceiver-related circuit components.

[0096] In one implementation, the processing module 710 can be used to perform operations other than the sending and receiving operations performed by the terminal device in the embodiments of this application, such as processing operations, and / or other processes to support the technology described herein, such as determining the start time of a resource selection window, selecting transmission resources within the resource selection window, and processing messages, information, and / or signaling received by the sending and receiving module 720. The sending and receiving module 720 can be used to perform the receiving and / or sending operations performed by the terminal device in the embodiments of this application, and / or other processes to support the technology described herein. Optionally, the processing module 710 can control the sending and receiving module 720 to perform receiving and / or sending operations.

[0097] Figure 8 A schematic diagram of another possible structure for the terminal device is shown. For example... Figure 8 As shown, the terminal device includes a processor, and may also include a memory, a radio frequency (RF) unit (or RF circuit), an antenna, or input / output devices. The processor is mainly used for processing communication protocols and data, controlling the device, executing software programs, and processing software program data. The memory is mainly used to store software programs and data. The RF unit is mainly used for converting baseband signals to RF signals and processing RF signals. The antenna is mainly used for transmitting and receiving RF signals in the form of electromagnetic waves. Input / output devices, such as touchscreens, displays, and keyboards, are mainly used to receive user input data and output data to the user. It should be noted that some types of terminal devices may not have input / output devices.

[0098] When data needs to be sent, the processor performs baseband processing on the data to be sent and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit then processes the baseband signal and transmits it outward as electromagnetic waves through the antenna. When data is sent to the terminal device, the RF circuit receives the RF signal through the antenna, converts it into a baseband signal, and outputs the baseband signal to the processor. The processor then converts the baseband signal back into data and processes it. For ease of explanation, Figure 8Only one memory and processor are shown in the illustration. In actual terminal device products, there may be one or more processors and one or more memories. Memory may also be referred to as storage medium or storage device, etc. Memory may be set up independently of the processor or integrated with the processor; this application does not limit this.

[0099] In this embodiment, the antenna and radio frequency circuit with transceiver functions can be regarded as the transceiver unit of the terminal device (the transceiver unit can be a single functional unit capable of transmitting and receiving functions; or, the transceiver unit can include two functional units, namely a receiving unit capable of receiving and a transmitting unit capable of transmitting), and the processor with processing functions can be regarded as the processing unit of the terminal device. Figure 8 As shown, the terminal device includes a processing unit 820 and may also include a transceiver unit 810. The transceiver unit can also be called a transceiver, transceiver machine, transceiver device, etc. The processing unit can also be called a processor, processing board, processing module, processing device, etc. Optionally, the device in the transceiver unit 810 used to implement the receiving function can be considered as a receiving unit, and the device in the transceiver unit 810 used to implement the transmitting function can be considered as a transmitting unit; that is, the transceiver unit 810 includes both a receiving unit and a transmitting unit. The transceiver unit may also be called a transceiver, transceiver, or transceiver circuit, etc. The receiving unit may also be called a receiver, receiver, or receiving circuit, etc. The transmitting unit may also be called a transmitter, transmitter, or transmitting circuit, etc.

[0100] It should be understood that the transceiver unit 810 may correspond to the transceiver module 720, or in other words, the transceiver module 720 may be implemented by the transceiver unit 810. The transceiver unit 810 is used to execute the sending and receiving operations of the terminal device in the embodiments shown in this application, and / or to support other processes of the technology described herein. The processing unit 820 may correspond to the processing module 710, or in other words, the processing module 710 may be implemented by the processing unit 820. The processing unit 820 is used to execute other operations on the terminal device in the embodiments shown in this application besides the sending and receiving operations, such as executing the receiving and / or sending operations performed by the terminal device in the embodiments shown in this application, and / or to support other processes of the technology described herein.

[0101] The network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0102] It should be noted that the embodiments of this application only use time slots as the time unit for illustration. In specific embodiments, the time unit can also be replaced with other time units such as frames, subframes, half frames, mini time slots or symbols, etc. There is no limitation on the time unit here.

