Communication method and device

Abstract

The invention provides a communication method and device. The method comprises: a terminal device receiving first information sent by a first base station, the first information comprising a first timing advance of a second base station, or the first information comprising a parameter for the terminal device to obtain the first timing advance of the second base station, the first time advance is a time advance used in a data transmission process with the second base station; and the terminal equipment acquires the first time advance of the second base station through the first information. According to the method provided by the invention, the terminal equipment can acquire the time advance of the next base station in advance when facing a timing advance TA jump problem caused by base station switching in a non-ground communication NTN scene.

Description

[0001] This application is a divisional application. The application number of the original application is 202010274562.0, and the original application date is April 9, 2020. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of communications, and more specifically, to a communication method and device. Background Art

[0003] In long term evolution (LTE) or new radio (NR) communication technology, different terminal equipment (UE) uses orthogonal multiple access in time and frequency during uplink transmission, that is, the uplink transmissions of different UEs from the same cell do not interfere with each other. In order to ensure the orthogonality of uplink transmission and avoid intra-cell interference, the time when signals from different UEs in the same subframe but different frequency domain resources (different resource blocks RB) arrive at the base station is basically aligned. In order to ensure time synchronization on the receiving side (base station side), long term evolution (LTE) / new radio (NR) adopts an uplink timing advance mechanism.

[0004] In order to adapt to non-terrestrial communication (NTN), such as satellite communication, the prior art proposes that a satellite broadcast common timing advance (common TA) can be used to ensure time synchronization on the receiving side. However, the common TA mechanism in the prior art only involves the broadcast of the common TA of the cell, and does not take into account the problem of TA change during satellite switching in the NTN scenario. Summary of the invention

[0005] The present application provides a communication method, which enables a terminal device to obtain the time advance of the next base station in advance when facing a TA jump problem caused by base station switching in an NTN scenario.

[0006] In a first aspect, a communication method is provided, the method comprising: a terminal device receives first information sent by a first base station, the first information includes a first timing advance of a second base station, or the first information includes a parameter for the terminal device to obtain the first timing advance of the second base station, and the first timing advance is a timing advance used during data transmission with the second base station; the terminal device obtains the first timing advance of the second base station through the first information.

[0007] The method provided in the present application enables the terminal device to obtain the time advance of the next base station in advance when facing the TA hopping problem caused by base station switching in the NTN scenario.

[0008] In combination with the first aspect, in some implementations of the first aspect, the first information also includes: switching information between the first base station and the second base station, and the switching information includes the switching location and / or the switching time between the first base station and the second base station.

[0009] In combination with the first aspect, in some implementations of the first aspect, the terminal device communicates with the second base station according to the first timing advance of the second base station and the switching information between the first base station and the second base station.

[0010] By communicating with the second base station according to the first time advance and the switching information between the first base station and the second base station, seamless switching between the terminal device and the second base station after switching can be achieved, avoiding service interruption caused by base station handover or signaling storm caused by switching.

[0011] In combination with the first aspect, in certain implementations of the first aspect, the first information includes parameters for the terminal device to obtain the first time advance of the second base station, and the parameters include at least one of the following: the time advance of the first base station, the location of the terminal device, the location of the first base station, or the location of the second base station; obtaining the first time advance of the second base station through the first information includes: the terminal device calculates the first time advance of the second base station according to the parameters.

[0012] In combination with the first aspect, in certain implementations of the first aspect, the first information includes parameters for the terminal device to obtain the first time advance of the second base station, and the parameters include: the second time advance of the second base station, and the second time advance of the second base station is the time advance used in the access process with the second base station; obtaining the first time advance of the second base station through the first information includes: the terminal device initiating an access process to the second base station according to the second time advance of the second base station, and obtaining the first time advance of the second base station during the access process.

[0013] In a second aspect, a communication method is provided, the method comprising: a first base station generates first information, the first information comprising a first timing advance of a second base station, or the first information comprises a first timing advance parameter for the terminal device to obtain the second base station, the first timing advance is the timing advance used during data transmission between the terminal device and the second base station; the first base station sends the first information to the terminal device.

[0014] When facing the TA hopping problem caused by base station switching in the NTN scenario, the terminal device can obtain the time advance of the next base station in advance according to the first information.

[0015] In combination with the second aspect, in some implementations of the second aspect, the first information also includes: switching information between the first base station and the second base station, and the switching information includes the switching location and / or switching time between the first base station and the second base station.

[0016] By adding the switching information of the first base station and the second base station to the first information, the terminal device can further achieve seamless switching between different base stations when switching satellites in the NTN scenario, avoiding service interruption caused by base station handover or signaling storm caused by switching.

[0017] In combination with the second aspect, in certain implementations of the second aspect, the first information includes parameters for the terminal to obtain a first timing advance of the second base station, and the parameters include at least one of the following: the timing advance of the first base station, the location of the terminal device, and the location of the first base station or the second base station.

[0018] In combination with the second aspect, in certain implementations of the second aspect, the first information includes parameters for the terminal to obtain the first time advance of the second base station, and the parameters include: the second time advance of the second base station, and the second time advance of the second base station is the time advance used by the terminal device during the access process with the second base station.

[0019] In combination with the second aspect, in some implementations of the second aspect, the first information is sent by the first base station through broadcasting.

