WO2025231668A1 - Methods for wireless communication, and terminal devices - Google Patents

Abstract

Provided are methods for wireless communication, and terminal devices. A method for wireless communication comprises: during the operation of a first timer, a terminal device executing a first operation upon triggering a first random access procedure, wherein the first operation comprises one or more of the following: determining a valid GNSS position of the terminal device; and on the basis of a TA adjustment amount maintained before the first random access procedure, determining a TA used in the first random access procedure, wherein during the operation of the first timer, the terminal device can perform uplink transmission after the GNSS position becomes invalid.

Description

Methods and terminal devices for wireless communication Technical Field

This application relates to the field of communication technology, and more specifically, to a method and terminal device for wireless communication.

Background Technology

In certain communication systems (such as non-terrestrial network (NTN) systems), if the Global Navigation Satellite System (GNSS) location of a terminal device fails, the terminal device can continue to use the failed GNSS location for uplink transmission for a certain period of time (e.g., during the operation of the T390 timer). However, during this period, initiating random access using the failed GNSS location is prone to random access failure.

Summary of the Invention

This application provides a method and terminal device for wireless communication. The various aspects covered in this application are described below.

In a first aspect, a method for wireless communication is provided, comprising: during the operation of a first timer, a terminal device performs a first operation upon triggering a first random access procedure, the first operation comprising one or more of the following: determining a valid GNSS location of the terminal device; determining a TA used in the first random access procedure based on a TA adjustment amount maintained prior to the first random access procedure; wherein, during the operation of the first timer, the terminal device is capable of uplink transmission after the GNSS location fails.

In a second aspect, a method for wireless communication is provided, comprising: during the operation of a first timer, if a terminal device receives a RACH-less handover command sent by a network device, and the handover command indicates that the target cell and the source cell use the same TA adjustment amount, the terminal device continues to run the first timer; wherein, during the operation of the first timer, the terminal device is capable of uplink transmission after GNSS location failure.

Thirdly, a terminal device is provided, comprising: an execution module configured to perform a first operation when a first random access procedure is triggered during the operation of a first timer, the first operation comprising one or more of the following: determining a valid GNSS location of the terminal device; determining a TA used in the first random access procedure based on a TA adjustment amount maintained prior to the first random access procedure; wherein, during the operation of the first timer, the terminal device is capable of uplink transmission after the GNSS location fails.

Fourthly, a terminal device is provided, comprising: an operation module, configured to continue running the first timer if, during the operation of a first timer, the terminal device receives a RACH-less handover command sent by a network device, and the handover command instructs the target cell and the source cell to use the same TA adjustment amount; wherein, during the operation of the first timer, the terminal device is capable of uplink transmission after GNSS location failure.

Fifthly, a terminal device is provided, including a processor and a memory, wherein the memory is used to store one or more computer programs, and the processor is used to invoke the computer programs in the memory to cause the terminal device to perform some or all of the steps in the method of the first or second aspect.

Sixthly, embodiments of this application provide a communication system including the aforementioned terminal device. In another possible design, the system may further include other devices that interact with the terminal device as described in the embodiments of this application.

In a seventh aspect, embodiments of this application provide a computer-readable storage medium storing a computer program that causes a computer to perform some or all of the steps in the methods described above.

Eighthly, embodiments of this application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of the methods described in the foregoing aspects. In some implementations, the computer program product may be a software installation package.

Ninthly, embodiments of this application provide a chip including a memory and a processor, the processor being able to call and run a computer program from the memory to implement some or all of the steps described in the methods of the foregoing aspects.

In this embodiment, during the time when the terminal device can use a failed GNSS location for uplink transmission, if the terminal device triggers a first random access procedure, the terminal device can determine a valid GNSS location, or the terminal device can determine the TA used in the first random access procedure based on the TA adjustment amount maintained before the first random access procedure. In this way, the terminal device can perform random access based on a valid GNSS location or the TA adjustment amount maintained before the first random access procedure, which helps improve the success rate of random access.

Attached Figure Description

Figure 1 is a system architecture example diagram of a wireless communication system applicable to embodiments of this application.

Figure 2 is an example diagram of the NTN network architecture with transparent forwarding.

Figure 3 is an example diagram of the NTN network architecture for regeneration and forwarding.

Figure 4A is an example diagram showing the delay of uplink signals arriving at network devices when TA is absent.

Figure 4B is an example diagram showing the delay of uplink signals arriving at network devices when TA is present.

Figure 5 is a flowchart illustrating a method for wireless communication provided in an embodiment of this application.

Figure 6 is an example diagram of performing the first operation.

Figure 7 is a flowchart illustrating a method for wireless communication provided in another embodiment of this application.

Figure 8 is a schematic diagram of the structure of a terminal device provided in an embodiment of this application.

Figure 9 is a schematic diagram of the structure of a terminal device provided in another embodiment of this application.

Figure 10 is a schematic structural diagram of the communication device provided in an embodiment of this application.

Detailed Implementation

Communication system architecture

The technical solutions of this application embodiment can be applied to various communication systems, such as: Global System for Mobile Communication (GSM), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), General Packet Radio Service (GPRS), Long Term Evolution (LTE), Advanced Long Term Evolution (LTE-A), New Radio (NR), and NR systems. The evolution of traditional systems, LTE (LTE-based access to unlicensed spectrum, LTE-U) systems on unlicensed spectrum, NR (NR-based access to unlicensed spectrum, NR-U) systems on unlicensed spectrum, NTN systems, universal mobile telecommunications system (UMTS), wireless local area networks (WLAN), wireless fidelity (WiFi), 5th-generation (5G) systems or other communication systems, such as future communication systems, such as 6th generation mobile communication systems, or satellite communication systems, etc.

Traditional communication systems typically support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communication but also, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, or vehicle-to-everything (V2X) communication. The embodiments of this application can also be applied to these communication systems.

The communication system in this application embodiment can be applied to carrier aggregation (CA) scenarios, dual connectivity (DC) scenarios, and standalone (SA) network deployment scenarios.