[0103] See Figure 9 This is a flowchart illustrating a communication method provided in this application. The subject executing this method can be a terminal device, a combination device or component with terminal device functions, or a communication chip (such as a processor, baseband chip, or chip system) applied in a terminal device.

[0104] S901, Determine the start time point of the resource selection window.

[0105] Specifically, the time interval between the start time of the resource selection window and the time point n that triggers resource selection (hereinafter referred to as the first time point) is not less than (i.e., greater than or equal to) a first duration, which is the duration required for the terminal device to execute the first type of LBT. In one example, the first time point n can be the time slot that triggers resource selection. The explanation of the first duration will be detailed below.

[0106] The time point that triggers resource selection can be understood as the time point that triggers the resource selection process. The resource selection process can refer to the process by which the terminal device determines the PSSCH resources to be reported to the higher layer, or it can refer to the process by which the terminal device determines a subset of the resources used by the higher layer to select PSSCH / PSCCH transmission.

[0107] For example, the first type of LBT can be the fourth channel access method mentioned in the terminology introduction above, namely Cat 4 LBT in the WIFI protocol, or Type 1 LBT in the 3GPP protocol.

[0108] In one embodiment, in step S901, the start time point of the resource selection window can be determined by at least one of the following two methods:

[0109] Method 1, in In this case, In this method, the value of T1 is determined by the terminal device itself, and the range of T1 values ​​satisfies...

[0110] Method 2, in In this case, T1 = T. In this method, the value of T1 is T.

[0111] in, It can be a predefined first processing time, which may include the processing delay of the sensing results, the processing time required to report the physical layer sensing results to the media access control (MAC) layer, the processing time required for the MAC layer to complete the final resource selection process, the processing time required for data transmission, or the processing delay such as switch switching delay. The definition can be found in Table 1 above. T is the number of time slots corresponding to the first duration, and T1 is the number of time slots corresponding to the time interval between the start time of the resource selection window and the time point n that triggers resource selection.

[0112] For example, step S901 can be performed by processing module 710.

[0113] S902, select the transfer resource in the resource selection window.

[0114] Step S902 can be executed by the processing module 710.

[0115] Specifically, the method by which the terminal device selects transmission resources within the resource selection window will be explained in detail below in conjunction with the method for determining the start time of the resource selection window.

[0116] In V2X communication, if Vehicle 1 communicates with a vehicle on the opposite side in unlicensed spectrum, and Vehicle 1 fails to successfully perform a Level Bypass (LBT) before its reserved resource, it will be unable to communicate with the opposite vehicle on that reserved resource. Since Vehicle 1 sends an SCI (Service Control Information) to other vehicles after reserving the resource to indicate that it has been reserved, other vehicles will also be unable to use the resource, resulting in wasted resources. Furthermore, because Vehicle 1 cannot communicate with the opposite vehicle on its reserved resource, the opposite vehicle will not receive Vehicle 1's information in a timely manner. This could lead to sudden traffic situations. For example, if Vehicle 1 is traveling on a highway and reserves resource 1 to send its driving information (such as speed and direction) at an intersection, but fails to successfully perform an LBT before resource 1, other vehicles will not receive Vehicle 1's driving information at the intersection on resource 1, resulting in traffic safety hazards.

[0117] In this embodiment, the start time of the resource selection window is determined based on the duration required for the first type of LBT (Low-Time Bypass). This ensures that as many resources within the selection window as possible are located after the LBT ends, thereby increasing the probability of a successful LBT before communication occurs on reserved resources, and thus improving resource utilization. Furthermore, this scheme increases the likelihood of the terminal device sending information on the resources selected within the resource selection window, and the likelihood of the receiving terminal device receiving information. Additionally, in this scheme, the receiving terminal device does not need to detect information on resources before the sending terminal device's LBT succeeds, thereby reducing the power consumption of the receiving terminal device.

