Synchronization method and terminal, access network device, communication system and storage medium

Abstract

The embodiment of the invention provides a synchronization method, a terminal, access network equipment, a communication system and a storage medium. The method is executed by a terminal, and the method comprises the following steps: the terminal keeps synchronization with a first cell according to first information; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following contents: a synchronization signal broadcast channel block SSB; one or more system information blocks (SIBs); and paging the message. According to the technical scheme provided by the embodiment of the invention, the time-frequency synchronization of the terminal and the first cell is ensured under the condition of realizing network energy conservation, and the normal mobility of the terminal is ensured.

Description

Synchronization method and terminal, access network equipment, communication system and storage medium Technical Field

[0001] The present disclosure relates to the field of communication technology, and in particular to a synchronization method and terminal, access network equipment, a communication system, and a storage medium. Background Art

[0002] With people's pursuit of communication speed, latency, high-speed mobility, energy efficiency, and the diversity and complexity of services, the fifth generation of mobile communication (5G) technology has come into being. The application scenarios of 5G technology mainly include: Enhanced Mobile Broadband (eMBB), Low Latency and High Reliability Communication (URLLC), and Massive Machine Type Communication (mMTC).

[0003] However, the energy consumption of 5G base stations is relatively high. How to achieve network energy saving and reduce the operating costs of 5G systems?

[0004] Summary of the Invention

[0005] With the development of low-energy access network equipment, the time and frequency synchronization between the terminal and the low-energy access network equipment is ensured.

[0006] Embodiments of the present disclosure provide a synchronization method and terminal, access network equipment, a communication system, and a storage medium.

[0007] According to a first aspect of an embodiment of the present disclosure, a synchronization method is provided, wherein the method includes:

[0008] The terminal maintains synchronization with a first cell according to the first information; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0009] Synchronization and PBCHsignal Block (SSB);

[0010] One or more System Information Blocks (SIBs);

[0011] Paging message.

[0012] According to a second aspect of an embodiment of the present disclosure, a synchronization method is provided, wherein the method includes:

[0013] A first cell sends first information; the first information is used for the terminal to maintain synchronization with the first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0014] Synchronization signal broadcast channel block SSB;

[0015] One or more system information blocks (SIBs);

[0016] Paging message.

[0017] According to a third aspect of an embodiment of the present disclosure, a synchronization method is provided, wherein the method includes:

[0018] The second cell sends first information to the terminal; the first information is used for the terminal to maintain synchronization with the first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0019] Synchronization signal broadcast channel block SSB;

[0020] One or more system information blocks (SIBs);

[0021] Paging message.

[0022] According to a fourth aspect of an embodiment of the present disclosure, a synchronization method is provided, wherein the method includes:

[0023] The third cell obtains first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal; wherein the first cell does not send one or more of the following:

[0024] Synchronization signal broadcast channel block SSB;

[0025] One or more system information blocks (SIBs);

[0026] Paging message.

[0027] According to a fifth aspect of an embodiment of the present disclosure, a synchronization method is provided, wherein the method includes:

[0028] Before the terminal switches to the first cell, the third cell obtains first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal;

[0029] After the terminal switches to the first cell, the first cell and / or the second cell sends first information;

[0030] The terminal maintains synchronization with the first cell according to the first information; the first cell does not send one or more of the following:

[0031] Synchronization signal broadcast channel block SSB;

[0032] One or more system information blocks (SIBs);

[0033] Paging message.

[0034] According to a sixth aspect of an embodiment of the present disclosure, a terminal is provided, wherein the terminal includes:

[0035] The processing module is configured to maintain synchronization with a first cell according to the first information; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0036] Synchronization signal broadcast channel block SSB;

[0037] One or more system information blocks (SIBs);

[0038] Paging message.

[0039] According to a seventh aspect of an embodiment of the present disclosure, a first access network device is provided, wherein the first access network device includes:

[0040] The first transceiver module is configured to send first information; the first information is used for the terminal to maintain synchronization with a first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0041] Synchronization signal broadcast channel block SSB;

[0042] One or more system information blocks (SIBs);

[0043] Paging message.

[0044] According to an eighth aspect of an embodiment of the present disclosure, a second access network device is provided, wherein the second access network device includes:

[0045] The second transceiver module is configured to send first information, wherein the first information is used for the terminal to maintain synchronization with a first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0046] Synchronization signal broadcast channel block SSB;

[0047] One or more system information blocks (SIBs);

[0048] Paging message.

[0049] According to a ninth aspect of an embodiment of the present disclosure, a third access network device is provided, wherein the third access network device includes:

[0050] The third transceiver module is configured to obtain first capability information of the terminal; the first capability information is used to determine whether a first cell can serve as a serving cell for the terminal; wherein the first cell does not send one or more of the following:

[0051] Synchronization signal broadcast channel block SSB;

[0052] One or more system information blocks (SIBs);

[0053] Paging message.

[0054] According to the tenth aspect of an embodiment of the present disclosure, a communication system is provided, wherein the communication system includes a terminal, a first access network device, a second access network device and a third access network device, the terminal is configured to implement the synchronization method provided by the first aspect, the first access network device is configured to implement the synchronization method provided by the second aspect, the second access network device is configured to implement the synchronization method provided by the third aspect, and the third access network device is configured to implement the synchronization method provided by the fourth aspect.

[0055] According to an eleventh aspect of the embodiments of the present disclosure, a communication device is provided, wherein the communication device includes:

[0056] one or more processors;

[0057] The processor is used to call instructions to enable the communication device to execute the synchronization method provided by the first aspect, the second aspect, the third aspect or the fourth aspect.

[0058] According to the twelfth aspect of an embodiment of the present disclosure, a storage medium is provided, wherein the storage medium stores instructions, and when the instructions are executed on a communication device, the communication device executes the synchronization method provided by the first aspect, the second aspect, the third aspect or the fourth aspect.

[0059] The technical solution provided by the embodiments of the present disclosure is conducive to ensuring time and frequency synchronization between the terminal and the first cell while achieving network energy saving, and ensuring normal mobility of the terminal.

[0060] It should be understood that the foregoing general description and the following detailed description are merely exemplary and explanatory and are not restrictive of the embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the embodiments of the present invention.

[0062] FIG1 is a schematic diagram showing an architecture of a communication system according to an exemplary embodiment;

[0063] FIG2a is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0064] FIG2 b is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0065] FIG3a is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0066] FIG3 b is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0067] FIG3c is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0068] FIG4a is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0069] FIG4 b is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0070] FIG4c is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0071] FIG4 d is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0072] FIG4e is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0073] FIG4f is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0074] FIG5 is a schematic flow chart showing a synchronization method according to an exemplary embodiment;

[0075] FIG6 is a schematic diagram showing a different type of cell broadcast configuration according to an embodiment of the present disclosure;

[0076] FIG7a is a schematic structural diagram of a terminal according to an exemplary embodiment;

[0077] FIG7b is a schematic structural diagram of a first access network device according to an exemplary embodiment;

[0078] FIG7c is a schematic structural diagram of a second access network device according to an exemplary embodiment;

[0079] FIG7 d is a schematic structural diagram of a third access network device according to an exemplary embodiment;

[0080] FIG8a is a schematic structural diagram of a UE according to an exemplary embodiment;

[0081] Fig. 8b is a schematic structural diagram of a communication device according to an exemplary embodiment. DETAILED DESCRIPTION

[0082] Embodiments of the present disclosure provide a synchronization method and terminal, access network equipment, a communication system, and a storage medium.

[0083] In a first aspect, an embodiment of the present disclosure provides a synchronization method, wherein the method includes:

[0084] The terminal maintains synchronization with a first cell according to the first information; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0085] Synchronization signal broadcast channel block SSB;

[0086] One or more system information blocks (SIBs);

[0087] Paging message.

[0088] In the above embodiment, for the first cell that does not send SSB, SIB and paging messages, after the terminal switches to the first cell, it can maintain synchronization with the first cell based on the first information, thereby ensuring the time and frequency synchronization between the terminal and the first cell while achieving network energy saving, and ensuring the normal mobility of the terminal.

[0089] In conjunction with some embodiments of the first aspect, in some embodiments,

[0090] The first information is determined by a protocol;

[0091] or,

[0092] The first information is sent by the first cell to the terminal;

[0093] Alternatively, the first information is sent to the terminal by a second cell; wherein the second cell is different from the first cell.

[0094] In the above embodiment, the terminal can obtain the first information through the protocol, or by receiving the first information sent by the first cell or the second cell, thereby improving the flexibility of obtaining the first information, so as to utilize the first information to ensure time and frequency synchronization between the terminal and the first cell.

[0095] In conjunction with some embodiments of the first aspect, in some embodiments, the first information includes at least one of the following:

[0096] A first configuration is configured for the terminal to maintain synchronization with the first cell according to a first signal sent by the second cell;

[0097] The control signaling includes: second information used to maintain synchronization between the terminal and the first cell;

[0098] The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

[0099] In the above embodiment, the terminal may maintain synchronization with the first cell by referring to the first signal sent by the second cell, or the second signal sent by the first cell, or directly maintain synchronization with the first cell based on the second information carried in the control signaling, thereby ensuring time and frequency synchronization between the terminal and the first cell while improving synchronization flexibility. In conjunction with some embodiments of the first aspect, in some embodiments, the second signal is also used for radio resource management (RRM) of the terminal.

[0100] In the above embodiment, the second signal sent by the first cell can not only be used for the terminal to maintain synchronization with the first cell, but also be used for radio resource management RRM of the terminal to maintain normal mobility of the terminal.

[0101] In combination with some embodiments of the first aspect, in some embodiments, the first signal includes: a synchronization signal broadcast channel block SSB.

[0102] In the above embodiment, the terminal may refer to the SSB sent by the normal type of the second cell to achieve time and frequency synchronization between the terminal and the first cell.

[0103] In conjunction with some embodiments of the first aspect, in some embodiments, the second signal includes at least one of the following:

[0104] Channel State Information (CSI)-Reference Signal (RS);

[0105] Tracking Reference Signal (TRS);

[0106] A third signal, wherein the third signal is different from the SSB, the CSI-RS and / or the TRS and is a signal used to maintain synchronization between the terminal and the first cell.

[0107] In the above embodiment, the first cell may send a CSI-RS, a TRS, and a third signal for maintaining synchronization, so that the terminal can maintain synchronization with the first cell based on the above signals.

[0108] In combination with some embodiments of the first aspect, in some embodiments, the third signal also carries system frame information.

[0109] In the above embodiment, the terminal may obtain system frame information from the third signal sent by the first cell, and use the system frame information to determine the timing relationship of relevant parameters of the synchronization measurement, so as to maintain synchronization with the first cell.

[0110] In conjunction with some embodiments of the first aspect, in some embodiments, the first configuration includes at least one of the following:

[0111] Measurement period;

[0112] Measurement window;

[0113] Measurement bias;

[0114] cell information of the second cell;

[0115] Timing information is used by the terminal to determine the downlink timing of the first cell.

[0116] In the above embodiment, the terminal may measure the first signal sent by the second cell, which is the synchronization reference cell of the first cell, according to at least one of the above information in the first configuration, so as to maintain synchronization between the terminal and the first cell based on the synchronization measurement result of the first signal.

[0117] In conjunction with some embodiments of the first aspect, in some embodiments, the timing information includes at least one of the following:

[0118] downlink timing information of the second cell;

[0119] The timing offset between the second cell and the first cell.

[0120] In the above embodiment, the terminal may determine the downlink timing information of the first cell based on the downlink timing information of the second cell and / or the timing offset between the second cell and the first cell, so as to maintain synchronization with the first cell.

[0121] In conjunction with some embodiments of the first aspect, in some embodiments, the second configuration includes at least one of the following:

[0122] Measurement period;

[0123] Measurement window;

[0124] Measurement bias;

[0125] Measure the signal.

[0126] In the above embodiment, the terminal may measure the second signal sent by the first cell according to the at least one information in the second configuration, so as to maintain synchronization between the terminal and the first cell based on the synchronization measurement result of the second signal.

[0127] In conjunction with some embodiments of the first aspect, in some embodiments, the first configuration further includes:

[0128] SSB measurement timing (SSB Measurement Timing Configuration, SMTC) configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the second cell.

[0129] In the above embodiment, the first configuration also includes SMTC configuration and / or measurement interval configuration of the first signal, and the SMTC configuration and / or measurement interval configuration of the first signal is determined based on the downlink timing information of the second cell, thereby facilitating the terminal to determine the measurement time of the RRM measurement and the measurement time of the synchronous measurement of the first signal based on the downlink timing information of the second cell.

[0130] In conjunction with some embodiments of the first aspect, in some embodiments, the second configuration further includes:

[0131] SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the first cell.

[0132] In the above embodiment, the first configuration also includes SMTC configuration and / or measurement interval configuration of the second signal, and the SMTC configuration and / or measurement interval configuration of the second signal is determined based on the downlink timing information of the first cell, thereby facilitating the terminal to determine the measurement time of the RRM measurement and the measurement time of the synchronous measurement of the second signal based on the downlink timing information of the first cell.

[0133] With reference to some embodiments of the first aspect, in some embodiments, the control signaling includes:

[0134] Downlink Control Information (DCI).

[0135] In the above embodiment, the second information for maintaining synchronization between the first cell and the terminal may be carried in the downlink control information DCI, thereby directly multiplexing the downlink control information DCI to transmit the second information and reduce signaling overhead.

[0136] In combination with some embodiments of the first aspect, in some embodiments, the second information includes: system frame information.

[0137] In the above embodiment, the downlink control information DCI may directly carry the system frame information, so that the terminal can determine relevant measurement parameters of the synchronization measurement according to the system frame information, so that the terminal can maintain synchronization with the first cell.

[0138] In combination with some embodiments of the first aspect, in some embodiments, the downlink control information DCI is scrambled by a radio network temporary identity (RNTI).

[0139] In the above embodiment, the downlink control information DCI is scrambled using the RNTI to implement encryption of the DCI, thereby improving the transmission reliability of the second information carried in the downlink control information.

[0140] In conjunction with some embodiments of the first aspect, in some embodiments, the radio network temporary identifier RNTI includes one of the following:

[0141] A first RNTI, where the first RNTI includes: a Cell-Radio Network Temporary Identity (RNTI, C-RNTI);

[0142] Second RNTI; the second RNTI is different from the first RNTI.

[0143] In the above embodiment, the downlink control information DCI can be scrambled using the C-RNTI or the second RNTI. On the one hand, the scrambling flexibility of the downlink control information DCI is improved. On the other hand, when the terminal descrambles, it can at least determine the cell to which the information carried by the DCI is directed based on the descrambled RNTI.

[0144] In conjunction with some embodiments of the first aspect, in some embodiments, the method further includes:

[0145] Before the first cell serves as the serving cell of the terminal, the first cell sends first capability information of the terminal; wherein the first capability information is used to determine whether the first cell can serve as the serving cell of the terminal.