The communication system in this application embodiment can be applied to unlicensed spectrum, which can also be considered as shared spectrum; or, the communication system in this application embodiment can also be applied to licensed spectrum, which can also be considered as dedicated spectrum.

The embodiments of this application can be applied to NTN systems and terrestrial network (TN) systems. By way of example and not limitation, NTN systems include NR-based NTN systems and Internet of Things (IoT)-based NTN systems. For example, in scenarios where narrowband Internet of Things (NB-IoT) and enhanced machine-type communication (eMTC) access NTN, the system composed of IoT terminal devices and the NTN network can be understood as an IoT-based NTN system.

This application describes various embodiments in conjunction with network devices and terminal devices. The terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user equipment, etc.

In the embodiments of this application, the terminal device may be a station (ST) in a WLAN, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a next-generation communication system such as an NR network, or a terminal device in a future evolved public land mobile network (PLMN) network, etc.

In the embodiments of this application, the terminal device can be a device that provides voice and/or data connectivity to the user, and can be used to connect people, objects, and machines, such as handheld devices with wireless connectivity, in-vehicle devices, etc. The terminal device in the embodiments of this application can be a mobile phone, tablet computer, laptop computer, PDA, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc. Optional In this context, terminal devices can act as base stations. For example, a terminal device can act as a scheduling entity, providing sidelink signaling between terminal devices in V2X or D2D, etc. For instance, cellular phones and cars communicate with each other using sidelink signals. Cellular phones and smart home devices can communicate without relaying communication signals through a base station.

The network device in this application embodiment can be a device for communicating with a terminal device. This network device can also be called an access network device or a wireless access network device, such as a base station. In this application embodiment, the network device can refer to a radio access network (RAN) node (or device) that connects the terminal device to the wireless network. A base station can broadly encompass, or be replaced by, various names including: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, transmitting and receiving point (TRP), transmitting point (TP), master MeNB, secondary SeNB, multi-mode radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, micro base station, relay node, donor node, or similar entities, or combinations thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in D2D, V2X, and M2M communications, a network-side device in a 6G network, or a device that performs base station functions in future communication systems. A base station can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

In some deployments, the network device in this application embodiment may refer to a CU or a DU, or the network device may include both a CU and a DU. The gNB may also include an AAU.

Network devices and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and satellites. This application does not limit the scenario in which the network devices and terminal devices are located.

By way of example and not limitation, in the embodiments of this application, the network device may have mobility characteristics; for example, the network device may be a mobile device. In some embodiments of this application, the network device may be a satellite or a balloon station. For example, the satellite may be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. In some embodiments of this application, the network device may also be a base station located on land, water, or other similar locations.

In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

For example, Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of this application. As shown in Figure 1, the communication system 100 may include a network device 110 and a terminal device 120. The network device 110 may be a device that communicates with the terminal device 120 (or a communication terminal, terminal). The network device 110 may provide communication coverage for a specific geographical area and may communicate with terminal devices located within that coverage area. For example, the network device may be a satellite.

Figure 1 illustrates an exemplary network device and two terminal devices. In some embodiments of this application, the communication system 100 may include multiple network devices and each network device may include other numbers of terminal devices within its coverage area. This application does not limit this aspect.

It should be noted that Figure 1 is only an example illustrating the system to which this application applies. Of course, the method shown in the embodiments of this application can also be applied to other systems, such as 5G communication systems, LTE communication systems, etc., and the embodiments of this application do not specifically limit this.

In some embodiments of this application, the wireless communication system shown in FIG1 may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), which are not limited in this application.

As described above, the technical solutions provided in this application can be applied to NTN systems. For ease of understanding, some related technical knowledge (e.g., NTN network architecture) involved in the embodiments of this application will be introduced first. The following related technologies are optional solutions and can be arbitrarily combined with the technical solutions of the embodiments of this application, all of which fall within the protection scope of the embodiments of this application. The embodiments of this application include at least some of the following contents.

NTN

The 3rd Generation Partnership Project (3GPP) is currently researching NTN technology. NTN— Satellite communication is generally used to provide communication services to ground users. Compared with terrestrial communication networks (such as terrestrial cellular communication), satellite communication has many unique advantages.

First, satellite communication is not limited by the user's geographical location. For example, conventional terrestrial communication networks cannot cover areas such as oceans, mountains, and deserts where network equipment cannot be deployed. Alternatively, terrestrial communication networks cannot cover certain areas that are sparsely populated and therefore not covered. However, with satellite communication, since a single satellite can cover a large area of the Earth, and satellites orbit the Earth, theoretically, every corner of the Earth can be covered by satellite communication networks.

Secondly, satellite communication has significant social value. It can reach remote mountainous areas and impoverished, underdeveloped countries or regions at a relatively low cost, enabling people in these areas to enjoy advanced voice communication and mobile internet technologies. From this perspective, satellite communication helps bridge the digital divide with developed regions and promotes development in those areas.

Secondly, satellite communication has a long range, and the communication cost does not increase significantly with the increase in communication distance.

Finally, satellite communication is highly stable and unaffected by natural disasters.

Communication satellites can be classified according to their orbital altitude, such as LEO satellites, MEO satellites, GEO satellites, and HEO satellites. Currently, research primarily focuses on LEO and GEO satellites.

LEO satellites typically operate at altitudes ranging from 500 km to 1500 km. Correspondingly, their orbital periods are approximately 1.5 to 2 hours. For LEO satellites, the signal propagation delay for single-hop communication between users is generally less than 20 ms. The maximum visible time for LEO satellites is approximately 20 minutes. LEO satellites offer advantages such as short signal propagation distances, low link loss, and low requirements for the transmission power of terminal equipment.

The GEO satellite orbits at an altitude of approximately 35,786 km. Its orbital period around the Earth is 24 hours. For GEO satellites, the signal propagation delay for single-hop communication between users is typically around 250 ms.

To ensure satellite coverage and enhance the overall capacity of the satellite communication system, satellites typically employ multi-beam coverage of ground areas. Therefore, a single satellite can generate dozens or even hundreds of beams to cover a ground area. One satellite beam can typically cover a ground area with a diameter of tens to hundreds of kilometers.

