Terminal switching method, terminal, network side equipment, network equipment and system

Abstract

The invention provides a terminal switching method, a terminal, network side equipment, network equipment and a system, and relates to the technical field of wireless communication. The terminal switching method disclosed by the invention comprises the following steps: a terminal located in a non-ground network receives a no-random access channel switching instruction, and the no-random access channel switching instruction comprises timing advance compensation auxiliary information; the terminal determines a timing advance compensation value according to the timing advance compensation auxiliary information; and the terminal sends initial access information to the non-terrestrial network based on the timing advance compensation value.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless communication technology, and in particular to a terminal switching method, a terminal, a network side device, a network device and a system. Background Art

[0002] With the freezing of 3GPP R17 version, the Non-Terrestrial Network (NTN) introduced satellite nodes into the mobile communication network. Terminals can access the network via satellite, greatly improving the network coverage.

[0003] The communication delay of satellite nodes is much greater than that of terrestrial cellular networks, and excessive delay can easily lead to switching failures. Summary of the invention

[0004] An object of the present disclosure is to propose a handover solution for a terminal in an NTN to improve the success rate of handover.

[0005] According to one aspect of some embodiments of the present disclosure, a terminal switching method is proposed, including: a terminal located in an NTN (non-terrestrial network) receives a RACH-less (Random Access Channel-less) switching instruction, wherein the RACH-less switching instruction includes TA (Time Advance, TA) compensation auxiliary information; the terminal determines a TA compensation value according to the TA compensation auxiliary information; and the terminal sends initial access information to the NTN based on the TA compensation value.

[0006] In some embodiments, the TA compensation assistance information includes ephemeris information.

[0007] In some embodiments, the TA compensation assistance information also includes feeder link TA compensation information.

[0008] In some embodiments, the RACH-less switching instruction also includes pre-allocated time-frequency resource configuration information, and the terminal switching method further includes: the terminal storing the time-frequency resource configuration information.

[0009] In some embodiments, the method further includes: the terminal obtains and stores the pre-allocated time-frequency resource configuration information through RRC (Radio Resource Control) information.

[0010] In some embodiments, the terminal sending initial access information to the NTN based on the TA compensation value includes: after the terminal determines the TA compensation value, according to the stored time-frequency resource configuration information, sending the initial access information to the NTN based on the TA compensation value.

[0011] In some embodiments, the method further includes: the terminal receives dynamic authorization information of the target cell through DCI (Downlink Control Information); the terminal sends initial access information to the NTN based on the TA compensation value, including: after receiving the dynamic authorization information, the terminal sends initial access information to the NTN based on the TA compensation value according to the dynamic authorization information.

[0012] In some embodiments, the terminal determines the TA compensation value according to the TA compensation auxiliary information, including: determining the feeder circuit TA compensation value according to the feeder link TA compensation information; determining the specific user equipment TA compensation value according to the ephemeris information; determining the TA compensation value according to the feeder circuit TA compensation value and the specific user equipment TA compensation value.

[0013] In some embodiments, the terminal determines the TA compensation value based on the TA compensation auxiliary information, which also includes: the terminal determines the TA compensation measurement value; determining the TA compensation value based on the feed circuit TA compensation value and the specific user equipment TA compensation value includes: determining the TA compensation value based on the feed circuit TA compensation value and the specific user equipment TA compensation value, combined with the TA compensation measurement value, TA offset and unit time length.

[0014] In some embodiments, determining the TA compensation measurement value includes: when the source cell and the target cell correspond to the same satellite, the TA compensation measurement value is the same as the source cell.

[0015] In some embodiments, determining the TA compensation measurement value includes: when the source cell and the target cell correspond to different satellites, the TA compensation measurement value is a predetermined value.

[0016] In some embodiments, the method further includes: the terminal receiving access confirmation information, and the terminal determining that the access is successful according to the access confirmation information.

[0017] In some embodiments, the access confirmation information is carried by a MAC (Medium Access Control, link layer) CE (Control Element, control element).

[0018] In some embodiments, the method also includes: the terminal obtains downlink data through PDCCH (Physical Downlink Control Channel) or PDSCH (Physical Uplink Shared Channel) encrypted by C-RNTI (Cell-Radio Network Temporary Identifier), wherein the terminal determines that access is successful based on the downlink data.

[0019] According to one aspect of some embodiments of the present disclosure, a terminal switching method is proposed, including: a network side device of an NTN sends switching preparation information to a target cell to which the terminal switches; the network side device sends a RACH-less switching instruction, wherein the RACH-less switching instruction includes TA compensation auxiliary information.

[0020] In some embodiments, the RACH-less switching instruction also includes time-frequency resource configuration information pre-allocated to the terminal.

[0021] In some embodiments, the method further includes: sending pre-allocated time-frequency resource configuration information to the terminal via RRC information.

[0022] In some embodiments, the method further includes: receiving dynamic authorization information from the target cell; and sending the dynamic authorization information to the terminal via DCI.

[0023] According to one aspect of some embodiments of the present disclosure, a terminal switching method is proposed, including: a network side device of an NTN obtains switching preparation information from a source cell of a terminal switching; the network side device obtains initial access information of the terminal; and downlink data is sent via a PDCCH or PDSCH scrambled by a C-RNTI.

[0024] In some embodiments, the method further comprises: sending access confirmation information to the terminal.

[0025] In some embodiments, the access confirmation information is carried by MAC CE.

[0026] In some embodiments, the method further includes: after receiving the switching preparation information, the network side device generates dynamic authorization information of the terminal; and sends the dynamic authorization information to the source cell.

[0027] According to one aspect of some embodiments of the present disclosure, a terminal is proposed, comprising: an information acquisition unit, configured to receive a RACH-less switching instruction from a source cell of an NTN, the RACH-less switching instruction including TA compensation auxiliary information; a compensation value determination unit, configured to determine a TA compensation value according to the TA compensation auxiliary information; and an access unit, configured to send initial access information to a target cell of the NTN based on the TA compensation value.

[0028] In some embodiments, the TA compensation assistance information includes ephemeris information and feeder link TA compensation information.

[0029] In some embodiments, the RACH-less switching instruction also includes pre-allocated time-frequency resource configuration information, and the information acquisition unit is further configured to store the time-frequency resource configuration information.