[0146] In the above embodiment, before switching to the first cell, the terminal may send the first capability information so that the current serving cell of the terminal can determine whether the first cell can serve as the serving cell of the terminal, so as to accept or reject the terminal's switching to the first cell.

[0147] In conjunction with some embodiments of the first aspect, in some embodiments, the first capability information indicates at least one of the following:

[0148] whether the terminal supports the first cell as a primary cell;

[0149] Whether the terminal supports the first cell as a secondary cell of the terminal.

[0150] In the above embodiment, the first capability information of the terminal indicates whether the terminal supports the first cell as the primary cell or whether the terminal supports the first cell as the secondary cell of the terminal, so that the current serving cell of the terminal can accept or reject the terminal from switching to the first cell according to the capability of the terminal, thereby reducing the situation of switching failure.

[0151] In conjunction with some embodiments of the first aspect, in some embodiments, the method further includes:

[0152] The terminal supports the first cell as the primary cell, and the terminal switches to the first cell.

[0153] In the above embodiment, when the terminal supports the first cell as the primary cell, the terminal switches to the first cell, thereby improving the success rate of cell switching.

[0154] In conjunction with some embodiments of the first aspect, in some embodiments, the terminal supports the first cell as the primary cell, and the terminal switches to the first cell, including:

[0155] The first cell supports being a primary cell, and the terminal supports the first cell as a primary cell, and the terminal switches to the first cell.

[0156] In the above embodiment, when the terminal supports the first cell as the primary cell and the first cell also has the ability to independently serve the terminal, that is, the first cell supports being the primary cell, the terminal switches to the first cell, thereby improving the success rate of the cell switching and ensuring that the terminal can communicate normally after the switch.

[0157] In combination with some embodiments of the first aspect, in some embodiments, the first cell does not support being a primary cell, and the terminal does not switch to the first cell.

[0158] In the above embodiment, when the terminal does not support the first cell as the primary cell, the terminal does not switch to the first cell, thereby reducing the situation where the cell switching fails or the terminal cannot communicate normally after switching.

[0159] In conjunction with some embodiments of the first aspect, in some embodiments, the method further includes:

[0160] Before switching to the first cell, a first message sent by the third cell is received, wherein the first message includes at least one of the following:

[0161] identification information of the first cell;

[0162] cell information of the first cell;

[0163] a timing offset between the first cell and the third cell;

[0164] a communication configuration of the first cell;

[0165] the first configuration;

[0166] The second configuration.

[0167] In the above embodiment, before the terminal prepares to switch cells, it can receive a first message sent by the current serving cell, i.e., the third cell, and based on the above information carried in the first message, determine the target cell to be switched, i.e., the first cell, and the relevant configuration information of the first cell, so that the terminal can switch from the third cell to the first cell and establish synchronization with the first cell.

[0168] In conjunction with some embodiments of the first aspect, in some embodiments, the communication configuration includes at least one of the following:

[0169] Radio Bearer (RB) configuration;

[0170] Protocol Data Unit (PDU) session configuration.

[0171] In the above embodiment, before the terminal prepares to perform cell switching, it can receive the radio bearer RB configuration and / or PDU session configuration of the first cell sent by the third cell, so that the terminal can exchange information with the first cell after switching to the first cell.

[0172] In conjunction with some embodiments of the first aspect, in some embodiments, the method further includes:

[0173] The radio resource control (RRC) connection between the terminal and the first cell is released, and the terminal sends an RRC connection recovery request to the second cell; the RRC connection recovery request indicates that the anchor cell of the terminal is the first cell.

[0174] In the above embodiment, after the RRC connection between the terminal and the first cell is released, since the first cell does not send a paging cell, the terminal cannot restore the RRC connection with the first cell. In order to ensure the communication of the terminal, the terminal may send an RRC connection recovery request to the second cell, and the RRC connection recovery request indicates that the anchor cell storing the access layer (Access Layer, AS) context information of the terminal is the first cell, so that the second cell obtains the access layer AS context information of the terminal from the first cell to quickly establish an RRC connection between the second cell and the terminal.

[0175] In a second aspect, an embodiment of the present disclosure provides a synchronization method, wherein the method includes:

[0176] A first cell sends first information; the first information is used for the terminal to maintain synchronization with the first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0177] Synchronization signal broadcast channel block SSB;

[0178] One or more system information blocks (SIBs);

[0179] Paging message.

[0180] In the above embodiment, for the first cell that does not send SSB, SIB and paging messages, the first cell can send the first information to the terminal, so that the terminal can maintain synchronization with the first cell based on the first information, thereby ensuring time and frequency synchronization between the terminal and the first cell and ensuring normal mobility of the terminal when the first cell does not send SSB and network energy saving is achieved.

[0181] In a third aspect, an embodiment of the present disclosure provides a synchronization method, wherein the method includes:

[0182] The second cell sends first information to the terminal; the first information is used for the terminal to maintain synchronization with the first cell.

[0183] The second cell is a neighboring cell of the first cell. The first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0184] Synchronization signal broadcast channel block SSB;

[0185] One or more system information blocks (SIBs);

[0186] Paging message.

[0187] In the above embodiment, for the first cell that does not send SSB, SIB and paging messages, the synchronization reference cell of the first cell, that is, the second cell, can send the first information to the terminal, so that the terminal can maintain synchronization with the first cell based on the first information, thereby ensuring the time and frequency synchronization between the terminal and the first cell and ensuring the normal mobility of the terminal when the first cell does not send SSB and network energy saving is achieved.

[0188] In a fourth aspect, an embodiment of the present disclosure provides a synchronization method, wherein the method includes:

[0189] The third cell obtains first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal;

[0190] In some embodiments, the third cell is a neighboring cell of the first cell.

[0191] The first cell does not send one or more of the following:

[0192] Synchronization signal broadcast channel block SSB;

[0193] One or more system information blocks (SIBs);

[0194] Paging message.

[0195] In the above embodiment, before the terminal switches to the first cell, the current service cell of the terminal, i.e., the third cell, can obtain the first capability information of the terminal to determine whether the terminal can switch to the first cell based on the first capability information, so as to reduce the situation where the cell switching fails or the terminal cannot communicate normally after switching.

[0196] In a fifth aspect, an embodiment of the present disclosure provides a synchronization method, wherein the method is performed by a communication system, and the method includes:

[0197] Before the terminal switches to the first cell, the third cell obtains first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal.

[0198] In some embodiments, the third cell is a neighboring cell of the first cell;

[0199] After the terminal switches to the first cell, the first cell and / or the second cell sends first information.

[0200] In some embodiments, the second cell is a neighboring cell of the first cell.

[0201] The terminal maintains synchronization with the first cell according to the first information; the first cell does not send one or more of the following:

[0202] Synchronization signal broadcast channel block SSB;

[0203] One or more system information blocks (SIBs);

[0204] Paging message.

[0205] In a sixth aspect, an embodiment of the present disclosure provides a terminal, wherein the terminal includes:

[0206] The processing module is configured to maintain synchronization with a first cell according to the first information; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0207] Synchronization signal broadcast channel block SSB;

[0208] One or more system information blocks (SIBs);

[0209] Paging message.

[0210] In a seventh aspect, an embodiment of the present disclosure provides a first access network device, wherein the first access network device includes:

[0211] The first transceiver module is configured to send first information; the first information is used for the terminal to maintain synchronization with a first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0212] Synchronization signal broadcast channel block SSB;

[0213] One or more system information blocks (SIBs);

[0214] Paging message.

[0215] In an eighth aspect, an embodiment of the present disclosure provides a second access network device, wherein the second access network device includes:

[0216] The second transceiver module is configured to send first information, wherein the first information is used for the terminal to maintain synchronization with the first cell; wherein the second cell is a neighboring cell of the first cell; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following:

[0217] Synchronization signal broadcast channel block SSB;

[0218] One or more system information blocks (SIBs);

[0219] Paging message.

[0220] In a ninth aspect, an embodiment of the present disclosure provides a third access network device, wherein the third access network device includes:

[0221] A third transceiver module is configured to obtain first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal; the third cell is a neighboring cell of the first cell;

[0222] The first cell does not send one or more of the following:

[0223] Synchronization signal broadcast channel block SSB;

[0224] One or more system information blocks (SIBs);

[0225] Paging message.

[0226] In the tenth aspect, an embodiment of the present disclosure provides a communication system, wherein the communication system includes a terminal, a first access network device, a second access network device and a third access network device, the terminal is configured to implement the synchronization method described in the optional implementation manner of the first aspect, the first access network device is configured to implement the synchronization method described in the optional implementation manner of the second aspect, the second access network device is configured to implement the synchronization method described in the optional implementation manner of the third aspect, and the third access network device is configured to implement the synchronization method described in the optional implementation manner of the fourth aspect.

[0227] In an eleventh aspect, an embodiment of the present disclosure provides a communication device, the communication device comprising:

[0228] one or more processors;

[0229] The processor is used to call instructions to enable the communication device to execute the synchronization method described in the optional implementation of the first aspect, the second aspect, the third aspect or the fourth aspect.

[0230] In the twelfth aspect, an embodiment of the present disclosure provides a storage medium, wherein the storage medium stores instructions, which, when the instructions are executed on a communication device, enable the communication device to execute the synchronization method described in the optional implementation of the first aspect, the second aspect, the third aspect or the fourth aspect.

[0231] In a thirteenth aspect, an embodiment of the present disclosure provides a program product, which, when executed by a communication device, enables the communication device to execute the synchronization method described in the optional implementation of the first aspect, the second aspect, the third aspect, or the fourth aspect.

[0232] In a fourteenth aspect, an embodiment of the present disclosure provides a computer program, which, when executed on a computer, enables the computer to execute the synchronization method described in the optional implementation of the first aspect, the second aspect, the third aspect, or the fourth aspect.

[0233] It is understandable that the above-mentioned terminal, first access network device, second access network device, third access network device, communication device, communication system, storage medium, program product, and computer program are all used to perform the method provided by the embodiments of the present disclosure. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects of the corresponding methods and will not be repeated here.

[0234] The present disclosure provides a synchronization method and apparatus, a communication device, a communication system, and a storage medium. In some embodiments, the terms synchronization method, information processing method, and information transmission method are interchangeable; the terms information indicating device, information processing device, and information transmission device are interchangeable; and the terms communication system and information processing system are interchangeable.

[0235] The embodiments of the present disclosure are not exhaustive and are merely illustrative of some embodiments, and are not intended to be a specific limitation on the scope of protection of the present disclosure. In the absence of contradiction, each step in a certain embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a certain embodiment can also be implemented as an independent embodiment, and the order of the steps in a certain embodiment can be arbitrarily exchanged. In addition, the optional implementation methods in a certain embodiment can be arbitrarily combined; in addition, the embodiments can be arbitrarily combined. For example, some or all steps of different embodiments can be arbitrarily combined, and a certain embodiment can be arbitrarily combined with the optional implementation methods of other embodiments.

[0236] In each embodiment of the present disclosure, unless otherwise specified or provided for by logic, the terms and / or descriptions between the embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form a new embodiment based on their inherent logical relationships.

[0237] The terms used in the embodiments of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0238] In the embodiments of the present disclosure, unless otherwise specified, elements expressed in the singular, such as "a", "an", "the", "above", "said", "the", "the", etc., may mean "one and only one", or "one or more", "at least one", etc. For example, when using articles such as "a", "an", "the" in English in translation, the noun following the article may be understood as a singular expression or a plural expression.

[0239] In the embodiments of the present disclosure, “plurality” refers to two or more.

[0240] In some embodiments, the terms "at least one," "one or more," "a plurality of," "multiple," etc. may be used interchangeably.

[0241] In some embodiments, descriptions such as "at least one of A and B," "A and / or B," "in one case A, in another case B," or "in one case A, in another case B" may include the following technical solutions depending on the situation: in some embodiments, A (A is executed independently of B); in some embodiments, B (B is executed independently of A); in some embodiments, execution is selected from A and B (A and B are selectively executed); and in some embodiments, A and B (both A and B are executed). The same applies when there are more branches such as A, B, and C.

[0242] In some embodiments, "A or B" and other descriptions may include the following technical solutions depending on the situation: in some embodiments, A (A is executed independently of B); in some embodiments, B (B is executed independently of A); in some embodiments, execution is selected from A and B (A and B are selectively executed). The above is also applicable when there are more branches such as A, B, C, etc.

[0243] The prefixes such as "first" and "second" in the embodiments of the present disclosure are only used to distinguish different description objects and do not constitute any restriction on the position, order, priority, quantity or content of the description objects. For the statement of the description object, please refer to the description in the context of the claims or embodiments, and no unnecessary restriction should be constituted due to the use of prefixes. For example, if the description object is a "field", the ordinal number before the "field" in the "first field" and the "second field" does not limit the position or order between the "fields". "First" and "second" do not limit whether the "fields" they modify are in the same message, nor do they limit the order of the "first field" and the "second field". For another example, if the description object is a "level", the ordinal number before the "level" in the "first level" and the "second level" does not limit the priority between the "levels". For another example, the number of description objects is not limited by the ordinal number and can be one or more. Taking "first device" as an example, the number of "devices" can be one or more. In addition, the objects modified by different prefixes can be the same or different. For example, if the description object is "device", then the "first device" and the "second device" can be the same device or different devices, and their types can be the same or different; for another example, if the description object is "information", then the "first information" and the "second information" can be the same information or different information, and their contents can be the same or different.

[0244] In some embodiments, “including A,” “comprising A,” “used to indicate A,” and “carrying A” can be interpreted as directly carrying A or indirectly indicating A.

[0245] In some embodiments, terms such as "...", "determine...", "in the case of...", "at the time of...", "when...", "if...", "if...", etc. can be used interchangeably.

[0246] In some embodiments, terms such as "greater than", "greater than or equal to", "not less than", "more than", "more than or equal to", "not less than", "higher than", "higher than or equal to", "not less than", and "above" can be replaced with each other, and terms such as "less than", "less than or equal to", "not greater than", "less than", "less than or equal to", "not more than", "lower than", "lower than or equal to", "not higher than", and "below" can be replaced with each other.

[0247] In some embodiments, devices, etc. can be interpreted as physical or virtual, and their names are not limited to the names recorded in the embodiments. Terms such as "device", "equipment", "device", "circuit", "network element", "node", "function", "unit", "section", "system", "network", "chip", "chip system", "entity", and "subject" can be used interchangeably.

[0248] In some embodiments, "network" can be interpreted as devices included in the network (eg, access network equipment, core network equipment, etc.).

[0249] In some embodiments, the terms "access network device (AN device)", "radio access network device (RAN device)", "base station (BS)", "radio base station" "fixed station", "node", "access point", "transmission point (TP)", "reception point (RP)", "transmission / reception point (TRP)", "panel", "antenna panel", "antenna array", "cell", "macro cell", "small cell", "femto cell", "pico cell", "sector", "cell group", "serving cell", "carrier", "component carrier", "bandwidth part (BWP)" and the like may be used interchangeably.