Currently, NTN systems can include NR NTN systems and IoT NTN systems.

NTN network architecture

The NTN network architecture can include the following network elements: gateway, feeder link, service link, and satellite.

An NTN network architecture may include one or more gateways, which can be used to connect satellite and terrestrial public networks.

A feeder link can refer to the communication link between a gateway and a satellite.

A service link can refer to the communication link between a terminal device and a satellite.

From the perspective of the functions provided by satellites, they can be divided into transparent payload satellites and regenerative payload satellites. Transparent payload satellites only provide radio frequency filtering, frequency conversion, and amplification functions. In other words, transparent payload satellites only provide transparent signal forwarding without altering the waveform of the forwarded signal. Regenerative payload satellites, in addition to providing radio frequency filtering, frequency conversion, and amplification functions, can also provide one or more of the following functions: demodulation, decoding, routing, conversion, encoding, modulation, etc. Regenerative payload satellites can have some or all of the functions of a base station. Based on the different functions provided by satellites in the NTN network, the NTN network architecture can be divided into transparent payload NTN network architecture and regenerative payload NTN network architecture. Figures 2 and 3 show example diagrams of transparent payload NTN network architecture and regenerative payload NTN network architecture, respectively.

In some embodiments, the NTN network architecture may also include inter-satellite links (ISLs). For example, inter-satellite links may exist in a regenerable forwarding NTN network architecture.

Timing advance (TA) in TN

A key characteristic of uplink transmission is orthogonal multiple access in time and frequency domains (OMG), meaning that uplink transmissions from different terminal devices within the same cell do not interfere with each other. To ensure the orthogonality of uplink transmissions and avoid intra-cell interference, network devices require that signals from different terminal devices originating from the same time but using different frequency domain resources arrive at the network device at essentially the same time. To ensure time synchronization on the network device side, communication systems (e.g., LTE/NR) can support uplink time synchronization (TA) mechanisms.

In communication systems supporting uplink TA (Transmission Time Acquisition), the uplink and downlink clocks on the network device side are identical, while there is an offset between the uplink and downlink clocks on the terminal device side, and different terminal devices have their own different uplink TA values. By appropriately controlling the offset of each terminal device, the network device can control the arrival time of uplink signals from different terminal devices. For terminal devices farther from the network device, due to the larger transmission delay, they must send uplink data earlier than terminal devices closer to the network device.

Network devices can determine the TA value of each terminal device by measuring the uplink transmissions of the terminal devices. Network devices can send TA commands to terminal devices to notify them of their corresponding TA values. For example, network devices can send TA commands to terminal devices in two ways, as follows:

Method 1, Obtaining the Initial TA: During the random access process, the network device can obtain the TA by measuring the received preamble. The TA value is determined and sent to the terminal device via the Timing Advance Command field of the random access response (RAR) message.

Method 2, Adjustment of TA in RRC Connection State: Although the terminal device and network device achieve uplink synchronization during random access, the timing of the uplink signal arriving at the network device may change over time. Therefore, the terminal device needs to continuously update its uplink TA to maintain uplink synchronization. If the TA of a terminal device needs correction, the network device can send a TA command (Timing Advance Command) to the terminal device, requesting it to adjust the uplink timing. In some implementations, this TA command is sent by the network device to the terminal device through the media access control element (MAC CE). This MAC CE can also be called a TA command MAC CE (i.e., a MAC CE carrying a TA command).

TA in NTN

As described above, in traditional TN networks, terminal devices can maintain their TA (Task Authority) based on TA commands issued by network devices. Similar to TN systems, in NTN systems (such as release 17, R17), terminal devices also need to consider the impact of TA during uplink transmission. In NTN systems, terminal devices typically possess GNSS positioning and TA pre-compensation capabilities, allowing them to estimate the TA corresponding to the service link based on their own location and the location of the serving satellite. As an implementation method, NTN introduces a combination of open-loop and closed-loop TA determination. Based on current standardization conference conclusions, for terminal devices in RRC idle state (RRC_IDLE), RRC inactive state (RRC_INACTIVE), and RRC connected state (RRC_CONNECTED), the TA of a terminal device accessing the NTN can be calculated using the following formula:
T _TA =(N _TA +N _{TA,UE-specific} +N _TA,common +N _TA,offset )×T _c

Here, _TTA refers to the TA of the terminal device accessing the NTN. _NTA is the TA adjustment amount controlled by the network device. For scenarios transmitted via the physical random access channel (PRACH), it is defined as 0 and can be updated subsequently through the TA command in message 2 (Msg2) or message B (MsgB) and the TA command MAC CE. _{NTA, UE-specific} is the TA (or service link TA) estimated by the terminal device itself for the service link, used for TA pre-compensation. As one implementation, the terminal device can determine the satellite's position based on its acquired GNSS location information combined with the satellite ephemeris information broadcast by the serving cell, thereby calculating the propagation delay of the service link from the terminal device to the satellite. _{NTA, common} is the common TA controlled by the network device, containing any timing deviations deemed necessary by the network, such as the TA corresponding to the feeder link, or other values. _{NTA, offset} is a preset offset value, such as a fixed offset value used to calculate the TA.

As can be seen from the above formula, for a terminal device accessing the NTN (e.g., an NTN terminal device in RRC connection state) to obtain the TA (i.e., _{NTA, UE-soecific} ) corresponding to the serving link, it needs to know its own GNSS location information and the location of the serving satellite through the serving cell's satellite ephemeris information. Furthermore, in order to calculate the terminal device's TA, the UE also needs to obtain the common TA (i.e., _{NTA, common} ).

