ADJUSTMENT METHOD AND DETERMINATION METHOD FOR TRANSMISSION TIMING, AND TERMINAL DEVICE

TECHNICAL FIELD

The embodiments of the present disclosure relate to the field of communication, and more particularly, to an adjustment method and a determination method for transmission timing, and a terminal device.

BACKGROUND

In a New Radio-Non Terrestrial Network (NR-NTN) system, similar to a New Radio (NR) system, a User Equipment (UE) needs to consider impact of Timing Advance (TA) when performing uplink transmission. However, in the terrestrial communication system, a propagation delay of signal communication is usually less than 1 ms. In the NR-NTN system, due to a long communication distance between a terminal device and a satellite (or network device), the propagation delay of signal communication is very large, which may range from tens of milliseconds to hundreds of milliseconds, depending on the altitude of the satellite orbit and the traffic type of satellite communication. Based on this, in order to deal with a relatively large propagation delay, the scheme related to the transmission timing of the NR-NTN system needs to be enhanced compared with the NR system. In addition, since the position of the satellite changes in real time, the transmission timing adjustment method for the NR system is not suitable for the NTN system.

Therefore, it is desired that the present disclosure needs a transmission timing adjustment method for the NTN system.

SUMMARY

Embodiments of the present disclosure provide a transmission timing adjustment method, a transmission timing determination method, and a terminal device, which further improve the transmission timing adjustment method for the NTN system, such as an NR-NTN system or an Internet of Things (IoT)-NTN system.

In a first aspect, an embodiment of the present disclosure provides a transmission timing adjustment method, including:

acquiring first Timing Advance (TA) information, the first TA information being estimated by a terminal device; and

adjusting a first uplink TA value according to the first TA information to obtain a second uplink TA value.

In a second aspect, an embodiment of the present disclosure provides a transmission timing determination method, including:

determining an uplink TA value according to first TA information and/or second TA information,

wherein the first TA information is estimated by the terminal device, the second TA information is acquired through a Random Access Response (RAR) or a TA command transmitted by a network device, and the uplink TA value is used for transmitting a first physical channel or signal.

In a third aspect, an embodiment of the present disclosure provides a terminal device, which is configured to implement the method according to any one of the first aspect to the second aspect as described above or any implementation thereof. Particularly, it includes functional modules configured to perform the method in any possible implementation in the first aspect to the second aspect as described above.

In an implementation, the terminal device may include a processing unit configured to perform functions related to information processing. For example, the processing unit may be a processor.

In an implementation, the terminal device may include a transmitting unit and a receiving unit. The transmitting unit is configured to perform functions related to transmitting, and the receiving unit is configured to perform functions related to receiving. For example, the transmitting unit may be a transmitter, and the receiving unit may be a receiver. For another example, the terminal device may be a communication chip, the transmitting unit may be an input circuit or interface of the communication chip, and the receiving unit may be an output circuit or interface of the communication chip.

In a fourth aspect, an embodiment of the present disclosure provides a terminal device, which is configured to implement the method according to any one of the first aspect to the second aspect as described above or any implementation thereof. Particularly, it includes a processor, and a memory storing a computer program, wherein the processor is configured to invoke and execute the computer program stored in the memory, to cause the terminal device to perform the method according to any one of the first aspect to the second aspect as described above or any implementation thereof.

In an implementation, there may be one or more processors, and there may be one or more memories.

In an implementation, the memory may be integrated with the processor, or the memory may be provided separately from the processor.

In an implementation, the terminal device further includes a transmitter and a receiver.

In a fifth aspect, an embodiment of the present disclosure provides a system, wherein the system includes the terminal device as described above.

In a sixth aspect, an embodiment of the present disclosure provides a chip, which is configured to implement the method according to any one of the first aspect to the second aspect as described above or any implementation thereof. Particularly, the chip includes: a processor configured to invoke and execute the computer program from the memory, to cause a device equipped with the chip to perform the method according to any one of the first aspect to the second aspect as described above or any implementation thereof.

In a seventh aspect, an embodiment of the present disclosure provides a computer-readable storage medium, having a computer program stored thereon, the computer program causing a computer to perform the method according to any one of the first aspect to the second aspect as described above or any implementation thereof.

In an eighth aspect, an embodiment of the present disclosure provides a computer program product, including computer program instructions. The computer program instructions cause a computer to perform the method according to any one of the first aspect to the second aspect as described above or any implementation thereof.

In a ninth aspect, an embodiment of the present disclosure provides a computer program. The computer program, when executed by a computer, causes the computer to perform the method according to any one of the first aspect to the second aspect as described above or any implementation thereof.

Based on the above technical solutions, the first TA information is estimated by the terminal device, and the first uplink TA value is adjusted according to the first TA information to obtain the second uplink TA value. The terminal device is designed to have the capability of adjusting the TA by itself, or the terminal device needs the first TA information estimated by itself for uplink transmission, that is, the timing relationship between the downlink frame and the uplink frame of the terminal device is determined according to the first TA information estimated by the UE itself. Based on this, for the NTN system (e.g., the NR-NTN system or IoT-NTN system), when a position of a satellite changes, the second uplink TA value obtained by adjusting the first uplink TA value according to the first TA information is used for uplink transmission, which facilitates the terminal device to self-compensate the variation of the transmission timing caused by the variation of the position of the satellite, and improves the transmission timing adjustment method for the NTN system.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 to FIG. 3 are schematic block diagrams of system frameworks provided by embodiments of the present disclosure;

FIG. 4 and FIG. 5 respectively show schematic diagrams of NTN scenarios based on a transparent payload satellite and a regenerative payload satellite;

FIG. 6 is a schematic structural diagram of Case 1 in a timing relationship of an NTN system provided by an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of Case 2 in a timing relationship of an NTN system provided by an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a timing relationship between a downlink frame and an uplink frame of a terminal device in an NR system provided by an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of adjusting N_TAwhen a downlink reference timing changes in an NR system provided by an embodiment of the present disclosure;

FIG. 10 is a schematic flowchart of a transmission timing adjustment method provided by an embodiment of the present disclosure;

FIG. 11 is a schematic diagram of a timing relationship between a downlink frame and an uplink frame of a terminal device in an NTN system provided by an embodiment of the present disclosure;

FIG. 12 is a schematic diagram of overlapping of two adjacent time slots due to adjusting a first uplink TA value according to first TA information according to an embodiment of the present disclosure;

FIG. 13 is a schematic diagram of no overlapping of two adjacent time slots due to adjusting a first uplink TA value according to first TA information provided by an embodiment of the present disclosure;

FIG. 14 is a schematic comparison diagram before and after adjustment of a first uplink TA value by a terminal device according to first TA information according to an embodiment of the present disclosure;

FIG. 15 is an example of reducing a length of a later time slot among two adjacent time slots provided by an embodiment of the present disclosure;

FIG. 16 is an exemplary flowchart of a transmission timing determination method provided by an embodiment of the present disclosure;

FIG. 17 and FIG. 18 are schematic block diagrams of terminal devices according to embodiments of the present disclosure;

FIG. 19 is a schematic structural diagram of a communication device according to an embodiment of the present disclosure; and

FIG. 20 is a schematic structural diagram of a chip according to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Technical solutions according to the embodiments of the present disclosure will be described below in conjunction with accompanying drawings of the embodiments of the present disclosure.