[0250] In some embodiments, the terms "terminal", "terminal device", "user equipment (UE)", "user terminal", "mobile station (MS)", "mobile terminal (MT)", subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, etc. can be used interchangeably.

[0251] In some embodiments, the access network device, the core network device, or the network device can be replaced by a terminal. For example, the various embodiments of the present disclosure can also be applied to a structure in which the communication between the access network device, the core network device, or the network device and the terminal is replaced by communication between multiple terminals (for example, device-to-device (D2D), vehicle-to-everything (V2X), etc.). In this case, it is also possible to set the structure in which the terminal has all or part of the functions of the access network device. In addition, terms such as "uplink" and "downlink" can also be replaced by terms corresponding to communication between terminals (for example, "side"). For example, uplink channels, downlink channels, etc. can be replaced by side channels, and uplinks, downlinks, etc. can be replaced by side links.

[0252] In some embodiments, the terminal may be replaced by an access network device, a core network device, or a network device. In this case, the access network device, the core network device, or the network device may have a structure that has all or part of the functions of the terminal.

[0253] In some embodiments, obtaining data, information, etc. may comply with the laws and regulations of the country where the data is obtained.

[0254] In some embodiments, data, information, etc. may be obtained with the user's consent.

[0255] In addition, each element, each row, or each column in the table of the embodiment of the present disclosure can be implemented as an independent embodiment, and the combination of any elements, any rows, and any columns can also be implemented as an independent embodiment.

[0256] FIG1 is a schematic diagram showing the architecture of a communication system according to an embodiment of the present disclosure.

[0257] As shown in FIG1 , a communication system 100 includes a terminal 101 , an access network device 102 , and a core network device 103 .

[0258] In some embodiments, the terminal 101 includes, for example, a mobile phone, a wearable device, an Internet of Things device, a car with communication function, a smart car, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical surgery, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, and at least one of a wireless terminal device in a smart home, but is not limited thereto.

[0259] In some embodiments, the access network device 102 can be, for example, a node or device that accesses the terminal to the wireless network. The access network device may include an evolved NodeB (eNB), a next generation evolved NodeB (ng-eNB), a next generation NodeB (gNB), a node B (NB), a home node B (HNB), a home evolved nodeB (HeNB), a wireless backhaul device, a radio network controller (RNC), a base station controller (BSC), a base transceiver station (BTS), a base band unit (BBU), a mobile switching center, a base station in a 6G communication system, an open base station (Open RAN), a cloud base station (Cloud RAN), a base station in other communication systems, and at least one of an access node in a Wi-Fi system, but is not limited thereto.

[0260] In some embodiments, the technical solution of the present disclosure can be applied to the Open RAN architecture. In this case, the interfaces between or within the access network devices involved in the embodiments of the present disclosure can be transformed into internal interfaces of the Open RAN, and the processes and information interactions between these internal interfaces can be implemented through software or programs.

[0261] In some embodiments, the access network device can be composed of a centralized unit (CU) and a distributed unit (DU), where the CU can also be called a control unit. The CU-DU structure can be used to split the protocol layer of the access network device, with the functions of some protocol layers centrally controlled by the CU, and the functions of the remaining part or all of the protocol layers distributed in the DU, which is centrally controlled by the CU, but is not limited to this.

[0262] In some embodiments, the access network device 102 includes: a first access network device 1021 , a second access network device 1022 and a third access network device 1023 .

[0263] In some embodiments, the first access network device 1021 may be a base station of a first cell.

[0264] In some embodiments, the second access network device 1022 may be a base station of a second cell.

[0265] In some embodiments, the third access network device 1023 may be a base station of a third cell.

[0266] In some embodiments, the core network device 103 may be a single device including one or more network elements, or may be multiple devices or a group of devices, each including one or more network elements. The network elements may be virtual or physical. The core network may include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), and a Next Generation Core (NGC).

[0267] It can be understood that the communication system described in the embodiment of the present disclosure is for the purpose of more clearly illustrating the technical solution of the embodiment of the present disclosure, and does not constitute a limitation on the technical solution provided by the embodiment of the present disclosure. Ordinary technicians in this field can know that with the evolution of the system architecture and the emergence of new business scenarios, the technical solution provided by the embodiment of the present disclosure is also applicable to similar technical problems.

[0268] The following embodiments of the present disclosure may be applied to the communication system 100 shown in Figure 1, or a portion thereof, but are not limited thereto. The entities shown in Figure 1 are illustrative only. The communication system may include all or part of the entities shown in Figure 1, or may include other entities outside of Figure 1. The number and form of the entities may be arbitrary. The connection relationship between the entities is illustrative only. The entities may be connected or disconnected, and the connection may be in any manner, including direct or indirect, wired or wireless.

[0269] The embodiments of the present disclosure can be applied to Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 5G new radio (NR), future radio access (FRA), new radio access technology (RAT), new radio (NR), new radio access (NX), future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), Public Land Mobile Network (PLMN) networks, Device-to-Device (D2D) systems, Machine-to-Machine (M2M) systems, Internet of Things (IoT) systems, Vehicle-to-Everything (V2X), systems utilizing other communication methods, and next-generation systems based on and extending these methods. Furthermore, multiple systems may be combined (for example, a combination of LTE or LTE-A with 5G).

[0270] FIG2a is an interactive diagram of a synchronization method according to an embodiment of the present disclosure. As shown in FIG2a, the embodiment of the present disclosure relates to a synchronization method for a communication system 100, the method comprising:

[0271] Step S2101: The third cell obtains the first capability information of the terminal.

[0272] In some embodiments, the base station of the third cell may be a third access network device.

[0273] In some embodiments, the third cell is the cell where the terminal is currently camped.

[0274] In some embodiments, the third cell obtains the first capability information of the terminal from the core network device.

[0275] In some embodiments, the third cell obtains the first capability information of the terminal from an Access and Mobility Management Function (AMF).

[0276] It should be noted that AMF is the control plane access point between the terminal and the wireless core network. It receives all connection and session related information from the terminal and performs registration, connection, reachability and mobility management.

[0277] In some embodiments, the third cell receives the first capability information sent by the terminal.

[0278] In some embodiments, the first capability information of the terminal is used to determine whether the first cell can serve as a serving cell for the terminal.

[0279] It should be noted that the third cell may determine whether the terminal supports handover to the first cell according to the first capability information of the terminal.

[0280] In some embodiments, the first cell and the third cell have overlapping coverage areas.

[0281] In some embodiments, the coverage areas of the first cell and the third cell are adjacent.

[0282] In some embodiments, the first cell and the third cell are neighboring cells.

[0283] In some embodiments, the first cell does not send one or more of the following:

[0284] Synchronization signal broadcast channel block SSB;

[0285] One or more system information blocks (SIBs);

[0286] Paging message.

[0287] In some embodiments, the first cell does not send SSB, system information block SIB and paging message.

[0288] In some embodiments, the first capability information indicates at least one of the following:

[0289] whether the terminal supports the first cell as a primary cell;

[0290] Whether the terminal supports the first cell as a secondary cell of the terminal.

[0291] It is worth noting that the terminal supports the first cell as the primary cell, which means that the terminal supports switching to the first cell; the terminal supports the first cell as the secondary cell of the terminal, which means that the terminal supports access to the first cell but does not support switching to the first cell.

[0292] In some embodiments, the third cell obtains cell-related information of the first cell.

[0293] In some embodiments, the cell-related information is used to determine whether the first cell can serve as a primary cell.

[0294] In some embodiments, the cell-related information includes at least one of the following:

[0295] Cell type information;

[0296] Cell capability information, indicating whether the first cell supports being the primary cell.

[0297] In some embodiments, the cell type information indicates the cell type of the cell.

[0298] In some embodiments, the cell type includes at least one of the following:

[0299] The first type of cells include: SSB / SIB1-less cells;

[0300] Second type cell: The second type cell is different from the first type cell.

[0301] In some embodiments, the SSB / SIB1-less cell does not send one or more of the following:

[0302] Synchronization signal broadcast channel block SSB;

[0303] One or more system information blocks (SIBs);

[0304] Paging message.

[0305] In some embodiments, an SSB / SIB1-less cell may transmit one or more system information blocks (SIBs).

[0306] In some other embodiments, the SSB / SIB1-less cell does not send a system information block SIB. It should be noted that the SSB / SIB1-less cell does not send any system information block SIB.

[0307] It can be understood that the first cell can be an SSB / SIB1-less cell.

[0308] In some embodiments, the cell capability information includes: second capability information indicating whether independent service terminals are supported.

[0309] It can be understood that if the second capability information of the first cell indicates support for independent service terminals, it means that the first cell supports being a primary cell; if the second capability information of the first cell indicates not supporting independent service terminals, it means that the first cell does not support being a primary cell.

[0310] In some embodiments, the terminal supports the first cell as the primary cell, and the third cell determines whether to accept handover of the terminal to the first cell based on cell-related information of the first cell.

[0311] In some embodiments, the terminal supports the first cell as the primary cell, and the third cell determines whether to accept handover of the terminal to the first cell according to cell-related information of the first cell, including at least one of the following:

[0312] The terminal supports the first cell as a primary cell and determines, based on the cell-related information, that the first cell supports being the primary cell, and determines to accept handover of the terminal to the first cell;

[0313] The terminal supports the first cell as a primary cell and determines, according to the cell-related information, that the first cell does not support being a primary cell, and determines to reject handover of the terminal to the first cell.

[0314] It should be noted that the third cell can determine whether to accept or reject the terminal's switching to the first cell by respectively obtaining the first capability information of the terminal and the cell-related information of the target cell to be switched (i.e., the first cell), and based on whether the first capability information and the cell-related information match.

[0315] Step S2102: The third cell sends a second message to the first cell.

[0316] In some embodiments, the first cell receives the second message sent by the third cell.

[0317] In some embodiments, the third cell sends a second message to the first cell based on the first capability information and the cell-related information.

[0318] In some embodiments, the terminal supports the first cell as a primary cell and determines, based on the cell-related information, that the first cell supports being a primary cell, and sends a second message to the first cell.

[0319] In some embodiments, the second message may include, but is not limited to, a handover request message.

[0320] In some embodiments, the second message is used to indicate whether the terminal supports switching to the first cell.

[0321] It can be understood that the third cell sends the second message to the first cell so that the first cell determines to accept or reject the terminal's handover to the first cell.

[0322] In some embodiments, the first cell obtains first capability information of the terminal.

[0323] In some embodiments, the first cell receives a second message sent by the third cell and obtains the first capability information of the terminal.

[0324] It is understandable that after receiving the second message, the first cell can obtain the first capability information of the terminal, and determine whether to accept or reject the terminal's handover to the first cell based on the first capability information and its own cell-related information.

[0325] In some embodiments, obtaining the first capability information of the terminal includes at least one of the following:

[0326] The first cell obtains the first capability information of the terminal from the core network device;

[0327] The first cell receives the first capability information of the terminal sent by the third cell.

[0328] In some embodiments, the second message may carry identification information of the terminal. Thus, after receiving the second message, the first cell may obtain the first capability information of the terminal from the core network device based on the identification information of the terminal in the second message.

[0329] In some embodiments, the first cell obtains the first capability information of the terminal from the access and mobility management function AMF.

[0330] In some embodiments, the second message may carry the first capability information of the terminal. In this way, after receiving the second message, the first cell may directly obtain the first capability information of the terminal based on the second message.

[0331] Step S2103: The first cell sends a third message to the third cell.

[0332] In some embodiments, the terminal is accepted to be switched to the first cell, and the first cell sends a third message to the third cell.

[0333] In some embodiments, the third message may include but is not limited to a handover response message.

[0334] In some embodiments, the third message is used to indicate acceptance or rejection of handover of the terminal to the first cell.

[0335] In some embodiments, the third message is used by the third cell to send the first message to the terminal.

[0336] In some embodiments, the third message includes at least one of the following:

[0337] identification information of the first cell;

[0338] cell information of the first cell;

[0339] a timing offset between the first cell and the third cell;

[0340] a communication configuration of the first cell;

[0341] the first configuration;

[0342] The second configuration.

[0343] It should be noted that the above information may be used to assist the terminal in switching to the first cell and establishing synchronization with the first cell.

[0344] In some embodiments, the identification information of the first cell may include at least one of the following:

[0345] The frequency of the first cell;

[0346] Physical cell identifier (PCI) of the first cell;

[0347] The cell identifier of the first cell.

[0348] In some embodiments, the cell information of the first cell may include, but is not limited to: cell configuration information.

[0349] The cell configuration information may be used to obtain the synchronization and timing relationship of the first cell.

[0350] In some embodiments, the timing offset between the first cell and the third cell is used for synchronization of the terminal with the first cell.

[0351] In some embodiments, the timing offset between the first cell and the third cell indicates at least one of the following:

[0352] the number of system frame numbers (SFNs) that differ between the first cell and the third cell;

[0353] The difference in the number of subframes between the first cell and the third cell;

[0354] The number of time slots that differ between the first cell and the third cell;

[0355] The number of symbols that differ between the first cell and the third cell is symbol.

[0356] In some embodiments, the communication configuration includes at least one of the following:

[0357] Wireless resource configuration;

[0358] Radio bearer RB configuration;

[0359] Protocol Data Unit (PDU) session configuration.

[0360] In some embodiments, the wireless resource configuration may include configuration information of a physical channel.

[0361] In some embodiments, the radio bearer (RB) configuration may include at least one of the following:

[0362] Configuration information of Layer (L) 2 protocol stack;

[0363] Data Radio Bearer (DRB) configuration information.

[0364] In some embodiments, the configuration information of the L2 protocol stack may include but is not limited to: Service Data Adaption Protocol (SDAP), Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC) protocol and Media Access Control (MAC) protocol.

[0365] In some embodiments, the first configuration is used for the terminal to maintain synchronization with the first cell according to the first signal sent by the second cell. It is understandable that the first configuration may be a measurement configuration for the first signal sent by the second cell.

[0366] It should be noted that the second cell may be a synchronization reference cell of the first cell. It is understandable that the terminal may measure the first signal sent by the second cell based on the first configuration information to achieve synchronization with the first cell.

[0367] In some embodiments, the first cell and the second cell have overlapping coverage areas.

[0368] In some embodiments, the coverage areas of the first cell and the second cell are adjacent.

[0369] In some embodiments, the first cell and the second cell are neighboring cells.

[0370] In some embodiments, the second cell sends one or more of the following:

[0371] Synchronization signal broadcast channel block SSB;

[0372] One or more system information blocks (SIBs);

[0373] Paging message.

[0374] In some embodiments, the second configuration is used for the terminal to maintain synchronization with the first cell according to the second signal sent by the first cell. It can be understood that the second configuration can be a measurement configuration of the second signal sent by the first cell.

[0375] Step S2104: The third cell sends a first message to the terminal.

[0376] In some embodiments, the terminal receives a first message sent by a third cell.

[0377] In some embodiments, the first message is used to indicate whether the terminal can be handed over to the first cell.