GNSS operation of IoT NTN

In IoT NTN (e.g., scenarios where NB-IoT and eMTC terminal devices access the NTN), the GNSS measurement module and communication module of the IoT terminal device cannot operate simultaneously. In R17 IoT NTN, IoT terminal devices can only perform GNSS measurements in RRC idle or RRC inactive states to obtain GNSS location information; the GNSS module cannot be activated in RRC connected state. Therefore, before entering RRC connected state, the terminal device needs to measure and obtain its own GNSS location using the GNSS module. Then, the terminal device can determine the effective duration of this GNSS location based on its own situation (e.g., the device's movement status) and report the remaining effective time corresponding to the GNSS location to the network during RRC connection establishment/RRC reconstruction/RRC connection restoration. For terminal devices in RRC connected state, when their GNSS location expires, the terminal device cannot perform GNSS operations in RRC connected state. Therefore, the terminal device cannot perform certain subsequent operations based on the GNSS location information, such as calculating TA. In this case, the terminal device needs to return to RRC idle state to perform GNSS operations.

Release 18 (R18) proposes enhancements to IoT NTN performance to address legacy issues from R17. R18's enhancements to IoT NTN performance are based on the results of R17 NR-NTN, using R17 IoT-NTN as a baseline. Further goals for enhancing IoT-NTN performance are as follows: (1) Disabling HARQ feedback to mitigate the impact of HARQ stalling on UE data rates; (2) If necessary, studying and specifying improved GNSS operations for a new position fix for UE pre-compensation during long connection times and for reduced power consumption.

Based on the above research objectives, R18 discusses how IoT terminal devices connected to NTN can perform GNSS measurements or GNSS operations (or, as understood, obtain GNSS position information, etc.) in RRC connected state.

Furthermore, network devices can be configured with uplink transmission extension. This means that when a terminal device's GNSS location becomes unavailable, the terminal device can start a T390 timer. During the T390 timer's operation, the terminal device can continue to use the unavailable GNSS location for uplink transmission. In some implementations, the terminal device can restart the T390 timer after receiving an instruction from the MAC layer to extend uplink transmission. Timer. In some implementations, the terminal device stops the T390 timer and performs GNSS measurements when it receives a GNSS measurement triggered by the network device. In other implementations, when the T390 timer expires and the terminal device does not receive a GNSS measurement triggered by the network device, if the terminal device is configured to autonomously initiate GNSS measurements, it can perform GNSS measurements using an automatic gap; otherwise, the terminal device leaves the RRC connected state and enters the RRC idle state.

As can be seen from the description above, the GNSS location of the terminal device is invalid during the T390 timer operation. However, the terminal device can continue to use the invalid GNSS location during the T390 timer operation because the network device can adjust the TA (e.g., adjust the _NTA ) based on previous uplink transmissions.

However, during the operation of the T390 timer, the terminal device may trigger a random access procedure. In this case, if the terminal device initiates random access using an invalid GNSS location, it is likely to lead to random access failure.

To address the aforementioned problems, this application provides a method and terminal device for wireless communication. During the time when the terminal device can use a failed GNSS location for uplink transmission, the terminal device can determine a valid GNSS location when triggering the first random access procedure, so as to perform random access based on the valid GNSS location, or determine the TA used in the first random access procedure based on the TA adjustment amount maintained before the first random access procedure, which helps to improve the success rate of random access. The following describes embodiments of the method of this application.

Figure 5 is a schematic flowchart of a method for wireless communication provided in an embodiment of this application. The method shown in Figure 5 can be executed by a terminal device, which can be any of the terminal devices in Figures 1-3.

In some embodiments, the terminal device may refer to a terminal device that accesses the NTN.

In some embodiments, the terminal device may refer to a terminal device in an RRC connection state.

As an example, the terminal device can be a terminal device that is connected to the NTN and is in RRC connection state.

In some embodiments, the terminal device may be an IoT terminal device. For example, the terminal device may be an IoT terminal device that is connected to an NTN.

The method shown in Figure 5 includes step S510, which will be described below.

In step S510, during the operation of the first timer, the terminal device performs a first operation when the first random access procedure is triggered.

In this embodiment of the application, during the operation of the first timer, the terminal device is able to perform uplink transmission after the GNSS location fails. Alternatively, during the operation of the first timer, the terminal device is able to use (or continue to use) the failed GNSS location for uplink transmission. In some embodiments, the failure of the terminal device's GNSS location can be understood or replaced as the GNSS location of the terminal device being unavailable. In some embodiments, the failure of the terminal device's GNSS location can be understood as the GNSS location of the terminal device deviating significantly from its actual current location, resulting in large errors when using that GNSS location for operations (such as transmission, calculation, etc.).

In some embodiments, the first timer is started or restarted after the GNSS location of the terminal device fails. Alternatively, in some embodiments, the start or restart of the first timer is triggered based on the failure of the GNSS location of the terminal device.

In some embodiments, the first timer is a T390 timer.

In some embodiments, if the terminal device receives an indication to extend the uplink transmission while running the first timer, the terminal device may restart the first timer.

In some embodiments, when the first timer expires and no GNSS measurement is received triggered by the network device, the terminal device may autonomously initiate GNSS measurement or leave the RRC connected state. For example, when the first timer expires and no GNSS measurement is received triggered by the network device, if the terminal device is configured to autonomously initiate GNSS measurement (or has the capability to autonomously initiate GNSS measurement), the terminal device may perform GNSS measurement using automatic intervals; otherwise, the terminal device may leave the RRC connected state.

In some embodiments, after leaving the RRC connected state, the terminal device can enter the RRC idle state. For example, when the first timer times out and the terminal device is not configured to autonomously initiate GNSS measurements, the terminal device can leave the RRC connected state and enter the RRC idle state.

This application does not limit the triggering method of the first random access procedure. Exemplarily, the first random access procedure may be triggered based on one or more of the following: scheduling request (SR), cell handover, the terminal device being out of sync with uplink or downlink data arrival, or the terminal device lacking physical uplink control channel (PUCCH) resources for SR when uplink data arrives. Of course, the first random access procedure may also be triggered by other triggering methods introduced in the communication system. This application does not limit this; for example, the first random access procedure may be triggered by a new triggering method introduced in a future communication system, or by other unlisted triggering methods introduced in an existing communication system.

In this embodiment of the application, the first operation can be used to determine the TA used by the terminal device during random access. For example, the first operation can be used to determine the TA used in the first random access process. Alternatively, the first operation can be used to determine the TA used in a random access process after the first random access process (e.g., the next random access process after the first random access process).

