Cell access method, electronic device, and chip system

Abstract

The present application belongs to the technical field of communications. Disclosed are a cell access method, an electronic device, and a chip system. The method comprises: an electronic device receiving a measurement configuration message sent by a first cell; measuring the signal strength and signal quality of a second cell; every first preset duration, on the basis of the signal quality of the second cell measured within the first preset duration, processing the signal strength of the second cell to obtain target signal strength of the second cell; sending to the first cell a measurement report message containing the target signal strength of the second cell greater than a signal strength threshold; and then, the electronic device receiving a handover command sent by the first cell. In the present application, the second cell to which the first cell instructs the electronic device to be handed over is a second cell having good overall signal strength and signal quality, thereby allowing for a high success rate of the electronic device accessing the second cell and thus improving the success rate of a network fallback procedure.

Description

Cell access method, electronic device, and chip system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 15, 2023, with application number 202311739770.3 and application name “Cell Access Method, Electronic Device and Chip System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a cell access method, electronic equipment, and chip system. Background Art

[0003] When user equipment (UE) supports the fifth generation mobile networks (5G) standard, the UE typically resides on the 5G network. In this case, if the UE does not support voice over new radio (VONR) calls, the UE must use the evolved packet system fallback (EPSFB) technology to fall back from the 5G network to the fourth generation mobile networks (4G) network to use voice over long term evolution (VOLTE) calls.

[0004] Currently, after the EPSFB process begins, the 5G cell to which the UE is currently connected sends a measurement configuration message to the UE. After receiving the measurement configuration message, the UE measures the signal strength of one or more 4G cells and reports it to the 5G cell. The 5G cell then selects a 4G cell based on the signal strength of the one or more 4G cells and sends a handover command to the UE, instructing the UE to handover to this 4G cell. After receiving the handover command, the UE accesses the 4G cell and performs a tracking area update (TAU) to implement the EPSFB process.

[0005] However, in actual situations, due to various factors, the EPSFB process is prone to failure.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a cell access method, electronic device, and chip system, which can improve the success rate of the network fallback process.

[0008] In the first aspect, a cell access method is provided. In the method, an electronic device receives a measurement configuration message sent by a first cell, and the measurement configuration message is used to indicate the measurement of the signal strength of a neighboring cell of a different system. Afterwards, the electronic device measures the signal strength and signal quality of the second cell. At intervals of a first preset time duration, the electronic device processes the signal strength of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time duration to obtain the target signal strength of the one or more second cells. The electronic device sends a measurement report message to the first cell, and the measurement report message includes the target signal strength of the second cell whose target signal strength in the one or more second cells is higher than the signal strength threshold. Afterwards, if the electronic device receives a switching command sent by the first cell, it accesses a second cell indicated by the switching command.

[0009] The second cell is a different system neighboring cell of the first cell. The mobile communication technology standards supported by the first cell and the second cell are different. In addition, the mobile communication technology standard supported by the first cell (which may be referred to as the first mobile communication technology standard) is higher than the mobile communication technology standard supported by the second cell (which may be referred to as the second mobile communication technology standard). For example, the first cell supports the 5G standard, and the second cell supports the 4G standard. For another example, the first cell supports the 4G standard, and the second cell 300 supports the 3G standard. In this application, the network based on the first mobile communication technology standard is referred to as the first network, and the network based on the second mobile communication technology standard is referred to as the second network.

[0010] Optionally, the signal strength of a cell in the present application may be the RSRP of the cell. Of course, the signal strength of a cell may also be represented by other characteristics of the cell signal, which is not limited in the present application.

[0011] Optionally, the signal quality of a cell in the present application may be the RSRQ or SINR of the cell, etc. Of course, the signal quality of a cell may also be jointly represented by two or more items, namely, the RSRQ and SINR of the cell, which is not limited in the present application.

[0012] The target signal strength of a second cell not only reflects the signal strength of the second cell, but also its signal quality. In other words, the target signal strength of a second cell reflects the combined signal strength and signal quality of the second cell. In other words, if the target signal strength of one second cell is higher than that of another second cell, it means that the signal strength and signal quality of the first second cell are superior to those of the other second cell overall.

[0013] In the present application, since the target signal strength of the second cell can reflect the comprehensive level of the signal strength and signal quality of the second cell, after receiving the measurement report message sent by the electronic device, the first cell instructs the electronic device to switch to the second cell through the switching command, which is a second cell with relatively good signal strength and signal quality overall. Therefore, the electronic device has a higher success rate in accessing this second cell, thereby improving the success rate of the network fallback process. In the present application, the target signal strength of a cell is relative to the actual signal strength measured by the cell. The target signal strength can be the result obtained after some processing based on the actual signal strength. The target signal strength can be greater than or less than the actual signal strength.

[0014] As an example, before the electronic device receives the measurement configuration message sent by the first cell, it may receive an invite message sent by the first cell; or, send an invite message to the first cell.

[0015] Optionally, the electronic device does not support calls through the first network. In this case, whether the electronic device sends an invite message to the first cell or the first cell sends an invite message to the electronic device, since the electronic device does not support calls through the first network, a network fallback process will be triggered, that is, a process of falling back from the first network to the second network will be triggered so that the electronic device can make subsequent calls through the second network.