[0378] In some embodiments, the first message is used for synchronizing the terminal with the first cell.

[0379] In some embodiments, the third cell sends the first message to the terminal according to the third message.

[0380] In some embodiments, the first message includes at least one of the following:

[0381] identification information of the first cell;

[0382] cell information of the first cell;

[0383] a timing offset between the first cell and the third cell;

[0384] communication configuration of the first cell;

[0385] the first configuration;

[0386] The second configuration.

[0387] In some embodiments, the communication configuration includes at least one of the following:

[0388] Radio bearer RB configuration;

[0389] Protocol Data Unit (PDU) session configuration.

[0390] It can be understood that after the third cell receives the third message sent by the first cell, it sends the above information carried in the third message to the terminal through the first message, so that the terminal can switch from the third cell to the first cell based on the above information and establish synchronization with the first cell.

[0391] Step S2105: The terminal switches to the first cell.

[0392] In some embodiments, the terminal is handed over from the third cell to the first cell.

[0393] In some embodiments, the terminal switches from the third cell to the first cell according to the first message sent by the third cell.

[0394] It should be noted that the terminal determines the first cell to be switched according to the information carried in the first message, switches from the third cell to the first cell, and establishes synchronization with the first cell.

[0395] In some embodiments, the first cell is a primary cell of the terminal.

[0396] In some embodiments, the first cell is a serving cell of the terminal, and the terminal has only one serving cell.

[0397] Step S2106: The first cell sends the first information.

[0398] In some embodiments, the first cell sends the first information to the terminal.

[0399] In some embodiments, the terminal receives first information sent by the first cell.

[0400] In some embodiments, the first cell sends the first information to the second cell, so that the second cell can send the received first information to the terminal.

[0401] In some embodiments, the terminal may determine the first information according to a protocol agreement.

[0402] In some embodiments, the first information is used for the terminal to maintain synchronization with the first cell.

[0403] It should be noted that since the first cell does not send the SSB, the terminal cannot maintain synchronization with the first cell based on the SSB; based on this, the terminal can obtain the first information and use the first information to maintain synchronization with the first cell.

[0404] In some embodiments, the first information includes at least one of the following:

[0405] The control signaling includes: second information used to maintain synchronization between the terminal and the first cell;

[0406] The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

[0407] In some embodiments, the control signaling may include: downlink control information DCI.

[0408] In some embodiments, the first cell may send downlink control information DCI to the terminal, so that the terminal maintains synchronization with the first cell based on second information carried in the downlink control information DCI.

[0409] In some embodiments, the second information includes: system frame SFN information.

[0410] It should be noted that the time unit for synchronization between the terminal and the access network device is the system frame, and the terminal can be synchronized based on the system frame SFN information.

[0411] In some embodiments, the second configuration may be a measurement configuration of the second signal.

[0412] It should be noted that, based on the second configuration, the terminal may measure the second signal sent by the first cell, so that the terminal maintains synchronization with the first cell.

[0413] Step S2107: The first cell sends a second signal or control signaling.

[0414] In some embodiments, the second signal includes at least one of the following:

[0415] Channel state information CSI-reference signal RS;

[0416] Tracking Reference Signal (TRS);

[0417] The third signal.

[0418] In some embodiments, CSI / RS is used for the terminal to maintain downlink synchronization with the first cell.

[0419] In some embodiments, CSI / RS is also used for RRM measurement of the terminal.

[0420] In some embodiments, the tracking reference signal TRS is used to maintain synchronization between the terminal and the first cell.

[0421] It should be noted that the frequencies of the physical crystal oscillators of the first access network device and the terminal will have slight deviations, and it is impossible to achieve complete consistency. This causes the RF carrier signal received by the terminal to have a phase deviation. In the demodulated symbol constellation diagram of the received subcarrier, this appears as a phase rotation. That is, the received modulation symbol deviates from a certain phase angle. This is caused by the accumulation of frequency deviation over time. In this case, it is necessary to track the reference signal TRS to track the rotation phase of other data signals. The frequency and time errors can be estimated based on the TRS. The received data can compensate for these errors and rotate back to the originally transmitted modulation coordinate position to keep the terminal synchronized with the first cell.

[0422] In some embodiments, the third signal is a signal used for synchronization between the terminal and the first cell, and the third signal is different from the SSB, the CSI-RS and / or the TRS.

[0423] It should be noted that the first cell separately configures a third signal for the terminal to maintain synchronization with the first cell.

[0424] In some embodiments, the third signal also carries system frame SFN information. Thus, the third signal carries the system frame SFN information, so that the terminal can obtain the system frame SFN information according to the third signal to determine relevant measurement parameters of synchronization measurement to maintain synchronization with the first cell.

[0425] In some embodiments, the control signaling includes: second information for maintaining synchronization between the terminal and the first cell;

[0426] It is understandable that the first cell may send the second information to the terminal by sending control signaling to the terminal, so that the terminal can maintain synchronization with the first cell based on the second information.

[0427] In some embodiments, the control signaling includes: downlink control information DCI.

[0428] In some embodiments, the downlink control information DCI carries system frame SFN information.

[0429] It can be understood that the first cell sends DCI carrying system frame SFN information to the terminal, so that the terminal determines relevant measurement parameters of synchronization measurement based on the system frame SFN information in the control signaling to maintain synchronization with the first cell.

[0430] In some embodiments, the downlink control information DCI is scrambled by a radio network temporary identifier RNTI.

[0431] It should be noted that the cyclic redundancy check (CRC) of the downlink control information DCI can be XORed with the RNTI sequence to obtain the scrambled downlink control information DCI. By scrambling the downlink control information DCI, cells and channels can be distinguished.

[0432] In some embodiments, the radio network temporary identifier (RNTI) includes one of the following:

[0433] A first RNTI, wherein the first RNTI includes: a cell radio network temporary identifier C-RNTI;

[0434] Second RNTI; the second RNTI is different from the first RNTI.

[0435] It should be noted that the downlink control information DCI may be scrambled based on the cell radio network temporary identifier C-RNTI, so that it can be determined that the downlink control information DCI is DCI for a single cell.

[0436] In some embodiments, the second RNTI may be a newly configured RNTI.

[0437] In some embodiments, the second RNTI is used to obtain synchronization information.

[0438] It should be noted that the downlink control information DCI can be encrypted based on the second RNTI; after receiving the downlink control information DCI, the terminal can use the second RNTI to descramble the DCI to determine whether the received DCI carries the second information based on the descrambling result.

[0439] In some embodiments, the control signaling includes at least one of the following:

[0440] The control signaling sent periodically;

[0441] The control signaling sent based on the request of the terminal;

[0442] The control signaling sent based on the triggering of a preset event.

[0443] It should be noted that the first cell may periodically send the control signaling to the terminal, so that the terminal can maintain synchronization with the first cell according to the second information carried in the control signaling.

[0444] In some embodiments, the first cell may receive a request sent by the terminal, and send the control signaling to the terminal based on the request.

[0445] In some embodiments, the request may include, but is not limited to, a synchronization request.

[0446] It should be noted that after receiving the synchronization request sent by the terminal, the first cell may send the control signaling containing the second information to the terminal, so that the terminal maintains synchronization with the first cell according to the second information carried in the control signaling.

[0447] In some embodiments, the preset event includes at least one of the following:

[0448] a measurement event of the terminal;

[0449] The transmission scheduling feedback event of the terminal.

[0450] In some embodiments, the measurement event may include but is not limited to: an RRM measurement event.

[0451] It should be noted that the terminal will report the RRM measurement report to the first cell, and the first cell may determine whether to send control signaling carrying the second information to the terminal based on the RRM measurement report.

[0452] Exemplarily, if the RRM measurement report indicates that a measurement value of a reference signal of a serving cell of the terminal is lower than a preset threshold, the first cell may send a control signaling carrying the second information to the terminal.

[0453] Step S2108: The terminal maintains synchronization with the first cell based on the second signal or control signaling.

[0454] In some embodiments, the terminal may measure the second signal sent by the first cell based on the second configuration to maintain synchronization with the first cell.

[0455] In some embodiments, the second configuration includes at least one of the following:

[0456] Measurement period;

[0457] Measurement window;

[0458] Measurement bias;

[0459] Measure the signal.

[0460] It should be noted that the measurement signal is used by the terminal to determine the second signal that needs to be measured.

[0461] In some embodiments, the measurement window may include: a measurement gap.

[0462] In some embodiments, the timing information of the measurement gap configuration of the second signal is determined based on downlink timing information of the first cell.

[0463] It should be noted that the first cell configures a measurement gap for measuring the second signal for the terminal, and the timing information configured for the measurement gap of the second signal is determined based on the downlink timing information of the first cell, so that the terminal can measure the second signal in the measurement gap to achieve synchronization with the first cell.

[0464] In some embodiments, the second signal is also used for radio resource management RRM of the terminal.

[0465] In some embodiments, the second configuration further includes: an SSB measurement timing SMTC configuration for each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration is determined based on the downlink timing information of the first cell.

[0466] It should be noted that the SMTC configuration in the second configuration is used to indicate a measurement window for the terminal to perform radio resource management RRM measurement based on the second signal.

[0467] In some embodiments, the terminal may maintain synchronization with the first cell based on the second information carried in the control signaling.

[0468] Step S2109: The first cell releases the RRC connection with the terminal.

[0469] In some embodiments, the first cell receives an RRC release request sent by the terminal and releases the RRC connection with the terminal.

[0470] In some embodiments, the first cell may release the RRC connection with the terminal on its own.

[0471] In some embodiments, the first cell releases the RRC connection with the terminal, and the terminal switches from the RRC connected state to the RRC non-connected state.

[0472] In some embodiments, the RRC non-connected state includes: an RRC idle state and / or an RRC inactive state.

[0473] In some embodiments, the second cell includes: configuration-related information of a notification area (RNA) of a radio access network (RAN); the configuration-related information includes: identifiers of one or more cells; the configuration-related information does not include the identifier of the first cell.

[0474] In some embodiments, the third cell includes: configuration-related information of a notification area RNA of a radio access network RAN; the configuration-related information includes: identifiers of one or more cells; the configuration-related information does not include the identifier of the first cell.

[0475] It can be understood that, since the first cell does not send a paging message, the RAN of the paging terminal does not include the first cell.

[0476] Step S2110: The terminal sends an RRC connection recovery request to the second cell.

[0477] In some embodiments, the terminal in the RRC non-connected state sends an RRC connection recovery request to the second cell.

[0478] In some embodiments, the terminal in the RRC inactive state sends an RRC connection recovery request to the second cell.

[0479] In some embodiments, the RRC connection recovery request indicates that the anchor cell of the terminal is the first cell.

[0480] It should be noted that the anchor cell may store the access layer AS context information of the terminal.

[0481] Step S2111: The second cell sends a terminal context request message to the first cell.

[0482] In some embodiments, the first cell receives a terminal context request message sent by the second cell.

[0483] In some embodiments, the terminal context request message is sent after the second cell receives the RRC connection recovery request message sent by the terminal.

[0484] It should be noted that after the second cell receives the RRC connection recovery request message sent by the terminal, if the RRC connection recovery request message indicates that the anchor cell of the terminal is the first cell, the second cell may send a terminal context request message to the first cell.

[0485] In some embodiments, the terminal context request message is used to obtain access layer AS context information of the terminal.

[0486] In some embodiments, the access layer AS context information may include, but is not limited to, at least one of: radio resource control configuration, data radio bearer parameters, terminal identification information, and cell identification information.

[0487] It should be noted that the access layer AS context information can assist the second cell and the terminal in quickly establishing an RRC connection.

[0488] Step S2112: The first cell sends the access stratum AS context information of the terminal to the second cell.

[0489] In some embodiments, the first cell sends the stored access stratum AS context information of the terminal to the second cell.

[0490] In some embodiments, the term "information" can be interchangeable with terms such as "message", "signal", "signaling", "report", "configuration", "indication", "instruction", "command", "channel", "parameter", "field", and "data".

[0491] In some embodiments, the term "send" can be interchanged with terms such as "transmit", "report", and "transmit".

[0492] The synchronization method according to the embodiments of the present disclosure may include at least one of steps S2101 to S2112. For example, steps S2101 to S2105 may be implemented as independent embodiments, steps S2105 to S2108 may be implemented as independent embodiments, and steps S2109 to S2112 may be implemented as independent embodiments, but are not limited thereto.

[0493] In some embodiments, step S2101 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that when the current serving cell of the terminal is the first cell, before the terminal needs to switch to another first cell, the current serving cell of the terminal can know whether the terminal supports the first cell as the primary cell without obtaining the first capability information of the terminal.

[0494] In some embodiments, step S2106 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understandable that the terminal may determine the first information according to the protocol, without the need for the first cell to send it.

[0495] In some embodiments, steps S2107 and S2108 are optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal can maintain synchronization with the first cell based on the first signal sent by the second cell, without the first cell sending a second signal or control signaling.

[0496] In some embodiments, steps S2110 and S2111 are optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that if the anchor cell of the terminal is not the first cell, the second cell does not need to obtain the terminal context request message from the first cell.

[0497] FIG2b is an interactive diagram of a synchronization method according to an embodiment of the present disclosure. As shown in FIG2b, the embodiment of the present disclosure relates to a synchronization method for a communication system 100, the method comprising:

[0498] Step S2201: The third cell obtains the first capability information of the terminal.

[0499] In some embodiments, the optional implementation of step S2201 can refer to the optional implementation of step S2101 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0500] Step S2202: The third cell sends a second message to the first cell.

[0501] In some embodiments, the optional implementation of step S2202 can refer to the optional implementation of step S2102 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0502] Step S2203: The first cell sends a third message to the third cell.

[0503] In some embodiments, the optional implementation of step S2203 can refer to the optional implementation of step S2103 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0504] Step S2204: The third cell sends a first message to the terminal.

[0505] In some embodiments, the optional implementation of step S2204 can refer to the optional implementation of step S2104 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0506] Step S2205: The terminal switches to the first cell.

[0507] In some embodiments, the optional implementation of step S2205 can refer to the optional implementation of step S2105 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0508] Step S2206: The second cell sends the first information to the terminal.

[0509] In some embodiments, the terminal receives the first information sent by the second cell. It should be noted that the second cell may be a synchronization reference cell of the first cell, and the second cell may send the first information to the terminal so that the terminal maintains synchronization with the first cell based on the first information.

[0510] In some embodiments, the second cell is different from the first cell. It is understood that the second cell may be a normal cell.

[0511] In some embodiments, the terminal may determine the first information according to a protocol agreement.

[0512] In some embodiments, the first information is used for the terminal to maintain synchronization with the first cell.

[0513] It should be noted that since the first cell does not send the SSB, the terminal cannot maintain synchronization with the first cell based on the SSB; based on this, the terminal can obtain the first information and use the first information to maintain synchronization with the first cell.

[0514] In some embodiments, the first information includes:

[0515] The first configuration is used for the terminal to maintain synchronization with the first cell according to the first signal sent by the second cell. In some embodiments, the first configuration may be a measurement configuration of the first signal.