In some embodiments, after the terminal device determines the TA to be used for random access using the first operation, it can use the TA to perform random access. For example, the terminal device can use the TA to send a preamble. Alternatively, the terminal device can use the TA to send a message carrying a preamble, such as sending message 1 (Msg1) or message A (MsgA), etc.

The first operation will be described in detail below with reference to Embodiment 1 and Embodiment 2.

Example 1:

Example 1 aims to determine (redetermine) the valid GNSS location of a terminal device so that the terminal device can perform random access based on the valid GNSS location, thereby improving the success rate of random access. In some embodiments, the valid GNSS location of the terminal device can also be understood or replaced as the available GNSS location of the terminal device, or in other words, the valid GNSS location of the terminal device can be understood or replaced as the available GNSS location of the terminal device. In some embodiments, the valid GNSS location of the terminal device can be understood as the GNSS location of the terminal device being relatively accurate relative to the actual current location of the terminal device, and the error generated when using the GNSS location for operations (such as transmission, calculation, etc.) is small.

In Embodiment 1, the first operation may include: determining the valid GNSS location of the terminal device. That is, in Embodiment 1, during the operation of the first timer, when the first random access procedure is triggered, the terminal device may determine (or re-determine, acquire) the valid GNSS location of the terminal device, so as to perform random access based on the determined valid GNSS location.

This application does not limit the implementation method of determining the effective GNSS location of the terminal device. Several implementation methods are described below as examples.

Implementation method 1: The terminal device considers the first timer to have expired, and performs GNSS measurement in the event of the first timer expiration.

It should be understood that in implementation method 1, during the operation of the first timer, when the terminal device triggers the first random access procedure (e.g., a random access procedure triggered by SR), it will consider (or determine, understand, or treat as, etc.) that the first timer has timed out. In this way, during the operation of the first timer, when the terminal device triggers the first random access procedure, it can handle the situation as if the first timer has timed out, for example, performing GNSS measurements if the first timer has timed out.

In some embodiments, the phrase "perform GNSS measurement" mentioned in this application can also be understood or replaced with "determine the valid GNSS position of the terminal device". This is because, in this application, the purpose of the terminal device performing GNSS measurement is to determine the valid GNSS position of the terminal device. The phrase "perform GNSS measurement" mentioned below can all be understood or replaced with "determine the valid GNSS position of the terminal device", and for the sake of brevity, it will not be repeated hereafter.

In some embodiments, if the terminal device believes that the first timer has expired, and if the terminal device receives a GNSS measurement triggered by the network device, the terminal device performs the GNSS measurement based on the network device's instruction.

In some embodiments, if the terminal device determines that the first timer has expired, and if the capability to autonomously initiate GNSS measurements is configured, the terminal device will autonomously initiate GNSS measurements. As another implementation, if autonomous GNSS measurements are configured, the terminal device can perform GNSS measurements using automatic gaps; in other words, the terminal device can perform GNSS measurements within automatic gaps.

In some embodiments, if the terminal device determines that the first timer has expired, and if it is not configured to autonomously initiate GNSS measurements, the terminal device can leave the RRC connected state and/or enter the RRC idle state. In this way, the terminal device can perform GNSS measurements before the next RRC connection is established to obtain a valid GNSS location for the terminal device.

In some embodiments, if the terminal device believes that the first timer has expired, and if the terminal device has not received a GNSS measurement triggered by the network device, and the terminal device is configured to autonomously initiate GNSS measurement, then the terminal device may autonomously initiate GNSS measurement; otherwise, the terminal device may leave the RRC connected state or enter the RRC idle state.

To facilitate understanding, an example of implementation method 1 is given below with reference to Figure 6.

As shown in Figure 6, the terminal device starts or restarts the first timer at time t1 (for example, the GNSS position of the terminal device becomes invalid from time t1). During the operation of the first timer, the terminal device triggers a random access procedure at time t2 (such as triggering the first random access procedure). At this time, the duration of the first timer has not yet ended. In this case, the terminal device will consider the first timer to have timed out at time t2 and perform subsequent operations according to the timer timeout. For example, the terminal device may start performing autonomous GNSS measurements or leave the RRC connected state (enter the RRC idle state) from time t2.

Implementation Method 2: The terminal device triggers RRC connection re-establishment, and performs GNSS measurements before starting the RRC connection re-establishment.

It should be understood that in implementation method 2, during the first timer operation, the terminal device triggers RRC connection re-establishment when it triggers the first random access procedure. In this way, during the first timer operation, the terminal device can perform GNSS measurements before initiating RRC connection re-establishment (e.g., before sending the RRC connection re-establishment request) to obtain a valid GNSS position. That is, the terminal device can obtain a valid GNSS position by reusing GNSS measurements taken before the RRC connection re-establishment by triggering the RRC connection re-establishment.

In some embodiments, the first random access procedure may be triggered by the SR. For example, during the execution of the first timer, the terminal device may trigger an RRC connection reconstruction when it triggers the first random access procedure based on the SR.

In some embodiments, the first random access procedure may be triggered by cell handover. For example, during the execution of a first timer, while the terminal device is performing a cell handover, an RRC connection re-establishment may be triggered, and GNSS measurements may be performed before the RRC connection re-establishment begins.

As an example, during the first timer run, if the network device triggers a cell handover (e.g., the network device sends a handover command), the terminal device can trigger an RRC connection re-establishment and perform GNSS measurements before starting the RRC connection re-establishment.

As another example, during the first timer run, if the terminal device meets the execution conditions for conditional switching, the terminal device can trigger RRC connection reconstruction and perform GNSS measurements before starting RRC connection reconstruction.

Implementation method 3: The terminal device enters the RRC idle state and performs GNSS measurements before the next RRC connection is established.

It should be understood that in implementation method 3, during the first timer operation, the terminal device will leave the RRC connected state and/or enter the RRC idle state when triggering the first random access procedure (e.g., a random access procedure triggered by SR). In this way, during the first timer operation, the terminal device can perform GNSS measurements before the next RRC connection is established to obtain a valid GNSS position. That is, the terminal device can reuse GNSS measurements taken before the RRC connection is established to obtain a valid GNSS position by leaving the RRC connected state or entering the RRC idle state.