[0030] In some embodiments, the information acquisition unit is further configured to acquire and store the pre-allocated time-frequency resource configuration information through RRC information.

[0031] In some embodiments, the access unit is configured to send initial access information to the NTN based on the TA compensation value according to the stored time-frequency resource configuration information after the compensation value determination unit determines the TA compensation value.

[0032] In some embodiments, the information acquisition unit is further configured to receive dynamic authorization information of the target cell through DCI; the access unit is configured to send initial access information to the NTN based on the TA compensation value according to the dynamic authorization information after receiving the dynamic authorization information.

[0033] In some embodiments, the information acquisition unit is further configured to perform at least one of the following: receiving access confirmation information, wherein the terminal determines that the access is successful based on the access confirmation information; or obtaining downlink data through a PDCCH or PDSCH encrypted by C-RNTI, wherein the terminal determines that the access is successful based on the downlink data.

[0034] According to one aspect of some embodiments of the present disclosure, a network side device of NTN is proposed, including: a switching preparation interaction unit, configured to send switching preparation information to a target cell for terminal switching; an information sending unit, configured to send a RACH-less switching instruction, wherein the RACH-less switching instruction includes TA compensation auxiliary information.

[0035] In some embodiments, the RACH-less switching instruction also includes time-frequency resource configuration information pre-allocated to the terminal.

[0036] In some embodiments, the information sending unit is further configured to send pre-allocated time-frequency resource configuration information to the terminal via radio resource control information.

[0037] In some embodiments, the handover preparation interaction unit is further configured to receive dynamic authorization information from the target cell; and the information sending unit is further configured to send the dynamic authorization information to the terminal via downlink control information.

[0038] According to one aspect of some embodiments of the present disclosure, a network side device of NTN is proposed, including: a switching preparation unit, configured to obtain switching preparation information from a source cell of a terminal switching; an access information receiving unit, configured to obtain initial access information of the terminal; and an access confirmation unit, configured to send downlink data through a physical downlink control channel or a physical downlink shared channel scrambled by a cell radio network temporary identifier.

[0039] In some embodiments, the access confirmation unit is further configured to send access confirmation information to the terminal.

[0040] In some embodiments, the handover preparation unit is further configured to generate dynamic authorization information of the terminal after receiving the handover preparation information, and send the dynamic authorization information to the source cell.

[0041] According to one aspect of some embodiments of the present disclosure, a network device is provided, comprising: a memory; and a processor coupled to the memory, wherein the processor is configured to execute any one of the above-mentioned methods based on instructions stored in the memory.

[0042] According to one aspect of some embodiments of the present disclosure, a computer-readable storage medium is provided, on which computer program instructions are stored, and when the instructions are executed by a processor, the steps of any one of the methods mentioned above are implemented.

[0043] According to one aspect of some embodiments of the present disclosure, a network side system of NTN is proposed, including: a first network side device, configured to execute any one of the terminal switching methods on the source cell side of the terminal switching mentioned above; and a second network side device, configured to execute any one of the terminal switching methods on the target cell side of the terminal switching mentioned above.

[0044] According to one aspect of some embodiments of the present disclosure, an NTN system is proposed, comprising: a terminal, configured to execute any one of the methods performed by the terminal as described above; and a network side device, wherein at least one network side device is configured to execute any one of the terminal switching methods on the source cell side of the terminal switching mentioned above; and at least one network side device is configured to execute any one of the terminal switching methods on the target cell side of the terminal switching mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings:

[0046] Figure 1 The present invention is a flowchart of some embodiments of the terminal switching method disclosed herein.

[0047] Figure 2 Flow charts of other embodiments of the terminal switching method disclosed in the present invention.

[0048] Figure 3 Flowcharts of some further embodiments of the terminal switching method disclosed herein.

[0049] Figure 4 The present invention is a signaling flow chart of some embodiments of the terminal switching method disclosed in the present invention.

[0050] Figure 5The present invention is a signaling flow chart of other embodiments of the terminal switching method disclosed herein.

[0051] Figure 6 Schematic diagrams of some embodiments of the terminal disclosed herein.

[0052] Figure 7 Schematic diagram of some embodiments of the network side device of the NTN disclosed in the present invention.

[0053] Figure 8 Schematic diagrams of other embodiments of the NTN network side device of the present disclosure.

[0054] Fig. 9 Schematic diagram of some embodiments of the network device disclosed herein.

[0055] Fig.10 Schematic diagrams of other embodiments of the network device disclosed herein.

[0056] Fig.11 Schematic diagrams of some embodiments of the network side system of the NTN disclosed in the present invention.

[0057] Fig.12 Schematic diagrams of some embodiments of the NTN system disclosed herein. DETAILED DESCRIPTION

[0058] The technical solution of the present disclosure is further described in detail below through the accompanying drawings and embodiments.

[0059] RACH-less is a method that can skip the random access process and directly switch to the target cell, which can greatly shorten the access delay. However, the existing standards in the related technology only support the RACH-less solution for terrestrial cellular networks, and the TA compensation value is only 0 or the same as the source cell base station. However, the TA compensation process for non-terrestrial networks is relatively complex, and factors such as the feeder link, ephemeris information, and terminal location information need to be considered at the same time. In addition, due to the high communication delay, the communication process should be simplified as much as possible to reduce the frequent interaction between the terminal and the network.

[0060] The flowcharts of some embodiments of the terminal switching method disclosed in the present invention are as follows: Figure 1 shown. Figure 1 The terminal switching method is executed by a terminal, which is a terminal provided with wireless access service by NTN, or a terminal supporting the acquisition of network service capability through NTN.

[0061] In step 111, a terminal located at the NTN receives a RACH-less HO instruction, and the RACH-less HO instruction includes TA compensation auxiliary information. In some embodiments, the TA compensation auxiliary information is information required by the terminal to calculate the TA compensation value. In some embodiments, the TA compensation auxiliary information includes ephemeris information and feeder link TA compensation information, so that the terminal can obtain parameters for implementing TA compensation of the NTN and improve access efficiency. In some embodiments, the ephemeris information in the auxiliary information is the ephemeris information of the target cell.