FIG. 1 is a schematic block diagram of an application scenario of an embodiment of the present disclosure.

As shown in FIG. 1, a communication system 100 may include a terminal device 110 and a network device 120. The network device 120 may communicate with the terminal device 110 via an air interface. Multi-service transmission is supported between the terminal device 110 and the network device 120.

It should be understood that the embodiments of the present disclosure are only described by taking the communication system 100 as an example for illustration, but the embodiments of the present disclosure are not limited thereto. That is to say, the technical solutions of the embodiments of the present disclosure may be applied to various communication systems, e.g., a Long Term Evolution (LTE) system, an LTE Time Division Duplex (TDD), a Universal Mobile Communication System (UMTS), an Internet of Things (IoT) system, a Narrow Band Internet of Things (NB-IoT) system, an enhanced Machine-Type Communications (eMTC) system, a 5G communication system (also known as New Radio (NR) communication system), or future communication systems, etc.

In the communication system 100 as shown in FIG. 1, the network device 120 may be an access network device that communicates with the terminal device 110. The access network device may provide communication coverage for a specific geographic area, and may communicate with the terminal device(s) 110 (such as UE(s)) located in the coverage area.

The network device 120 may be an evolved base station (Evolutional Node B, eNB or eNodeB) in a Long Term Evolution (LTE) system, or a Next Generation Radio Access Network (NG RAN) device, either a base station (gNB) in the NR system, or a wireless controller in a Cloud Radio Access Network (CRAN), or the network device 120 may be a relay station, an access point, a vehicle-mounted device, a wearable device, a hub, a switch, a bridge, a router, or a network device in the future evolved Public Land Mobile Network (PLMN), etc.

The terminal device 110 may be any terminal device, including but not limited to, a terminal device connected to the network device 120 or other terminal devices by wire or wirelessly.

For example, the terminal device 110 may refer to an access terminal, a User Equipment (UE), a user unit, a user station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user apparatus. The access terminal may be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, an IoT device, a satellite handheld terminal, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device having a wireless communication function, a computing device or another processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5G network, or a terminal device in the future evolved PLMN, etc.

The terminal device 110 may be used for Device to Device (D2D) communication.

The wireless communication system 100 may also include a core network device 130 for communicating with a base station. The core network device 130 may be a 5G Core (5GC) device, for example, Access and Mobility Management Function (AMF), and for another example, Authentication Server Function (AUSF), and for another example, User Plane Function (UPF), and for another example, Session Management Function (SMF). Alternatively, the core network device 130 may also be an Evolved Packet Core (EPC) device of the LTE network, for example, a Session Management Function+Core Packet Gateway, (SMF+PGW-C) device. It should be understood that the SMF+PGW-C may implement functions of both SMF and PGW-C. In the process of network evolution, the above-mentioned core network device may be called by other names, or a new network entity may be formed by dividing functions of the core network, which is not limited in the embodiments of the present disclosure.

Various functional units in the communication system 100 may also communicate by establishing a connection via a Next Generation (NG) interface.

For example, the terminal device establishes an air interface connection with the access network device via an NR interface for transmitting user plane data and control plane signaling. The terminal device may establish a control plane signaling connection with the AMF via an NG interface 1 (N1 for short). The access network device, such as a Next Generation radio access base station (gNB), may establish a user plane data connection with the UPF via an NG interface 3 (N3 for short). The access network device may establish a control plane signaling connection with the AMF via an NG interface 2 (N2 for short). The UPF may establish a control plane signaling connection with the SMF via an NG interface 4 (N4 for short). The UPF may exchange user plane data with the data network via an NG interface 6 (N6 for short). The AMF establishes a control plane signaling connection with the SMF via an NG interface 11 (N11 for short). The SMF may establish a control plane signaling connection with the PCF via an NG interface 7 (N7 for short).

FIG. 1 schematically shows one base station, one core network device, and two terminal devices. Alternatively, the wireless communication system 100 may include a plurality of base station devices, and each base station may cover other numbers of terminals within its coverage, which is not limited in the embodiments of the present disclosure.

The 3^rdGeneration Partnership Project (3GPP) is studying Non-Terrestrial Network (NTN) technology. The NTN generally provides communication services to ground users by means of satellite communication. Compared with the terrestrial cellular network communication, the satellite communication has many unique advantages. First, the satellite communication is not restricted by the user's region. For example, the general land communication cannot cover areas such as oceans, mountains, deserts, etc. that cannot be equipped with communication devices or are not covered by communication due to sparse population. For the satellite communication, since one satellite may cover a larger area of the ground, and the satellite may orbit the earth, every corner of the earth may be covered by the satellite communication theoretically. Second, the satellite communication has a greater social value. The satellite communication may cover remote mountainous areas, poor and backward countries or regions at a lower cost, so that people in these regions may enjoy advanced voice communication and mobile Internet technology, which facilitates to narrow the digital gap with developed regions and promotes the development of these regions. Third, the distance of the satellite communication is longer, and the cost of communication does not increase significantly with the increase of the communication distance. Finally, the stability of the satellite communication is higher, which is not restricted by natural disasters.

The NTN technology may be combined with various communication systems. For example, the NTN technology may be combined with the NR system to form an NR-NTN system. For another example, the NTN technology may be combined with the IoT system to form an IoT-NTN system. As an example, the IoT-NTN system may include an NB-IoT-NTN system and an eMTC-NTN system.

FIG. 2 is a schematic diagram of an architecture of another communication system provided by an embodiment of the present disclosure.

As shown in FIG. 2, the communication system includes a terminal device 1101 and a satellite 1102, and the wireless communication may be performed between the terminal device 1101 and the satellite 1102. The network formed between the terminal device 1101 and the satellite 1102 may also be referred to as NTN. In the architecture of the communication system as shown in FIG. 2, the satellite 1102 may function as a base station, and direct communication may be performed between the terminal device 1101 and the satellite 1102. Under the system architecture, the satellite 1102 may be referred to as a network device. In some embodiments of the present disclosure, the communication system may include a plurality of network devices 1102, and each network device 1102 may cover other numbers of terminal devices within its coverage, which is not limited in the embodiment of the present disclosure.

FIG. 3 is a schematic diagram of an architecture of another communication system provided by an embodiment of the present disclosure.

As shown in FIG. 3, the communication system includes a terminal device 1201, a satellite 1202 and a base station 1203. The wireless communication may be performed between the terminal device 1201 and the satellite 1202, and the communication may be performed between the satellite 1202 and the base station 1203. The network formed among the terminal device 1201, the satellite 1202 and the base station 1203 may also be referred to as NTN. In the architecture of the communication system as shown in FIG. 3, the satellite 1202 may not function as a base station, and the communication between the terminal device 1201 and the base station 1203 needs to be relayed via the satellite 1202. Under the system architecture, the base station 1203 may be referred to as a network device. In some embodiments of the present disclosure, the communication system may include a plurality of network devices 1203, and each network device 1203 may cover other numbers of terminal devices within its coverage, which is not limited in the embodiments of the present disclosure. The network device 1203 may be the network device 120 in FIG. 1.