[0020] In combination with the second aspect, in some implementations of the second aspect, the first information is sent by the second base station to the first base station; and the method also includes: receiving the first indication information sent by the second base station.

[0021] According to a third aspect, a communication device is provided, comprising: a receiving module for receiving first information sent by a first base station, the first information comprising a first timing advance of a second base station, or the first information comprising a parameter for the communication device to obtain the first timing advance of the second base station, the first timing advance being the timing advance used during data transmission with the second base station; and a processing module for obtaining the first timing advance of the second base station through the first information.

[0022] The method provided in the present application enables a communication device to obtain the timing advance of the next base station in advance when facing a TA jump problem caused by base station switching in an NTN scenario.

[0023] In combination with the third aspect, in certain implementations of the third aspect, the first information also includes: switching information between the first base station and the second base station, and the switching information includes the switching location and / or switching time between the first base station and the second base station.

[0024] In combination with the third aspect, in some implementations of the third aspect, the device also includes: a communication module, used to communicate with the second base station according to the first timing advance of the second base station and the switching information between the first base station and the second base station.

[0025] By communicating with the second base station according to the first time advance and the switching information between the first base station and the second base station, seamless switching between the terminal device and the second base station after switching can be achieved, avoiding service interruption caused by base station handover or signaling storm caused by switching.

[0026] In combination with the third aspect, in certain implementations of the third aspect, the first information includes parameters used by the communication device to obtain the first time advance of the second base station, and the parameters include at least one of the following: the time advance of the first base station, the location of the communication device, the location of the first base station, or the location of the second base station; the processing module is used to: calculate the first time advance of the second base station based on the parameters.

[0027] In combination with the third aspect, in certain implementations of the third aspect, the first information includes parameters for the communication device to obtain the first time advance of the second base station, and the parameters include: the second time advance of the second base station, and the second time advance of the second base station is the time advance used in the access process with the second base station; the processing module is used to: initiate an access process to the second base station according to the second time advance of the second base station, and obtain the first time advance of the second base station during the access process.

[0028] In a fourth aspect, a communication device is provided, comprising: a generating module for generating first information, wherein the first information includes a first timing advance of a second base station, or the first information includes a parameter for the terminal device to obtain the first timing advance of the second base station, and the first timing advance is the timing advance used during data transmission between the terminal device and the second base station; and a sending module for sending the first information to the terminal device.

[0029] The method provided by the present application enables the terminal device to obtain the timing advance of the next base station in advance when facing the TA hopping problem caused by base station switching in the NTN scenario. In conjunction with the fourth aspect, in some implementations of the fourth aspect, the first information also includes: switching information between the communication device and the second base station, and the switching information includes the switching position and / or the switching time between the communication device and the second base station.

[0030] By adding the switching information of the first base station and the second base station to the first information, the terminal device can further achieve seamless switching between different base stations when switching satellites in the NTN scenario, avoiding service interruption caused by base station handover or signaling storm caused by switching.

[0031] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first information includes parameters for the terminal to obtain a first timing advance of the second base station, and the parameters include at least one of the following: the timing advance of the communication device, the location of the terminal device, and the location of the communication device or the second base station.

[0032] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first information includes parameters for the terminal to obtain a first time advance of the second base station, and the parameters include: a second time advance of the second base station, and the second time advance of the second base station is a time advance used in the access process with the second base station.

[0033] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first information is sent by the communication device in a broadcasting manner.

[0034] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first information is sent by the second base station to the communication device; and the device also includes: receiving the first indication information sent by the second base station.

[0035] In a fifth aspect, a communication device is provided, including a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that the communication device executes the method in the first aspect and its various possible implementations.

[0036] In a sixth aspect, a communication device is provided, including a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that the communication device executes the method in the second aspect and its various possible implementations.

[0037] In a seventh aspect, a computer-readable storage medium is provided for storing a computer program, wherein the computer program includes instructions for executing the method as in the first aspect or any possible implementation of the first aspect.

[0038] In an eighth aspect, a computer-readable storage medium is provided for storing a computer program, wherein the computer program includes instructions for executing the method in the second aspect or any possible implementation of the second aspect.

[0039] According to a ninth aspect, a computer program product is provided, comprising a computer program, which, when executed on a computer device, enables the computer device to execute the method according to the first aspect.

[0040] In a tenth aspect, a computer program product is provided, comprising a computer program, which, when executed on a computer device, enables the computer device to execute the method as described in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of a random access process in the prior art.

[0042] Figure 2 This is a schematic diagram of the principle of common TA in the NTN scenario.

[0043] Figure 3 It is a schematic diagram of the LEO satellite fixed cell mode in the prior art.

[0044] Figure 4 It is a schematic diagram of a communication method according to an embodiment of the present application.

[0045] Figure 5 It is a schematic diagram of another communication method of an embodiment of the present application.

[0046] Figure 6 It is a schematic diagram of a communication device according to an embodiment of the present application.

[0047] Figure 7 is a schematic diagram of another communication device according to an embodiment of the present application. DETAILED DESCRIPTION

[0048] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0049] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, long term evolution (LTE) system, fifth generation (5G) system or new radio (NR), as well as future evolved communication systems.