[0062] In some embodiments, the RACH-less switching instruction may be issued by a network side device of a source cell (hereinafter referred to as the source cell, such as a satellite providing services to the source cell). In some embodiments, after determining that the terminal needs to perform RACH-less switching, the source cell performs switching preparation with a network side device of a target cell (hereinafter referred to as the target cell, such as a satellite providing services to the target cell).

[0063] In step 113, the terminal determines a TA compensation value according to the TA compensation auxiliary information. In some embodiments, the terminal determines corresponding compensation parameters according to the ephemeris information and the feeder link TA compensation information, respectively, and then determines the TA compensation value in combination with the parameters of the terminal calculating the TA compensation value in the related art, thereby achieving adaptation to the NTN scenario and improving compatibility.

[0064] In some embodiments, the terminal determines the feeder circuit TA compensation value N according to the feeder link TA compensation information and the terminal's own positioning. TA,common , and determine the TA compensation value N of the specific user equipment according to the ephemeris information TA,UE-specific Furthermore, the terminal determines a TA compensation value according to the TA compensation value of the feeding circuit and the TA compensation value of the specific user equipment.

[0065] In some embodiments, the terminal can also determine the TA compensation measurement value N TA In the related art, TA compensation measurement value N TA It is carried in the TAC (Timing Advance Command) sent by the base station to the UE through the MAC CE. During the communication process with the source cell, the terminal obtains the N TA , and then in the current step 113, it is determined whether the satellites corresponding to the target cell and the source cell are the same. If the target cell and the source cell are cells served by the same satellite, then the N distance between the terminal and the target cell is determined. TA and the source cell's N TA Same, the terminal uses the same N as the target cell TACalculate the current TA compensation value. In some embodiments, if the target cell and the source cell are cells served by different satellites, it is not appropriate to continue to use the N value of the source cell. TA , can be compared with the target cell's N TA is set to a predetermined value. In some embodiments, the predetermined value is 0. By this method, it is possible to consider whether the satellites corresponding to the cells are the same, and then determine the corresponding N TA , thereby increasing N TA The exact probability of .

[0066] In some embodiments, the terminal compensates the feed circuit TA according to the value N TA,common and the specific user equipment TA compensation value N TA,UE-specific , combined with TA compensation measurement value N TA ,TA offset N TA,offset and unit time length T c , determine the TA compensation value T TA In some embodiments, the TA compensation value T can be determined based on the following formula: TA .

[0067] T TA =(N TA +N TA,UE-specific +N TA,commin +N TA,offset )×T c (1)

[0068] In the above formula, N TA,offset For fixed offsets of different frequency bands and subcarriers, T c is the unit time length of the system.

[0069] In step 115, the terminal sends initial access information to the NTN based on the TA compensation value.

[0070] Based on the method in the embodiment shown above, when the network side device of the NTN source cell sends a RACH-less switching instruction to the terminal, it can provide auxiliary information that enables the terminal to calculate the TA compensation value applicable to the NTN. The terminal can autonomously calculate the TA compensation value in a timely manner based on the current technology and in combination with the auxiliary information to perform RACH-less switching, thereby simplifying the communication process of the NTN terminal switching, overcoming the delay effect caused by the satellite service link and the feeder link, reducing the probability of switching failure, and improving the switching efficiency.

[0071] In some embodiments, in the above step 115, the wireless resources called by the terminal to send the initial access information to the NTN based on the TA compensation value can be pre-configured. In some embodiments, in the above step 111, the source cell can send the time-frequency resource configuration information to the terminal along with the RACH-less switching instruction, and the terminal parses the time-frequency resource configuration information and stores it for use in step 115. In some embodiments, the source cell can also send the pre-allocated time-frequency resource configuration information to the terminal in advance through RRC information, and the terminal parses the time-frequency resource configuration information and stores it for use in step 115. In some embodiments, the pre-configured time-frequency resource configuration information can have a valid time, which is determined by the source cell according to the ephemeris information and demand. The terminal needs to execute step 115 within the valid time.

[0072] Through this method, resources can be pre-allocated before switching occurs, avoiding the probability of conflicts between multiple users and solving the problem of frequent conflicts caused by terminal switching in NTN cells.

[0073] In some embodiments, in the above step 115, the terminal sends the initial access information to the NTN based on the TA compensation value. The wireless resources called by the terminal can be configured in real time. In some embodiments, the terminal receives the dynamic authorization information of the target cell through DCI. In some embodiments, the DCI can be sent by the source cell to the terminal. After the source cell obtains the dynamic authorization information of the terminal from the target cell, the dynamic authorization information is sent to the terminal through DCI. After receiving the dynamic authorization information, the terminal immediately sends the initial access information to the NTN based on the dynamic authorization information and the TA compensation value calculated in step 113.

[0074] Through this method, the terminal can be triggered by DCI to immediately initiate a RACH-less process, which is more suitable for scenarios with highly changing environments.

[0075] In some embodiments, the terminal switching method further includes step 117, the terminal receives access confirmation information, and the terminal determines that the access is successful according to the access confirmation information. In some embodiments, the access confirmation information may be information sent by the target cell through the link layer control element MAC CE after confirming the terminal access, and the terminal determines that the access is successful according to the information. In some embodiments, the operation of sending the access confirmation information through the MAC CE may be skipped, and the target cell sends downlink data through the physical downlink control channel or physical downlink shared channel PDCCH / PDSCH scrambled by the cell radio network temporary identifier C-RNTI. When the terminal receives the PDCCH / PDSCH downlink data scrambled by the C-RNTI, it determines that the access is successful.

[0076] Through this method, after the RACH-less switching is successful, if the network has terminal downlink data to send, it is not necessary to send a MAC CE message of successful access, but directly send the C-RNTI-scrambled PDCCH / PDSCH, thereby reducing signaling interaction and improving the real-time performance of data transmission.

[0077] Flow charts of other embodiments of the terminal switching method disclosed in the present invention are as follows Figure 2 shown. Figure 2 The method in the illustrated embodiment is performed by a network-side device of NTN, such as a satellite. In some embodiments, the network-side device of NTN can be used as a network-side device on the source cell side of the terminal handover, or as a network-side device on the target cell side of the terminal handover. In some embodiments, when the network-side device of NTN is used as a network-side device on the source cell side, the following can be performed: Figure 2 The method in the illustrated embodiment.