[0516] It should be noted that, since the second cell is a synchronization reference cell of the first cell, the terminal may measure the first signal sent by the second cell based on the first configuration, so that the terminal maintains synchronization with the first cell.

[0517] Step S2207: The second cell sends a first signal.

[0518] In some embodiments, the first signal may include: a synchronization signal broadcast channel block SSB.

[0519] It should be noted that the second cell is different from the first cell. The second cell can send SSB so that the terminal can determine the downlink timing information of the second cell based on the SSB sent by the second cell, and further determine the downlink timing information of the first cell to maintain synchronization with the first cell.

[0520] Step S2208: The terminal maintains synchronization with the first cell based on the first signal.

[0521] In some embodiments, the terminal may measure the first signal sent by the second cell based on the first configuration to maintain synchronization with the first cell.

[0522] In some embodiments, the first configuration includes at least one of the following:

[0523] Measurement period;

[0524] Measurement window;

[0525] Measurement bias;

[0526] cell information of the second cell;

[0527] Timing information is used by the terminal to determine the downlink timing of the first cell.

[0528] In some embodiments, the timing information includes at least one of the following:

[0529] downlink timing information of the second cell;

[0530] The timing offset between the second cell and the first cell.

[0531] In some embodiments, the measurement window may include: a measurement gap and / or an SSB measurement timing SMTC.

[0532] In some embodiments, timing information of the measurement gap configuration of the first signal is determined based on downlink timing information of the second cell.

[0533] It should be noted that the second cell configures a measurement gap for measuring the first signal for the terminal, and the timing information configured for the measurement gap of the first signal is determined based on the downlink timing information of the second cell, so that the terminal can measure the first signal in the measurement gap to achieve synchronization with the first cell.

[0534] In some embodiments, the first configuration further includes: an SSB measurement timing SMTC configuration for each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration is determined based on the downlink timing information of the second cell.

[0535] It should be noted that the SMTC configuration in the first configuration is used to indicate a measurement window for the terminal to perform radio resource management RRM measurement based on the first signal.

[0536] Step S2209: The first cell releases the RRC connection with the terminal.

[0537] In some embodiments, the optional implementation of step S2209 can refer to the optional implementation of step S2109 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0538] Step S2210: The terminal sends an RRC connection recovery request to the second cell.

[0539] In some embodiments, the optional implementation of step S2210 can refer to the optional implementation of step S2110 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0540] Step S2211: The second cell sends a terminal context request message to the first cell.

[0541] In some embodiments, the optional implementation of step S2211 can refer to the optional implementation of step S2111 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0542] Step S2212: The first cell sends the access stratum AS context information of the terminal to the second cell.

[0543] In some embodiments, the optional implementation of step S2212 can refer to the optional implementation of step S2112 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0544] The synchronization method according to the embodiments of the present disclosure may include at least one of steps S2201 to S2212. For example, steps S2201 to S2205 may be implemented as independent embodiments, steps S2205 to S2208 may be implemented as independent embodiments, and steps S2209 to S2212 may be implemented as independent embodiments, but are not limited thereto.

[0545] In some embodiments, step S2201 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that when the current serving cell of the terminal is the first cell, before the terminal needs to switch to another first cell, the current serving cell of the terminal can know whether the terminal supports the first cell as the primary cell without obtaining the first capability information of the terminal.

[0546] In some embodiments, step S2206 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal may determine the first information according to the protocol, or the terminal may directly receive the first information sent by the first cell without the need for the second cell to send it.

[0547] In some embodiments, steps S2207 and S2208 are optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal can maintain synchronization with the first cell based on the second signal or control signaling sent by the first cell, without the second cell sending the first signal.

[0548] In some embodiments, steps S2110 and S2111 are optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that if the anchor cell of the terminal is not the first cell, the second cell does not need to obtain the terminal context request message from the first cell.

[0549] FIG3a is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG3a, the embodiment of the present disclosure relates to a synchronization method, which is executed by terminal 101 and includes:

[0550] Step S3101: The terminal sends first capability information.

[0551] In some embodiments, the terminal sends the first capability information to the third cell.

[0552] In some embodiments, the optional implementation of step S3101 can refer to the optional implementation of step S2101 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0553] Step S3102: The terminal receives the first message sent by the third cell.

[0554] In some embodiments, the third cell sends the first message to the terminal.

[0555] In some embodiments, the optional implementation of step S3102 can refer to the optional implementation of step S2104 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0556] Step S3103: The terminal switches to the first cell.

[0557] In some embodiments, the terminal is handed over from the third cell to the first cell.

[0558] In some embodiments, the optional implementation of step S3103 can refer to the optional implementation of step S2105 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0559] Step S3104: The terminal receives the first information sent by the first cell.

[0560] In some embodiments, the optional implementation of step S3104 can refer to the optional implementation of step S2106 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0561] Step S3105: Maintain synchronization with the first cell based on the second signal or control signaling.

[0562] In some embodiments, the optional implementation of step S3105 can refer to the optional implementation of step S2108 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0563] Step S3106: The RRC connection between the terminal and the first cell is released.

[0564] In some embodiments, the optional implementation of step S3104 can refer to the optional implementation of step S2109 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0565] Step S3107: The terminal sends an RRC connection recovery request to the second cell.

[0566] In some embodiments, the optional implementation of step S3107 can refer to the optional implementation of step S2110 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0567] The synchronization method according to the embodiments of the present disclosure may include at least one of steps S3101 to S1207. For example, steps S3102 to S3103 may be implemented as independent embodiments, steps S3103 to S3105 may be implemented as independent embodiments, step S3103 combined with step S3105 may be implemented as independent embodiments, and steps S3106 to S3107 may be implemented as independent embodiments, but the present disclosure is not limited thereto.

[0568] In some embodiments, step S3101 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understandable that the current serving cell of the terminal or the target cell to be switched can directly obtain the first capability information of the terminal from the core network device without the terminal sending it.

[0569] In some embodiments, step S3104 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal may determine the first information according to the protocol, or the terminal may receive the first information sent by the second cell without the first cell sending it.

[0570] In some embodiments, step S3105 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal can maintain synchronization with the first cell based on the first signal sent by the second cell, without having to send the second signal or control signaling based on the first cell.

[0571] FIG3b is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG3b , the embodiment of the present disclosure relates to a synchronization method, which is executed by terminal 101 and includes:

[0572] Step S3201: The terminal sends first capability information.

[0573] In some embodiments, the terminal sends the first capability information to the third cell.

[0574] In some embodiments, the optional implementation of step S3201 can refer to the optional implementation of step S2101 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0575] Step S3202: The terminal receives a first message sent by the third cell.

[0576] In some embodiments, the third cell sends the first message to the terminal.

[0577] In some embodiments, the optional implementation of step S3202 can refer to the optional implementation of step S2104 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0578] Step S3203: The terminal switches to the first cell.

[0579] In some embodiments, the terminal is handed over from the third cell to the first cell.

[0580] In some embodiments, the optional implementation of step S3203 can refer to the optional implementation of step S2105 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0581] Step S3204: The terminal receives the first information sent by the second cell.

[0582] In some embodiments, the optional implementation of step S3204 can refer to the optional implementation of step S2206 in Figure 2b and other related parts of the embodiment involved in Figure 2b, which will not be repeated here.

[0583] Step S3205: Based on the first signal, maintain synchronization with the first cell.

[0584] In some embodiments, the optional implementation of step S3205 can refer to the optional implementation of step S2208 in Figure 2b and other related parts of the embodiment involved in Figure 2b, which will not be repeated here.

[0585] Step S3206: The RRC connection between the terminal and the first cell is released.

[0586] In some embodiments, the optional implementation of step S3206 can refer to the optional implementation of step S2109 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0587] Step S3207: The terminal sends an RRC connection recovery request to the second cell.

[0588] In some embodiments, the optional implementation of step S3207 can refer to the optional implementation of step S2110 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0589] The synchronization method involved in the embodiments of the present disclosure may include at least one of steps S3201 to S3207. For example, steps S3202 to S3203 may be implemented as independent embodiments, steps S3203 to S3205 may be implemented as independent embodiments, step S3203 combined with step S3205 may be implemented as independent embodiments, and steps S3206 to S3207 may be implemented as independent embodiments, but are not limited thereto.

[0590] In some embodiments, step S3201 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understandable that the current serving cell of the terminal or the target cell to be switched can directly obtain the first capability information of the terminal from the core network device without the terminal sending it.

[0591] In some embodiments, step S3204 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal may determine the first information according to the protocol, or the terminal may directly receive the first information sent by the first cell without the need for the second cell to send it.

[0592] In some embodiments, step S3205 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal may maintain synchronization with the first cell based on the second signal or control signaling sent by the first cell, without relying on the first signal.

[0593] FIG3c is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG3c, the embodiment of the present disclosure relates to a synchronization method, which is executed by terminal 101 and includes:

[0594] Step S3301: The terminal maintains synchronization with the first cell according to the first information.

[0595] In some embodiments, the first cell is a serving cell of the terminal.

[0596] In some embodiments, the first cell does not send one or more of the following:

[0597] Synchronization signal broadcast channel block SSB;

[0598] One or more system information blocks (SIBs);

[0599] Paging message.

[0600] In some embodiments, the first cell does not send SSB, SIB and paging messages.

[0601] In some embodiments, the first information is determined by a protocol;

[0602] or,

[0603] The first information is sent by the first cell to the terminal;

[0604] or,

[0605] The first information is sent to the terminal by a second cell; wherein the second cell is different from the first cell.

[0606] In some embodiments, the second cell sends one or more of the following:

[0607] Synchronization signal broadcast channel block SSB;

[0608] One or more system information blocks (SIBs);

[0609] Paging message.

[0610] In some embodiments, the first information includes at least one of the following:

[0611] A first configuration is configured for the terminal to maintain synchronization with the first cell according to a first signal sent by the second cell;

[0612] The control signaling includes: second information used to maintain synchronization between the terminal and the first cell;

[0613] The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

[0614] In some embodiments, the second signal is also used for radio resource management RRM of the terminal.

[0615] In some embodiments, the first signal includes: a synchronization signal broadcast channel block SSB.

[0616] In some embodiments, the second signal includes at least one of the following:

[0617] Channel state information CSI-reference signal RS;

[0618] Tracking reference signal TRS;

[0619] A third signal, wherein the third signal is different from the SSB, the CSI-RS and / or the TRS and is a signal for maintaining synchronization between the terminal and the first cell.

[0620] In some embodiments, the third signal also carries system frame information.

[0621] In some embodiments, the first configuration includes at least one of the following:

[0622] Measurement period;

[0623] Measurement window;

[0624] Measurement bias;

[0625] cell information of the second cell;

[0626] Timing information is used by the terminal to determine the downlink timing of the first cell.

[0627] In some embodiments, the timing information includes at least one of the following:

[0628] downlink timing information of the second cell;

[0629] The timing offset between the second cell and the first cell.

[0630] In some embodiments, the second configuration includes at least one of the following:

[0631] Measurement period;

[0632] Measurement window;

[0633] Measurement bias;

[0634] Measure the signal.

[0635] In some embodiments, the first configuration further includes:

[0636] SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the second cell.

[0637] In some embodiments, the second configuration further includes:

[0638] SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the first cell.

[0639] In some embodiments, the control signaling includes:

[0640] Downlink control information DCI.

[0641] In some embodiments, the second information includes: system frame information.

[0642] In some embodiments, the downlink control information DCI is scrambled by a radio network temporary identifier RNTI.

[0643] In some embodiments, the radio network temporary identifier (RNTI) includes one of the following:

[0644] A first RNTI, wherein the first RNTI includes: a cell radio network temporary identifier C-RNTI;

[0645] Second RNTI; the second RNTI is different from the first RNTI.

[0646] In some embodiments, the method further comprises:

[0647] Before the first cell serves as the serving cell of the terminal, the first cell sends first capability information of the terminal; wherein the first capability information is used to determine whether the first cell can serve as the serving cell of the terminal.

[0648] In some embodiments, the first capability information indicates at least one of the following:

[0649] whether the terminal supports the first cell as a primary cell;

[0650] Whether the terminal supports the first cell as a secondary cell of the terminal.

[0651] In some embodiments, the method further comprises:

[0652] The terminal supports the first cell as the primary cell, and the terminal switches to the first cell.

[0653] In some embodiments, the terminal supports the first cell as the primary cell, and the terminal switches to the first cell, including:

[0654] The first cell supports being a primary cell, and the terminal supports the first cell as a primary cell, and the terminal switches to the first cell.

[0655] In some embodiments, the first cell is not supported as a primary cell, and the terminal does not switch to the first cell.

[0656] In some embodiments, before switching to the first cell, a first message sent by a third cell is received; wherein the first message includes at least one of the following:

[0657] identification information of the first cell;

[0658] cell information of the first cell;

[0659] a timing offset between the first cell and the third cell;

[0660] a communication configuration of the first cell;

[0661] the first configuration;

[0662] The second configuration.

[0663] In some embodiments, the communication configuration includes at least one of the following:

[0664] Radio bearer RB configuration;

[0665] Protocol Data Unit (PDU) session configuration.

[0666] In some embodiments, the method further comprises:

[0667] The RRC connection between the terminal and the first cell is released, and the terminal sends an RRC connection recovery request to the second cell; the RRC connection recovery request indicates that the anchor cell of the terminal is the first cell.

[0668] FIG4a is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG4a , the embodiment of the present disclosure relates to a synchronization method, which is executed by the first access network device 1021 and includes:

[0669] Step S4101: The first cell receives a second message sent by the third cell;

[0670] In some embodiments, the third cell sends the second message to the first cell.

[0671] In some embodiments, the optional implementation of step S4101 can refer to the optional implementation of step S2102 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0672] Step S4102: The first cell sends a third message to the third cell.

[0673] In some embodiments, the first cell accepts the terminal switching to the first cell, and the first cell sends a third message to the third cell.

[0674] In some embodiments, the optional implementation of step S4102 can refer to the optional implementation of step S2103 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0675] Step S4103: The first cell sends the first information.

[0676] In some embodiments, the first cell sends the first information to the terminal.

[0677] In some embodiments, the first cell sends the first information to the second cell.

[0678] In some embodiments, the optional implementation of step S4103 can refer to the optional implementation of step S2106 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0679] Step S4104: The first cell sends a second signal or control signaling.

[0680] In some embodiments, the optional implementation of step S4104 can refer to the optional implementation of step S2107 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0681] Step S4105: The first cell releases the RRC connection with the terminal.

[0682] In some embodiments, the optional implementation of step S4105 can refer to the optional implementation of step S2109 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0683] Step S4106: The first cell receives the terminal context request message sent by the second cell.

[0684] In some embodiments, the second cell sends a terminal context request message to the first cell.

[0685] In some embodiments, the optional implementation of step S4106 can refer to the optional implementation of step S2111 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0686] Step S4107: The first cell sends the access layer AS context information of the terminal to the second cell.