[0050] In this application, the terms "network" and "system" are often used interchangeably. The communication device described in this application refers to a network element in a communication system, such as a terminal, a base station (source base station, or target base station), and a core network device.

[0051] The terminal device in the embodiments of the present application may refer to user equipment, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device may also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G network or a terminal device in a future evolved public land mobile communication network (PLMN), etc., and the embodiments of the present application are not limited to this.

[0052] A base station may also be referred to as a base station device, which is a network device deployed in a wireless access network to provide wireless communication functions. The names of base stations may be different in different wireless access systems. For example, in the Universal Mobile Telecommunications System (UMTS) network, the base station is called a Node B (NodeB), in the LTE network, the base station is called an evolved Node B (evolved NodeB, eNB or eNodeB), and in the 5G system, it can be called a transceiver node (rransmissionreception point, TRP), gNode B (gNodeB, gNB). The base station may include one or more co-site or non-co-site TRPs. The base station may also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. The base station may also be a server, a wearable device, or a vehicle-mounted device, a non-ground device such as a satellite, etc. For ease of description, the base station is used for description below. Optionally, the base station in the present invention may also be a user device in a device-to-device D2D (Device to Device). Optionally, the base station and user equipment in the present invention may also be relay equipment, or network equipment or user equipment that implements a relay function.

[0053] The base station can be a centralized unit (CU) and a distributed unit (DU) separated architecture. The RAN can be connected to the core network (for example, it can be the core network of LTE, or it can be the core network of 5G, etc.). CU and DU can be understood as the division of the base station from the perspective of logical functions. CU and DU can be physically separated or deployed together. Multiple DUs can share one CU. One DU can also be connected to multiple CUs. The CU and DU can be connected through an interface, such as an F1 interface. CU and DU can be divided according to the protocol layer of the wireless network. For example, one possible division method is: CU is used to perform the functions of the radio resource control (RRC) layer, the service data adaptation protocol (SDAP) layer, and the packet data convergence protocol (PDCP) layer, while DU is used to perform the functions of the radio link control (RLC) layer, the media access control (MAC) layer, the physical layer, etc. It can be understood that the division of the CU and DU processing functions according to this protocol layer is only an example, and it can also be divided in other ways. For example, the CU or DU can be divided into functions with more protocol layers. For example, the CU or DU can also be divided into partial processing functions with protocol layers. In one design, some functions of the RLC layer and the functions of the protocol layers above the RLC layer are set in the CU, and the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer are set in the DU. In another design, the functions of the CU or DU can also be divided according to the service type or other system requirements. For example, according to the delay, the functions that need to meet the delay requirements for processing time are set in the DU, and the functions that do not need to meet the delay requirements are set in the CU. One or more CUs can be set centrally or separately. For example, the CU can be set on the network side for centralized management. The DU can have multiple radio frequency functions, or the radio frequency functions can be set remotely. The functions of the CU can be implemented by one entity or by different entities. For example, the functions of the CU can be further divided, for example, the control plane (CP) and the user plane (UP) are separated, that is, the control plane (CU-CP) of the CU and the user plane (CU-UP) of the CU. For example, the CU-CP and CU-UP may be implemented by different functional entities, and the CU-CP and CU-UP may be coupled with the DU to jointly complete the function of the base station.

[0054] In uplink transmission, different UEs use orthogonal multiple access in time and frequency, that is, uplink transmissions from different UEs in the same cell do not interfere with each other. In order to ensure the orthogonality of uplink transmission and avoid interference within the cell, the base station requires that the time when signals from different UEs in the same subframe but different frequency domain resources arrive at the base station is basically aligned. As long as the base station receives the uplink data sent by the UE within the cyclic prefix range, it can correctly decode the uplink data. Therefore, uplink synchronization requires that the time when signals from different UEs in the same subframe arrive at the base station falls within the cyclic prefix range. In order to maintain the orthogonality between uplink reference signals using different cyclic shifts, it is also required that the received uplink reference signals must be time-aligned. This is also the reason why uplink synchronization is needed to ensure that uplink transmissions from different UEs in the same cell are aligned in time. In order to ensure time synchronization on the receiving side (base station side), LTE / NR adopts the uplink timing advance mechanism. From the UE side, timing advance can be considered as a negative offset between the start time of the received downlink subframe and the time of transmitting the uplink subframe. The base station can control the time when uplink signals from different UEs arrive at the base station by appropriately controlling the offset of each UE. For UEs that are far away from the base station, due to the large transmission delay, uplink data must be sent earlier than UEs that are closer to the base station.

[0055] The base station has two ways to inform the UE of its TA. During the random access process, the base station determines the TA value by measuring the received preamble and sends the TA value to the UE through the timing advance command field of the RAR (LTE is 11 bits, corresponding to the TA index value T A The range of NR is 0-1282, and the range of NR is 12 bits, ranging from 0-3846) is sent to the UE. This process is the "initial uplink synchronization process". In the connected state, the base station needs to maintain the timing advance information. In theory, any signal sent by the UE (SRS / DMRS / CQI / ACK / NACK / PUSCH, etc.) can be used to measure the timing advance. The UE side will save the most recent TA adjustment value N TA,old When the UE receives a new timing advance command and gets T A After that, the latest TA adjustment value N will be calculated. TA,new =N TA,old +(T A -31)*16(unit is T s ).