It should be understood that the aforementioned satellite 1102 or satellite 1202 includes but is not limited to:

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. The satellite may use a plurality of beams to cover the ground. For example, one satellite may form dozens or even hundreds of beams to cover the ground. In other words, one satellite beam may cover a ground area with a diameter of tens to hundreds of kilometers to ensure the coverage of the satellite and to improve the system capacity of the entire satellite communication system.

As an example, the altitude range of the LEO may be 500 km to 1500 km, the corresponding orbit period may be about 1.5 hours to 2 hours, the signal propagation delay of single-hop communication between users may generally be less than 20 ms, and the maximum satellite visible time may be 20 minutes. The signal propagation distance of the LEO is shorter and the link loss is smaller, and the requirements for the transmit power of the user terminal are not higher. The orbital height of the GEO may be 35786 km, the rotation period around the earth may be 24 hours, and the signal propagation delay of single-hop communication between the users may generally be 250 ms.

In order to ensure the coverage of the satellite and improve the system capacity of the entire satellite communication system, the satellite uses multi-beams to cover the ground. A satellite may form dozens or even hundreds of beams to cover the ground. One satellite beam may cover a ground area with a diameter of tens to hundreds of kilometers.

It should be noted that FIG. 1 to FIG. 3 are only illustrations of systems applicable to the present disclosure. Of course, the methods as shown in the embodiments of the present disclosure may also be applicable to other systems. Furthermore, the terms “system” and “network” are often used interchangeably herein. The term “and/or” herein just defines some association between associated objects, which means that there may be three relationships. For example, A and/or B may include three cases where there is only A, there are both A and B, and there is only B. In addition, the character “/” herein generally indicates that the contextual objects are in an “or” relationship. It should also be understood that “indicating” mentioned in the embodiments of the present disclosure may be a direct indication, or an indirect indication, and may also mean that there is some association therebetween. For example, A indicating B may mean that A directly indicates B, for example, B may be obtained from A; or may mean that A indirectly indicates B, for example, A indicates C, and B may be obtained from C; or may mean that there is some association between A and B. It should also be understood that “corresponding” mentioned in the embodiments of the present disclosure may mean that there is a direct correspondence or an indirect correspondence between the both, or that there is an association, or indicating and indicated, or configuring and configured, between the both. It should also be understood that “predefined” or “predefined rules” mentioned in the embodiments of the present disclosure may be implemented by saving corresponding codes or tables in the device (e.g., the terminal device or the network device) in advance or in other ways applicable to indicating related information, which is not particularly limited in the embodiments of the present disclosure. For example, “predefined” may refer to being defined in protocols. It should also be understood that in the embodiment of the present disclosure, “protocol” may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, an NR protocol, and related protocols applied to the future communication systems, which are not limited in the present disclosure.

The satellites may be classified into two categories of transparent payload and regenerative payload based on the functions they provide. The transparent payload satellite only provides functions of radio frequency filtering, frequency conversion and amplification, and only provides transparent forwarding of the signal without changing waveform signals it forwards. The regenerative payload satellite, in addition to providing the functions of radio frequency filtering, frequency conversion and amplification, it may also provide functions of demodulation/decoding, routing/conversion, coding/modulation, which have part or all of the functions of the base station.

In the NTN, one or more gateways (Gateway) may be included for communication between the satellites and the terminals.

FIG. 4 and FIG. 5 respectively show schematic diagrams of NTN scenarios based on a transparent payload satellite and a regenerative payload satellite.

As shown in FIG. 4, for the NTN scenario based on the transparent payload satellite, the communication between the gateway and the satellite is performed via a feeder link, and the communication between the satellite and the terminal may be performed via a service link. As shown in FIG. 5, for the NTN scenario based on the regenerative payload satellite, the communication between satellites is performed via an InterStar link, the communication between the gateway and the satellite is performed via the feeder link, and the communication between the satellite and the terminal is performed via the service link.

The timing relationship of the NTN system will be described below.

In the terrestrial communication system, the propagation delay of signal communication is generally less than 1 ms. In the NTN system, since the communication distance between the terminal device and the satellite (or the network device) is very long, the propagation delay of the signal communication is very large, ranging from tens of milliseconds to hundreds of milliseconds, particularly depending on the satellite orbital height and the traffic type of the satellite communication. In order to deal with a relatively large propagation delay, the timing relationship of the NTN system needs to be enhanced compared with the NR system.

In the NTN system, like the NR system, the UE needs to consider the impact of Timing Advance (TA) when performing uplink transmission. Since the propagation delay in the system is relatively large, the range of the TA value is also relatively large. When the UE is scheduled to perform uplink transmission in time slot n (or subframe n), the UE considers a round-trip propagation delay, and transmits in advance during the uplink transmission, so that the signal arrives at the network device side at an uplink time slot n (or subframe n) of the network device side. Particularly, the timing relationship in the NTN system may include two cases, i.e., Case 1 and Case 2.

FIG. 6 is a schematic structural diagram of Case 1 in a timing relationship of an NTN system provided by an embodiment of the present disclosure.

As shown in FIG. 6, for Case 1, the downlink subframe and the uplink subframe at the network device side are aligned. Correspondingly, in order to make the uplink transmission of the UE arrive at the network device side in alignment with the uplink subframe of the network device side, the UE needs to use a larger TA value. In some cases, the TA value corresponds to a timing offset value Koffset.

FIG. 7 is a schematic structural diagram of Case 2 in a timing relationship of an NTN system provided by an embodiment of the present disclosure.

As shown in FIG. 7, for Case 2, there is an offset value between the downlink subframe and the uplink subframe at the network device side. In this case, if the uplink transmission of the UE is to be aligned with the uplink subframe at the network device side when it arrives at the network device side, the UE only needs to use a smaller TA value. In some cases, the TA value corresponds to a timing offset value Koffset. In other cases, a Round-Trip Time (RTT) of the UE corresponds to a timing offset value Koffset.

In order to facilitate the understanding of the solutions provided by the present disclosure, the transmission timing adjustment method for the NR system will be described below.

In the NR system, a terminal device may be configured with one or more Timing Advance Groups (TAGs). A TAG refers to a group of serving cells configured by Radio Resource Control (RRC), and the same timing reference cell and the same TA value are used for the uplink configuration corresponding to the group of serving cells. If a TAG includes a MAC entity of a Special Cell (SpCell), it is considered as a Primary Timing Advance Group (PTAG); otherwise, it is considered as a Secondary Timing Advance Group (STAG). In a Dual Connectivity (DC) scenario, according to a Master Cell Group (MCG) or a Secondary Cell Group (SCG) associated with the MAC entity, the SpCell refers to a Primary Cell (PCell) in the MCG or a Primary Secondary Cell (PSCell) in the SCG. In other scenarios, the SpCell refers to PCell.

