Cell measurement evaluation and reselection method and system

Abstract

The invention discloses a cell measurement evaluation and reselection method. The terminal autonomously constructs the neighbor relation according to the historically received service cell SIB, the historically received service cell SIB after autonomously constructing the neighbor relation, the historically received RRC message and pre-written system information; the method comprises the following steps of: firstly extracting frequency point information by a terminal, then adding a pilot frequency measurement frequency point, an inter-system measurement frequency point and a reselection priority field which do not exist originally in an effective version of a current service cell SIB according to the extracted frequency point, or modifying the pilot frequency measurement frequency point and the inter-system measurement frequency point which exist originally to set the reselection priority field for the pilot frequency measurement frequency point and the inter-system measurement frequency point; therefore, the terminal can timely initiate cell reselection or reduce power consumption. According to the invention, the terminal autonomously constructs the neighbor cell, and the opportunity of carrying out additional cell measurement, reselection condition evaluation and reselection by the terminal is increased.

Description

Technical Field

[0001] This application relates to a mobile communication technology, and more particularly to a cell measurement, evaluation, and reselection method. Background Technology

[0002] The sixth-generation (6G) mobile communication technology faces a series of technical challenges in achieving seamless integration of non-terrestrial networks (NTN) and terrestrial networks (TN), especially in terms of protocol compatibility.

[0003] Typically, when a terminal is in idle or connected mode, it assesses the signal status of surrounding cells based on measured SSB (Synchronization Signal / PBCH block) signal strength and quality, and selects or reselects a cell with better signal quality and a more suitable location for camping according to protocol guidelines, thereby optimizing network connectivity and user experience. In mobile communication network architectures where NTN and TN coexist, optimizing terminal mobility and improving user experience presents technical challenges.

[0004] NTN has the following characteristics. First, NTN satellites are constantly moving rapidly. Compared to the movement of the satellites, the movement of the terminal is negligible. Except for geostationary satellites, other satellites leave the current geographical area periodically. Second, there is a near-far effect. When NTN satellites are at far and near ends, the strength and quality of SSB signals measured by the terminal change little. However, in the center and edge of a TN cell, the strength and quality of SSB signals measured by the terminal change significantly. Traditional TN measurement indicators may not meet the needs of NTN cell selection and reselection. Based on the characteristics of NTN, the protocol specification has added many features to cell measurement and reselection, such as time-based measurement, location-based measurement, and the option to skip TN measurements. Given the differences between NTN and TN, there is still room for optimization by the terminal in areas such as inter-frequency and inter-system measurement evaluation and cell reselection. For example, this could be achieved by measuring TN inter-frequency signals within NTN cells and by technologies for saving and utilizing historically received system information.

[0005] In mobile communication network architectures where NTN and TN coexist, the rapid movement of NTN cells means that NTN neighbor cell relationships change in real time. This implies that system information related to measurement and cell reselection may also change in real time. Furthermore, due to differences in mobile operators, information exchange between NTN and TN cells from different operators may be inaccurate and incomplete, making it impossible to obtain real-time neighbor cell relationships and optimize network system information parameters. For example, in regenerative payloads architectures, NTN base stations and some core network functional components are located on satellites, and the locations of NTN base stations change in real time, potentially leading to a lack of timely neighbor cell information exchange with TN base stations on the ground. Although terminals can receive broadcast system information, request system information using RRCSystemInfoRequest, or request system information using DedicatedSIBRequest, the neighbor cell information configuration contained in this system information is controlled by the base station, and the terminal cannot independently decide which type of neighbor cells to obtain. For example, a TN base station may not indicate the existence of the SIB19 field. The SIB19 field contains satellite auxiliary information for NTN access, while the system information obtained through broadcast reception, RRC system information request, and dedicated SIB request is for the system information indicated by the base station. This means that terminals camped in a TN cell cannot obtain the NTN neighbor cell field. Summary of the Invention

[0006] The technical problem to be solved by this application is: how to measure, evaluate and reselect cells in a mobile communication network in the context of real-time changes in the neighbor cell relationship of NTN.

[0007] To address the aforementioned technical problems, this application proposes a cell measurement assessment and reselection method, comprising the following steps: Step S11: The terminal accesses and camps on a new cell, receiving SIB1 of that cell; if SIB1 of the cell indicates the existence of an SIB with a system information broadcast status of "broadcasting", the terminal receives the broadcasting SIB and proceeds to step S12; otherwise, it directly proceeds to step S12. Step S12: The terminal determines whether to receive the remaining SIBs of the cell other than SIB1; if yes, the terminal requests and receives the required SIBs according to the indication of SIB1 of the cell, and then proceeds to step S13; if no, it directly proceeds to step S13. In steps S11 and S12, the terminal also stores the valid version of the received current serving cell SIB and the RRC messages of the current serving cell other than the SIB; and when camping on the current serving cell, it stores the valid version of the previous serving cell SIB in the historically received serving cell SIBs and the RRC messages of the previous serving cell other than the SIB in the historically received RRC messages. Step S13: The terminal autonomously constructs neighbor cell relationships based on the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing neighbor cell relationships, the historically received RRC messages, and pre-written system information. This means that the terminal first extracts frequency point information, and then, based on the extracted frequency points, adds previously non-existent inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority fields to the effective version of the current serving cell SIB, or modifies the existing inter-frequency measurement frequency points and inter-system measurement frequency points to set reselection priority fields. The purpose of adding or modifying all fields is to enable the terminal to initiate cell reselection in a timely manner or reduce power consumption. After the terminal autonomously constructs neighbor cell relationships, the effective version of the current serving cell SIB becomes the effective version of the SIB after autonomously constructing neighbor cell relationships. When the terminal camps on a serving cell, it stores the effective version of the SIB after autonomously constructing neighbor cell relationships into the historically received serving cell SIB after autonomously constructing neighbor cell relationships. Step S14: The terminal periodically measures the SSB signal strength and quality of the autonomously constructed neighbor cells. Step S15: The terminal determines whether there are any neighbor cells that meet the reselection conditions. If a neighboring cell meets the reselection criteria, it is selected as a reselection candidate cell, and the process proceeds to step S16. If no neighboring cell meets the reselection criteria, and the current serving cell still meets the camping criteria, the process returns to step S14 to continue measurement. If no neighboring cell meets the reselection criteria, and the current serving cell does not meet the camping criteria, but there are one or more NTN neighboring cells that do not meet the reselection criteria and whose remaining service time has not expired, these neighboring cells are considered to meet the reselection criteria, and they are selected as reselection candidate cells, and the process proceeds to step S16.Step S16: The terminal initiates a reselection to the cell with the highest ranking among the reselection candidate cells according to the protocol. If the reselection is successful, return to step S11. If the reselection fails, the terminal remains in the current serving cell and returns to step S14 to continue the measurement.

[0008] Further, in step S12, when the cell is a TN cell, the terminal requests and receives system information related to measurement evaluation and cell reselection for the NTN cell from the cell's base station, including SIB2, SIB3, SIB4, SIB5, SIB19, SIB25, or neighbor cell relationships contained in these SIBs. When the cell is an NTN cell, the terminal requests and receives system information related to measurement evaluation and cell reselection for the TN cell from the cell's base station, including SIB2, SIB3, SIB4, SIB5, SIB19, SIB25, or neighbor cell relationships contained in these SIBs.

[0009] Further, in step S13, the frequency point information extracted by the terminal includes any one or more of the following: the frequency point indicated by the SIB4 neighbor list of a cell in the historically received serving cell SIB; the frequency point indicated by the SIB4 neighbor list of a cell in the historically received serving cell SIB after the self-constructed neighbor relationship; the measurement object of a certain RRC reconfiguration message or the redirection frequency point of an RRC release message in the historically received RRC messages, or the frequency point indicated by the SIB1 message matched by the PLMN; the frequency point indicated by the dedicated SIB19 information of the RRC reconfiguration message in the historically received RRC messages; and the frequency point indicated in the pre-written system information.