[0056] Specifically, Figure 1FIG. 2 shows a schematic diagram of a process in which a base station informs a UE of its TA during a random access process in the prior art. Figure 1 As shown, the random access process includes steps S110 to S150. S110, random access initialization, in which parameters are configured, and these parameters may include: a physical random access channel (PRACH) resource set that can be used to transmit a random access preamble; available random access preamble groups (Group A or Group B) and available preamble sets in each group; maximum number of preamble transmissions; initial preamble transmission power; power boost step; random access response window; maximum number of hybrid automatic repeat request (HARQ) retransmissions of the third message; contention resolution timer, etc. S120, the terminal device sends a random access preamble (RAP) to the network device. The function of the random access preamble is mainly to notify the network device that there is a random access request and enable the network device to estimate the transmission delay between it and the terminal device, so that the access network device can calibrate the uplink advance (uplink timing) and inform the terminal device of the calibration information through the timing advance command. S130, the terminal device receives a random access response (RAR) sent by the network device, wherein the RAR includes an uplink timing advance, which is determined by the network device according to the received random access preamble. S140, the terminal device sends a message based on scheduled transmission to the network device. S150, the terminal device receives a contention resolution message sent by the network device, confirming that the random access process is successful.

[0057] In order to shorten the random access delay, the 5G NR system supports not only the current traditional four-step random access method, but also a two-step random access method. The two-step random access method includes the terminal device sending a first message to the base station, the first message may include a preamble code and / or a demodulation reference signal (DMRS), and the base station sends a second message to the terminal device, the second message may include a response message, and the response message may include temporary C-RNTI information, timing advance command (TA command) information, uplink authorization information, contention resolution identifier, etc. Since the two-step random access method belongs to the prior art, this application will not go into details about it.

[0058] It should be understood that the embodiments of the present application are not only applicable to Figure 1The four-step random access method in is also applicable to the two-step random access method.

[0059] Satellite communication (non-terrestrial network, NTN), that is, non-terrestrial communication. Thanks to the current concept of "any time, any place" communication, the status of satellite communication network will be further improved in the future. Generally speaking, the higher the orbit of the satellite, the larger its coverage area, but the longer the communication delay. Generally speaking, the orbit of the satellite can be divided into: low orbit (low earth orbit, LEO): orbit altitude of 160 ~ 2000km; middle orbit (middle earth orbit, MEO): orbit altitude of 2000 ~ 35786km; geostationary earth orbit (geostationary earth orbit, GEO): orbit altitude of 35786km, the relative position of the satellite running in this orbit and the earth is not affected by the rotation of the earth. Among them, low-orbit communication satellites are close to the ground, have short communication delays, high data transmission rates, and the weight and volume of mobile terminals are almost the same as those of personal mobile devices. They are more suitable for popularization in the mass market and have become a hot spot for current industrial development.

[0060] Due to the long delay of satellite communication, the timing advance mechanism designed for the current NR system cannot be applied to satellite communication. In the timing advance mechanism in the prior art, the value range of TA is 0-3486, and the length represented by a TA value is: 39m when PRACH subcarrier = 30KHZ, 78m when 15KHZ, and in the random access process in the prior art, the timing advance sent to the UE carried in the random access response message sent by the base station can cover a range of approximately 300km, while the satellite in satellite communication has an orbital altitude of more than 600-km. Obviously, the timing advance mechanism of the prior art cannot adapt to satellite communication. In order to adapt to satellite communication, the prior art proposes that the UE can be informed of its timing advance by broadcasting common TA by satellite. Figure 2 The schematic diagram of the principle of a common TA mechanism is shown. The satellite selects a reference point on the ground, which is generally the point closest to the satellite and the ground, with a distance of d0. The TA at this distance is the common TA. The TA sent by the base station to the UE is Figure 2The UE specific TA in the TA value has been subtracted from the common TA distance, so it can be represented by 12 bits in the timing advance command field in the RAR. However, the current common TA mechanism only involves the broadcast of the common TA of the cell, and does not take into account the TA hopping problem during satellite switching or handover in the NTN scenario, which may trigger the UE's beam failure recovery, causing NTN service interruption and affecting communication quality.

[0061] In the LEO cell, because LEO is flying around the earth at a high speed, its speed is close to 7km / s. There are two modes of cells projected by LEO satellites to the ground. One is the moving cell mode, in which the cell projected by the satellite to the ground moves with the satellite, and the relative distance between the LEO satellite and the UE is constantly changing. When the signal of the current LEO satellite cannot cover the UE, the next LEO satellite will cover the UE. The other is the fixed cell mode. Figure 3 Schematic diagram of cell coverage in fixed cell mode is shown. Figure 3 As shown in the figure, in this mode, the cell projected by the LEO satellite to the ground is stationary relative to the ground. The LEO satellite completes the coverage of the same position on the ground by adjusting the antenna angle. When the LEO satellite cannot cover the ground, it will be switched (handed over) by another LEO satellite. In the above two modes, when the LEO satellite is switched, the distance between the UE and the LEO satellite will jump. The jump in distance causes the jump in TA. If no compensation is made in advance, the communication between the UE and the satellite will fail.