The network device may maintain uplink time alignment by configuring a high-level parameter, such as an alignment timer (timeAlignmentTimer), via RRC, and each TAG is configured with an alignment timer to control a time duration within which the MAC entity may consider that the uplink of the serving cell associated with the TAG is in time alignment. The terminal device may perform TA adjustment according to a Timing Advance Command (TAC) transmitted by the network device. When the terminal device receives a Timing alignment Command (TAC) Media Access Control (MAC) Control Element (CE), if N_TAcorresponding to the indicated TAG has been applied to the maintenance process, the TAC is applied to adjust the indicated TAG, and the alignment timer associated with the indicated TAG is started or restarted. The TAC MAC CE includes 2-bit TAG Identity (ID) indication information and 6-bit TAC indication information.

The timing adjustment process of the terminal device will be described as follows.

The terminal device is provided with a TA offset value N_{TA, offset}, which is determined according to a frequency domain range of a cell and a multiplexing mode of uplink transmission (for example, determined according to a network deployment frequency band and an LTE or NR coexistence situation).

During a random access procedure, the terminal device determines T_TAaccording to T_TA=N_{TA, offset}*Tc, and performs Msg1 or MsgA transmission according to the determined T_TA.

If the terminal device successfully receives a Random Access Response (RAR) transmitted by the network device, the RAR includes a TA command, and the TA command includes a T_Afor indication, and thus the terminal device may determine N_TAin a Timing Advance Group (TAG) based on the T_A, i.e., N_TA=T_A*16*64/2^μ, where T_A=0, 1, 2, . . . , 3846.

The determination of the N_TAvalue is related to the subcarrier spacing of the first uplink transmission of the terminal device after receiving the RAR.

The terminal device determines T_TAaccording to T_TA=(N_TA+N_{TA, offset})*Tc, and performs transmission of an uplink channel or signal (such as PUSCH scheduled by an RAR uplink grant, or PUSCH scheduled by a fallback RAR uplink grant, or PUCCH corresponding to a successful RAR and carrying HARQ-ACK information) according to the determined T_TA.

If the terminal device receives the Timing Advance Command (TAC) MAC CE, in which an indication of the TA command TA is included, the terminal device updates the N_TAaccording to the T_Avalue, that is, the current N_{TA_old}is adjusted to N_{TA_new}, N_{TA_new}=N_{TA_old}+(T_A−31)*16*64/2^μ, where T_A=0, 1, 2, . . . , 63.

The determination of the N_{TA_new}value is related to the subcarrier spacing. The subcarrier spacing may be a subcarrier spacing of the uplink active BWP; or if the terminal device is configured with a plurality of uplink active BWPs, the subcarrier spacing may be a largest one of the plurality of uplink active BWPs; or if the terminal device performs uplink active BWP switching between receiving the TA command and applying the corresponding TA adjustment, the subcarrier spacing may be a subcarrier spacing of a new uplink active BWP; or if the terminal device performs uplink active BWP switching after applying the corresponding TA adjustment, the terminal device assumes that an absolute TA adjustment value remains unchanged before and after the active BWP switching.

The terminal device determines T_TAaccording to T_TA=(N_TA+N_{TA, offset})*Tc, and performs, according to the determined T_TA, uplink channel or signal transmission (for example, other uplink transmissions than transmission of Msg1, MsgA, Physical Uplink Shared Channel (PUSCH) scheduled by the RAR uplink grant, PUSCH scheduled by the fallback RAR uplink grant, and Physical Uplink Control Channel (PUCCH) corresponding to the successful RAR and carrying Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) information).

μ represents subcarrier spacing configuration, and a subcarrier spacing corresponding to μ is 2^μ*15 kHz, and Tc represents a sampling time interval unit, where Tc=1/(480*1000*4096).

If the terminal device receives a TA command in the uplink time slot n, the terminal device shall perform uplink transmission by applying a corresponding TA adjustment from the uplink time slot n+k+1 on, and the uplink transmission does not include the PUSCH scheduled by the RAR uplink grant, the PUSCH scheduled by the fallback RAR uplink grant, and the PUCCH corresponding to the successful RAR and carrying the HARQ-ACK information.

FIG. 8 is a schematic diagram of a timing relationship between a downlink frame and an uplink frame of a terminal device in an NR system provided by an embodiment of the present disclosure.

As shown in FIG. 8, for the timing relationship between the downlink frame and the uplink frame of the terminal device, a time length in advance of the uplink frame transmission relative to the downlink frame reception is T_TA=(N_TA+N_{TA, offset})*Tc for the frame with the same number. In other words, in the timing adjustment process of the terminal device, the terminal device should ensure that both the timing accuracy of the initial transmission and the subsequent slow timing adjustment value meet certain indexes. As mentioned above, the N_{TA, offset}value is determined according to the frequency domain range of the cell and the multiplexing mode of the uplink transmission. The N_TAvalue is determined according to the received TA command value, and does not change until the next TA command value is received.

FIG. 9 is a schematic diagram of adjusting N_TAwhen a downlink reference timing changes in an NR system provided by an embodiment of the present disclosure.

As shown in FIG. 9, if the terminal device finds that the downlink reference timing changes and is not compensated, or is partially compensated by the uplink timing adjustment without a TA command, the terminal device adjusts the N_TAvalue accordingly. In other words, the adjustment process is that the N_TAvalue is adjusted from N_TA1to N_TA2.

If an overlap between two adjacent time slots occurs due to the TA adjustment performed according to the TA command, the length of the later time slot will be reduced relative to the earlier time slot.

In the NTN, such as New Radio-Non Terrestrial Network (NR-NTN), system, similar to the NR system, the User Equipment (UE) needs to consider the impact of Timing Advance (TA) for the uplink transmission. However, in the terrestrial communication system, the propagation delay of the signal communication is usually less than 1 ms. In the NTN system, due to the long communication distance between the terminal device and the satellite (or network device), the propagation delay of the signal communication is very large, which may range from tens of milliseconds to hundreds of milliseconds, depending on the altitude of the satellite orbit and the traffic type of satellite communication. Based on this, in order to deal with a relatively large propagation delay, the scheme related to the transmission timing of the NTN system needs to be enhanced compared with the NR system. In addition, since the position of the satellite changes in real time, the transmission timing adjustment method for the NR system is not suitable for the NTN system. Therefore, the embodiments of the present disclosure provide a transmission timing adjustment method, a transmission timing determination method, and a terminal device, which further improve the transmission timing adjustment method for the NTN system.

FIG. 10 is a schematic flowchart of a transmission timing adjustment method 200 provided by an embodiment of the present disclosure, which may be performed by a terminal device, e.g., the terminal devices as shown in FIG. 1 to FIG. 5.

As shown in FIG. 10, the method 200 may include part or all of the following:

S210 of acquiring first TA information, the first TA information being estimated by the terminal device; and

S220 of adjusting a first uplink TA value according to the first TA information to obtain a second uplink TA value.