[0010] Further, in step S13, the terminal sets a reselection priority for newly added or modified inter-frequency measurement frequency points and inter-system measurement frequency points, including the following: First, if the terminal's current camping cell is a TN cell, and the newly added or modified inter-frequency measurement frequency points and inter-system measurement frequency points include NTN frequency points, and the signal strength of the TN cell is higher than a threshold indicating a relatively good signal quality level for the TN cell, then the reselection priority of the NTN frequency points is set to low priority. Second, if the terminal's current camping cell is a TN cell, and the newly added or modified inter-frequency measurement frequency points and inter-system measurement frequency points include NTN frequency points, and the signal strength of the TN cell is lower than a threshold indicating a relatively poor signal quality level for the TN cell, and the terminal is located in the edge area of ​​the TN cell, then the reselection priority of the NTN frequency points is set to high priority. Third, if the terminal's current camping cell is a TN cell, and the newly added or modified inter-frequency measurement frequency points and inter-system measurement frequency points include NTN frequency points, and the terminal has already obtained the SIB19 or dedicated SIB19 of the NTN neighboring cell. In the first scenario, location parameters exist in the SIB19 or dedicated SIB19 of the NTN neighboring cell. If the terminal does not meet either the time or location restrictions of the NTN neighboring cell, the reselection priority of that NTN neighboring cell is set to low priority. If the terminal meets both the time and location restrictions of the NTN neighboring cell, the reselection priority of that NTN neighboring cell is set to high priority. In the second scenario, location parameters do not exist in the SIB19 or dedicated SIB19 of the NTN neighboring cell. If the terminal does not meet the time restrictions of the NTN neighboring cell, the reselection priority of that NTN neighboring cell is set to low priority. If the terminal meets the time restrictions of the NTN neighboring cell, the reselection priority of that NTN neighboring cell is set to high priority. Fourthly, if the terminal's currently camped cell is an NTN cell, and newly added or modified inter-frequency measurement points or inter-system measurement points include TN frequencies, if the uplink or downlink rate of the NTN cell is low, the reselection priority of the TN frequency is set to high priority.

[0011] Furthermore, in step S13, the terminal's autonomous construction of neighbor cell relationships also includes: the terminal adding and / or modifying the initial value of SMTC in the stored valid version of the current serving cell SIB, and modifying the subsequent values ​​of SMTC based on the measurement results. The initial value of SMTC includes the initial value of the measurement window duration and the initial value of the measurement period; when the terminal measures that a neighbor cell exists at a certain frequency point, it reduces the measurement window duration and increases the measurement period based on the measured neighbor cell information.

[0012] This application also proposes another cell measurement assessment and reselection method, including the following steps. Step S21: The terminal accesses and camps on a new cell, receiving SIB1 of that cell; if SIB1 of the cell indicates the existence of an SIB with a system information broadcast status of "broadcasting", the terminal receives the broadcasting SIB and then proceeds to step S22; otherwise, it directly proceeds to step S22. Step S22: The terminal determines whether to receive the remaining SIBs of the cell other than SIB1; if yes, the terminal requests and receives the required SIBs according to the indication of SIB1 of the cell, and then proceeds to step S23; if no, it directly proceeds to step S23. In steps S21 and S22, the terminal also stores the valid version of the received current serving cell SIB and the RRC messages of the current serving cell other than the SIB; and when camping on the current serving cell, it stores the valid version of the previous serving cell SIB in the historically received serving cell SIBs and the RRC messages of the previous serving cell other than the SIB in the historically received RRC messages. Step S23: The terminal requests neighbor cell information from the current serving cell. Step S24: The terminal receives the neighbor cell information returned by the current serving cell. Step S25: The terminal autonomously constructs neighbor cell relationships based on the previously received serving cell SIB, the previously received serving cell SIB after autonomously constructing neighbor cell relationships, the previously received RRC messages, pre-written system information, and the neighbor cell information returned by the current serving cell. This means that the terminal first extracts frequency point information, and then, based on the extracted frequency points, adds previously non-existent inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority fields to the valid version of the current serving cell SIB, or modifies existing inter-frequency measurement frequency points and inter-system measurement frequency points to set reselection priority fields. The purpose of adding or modifying all fields is to enable the terminal to initiate cell reselection in a timely manner or reduce power consumption. After the terminal autonomously constructs neighbor cell relationships, the valid version of the current serving cell SIB becomes the valid version of the SIB after autonomously constructing neighbor cell relationships. When the terminal camps on a serving cell, it stores the valid version of the SIB after autonomously constructing neighbor cell relationships into the previously received serving cell SIB after autonomously constructing neighbor cell relationships. Step S26: The terminal periodically measures the SSB signal strength and quality of the self-constructed neighboring cells. Step S27: The terminal determines if any neighboring cells meet the reselection criteria. If a neighboring cell meets the reselection criteria, it is selected as a reselection candidate cell, and the process proceeds to step S28. If no neighboring cell meets the reselection criteria, and the current serving cell still meets the camping criteria, the process returns to step S26 to continue measurement. If no neighboring cell meets the reselection criteria, and the current serving cell does not meet the camping criteria, but there are one or more NTN neighboring cells that do not meet the reselection criteria and whose remaining service time has not expired, these neighboring cells are considered to meet the reselection criteria, and they are selected as reselection candidate cells, and the process proceeds to step S28.Step S28: The terminal initiates a reselection to the cell with the highest ranking among the reselection candidate cells according to the protocol. If the reselection is successful, return to step S21. If the reselection fails, the terminal remains in the current serving cell and returns to step S26 to continue the measurement.

[0013] Furthermore, in step S23, if the current serving cell is a TN cell and the system information of the TN cell does not indicate NTN neighbor cells, the terminal requests NTN neighbor cell information from the TN cell.

[0014] Furthermore, in step S23, if the current serving cell is a TN cell, when the terminal detects that the signal strength of the current serving cell is lower than the threshold two that characterizes the poor signal quality level of the TN cell, the terminal sends a message to the current serving cell requesting to obtain neighbor cell information.

[0015] This application also proposes a cell measurement, evaluation, and reselection system, including an SIB1 receiving unit, a remaining SIB judgment receiving unit, a neighbor relationship first construction unit, a measurement unit, a reselection condition judgment unit, and a reselection unit. The SIB1 receiving unit is used to receive the SIB1 of a new cell when a terminal accesses and camps on it; if the SIB1 of that cell indicates the existence of an SIB with a system information broadcast status of "broadcasting," the terminal also receives the broadcasting SIB; the SIB1 receiving unit also stores the valid version of the current serving cell SIB received by the terminal, the RRC messages of the current serving cell other than the SIB received by the terminal, and the valid version of the SIB after the current serving cell autonomously constructs neighbor relationships; and when camping on the current serving cell, it stores the valid version of the previous serving cell SIB in the historically received serving cell SIBs, the RRC messages of the previous serving cell other than the SIB in the historically received RRC messages, and the valid version of the SIB after the current serving cell autonomously constructs neighbor relationships in the historically received serving cell SIBs after autonomously constructing neighbor relationships. The remaining SIB determination and receiving unit is used to determine whether the terminal needs to receive the remaining SIBs of the cell other than SIB1. If so, the terminal requests and receives the required SIBs according to the scheduling information in SIB1 of the cell. The first neighbor cell relationship construction unit is used to autonomously construct neighbor cell relationships based on the historically received serving cell SIBs, the historically received serving cell SIBs after autonomously constructing neighbor cell relationships, the historically received RRC messages, and pre-written system information. This means that the terminal first extracts frequency point information, and then adds previously non-existent inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority fields to the effective version of the current serving cell SIB based on the extracted frequency points, or modifies the previously existing inter-frequency measurement frequency points and inter-system measurement frequency points to set reselection priority fields. The purpose of adding or modifying all fields is to enable the terminal to initiate cell reselection in a timely manner or reduce power consumption. After the terminal autonomously constructs the neighbor cell relationships, the effective version of the current serving cell SIB becomes the effective version of the SIB after autonomously constructing neighbor cell relationships. The measurement unit is used to periodically measure the SSB signal strength and quality of the autonomously constructed neighbor cells. The reselection condition judgment unit is used to determine whether there are neighboring cells that meet the reselection conditions. If so, the neighboring cells that meet the reselection conditions are selected as reselection candidate cells. If not, and the current serving cell still meets the camping conditions, the measurement unit continues to perform measurements. If not, and the current serving cell does not meet the camping conditions, but the measurement results show one or more NTN neighboring cells that do not meet the reselection conditions and whose remaining service time has not expired, then these neighboring cells are considered to meet the reselection conditions and are selected as reselection candidate cells. The reselection unit is used to initiate a reselection to the cell with the highest ranking among the reselection candidate cells.