[0118] In this embodiment, the first duration may be the estimated duration of LBT (Local Time Bypass) that the terminal device might need, rather than the actual duration required for the terminal device to perform LBT. When determining the first duration, the terminal device may consider the possibility of interruption during the random backoff counter counting period, or it may not consider such interruptions. The possibility of interruption during the random backoff counter counting period can be, but is not limited to, the random backoff counter being interrupted by N reserved resources, where N reserved resources are the resources reserved within the first duration, and N is a positive integer. For example, the N reserved resources can be resources indicated by SCIs detected by the terminal device within the resource listening window. Specifically, the terminal device can detect SCIs within the resource listening window and determine the resources reserved within the first duration based on the detected SCIs. The specific method for determining the reserved resources will be described in detail below when the terminal device determines the first duration considering interruptions during the random backoff counter counting period.

[0119] Below, we will first explain in detail the two methods for determining the first duration.

[0120] In the scheme where the terminal device determines the first duration without considering interruptions during the random backoff counter counting period, the terminal device can default to having no reserved resources during the random backoff counter counting period (i.e., the number of reserved resources is 0). In this method, the terminal device can estimate the first duration based on the initial value of the random backoff timer. That is, the first duration can be determined based on the initial value of the random backoff counter corresponding to the first type of LBT. This random backoff counter can record the random backoff count selected by the terminal device during the first LBT process; it can also be understood that the initial value of the random backoff counter is the initial value of the random backoff count selected by the terminal device during the first LBT process. For a detailed explanation of the meaning of the initial value of the random backoff count, please refer to the relevant description of the initial value of the random backoff count in the terminology introduction 6) above, which will not be repeated here.

[0121] In this scheme, the first duration is determined based on the initial value of the random backoff counter corresponding to the first type of LBT, which can also be understood as being determined based on the initial value of the random backoff counter selected by the terminal device during the first LBT process.

[0122] In one implementation, the number T of time slots corresponding to the first duration can satisfy: Alternatively, it can be understood that the number of time slots corresponding to the first duration can be determined according to the above formula. Where, counter is the initial value of the random backoff counter (or the initial value of the random backoff counter selected by the terminal device during the first LBT process), 9e -3 Representing 9 microseconds, this is the smallest time granularity for channel resource sensing on unlicensed frequency bands. The terminal device determines whether the channel status is idle or busy within this time frame based on the sensing results. -μ The duration of a timeslot in the current communication system is expressed in microseconds, and μ corresponds to the subcarrier interval index. μ can also be understood as a parameter corresponding to the subcarrier interval; different subcarrier interval sizes can correspond to different values ​​of μ. For example, the correspondence between μ and the subcarrier interval can be seen in Table 2 above.

[0123] The time slots of the transmitting and receiving terminal devices are aligned, and both devices use resources at the time slot granularity, with the time slot representing the starting position of the resource. In the above formula, rounding allows the transmitting terminal device to send valid data at integer multiples of the time slot. Rounding can be interpreted as the index of the first complete time slot that the transmitting terminal device can use.

[0124] Optional, when (counter*9e -3 (Not 2) -μ When the value is an integer multiple of 2, or when the retreat is successful and the retreat counter decrements to 0, it is not 2. -μ When the value is an integer multiple of n, in order to preempt resources, the sending terminal device can send n+(counter*9e) -3 Between time n+T, placeholder information, redundant information, independent control information, or copy information of the first complete frame are sent.

[0125] Correspondingly, the number of time slots T1 between the starting time n+T1 of the resource selection window [n+T1, n+T2] and the time n that triggers resource selection satisfies:

[0126] exist In this case, The value of T1 is determined by the terminal device itself, and the range of T1 values ​​satisfies the following conditions: exist In this case, For example, the resource selection window can be like... Figure 10 As shown.