Example 2:

The inventors discovered that during the time a terminal device can use a failed GNSS location for uplink transmission (e.g., during the first timer's operation), the reason why initiating random access using a failed GNSS location often leads to random access failure is that existing protocols stipulate that the TA adjustment amount during the random access process is 0. As a result, the terminal device cannot use the TA adjustment amount to adjust the TA used during the random access process. Based on this, Embodiment 2 aims to utilize the TA adjustment amount to adjust the TA used during the random access process, thereby improving the accuracy of the TA used during random access and thus increasing the success rate of random access.

In Example 2, the first operation includes determining the TA used in the first random access procedure based on the TA adjustment amount maintained before the first random access procedure. That is, during the first timer's operation, the terminal device can determine the TA used in the first random access procedure based on the TA adjustment amount maintained before the first random access procedure when triggering the first random access procedure. In this way, the terminal device can use a deactivated GNSS location for random access. The reason the terminal device can use a deactivated GNSS location for random access is that, when the terminal device uses the TA adjustment amount maintained before the first random access procedure to determine the TA used in the first random access procedure, the network device can adjust the TA adjustment amount based on previous uplink transmissions. In other words, Example 2 can ensure that a deactivated GNSS location can be used in the random access procedure by changing the TA adjustment amount used during random access.

In some embodiments, the TA adjustment amount maintained before the first random access procedure can be understood as the latest (most recently maintained) TA adjustment amount maintained before the first random access procedure was triggered. However, the embodiments of this application are not limited to this. For example, the TA adjustment amount maintained before the first random access procedure can also be understood as a certain TA adjustment amount maintained within a certain period of time before the first random access procedure was triggered, such as the most recently maintained TA adjustment amount, the TA adjustment amount maintained before the most recently maintained TA adjustment amount, etc.

In some embodiments, the TA adjustment amount used by the terminal device is controlled by the network device.

In some embodiments, the TA adjustment amount is maintained by the terminal device based on the TA command sent by the network device. This application does not limit the method by which the network device sends the TA command. In some implementations, the network device can send the TA command via Msg 2 or Msg B during the random access procedure. In some implementations, the network device can send the TA command via TA command MAC CE (TA command MAC CE).

In some embodiments, the TA adjustment amount is determined based on the TA amount carried in the TA command sent by the network device. For example, the TA adjustment amount is the cumulative value of the TA amounts carried in multiple TA commands sent by the network device. In other words, the TA adjustment amount can be an absolute value, which is determined based on the TA amount (relative value) carried in the TA command sent by the network device.

In some embodiments, the TA adjustment amount is a non-zero value.

In some embodiments, the TA used in the first random access procedure is determined based on one or more of the following: TA adjustment amount, serving link TA determined by the terminal device, common TA, and TA offset value. For example, the TA used in the first random access procedure can be determined by the following formula:
T _TA =(N _TA +N _{TA,UE-specific} +N _TA,common +N _TA,offset )×T _c

Here, _TTA refers to the TA used in the first random access procedure. _NTA is the TA adjustment amount. _{NTA, UE-specific,} is the TA corresponding to the serving link (or serving link TA) estimated by the terminal equipment itself, used for TA pre-compensation. _{NTA, common,} is the common TA controlled by the network equipment, which includes any timing deviations deemed necessary by the network, such as the TA corresponding to the feeder link, or other values. _{NTA, offset} is a preset offset value, such as a fixed offset value used to calculate the TA.

In some embodiments, the _NTA can be updated via the TA command in Msg2 or MsgB and the TA command MAC CE.

In some embodiments, the TA adjustment amount mentioned in this application refers to the aforementioned _NTA . For example, the TA adjustment amount maintained before the first random access procedure may refer to the _NTA maintained before the first random access procedure is triggered.

In Example 2, if a random access procedure is triggered during the first timer operation, the terminal device can use the previously maintained TA adjustment value when sending the preamble (unlike existing protocols, which stipulate that the TA adjustment value used when sending the preamble during random access is 0). In this way, the terminal device can use a deactivated GNSS location for random access during the first timer operation.

It should be understood that Embodiment 2 requires changing the TA adjustment amount used in the preamble transmission to ensure that the terminal device can use a failed GNSS location for random access. The following describes a scheme where the terminal device can directly use a failed GNSS location for random access, in conjunction with Embodiment 3.

Example 3:

Example 3 can be applied to RACH-less switching scenarios.

Figure 7 is a flowchart illustrating a method for wireless communication according to another embodiment of this application. The method shown in Figure 7 can be executed by a terminal device, which can be any of the terminal devices shown in Figures 1-3.

In some embodiments, the terminal device may refer to a terminal device that accesses the NTN.

In some embodiments, the terminal device may refer to a terminal device in an RRC connection state.

As an example, the terminal device can be a terminal device that is connected to the NTN and is in RRC connection state.

In some embodiments, the terminal device may be an IoT terminal device. For example, the terminal device may be an IoT terminal device that is connected to an NTN.

The method shown in Figure 7 includes step S710. In step S710, during the operation of the first timer, if the terminal device receives a RACH-less handover command sent by the network device, and the handover command indicates that the target cell and the source cell use the same TA adjustment amount, the terminal device continues to run the first timer.

For a brief introduction to the first timer and the TA adjustment amount, please refer to the previous text. For the sake of brevity, it will not be repeated here.

In some embodiments, when the target cell and the source cell belong to the same satellite, the target cell and the source cell can use the same TA adjustment amount. Alternatively, in some embodiments, RACH-less handover using the same TA adjustment amount primarily targets cell handovers within the same satellite. In this way, the target cell can continue to use the TA adjustment amount made to the terminal device by the source cell, and thus the terminal device can continue to use the invalid GNSS location within the target cell.

In some embodiments, during the operation of the first timer, if the terminal device receives a RACH-less handover command from the network device, but the handover command indicates that the target cell and the source cell use different TA adjustment amounts, the terminal device can perform GNSS measurements and then access the target cell.