[0016] This application also proposes another cell measurement assessment and reselection system, including an SIB1 receiving unit, other SIB judgment receiving units, a neighbor cell information request unit, a neighbor cell information return unit, a second neighbor cell relationship construction unit, a measurement unit, a reselection condition judgment unit, and a reselection unit. The SIB1 receiving unit is used to receive the SIB1 of a new cell when the terminal accesses and camps on the new cell. If the SIB1 of the cell indicates the existence of an SIB with a system information broadcast status of "broadcasting", the terminal also receives the broadcasting SIB. The SIB1 receiving unit also stores the valid version of the current serving cell SIB received by the terminal, the RRC messages of the current serving cell other than the SIB received by the terminal, and the valid version of the SIB after the current serving cell has autonomously constructed neighbor cell relationships. When camping on the current serving cell, the valid version of the previous serving cell SIB is stored in the historically received serving cell SIBs, the RRC messages of the previous serving cell other than the SIB are stored in the historically received RRC messages, and the valid version of the SIB after the current serving cell has autonomously constructed neighbor cell relationships is stored in the historically received serving cell SIBs after autonomously constructing neighbor cell relationships. The remaining SIB determining receiving unit is used to determine whether the terminal wants to receive the remaining SIBs of the cell other than SIB1. If so, the terminal requests and receives the required SIBs according to the scheduling information indication in the SIB1 of the cell. The neighbor cell information request unit is used to send a message to the current serving cell to request neighbor cell information. The neighbor cell information return unit is used to receive the neighbor cell information returned by the current serving cell. The second neighbor cell relationship construction unit is used to autonomously construct neighbor cell relationships based on the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing neighbor cell relationships, the historically received RRC messages, pre-written system information, and the neighbor cell information returned by the current serving cell. This means that the terminal first extracts frequency point information, and then, based on the extracted frequency points, adds previously non-existent inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority fields to the effective version of the current serving cell SIB, or modifies the previously existing inter-frequency measurement frequency points and inter-system measurement frequency points to set reselection priority fields. The purpose of adding or modifying all fields is to enable the terminal to initiate cell reselection in a timely manner or reduce power consumption. After the terminal autonomously constructs the neighbor cell relationship, the effective version of the current serving cell SIB becomes the effective version of the SIB after the current serving cell autonomously constructs the neighbor cell relationship. The measurement unit is used to periodically measure the SSB signal strength and quality of the autonomously constructed neighbor cells.The reselection condition judgment unit is used to determine whether there are neighboring cells that meet the reselection conditions. If so, the neighboring cells that meet the reselection conditions are selected as reselection candidate cells. If not, and the current serving cell still meets the camping conditions, the measurement unit continues to perform measurements. If not, and the current serving cell does not meet the camping conditions, but the measurement results show one or more NTN neighboring cells that do not meet the reselection conditions and whose remaining service time has not expired, then these neighboring cells are considered to meet the reselection conditions and are selected as reselection candidate cells. The reselection unit is used to initiate a reselection to the cell with the highest ranking among the reselection candidate cells.

[0017] The technical advantages achieved by this application are: by enabling the terminal to autonomously construct neighboring cells, it increases the terminal's opportunities to perform additional cell measurements, reselection condition assessments, and reselections. The terminal can promptly initiate cell reselections across TN and NTN when the current serving cell signal is poor, enhancing terminal mobility and improving the user's network experience. Furthermore, by enabling the terminal to autonomously construct neighboring cells, this application reduces unnecessary measurement overhead and enhances the terminal's energy efficiency. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating an embodiment of the cell measurement, assessment, and reselection method proposed in this application.

[0019] Figures 2A to 2B This is a flowchart illustrating Embodiment 2 of the cell measurement, assessment, and reselection method proposed in this application.

[0020] Figure 3 This is a schematic diagram of an embodiment of the cell measurement, assessment and reselection system proposed in this application.

[0021] Figure 4 This is a schematic diagram of the second embodiment of the cell measurement, assessment and reselection system proposed in this application.

[0022] The following are the reference numerals in the figure: SIB1 receiving unit 11, other SIB judgment receiving unit 12, first neighbor cell relationship construction unit 13, measurement unit 14, reselection condition judgment unit 15, reselection unit 16, neighbor cell information request unit 23, neighbor cell information return unit 24, and second neighbor cell relationship construction unit 25. Detailed Implementation

[0023] Please see Figure 1 The first embodiment of the cell measurement assessment and reselection method proposed in this application includes the following steps.

[0024] Step S11: The terminal successfully accesses a new cell through cell selection or cell reselection and is in a camping state in this cell (hereinafter also referred to as the current serving cell), receiving the SIB1 (System Information Block 1) of this cell. The SIB1 of this cell contains scheduling information of other SIBs in this cell, instructing the terminal on how to receive other SIBs in this cell.

[0025] If the scheduling information in SIB1 of the cell indicates that the system information broadcasting status of a certain SIB of the cell is "broadcasting", then the terminal receives the remaining information of the broadcasting SIB and then proceeds to step S12.

[0026] If the scheduling information in SIB1 of the cell indicates that the system information broadcast status of all SIBs in the cell is "not broadcasting", proceed directly to step S12.

[0027] Step S12: The terminal determines whether to receive the remaining SIBs of the cell other than SIB1. Since the terminal has already received the SIBs of the cell whose system information broadcast status is "broadcasting" in step S1, the object of this step must be the SIBs of the cell whose system information broadcast status is "not broadcasting". In one case, for a necessary SIB—for example, SIB4—if it was not received in step S1, the terminal determines that it needs to receive the necessary SIB. In another case, for SIBs necessary for the terminal to perform a certain function—for example, the terminal needs to receive SIB5 to support LTE, or it needs to receive SIB19 to access via NTN—if it was not received in step S1, the terminal determines that it needs to receive the SIB necessary to perform the certain function.

[0028] If the terminal determines that it needs to receive all SIBs of the cell except SIB1, the terminal requests and receives the required SIBs according to the scheduling information in SIB1 of the cell, and then proceeds to step S13. Specifically, when the cell is a TN cell, the terminal requests and receives system information or neighbor cell relationships related to NTN from the cell's base station; when the cell is an NTN cell, the terminal requests and receives system information or neighbor cell relationships related to TN from the cell's base station. The system information or neighbor cell relationships related to NTN and TN are preferably system information or neighbor cell relationships related to measurement evaluation and cell reselection, such as SIB2, SIB3, SIB4, SIB5, SIB19, SIB25, or neighbor cell relationships contained in these SIBs. SIB2, SIB3, SIB4, SIB5, SIB19, SIB25, etc., may all contain neighbor cell relationships, and different types of neighbor cell relationships will be included depending on the function of each SIB. The neighbor cell relationships carried in these SIBs are updated and obtained by the base station from the core network in real time. As an example, the terminal requests and receives the required SIB from the cell according to the RRC system information request process, and updates its stored neighbor cell information with the neighbor cell relationship carried in the received SIB.

[0029] If the terminal determines that it does not need to receive the other SIBs of the cell except for SIB1, it directly proceeds to step S13.