[0127] It is understood that this application embodiment only uses time slots as an example for illustration. In specific implementations, other time units can also be used, such as symbols, frames, subframes, half-frames, control information transmission intervals, etc. Taking time unit A as an example, the 2-μ involved in the number of time slots corresponding to the first duration, or the number of time slots between the start time point of the resource selection window and the time point that triggers resource selection, can be replaced with XXX, where XXX is the duration of time unit A in milliseconds, thus obtaining the number of time units A corresponding to the first duration, or the number of time units A between the start time point of the resource selection window and the time point that triggers resource selection. For example, when the subcarrier interval is 30kHz, time unit A is a subframe, and XXX is 0.5 milliseconds; or, for example, when the subcarrier interval is 30kHz, time unit A is a half-frame, and XXX is 0.25 milliseconds, and so on.

[0128] For example, the number 'a' of A corresponding to the first duration can satisfy: The number of time units A, a1, between the start time of the resource selection window and the time when resource selection is triggered can satisfy: In this case, exist In this case,

[0129] The number of time slots corresponding to the first duration or the number of time slots between the start time of the resource selection window and the time of triggering resource selection can also be processed similarly to obtain the number of time units A corresponding to the first duration or the number of time units A between the start time of the resource selection window and the time of triggering resource selection. Repeated parts will not be repeated.

[0130] Furthermore, in one specific implementation, when determining the first duration, the first interval in the first type of LBT can be considered. That is, the first duration can be determined based on the initial value of the random backoff counter corresponding to the first type of LBT and the first interval in the first type of LBT.

[0131] The first interval can be understood as the duration of channel idle time in the first type of LBT, that is, the duration of continuous channel idle time that the terminal device needs to wait for when performing LBT. The value of the interval differs in different types of LBTs. For example, in the first channel access method (corresponding to Cat 1 LBT in the WIFI protocol, or Type 2B LBT in the 3GPP protocol), the interval can be SIFS. In the second channel access method (corresponding to Cat 2 LBT in the WIFI protocol, or Type 2A LBT in the 3GPP protocol), the interval can be PIFS, and so on. In this embodiment, the first interval can be the DIFS duration in the WIFI protocol, or the first interval can also be the defer duration in the 3GPP protocol. It can be understood that the first interval can also be called the first duration, the first preset duration, etc.

[0132] Based on the above implementation scheme, the number T of time slots corresponding to the first duration can satisfy: Alternatively, it can be understood that the number of time slots corresponding to the first duration can be determined according to the above formula, where t is the first interval.

[0133] Correspondingly, the time slot T1 between the start time n+T1 of the resource selection window [n+T1, n+T2] and the time slot n that triggers resource selection satisfies: In this case, exist In this case, For example, the resource selection window can be like... Figure 11 As shown.

[0134] In a scheme where the terminal device determines the first duration without considering interruptions during the random backoff counter counting period, one implementation of step S902 is as follows: Transmission resources (or COTs) can be selected from a first resource set in chronological order. The first resource set is a subset of the candidate resource set in the resource selection window, and includes candidate resources in the resource selection window that are after the end time of the LBT. For example, the first resource set may include all candidate resources in the resource selection window that are after the end time of the LBT, or it may include only a portion of the candidate resources in the resource selection window that are after the end time of the LBT. The selected transmission resources can be as follows: Figure 12 or Figure 13 As shown.

[0135] The above implementation improves the LBT access success rate and increases the likelihood of communication on the selected resources by selecting resources in the resource selection window that are located after the LBT end time in a forward-to-back chronological order.

[0136] In a scheme where the terminal device determines the first duration considering an interruption during the random backoff counter counting period, the terminal device can first determine the reserved resources during the random backoff counter counting period (assuming there are N reserved resources). The terminal device determines the duration for which the random backoff counter is interrupted by these N reserved resources, and thus determines the first duration based on the initial value of the random backoff timer and the duration for which the random backoff counter is interrupted by these N reserved resources. That is, the first duration can be determined based on the random backoff counter corresponding to the first type of LBT and a second duration, where the second duration is the duration for which the random backoff counter corresponding to the first type of LBT is interrupted by these N reserved resources.