[0687] In some embodiments, the optional implementation of step S4107 can refer to the optional implementation of step S2112 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0688] The synchronization method according to the embodiments of the present disclosure may include at least one of steps S4101 to S4107. For example, steps S4101 to S4102 may be implemented as independent embodiments, steps S4103 to S4104 may be implemented as independent embodiments, and steps S4104 to S4106 may be implemented as independent embodiments, but are not limited thereto.

[0689] In some embodiments, step S4103 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understandable that the terminal may determine the first information according to the protocol, without the need for the first cell to send it.

[0690] In some embodiments, step S4104 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal can maintain synchronization with the first cell based on the first signal sent by the second cell, without the first cell sending a second signal or control signaling.

[0691] In some embodiments, steps S4105 and S4106 are optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that if the anchor cell of the terminal is not the first cell, the second cell does not need to obtain the terminal context request message from the first cell.

[0692] FIG4 b is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG4 b , the embodiment of the present disclosure relates to a synchronization method, which is executed by the first access network device 1021 and includes:

[0693] Step S4201: The first cell sends the first information.

[0694] In some embodiments, the first information is used for the terminal to maintain synchronization with the first cell.

[0695] In some embodiments, the first cell is a serving cell of the terminal.

[0696] In some embodiments, the first cell does not send one or more of the following:

[0697] Synchronization signal broadcast channel block SSB;

[0698] One or more system information blocks (SIBs);

[0699] Paging message.

[0700] In some embodiments, the first cell does not send SSB, SIB and paging messages.

[0701] In some embodiments, the first cell sends the first information, including at least one of the following:

[0702] The first cell sends the first information to the terminal;

[0703] The first cell sends the first information to the second cell; the second cell is a neighboring cell of the first cell.

[0704] In some embodiments, the second cell sends one or more of the following:

[0705] Synchronization signal broadcast channel block SSB;

[0706] One or more system information blocks (SIBs);

[0707] Paging message.

[0708] In some embodiments, the first information includes at least one of the following:

[0709] A first configuration is configured for the terminal to maintain synchronization with the first cell according to a first signal sent by the second cell;

[0710] The control signaling includes: second information used to maintain synchronization between the terminal and the first cell;

[0711] The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

[0712] In some embodiments, the second signal is also used for radio resource management RRM of the terminal.

[0713] In some embodiments, the first signal includes: a synchronization signal broadcast channel block SSB.

[0714] In some embodiments, the second signal includes at least one of the following: channel state information CSI-reference signal RS;

[0715] Tracking reference signal TRS;

[0716] A third signal, wherein the third signal is different from the SSB, the CSI-RS and / or the TRS and is a signal for maintaining synchronization between the terminal and the first cell.

[0717] In some embodiments, the first configuration includes at least one of the following:

[0718] Measurement period;

[0719] Measurement window;

[0720] Measurement bias;

[0721] cell information of the second cell;

[0722] Timing information is used by the terminal to determine the downlink timing of the first cell.

[0723] In some embodiments, the timing information includes at least one of the following:

[0724] downlink timing information of the second cell;

[0725] The timing offset between the second cell and the first cell.

[0726] In some embodiments, the second configuration includes at least one of the following:

[0727] Measurement period;

[0728] Measurement window;

[0729] Measurement bias;

[0730] Measure the signal.

[0731] In some embodiments, the first configuration further includes:

[0732] SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the second cell.

[0733] In some embodiments, the second configuration further includes:

[0734] SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the first cell.

[0735] In some embodiments, the control signaling includes at least one of the following:

[0736] The control signaling sent periodically;

[0737] The control signaling sent based on the request of the terminal;

[0738] The control signaling sent based on the triggering of a preset event.

[0739] In some embodiments, the preset event includes at least one of the following:

[0740] a measurement event of the terminal;

[0741] The transmission scheduling feedback event of the terminal.

[0742] In some embodiments, the control signaling includes:

[0743] Downlink control information DCI.

[0744] In some embodiments, the second information includes: system frame information.

[0745] In some embodiments, the downlink control information DCI is scrambled by a radio network temporary identifier RNTI.

[0746] In some embodiments, the radio network temporary identifier (RNTI) includes one of the following:

[0747] A first RNTI, wherein the first RNTI includes: a cell radio network temporary identifier C-RNTI;

[0748] Second RNTI; the second RNTI is different from the first RNTI.

[0749] In some embodiments, the method further comprises:

[0750] Obtain first capability information of the terminal; wherein the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal.

[0751] In some embodiments, the acquiring the first capability information of the terminal includes at least one of the following:

[0752] Acquire first capability information of the terminal from a core network device;

[0753] Receive the first capability information of the terminal sent by the third cell.

[0754] In some embodiments, the first capability information indicates at least one of the following:

[0755] whether the terminal supports the first cell as a primary cell;

[0756] Whether the terminal supports the first cell as a secondary cell of the terminal.

[0757] In some embodiments, the method further comprises:

[0758] receiving a second message sent by a third cell, wherein the second message is used to indicate whether the terminal supports handover to the first cell;

[0759] Accept the terminal switching to the first cell, and send a third message to the third cell; the third message is used by the third cell to send the first message to the terminal.

[0760] In some embodiments, the third message includes at least one of the following:

[0761] identification information of the first cell;

[0762] cell information of the first cell;

[0763] a timing offset between the first cell and the third cell;

[0764] a communication configuration of the first cell;

[0765] the first configuration;

[0766] The second configuration.

[0767] In some embodiments, the communication configuration includes at least one of the following:

[0768] Radio bearer RB configuration;

[0769] Protocol Data Unit (PDU) session configuration.

[0770] FIG4c is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG4c, the embodiment of the present disclosure relates to a synchronization method, which is executed by the second access network device 1022. The method includes:

[0771] Step S4301: The second cell sends first information to the terminal.

[0772] In some embodiments, the terminal receives first information sent by the second cell.

[0773] In some embodiments, the second cell receives the first information sent by the first cell and sends the first information to the terminal.

[0774] In some embodiments, the optional implementation of step S4301 can refer to the optional implementation of step S2206 in Figure 2b and other related parts of the embodiment involved in Figure 2b, which will not be repeated here.

[0775] Step S4302: The second cell sends a first signal.

[0776] In some embodiments, the optional implementation of step S4302 can refer to the optional implementation of step S2207 in Figure 2b and other related parts of the embodiment involved in Figure 2b, which will not be repeated here.

[0777] Step S4303: The second cell receives the RRC connection recovery request sent by the terminal.

[0778] In some embodiments, the optional implementation of step S4303 can refer to the optional implementation of step S2110 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0779] Step S4304: The second cell sends a terminal context request message to the first cell.

[0780] In some embodiments, the optional implementation of step S4304 can refer to the optional implementation of step S2111 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0781] Step S4305: The second cell receives the access stratum AS context information of the terminal sent by the first cell.

[0782] In some embodiments, the optional implementation of step S4305 can refer to the optional implementation of step S2112 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0783] The synchronization method according to the embodiments of the present disclosure may include at least one of steps S4301 to S4305. For example, steps S4301 and S4302 may be implemented as independent embodiments, steps S4302 to S4305 may be implemented as independent embodiments, and steps S4303 and S4305 may be implemented as independent embodiments, but are not limited thereto.

[0784] In some embodiments, step S4301 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understandable that the first cell may directly send the first information to the terminal without the need for the second cell to send the first information.

[0785] In some embodiments, step S4302 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that the terminal can maintain synchronization with the first cell based on the second signal or control signaling sent by the first cell without the second cell sending the first signal.

[0786] In some embodiments, steps S4303 and S4304 are optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that if the anchor cell of the terminal is not the first cell, the second cell does not need to obtain the terminal context request message from the first cell.

[0787] FIG4 d is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG4 d , the embodiment of the present disclosure relates to a synchronization method, which is executed by the second access network device 1022 and includes:

[0788] Step S4401: The second cell sends first information to the terminal.

[0789] In some embodiments, the first information is used for the terminal to maintain synchronization with the first cell.

[0790] In some embodiments, the second cell is a neighboring cell of the first cell

[0791] In some embodiments, the first cell is a serving cell of the terminal.

[0792] In some embodiments, the first cell does not send one or more of the following:

[0793] Synchronization signal broadcast channel block SSB;

[0794] One or more system information blocks (SIBs);

[0795] Paging message.

[0796] In some embodiments, the first cell does not send SSB, SIB and paging messages.

[0797] In some embodiments, the first information includes at least one of the following:

[0798] A first configuration is configured for the terminal to maintain synchronization with the first cell according to a first signal sent by the second cell;

[0799] The control signaling includes: second information used to maintain synchronization between the terminal and the first cell;

[0800] The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

[0801] In some embodiments, the second cell sends one or more of the following:

[0802] Synchronization signal broadcast channel block SSB;

[0803] One or more system information blocks (SIBs);

[0804] Paging message.

[0805] In some embodiments, the second signal is also used for radio resource management RRM of the terminal.

[0806] In some embodiments, the first signal includes: a synchronization signal broadcast channel block SSB.

[0807] In some embodiments, the second signal includes at least one of the following:

[0808] Channel state information CSI-reference signal RS;

[0809] Tracking reference signal TRS;

[0810] A third signal, wherein the third signal is different from the SSB, the CSI-RS and / or the TRS and is a signal used to maintain synchronization between the terminal and the first cell.

[0811] In some embodiments, the third signal also carries system frame information.

[0812] In some embodiments, the first configuration includes at least one of the following:

[0813] Measurement period;

[0814] Measurement window;

[0815] Measurement bias;

[0816] cell information of the second cell;

[0817] Timing information is used by the terminal to determine the downlink timing of the first cell.

[0818] In some embodiments, the timing information includes at least one of the following:

[0819] downlink timing information of the second cell;

[0820] The timing offset between the second cell and the first cell.

[0821] In some embodiments, the second configuration includes at least one of the following:

[0822] Measurement period;

[0823] Measurement window;

[0824] Measurement bias;

[0825] Measure the signal.

[0826] In some embodiments, the first configuration further includes:

[0827] SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the second cell.

[0828] In some embodiments, the second configuration further includes:

[0829] SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the frequency layers in at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the first cell.

[0830] In some embodiments, the control signaling includes:

[0831] Downlink control information DCI.

[0832] In some embodiments, the second information includes: system frame information.

[0833] In some embodiments, the downlink control information DCI is scrambled by a radio network temporary identifier RNTI.

[0834] In some embodiments, the radio network temporary identifier (RNTI) includes one of the following:

[0835] A first RNTI, wherein the first RNTI includes: a cell radio network temporary identifier C-RNTI;

[0836] Second RNTI; the second RNTI is different from the first RNTI.

[0837] In some embodiments, the second cell includes:

[0838] Configuration-related information of a notification area RNA of a radio access network RAN; the configuration-related information includes: identifiers of one or more cells;

[0839] The configuration-related information does not include the identifier of the first cell.

[0840] In some embodiments, the method further comprises:

[0841] receiving an RRC connection recovery request sent by the terminal, wherein the RRC connection recovery request indicates that the anchor cell of the terminal is the first cell;

[0842] Sending a terminal context request message to the first cell; the terminal context request message is used to obtain access layer AS context information of the terminal.

[0843] FIG4e is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG4e , the embodiment of the present disclosure relates to a synchronization method, which is executed by the third access network device 1023 and includes:

[0844] Step S4501: The third cell obtains the first capability information of the terminal.

[0845] In some embodiments, the optional implementation of step S4501 can refer to the optional implementation of step S2101 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0846] Step S4502: The third cell sends a second message to the first cell.

[0847] In some embodiments, the optional implementation of step S4502 can refer to the optional implementation of step S2102 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0848] Step S4503: The third cell receives the third message sent by the first cell.

[0849] In some embodiments, the optional implementation of step S4503 can refer to the optional implementation of step S2103 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0850] Step S4504: The third cell sends a first message to the terminal.

[0851] In some embodiments, the optional implementation of step S4504 can refer to the optional implementation of step S2104 in Figure 2a and other related parts of the embodiment involved in Figure 2a, which will not be repeated here.

[0852] The synchronization method involved in the embodiment of the present disclosure may include at least one of steps S4501 to S4504. For example, step S4501 combined with steps S4502 and S4504 can be implemented as an independent embodiment, and step S4502 combined with steps S4503 and S4504 can be implemented as an independent embodiment, but the present invention is not limited thereto.

[0853] In some embodiments, step S4501 is optional, and one or more of these steps may be omitted or replaced in different embodiments. It is understood that, when the current serving cell of the terminal is the first cell, before the terminal needs to switch to another first cell, the current serving cell of the terminal does not need to obtain the first capability information of the terminal to know whether the terminal supports the first cell as the primary cell.

[0854] FIG4f is a flow chart of a synchronization method according to an embodiment of the present disclosure. As shown in FIG4f , the embodiment of the present disclosure relates to a synchronization method, which is executed by the third access network device 1023 and includes:

[0855] Step S4601: The third cell obtains the first capability information of the terminal.

[0856] In some embodiments, the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal.

[0857] In some embodiments, the third cell is a neighboring cell of the first cell.

[0858] In some embodiments, the first cell does not send one or more of the following:

[0859] Synchronization signal broadcast channel block SSB;

[0860] One or more system information blocks (SIBs);

[0861] Paging message.

[0862] In some embodiments, the first cell does not send SSB, SIB and paging messages.

[0863] In some embodiments, the third cell acquires the first capability information of the terminal, including at least one of the following:

[0864] Acquire first capability information of the terminal from a core network device;

[0865] Receive the first capability information sent by the terminal.

[0866] In some embodiments, the first capability information indicates at least one of the following:

[0867] whether the terminal supports the first cell as a primary cell;

[0868] Whether the terminal supports the first cell as a secondary cell of the terminal.

[0869] In some embodiments, the method further comprises:

[0870] Acquire cell-related information of the first cell, where the cell-related information is used to determine whether the first cell can serve as a primary cell;

[0871] Based on the first capability information and the cell-related information, a second message is sent to the first cell; the second message is used to indicate whether the terminal supports switching to the first cell.

[0872] In some embodiments, the cell-related information includes at least one of the following:

[0873] Cell type information;

[0874] Cell capability information, indicating whether the first cell supports being the primary cell.

[0875] In some embodiments, the method further comprises:

[0876] receiving a third message sent by the first cell;

[0877] A first message is sent to the terminal according to the third message; the first message is used to indicate whether the terminal can switch to the first cell.

[0878] In some embodiments, the method further comprises:

[0879] The terminal supports the first cell as the primary cell, and determines whether to accept handover of the terminal to the first cell according to cell-related information of the first cell;

[0880] or,

[0881] The terminal supports the first cell as the primary cell, and determines whether to accept handover of the terminal to the first cell according to a third message provided by the first cell.

[0882] In some embodiments, the terminal supports the first cell as the primary cell, and determines whether to accept handover of the terminal to the first cell according to cell-related information of the first cell, including:

[0883] The terminal supports the first cell as a primary cell and determines, based on the cell-related information, that the first cell supports being a primary cell, and determines to accept handover of the terminal to the first cell.