[0030] In steps S11 and S12, the terminal also stores the valid version of the received current serving cell SIB, and when camped on the current serving cell, stores the valid version of the previous serving cell SIB into the historically received serving cell SIB. Section 5.2.2.2.1, "SIB validity," of 3GPP technical specification 38.331, "NR; Radio Resource Control (RRC); Protocol specification," defines the meaning of the valid SIB version.

[0031] In steps S11 and S12, the terminal also stores the content of the received RRC messages from the current serving cell, excluding the SIB, particularly content related to the current serving cell's measurement configuration, other cell system information, and the current serving cell's dedicated system information. This content helps the terminal autonomously construct neighboring cells. The terminal also stores the content of the previous serving cell's RRC messages (excluding the SIB) into the historically received RRC messages while camped on the current serving cell.

[0032] Step S13: The terminal autonomously constructs neighbor cell relationships based on the historically received serving cell SIBs, the historically received serving cell SIBs after autonomously constructing neighbor cell relationships, the historically received RRC messages, and pre-written system information. If any item is missing, such as "the historically received serving cell SIBs after autonomously constructing neighbor cell relationships," then that item is omitted.

[0033] The pre-written system information refers to neighbor cell relationships that are not communicated to the terminal by the network side, but are pre-saved by the terminal. For example, if the terminal manufacturer knows that a cell exists at a certain location and frequency, it can pre-write inter-frequency neighbor cell information in SIB4 without needing to be notified by the network side.

[0034] Specifically, the terminal extracts the frequency point information defined as "frequency point" from the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing neighbor cell relationships, the historically received RRC messages, and the pre-written system information, and then autonomously constructs the neighbor cell relationships.

[0035] The first step, extracting frequency information, is equivalent to obtaining neighbor cell relationships. This includes, for example, the frequency points indicated by the SIB4 neighbor list of a cell in a historically received serving cell SIB; the frequency points indicated by the SIB4 neighbor list of a cell in a historically received serving cell SIB after the self-constructed neighbor cell relationships; the frequency points indicated by the measurement object of an RRC Reconfiguration message or the redirection frequency of an RRC Release message in a historically received RRC message, or the SIB1 message matched by the PLMN (Public Ground Mobile Network); the frequency points indicated by the dedicated SIB19 information of the RRC Reconfiguration message in a historically received RRC message; and the frequency points indicated by pre-written system information. Preferably, after the terminal extracts the neighbor cell relationship (i.e., frequency information) from a historically received serving cell SIB, it clears that serving cell SIB from the historically received serving cell SIB to free up more storage space. Preferably, after the terminal extracts the neighbor cell relationship (i.e., frequency information) from a previously received serving cell SIB with a self-constructed neighbor cell relationship, it removes that serving cell SIB from the previously received serving cell SIBs with self-constructed neighbor cell relationships to free up more storage space. Preferably, after the terminal extracts the neighbor cell relationship (i.e., frequency information) from a previously received RRC message, it removes that RRC message from the previously received RRC messages to free up more storage space.

[0036] The second step, autonomously constructing neighbor cell relationships, refers to the terminal adding and / or modifying content in the stored valid version of the current serving cell SIB. Based on the extracted frequency information, it adds fields such as previously non-existent inter-frequency measurement frequencies, inter-system measurement frequencies, and cell reselection priority, or modifies existing inter-frequency and inter-system measurement frequencies to set reselection priority fields. The purpose of adding or modifying all fields is to enable the terminal to initiate cell reselection promptly or reduce power consumption. The neighbor cell relationships autonomously constructed by the terminal can serve as criteria for subsequent measurement evaluation and cell reselection. After the terminal autonomously constructs the neighbor cell relationships, the valid version of the current serving cell SIB becomes "the valid version of the SIB after autonomously constructing neighbor cell relationships for the current serving cell," and the two are interconnected, stored together, and released together. When the terminal camps on a serving cell, it stores "the valid version of the SIB after autonomously constructing neighbor cell relationships for the current serving cell" into the historically received serving cell SIB after autonomously constructing neighbor cell relationships.

[0037] In this step, the terminal sets the frequency reselection priority for the frequency points in the autonomously constructed neighbor cell relationship based on information such as the current serving cell signal quality, the current cell location (TN cell center area, TN cell edge area, NTN cell center area, NTN cell edge area), and the current cell type (TN cell, NTN cell, etc.). The setting strategy takes into account both mobility and energy saving, and specifically includes the following four aspects.

[0038] Firstly, if the terminal's current serving cell is a TN cell, and the newly added or modified inter-frequency measurement points and inter-system measurement points include NTN frequency points, if the signal strength of the TN cell is higher than a threshold (e.g., -90dB) that characterizes the signal quality level of the TN cell, then the reselection priority of the NTN frequency point is set to low priority, that is, lower than the reselection priority of the frequency point of the current serving cell, so as to reduce or eliminate NTN measurements, thereby reducing power consumption and enhancing energy saving.

[0039] Secondly, if the terminal's current camping cell is a TN cell, and the newly added or modified inter-frequency measurement points and inter-system measurement points include NTN frequency points, and if the signal strength of the TN cell is lower than the threshold two (e.g., -120dB) that characterizes the poor signal quality level of the TN cell, and the terminal is in the edge area of ​​the TN cell, then the reselection priority of the NTN frequency point is set to high priority, that is, higher than the reselection priority of the frequency point of the current serving cell, so that the NTN frequency point meets the measurement initiation criteria of the protocol constraint and the NTN frequency point measurement is started immediately to enhance mobility.

[0040] Thirdly, the terminal's current camped cell is a TN cell, and the newly added or modified inter-frequency measurement points and inter-system measurement points include NTN frequencies. The terminal has already obtained the SIB19 or dedicated SIB19 of the NTN neighboring cell—for example, by obtaining the dedicated SIB19 of the NTN neighboring cell through conditional handover configuration. In the first case, the SIB19 or dedicated SIB19 of the NTN neighboring cell contains location parameters. If the terminal does not meet either the time or location restrictions of the NTN neighboring cell—that is, the time does not meet the t-Service definition in the protocol or the location does not meet the referenceLocation definition in the protocol—the reselection priority of that NTN neighboring cell is set to low priority, achieving the goal of reducing or eliminating NTN measurements and enhancing energy efficiency. If the terminal simultaneously meets the time and location restrictions of the NTN neighboring cell—that is, the time meets the t-Service definition in the protocol and the location meets the referenceLocation definition in the protocol—the reselection priority of that NTN neighboring cell is set to high priority, and NTN measurements are immediately initiated to enhance mobility. In the second case, the SIB19 or dedicated SIB19 of the NTN neighboring cell does not contain location parameters. When a terminal does not meet the time limit of an NTN neighbor cell—that is, the time does not meet the t-Service definition in the protocol—the reselection priority of that NTN neighbor cell is set to low priority, thereby reducing or eliminating NTN measurements and enhancing energy efficiency. When a terminal meets the time limit of an NTN neighbor cell—that is, the time meets the t-Service definition in the protocol—the reselection priority of that NTN neighbor cell is set to high priority, and NTN measurements are immediately initiated to enhance mobility.

[0041] Fourthly, if the terminal's current camping cell is an NTN cell, and the newly added or modified inter-frequency measurement points and inter-system measurement points include TN frequency points, and if the uplink or downlink rate of the NTN cell is low, then the reselection priority of the TN frequency point is set to high priority, that is, higher than the reselection priority of the frequency point of the current serving cell, so that the TN frequency point meets the measurement initiation criteria of the protocol constraints and the TN frequency point measurement is started immediately to enhance mobility.