[0137] Because the random backoff counter is interrupted if another terminal device sends a signal in the same time slot during the random backoff process, the time required for LBT success increases. In the above scheme, by considering the duration of the random backoff counter interruption when determining the start time of the resource selection window, the LBT access success rate can be further improved, increasing the likelihood that the terminal device will send information on the resource selected within the resource selection window.

[0138] In one implementation, the second duration is the number of time slots occupied by N reserved resources. Then, the number of time slots T corresponding to the first duration can satisfy: Alternatively, it can be understood that the number of time slots corresponding to the first duration can be determined according to the above formula.

[0139] The parameters of counter and μ can be found in the previous description, and will not be repeated here. reservation i Let be the number of time slots occupied by the i-th reserved resource out of N reserved resources in the random backoff counter, where 1 ≤ i ≤ N. For example, if a reserved resource occupies 1 time slot, then the number of time slots corresponding to the second duration is N.

[0140] Correspondingly, the number of time slots T1 between the start time n+T1 of the resource selection window [n+T1, n+T2] and the time n that triggers resource selection satisfies: In this case, The value of T1 is determined by the terminal device itself, and the range of T1 values ​​satisfies the following conditions: exist In this case, For example, assuming N is 3, and one reserved resource occupies one time slot, the resource selection window can be as follows: Figure 14 As shown.

[0141] In another implementation, the second duration can be determined based on the number of time slots occupied by N reserved resources and N first intervals. Then, the number T of time slots corresponding to the first duration can satisfy: t represents the first interval. Alternatively, it can be understood that the number of time slots corresponding to the first duration can be determined according to the formula above.

[0142] Correspondingly, the number of time slots T1 between the start time n+T1 of the resource selection window [n+T1, n+T2] and the time n that triggers resource selection satisfies: In this case, The value of T1 is determined by the terminal device itself, and the range of T1 values ​​satisfies the following conditions: exist In this case,

[0143] The above example can improve the accuracy of the LBT time by taking into account the first interval after each interruption of reserved resources.

[0144] In the scheme for determining the first duration when the terminal device is interrupted during the random backoff counter counting, one implementation of step S902 is that a transmission resource (or a COT) can be selected from the candidate resource set in the resource selection window in chronological order. For example, the selected transmission resource can be as follows: Figure 15 As shown.

[0145] The above implementation method, by selecting resources in the resource selection window that are located after the end time of LBT in a forward-to-back chronological order, can increase the probability of successful LBT access before communication on the reserved resources, and increase the likelihood of communication on the selected resources.

[0146] The following section introduces the method for determining reserved resources.

[0147] In one possible implementation, the terminal device can detect SCIs within a resource listening window. If an SCI meets the following condition, the resource indicated by the SCI can be determined to be a reserved resource: the reference signal received power (RSRP) corresponding to the SCI is greater than a first threshold, where the first threshold is an RSRP threshold used for resource selection. For example, the first threshold can be a threshold used for resource exclusion in the user-selected resource mode (mode-2), and this threshold can be a function of the priority of the data indicated in the received SCI and the priority of the data to be transmitted by the terminal device.

[0148] In the user-selected resource mode (mode-2), when the RSRP corresponding to the SCI is greater than the first threshold, the resource indicated by the SCI is excluded from the candidate resource set corresponding to the resource selection window. In this embodiment, the RSRP of the SCI is compared with the first threshold. When the RSRP corresponding to the SCI is greater than the first threshold, it can be determined that the resource indicated by the SCI is a reserved resource for the interrupt random backoff counter.

[0149] In another implementation, the terminal device can detect the SCI within the resource listening window. If the SCI meets the following condition, the resource indicated by the SCI can be determined to be a reserved resource: the received signal strength indicator (RSSI) corresponding to the SCI is greater than a second threshold, where the second threshold is an RSSI threshold used for LBT. For example, the second threshold can be a threshold used to determine whether the channel is idle during the LBT process.

[0150] During LBT, when the RSSI corresponding to the SCI is greater than the second threshold, it can be determined that the channel is not idle. In this embodiment, the RSSI of the SCI is compared with the second threshold. When the RSSI corresponding to the SCI is greater than the second threshold, it can be determined that the resource indicated by the SCI is a reserved resource for the interrupt random backoff counter.