[0884] In some embodiments, the method further comprises:

[0885] The first cell does not support being a primary cell, and determines to reject handover of the terminal to the first cell.

[0886] In some embodiments, the first message includes at least one of the following:

[0887] identification information of the first cell;

[0888] cell information of the first cell;

[0889] a timing offset between the first cell and the third cell;

[0890] a communication configuration of the first cell;

[0891] First configuration;

[0892] Second configuration.

[0893] In some embodiments, the communication configuration includes at least one of the following:

[0894] Radio bearer RB configuration;

[0895] Protocol Data Unit (PDU) session configuration.

[0896] In some embodiments, the third cell includes:

[0897] Configuration-related information of a notification area RNA of a radio access network RAN; the configuration-related information includes: identifiers of one or more cells;

[0898] The configuration-related information does not include the identifier of the first cell.

[0899] FIG5 is an interactive diagram of a synchronization method according to an embodiment of the present disclosure. As shown in FIG5 , the embodiment of the present disclosure relates to a synchronization method for a communication system 100, and the method includes one of the following steps:

[0900] Step S5101: Before the terminal switches to the first cell, the third cell obtains the first capability information of the terminal.

[0901] In some embodiments, the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal.

[0902] In some embodiments, the third cell is a neighboring cell of the first cell.

[0903] Step S5102: After the terminal switches to the first cell, the first cell and / or the second cell sends first information;

[0904] In some embodiments, the second cell is a neighboring cell of the first cell.

[0905] Step S5103: The terminal keeps synchronization with the first cell according to the first information.

[0906] In some embodiments, the first cell does not send one or more of the following:

[0907] Synchronization signal broadcast channel block SSB;

[0908] One or more system information blocks (SIBs);

[0909] Paging message.

[0910] In some embodiments, the above method may include the methods of the above-mentioned communication system side, terminal side, access network equipment side, core network equipment side, etc., which will not be repeated here.

[0911] R15 introduces 5G technology. The energy consumption of 5G base stations is four times that of LTE base stations, so network energy saving is an important means for operators to reduce the cost of operating 5G systems.

[0912] In R16, a wake-up signal (WUS) is introduced to save energy for RRC connected (RRC_CONNECTED) terminals. A WUS signal duration is defined by an offset before the wake-up period (on duration) of the UE's connected C-discontinuous reception (DRX). During this WUS duration, the WUS signal, i.e., DCI 2-6, is sent, scrambled by the PS-RNTI, to indicate whether the terminal should wake up to monitor the PDCCH during the next UE C-DRX on duration, or to wake up.

[0913] In Release 17, a paging wake-up signal (WUS) was introduced to save energy for terminals in the RRC idle (RRC_IDLE) and RRC inactive (RRC_INACTIVE) states. This WUS, also known as the paging early indication (PEI), is sent at a certain time before the paging occasion (PO) to indicate whether the terminal is monitoring paging scheduling information at that PO. The PEI is DCI 2-7, scrambled using the PEI-RNTI.

[0914] In 5G Release 18, network energy conservation was initiated to reduce network energy consumption. When the network enters energy conservation mode (NES mode), cells periodically stop transmitting and / or receiving at regular intervals, a process known as cell DTX / DRX. However, the current standard stipulates that MIB, SIB, paging, and RACH can be transmitted and received. The four currently supported NES functions are as follows, each specified separately in the standard:

[0915] SSB-less SCell

[0916] cell DTX / DRX

[0917] Antenna port adaptation

[0918] ·PDSCH transmission power adaptation

[0919] Figure 6 is a schematic diagram illustrating different types of cell broadcast configurations according to an embodiment of the present disclosure. The concept of SSB / SIB1-less cells was proposed during the network energy-saving technology feasibility study (SI) phase. SSB / SIB1-less cells do not transmit SSBs, SIB1s, other SIBs, or paging, but can initiate a random access (RACH) process to SSB / SIB1-less cells. SSB / SIB1-less cells do not transmit SSBs, and SIB1s are broadcasted through an associated cell.

[0920] Example 1: How does an RRC_CONNECTED UE maintain time-frequency synchronization in an SSB / SIB1-less cell?

[0921] When the UE is in the RRC_CONNECTED state and there is a serving cell of the SSB / SIB1-less cell type, and the SSB / SIB1-less cell is a Pcell (Primary Cell) or there is only one serving cell.

[0922] To maintain time-frequency synchronization, the RRC_CONNECTED UE:

[0923] Option 1: The network side configures a measurement gap (i.e., measurement Gap) for the UE, and / or configures a target cell. The SSB measurement of the target cell is used to maintain time-frequency synchronization between the RRC_CONNECTED UE and the serving cell (i.e., SSB / SIB1-less cell). The measurement Gap is used as the Gap gap for the terminal to perform time-frequency synchronization measurement in the target cell. The measurement Gap is periodic, and the configuration parameters may include period, measurement duration, offset, etc. The timing of the measurement Gap refers to the downlink DL timing of the target cell. The configuration parameters of the target cell may include at least one of the following: the frequency of the cell, the physical cell identifier (PCI), the cell identifier, SSB-related configuration, such as period, the position of the SSB in a burst, etc.

[0924] It should be noted that the network side may correspond to the first cell of the present disclosure; the measurement gap may correspond to the first configuration of the present disclosure; and the target cell may correspond to the second cell of the present disclosure.

[0925] For example, the content of the SSB-related configuration is as follows:

[0926] It should be noted that ssb-PositionsInBurst can be the position of SSB in a burst set (Brust); inOneGroup can be the SSB index in the group, groupPresence can be the group index, and ssb-PeriodicityServingCell can be the transmission period for SSB.

[0927] Option 2: The network configures a Tracking Reference Signal (TRS) for the UE to maintain time and frequency synchronization with the SSB / SIB1-less cell. In this case, the system frame number (SFN) information cannot be obtained.

[0928] Option 3: The network configures the UE with a time-frequency synchronization signal to maintain synchronization with the SSB / SIB1-less cell. This signal can also be used to obtain the system frame number (SFN) information.

[0929] It should be noted that the time-frequency synchronization signal corresponds to the third signal of the present disclosure.

[0930] Option 4: The network indicates SFN information to the UE via downlink control information (DCI). This information can be periodic, event-triggered, or requested by the terminal. The DCI can be scrambled based on the C-RNTI or a newly defined RNTI used to obtain cell synchronization information.

[0931] It is worth noting that the above four solutions can be used in combination, the main purpose of which is to obtain time-frequency synchronization and obtain system frame number SFN information (used to determine timing relationships such as measurement Gap and SMTC).

[0932] Example 2: Downlink DL timing relationship of measurement gap, SMTC, etc. configured by RRC connected terminal (RRC_CONNECTED UE)

[0933] When the UE is in the RRC_CONNECTED state and there is a serving cell of the SSB / SIB1-less cell type, and the SSB / SIB1-less cell is a PCell or there is only one serving cell.

[0934] When configuring RRM measurements for a terminal, a measurement gap is configured, along with at least one SMTC configuration per frequency layer. The timing of the measurement gap and SMTC is referenced to the DL timing of the target cell configured on the network side, or based on the DL timing of the current serving cell. The SFN is acquired based on the solution in Example 1.

[0935] Example 3: How does an RRC_CONNECTED UE switch to an SSB / SIB 1-less cell and establish time-frequency synchronization?

[0936] First, after the terminal enters the RRC_CONNECTED state, it reports the UE capabilities to the base station, or after the UE enters the RRC_CONNECTED state, it obtains the UE capability information through the core network device (such as the access management function AMF), where the capability information includes a capability indication of whether the UE supports SSB / SIB1-less cell, or a capability indication of whether it supports switching to SSB / SIB1-less cell.

[0937] Secondly, before handover preparation (the base station initiates a handover request to the target cell), the current base station or current cell obtains the capability information or cell type information of the target base station or target cell, that is, whether the target base station or target cell is an SSB / SIB1-less cell, and / or whether it supports the capability of independently serving UEs.

[0938] If the terminal supports SSB / SIB1-less cells, or supports handover to SSB / SIB1-less cells, and the target cell also supports SSB / SIB1-less cells or the ability to independently serve the UE, the current base station sends a handover request message to the target cell to prepare for handover. The current base station sends a handover command to the terminal, and the handover command configuration is:

[0939] The identification information of the handover target cell, radio resource configuration information, radio bearer configuration information, etc. For example, the cell identification information may include the cell frequency, PCI, cell identifier, etc. The radio resource configuration information may include physical channel configuration information, and the radio bearer configuration information may include L2 protocol stack (such as SDAP, PDCP, RLC, MAC, etc.) configuration information, bearer DRB configuration information, PDU session configuration information, etc.

[0940] Switch to the target cell to obtain the target cell configuration information for synchronization and timing; for example, the cell frequency, PCI, cell ID, SSB related configuration, such as period, SSB position in a burst, etc. Is it the same as option 1 in solution 1?

[0941] The timing deviation between the target cell and the original cell; for example, the difference in SFNs, subframes, slots, or symbols.

[0942] Switch to the target cell to obtain a synchronization reference signal or command; for example, TRS and / or DCI. For details, refer to options 2, 3, and 4 in embodiment 1.

[0943] Example 4: RRC connected UE released to RRC idle state (RRC_IDLE) or RRC inactive state (RRC_INACTIVE)

[0944] When the UE is in the RRC_CONNECTED state and there is a serving cell of the SSB / SIB1-less cell type, and the SSB / SIB1-less cell is a primary cell (PCell) or there is only one serving cell.

[0945] The network side (that is, the SSB / SIB1-less cell) releases the terminal into the RRC_INACTIVE UE, and the SSB / SIB1-less cell is not configured in the RAN radio access network paging notification area, that is, the RNA does not contain any SSB / SIB1-less cell.

[0946] If an RRC_INACTIVE UE performs the RRC Resume Procedure, and the anchor base station (i.e., the base station that stores the UE AS (Access Stratum) context) is an SSB / SIB1-less cell, upon receiving a UE Context Request message from the target base station, the SSB / SIB1-less cell performs UE context migration to the target base station. When the terminal is in the idle or deactivated state, mobility management includes the cell selection or reselection process.

[0947] The embodiments of the present disclosure also provide an apparatus for implementing any of the above methods. For example, an apparatus is provided, comprising units or modules for implementing each step performed by a terminal in any of the above methods. For another example, another apparatus is provided, comprising units or modules for implementing each step performed by a network device (e.g., an access network device or a core network device) in any of the above methods.

[0948] It should be understood that the division of the various units or modules in the above devices is merely a division of logical functions. In actual implementation, they may be fully or partially integrated into a physical entity, or they may be physically separated. In addition, the units or modules in the device may be implemented in the form of a processor calling software: for example, the device includes a processor, the processor is connected to a memory, and the memory stores instructions. The processor calls the instructions stored in the memory to implement any of the above methods or implement the functions of the various units or modules of the above devices, wherein the processor is, for example, a general-purpose processor, such as a central processing unit (CPU) or a microprocessor, and the memory is a memory within the device or a memory outside the device. Alternatively, the units or modules in the device can be implemented in the form of hardware circuits, and the functions of some or all of the units or modules can be realized by designing the hardware circuits. The above-mentioned hardware circuits can be understood as one or more processors; for example, in one implementation, the above-mentioned hardware circuit is an application-specific integrated circuit (ASIC), which realizes the functions of some or all of the above units or modules by designing the logical relationship of the components in the circuit; for example, in another implementation, the above-mentioned hardware circuit can be realized by a programmable logic device (PLD). Taking a field programmable gate array (FPGA) as an example, it can include a large number of logic gate circuits, and the connection relationship between the logic gate circuits is configured by configuring the configuration file, thereby realizing the functions of some or all of the above units or modules. All units or modules of the above devices can be realized in the form of software called by the processor, or in the form of hardware circuits, or in part by the form of software called by the processor, and the rest by hardware circuits.

[0949] In the embodiments of the present disclosure, the processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction reading and execution capabilities, such as a central processing unit (CPU), a microprocessor, a graphics processing unit (GPU) (which can be understood as a microprocessor), or a digital signal processor (DSP); in another implementation, the processor can implement certain functions through the logical relationship of the hardware circuit, and the logical relationship of the above-mentioned hardware circuit is fixed or reconfigurable, such as a hardware circuit implemented by a processor as an application-specific integrated circuit (ASIC) or a programmable logic device (PLD), such as an FPGA. In a reconfigurable hardware circuit, the process of the processor loading a configuration document to implement the hardware circuit configuration can be understood as the process of the processor loading instructions to implement the functions of some or all of the above units or modules. In addition, it can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as a neural network processing unit (NPU), a tensor processing unit (TPU), a deep learning processing unit (DPU), etc.

[0950] Figure 7a is a schematic diagram of the structure of a terminal provided by an embodiment of the present disclosure. As shown in Figure 7a, terminal 101 includes: a processing module 1011; the processing module 1011 is configured to synchronize with the first cell based on the first information. Optionally, the processing module 1011 is used to execute the steps related to information processing performed by the terminal in any of the above synchronization methods, which are not repeated here. Optionally, terminal 101 also includes a fourth transceiver module, which is used to execute the steps related to sending and receiving performed by the terminal in any of the above methods, which are not repeated here.

[0951] Figure 7b is a schematic diagram of the structure of the first access network device provided by an embodiment of the present disclosure. As shown in Figure 7b, the first access network device 1021 includes: a first transceiver module 1021a, configured to send first information; the first information is used for the terminal to maintain synchronization with the first cell. Optionally, the first transceiver module 1021a is used to execute the steps related to information sending and receiving performed by the terminal in any of the above synchronization methods, which are not repeated here. Optionally, the first access network device 1021 also includes a processing module, and the above processing module is used to execute the steps related to processing performed by the terminal in any of the above methods, which are not repeated here.

[0952] Figure 7c is a schematic diagram of the structure of a second access network device provided in an embodiment of the present disclosure. As shown in Figure 7c, the second access network device 1022 includes a second transceiver module 1022a configured to transmit first information; the first information is used to synchronize the terminal with the first cell. The first transceiver module 1022a is configured to execute the steps related to information transmission and reception performed by the terminal in any of the above synchronization methods, and will not be further described here.

[0953] Figure 7d is a schematic diagram of the structure of a third access network device provided in an embodiment of the present disclosure. As shown in Figure 7d, the third access network device 1023 includes a third transceiver module 1023a configured to obtain first capability information of a terminal; this first capability information is used to determine whether a first cell can serve as a serving cell for the terminal. The third transceiver module 1023a is configured to execute the steps related to information transmission and reception performed by the terminal in any of the above synchronization methods, and will not be further described here.