[0078] In step 221, the network side device of the NTN sends handover preparation information to the target cell to which the terminal is handed over. In some embodiments, the network side device of the NTN serving cell of the terminal may determine that the terminal needs to be handed over to another cell based on information such as the signal strength, quality, and location of the terminal, and then determine the target cell for the terminal as a source cell, and interact with the network side device of the target cell. In some embodiments, the information interacted with the network side device of the target cell may include relevant information of the terminal.

[0079] In step 223, the network side device of the NTN sends a RACH-less switching instruction to the terminal, and the TA compensation auxiliary information is included in the random access channel switching instruction. In some embodiments, the TA compensation auxiliary information includes ephemeris information and feeder link TA compensation information, so that the terminal can obtain parameters for implementing TA compensation of the NTN and improve access efficiency.

[0080] In some embodiments, the non-random access channel switching instruction also includes time-frequency resource configuration information pre-allocated to the terminal. Through this method, resources can be pre-allocated in advance before the switching occurs, avoiding the probability of conflicts between multiple users and solving the problem of frequent terminal switching in NTN cells that easily causes conflicts.

[0081] Through the method in the embodiment shown above, when the network side device of the NTN source cell sends a RACH-less switching instruction to the terminal, it can provide auxiliary information that enables the terminal to calculate the TA compensation value applicable to the NTN, so that the terminal can calculate the TA compensation value autonomously in time in combination with the auxiliary information and perform RACH-less switching, thereby simplifying the communication process of the NTN terminal switching, overcoming the delay effect caused by the satellite service link and the feeder link, reducing the probability of switching failure, and improving the switching efficiency.

[0082] In some embodiments, the network side equipment of the source cell can also send pre-allocated time-frequency resource configuration information to the terminal through RRC in advance. The terminal parses the time-frequency resource configuration information and stores it for use when the terminal sends initial access information to the target cell, thereby realizing resource pre-allocation, avoiding the probability of conflicts between multiple users, and solving the problem of frequent terminal switching in NTN cells that easily causes conflicts.

[0083] In some embodiments, the network side equipment of the source cell can receive the dynamic authorization information provided by the target cell and send the dynamic authorization information to the terminal through DCI. After receiving the dynamic authorization information, the terminal immediately sends initial access information to the NTN based on the dynamic authorization information and the calculated TA compensation value.

[0084] Through this method, the terminal can be triggered by DCI to immediately initiate a RACH-less process, which is more suitable for scenarios with highly changing environments.

[0085] Flow charts of some other embodiments of the terminal switching method disclosed in the present invention are as follows: Figure 3 shown. Figure 3 The method in the illustrated embodiment is performed by a network-side device of the NTN, such as a satellite. In some embodiments, the network-side device of the NTN can be used as a network-side device on the source cell side of the terminal switching, or as a network-side device on the target cell side of the terminal switching. In some embodiments, when the network-side device of the NTN is used as a network-side device on the target cell side, the following can be performed: Figure 2 The method in the illustrated embodiment.

[0086] In step 331, the network side equipment of the NTN obtains the switching preparation information from the source cell to which the terminal is switching. In some embodiments, after determining that the terminal needs to switch and selecting the target cell, the network side equipment of the source cell sends the switching preparation information to the network side equipment of the target cell. The network side equipment of the target cell receives the switching preparation information. In some embodiments, the network side equipment of the target cell can determine whether to allow the terminal to switch and provide feedback information. In some embodiments, if the terminal is allowed to switch to this cell, feedback is given to the network side equipment of the source cell so that the network side equipment of the source cell performs the above step 223.

[0087] In step 333, the network side device obtains the initial access information of the terminal. In some embodiments, the terminal may perform the following steps: Figure 1 According to the method in the embodiment, initial access information is sent.

[0088] In some embodiments, the wireless resources on which the initial access information is based can be pre-configured to the terminal based on the method in any of the embodiments shown above. In some embodiments, after the network side device of the target cell determines in the above step 331 that the terminal is allowed to switch to the cell, it can generate dynamic authorization information of the terminal and send the dynamic authorization information to the source cell, which is provided to the terminal by the source cell, and the terminal sends the initial access information based on the dynamic authorization information.

[0089] In step 335, the network side device of the NTN target cell may send access confirmation information to the terminal through MAC CE after the above step 333, so that the terminal can be informed of the success of the handover in time.

[0090] In some embodiments, when there is a need for downlink data transmission, the network side device of the NTN target cell can skip the step of sending access confirmation information to the terminal and directly send downlink data to the terminal through the PDCCH / PDSCH encrypted by the C-RNTI.

[0091] Through this method, after the RACH-less switching is successful, if the network has terminal downlink data to send, it is not necessary to send a MAC CE message of successful access, but directly send the C-RNTI-scrambled PDCCH / PDSCH, thereby reducing signaling interaction and improving the real-time performance of data transmission.

[0092] The signaling flow chart of some embodiments of the terminal switching method disclosed in the present invention is as follows: Figure 4 shown.

[0093] In steps 401-402, the source cell 42 of the NTN network performs a handover decision for the terminal 41, and when it is determined that a cell handover needs to be performed on the terminal 41, a target cell 43 is determined, and handover preparation is performed with the target cell 43. When the target cell 43 determines that it can accept the terminal 41, step 403 is performed.

[0094] In step 403, the source cell 42 issues a RACH-less switching instruction instructing the terminal to perform RACH-less switching, and the instruction includes TA compensation auxiliary information, such as ephemeris information of the target satellite and feeder link TA compensation information. In some embodiments, the RACH-less switching instruction may also include pre-configured time-frequency resource configuration information for the terminal to switch to the target cell.

[0095] In some embodiments, the source cell 42 may send the time-frequency resource configuration information to the terminal at any time before the following step 405 (including a time earlier than before sending the RACH-less switching instruction).

[0096] In some embodiments, the source cell needs to specify the validity period of the time-frequency resource configuration information in combination with the ephemeris and the network needs, and the terminal sends the initial access message within the validity period.

[0097] In step 404, the terminal 41 calculates the final TA compensation value T according to its own location information, the target cell ephemeris information and the feeder link TA compensation value. TA In some embodiments, the calculation method may be as shown in formula (1) above.