[0151] In another implementation, the terminal device can detect SCI within the resource listening window. If the SCI meets the following conditions, the resource indicated by the SCI can be determined to be a reserved resource: the RSRP corresponding to the SCI is greater than a first threshold, and / or the RSSI corresponding to the SCI is greater than a second threshold.

[0152] This implementation is a combination of the two implementations described above. The SCI is compared with the two conditions mentioned above (i.e., condition 1: RSRP is greater than the first threshold, condition 2: RSSI is greater than the second threshold). If the SCI satisfies either of the two conditions, it can be determined that the resource indicated by the SCI is a reserved resource for the interrupt random backoff counter.

[0153] Optionally, the resource indicated by SCI is a reserved resource for the interrupt random backoff counter. In addition to satisfying the conditions described in the three implementation methods above, the following condition is also met: the indicated reserved resource can be located before the PDB time.

[0154] Through the above three implementation methods, the terminal device can determine that if the M SCIs detected in the resource listening window meet the above conditions and the N reserved resources indicated by the M SCIs are located before the PDB time, then the N reserved resources indicated by the M SCIs can be used to determine the above first duration.

[0155] The methods for determining reserved resources have been described above. Below, we introduce possible methods for determining the first duration based on reserved resources. The first duration can be determined through the following process:

[0156] A1. Confirm whether there are reserved resources within the first time window. If yes, proceed to A2; otherwise, proceed to A3.

[0157] The first time window starts at the time point n when resource selection is triggered, and ends at the time point n, determined by the random backoff counter, specifically when the random backoff counter decrements to 0. The initial end position of the first time window is n + (counter * 9e) / (n + (counter * 9e) ...) / (n + (counter * 9e)))))))))))))))))))""))"")"" )"")" )"" 2.!"" The first time window starts at the time point n when resource selection is triggered, and ends at)))))") "" )"" ☐" ☐)"'" ☐)"'"* 9e"*" 95" 9——)—9 *""" 12 -3 +t). The method for determining the reserved resources within the first time window can be found in the previous text, and will not be repeated here.

[0158] Understandably, the first interval t can also be ignored in the above steps, meaning the initial end position of the first time window is n + (counter * 9e) -3 ).

[0159] A2 updates the end position of the first time window based on the reserved resources included within it. Execute A1.

[0160] Assume the first time window includes N j If a reserved resource is available, then the random backoff counter will be delayed by at least [number missing]. Among them, reservation i The random backoff counter is N j The number of time slots corresponding to the duration of the interruption of the i-th reserved resource in the reserved resources is then used to determine the end position of the first time window, considering the first interval t after the reserved resources are considered. Without considering the first interval t after reserving resources, the initial end position of the first time window is:

[0161] A3, determine the duration corresponding to the first time window as the first duration.

[0162] Optionally, when the terminal device needs to select more than one transmission resource (or occupy more than one COT) in the resource selection window, the transmission resources (or COTs) must satisfy the LBT (Local Best-Bottom) condition. For example, assuming the terminal device needs to occupy P COTs within the resource selection window, P random backoff count initial values ​​can be randomly generated at a first time point n. Based on one of the random backoff count initial values, the above scheme is used to determine the starting time point of the resource selection window and the occupation of the first COT. After occupying the first COT, the above scheme can be used again to determine the starting time point of the resource selection window and the occupation of the second COT based on another random backoff count initial value. And so on.

[0163] For example, in the embodiments of this application, the transmission resources selected by the terminal device can be in the frequency domain at the channel level, and in the time domain at the time unit level, such as time slots or COT, wherein COT includes multiple consecutive time slots.