In some embodiments, when a handover command instructs the target cell and source cell to use different TA adjustment values, the terminal device may stop the first timer in addition to performing GNSS measurements. For example, after receiving a RACH-less handover command (which instructs the target cell and source cell to use different TA adjustment values), the terminal device may stop the first timer, perform GNSS measurements, and then access the target cell.

The method embodiments of this application have been described in detail above with reference to Figures 1 to 7. The apparatus embodiments of this application will be described in detail below with reference to Figures 8 to 10. It should be understood that the descriptions of the method embodiments correspond to the descriptions of the apparatus embodiments. Therefore, any parts not described in detail can be referred to the foregoing method embodiments.

Figure 8 is a schematic diagram of the structure of a terminal device provided in an embodiment of this application. The terminal device 800 shown in Figure 8 includes an execution module 810.

The execution module 810 can be used to perform a first operation when a first random access procedure is triggered during the operation of a first timer, the first operation including one or more of the following: determining a valid GNSS location of the terminal device; determining the TA used in the first random access procedure based on the TA adjustment amount maintained before the first random access procedure; wherein, during the operation of the first timer, the terminal device is able to perform uplink transmission after the GNSS location fails.

Optionally, the effective GNSS position of the terminal device is determined based on one or more of the following methods: the terminal device considers the first timer to have expired and performs GNSS measurement when the first timer expires; the terminal device triggers RRC connection reconstruction and performs GNSS measurement before starting RRC connection reconstruction; the terminal device enters RRC idle state and performs GNSS measurement before the next RRC connection is established.

Optionally, performing GNSS measurement in the event of the first timer timeout includes: if autonomous GNSS measurement is configured, the terminal device autonomously initiates GNSS measurement; and/or if autonomous GNSS measurement is not configured, the terminal device enters an RRC idle state and performs GNSS measurement before the next RRC connection is established.

Optionally, the first random access procedure is triggered based on one or more of the following: scheduling request, cell handover.

Optionally, the first random access procedure is triggered based on cell handover, and the first operation includes: the terminal device triggering RRC connection reconstruction and performing GNSS measurements before starting RRC connection reconstruction.

Optionally, the TA adjustment amount is maintained by the terminal device based on the TA command sent by the network device.

Optionally, the first timer is a T390 timer.

Optionally, the terminal device is a terminal device connected to the NTN, and the terminal device is in an RRC connection state.

Optionally, the execution module 810 may be a processor 1010. The terminal device 800 may also include a memory 1020 and a transceiver 1030, as shown in FIG10.

Figure 9 is a schematic diagram of the structure of a terminal device provided in another embodiment of this application. The terminal device 900 shown in Figure 9 includes an operating module 910.

The operation module 910 can be used to continue running the first timer if the terminal device receives a RACH-less handover command sent by the network device during the operation of the first timer, and the handover command indicates that the target cell and the source cell use the same TA adjustment amount; wherein, during the operation of the first timer, the terminal device is able to perform uplink transmission after GNSS location failure.

Optionally, the terminal device further includes an execution module 920, configured to perform GNSS measurements and then access the target cell if the handover command instructs the target cell and the source cell to use different TA adjustment amounts.

Optionally, the terminal device further includes a stop module for stopping the first timer.

Optionally, the TA adjustment amount is maintained by the terminal device based on the TA command sent by the network device.

Optionally, the first timer is a T390 timer.

Optionally, the operating module 910 may be a processor 1010. The terminal device 900 may also include a memory 1020 and a transceiver 1030, as shown in Figure 10.

Figure 10 is a schematic structural diagram of a communication device according to an embodiment of this application. The dashed lines in Figure 10 indicate that the unit or module is optional. This device 1000 can be used to implement the methods described in the above method embodiments. The device 1000 can be a chip or a terminal device.

Apparatus 1000 may include one or more processors 1010. The processor 1010 may support apparatus 1000 in implementing the methods described in the preceding method embodiments. The processor 1010 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

The apparatus 1000 may further include one or more memories 1020. The memories 1020 store a program that can be executed by the processor 1010, causing the processor 1010 to perform the methods described in the preceding method embodiments. The memories 1020 may be independent of the processor 1010 or integrated within the processor 1010.

The device 1000 may also include a transceiver 1030. The processor 1010 can communicate with other devices or chips via the transceiver 1030. For example, the processor 1010 can send and receive data with other devices or chips via the transceiver 1030.

This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to a terminal device or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.

This application also provides a computer program product. The computer program product includes a program. This computer program product can be applied to a terminal device or network device provided in the embodiments of this application, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.

This application also provides a computer program. This computer program can be applied to the terminal device or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal device or network device in various embodiments of this application.

It should be understood that the terms "system" and "network" in this application can be used interchangeably. Furthermore, the terminology used in this application is only for explaining specific embodiments of the application and is not intended to limit the application. The terms "first," "second," "third," and "fourth," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. In addition, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

In the embodiments of this application, the term "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

In the embodiments of this application, "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and/or other information.

In the embodiments of this application, the term "correspondence" can indicate a direct or indirect correspondence between two things, or an association between two things, or a relationship such as instruction and being instructed, configuration and being configured.

In the embodiments of this application, the term "comprising" can refer to direct inclusion or indirect inclusion. Optionally, "comprising" in the embodiments of this application can be replaced with "instructing" or "used to determine". For example, "A includes B" can be replaced with "A instructs B" or "A is used to determine B".

In this application embodiment, "predefined" or "preconfigured" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and network devices). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

In this application embodiment, the "protocol" may refer to a standard protocol in the field of communication, such as the LTE protocol, the NR protocol, and related protocols applied to future communication systems. This application does not limit this.

In the embodiments of this application, the term "and/or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and/or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character "/" in this document generally indicates that the preceding and following related objects have an "or" relationship.

In the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is merely a logical function. In practice, there may be other ways to divide the system. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interface, device, or unit, and may be electrical, mechanical, or other forms.