[0098] In some embodiments, if the satellite corresponding to the target cell is the same as the source cell, N TA The value is the same as the original cell. If the satellite corresponding to the target cell is different from the source cell, N TA The value is a predetermined value, such as 0. The terminal 41 can calculate N according to the terminal position and ephemeris information. TA,UE-specific ; According to the feeder link TA compensation value, N can be obtained TA,common .

[0099] In step 405, the terminal 41 sends an initial access message to the target cell 43 based on the TA compensation value. In some embodiments, the initial access message may be sent by multiplexing an RRCReconfigurationComplete message.

[0100] In step 406, the target cell 43 sends an access confirmation message to the terminal after receiving the RRCReconfigurationComplete message. In some embodiments, the confirmation message may be a MAC CE, indicating that the RACH-less handover of the terminal is successful; if the target cell 43 has downlink data to be sent to the terminal 41, it may directly send a C-RNTI-scrambled PDCCH / PDSCH and skip the step of sending a MAC CE confirmation message.

[0101] Through the method in the embodiment shown above, the source cell can send TA compensation auxiliary information to the terminal. Combining this information with its own location information, the terminal can compensate for the TA value by itself, thereby overcoming the delay effect caused by the satellite service link and the feeder link; providing time-frequency resource configuration information to the terminal in a pre-configured manner, and indicating the effective time corresponding to the time-frequency resource configuration information, can avoid the probability of conflicts between multiple users; after the RACH-less switching is successful, if the network has terminal downlink data to send, it is not necessary to send a MAC CE message of successful access, and directly send a C-RNTI-encrypted PDCCH / PDSCH, thereby reducing signaling interaction and improving the real-time performance of data transmission.

[0102] The signaling flow charts of other embodiments of the terminal switching method disclosed in the present invention are as follows: Figure 5 shown.

[0103] Steps 501 and 502 are similar to the above-mentioned steps 401 and 402 respectively.

[0104] In step 503, the source cell 52 issues a RACH-less switching instruction instructing the terminal to perform RACH-less switching, and the instruction includes TA compensation auxiliary information, such as ephemeris information of the target satellite and feeder link TA compensation information.

[0105] In step 504, the terminal 51 calculates the final TA compensation value T according to its own location information, the target cell ephemeris information and the feeder link TA compensation value. TA In some embodiments, the calculation method may be as shown in formula (1) above.

[0106] In some embodiments, if the satellite corresponding to the target cell is the same as the source cell, N TA The value is the same as the original cell. If the satellite corresponding to the target cell is different from the source cell, N TA The value is a predetermined value, such as 0. The terminal 51 can calculate N according to the terminal position and ephemeris information. TA,UE-specific ; According to the feeder link TA compensation value, N can be obtained TA,common .

[0107] In step 505 , the target cell 53 performs uplink authorization for the terminal 51 , and sends dynamic authorization information to the terminal 51 via the source cell 52 through DCI.

[0108] In step 506, after receiving the dynamic authorization information, the terminal 51 immediately sends an initial access message to the network side based on the TA compensation value obtained in step 503. In some embodiments, the initial access message may be multiplexed with an RRCReconfigurationComplete message.

[0109] In step 507, the target cell 53 sends an access confirmation message to the terminal after receiving the RRCReconfigurationComplete message. In some embodiments, the confirmation message may be a MAC CE, indicating that the RACH-less handover of the terminal is successful; if the target cell 53 has downlink data to be sent to the terminal 51, it may directly send a C-RNTI-scrambled PDCCH / PDSCH and skip the step of sending a MAC CE confirmation message.

[0110] Through the method in the embodiment shown above, the source cell can send TA compensation auxiliary information to the terminal. Combining this information with its own location information, the terminal can compensate the TA value by itself, thereby overcoming the delay effect caused by the satellite service link and the feeder link; dynamic authorization information is provided to the terminal through DCI so that the terminal can send initial access information, which is suitable for scenarios with highly changing environments; after the RACH-less switching is successful, if the network has terminal downlink data to send, it is not necessary to send a MAC CE message of successful access, and directly send the C-RNTI-scrambled PDCCH / PDSCH, thereby reducing signaling interaction and improving the real-time performance of data transmission.

[0111] Schematic diagrams of some embodiments of the terminal disclosed in the present invention are as follows Figure 6 In some embodiments, the terminal is a terminal for which wireless access service is provided by NTN, or a terminal that supports obtaining network service capability through NTN.

[0112] The information acquisition unit 611 can receive a RACH-less switching instruction from a source cell of the NTN, and the RACH-less switching instruction includes TA compensation auxiliary information. In some embodiments, the TA compensation auxiliary information is information required by the terminal to calculate the TA compensation value. In some embodiments, the TA compensation auxiliary information includes ephemeris information and feeder link TA compensation information, so that the terminal can obtain parameters for implementing TA compensation of the NTN and improve access efficiency. In some embodiments, the ephemeris information in the auxiliary information is the ephemeris information of the target cell.

[0113] The compensation value determination unit 612 can determine the TA compensation value according to the TA compensation auxiliary information. In some embodiments, the terminal determines the corresponding compensation parameters according to the ephemeris information and the feeder link TA compensation information, and then determines the TA compensation value in combination with the parameters of the terminal calculating the TA compensation value in the related art, thereby achieving adaptation to the NTN scenario and improving compatibility. In some embodiments, the compensation value determination unit 612 can determine the TA compensation value based on the method in any embodiment of step 113 above.

[0114] The access unit 613 can send initial access information to the target cell of the NTN based on the TA compensation value.

[0115] Such a terminal can use the RACH-less switching instruction to obtain auxiliary information for calculating the TA compensation value suitable for NTN, and can timely and autonomously calculate the TA compensation value in combination with the auxiliary information to perform RACH-less switching, thereby simplifying the communication process of NTN terminal switching, overcoming the delay effect caused by the satellite service link and the feeder link, reducing the probability of switching failure, and improving switching efficiency.

[0116] In some embodiments, the information acquisition unit 611 may also acquire pre-allocated time-frequency resource configuration information and store the time-frequency resource configuration information. In some embodiments, the time-frequency resource configuration information may be acquired with a RACH-less switching instruction or acquired through RRC information. In some embodiments, the access unit 613 may send initial access information to the NTN based on the TA compensation value after the compensation value determination unit 612 determines the TA compensation value, according to the stored time-frequency resource configuration information.