[0164] In this embodiment, the start time of the resource selection window is determined based on the end time of the LBT (Low-Time Bypass) to ensure that as many resources as possible within the selection window are located after the LBT ends. This increases the probability of a successful LBT before communication on reserved resources, and increases the likelihood of the terminal device sending information on the resources selected within the selection window. With the solution provided in this embodiment, after receiving the indication information (indicating transmission resources or occupied COT) sent by the sending terminal device, the receiving terminal device can enter the receiving state at the position indicated by the indication information without needing to perform detection and reception between positions, thereby reducing the power consumption of the receiving terminal device.

[0165] This application provides a communication device. This communication device can be used to implement the functions of the terminal devices involved in the above embodiments. For example, the communication device can be the terminal device itself, such as an integrated terminal device like a vehicle-mounted terminal device or a roadside unit (RSU). Alternatively, the communication device can be a device that supports the terminal device in implementing this function, such as a chip, module, TBOX, or other combined device or component (or assembly) with the terminal device functions shown in this application. For example, the communication device can be a chip, module, or component within a vehicle-mounted terminal device or roadside unit. The communication device may include... Figure 7 and / or Figure 8 The structure shown.

[0166] This application also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a computer, the computer can implement the processes related to the terminal device described in the above embodiments.

[0167] This application also provides a computer program product for storing computer programs. When the computer program is executed by a computer, the computer can implement the processes related to the terminal device described in the above embodiments.

[0168] This application also provides a chip or chip system. The chip may include a processor, which can be used to call programs or instructions in memory to execute the processes related to the terminal device described above. The chip system may include the chip, as well as other components such as memory or transceivers.

[0169] This application also provides a circuit that can be coupled to a memory and can be used to execute the processes related to the terminal device described in the above embodiments. The chip system may include the chip itself, as well as other components such as a memory or a transceiver.

[0170] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0171] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0172] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0173] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0174] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method, characterized in that, The method includes: Determine the start time point of the resource selection window, wherein the time interval between the start time point of the resource selection window and the first time point is not less than the first duration, the first time point is the time point at which resource selection is triggered, and the first duration is the duration required for the terminal device to execute the first type of Listen-The-After-Speak LBT. Select the transmission resource in the resource selection window; Wherein, the first duration is determined based on the initial value of the random backoff counter corresponding to the first type of LBT; Alternatively, the first duration may be determined based on the initial value of the random backoff counter corresponding to the first type of LBT and the second duration; Wherein, the second duration is the number of time slots occupied by the N reserved resources, or the second duration is determined based on the number of time slots occupied by the N reserved resources and the N first intervals, the first interval is the channel idle duration after the corresponding reserved resource, and the first interval and the corresponding reserved resource are continuous in the time domain, the N reserved resources are the resources reserved within the first duration, and N is a positive integer.

2. The method as described in claim 1, characterized in that, The number of time slots corresponding to the time interval between the start time point and the first time point of the resource selection window. satisfy: exist In this case, ; and / or, exist In this case, ; Among them, the For a predefined first processing time, the This represents the number of time slots corresponding to the first duration.

3. The method as described in claim 1, characterized in that, The number of time slots T corresponding to the first duration satisfies: ； Among them, the The initial value of the random backoff counter is... Corresponding subcarrier spacing.

4. The method according to any one of claims 1-3, characterized in that, Selecting transmission resources within the resource selection window includes: Transmission resources are selected in a first resource set in chronological order from front to back, wherein the first resource set is a subset of the candidate resources in the resource selection window, and the first resource set includes candidate resources in the resource selection window that are located after the end time of LBT.

5. The method as described in claim 1, characterized in that, The number of time slots T corresponding to the first duration satisfies: ； Among them, the The initial value of the random backoff counter is... Corresponding to the subcarrier spacing, the The number of time slots occupied by the i-th reserved resource among the N reserved resources.

6. The method as described in claim 1, characterized in that, The number of time slots T corresponding to the first duration satisfies: ； Among them, the The initial value of the random backoff counter is... Corresponding to the subcarrier spacing, the The number of time slots occupied by the i-th reserved resource among the N reserved resources, where t is the first interval.