The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can read or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims (32)

A method for wireless communication, characterized in that it includes: During the execution of the first timer, the terminal device performs a first operation when a first random access procedure is triggered, the first operation including one or more of the following: Determine the valid Global Navigation Satellite System (GNSS) position of the terminal device; The TA used in the first random access procedure is determined based on the timed advance TA adjustment amount maintained before the first random access procedure. During the operation of the first timer, the terminal device is able to perform uplink transmission after the GNSS location fails. According to the method of claim 1, the effective GNSS location of the terminal device is determined based on one or more of the following methods: The terminal device considers the first timer to have timed out and performs GNSS measurements if the first timer has timed out. The terminal device triggers Radio Resource Control (RRC) connection re-establishment and performs GNSS measurements before starting the RRC connection re-establishment. The terminal device enters the RRC idle state and performs GNSS measurements before the next RRC connection is established. The method according to claim 2, wherein performing GNSS measurements when the first timer times out includes: If autonomous GNSS measurement is configured, the terminal device autonomously initiates GNSS measurement; and/or If autonomous GNSS measurement is not configured, the terminal device enters the RRC idle state and performs GNSS measurement before the next RRC connection is established. The method according to any one of claims 1-3 is characterized in that the first random access procedure is triggered based on one or more of the following: scheduling request, cell handover. According to the method of claim 4, the first random access procedure is triggered based on cell handover, and the first operation includes: the terminal device triggering RRC connection reconstruction and performing GNSS measurements before starting RRC connection reconstruction. The method according to any one of claims 1-5 is characterized in that the TA adjustment amount is maintained by the terminal device according to the TA command sent by the network device. The method according to any one of claims 1-6 is characterized in that the first timer is a T390 timer. The method according to any one of claims 1-7 is characterized in that the terminal device is a terminal device accessing a non-terrestrial communication network (NTN), and the terminal device is in an RRC connection state. A method for wireless communication, characterized in that it includes: During the first timer operation, if the terminal device receives a RACH-less handover command sent by the network device, and the handover command indicates that the target cell and the source cell use the same timing advance TA adjustment amount, then the terminal device continues to run the first timer. During the operation of the first timer, the terminal device is able to perform uplink transmission after the GNSS position of the Global Navigation Satellite System fails. The method according to claim 9, characterized in that the method further comprises: If the handover command instructs the target cell and the source cell to use different TA adjustment values, the terminal device performs GNSS measurements and then accesses the target cell. The method according to claim 10, characterized in that the method further comprises: The terminal device stops the first timer. The method according to any one of claims 9-11 is characterized in that the TA adjustment amount is maintained by the terminal device according to the TA command sent by the network device. The method according to any one of claims 9-12 is characterized in that the first timer is a T390 timer. A terminal device, characterized in that it comprises: An execution module is configured to perform a first operation when a first random access procedure is triggered during the execution of a first timer, the first operation including one or more of the following: Determine the valid Global Navigation Satellite System (GNSS) position of the terminal device; The TA used in the first random access procedure is determined based on the timed advance TA adjustment amount maintained before the first random access procedure. During the operation of the first timer, the terminal device is able to perform uplink transmission after the GNSS location fails. The terminal device according to claim 14, wherein the effective GNSS location of the terminal device is determined based on one or more of the following methods: The terminal device considers the first timer to have timed out and performs GNSS measurements if the first timer has timed out. The terminal device triggers Radio Resource Control (RRC) connection re-establishment and performs GNSS measurements before starting the RRC connection re-establishment. The terminal device enters the RRC idle state and performs GNSS measurements before the next RRC connection is established. The terminal device according to claim 15, wherein performing GNSS measurement when the first timer times out includes: If autonomous GNSS measurement is configured, the terminal device autonomously initiates GNSS measurement; and/or If autonomous GNSS measurement is not configured, the terminal device enters the RRC idle state and performs GNSS measurement before the next RRC connection is established. The terminal device according to any one of claims 14-16 is characterized in that the first random access process is triggered based on one or more of the following: scheduling request, cell handover. The terminal device according to claim 17, wherein the first random access process is triggered based on cell handover, and the first operation includes: the terminal device triggering RRC connection reconstruction, and performing GNSS measurements before starting RRC connection reconstruction. The terminal device according to any one of claims 14-18 is characterized in that the TA adjustment amount is maintained by the terminal device according to the TA command sent by the network device. The terminal device according to any one of claims 14-19 is characterized in that the first timer is a T390 timer. The terminal device according to any one of claims 14-20 is characterized in that the terminal device is a terminal device accessing a non-terrestrial communication network (NTN), and the terminal device is in an RRC connection state. A terminal device, characterized in that it comprises: The operation module is configured to continue running the first timer if, during the operation of the first timer, the terminal device receives a RACH-less handover command sent by the network device, and the handover command instructs the target cell and the source cell to use the same timing advance TA adjustment amount; During the operation of the first timer, the terminal device is able to perform uplink transmission after the GNSS position of the Global Navigation Satellite System fails. The terminal device according to claim 22, wherein the terminal device further comprises: An execution module is configured to perform GNSS measurements and then access the target cell if the handover command instructs the target cell and the source cell to use different TA adjustment amounts. The terminal device according to claim 23, wherein the terminal device further comprises: The stop module is used to stop the first timer. The terminal device according to any one of claims 22-24 is characterized in that the TA adjustment amount is maintained by the terminal device according to the TA command sent by the network device. The terminal device according to any one of claims 22-25 is characterized in that the first timer is a T390 timer. A terminal device, characterized in that it includes a memory and a processor, the memory being used to store a program, and the processor being used to invoke the program in the memory to cause the terminal device to perform the method as described in any one of claims 1-13. An apparatus, characterized in that it includes a processor for calling a program from a memory to cause the apparatus to perform the method as described in any one of claims 1-13. A chip, characterized in that it includes a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1-13. A computer-readable storage medium, characterized in that it stores a program thereon, the program causing a computer to perform the method as described in any one of claims 1-13. A computer program product, characterized in that it includes a program that causes a computer to perform the method as described in any one of claims 1-13. A computer program, characterized in that the computer program causes a computer to perform the method as described in any one of claims 1-13.