[0117] Such a terminal can pre-allocate resources before switching occurs, avoiding the probability of conflicts between multiple users and solving the problem of frequent conflicts caused by terminal switching in NTN cells.

[0118] In some embodiments, the information acquisition unit 611 can receive the dynamic authorization information of the target cell through the downlink control information. After receiving the dynamic authorization information, the access unit 613 can send the initial access information to the NTN based on the TA compensation value according to the dynamic authorization information. Such a terminal can immediately initiate the RACH-less process through the DCI trigger terminal, which is more suitable for scenarios with highly changing environments.

[0119] In some embodiments, the information acquisition unit 611 can also receive access confirmation information, wherein the terminal determines that the access is successful according to the access confirmation information. In some embodiments, the information acquisition unit 611 can also obtain downlink data through the PDCCH or PDSCH scrambled by the C-RNTI, and the terminal does not need to receive separate access success information, and determines that the access is successful according to the received downlink data. Such a terminal can improve the real-time performance of data transmission while reducing signaling interaction.

[0120] Schematic diagrams of some embodiments of the NTN network side equipment disclosed in the present invention are as follows Figure 7 shown.

[0121] The handover preparation interaction unit 721 can send handover preparation information to the target cell to which the terminal is switched. In some embodiments, the network side device of the service cell NTN of the terminal can determine that the terminal needs to be switched to another cell based on information such as the signal strength, quality, and location of the terminal, and the handover preparation interaction unit 721 interacts with the network side device of the target cell. In some embodiments, the interactive information may include relevant information of the terminal.

[0122] The information sending unit 722 can send a RACH-less switching instruction to the terminal, and the TA compensation auxiliary information is included in the random access channel switching instruction. In some embodiments, the TA compensation auxiliary information includes ephemeris information and feeder link TA compensation information, so that the terminal can obtain parameters for implementing NTN TA compensation and improve access efficiency.

[0123] In some embodiments, the non-random access channel switching instruction also includes time-frequency resource configuration information pre-allocated to the terminal, so that resources can be pre-allocated in advance before the switching occurs, avoiding the probability of conflicts between multiple users and solving the problem of frequent terminal switching in NTN cells that easily causes conflicts.

[0124] When such a network-side device sends a RACH-less switching instruction to the terminal, it can provide auxiliary information for the terminal to calculate the TA compensation value suitable for NTN, so that the terminal can automatically calculate the TA compensation value in a timely manner based on the auxiliary information and perform RACH-less switching, thereby simplifying the communication process of NTN terminal switching, overcoming the delay effect caused by the satellite service link and the feeder link, reducing the probability of switching failure, and improving switching efficiency.

[0125] In some embodiments, the information sending unit 722 can also send pre-allocated time-frequency resource configuration information to the terminal through wireless resource control information. The terminal parses the time-frequency resource configuration information and stores it for use when the terminal sends initial access information to the target cell, thereby realizing resource pre-allocation, avoiding the probability of conflicts between multiple users, and solving the problem of frequent terminal switching in NTN cells that easily causes conflicts.

[0126] In some embodiments, the handover preparation interaction unit 721 can also receive dynamic authorization information from the target cell. The information sending unit 722 can also send the dynamic authorization information to the terminal through downlink control information. After receiving the dynamic authorization information, the terminal immediately sends initial access information to the NTN based on the dynamic authorization information and the calculated TA compensation value.

[0127] Such network-side equipment can trigger the terminal to immediately initiate a RACH-less process through DCI, which is more suitable for scenarios with highly changing environments.

[0128] Schematic diagrams of other embodiments of the NTN network side device disclosed in the present invention are as follows Figure 8 shown.

[0129] The handover preparation unit 831 can obtain handover preparation information from the source cell of the terminal handover. In some embodiments, after determining that the terminal needs to be handed over and selecting the target cell, the network side device of the source cell sends handover preparation information to the network side device of the target cell. The handover preparation unit 831 receives the handover preparation information. In some embodiments, the handover preparation unit 831 can determine whether the terminal is allowed to handover and provide feedback information. In some embodiments, if the terminal is allowed to switch to this cell, the handover preparation unit 831 feeds back to the network side device of the source cell so that the network side device of the source cell performs the above step 223.

[0130] In some embodiments, after the switching preparation unit 831 determines that the terminal is allowed to switch to the current cell, it can generate dynamic authorization information of the terminal and send the dynamic authorization information to the source cell, which provides it to the terminal. The terminal sends initial access information based on the dynamic authorization information.

[0131] The access information receiving unit 832 can obtain the initial access information of the terminal. In some embodiments, the wireless resources based on the initial access information can be pre-configured to the terminal based on the method in any of the embodiments shown above.

[0132] The access confirmation unit 833 can send downlink data via a PDCCH or PDSCH scrambled by the C-RNTI. In some embodiments, the access confirmation unit can also send access confirmation information to the terminal. In some embodiments, when there is a downlink data transmission requirement, the network side device of the NTN target cell can skip the step of sending access confirmation information to the terminal.

[0133] Such NTN network-side equipment can implement the RACH-less switching process of NTN terminals, simplify the communication process of NTN terminal switching, overcome the delay impact caused by satellite service links and feeder links, reduce the probability of switching failure, and improve switching efficiency; support direct sending of downlink data to the terminal through PDCCH / PDSCH encrypted by C-RNTI, reduce signaling interaction and improve the real-time performance of data transmission.

[0134] In some embodiments, the network side equipment of NTN can also have the following Figure 7 , Figure 8 The unit in the illustrated embodiment thus has the capability of serving as a network-side device of both a source cell and a target cell, thereby facilitating flexible switching of the terminal between different cells.

[0135] A structural diagram of an embodiment of the network device disclosed in the present invention is shown in FIG. Fig. 9 As shown. The network device includes a memory 901 and a processor 902. Among them: the memory 901 can be a disk, a flash memory or any other non-volatile storage medium. The memory is used to store the instructions in the corresponding embodiment of the terminal switching method mentioned above. The processor 902 is coupled to the memory 901 and can be implemented as one or more integrated circuits, such as a microprocessor or a microcontroller. The processor 902 is used to execute the instructions stored in the memory, which can simplify the communication process of the NTN terminal switching, overcome the delay effect caused by the satellite service link and the feeder link, reduce the probability of switching failure, and improve the switching efficiency.