[0042] In this context, the central area of ​​a TN cell refers to the central area covered by the terrestrial network, while the edge area of ​​a TN cell refers to the junction between the terrestrial network and non-terrestrial networks or other networks. Similarly, the central area of ​​an NTN cell refers to the central area covered by a non-terrestrial network, and the edge area of ​​an NTN cell refers to the junction between the non-terrestrial network and the terrestrial network or other networks. For example, a terminal obtains the coverage area of ​​its current serving cell through the network or pre-configured information, and further determines whether it is in the edge area of ​​a TN cell based on its current location. Another example: if the terminal's current serving cell is a TN cell, and the RSRP (Reference Signal Received Power) of that TN cell is lower than a threshold two (e.g., -120dB) indicating poor signal quality, and there are no TN neighboring cells measured within time T1 (e.g., 10 seconds), then the terminal is considered to be in the edge area of ​​a TN cell. Yet another example: if the terminal's current serving cell is a TN cell, and the decrease in the RSRP of that TN cell is greater than a threshold three (e.g., 30dB) indicating a drastic decrease in signal quality, and there are no TN neighboring cells measured within time T2 (e.g., 10 seconds), then the terminal is considered to be in the edge area of ​​a TN cell. For example, if the terminal's current camping cell is an NTN cell, and the remaining service time of the NTN cell is less than a threshold four (e.g., 15 seconds) that indicates a short remaining service time for the NTN cell, and the measurement results within time T3 (e.g., 10 seconds) show TN neighboring cells, then the terminal is considered to be currently in the edge region of the NTN cell.

[0043] Optionally, the autonomous construction of neighbor cell relationships further includes: the terminal adding and / or modifying the initial value of SMTC (SSB measurement timing configuration) in the stored valid version of the current serving cell's SIB, and modifying the subsequent values ​​of SMTC based on the measurement results. For example, the initial value of the measurement window duration is set to sf5, and the initial value of the measurement period is also set to sf5, meaning that a measurement window duration of 5ms is performed every 5ms to enable the terminal to quickly measure neighbor cells. When the terminal measures that a neighbor cell exists at a certain frequency point, it reduces the measurement window duration and increases the measurement period based on the measured neighbor cell information to improve measurement efficiency and achieve power saving. If the measured neighbor cell is an NTN cell, the measurement period is increased to no more than the value of the default SSB broadcast period for that NTN frequency point as specified in the protocol to enhance energy saving. If an NTN cell exists in the current serving cell or the measured neighbor cell, the measurement window duration is adjusted according to the actual propagation delay difference between the current serving cell and the measured neighbor cell to avoid the inability to measure the neighbor cell due to the SSB position of the measured neighbor cell not being strictly synchronized with the current serving cell.

[0044] In this step, if the following condition is met according to the protocol: "The current serving cell indicates that a valid version of a historically received serving cell SIB can be applied to the current serving cell", then the terminal will no longer autonomously construct neighbor cell relationships for the current serving cell. Instead, the terminal will find the valid version of the historically received serving cell SIB after autonomously constructing neighbor cell relationships in "historically received serving cell SIBs after autonomously constructing neighbor cell relationships" and use it as the valid version of the current serving cell's SIB after autonomously constructing neighbor cell relationships.

[0045] Optionally, the terminal sets an expiration period (e.g., 3 hours) for the data in the historically received serving cell SIB, the historically received serving cell SIB after the self-constructed neighbor cell relationship, and the historically received RRC messages. When a piece of data exceeds the expiration period since the last reception, it is cleared as invalid data.

[0046] Step S14: The terminal periodically measures the SSB signal strength and quality according to the protocol and the content indicated by "the effective version of the SIB after the current serving cell autonomously constructs the neighbor cell relationship" (i.e., the autonomously constructed neighbor cell relationship).

[0047] Step S15: The terminal evaluates whether the measured neighboring cells are more suitable for camping than the current serving cell according to the protocol, that is, it determines whether there are neighboring cells that meet the reselection conditions.

[0048] If there are one or more neighboring cells that are more suitable for re-selection (i.e., there are neighboring cells that meet the re-selection criteria), then the neighboring cells that meet the re-selection criteria will be used as re-selection candidate cells, and the process will proceed to step S16.

[0049] If there is no more suitable neighboring cell for relocation, and the current serving cell still meets the relocation conditions according to the agreement, then return to step S14 to continue the measurement.

[0050] If there are no more suitable neighboring cells for re-selection, and the current serving cell does not meet the re-selection conditions according to the agreement, but the measurement results show one or more NTN neighboring cells that do not meet the re-selection conditions and whose remaining service time has not expired, then these neighboring cells are considered to meet the re-selection conditions, and these neighboring cells are used as re-selection candidate cells, and the process proceeds to step S16.

[0051] If none of the above conditions are met, the terminal enters a network loss state and reselects a cell according to the protocol.

[0052] Step S16: The terminal initiates a reselection process with the highest-ranked cell among the candidate cells, according to the protocol. The order of the candidate cells is determined according to technical specification TS38.304.

[0053] If the reselection is successful, return to step S11.

[0054] If the reselection fails, the terminal will remain in the current serving cell and return to step S14 to continue the measurement.

[0055] The above embodiment 1 adds additional inter-frequency or inter-system measurement frequency points to the SIB of the current serving cell and sets reselection priority for the newly added frequency points, which is called autonomously constructing the neighbor cell relationship of the current serving cell. This increases the probability of reselecting from a TN cell to an NTN cell or from an NTN cell to a TN cell when the signal quality of the current serving cell is poor, thereby enhancing the mobility of the terminal; or reduces inter-frequency or inter-system measurements when the signal quality of the current serving cell is good, thereby reducing power consumption.

[0056] Please see Figures 2A to 2B The second embodiment of the cell measurement assessment and reselection method proposed in this application includes the following steps.

[0057] Steps S21 to S22 are equivalent to steps S11 to S12, respectively.

[0058] Step S23: The terminal sends a message to its current serving cell, requesting neighbor cell information. For example, the request message includes fields such as the requested neighbor cell type, requested system information, the terminal's current location, and the terminal's current PLMN list, instructing the network side to send neighbor cell information. Another example is if the terminal's current serving cell is a TN cell, and the TN cell's system information does not indicate NTN neighbor cells; the terminal requests NTN neighbor cell information from this TN cell to enhance mobility. Yet another example is when the terminal subscribes to roaming services, it fills in the equivalent PLMN field in the request message to obtain neighbor cell information from a different operator to enhance mobility.

[0059] Preferably, if the current serving cell is a TN cell, when the terminal detects that the signal strength of the current serving cell is lower than a threshold two (e.g., -120dB) that characterizes the poor signal quality level of the TN cell, or when the terminal needs to obtain neighbor cell information to optimize network connectivity, the terminal sends a message to the current serving cell requesting to obtain neighbor cell information.

[0060] Preferably, the request message is encapsulated as a new RRC uplink signaling message or incorporated into an extended field of an existing RRC uplink signaling message. The existing RRC uplink signaling messages include: RRC Setup Request messages, RRC System Info Request messages, UE Assistance Information messages, RRC Resume Request messages, and RRC Reestablishment Request messages, etc. These messages require an explicit response from the network side.

[0061] Currently, the broadcast reception method, RRC system information acquisition method, and dedicated SIB request method for acquiring system information all require explicit indication of the system information's scheduling information; that is, the SIB1 message must include the si-SchedulingInfo field after decoding, thus only allowing the acquisition of complete system information. The method proposed in this application, where the terminal requests neighbor cell information from the network side, does not require indicating the system information's scheduling information in the SIB1 message, allowing the acquisition of partial system information. For example, when a terminal requests NTN neighbor cell information on a TN cell, it can acquire only the NTN neighbor cell configuration from SIB19, without needing to acquire fields such as t-Service related to NTN cell access. This is a supplement to the system information reception method specified in the protocol, aiming to provide a more flexible way to acquire neighbor cell information within the system information.

[0062] Step S24: The terminal receives neighbor cell information returned by the current serving cell. This neighbor cell information is obtained, for example, by the base station of the current serving cell querying the core network or the unit in the mobile communication network responsible for managing neighbor cell information.

[0063] In this step, the terminal may also receive paging messages from the current serving cell indicating system updates, rejecting terminal requests, indicating radio link failures, or stopping the terminal request process. Preferably, all types of return messages are encapsulated separately into new RRC downlink signaling or aggregated within existing RRC downlink signaling. The existing RRC downlink signaling includes: RRC setup messages, RRC reconfiguration messages, etc. Return messages containing neighbor cell information can also be reflected through the paging system message update process. Messages rejecting terminal requests can also be implemented by adding fields to the random access response message.