In this embodiment, the first TA information is estimated by the terminal device, and the first uplink TA value is adjusted according to the first TA information to obtain the second uplink TA value. The terminal device is designed to have the capability of adjusting the TA by itself, or the terminal device needs the first TA information estimated by itself for uplink transmission, that is, the timing relationship between the downlink frame and the uplink frame of the terminal device is determined according to the first TA information estimated by the UE itself. Based on this, for the NTN system, when a position of a satellite changes, the second uplink TA value obtained by adjusting the first uplink TA value according to the first TA information is used for uplink transmission, which facilitates the terminal device to self-compensate the variation of the transmission timing caused by the variation of the position of the satellite, and improves the transmission timing adjustment method for the NTN system.

In an implementation, the first TA information is used to adjust the first uplink TA value or to obtain the second uplink TA value.

In an implementation, the terminal device transmits a first physical channel or signal according to the second uplink TA value.

In an implementation, the first TA information is acquired by the terminal device itself. The first TA information is acquired by the terminal device based on synchronization assistance information. Alternatively, the synchronization assistance information includes at least one of: timing information, frequency offset information, position information, and ephemeris information. Alternatively, the position information includes at least one of: a position of the terminal device, a position of a serving satellite, a position of a non-serving satellite, a position of a network device, and a reference point position. Alternatively, the ephemeris information includes at least one of: ephemeris information of a serving satellite and ephemeris information of a non-serving satellite. Alternatively, the timing information includes at least one of: a common TA value (such as a timing offset value between the network device and the reference point and/or a timing offset value between the network device and the satellite), a common TA variation value, and a timestamp. Alternatively, the frequency offset information includes at least one of: a Doppler frequency shift, a Doppler frequency shift variation, a moving speed of a serving satellite, and a moving speed of a non-serving satellite. Alternatively, the synchronization assistance information is transmitted by the network device via at least one of: a system message (for example, an NTN dedicated system message), an RRC configuration, a MAC CE, and DCI.

In an implementation, the first TA information is estimated by the terminal device based on at least one of: a speed of a satellite, a position of the satellite, ephemeris information, a timestamp, a position of the terminal device, and a Global Navigation Satellite System (GNSS).

The network device needs to transmit to the terminal device, the synchronization assistance information, e.g., at least one of ephemeris information, a moving speed of a satellite, a position of the satellite, a reference point position, a common timing offset value (such as a timing offset value between the network device and the reference point and/or a timing offset value between the network device and the satellite), a timestamp, etc., for the terminal device to complete time domain and/or frequency domain synchronization. Correspondingly, the terminal device needs to acquire the synchronization assistance information transmitted by the network device, and at the same time, to complete the corresponding time domain and/or frequency domain synchronization according to its own GNSS capability. The terminal device should obtain, based on its GNSS capability, information including at least one of: a position, a time reference, and a frequency reference of the terminal device. And based on the above information and the synchronization assistance information indicated by the network device (such as ephemeris information or timestamp of the serving satellite), the terminal device may calculate the timing and the frequency offset, and apply TA compensation or frequency offset adjustment in the idle state or inactive state.

As an example, the terminal device estimates a UE-specific TA in the following manner.

Approach 1, in which

the terminal device estimates the UE-specific TA based on the position acquired by the GNSS and the ephemeris information of a serving satellite indicated by the network device.

Approach 2, in which

the terminal device estimates the UE-specific TA based on the reference time acquired by the GNSS and the reference time indicated by the network device, such as the timestamp.

In some embodiments, if the terminal device is in an idle state or an inactive state. That is, before the terminal device initiates a random access procedure, the terminal device in the idle state or the inactive state may calculate T_TAaccording to the following approach, and transmit Msg1 or MsgA according to the determined T_TA:

T
_TA=(N_{TA,UE-specific}+N_TA,offset+N_TA,common)*T_c; or

T
_TA=(N_{TA,UE-specific}+N_TA,offset)*T_c+N_TA,common,

where N_{TA, UE-specific}may be a TA value estimated by the terminal device itself, that is, first TA information or a TA value determined based on the first TA information; N_{TA, offset}IS determined according to a network deployment frequency band and an LTE or NR coexistence situation (as an example, N_{TA, offset}may be broadcast by the network device, or a default value if the network device does not broadcast); N_{TA, common}includes a common timing offset value broadcast by the network device, for example, it may be obtained according to the second TA information, and a granularity or unit of N_{TA, common}is determined according to Tc; and Tc represents a sampling time interval unit, where Tc=1/(480*1000*4096).

In some embodiments, if the network device does not broadcast the second TA information, N_{TA, common}is a default value or N_{TA, common}is 0.

In some embodiments, the terminal device may calculate T_TAaccording to the following formula, and perform transmission of the uplink channel or signal (for example, PUSCH scheduled by the RAR uplink grant, PUSCH scheduled by the fallback RAR uplink grant, PUCCH corresponding to the successful RAR and carrying the HARQ-ACK information) according to the determined T_TA:

T
_TA=(N_TA+N_{TA,UE-specific}+N_TA,offset+N_TA,common)*Tc,

where N_{TA, UE-specific}may be a TA value estimated by the terminal device itself, that is, first TA information or a TA value determined based on the first TA information; N_TAmay be a TA value indicated by the network device via the RAR; N_{TA, common}includes a common timing offset value broadcast by the network device, for example, it may be obtained according to the second TA information; and a granularity or unit of N_{TA, common}is determined according to Tc; and Tc represents a sampling time interval unit, where Tc=1/(480*1000*4096).

In some embodiments, if the network device does not broadcast the second TA information, N_{TA, common}is a default value or N_{TA, common}is 0.

In some embodiments, the N_TAvalue indicated by the network device via the RAR is only a positive value or a non-negative value.

In some embodiments, the N_TAvalue indicated by the network device via the RAR may be a positive value or a negative value or 0.

In an implementation, for the PUSCH scheduled by the RAR uplink grant, the PUSCH scheduled by the fallback RAR uplink grant, the PUCCH corresponding to the successful RAR and carrying the HARQ-ACK information, or the MsgA PUSCH corresponding to the MsgA, the terminal device may carry N_{TA, UE-specific}related indication information in the transmission process of the above channels.

In some embodiments, if the terminal device is in the connected state, T_TAmay be calculated according to the following formula, and uplink channel or signal transmission (for example, other uplink transmissions than transmission of Msg1, MsgA, PUSCH scheduled by the RAR uplink grant, PUSCH scheduled by the fallback RAR uplink grant, and PUCCH corresponding to the successful RAR and carrying HARQ-ACK information) may be performed according to the determined T_TA:

T
_TA=(N_TA+N_{TA,UE-specific}+N_TA,offset+N_TA,common)*Tc,

where N_{TA, UE-specific}may be a TA value estimated by the terminal device itself, that is, first TA information or a TA value determined based on the first TA information; N_{TA, offset}is determined according to a network deployment frequency band and an LTE or NR coexistence situation (as an example, N_{TA, offset}may be broadcast by the network device, or a default value if the network device does not broadcast); N_{TA, common}includes a common timing offset value broadcast by the network device, for example, it may be obtained according to the second TA information, and a granularity or unit of N_{TA, common}is determined according to Tc; Tc represents a sampling time interval unit, where Tc=1/(480*1000*4096); and N_TAmay be a TA value indicated by the network device, for example, may be a TA value indicated in the TA command.