[0062] A UE in a connected state will always be in a state of measuring signals. For some reasons, such as movement, when the measurement results trigger certain conditions, the UE will report the measurement results to the base station, and the base station will send a handover command to the UE, and the UE will switch to a cell with better quality. Under the existing mechanism, if it is a fixed cell, because the various parameters of the cell remain unchanged, when the two satellites are handed over, the UE will not be aware, and there will be no cell reselection or handover. If the current mechanism is used, the UE will be immediately interrupted due to beam failure recovery; if it is a moving cell, a large number of UEs need to switch, and LEO needs to send handover commands to UEs with a large amount of data, which is easy to cause a signaling storm.

[0063] In the embodiment of the present application, for the TA hopping problem in the NTN scenario, the terminal device can obtain the time advance of the next base station in advance. It should be understood that the base station in the embodiment of the present application can be one or more ground stations, one or more satellites, or a combination of one or more satellites and ground stations, collectively referred to as access network equipment.

[0064] Furthermore, the terminal device communicates with the second base station according to the time advance and the switching information between base stations, thereby achieving seamless connection with the next base station. Figure 4 A schematic diagram of a communication method according to an embodiment of the present application is shown. Figure 4 As shown, the method 400 includes steps S410 and S420, which are described in detail below.

[0065] S410, the terminal device receives first information sent by the first base station.

[0066] As an embodiment, the first information may include a first timing advance of the second base station, and the first timing advance may be a timing advance used in the data transmission process with the second base station. Optionally, the first timing advance may be calculated by the first base station based on multiple parameters, and the multiple parameters may include at least one of the following: the timing advance of the first base station, the location of the terminal device, the location of the first base station, or the location of the second base station. Or the first timing advance may be obtained by the first base station based on mapping relationship information, and the mapping relationship information may be a mapping relationship between multiple parameter groups and multiple timing advances, and each parameter group may include the value of at least one of the following parameters: the timing advance of the first base station, the location of the terminal device, the location of the first base station, or the location of the second base station. Optionally, the base stations may know each other's locations through an ephemeris map. Optionally, the location of the second base station may be sent by the second base station to the first base station.

[0067] As another embodiment, the first information may include a parameter used by the terminal device to acquire a first timing advance of the second base station, where the first timing advance is a timing advance used by the terminal device during data transmission with the second base station.

[0068] Optionally, the first information may include parameters for the terminal device to obtain the first timing advance of the second base station, and the parameters may include the timing advance of the first base station, the location of the terminal device, the location of the first base station, or the location of the second base station. The terminal device may calculate the first timing advance based on the above multiple parameters. Or the first information may include mapping relationship information, and the mapping relationship information is used to indicate the mapping relationship between multiple parameter groups including the first parameter group and multiple timing advances, and each parameter group includes the value of at least one of the following parameters: the timing advance of the first base station, the location of the terminal device, the location of the first base station, or the location of the second base station. Optionally, the mapping relationship information may be sent by the first base station to the terminal device, or the mapping relationship information may be configured by the terminal device itself, which is not limited in this application.

[0069] Optionally, the first information may include a second timing advance of the second base station, the second timing advance is a timing advance used by the terminal device to send a preamble during a random access process with the second base station, and optionally, the second timing advance may be a common timing advance of the second base station. The second timing advance may be known by the two base stations after establishing an xn interface for interaction.

[0070] Optionally, the first information may be sent by the first base station in a broadcasting manner.

[0071] As another embodiment, the first information may be sent by the second base station to the first base station, such as Figure 5 FIG. 5 is a schematic diagram of another communication method according to an embodiment of the present application. The method 500 includes step S510.

[0072] S510: A first base station receives first information sent by a second base station.

[0073] As an embodiment, the first information includes a first timing advance of the second base station, or the first information includes a parameter used by a terminal device to obtain a first timing advance of the second base station, and the first timing advance is a timing advance used during data transmission with the second base station.

[0074] The method for the terminal device to obtain the first time advance is the same as the process in method 400, and will not be described in detail here.

[0075] Optionally, the first information may be sent through an XN interface.

[0076] S420, the terminal device obtains the first timing advance of the second base station through the first information.

[0077] As an embodiment, when the first information includes the first timing advance of the second base station, the terminal device can directly obtain the first timing advance of the second base station from the first information.

[0078] As another embodiment, the terminal device may calculate the first timing advance of the second base station according to the parameters included in the first information. Or the first information may further include mapping relationship information, and the terminal device determines the timing advance corresponding to the first parameter group indicated by the first information as the first timing advance according to the mapping relationship information. The parameter or parameter group may include at least one of the following: the timing advance of the first base station, the location of the terminal device, the location of the first base station, or the location of the second base station.

[0079] As another embodiment, the terminal device may obtain the first time advance according to the parameter included in the first information, and the parameter may be the second time advance of the second base station. Optionally, the second time advance may be the common time advance of the second base station. The terminal device may initiate a random access process to the second base station according to the second time advance of the second base station, and obtain the first time advance of the second base station during the random access process. Optionally, the second time advance of the second base station is at least two. In this case, the first information may include a correspondence between at least two second time advances and at least two moments, and the moment may be an absolute moment or a relative moment. The correspondence may be a list or a formula, such as common TA=SFN*100+6000. The terminal device may select a suitable moment from the above correspondence according to the time of initiating random access, and select the second time advance corresponding to the moment. The terminal device may initiate a random access process according to the second time advance. Figure 1 The random access process shown. Specifically, the terminal device can determine the first moment from the above correspondence according to the time when the random access is initiated, and determine the second time advance according to the first moment, and then send a random access preamble to the second base station according to the second time advance, and then receive the third time advance sent by the second base station, and determine the first time advance according to the second time advance and the third time advance, and optionally, the first time advance can be the sum of the second time advance and the third time advance. Optionally, the third time advance is determined by the second base station according to the preamble, and the third time advance can be a positive number, or the third time advance can be a negative number.