7. The method according to any one of claims 1, 2, 5, and 6, characterized in that, The N reserved resources are indicated by M side-by-side control messages within the resource monitoring window, where M is a positive integer; where, The Reference Signal Received Power (RSRP) corresponding to each of the M side-by-side control information is greater than a first threshold, where the first threshold is an RSRP threshold used for resource selection; or The Received Signal Strength Indicator (RSSI) corresponding to each of the M side-by-side control information is greater than a second threshold, where the second threshold is the RSSI threshold used for LBT; or The RSRP corresponding to each of the M lateral control information is greater than the first threshold, and the RSSI corresponding to each of the M lateral control information is greater than the second threshold.

8. A communication device, characterized in that, The device includes: The processing module is used to determine the start time point of the resource selection window, wherein the time interval between the start time point of the resource selection window and the first time point is not less than the first duration, the first time point is the time point that triggers resource selection, and the first duration is the duration required for the terminal device to execute the first type of Listen-The-After-Speak LBT. The processing module is also used to select transmission resources within the resource selection window; Wherein, the first duration is determined based on the initial value of the random backoff counter corresponding to the first type of LBT; Alternatively, the first duration may be determined based on the initial value of the random backoff counter corresponding to the first type of LBT and the second duration; Wherein, the second duration is the number of time slots occupied by the N reserved resources, or the second duration is determined based on the number of time slots occupied by the N reserved resources and the N first intervals, the first interval is the channel idle duration after the corresponding reserved resource, and the first interval and the corresponding reserved resource are continuous in the time domain, the N reserved resources are the resources reserved within the first duration, and N is a positive integer.

9. The apparatus as claimed in claim 8, characterized in that, The number of time slots corresponding to the time interval between the start time point and the first time point of the resource selection window. satisfy: exist In this case, ; and / or, exist In this case, ; Among them, the For a predefined first processing time, the This represents the number of time slots corresponding to the first duration.

10. The apparatus as claimed in claim 8, characterized in that, The number of time slots T corresponding to the first duration satisfies: ； Among them, the The initial value of the random backoff counter is... Corresponding subcarrier spacing.

11. The apparatus according to any one of claims 8-10, characterized in that, The processing module, when selecting a transmission resource in the resource selection window, is specifically used for: Transmission resources are selected in a first resource set in chronological order from front to back, wherein the first resource set is a subset of the candidate resources in the resource selection window, and the first resource set includes candidate resources in the resource selection window that are located after the end time of LBT.

12. The apparatus as claimed in claim 8, characterized in that, The number of time slots T corresponding to the first duration satisfies: ； Among them, the The initial value of the random backoff counter is... Corresponding to the subcarrier spacing, the The number of time slots occupied by the i-th reserved resource among the N reserved resources.

13. The apparatus as claimed in claim 8, characterized in that, The number of time slots T corresponding to the first duration satisfies: ； Among them, the The initial value of the random backoff counter is... Corresponding to the subcarrier spacing, the The number of time slots occupied by the i-th reserved resource among the N reserved resources, where t is the first interval.

14. The apparatus according to any one of claims 8, 9, 12, and 13, characterized in that, The N reserved resources are indicated by M side-by-side control messages within the resource monitoring window, where M is a positive integer; where, The Reference Signal Received Power (RSRP) corresponding to each of the M side-by-side control information is greater than a first threshold, where the first threshold is an RSRP threshold used for resource selection; or The Received Signal Strength Indicator (RSSI) corresponding to each of the M side-by-side control information is greater than a second threshold, where the second threshold is the RSSI threshold used for LBT; or The RSRP corresponding to each of the M lateral control information is greater than the first threshold, and the RSSI corresponding to each of the M lateral control information is greater than the second threshold.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program that, when run on a computer, causes the computer to perform the method as described in any one of claims 1 to 7.

16. A computer program product, characterized in that, It includes a computer program or instructions, characterized in that, when the computer program or instructions are executed by a processor, they implement the method described in any one of claims 1 to 7.

17. A chip, characterized in that, It includes a processor and a communication interface, wherein the processor is used to read instructions to execute the method according to any one of claims 1 to 7.

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