[0064] Step S25: The terminal autonomously constructs neighbor cell relationships based on the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing neighbor cell relationships, the historically received RRC messages, pre-written system information, and the neighbor cell information returned by the current serving cell. If any item is missing, such as "the historically received serving cell SIB after autonomously constructing neighbor cell relationships," that item is omitted. Specifically, the terminal first extracts the frequency point information from the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing neighbor cell relationships, the historically received RRC messages, the pre-written system information, and the neighbor cell information returned by the current serving cell, and then autonomously constructs the neighbor cell relationships. After the terminal autonomously constructs the neighbor cell relationships, the effective version of the current serving cell SIB becomes the effective version of the SIB after autonomously constructing neighbor cell relationships for the current serving cell. When the terminal camps on a serving cell, it stores the effective version of the SIB after autonomously constructing neighbor cell relationships for the current serving cell into the historically received serving cell SIB after autonomously constructing neighbor cell relationships.

[0065] Steps S26 to S28 are equivalent to steps S14 to S16, respectively.

[0066] The difference between Embodiment 2 and Embodiment 1 lies only in that the terminal additionally obtains the neighbor cell information of the current serving cell through the newly added steps S23 and S24, and constructs the neighbor cell relationship based on the four pieces of information disclosed in Embodiment 1 (historically received serving cell SIB, historically received serving cell SIB after autonomously constructing neighbor cell relationships, historically received RRC messages, and pre-written system information) and the one piece of information added in Embodiment 2 (the neighbor cell information of the current serving cell). In both embodiments, the terminal autonomously constructs the neighbor cell relationship of the current serving cell based on the obtained neighbor cell information, thereby enhancing the terminal's mobility or reducing power consumption.

[0067] Please see Figure 3 The first embodiment of the cell measurement assessment and reselection system proposed in this application includes an SIB1 receiving unit 11, a remaining SIB judgment receiving unit 12, a neighbor cell relationship first construction unit 13, a measurement unit 14, a reselection condition judgment unit 15, and a reselection unit 16. Figure 3 The first embodiment of the system shown corresponds to Figure 1 Example 1 of the method shown.

[0068] The SIB1 receiving unit 11 is used to receive the SIB1 of a new cell when the terminal successfully accesses and camps on the cell. If the scheduling information in the SIB1 of the cell indicates that the system information broadcast status of a certain SIB of the cell is "broadcasting", the terminal also receives the remaining information of the SIB that is being broadcast.

[0069] During the period when the SIB1 receiving unit 11 receives the SIB1 of the current serving cell and the SIBs being broadcast, the SIB1 receiving unit 11 also stores the valid version of the current serving cell SIB received by the terminal, and stores the content of the RRC messages of the current serving cell other than the SIBs received by the terminal. During the period when the remaining SIB determination receiving unit 12 receives the other required SIBs of the current serving cell other than SIB1, the SIB1 receiving unit 11 also stores the valid version of the current serving cell SIB received by the terminal, and stores the content of the RRC messages of the current serving cell other than the SIBs received by the terminal. After the neighbor cell relationship first construction unit 13 (or neighbor cell relationship second construction unit 25) autonomously constructs the neighbor cell relationship, the SIB1 receiving unit 11 also stores the valid version of the SIB after the current serving cell autonomously constructs the neighbor cell relationship.

[0070] When the SIB1 receiving unit 11 is still camped on the current serving cell, it stores the valid version of the previous serving cell's SIB into the historically received serving cell SIB, stores the content of the previous serving cell's RRC messages other than the SIB into the historically received RRC messages, and stores the valid version of the current serving cell's SIB after autonomously constructing neighbor cell relationships into the historically received serving cell SIB after autonomously constructing neighbor cell relationships.

[0071] The remaining SIB determination receiving unit 12 is used to determine whether the terminal wants to receive the remaining SIBs of the cell other than SIB1. If so, the terminal requests and receives the required SIBs according to the scheduling information indication in SIB1 of the cell.

[0072] The first neighbor cell relationship construction unit 13 is used to autonomously construct neighbor cell relationships based on historically received serving cell SIBs, historically received serving cell SIBs after autonomously constructing neighbor cell relationships, historically received RRC messages, and pre-written system information. Specifically, it first extracts frequency point information, that is, obtains neighbor cell relationships; then, it adds and / or modifies content in the stored valid version of the current serving cell SIB. Based on the extracted frequency point information, it adds fields such as inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority that did not exist before, or modifies fields such as inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority that already exist. The purpose of adding or modifying all fields is to enable the terminal to initiate cell reselection in a timely manner or reduce power consumption. After autonomously constructing neighbor cell relationships, the valid version of the current serving cell SIB becomes the valid version of the SIB after the current serving cell autonomously constructs neighbor cell relationships.

[0073] The measurement unit 14 is used to periodically measure the SSB signal strength and quality of the autonomously constructed neighboring cells.

[0074] The reselection condition judgment unit 15 is used to determine whether there are neighboring cells that meet the reselection conditions. If so, the neighboring cells that meet the reselection conditions are used as reselection candidate cells. If not, and the current serving cell still meets the camping conditions, the measurement unit 14 continues to perform measurements. If not, and the current serving cell does not meet the camping conditions, but the measurement results show one or more NTN neighboring cells that do not meet the reselection conditions and whose remaining service time has not expired, then these neighboring cells are considered to meet the reselection conditions and are used as reselection candidate cells. If none of the above conditions are met, the terminal enters a network loss state.

[0075] The reselection unit 16 is used to initiate a reselection to the cell with the highest ranking among the reselection candidate cells.

[0076] Please see Figure 4 The second embodiment of the cell measurement assessment and reselection system proposed in this application includes an SIB1 receiving unit 11, a remaining SIB judgment receiving unit 12, a neighbor cell information request unit 23, a neighbor cell information return unit 24, a second neighbor cell relationship construction unit 25, a measurement unit 14, a reselection condition judgment unit 15, and a reselection unit 16. Figure 3 and Figure 4 In both embodiments, the same unit performs the same function. Figure 4 The second embodiment of the system shown corresponds to the second embodiment of the method shown in Figure 2.

[0077] The neighbor cell information request unit 23 is used to send a message to the current serving cell to request neighbor cell information.

[0078] The neighbor cell information return unit 24 is used to receive neighbor cell information returned by the currently serving cell.

[0079] The second neighbor cell relationship construction unit 25 is used to autonomously construct neighbor cell relationships based on historically received serving cell SIBs, historically received serving cell SIBs after autonomously constructing neighbor cell relationships, historically received RRC messages, pre-written system information, and neighbor cell information returned by the current serving cell. Specifically, frequency point information is first extracted. Then, based on the extracted frequency point information, fields such as inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority that were not previously present are added to the stored valid version of the current serving cell SIB, or existing fields such as inter-frequency measurement frequency points, inter-system measurement frequency points, and reselection priority are modified. The purpose of adding or modifying all fields is to enable the terminal to initiate cell reselection in a timely manner or reduce power consumption. After autonomously constructing neighbor cell relationships, the valid version of the current serving cell SIB becomes the valid version of the SIB after the current serving cell autonomously constructs neighbor cell relationships.

[0080] This application enables the terminal to autonomously construct neighboring cells, allowing it to perform additional cell measurements, cell reselection condition assessments, and cell reselection procedures based on these cells. This allows the terminal to promptly initiate cell reselection between TN and NTN when the current serving cell signal is weak, enhancing terminal mobility and improving the user's network experience. Conversely, when the current serving cell signal is good, the terminal reduces inter-frequency or inter-system measurements to lower power consumption.