In some embodiments, if the network device does not broadcast the second TA information, N_{TA, common}is a default value or N_{TA, common}is 0.

In some embodiments, the N_TAvalue indicated by the network device via the TA command MAC CE is only a positive value or a non-negative value.

In some embodiments, the N_TAvalue indicated by the network device via the TA command MAC CE may be a positive value or a negative value or 0.

In an implementation, the terminal device may transmit N_{TA, UE-specific}related indication information to the network device via the uplink MAC CE.

In other words, for NTN, the terminal device needs to jointly estimate and update the TA according to the TA value estimated by the terminal device itself, the common timing offset value broadcast by the network device, and the TA value indicated by the network device.

In other words, for the terminal device in the NTN system, the terminal device is required to have the capability of performing TA adjustment using the GNSS module. In other words, the terminal device needs to perform the uplink transmission according to the TA value estimated by the terminal device itself. That is to say, the timing relationship between the downlink frame and the uplink frame of the terminal device is determined according to the TA value estimated by the UE itself.

FIG. 11 is a schematic diagram of a timing relationship between a downlink frame and an uplink frame of a terminal device in an NTN system provided by an embodiment of the present disclosure.

As shown in FIG. 11, for frames with the same number, the time length in advance of the uplink frame transmission relative to the downlink frame reception is T_TA=(N_TA+N_{TA, UE-specific}+N_{TA, offset}+N_{TA, common})*Tc. In this case, the UE may perform TA adjustment according to the TA value estimated by the UE itself.

In some embodiments, the first TA information includes at least one of a first TA value and first TA variation information.

In an implementation, the first TA variation information is used to measure variation of the first TA value within a unit of time, where the unit of time may be millisecond, second, time slot, etc., which is not limited by the present disclosure. For example, the first TA variation information is a TA offset (drift) of the first TA value.

In an implementation, the first TA variation information may include TA variation information of a serving link of the terminal device.

In some embodiments, if two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information, the terminal device does not expect to adjust the first uplink TA value according to the first TA information; or if the two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information, and a length of an overlapping portion is greater than or equal to a first threshold, the terminal device does not expect to adjust the first uplink TA value according to the first TA information.

In an implementation, the first threshold is determined according to a length of a Cyclic Prefix (CP).

In an implementation, the first threshold is a length of the CP or half of the length.

It should be noted that, in the embodiments of the present disclosure, “if . . . ” in the embodiments of the present disclosure may be interpreted as “if” or “when . . . ”, “in a case of . . . ”, “in a case where . . . ”, “when determining . . . ”, “in response to . . . ” or “in response that . . . ”. Similarly, depending on the context, the phrases “if . . . , then the terminal device does not expect to adjust . . . ” or “if . . . , then the terminal device adjusts . . . ” may be interpreted as “when it is determined that . . . , the terminal device does not perform an adjustment operation” or “when it is determined that . . . , the terminal device performs an adjustment operation”. It should be understood that the term “if” as mentioned below may also be interpreted according to the above explanation, and will not be repeated in order to avoid repetition.

As shown in FIG. 12, if the terminal device is scheduled to perform uplink transmission from time slots n−2 to n+1, if an overlap between two adjacent time slots occurs after the first uplink TA value is adjusted according to the first TA information, the terminal device does not adjust the first uplink TA value according to the first TA information during the uplink transmission.

In some embodiments, if adjusting the first uplink TA value according to the first TA information leads to no overlapping of two adjacent time slots, the terminal device adjusts the first uplink TA value according to the first TA information; or if the two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information, and a length of an overlapping portion is smaller than or equal to a first threshold, the terminal device adjusts the first uplink TA value according to the first TA information.

In an implementation, the first threshold value is determined according to the length of a Cyclic Prefix (CP).

In an implementation, the first threshold is a length of the CP or half of the length.

FIG. 13 is a schematic diagram of no overlapping due to adjusting a first uplink TA value according to first TA information provided by an embodiment of the present disclosure.

As shown in FIG. 13, if the terminal device is scheduled to perform uplink transmission from time slots n−2 to n+1, if no overlap between two adjacent time slots occurs after the first uplink TA value is adjusted according to the first TA information, the terminal device adjusts the first uplink TA value according to the first TA information during the uplink transmission.

In some embodiments, the method 200 may further include:

determining whether to adjust the first uplink TA value according to the first TA information, based on an overlapping status of the two adjacent time slots due to adjusting the first uplink TA value according to the first TA information.

In other words, the overlapping status of the two adjacent time slots due to adjusting the first uplink TA value according to the first TA information may be used as a decision status for the terminal device to decide whether to adjust the first uplink TA value according to the first TA information or not.

In some embodiments, the terminal device does not expect to adjust the first uplink TA value according to the first TA information during uplink transmission.

In an implementation, the uplink transmission includes scheduled continuous uplink transmissions of the terminal device.

In an implementation, the terminal device is scheduled to perform continuous uplink transmissions from time slots n−2 to n+1, and the terminal device does not expect to perform TA adjustment according to the first TA value obtained by itself.

In some embodiments, the terminal device does not expect a length of the scheduled continuous uplink transmissions to be greater than or equal to a second threshold; or the terminal device allows the length of the scheduled continuous uplink transmissions to be smaller than or equal to the second threshold.

In an implementation, the second threshold value is determined based on a frequency or a period at which the terminal device adjusts the first uplink TA value. As an example, the second threshold value is determined based on the frequency or period at which the terminal device adjusts the first uplink TA value by itself. For example, the second threshold value is determined based on the frequency or period at which the terminal device adjusts the first uplink TA value according to the first TA information.

In an implementation, if the terminal device needs to estimate the first uplink TA value by itself every 10 ms, the terminal device does not expect the length of the scheduled continuous uplink transmissions to be greater than or equal to 10 ms; or, the terminal device allows the length of the scheduled continuous uplink transmissions smaller than or equal to 10 ms.

In an implementation, if a downlink reference timing of the terminal device changes and is not compensated, or if the downlink reference timing of the terminal device changes and is partially compensated without receiving a TA command,

the terminal device adjusts the first TA information; or

the terminal device adjusts the first uplink TA value according to the first TA information; or

the terminal device adjusts the second uplink TA value according to the first TA information.

In an implementation, the terminal device compensates for an uncompensated portion by adjusting the first TA information.

In an implementation, the second TA information is acquired through a Random Access Response (RAR) or a TA command transmitted by the network device.

In an implementation, the second TA information includes at least one of a second TA value and second TA variation information.

In an implementation, the second TA variation information is used to measure variation of the second TA value within a unit of time, where the unit of time may be millisecond, second, time slot, etc., which is not limited by the present disclosure. For example, the second TA variation information is a TA offset (drift) of the second TA value.

In an implementation, the second TA variation information may include TA variation information of a feeder link of the terminal device.