[0080] Since the movement of the terminal device or the base station may cause the time advance therebetween to change, the terminal device selects a suitable time advance as the second time advance from the corresponding relationship according to the time of initiating random access. This can enable the terminal device to send the preamble code more accurately in the switching scenario, thereby improving the success rate of the base station processing the preamble code, thereby improving the success rate of random access.

[0081] In the prior art, in the NTN scenario, the third time advance determined by the base station based on the preamble code has taken the commonTA into account, which is generally the UE's TA minus the common TA. Because in the prior art, when the satellite selects a reference point, the default reference point selected is the point closest to the ground, so the second time advance obtained by the base station is a positive number. However, if the selected reference point is not the shortest distance between the satellite and the ground, the common TA is larger than the actual TA of the UE. In this case, the TA carried in the RAR may be a positive number, but in the existing mechanism, the TA carried in the RAR is a positive number, so a TA value representing a negative number can be introduced. After receiving the TA in the RAR, the UE can optionally calculate the TA value according to the TA. new =TA old +(TA RAR -N) to calculate, where TA old Refers to the common TA read by the UE. N can be any positive number between 0 and the maximum TA. This rule can be written into the protocol or broadcast.

[0082] As an embodiment, the first information may also include switching information between the first base station and the second base station, and the switching information may include the switching position and / or the switching time between the first base station and the second base station. The terminal device may communicate with the second base station based on the first time information of the second base station and the switching information between the first base station and the second base station. Optionally, the switching position may be a relative position or an absolute position, which is used to adjust the angle of the UE antenna; the switching time may be an absolute time or a relative time, which is used to notify the UE of the next satellite switching time. By knowing the first time advance of the second base station in advance, and based on the switching information between the first base station and the second base station, the terminal device can be connected to other base stations without interrupting the service, or can avoid the signaling storm caused by the base station needing to send a large number of switching messages to the terminal device, so that the terminal device can seamlessly switch to the next base station after the satellite (base station) is switched in the NTN scenario.

[0083] If the NTN system does not adopt the above TA compensation mechanism, or for other reasons, the UE may trigger cell selection or reselection due to loss of connection with the original satellite.

[0084] In the prior art, when a terminal device is powered on or a wireless link failure occurs, the UE will perform a cell search process and select a suitable cell to reside in as quickly as possible. This process is called "cell selection". During the cell search process, the UE will read the system information of the cell and obtain the Q rxlevmeas , Q rxlevmin and Q rxlevminoffset The UE evaluates whether the cell is a suitable cell according to the S criterion. The S criterion formula is: Srxlev>0, Srxlev=Q rxlevmeas -(Q rxlevmin +Q rxlevminoffset )-P compensation -Qoffset temp , that is, if the S value of a cell is greater than 0, it means that the cell is a suitable cell (a cell suitable for residence).

[0085] Among them, Srxlev refers to the level value calculated during the cell selection / reselection process; Q rxlevmeas It refers to the received signal strength value measured by the UE, which is the measured reference signal received power; Q rxlevmin It refers to the minimum received signal strength value required by the cell, which is in the Q rxlevmin Instructions: P compensation is max(PE MAX –PU MAX , 0), where PE MAX The maximum allowed transmit power set by the system when the terminal accesses the cell; PU MAX Refers to the maximum output power specified according to the terminal level. rxlevminoffset This parameter is only valid when the user is normally stationed in a visited public land mobile network (VPLMN) and periodically searches for a high-priority PLMN for cell selection evaluation. rxlevmin Make some bias.

[0086] When an IDLE UE resides in a cell, as the UE moves, the UE may need to switch to another cell with a higher priority or better signal. This is the cell reselection process. After measuring each cell, the terminal device will determine whether to reselect to a new cell. The reselection criteria are as follows:

[0087] Reselection criteria for high-priority frequencies or systems: Srxlev of the target frequency cell > Threshx,high and lasts for TreselectionRAT time (where Threshx,high is the threshold and TreselectionRAT is the time interval); Reselection criteria for low-priority frequencies or systems: Srxlev of the serving cell < Threshserving,low, and Srxlev of the target frequency cell > Threshx,low and lasts for TreselectionRAT time; Reselection criteria for same-priority frequencies or systems: Cell reselection to a cell in the same-priority frequency is based on the Ranking criteria for intra-frequency cell reselection. As follows, where Rs is the ranking value of the current serving cell and Rn is the ranking value of the neighboring cell: Rs = Q meas,s +Q hyst -Qoffste temp ; Rn = Q meas,n -Qoffset-Qoffset temp 。Among them, Q hyst is the hysteresis value, used to prevent ping-pong reselection; Q meas is the received signal strength value of the cell measured by the UE; Qoffset: For intra-frequency, the value is Qoffset,n; For inter-frequency, the value is Qoffsets,n + Qoffsetfrequency; The UE will rank the values of all cells that meet the cell selection S criteria.