[0136] In one embodiment, it is also possible to Fig.10As shown, the network device 1000 includes a memory 1001 and a processor 1002. The processor 1002 is coupled to the memory 1001 via a BUS 1003. The network device 1000 can also be connected to an external storage device 1005 via a storage interface 1004 to call external data, and can also be connected to a network or another computer system (not shown) via a network interface 1006. No further detailed description will be given here.

[0137] In this embodiment, by storing data instructions in a memory and then processing the instructions through a processor, the communication process of NTN terminal switching can be simplified, the delay effect caused by the satellite service link and the feeder link can be overcome, the probability of switching failure can be reduced, and the switching efficiency can be improved.

[0138] In another embodiment, a computer-readable storage medium stores thereon computer program instructions, which are executed by a processor to implement the steps of the method in the corresponding embodiment of the terminal switching method. It should be understood by those skilled in the art that the embodiments of the present disclosure can be provided as methods, devices, or computer program products. Therefore, the present disclosure can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer-usable non-transient storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0139] Schematic diagrams of some embodiments of the NTN network side system 1100 of the present disclosure are as follows: Fig.11 shown.

[0140] The first network side device 1120 can execute any of the terminal switching methods mentioned above on the source cell side of the terminal switching.

[0141] The second network side device 1130 can execute any of the terminal switching methods mentioned above on the target cell side of the terminal switching.

[0142] In such an NTN network side system, when the network side device sends a RACH-less switching instruction to the terminal, it can provide auxiliary information that enables the terminal to calculate the TA compensation value suitable for NTN. The terminal can autonomously calculate the TA compensation value in a timely manner based on the current technology and the auxiliary information, and perform RACH-less switching, thereby simplifying the communication process of NTN terminal switching, overcoming the delay effect caused by the satellite service link and the feeder link, reducing the probability of switching failure, and improving switching efficiency.

[0143] In some embodiments, each network side device in the network side system of the NTN may simultaneously have the ability to execute any one of the terminal switching methods on the source cell side of the terminal switching mentioned above, and execute any one of the terminal switching methods on the target cell side of the terminal switching mentioned above, thereby facilitating flexible switching of the terminal between cells.

[0144] Schematic diagrams of some embodiments of the NTN system disclosed in the present invention are as follows Fig.12 shown.

[0145] The terminal 1210 can execute any of the above methods executed by a terminal.

[0146] Network side devices 1221, 1222, wherein at least one network side device (such as source satellite 1221) can execute any one of the terminal switching methods on the source cell side of the terminal switching mentioned above, and at least one network side device (such as target satellite 1222) can execute any one of the terminal switching methods on the target cell side of the terminal switching mentioned above. In some embodiments, each network side device can support at least one cell, and the network side device can simultaneously support the devices as the source cell and the target cell to execute the terminal switching method.

[0147] In such an NTN system, when the network-side device sends a RACH-less switching instruction to the terminal, it can provide auxiliary information that enables the terminal to calculate the TA compensation value suitable for NTN. The terminal can autonomously calculate the TA compensation value in a timely manner based on the current technology and the auxiliary information, and perform RACH-less switching, thereby simplifying the communication process of NTN terminal switching, overcoming the delay effect caused by the satellite service link and the feeder link, reducing the probability of switching failure, and improving switching efficiency.

[0148] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0149] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0150] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0151] So far, the present disclosure has been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0152] The method and apparatus of the present disclosure may be implemented in many ways. For example, the method and apparatus of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present disclosure may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present disclosure. Therefore, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0153] It should be noted that the terms "first", "second", etc. in the specification, claims, and drawings of the present disclosure are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present disclosure rather than to limit it. Although the present disclosure has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present disclosure can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present disclosure, which should be included in the scope of the technical solution for protection of the present disclosure.

Claims

1. A terminal switching method, comprising: A terminal located in a non-terrestrial network receives a non-random access channel switching instruction, wherein the non-random access channel switching instruction includes timing advance compensation auxiliary information; The terminal determines a timing advance compensation value according to the timing advance compensation auxiliary information; The terminal sends initial access information to the non-terrestrial network based on the timing advance compensation value.

2. The terminal switching method according to claim 1, wherein: The timing advance compensation auxiliary information includes ephemeris information.

3. The terminal switching method according to claim 2, wherein: The timing advance compensation auxiliary information also includes feeder link TA compensation information.

4. The terminal switching method according to claim 1, wherein: The non-random access channel switching instruction also includes pre-allocated time-frequency resource configuration information, The terminal switching method further includes: the terminal storing the time-frequency resource configuration information.

5. The terminal switching method according to claim 1, further comprising: The terminal obtains and stores the pre-allocated time-frequency resource configuration information through the radio resource control information.

6. The terminal switching method according to claim 4 or 5, wherein: The terminal sending initial access information to the non-terrestrial network based on the timing advance compensation value includes: After the terminal determines the timing advance compensation value, the terminal sends initial access information to the non-terrestrial network based on the timing advance compensation value according to the stored time-frequency resource configuration information.

7. The terminal switching method according to claim 1, further comprising: The terminal receives dynamic authorization information of the target cell through downlink control information; The terminal sending initial access information to the non-terrestrial network based on the timing advance compensation value includes: After receiving the dynamic authorization information, the terminal sends initial access information to the non-terrestrial network based on the timing advance compensation value according to the dynamic authorization information.

8. The terminal switching method according to claim 3, wherein: The terminal determining the timing advance compensation value according to the timing advance compensation auxiliary information includes: Determining a feeder circuit timing advance compensation value according to the feeder link timing advance compensation information; determining a timing advance compensation value for a specific user equipment according to the ephemeris information; The timing advance compensation value is determined according to the feeding circuit timing advance compensation value and the specific user equipment timing advance compensation value.

9. The terminal switching method according to claim 8, wherein: The terminal determining the timing advance compensation value according to the timing advance compensation auxiliary information further includes: the terminal determining a timing advance compensation measurement value.

10. The terminal switching method according to claim 9, wherein: The determining the timing advance compensation value according to the feeder circuit timing advance compensation value and the specific user equipment timing advance compensation value comprises: The timing advance compensation value is determined according to the timing advance compensation value of the feeder circuit and the timing advance compensation value of the specific user equipment, in combination with the timing advance compensation measurement value, the timing advance offset and the unit time length.