As shown in FIG. 14, the terminal device adjusts the first uplink TA value according to the first TA information. If the terminal device is in a connected state, T_TAmay be calculated according to the following formula, and the uplink channel or signal transmission may be performed according to the determined T_TA:

T
_TA=(N_TA+N_{TA,UE-specific}+N_TA,offset+N_TA,common)*Tc,

where N_{TA, UE-specific}may be a TA value estimated by the terminal device itself, i.e., first TA information or a TA value determined based on the first TA information.

Based on this, the terminal device adjusts the first uplink TA value according to the first TA information. Before the terminal device adjusts the first uplink TA value according to the first TA information, N_{TA, UE-specific}is N_{TA, UE-specific,1}, thus T_TA=(N_TA+N_{TA, UE-specific,1}+N_{TA, offset}+N_{TA, common})*Tc; when the adjusted N_{TA, UE-specific}is N_{TA, UE-specific,2}, T_TA=(N_TA+N_{TA, UE-specific,2}+N_{TA, offset}+N_{TA, common})*Tc; and when the adjusted N_{TA, UE-specific}is N_{TA, UE-specific,3}, T_TA=(N_TA+N_{TA, UE-specific,3}+N_{TA, offset}+N_{TA, common})*Tc.

In some embodiments, if the terminal device does not receive TA indication information transmitted by a network device or does not acquire second TA information, the terminal device adjusts the first uplink TA value according to the first TA information.

In an implementation, the behaviors of the terminal device may include: adjusting the first uplink TA value according to the self-estimated TA value and the TA value transmitted by the network device to obtain the second uplink TA value; or adjusting the first uplink TA value according to the self-estimated TA value to obtain the second uplink TA value.

In an implementation, the TA indication information transmitted by the network device is used to indicate the second TA information.

In some embodiments, if the two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information,

a length of an earlier one of the two adjacent time slots is reduced; or

a length of a later one of the two adjacent time slots is reduced; or

a length of each time slot of the two adjacent time slots that is not used for transmission is reduced.

In an implementation, the reduced length is equal to the length of the overlapping portion of the two adjacent time slots.

In an implementation, if the two adjacent time slots are both used for uplink transmission, or if the two adjacent time slots are both not used for uplink transmission, a predefined rule is required to be used. For example, if the two adjacent time slots are both used for uplink transmission, the terminal device does not expect to use the first TA information to adjust the first uplink TA value; if the two adjacent time slots are both not used for uplink transmission, the latter time slot of the two adjacent time slots is reduced.

FIG. 15 is an example of reducing a length of a later time slot among two adjacent time slots provided by an embodiment of the present disclosure.

As shown in FIG. 15, if the terminal device is scheduled to perform uplink transmission from time slots n−2 to n+1, if an overlap between two adjacent time slots (n−1 and n) occurs after the first uplink TA value is adjusted according to the first TA information, the terminal device reduces the length of the later time slot (i.e., time slot n) of the two adjacent time slots.

In some embodiments, the method 200 may further include:

performing uplink transmission by applying the second uplink TA value in an uplink time unit n+m+1, where n represents an uplink time unit for acquiring or estimating the first TA information, and m is a number greater than or equal to 0.

In an implementation, m is predefined or determined according to a predefined rule; or m is determined according to the capability of the terminal device; or m is determined according to a configuration parameter of the network device. As an example, the terminal device reports capability information of the terminal device, and accordingly, the network device configures a parameter for the terminal device based on the capability information reported by the terminal device.

In an implementation, the uplink time unit includes, but is not limited to, a time slot, a subframe, a symbol, or a resource unit etc.

In some embodiments, the method 200 may further include:

determining the uplink time unit in which the second uplink TA value is applied for uplink transmission, based on the overlapping status of the two adjacent time slots due to adjusting the first uplink TA value according to the first TA information.

In an implementation, if the two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information, the terminal device performs unlink transmission by applying the second uplink TA value after the ongoing uplink transmission ends; or if adjusting the first uplink TA value according to the first TA information leads to no overlapping of two adjacent time slots, the terminal device performs uplink transmission by applying the second uplink TA value in the uplink time unit n+m+1, where n represents an uplink time unit for acquiring or estimating the first TA information, and m is a number greater than or equal to 0.

In an implementation, the uplink time unit includes, but is not limited to, a time slot, a subframe, a symbol, or a resource unit etc.

In some embodiments, the two adjacent time slots include a first time slot and a second time slot, and the first time slot is a first time slot in which the second uplink TA value is applied, and the second time slot is an adjacent time slot before the first time slot.

In some embodiments, S210 may include:

acquiring the first TA information according to a first subcarrier spacing.

In an implementation, the first subcarrier spacing is a subcarrier spacing of an uplink active Bandwidth Part (BWP); or the terminal device is configured with a plurality of uplink active BWPs, and the first subcarrier spacing is a largest one of the plurality of uplink active BWPs; or the terminal device performs uplink active BWP switching between acquiring the first TA information and performing uplink transmission by applying the second uplink TA value, and the first subcarrier spacing is a subcarrier spacing of a new uplink active BWP; or the terminal device performs uplink active BWP switching after performing uplink transmission by applying the second uplink TA value, and an absolute value of the second uplink TA value remains unchanged before switching the active BWP and after switching the active BWP.

In an implementation, the terminal device performs uplink active BWP switching after performing uplink transmission by applying the second uplink TA value, and an absolute value of the first uplink TA value remains unchanged before switching the active BWP and after switching the active BWP, or both the absolute value of the first uplink TA value and the absolute value of the second uplink TA value remain unchanged before switching the active BWP and after switching the active BWP.

In some embodiments, an error of the second uplink TA value satisfies a precision index.

In an implementation, in the process of the terminal device adjusting the first uplink TA value according to the first TA information, the terminal device ensures that the accuracy of the transmission timing of the initial transmission and the accuracy of the transmission timing of the subsequent slow transmission meet certain indexes.

In some embodiments, S210 may include:

estimating the first TA information within a time unit that is configured by a network or is predefined.

In the NTN system, with the solutions in the present disclosure, when the terminal device adjusts the first uplink TA value according to the self-estimated first TA information such as the first TA value and the position of the satellite changes, it is beneficial for the terminal device to self-compensate the variation of transmission timing caused by the variation of the position of the satellite, which improves the transmission timing adjustment method for the NTN system.

FIG. 16 is an exemplary flowchart of a transmission timing determination method 300 provided by an embodiment of the present disclosure, which may be performed by a terminal device, e.g., the terminal devices as shown in FIG. 1 to FIG. 5.

As shown in FIG. 16, the method 300 may include part or all of the following:

S310 of determining an uplink TA value according to first TA information and/or second TA information.

The first TA information is estimated by the terminal device, the second TA information is acquired through a Random Access Response (RAR) or a TA command transmitted by a network device, and the uplink TA value is used for transmitting a first physical channel or signal.

In some embodiments, the first TA information includes at least one of a first TA value and first TA variation information.

In some embodiments, the second TA information includes at least one of a second TA value and second TA variation information.