[0081] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method of cell measurement evaluation and reselection, c h a r a c t e r i s e d i n that Comprising the following steps: Step S11: the terminal accesses and camps on a new cell, and receives SIB1 of the cell; if SIB1 of the cell indicates that there is a SIB with a system information broadcast state of "being broadcast", the terminal receives the SIB being broadcast, and then enters step S12; otherwise, it directly enters step S12; Step S12: the terminal determines whether it needs to receive the remaining SIBs of the cell other than SIB1; If yes, the terminal requests and receives the required SIBs according to the indication of SIB1 of the cell, and then enters step S13; if no, it directly enters step S13; In the steps S11 and S12, the terminal also stores the valid version of the received SIB of the current serving cell and the RRC message of the current serving cell other than SIB; and when camping on the current serving cell, it stores the valid version of the SIB of the previous serving cell into the historically received SIB of the serving cell, and stores the RRC message of the previous serving cell other than SIB into the historically received RRC message; Step S13: the terminal autonomously constructs the neighbor relation according to the historically received SIB of the serving cell, the historically received SIB of the serving cell after autonomously constructing the neighbor relation, the historically received RRC message and the pre-written system information; this means that the terminal first extracts the frequency point information, and then, according to the extracted frequency point, adds the previously non-existing inter-frequency measurement frequency point, inter-system measurement frequency point and reselection priority field in the valid version of the SIB of the current serving cell, or modifies the previously existing inter-frequency measurement frequency point and inter-system measurement frequency point to set the reselection priority field for them, so that the terminal can timely initiate cell reselection or reduce power consumption; after the terminal autonomously constructs the neighbor relation, the valid version of the SIB of the current serving cell becomes the valid version of the SIB of the current serving cell after autonomously constructing the neighbor relation; the terminal stores the valid version of the SIB of the current serving cell after autonomously constructing the neighbor relation into the historically received SIB of the serving cell after autonomously constructing the neighbor relation when camping on the next serving cell; Step S14: the terminal periodically measures the SSB signal strength and quality of the autonomously constructed neighbor; Step S15: the terminal determines whether there is a neighbor meeting the reselection condition; If there is a neighbor meeting the reselection condition, the neighbor meeting the reselection condition is taken as a reselection candidate cell, and the process goes to step S16; If there is no neighbor meeting the reselection condition, and the current serving cell still meets the camping condition, the process goes back to step S14 for measurement; If there is no neighbor meeting the reselection condition, and the current serving cell does not meet the camping condition, but there is one or more NTN neighbors that do not meet the reselection condition and whose remaining service time has not expired, these neighbors are considered to meet the reselection condition, and these neighbors are taken as reselection candidate cells, and the process goes to step S16; Step S16: the terminal initiates reselection to the cell ranked highest in the reselection candidate cells according to the protocol; if the reselection is successful, the process goes back to step S11; if the reselection fails, the terminal still camps on the current serving cell, and the process goes back to step S14 for measurement. ​ 2. The cell measurement evaluation and reselection method according to claim 1, characterized in that, In the step S12, when the cell is a TN cell, the terminal requests and receives system information related to measurement evaluation and cell reselection of the NTN cell from the base station of the cell, including SIB2, SIB3, SIB4, SIB5, SIB19, SIB25 or the neighboring cell relation contained in these SIBs. In the step S12, when the cell is a TN cell, the terminal requests and receives system information related to measurement evaluation and cell reselection of the NTN cell from the base station of the cell, including SIB2, SIB3, SIB4, SIB5, SIB19, SIB25 or the neighboring cell relation contained in these SIBs.

3. The cell measurement evaluation and reselection method according to claim 1, characterized in that, In the step S13, the terminal extracts the frequency point information including any one or more of the following: a frequency point indicated by the SIB4 neighboring cell list of a certain cell in the SIB of the historically received serving cell, a frequency point indicated by the SIB4 neighboring cell list after the autonomous construction of the neighboring cell relation of a certain cell in the SIB of the serving cell after the autonomous construction of the neighboring cell relation, a frequency point indicated by the SIB1 message of the PLMN matching or the redirection frequency point of the RRC release message or the measurement object of the RRC reconfiguration message in the RRC message historically received, a frequency point indicated by the dedicated SIB19 information of the RRC reconfiguration message in the RRC message historically received, a frequency point indicated in the pre-written system information.

4. The cell measurement evaluation and reselection method according to claim 1, characterized in that, In the step S13, the terminal sets the reselection priority for the newly added or modified inter-frequency measurement frequency point or inter-system measurement frequency point, including the following contents: In the first aspect, the current camped cell of the terminal is a TN cell, the newly added or modified inter-frequency measurement frequency point or inter-system measurement frequency point includes an NTN frequency point, and if the signal strength of the TN cell is higher than a threshold one representing a better signal quality level of the TN cell, the reselection priority of the NTN frequency point is set to a low priority. In the second aspect, the current camped cell of the terminal is a TN cell, the newly added or modified inter-frequency measurement frequency point or inter-system measurement frequency point includes an NTN frequency point, and if the signal strength of the TN cell is lower than a threshold two representing a poor signal quality level of the TN cell and the terminal is in a TN cell edge area, the reselection priority of the NTN frequency point is set to a high priority. In the third aspect, the current camped cell of the terminal is a TN cell, the newly added or modified inter-frequency measurement frequency point or inter-system measurement frequency point includes an NTN frequency point, and the terminal has acquired the SIB19 or dedicated SIB19 of the NTN neighboring cell. In the first case, the SIB19 or dedicated SIB19 of the NTN neighboring cell contains a location parameter, and when the terminal does not satisfy any one of the time or location restrictions of the NTN neighboring cell, the reselection priority of the NTN neighboring cell is set to a low priority, and when the terminal satisfies both the time and location restrictions of the NTN neighboring cell, the reselection priority of the NTN neighboring cell is set to a high priority. In the second case, the location parameter is not present in the SIB19 or the dedicated SIB19 of the NTN neighbor cell; when the terminal does not meet the time limit of the NTN neighbor cell, the reselection priority of the NTN neighbor cell is set to a low priority; when the terminal meets the time limit of the NTN neighbor cell, the reselection priority of the NTN neighbor cell is set to a high priority. In the fourth aspect, the current camped cell of the terminal is an NTN cell, and the newly added or modified inter-frequency measurement frequency point and inter-system measurement frequency point include a TN frequency point; if the uplink rate or the downlink rate of the NTN cell is low, the reselection priority of the TN frequency point is set to a high priority.

5. The cell measurement evaluation and reselection method of claim 1, wherein, In the step S13, the terminal autonomously constructing the neighbor cell relationship further includes: the terminal adding and / or modifying the initial value of the SMTC in the stored valid version of the SIB of the current serving cell, and modifying the subsequent value of the SMTC based on the measurement result; The initial value of the SMTC includes the initial value of the measurement window duration and the initial value of the measurement period; after the terminal measures that there is a neighbor cell in a certain frequency point, the measurement window duration is reduced and the measurement period is increased according to the measured neighbor cell information.