[0088] In the NTN scenario, if the UE moves from one GEO / LEO to a cell covered by another GEO / LEO, the distance between the UE and the GEO / LEO changes, and the common TA may also change (the reference points of each base station are selected differently). To enable the UE to access more smoothly, before receiving the first information sent by the first base station, the terminal device in the embodiment of the present application may also receive the fourth time advance sent by at least one base station. The fourth time advance may be the common time advance of at least one base station, and convert the fourth time advance into a bias, such as Qoffset common TA , and substitute the bias into the above cell selection or cell reselection formula to determine the second base station. Optionally, the fourth time advance sent by the at least one base station may be the time advance of the first base station and / or the time advance of the neighboring base station. Optionally, the conversion relationship between the fourth time advance and the converted bias may be inversely proportional, or a mathematical formula such as subtracting a certain value. The conversion relationship may be broadcast in the system message or written into the protocol.

[0089] By using the time advance as a reference in cell selection and / or cell reselection, the terminal device can select a more suitable cell for access, thereby improving the communication quality.

[0090] Optionally, the bias in the above application embodiment can be applied to the switching of a terminal device in a connected state, and can also be applied to the cell selection and / or cell reselection of a terminal device in an idle state, and the present application does not limit this.

[0091] Figure 6 A schematic diagram of a communication device according to an embodiment of the present application is shown. Figure 6 As shown, the device 600 includes a receiving module 610 and a processing module 620 .

[0092] The receiving module is used to receive first information sent by a first base station, where the first information includes a first time advance of a second base station, or the first information includes a parameter used by the device 600 to obtain the first time advance of the second base station, and the first time advance is the time advance used during data transmission with the second base station; the processing module is used to obtain the first time advance of the second base station through the first information.

[0093] Optionally, the first information further includes: switching information between the first base station and the second base station, and the switching information includes a switching position and / or a switching time between the first base station and the second base station.

[0094] Optionally, the device further includes: a communication module, configured to communicate with the second base station according to the first timing advance of the second base station and the switching information between the first base station and the second base station.

[0095] Optionally, the first information includes parameters for the device 600 to obtain the first time advance of the second base station, and the parameters include at least one of the following: the time advance of the first base station, the location of the device 600, the location of the first base station or the location of the second base station; the processing module is used to: calculate the first time advance of the second base station according to the parameters.

[0096] Optionally, the first information includes parameters for the device 600 to obtain the first time advance of the second base station, and the parameters include: the second time advance of the second base station, the second time advance of the second base station is the time advance used in the access process with the second base station; the processing module is used to: initiate an access process to the second base station according to the second time advance of the second base station, and obtain the first time advance of the second base station during the access process.

[0097] The communication device 600 may also be implemented in other ways, such as by at least one processor, memory, and transceiver. The function of the receiving module 610 may be implemented by a transceiver, and the function of the processing module 620 may be implemented by a processor, which may implement the above solution by calling a program in the memory.

[0098] Figure 7 A schematic diagram of another communication device according to an embodiment of the present application is shown. Figure 7 As shown, the device 700 includes a generating module 710 and a sending module 720 .

[0099] A generating module 710 is configured to generate first information, where the first information includes a first timing advance of a second base station, or the first information includes a parameter used by the terminal device to obtain a first timing advance of the second base station, where the first timing advance is a timing advance used during data transmission between the terminal device and the second base station;

[0100] The sending module is used to send the first information to the terminal device.

[0101] Optionally, the first information further includes: switching information between the apparatus 700 and the second base station, the switching information including a switching position and / or a switching time between the apparatus 700 and the second base station.

[0102] Optionally, the first information includes parameters for the terminal to obtain a first timing advance of the second base station, and the parameters include at least one of the following: the timing advance of the apparatus 700, the location of the terminal device, or the location of the apparatus 700 or the second base station.

[0103] Optionally, the first information includes parameters for the terminal to obtain a first timing advance of the second base station, the parameters including: a second timing advance of the second base station, the second timing advance of the second base station being a timing advance used in an access process with the second base station.

[0104] Optionally, the first information is sent by the device 700 in a broadcasting manner.

[0105] Optionally, the first information is sent by the second base station to the device 700; and the device also includes: receiving the first indication information sent by the second base station.

[0106] The communication device 700 may also be implemented in other ways, such as by at least one processor, memory, and transceiver. The function of the sending module 720 may be implemented by a transceiver, and the function of the generating module 710 may be implemented by a processor, which may implement the above solution by calling a program in the memory.

[0107] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative, for example, the division of the modules is only a logical function division, and there may be other division methods in actual implementation.

[0108] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part 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, the process or function described in the embodiment of the present invention is generated in whole or in part. 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 computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

Claims

1. A communication method, characterized in that: include: Receive first information sent by a first base station, where the first information includes a first timing advance of a second base station, or the first information includes a parameter used by a terminal device to obtain a first timing advance of the second base station, where the first timing advance is a timing advance used in a data transmission process with the second base station; A first timing advance of the second base station is acquired through the first information.

2. The method according to claim 1, characterized in that The first information also includes: The switching information between the first base station and the second base station includes a switching position and / or a switching time between the first base station and the second base station.