In some embodiments, S310 may include:

determining the uplink TA value according to N_{TA, UE-specific}, where N_{TA, UE-specific}is adjusted according to a formula as follows:

N
_{TA,UE-specific,new}
=N
_{TA,UE-specific,old}
+ΔN
_{TA,UE-specific},

where N_{TA, UE-specific, old}and/or ΔN_{TA,UE-specific}are obtained according to the first TA information.

In an implementation, ΔN_{TA,UE-specific}is obtained according to first TA variation information in the first TA information.

In some embodiments, S310 may include:

determining the uplink TA value according to N_{TA, common}, where N_{TA, common}is adjusted according to a formula as follows:

N
_{TA,common,new}
=N
_{TA,common,old}
+ΔN
_TA,common,

where ΔN_{TA, common}is obtained according to the second TA information.

In an implementation, ΔN_{TA, common}is obtained according to second TA variation information in the second TA information.

In an implementation, N_TA,commonmay include a TA value of a feeder link of the terminal device; or include a TA value of a link between the network device and the satellite; or include a TA value of a link between the network device and the reference point; or include a TA value of a link between the reference point and the satellite.

In some embodiments, S310 may include:

determining the uplink TA value according to N_{TA, UE-specific}, N_TAand N_{TA, common}, where N_{TA, UE-specific}is obtained according to the first TA information, N_TAis obtained according to the second TA information, and N_{TA, common}is obtained according to common TA information broadcast by the network device.

In an implementation, the uplink TA value is determined according to N_{TA, UE-specific}, N_TAand N_{TA, common}based on the following formula:

T
_TA=(N_{TA,UE-specific}+N_TA+N_TA,offset+N_TA,common)*Tc,

where T_TArepresents the uplink TA value, N_{TA, offset}is determined according to a frequency domain range of a cell and a multiplexing mode of the uplink transmission, and Tc represents a sampling time interval unit.

In an implementation, each term in the above formula may be updated independently.

For example, N_{TA, UE-specific}is updated according to the time unit of the self-estimated TA.

For another example, N_TAis updated after receiving the indication information of the network device.

In an implementation, N_{TA, offset}may also be broadcast by the network device. N_{TA, offset}may be a default value if the network device does not broadcast.

In some embodiments, the second TA information is acquired through the RAR transmitted by the network device, and the first physical channel or signal includes at least one of: a Physical Uplink Shared Channel (PUSCH) scheduled by an RAR uplink grant, a PUSCH scheduled by a fallback RAR uplink grant, and a Physical Uplink Control Channel (PUCCH) corresponding to a successful RAR and carrying Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) information.

In an implementation, the terminal device is in an idle state or an inactive state.

In some embodiments, the second TA information is acquired through the TA command transmitted by the network device, and the first physical channel or signal includes an uplink physical channel or signal except Message 1 (Msg1), Message A (MsgA), the PUSCH scheduled by the RAR uplink grant, the PUSCH scheduled by the fallback RAR uplink grant, and the PUCCH corresponding to the successful RAR and carrying the HARQ-ACK information.

In an implementation, the TA command is carried by a Media Access Control Control Element (MAC CE) or Downlink Control Information (DCI).

In an implementation, the terminal device is in a connected state.

In some embodiments, the first TA information being estimated by the terminal device includes: the first TA information being estimated by the terminal device based on at least one of: a velocity of a satellite, a position of a satellite, ephemeris information, a timestamp, a position of a terminal device, and Global Navigation Satellite System (GNSS).

The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications may be made to the technical solutions of the present disclosure. These simple modifications all belong to the protection scope of the present disclosure. For example, various specific technical features described in the above specific implementations may be combined in any suitable manner if there is no contradiction. In order to avoid unnecessary repetition, the present disclosure no longer describes the various possible combinations. As another example, any combination of various implementations of the present disclosure may also be made, as long as they do not violate the idea of the present disclosure, which should also be regarded as the content disclosed in the present disclosure.

It should also be understood that in the various method embodiments of the present disclosure, the sequence numbers of the above-mentioned processes do not mean the order of execution that should be determined by their functions and internal logic, and should not be used to limit the implementations of the present disclosure. In addition, in the embodiments of the present disclosure, the terms “downlink (DL)” and “uplink (UL)” are used to indicate the transmission direction of signals or data, “downlink (DL)” is used to indicate that the transmission direction of signals or data is a first direction from the station to the user equipment in the cell, and “uplink (UL)” is used to indicate that the transmission direction of signals or data is a second direction from the user equipment in the cell to the station. For example, “downlink signal” indicates that the signal transmission direction is the first direction. In addition, in the embodiments of the present disclosure, the term “and/or” herein just defines some association between associated objects, which means that there may be three relationships. For example, A and/or B may include three cases where there is only A, there are both A and B, and there is only B. In addition, the character “/” herein generally indicates that the contextual objects are in an “or” relationship.

The method embodiments of the present disclosure are described above in detail in conjunction with FIG. 1 to FIG. 16. Hereinafter, the device embodiments of the present disclosure will be described in detail in conjunction with FIG. 17 to FIG. 20.

FIG. 17 is a schematic block diagram of a terminal device 400 according to an embodiment of the present disclosure.

As shown in FIG. 17, the terminal device 400 may include:

a communication unit 410 configured to acquire first TA information, the first TA information being estimated by a terminal device; and

a processing unit 420 configured to adjust a first uplink TA value according to the first TA information to obtain a second uplink TA value.

In some embodiments, the first TA information includes at least one of a first TA value and first TA variation information.

In some embodiments, if two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information, the terminal device does not expect to adjust the first uplink TA value according to the first TA information; or if the two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information and a length of an overlapping portion is greater than or equal to a first threshold, the terminal device does not expect to adjust the first uplink TA value according to the first TA information.

In some embodiments, if adjusting the first uplink TA value according to the first TA information leads to no overlapping of two adjacent time slots, the terminal device adjusts the first uplink TA value according to the first TA information; or if the two adjacent time slots overlap due to adjusting the first uplink TA value according to the first TA information and a length of an overlapping portion is smaller than or equal to a first threshold, the terminal device adjusts the first uplink TA value according to the first TA information.

In an implementation, the first threshold value is determined according to a length of a cyclic prefix (CP).

In an implementation, the first threshold is a length of a CP or half of the length.

In some embodiments, the processing unit 420 is further configured to determine whether to adjust the first uplink TA value according to the first TA information, based on an overlapping status of the two adjacent time slots due to adjusting the first uplink TA value according to the first TA information.

In some embodiments, the terminal device does not expect to adjust the first uplink TA value according to the first TA information during uplink transmission.

In an implementation, the uplink transmission includes scheduled continuous uplink transmissions of the terminal device.

In some embodiments, the terminal device does not expect a length of the scheduled continuous uplink transmissions to be greater than or equal to the second threshold; or the terminal device allows the length of the scheduled continuous uplink transmissions to be smaller than or equal to the second threshold.

In an implementation, the second threshold value is determined based on a frequency or a period at which the terminal device adjusts the first uplink TA value.

In some embodiments, if a downlink reference timing of the terminal device changes and is not compensated, or if the downlink reference timing of the terminal device changes and is partially compensated without receiving a TA command,