6. A method of cell measurement evaluation and reselection, c h a r a c t e r i s e d i n t h a t The method comprises the following steps: Step S21: the terminal accesses and camps on a new cell, and receives the SIB1 of the cell; if the SIB1 of the cell indicates that there is a SIB with a system information broadcast state of "broadcasting", the terminal receives the SIB being broadcast, and then enters step S22; otherwise, it directly enters step S22; Step S22: the terminal determines whether to receive the remaining SIBs other than the SIB1 of the cell; If yes, the terminal requests and receives the required SIB according to the indication of the SIB1 of the cell, and then enters step S23; if no, it directly enters step S23; In the steps S21 and S22, the terminal further stores the received valid version of the SIB of the current serving cell and the RRC message other than the SIB of the current serving cell; and when camping on the current serving cell, stores the valid version of the SIB of the previous serving cell into the historically received SIB of the serving cell, and stores the RRC message other than the SIB of the previous serving cell into the historically received RRC message; Step S23: the terminal requests the current serving cell to obtain the neighbor cell information; Step S24: the terminal receives the neighbor cell information returned by the current serving cell; ​ Step S25: The terminal autonomously constructs the neighbor relation according to the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing the neighbor relation, the historically received RRC message, the pre-written system information, and the neighbor information returned by the current serving cell. This means that the terminal first extracts the frequency point information, and then, in the valid version of the current serving cell SIB, adds the inter-frequency measurement frequency point, the inter-system measurement frequency point, and the reselection priority field that did not originally exist, or modifies the inter-frequency measurement frequency point and the inter-system measurement frequency point to set the reselection priority field for them, so that the terminal can timely initiate cell reselection or reduce power consumption. After the terminal autonomously constructs the neighbor relation, the valid version of the current serving cell SIB becomes the valid version of the SIB of the current serving cell after autonomously constructing the neighbor relation. When the terminal camps on the next serving cell, the valid version of the SIB of the current serving cell after autonomously constructing the neighbor relation is stored in the historically received serving cell SIB after autonomously constructing the neighbor relation; Step S26: The terminal periodically measures the SSB signal strength and quality of the autonomously constructed neighbor; Step S27: The terminal determines whether there is a neighbor that meets the reselection condition; If there is a neighbor that meets the reselection condition, the neighbor that meets the reselection condition is taken as a reselection candidate cell, and the process proceeds to step S28; If there is no neighbor that meets the reselection condition, and the current serving cell still meets the camping condition, the process returns to step S26 for continued measurement; If there is no neighbor that meets the reselection condition, and the current serving cell does not meet the camping condition, but there is one or more NTN neighbors that do not meet the reselection condition and whose remaining service time has not expired, these neighbors are considered to meet the reselection condition, and these neighbors are taken as reselection candidate cells, and the process proceeds to step S28; Step S28: The terminal initiates reselection to the cell ranked highest in the reselection candidate cells according to the protocol. If the reselection is successful, the process returns to step S21. If the reselection fails, the terminal still camps on the current serving cell, and the process returns to step S26 for continued measurement.

7. The cell measurement evaluation and reselection method of claim 6, characterized in that, In step S23, if the current serving cell is a TN cell, the terminal requests the NTN neighbor information from the TN cell.

8. The cell measurement evaluation and reselection method of claim 6, wherein, In step S23, if the current serving cell is a TN cell, when the terminal detects that the current serving cell signal strength is lower than the threshold two representing a poor signal quality level of the TN cell, the terminal sends a message to the current serving cell to request neighbor information.

9. A cell measurement evaluation and reselection system, characterized by, The terminal includes an SIB1 receiving unit, a remaining SIB determining and receiving unit, a neighbor relation first constructing unit, a measuring unit, a reselection condition determining unit, and a reselection unit. The SIB1 receiving unit is configured to receive SIB1 of a new cell when a terminal accesses and camps on the new cell; if the SIB1 of the new cell indicates that there is a SIB with a system information broadcast state of "being broadcast", the terminal further receives the SIB being broadcast; the SIB1 receiving unit further stores a valid version of a SIB of a current serving cell received by the terminal, a RRC message other than the SIB of the current serving cell received by the terminal, and a valid version of a SIB after the current serving cell autonomously constructs a neighbor relation; and when camping on the current serving cell, stores the valid version of the SIB of the previous serving cell into a historically received serving cell SIB, stores the RRC message other than the SIB of the previous serving cell into a historically received RRC message, and stores the valid version of the SIB after the current serving cell autonomously constructs a neighbor relation into a historically received serving cell SIB after autonomously constructing a neighbor relation; The remaining SIB judging receiving unit is configured to judge whether the terminal needs to receive remaining SIBs other than the SIB1 of the cell; If yes, the terminal receives the required SIB according to the indication request in the scheduling information in the SIB1 of the cell; The neighbor relation first constructing unit is configured to autonomously construct a neighbor relation according to the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing a neighbor relation, the historically received RRC message, and pre-written system information; this means that the terminal first extracts frequency point information, and then adds a field of inter-frequency measurement frequency point, inter-system measurement frequency point, and reselection priority which did not originally exist in the valid version of the current serving cell SIB, or modifies the inter-frequency measurement frequency point and the inter-system measurement frequency point to set the field of reselection priority, so that the terminal initiates cell reselection in time or reduces power consumption; after the terminal autonomously constructs a neighbor relation, the valid version of the current serving cell SIB becomes the valid version of the SIB of the current serving cell after autonomously constructing a neighbor relation; The measuring unit is configured to periodically measure SSB signal strength and quality of the autonomously constructed neighbor; The reselection condition judging unit is configured to judge whether there is a neighbor meeting a reselection condition; If yes, the neighbor meeting the reselection condition is taken as a reselection candidate cell; if no, and the current serving cell still meets the camping condition, the measuring unit continues to perform measurement; if no, and the current serving cell does not meet the camping condition, but there is one or more NTN neighbors which do not meet the reselection condition and whose remaining service time has not expired, these neighbors are considered to meet the reselection condition, and these neighbors are taken as reselection candidate cells; The reselection unit is configured to initiate reselection to the cell with the highest ranking in the reselection candidate cells.

10. A cell measurement evaluation and reselection system, characterized by, The SIB1 receiving unit, the remaining SIB judging receiving unit, the neighbor information requesting unit, the neighbor information returning unit, the neighbor relation second constructing unit, the measuring unit, the reselection condition judging unit, and the reselection unit are included. The SIB1 receiving unit is configured to receive SIB1 of a new cell when the terminal accesses and camps on the new cell; if the SIB1 of the new cell indicates that there is a SIB with a system information broadcast state of "broadcasting", the terminal further receives the SIB being broadcast; the SIB1 receiving unit further stores the valid version of the SIB of the current serving cell received by the terminal, the RRC message other than the SIB of the current serving cell received by the terminal, and the valid version of the SIB after the current serving cell autonomously constructs a neighbor relation; and when camping on the current serving cell, stores the valid version of the SIB of the previous serving cell into the historically received serving cell SIB, stores the RRC message other than the SIB of the previous serving cell into the historically received RRC message, and stores the valid version of the SIB after the current serving cell autonomously constructs a neighbor relation into the historically received serving cell SIB after autonomously constructing a neighbor relation; The remaining SIB judging receiving unit is configured to judge whether the terminal needs to receive the remaining SIBs other than the SIB1 of the cell; If yes, the terminal receives the required SIB according to the indication request in the scheduling information in the SIB1 of the cell; The neighbor information requesting unit is configured to send a message to the current serving cell to request to obtain neighbor information; The neighbor information returning unit is configured to receive the neighbor information returned by the current serving cell; The neighbor relation second constructing unit is configured to autonomously construct a neighbor relation according to the historically received serving cell SIB, the historically received serving cell SIB after autonomously constructing a neighbor relation, the historically received RRC message, the pre-written system information, and the neighbor information returned by the current serving cell; this means that the terminal first extracts frequency point information, and then adds a field of inter-frequency measurement frequency point, inter-system measurement frequency point, and reselection priority which did not originally exist in the valid version of the current serving cell SIB, or modifies the inter-frequency measurement frequency point and the inter-system measurement frequency point to set the reselection priority field, so that the terminal initiates cell reselection in time or reduces power consumption; after the terminal autonomously constructs a neighbor relation, the valid version of the current serving cell SIB becomes the valid version of the SIB of the current serving cell after autonomously constructing a neighbor relation; The measuring unit is configured to periodically measure the SSB signal strength and quality of the autonomously constructed neighbor; The reselection condition judging unit is configured to judge whether there is a neighbor meeting the reselection condition; If yes, the neighbor meeting the reselection condition is taken as a reselection candidate cell; if no, and the current serving cell still meets the camping condition, the measuring unit continues to perform measurement; if no, and the current serving cell does not meet the camping condition, but there is one or more NTN neighbor not meeting the reselection condition and whose remaining service time has not expired, these neighbors are considered to meet the reselection condition, and these neighbors are taken as reselection candidate cells; The reselecting unit is configured to initiate reselection to the cell with the highest ranking in the reselection candidate cells.

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