3. The method according to claim 2, characterized in that: The method further comprises: Communicate with the second base station according to the first timing advance of the second base station and the switching information between the first base station and the second base station.

4. The method according to any one of claims 1 to 3, characterized in that The first information includes a parameter used by the terminal device to obtain a first timing advance of the second base station, and the parameter includes at least one of the following: The timing advance of the first base station, the location of the terminal device, the location of the first base station or the location of the second base station; The acquiring the first timing advance of the second base station by using the first information includes: A first timing advance of the second base station is obtained by calculation according to the parameter.

5. The method according to any one of claims 1 to 4, characterized in that The first information includes parameters used by the terminal device to obtain a first timing advance of the second base station, and the parameters include: A second timing advance of the second base station, where the second timing advance of the second base station is a timing advance used in an access process with the second base station; The acquiring the first timing advance of the second base station by using the first information includes: According to the second timing advance of the second base station, an access process is initiated to the second base station, and the first timing advance of the second base station is acquired.

6. A communication method, characterized in that: include: The first base station generates first information, where the first information includes a first timing advance of the second base station, or the first information includes a first timing advance parameter used by a terminal device to obtain the second base station, where the first timing advance is a timing advance used during data transmission between the terminal device and the second base station; The first base station sends the first information to the terminal device.

7. The method according to claim 6, characterized in that The first information also includes: The switching information between the first base station and the second base station includes a switching position and / or a switching time between the first base station and the second base station.

8. The method according to claim 6 or 7, characterized in that: The first information includes a parameter used by the terminal to obtain a first timing advance of the second base station, and the parameter includes at least one of the following: The timing advance of the first base station, the location of the terminal device, and the location of the first base station or the second base station.

9. The method according to any one of claims 6 to 8, characterized in that: The first information includes a parameter used by the terminal to obtain a first timing advance of the second base station, and the parameter includes: The second timing advance of the second base station, the second timing advance of the second base station is the timing advance used by the terminal device during the access process with the second base station.

10. The method according to any one of claims 6 to 9, characterized in that: The first information is sent by the first base station in a broadcasting manner.

11. The method according to any one of claims 6 to 10, characterized in that: The first information is sent by the second base station to the first base station; and the method further includes: Receive the first indication information sent by the second base station.

12. A communication device, characterized in that: include: a receiving module, configured to receive first information sent by a first base station, where the first information includes a first timing advance of a second base station, or the first information includes a parameter used by the communication device to obtain a first timing advance of the second base station, where the first timing advance is a timing advance used in a data transmission process with the second base station; A processing module is used to obtain a first timing advance of the second base station through the first information.

13. The device according to claim 12, characterized in that The first information also includes: The switching information between the first base station and the second base station includes a switching position and / or a switching time between the first base station and the second base station.

14. The device according to claim 13, characterized in that The device also includes: A communication module is used to communicate with the second base station according to the first timing advance of the second base station and the switching information between the first base station and the second base station.

15. The device according to any one of claims 12 to 14, characterized in that The first information includes a parameter used by the communication device to obtain a first timing advance of the second base station, and the parameter includes at least one of the following: the timing advance of the first base station, the location of the communication device, the location of the first base station or the location of the second base station; The processing module is used for: A first timing advance of the second base station is obtained by calculation according to the parameter.

16. The device according to any one of claims 12 to 15, characterized in that The first information includes parameters used by the communication device to obtain a first timing advance of the second base station, and the parameters include: A second timing advance of the second base station, where the second timing advance of the second base station is a timing advance used in an access process with the second base station; The processing module is used for: According to the second timing advance of the second base station, an access process is initiated to the second base station, and the first timing advance of the second base station is acquired.

17. A communication device, characterized in that: include: A generating module, configured to generate first information, wherein the first information includes a first timing advance of a second base station, or the first information includes a parameter used by a terminal device to obtain a first timing advance of the second base station, and the first timing advance is a timing advance used in a data transmission process between the terminal device and the second base station; A sending module is used to send the first information to the terminal device.

18. The device according to claim 17, characterized in that The first information also includes: The switching information between the communication device and the second base station includes the switching position and / or the switching time between the communication device and the second base station.

19. The device according to claim 17 or 18, characterized in that The first information includes a parameter used by the terminal to obtain a first timing advance of the second base station, and the parameter includes at least one of the following: The timing advance of the communication device, the location of the terminal equipment, and the location of the communication device or the second base station.

20. The device according to any one of claims 17 to 19, characterized in that The first information includes a parameter used by the terminal to obtain a first timing advance of the second base station, and the parameter includes: The second timing advance of the second base station is a timing advance used in an access process with the second base station.

21. The device according to any one of claims 17 to 20, characterized in that The first information is sent by the communication device in a broadcasting manner.

22. The device according to any one of claims 17 to 21, characterized in that The first information is sent by the second base station to the communication device; and the device further includes: Receive the first indication information sent by the second base station.

23. A computer-readable storage medium, characterized in that: Used to store a computer program, which, when executed, causes the method according to any one of claims 1 to 11 to be performed.

24. A computer program product, characterized in that The method comprises a computer program, which, when executed on a computer device, causes the computer device to execute the method according to any one of claims 1 to 11.

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