[0954] Figure 8a is a schematic diagram of the structure of a communication device 8100 provided in an embodiment of the present disclosure. Communication device 8100 can be a network device (e.g., an access network device or a core network device), a terminal (e.g., a user device), a chip, a chip system, or a processor that supports a network device in implementing any of the above methods, or a chip, a chip system, or a processor that supports a terminal in implementing any of the above synchronization methods. Communication device 8100 can be used to implement the synchronization method described in the above method embodiments. For details, please refer to the description of the above method embodiments.

[0955] As shown in Figure 8a, the communication device 8100 includes one or more processors 8101. The processor 8101 can be a general-purpose processor or a dedicated processor, for example, a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, and the central processing unit can be used to control the communication device (such as a base station, a baseband chip, a terminal device, a terminal device chip, a DU or a CU, etc.), execute programs, and process program data. The processor 8101 is used to call instructions to enable the communication device 8100 to execute any of the above communication methods.

[0956] In some embodiments, the communication device 8100 further includes one or more memories 8102 for storing instructions. Optionally, all or part of the memories 8102 may be located outside the communication device 8100.

[0957] In some embodiments, the communication device 8100 further includes one or more transceivers 8103. When the communication device 8100 includes one or more transceivers 8103, the communication steps such as sending and receiving in the above method are performed by the transceiver 8103, and the other steps are performed by the processor 8101.

[0958] In some embodiments, a transceiver may include a receiver and a transmitter, which may be separate or integrated. Optionally, the terms transceiver, transceiver unit, transceiver, and transceiver circuit may be used interchangeably; the terms transmitter, transmitting unit, transmitter, and transmitting circuit may be used interchangeably; and the terms receiver, receiving unit, receiver, and receiving circuit may be used interchangeably.

[0959] Optionally, the communication device 8100 further includes one or more interface circuits 8104, which are connected to the memory 8102. The interface circuits 8104 can be used to receive signals from the memory 8102 or other devices, and can be used to send signals to the memory 8102 or other devices. For example, the interface circuits 8104 can read instructions stored in the memory 8102 and send the instructions to the processor 8101.

[0960] The communication device 8100 described in the above embodiment may be a network device or a terminal, but the scope of the communication device 8100 described in the present disclosure is not limited thereto, and the structure of the communication device 8100 may not be limited by FIG. 8a. The communication device may be an independent device or may be part of a larger device. For example, the communication device may be: (1) an independent integrated circuit IC, or a chip, or a chip system or subsystem; (2) a collection of one or more ICs, optionally, the above IC collection may also include a storage component for storing data or programs; (3) an ASIC, such as a modem; (4) a module that can be embedded in other devices; (5) a receiver, a terminal device, an intelligent terminal device, a cellular phone, a wireless device, a handheld device, a mobile unit, an in-vehicle device, a network device, a cloud device, an artificial intelligence device, etc.; (6) others, etc.

[0961] FIG8b is a schematic diagram of the structure of a chip 8200 provided in an embodiment of the present disclosure. If the communication device 8100 can be a chip or a chip system, please refer to the schematic diagram of the structure of the chip 8200 shown in FIG8b, but the present disclosure is not limited thereto.

[0962] The chip 8200 includes one or more processors 8201 , and the processor 8201 is used to call instructions so that the chip 8200 executes any of the above communication methods.

[0963] In some embodiments, chip 8200 further includes one or more interface circuits 8202, which are connected to memory 8203. Interface circuit 8202 can be used to receive signals from memory 8203 or other devices, and can be used to send signals to memory 8203 or other devices. For example, interface circuit 8202 can read instructions stored in memory 8203 and send the instructions to processor 8201. Optionally, the terms interface circuit, interface, transceiver pin, and transceiver are interchangeable.

[0964] In some embodiments, the chip 8200 further includes one or more memories 8203 for storing instructions. Alternatively, all or part of the memories 8203 may be outside the chip 8200.

[0965] The present disclosure also provides a storage medium having instructions stored thereon, which, when executed on the communication device 8100, causes the communication device 8100 to execute any of the above methods. Optionally, the storage medium is an electronic storage medium. Optionally, the storage medium is a computer-readable storage medium, but may also be a storage medium readable by other devices. Optionally, the storage medium may be a non-transitory storage medium, but may also be a transient storage medium.

[0966] The present disclosure further provides a program product, which, when executed by the communication device 8100, enables the communication device 8100 to perform any of the above communication methods. Optionally, the program product is a computer program product.

[0967] The present disclosure also provides a computer program, which, when executed on a computer, enables the computer to execute any one of the above communication methods.

[0968] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the invention that follow from the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0969] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A synchronization method, wherein: The method comprises: The terminal keeps synchronization with the first cell according to the first information; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following contents: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

2. The method according to claim 1, wherein: The first cell does not send SSB, SIB and paging messages.

3. The method according to claim 1 or 2, wherein: The first information is determined by a protocol; or, The first information is sent by the first cell to the terminal; or, The first information is sent to the terminal by a second cell; wherein the second cell is different from the first cell.

4. The method according to claim 3, wherein: The second cell sends one or more of the following: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

5. The method according to any one of claims 1 to 4, wherein: The first information includes at least one of the following: A first configuration, configured for the terminal to maintain synchronization with the first cell according to a first signal sent by the second cell; The control signaling includes: second information used for maintaining synchronization between the terminal and the first cell; The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

6. The method according to claim 5, wherein: The second signal is also used for radio resource management RRM of the terminal.

7. The method according to claim 5, wherein: The first signal includes: a synchronization signal broadcast channel block SSB.

8. The method according to claim 5, wherein: The second signal includes at least one of the following: Channel state information CSI-reference signal RS; Tracking reference signal TRS; A third signal, wherein the third signal is different from the SSB, the CSI-RS and / or the TRS and is a signal for maintaining synchronization between the terminal and the first cell.

9. The method according to claim 8, wherein: The third signal also carries system frame information.

10. The method according to claim 5, wherein: The first configuration includes at least one of the following: Measurement cycle; Measurement window; Measurement bias; cell information of the second cell; Timing information is used by the terminal to determine the downlink timing of the first cell.

11. The method according to claim 10, wherein: The timing information includes at least one of the following: Downlink timing information of the second cell; The timing deviation between the second cell and the first cell.

12. The method according to claim 5, wherein: The second configuration includes at least one of the following: Measurement cycle; Measurement window; Measurement bias; Measure the signal.

13. The method according to claim 10 or 11, wherein: The first configuration further includes: The SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the second cell.

14. The method according to claim 12, wherein: The second configuration further includes: The SSB measurement timing SMTC configuration and / or measurement interval configuration of each of the at least one frequency layer; wherein the timing information of the SMTC configuration and / or measurement interval configuration is determined based on the downlink timing information of the first cell.

15. The method according to any one of claims 5 to 14, wherein: The control signaling includes: Downlink control information DCI.

16. The method according to claim 15, wherein: The second information includes: system frame information.

17. The method according to claim 15 or 16, wherein: The downlink control information DCI is scrambled by a radio network temporary identifier RNTI.

18. The method according to claim 17, wherein: The radio network temporary identifier RNTI includes one of the following: A first RNTI, wherein the first RNTI includes: a cell radio network temporary identifier C-RNTI; Second RNTI; the second RNTI is different from the first RNTI.

19. The method according to any one of claims 5 to 18, wherein: The method further comprises: Before the first cell serves as a serving cell for the terminal, the first cell sends first capability information of the terminal; wherein the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal.

20. The method according to claim 19, wherein: The first capability information indicates at least one of the following: Whether the terminal supports the first cell as a primary cell; Whether the terminal supports the first cell as a secondary cell of the terminal.

21. The method according to claim 20, wherein: The method further comprises: The terminal supports the first cell as the primary cell, and the terminal switches to the first cell.

22. The method according to claim 21, wherein: The terminal supports the first cell as the primary cell, and the terminal switches to the first cell, including: The first cell supports being used as a primary cell, and the terminal supports the first cell as a primary cell, and the terminal switches to the first cell.

23. The method according to claim 21, wherein: The first cell does not support being a primary cell, and the terminal does not switch to the first cell.

24. The method according to any one of claims 20 to 22, wherein: The method further comprises: Before switching to the first cell, receiving a first message sent by the third cell; wherein the first message includes at least one of the following: identification information of the first cell; cell information of the first cell; a timing deviation between the first cell and the third cell; a communication configuration of the first cell; the first configuration; The second configuration.

25. The method according to claim 24, wherein: The communication configuration includes at least one of the following: Radio bearer RB configuration; Protocol Data Unit (PDU) session configuration.

26. The method according to any one of claims 1 to 25, wherein: The method further comprises: The RRC connection between the terminal and the first cell is released, and the terminal sends an RRC connection recovery request to the second cell; the RRC connection recovery request indicates that the anchor cell of the terminal is the first cell.

27. A synchronization method, wherein: The method comprises: The first cell sends first information; the first information is used for the terminal to maintain synchronization with the first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following contents: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

28. The method according to claim 27, wherein: The first information includes at least one of the following: A first configuration, configured for the terminal to maintain synchronization with the first cell according to a first signal sent by the second cell; The control signaling includes: second information used for maintaining synchronization between the terminal and the first cell; The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

29. The method according to claim 28, wherein: The second signal includes at least one of the following: a channel state information CSI-reference signal RS; Tracking reference signal TRS; A third signal, wherein the third signal is different from the SSB, the CSI-RS and / or the TRS and is used for the terminal and a signal to maintain synchronization with the first cell.

30. The method of claim 29, wherein: The method further comprises: Acquire first capability information of the terminal; wherein the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal.

31. The method according to claim 30, wherein: The acquiring the first capability information of the terminal includes at least one of the following: Acquire first capability information of the terminal from a core network device; Receive the first capability information of the terminal sent by the third cell.

32. The method according to claim 30 or 31, wherein: The first capability information indicates at least one of the following: Whether the terminal supports the first cell as a primary cell; Whether the terminal supports the first cell as a secondary cell of the terminal.

33. The method according to any one of claims 30 to 32, wherein: The method further comprises: receiving a second message sent by a third cell; the second message is used to indicate whether the terminal supports switching to the first cell; Accept the terminal switching to the first cell, and send a third message to the third cell; the third message is used by the third cell to send the first message to the terminal.

34. A method according to any one of claims 28 to 33, wherein: The method further comprises: receiving a terminal context request message sent by the second cell; the terminal context request message is sent by the second cell after receiving an RRC connection recovery request message sent by the terminal; The stored access layer AS context information of the terminal is sent to the second cell.

35. A synchronization method, wherein: The method comprises: The second cell sends first information to the terminal; the first information is used for the terminal to maintain synchronization with the first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following contents: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

36. The method of claim 35, wherein: The first information includes at least one of the following: A first configuration, configured for the terminal to maintain synchronization with the first cell according to a first signal sent by the second cell; The control signaling includes: second information used for maintaining synchronization between the terminal and the first cell; The second configuration is used for the terminal to maintain synchronization with the first cell according to a second signal sent by the first cell.

37. The method of claim 36, wherein: The second cell sends one or more of the following: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

38. A method according to any one of claims 35 to 37, wherein: The second cell includes: Configuration related information of a notification area RNA of a radio access network RAN; the configuration related information includes: identification of one or more cells; The configuration-related information does not include an identifier of the first cell.

39. The method according to any one of claims 35 to 37, wherein: The method further comprises: receiving an RRC connection recovery request sent by the terminal; the RRC connection recovery request indicates that the anchor cell of the terminal is the first cell; Sending a terminal context request message to the first cell; the terminal context request message is used to obtain access layer AS context information of the terminal.

40. A synchronization method, wherein: The method comprises: The third cell acquires first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal; The first cell does not send one or more of the following: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

41. The method of claim 40, wherein: The first cell does not send SSB, SIB and paging messages.

42. The method according to claim 40 or 41, wherein: The third cell acquires the first capability information of the terminal, including at least one of the following: Acquire first capability information of the terminal from a core network device; Receive the first capability information sent by the terminal.

43. The method according to any one of claims 40 to 42, wherein: The first capability information indicates at least one of the following: Whether the terminal supports the first cell as a primary cell; Whether the terminal supports the first cell as a secondary cell of the terminal.

44. The method according to any one of claims 40 to 42, wherein: The method further comprises: Acquire cell-related information of the first cell; the cell-related information is used to determine whether the first cell can serve as a primary cell; Based on the first capability information and the cell-related information, a second message is sent to the first cell; the second message is used to indicate whether the terminal supports switching to the first cell.

45. The method of claim 44, wherein: The method further comprises: receiving a third message sent by the first cell; A first message is sent to the terminal according to the third message; the first message is used to indicate whether the terminal can switch to the first cell.

46. ​​The method of claim 45, wherein: The method further comprises: The terminal supports the first cell as the primary cell, and determines whether to accept handover of the terminal to the first cell according to the cell related information of the first cell; or, The terminal supports the first cell as the primary cell, and determines whether to accept handover of the terminal to the first cell according to a third message provided by the first cell.

47. The method according to claim 45 or 46, wherein: The first message includes at least one of the following: identification information of the first cell; cell information of the first cell; a timing deviation between the first cell and the third cell; a communication configuration of the first cell; First configuration; Second configuration.

48. A synchronization method, wherein: The method comprises: Before the terminal switches to the first cell, the third cell acquires first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell for the terminal; After the terminal switches to the first cell, the first cell and / or the second cell sends first information; the terminal keeps synchronization with the first cell according to the first information; the first cell does not send one or more of the following contents: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

49. A terminal, wherein: The terminal comprises: The processing module is configured to keep synchronization with a first cell according to the first information; the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following contents: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

50. A first access network device, wherein: The first access network device includes: The first transceiver module is configured to send first information; the first information is used for the terminal to keep synchronization with the first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following contents: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

51. A second access network device, wherein: The second access network device includes: The second transceiver module is configured to send first information; the first information is used for the terminal to maintain synchronization with the first cell; wherein the first cell is a serving cell of the terminal, and the first cell does not send one or more of the following contents: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

52. A third access network device, wherein: The third access network device comprises: A third transceiver module is configured to obtain first capability information of the terminal; the first capability information is used to determine whether the first cell can serve as a serving cell of the terminal; The first cell does not send one or more of the following: Synchronization signal broadcast channel block SSB; One or more system information blocks SIB; Paging message.

53. A communication system, wherein: The communication system includes a terminal, a first access network device, a second access network device and a third access network device; the terminal is configured to implement the synchronization method described in any one of claims 1 to 26, the first access network device is configured to implement the synchronization method described in any one of claims 27 to 34, the second access network device is configured to implement the synchronization method described in any one of claims 35 to 39, and the third access network device is configured to implement the synchronization method described in any one of claims 40 to 47.

54. A communication device, wherein: The communication device comprises: one or more processors; The processor is used to call instructions to enable the communication device to execute the synchronization method described in any one of claims 1 to 26, claims 27 to 34, claims 35 to 39, or claims 40 to 47.

55. A storage medium, wherein: The storage medium stores instructions, which, when executed on a communication device, enable the communication device to execute the synchronization method described in any one of claims 1 to 26, claims 27 to 34, claims 35 to 39, or claims 40 to 47.

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