11. The terminal switching method according to claim 9, wherein: The determining of the timing advance compensation measurement value includes: when the source cell and the target cell correspond to the same satellite, the timing advance compensation measurement value is the same as the source cell.

12. The terminal switching method according to claim 9, wherein: The determining of the timing advance compensation measurement value includes: when the source cell and the target cell correspond to different satellites, the timing advance compensation measurement value is a predetermined value.

13. The terminal switching method according to claim 1, further comprising: The terminal receives access confirmation information, and the terminal determines that the access is successful according to the access confirmation information.

14. The terminal switching method according to claim 13, wherein: The access confirmation information is carried by a link layer control element.

15. The terminal switching method according to claim 1, further comprising: The terminal obtains downlink data through a physical downlink control channel or a physical downlink shared channel scrambled by a cell radio network temporary identifier, wherein the terminal determines that access is successful according to the downlink data.

16. A terminal switching method, comprising: The network side device of the non-terrestrial network sends handover preparation information to the target cell for handover of the terminal; The network side device sends a non-random access channel switching instruction, where the non-random access channel switching instruction includes timing advance compensation auxiliary information.

17. The terminal switching method according to claim 16, wherein: The non-random access channel switching instruction also includes time-frequency resource configuration information pre-allocated to the terminal.

18. The terminal switching method according to claim 16, further comprising: The pre-allocated time-frequency resource configuration information is sent to the terminal via radio resource control information.

19. The terminal switching method according to claim 16, further comprising: receiving dynamic authorization information from the target cell; The dynamic authorization information is sent to the terminal via downlink control information.

20. A terminal switching method, comprising: The network side equipment of the non-terrestrial network obtains the handover preparation information from the source cell of the terminal handover; The network side device obtains initial access information of the terminal; Downlink data is sent through a physical downlink control channel or a physical downlink shared channel scrambled by a cell radio network temporary identifier.

21. The terminal switching method according to claim 20, further comprising: Send access confirmation information to the terminal.

22. The terminal switching method according to claim 21, wherein: The access confirmation information is carried by a link layer control element.

23. The terminal switching method according to claim 20, further comprising: After receiving the switching preparation information, the network side device generates dynamic authorization information of the terminal; The dynamic authorization information is sent to the source cell.

24. A terminal, comprising: An information acquisition unit is configured to receive a non-random access channel switching instruction from a source cell of a non-terrestrial network, wherein the non-random access channel switching instruction includes timing advance compensation auxiliary information; a compensation value determining unit, configured to determine a timing advance compensation value according to the timing advance compensation auxiliary information; An access unit is configured to send initial access information to a target cell of the non-terrestrial network based on the timing advance compensation value.

25. The terminal according to claim 24, wherein: The timing advance compensation auxiliary information includes ephemeris information and feeder link timing advance compensation information.

26. The terminal according to claim 24, wherein: The non-random access channel switching instruction also includes pre-allocated time-frequency resource configuration information, The information acquisition unit is further configured to store the time-frequency resource configuration information.

27. The terminal according to claim 24, wherein: The information acquisition unit is further configured to acquire and store the pre-allocated time-frequency resource configuration information through the radio resource control information.

28. The terminal according to claim 26 or 27, wherein: The access unit is configured to send initial access information to the non-terrestrial network based on the timing advance compensation value according to the stored time-frequency resource configuration information after the compensation value determination unit determines the timing advance compensation value.

29. The terminal according to claim 24, wherein: The information acquisition unit is further configured to receive dynamic authorization information of the target cell through downlink control information; The access unit is configured to, after receiving the dynamic grant information, send initial access information to the non-terrestrial network based on the timing advance compensation value according to the dynamic grant information.

30. The terminal according to claim 24, wherein: The information acquisition unit is further configured to perform at least one of the following: receiving access confirmation information, wherein the terminal determines that the access is successful according to the access confirmation information; or The downlink data is obtained through a physical downlink control channel or a physical downlink shared channel scrambled by a cell radio network temporary identifier, wherein the terminal determines that the access is successful according to the downlink data.

31. A network side device of a non-terrestrial network, comprising: A handover preparation interaction unit, configured to send handover preparation information to a target cell for handover of the terminal; The information sending unit is configured to send a non-random access channel switching instruction, wherein the non-random access channel switching instruction includes timing advance compensation auxiliary information.

32. The network side device according to claim 31, wherein: The non-random access channel switching instruction also includes time-frequency resource configuration information pre-allocated to the terminal.

33. The network side device according to claim 31, wherein: The information sending unit is further configured to send pre-allocated time-frequency resource configuration information to the terminal via radio resource control information.

34. The network side device according to claim 31, wherein: The handover preparation interaction unit is further configured to receive dynamic authorization information from the target cell; The information sending unit is further configured to send the dynamic authorization information to the terminal via downlink control information.

35. A network side device of a non-terrestrial network, comprising: A handover preparation unit, configured to obtain handover preparation information from a source cell of a handover of a terminal; An access information receiving unit, configured to obtain initial access information of a terminal; The access confirmation unit is configured to send downlink data through a physical downlink control channel or a physical downlink shared channel scrambled by a cell radio network temporary identifier.

36. The network side device according to claim 35, wherein: The access confirmation unit is further configured to send access confirmation information to the terminal.

37. The network side device according to claim 35, wherein: The handover preparation unit is further configured to generate dynamic authorization information of the terminal after receiving the handover preparation information, and send the dynamic authorization information to the source cell.

38. A network device comprising: Memory; as well as A processor coupled to the memory, the processor being configured to execute the method according to any one of claims 1 to 23 based on instructions stored in the memory.

39. A computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, implement the steps of the method described in any one of claims 1 to 23.

40. A network side system of a non-terrestrial network, comprising: A first network side device, configured to execute the method according to any one of claims 16 to 19; and The second network side device is configured to execute the method described in any one of claims 20 to 23.

41. A non-terrestrial network system, comprising: A terminal, configured to execute the method according to any one of claims 1 to 15; and Network side device, wherein at least one network side device is configured to execute the method described in any one of claims 16 to 19; and at least one network side device is configured to execute the method described in any one of claims 20 to 23.

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