[0016] For example, when the first network is a 5G network and the second network is a 4G network, the network fallback process may be an EPSFB process. For another example, when the first network is a 4G network and the second network is a 3G network, the network fallback process may be a CSFB process.

[0017] As an example, the electronic device processes the signal strength of one or more second cells based on the signal quality of the one or more second cells measured within the first preset time period to obtain the target signal strength of the one or more second cells. The operation may be: determining the weight corresponding to each second cell based on the signal quality of each second cell in the one or more second cells; and multiplying the signal strength of each second cell by the corresponding weight to obtain the target signal strength of each second cell.

[0018] In the present application, the signal strength of each second cell is weighted according to the signal quality of each second cell in the one or more second cells to obtain a target signal strength for each second cell. In this way, the target signal strength of each second cell can reflect the signal quality to a certain extent while primarily reflecting the signal strength.

[0019] As an example, the operation of the electronic device sending the measurement report message to the first cell may be: for any second cell among the one or more second cells, if the target signal strength of the second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold, then sending the measurement report message including the target signal strength of the second cell to the first cell. In addition, if the target signal strength of the second cell is not higher than the signal strength threshold and / or if the signal quality of the second cell is lower than the signal quality threshold, then not sending the measurement report message including the target signal strength of the second cell to the first cell.

[0020] In the present application, if the electronic device receives the measurement configuration message and the measured signal quality of all second cells is lower than the signal quality threshold, then in the present application, the electronic device will not report the target signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will not send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it times out and does not receive the measurement report message sent by the electronic device, it will send a redirection message to the first cell to trigger the electronic device to perform the redirection process. Since the electronic device can select a suitable second cell to access when executing the redirection process, the access success rate is relatively high, thereby improving the success rate of the network fallback process.

[0021] As an example, the operation of the electronic device sending a measurement report message to the first cell may be: if there are no multiple specific cells in the one or more second cells whose target signal strength is higher than the signal strength threshold and the difference in target signal strength is less than a preset difference value, then the measurement report message is sent to the first cell.

[0022] Optionally, if the multiple specific cells exist in the one or more second cells, then when the electronic device is in a preset mobile state, the signal strength and signal quality of the multiple specific cells are remeasured after the second preset time period, and the signal strength of the multiple specific cells is processed according to the signal quality of the multiple specific cells to obtain the target signal strength of the multiple specific cells. For any specific cell among the multiple specific cells, if the target signal strength of this specific cell increases, a measurement report message including the target signal strength of this specific cell is sent to the first cell; if the target signal strength of this specific cell remains unchanged or decreases, a measurement report message including the target signal strength of this specific cell is not sent to the first cell.

[0023] In the present application, when the electronic device is in a preset mobile state, if it is found that there are multiple specific cells with high target signal strength and the same or similar target signal strength, it will delay until the target signal strength of the multiple specific cells changes, and then report the target signal strength of the specific cell with increased target signal strength to the first cell. Since the target signal strength of the second cell located in front of the moving direction of the electronic device increases with the movement of the electronic device compared to the second cell located behind the moving direction of the electronic device, the specific cell reported by the electronic device to the first cell is most likely the second cell located in front of the moving direction of the electronic device. In this case, the second cell indicated by the first cell through the handover command is most likely a second cell located in front of the moving direction of the electronic device. Then, as the electronic device moves, the target signal strength of this second cell will become stronger and stronger, so the electronic device has a higher success rate in accessing this second cell, thereby improving the success rate of the network fallback process.

[0024] Optionally, if the multiple specific cells exist in the one or more second cells, then when the electronic device is in a preset mobile state, the signal strength and signal quality of the multiple specific cells are remeasured after the second preset time period, and the signal strength of the multiple specific cells is processed according to the signal quality of the multiple specific cells to obtain the target signal strength of the multiple specific cells. For any specific cell among the multiple specific cells, if the target signal strength of this specific cell increases and the signal quality is not lower than the signal quality threshold, a measurement report message including the target signal strength of this specific cell is sent to the first cell; if the target signal strength of this specific cell remains unchanged or decreases, and / or if the signal quality of this specific cell is lower than the signal quality threshold, a measurement report message including the target signal strength of this specific cell is not sent to the first cell.

[0025] In the present application, if the electronic device receives the measurement configuration message and the measured signal quality of all second cells is lower than the signal quality threshold, then in the present application, the electronic device will not report the target signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will not send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it times out and does not receive the measurement report message sent by the electronic device, it will send a redirection message to the first cell to trigger the electronic device to perform the redirection process. Since the electronic device can select a suitable second cell to access when executing the redirection process, the access success rate is relatively high, thereby improving the success rate of the network fallback process.

[0026] In one possible manner, if the electronic device fails to access a second cell indicated by the handover command, an RLF process is triggered. Afterwards, an RRC connection reestablishment request message may be sent to the target cell, where the target cell is the second cell. The RRC connection reestablishment message sent by the target cell is received, SRB1 is configured according to the SRB1 configuration information carried in the RRC connection reestablishment message, and an RRC connection reestablishment completion message is sent to the target cell. If the electronic device does not receive an RRC reconfiguration message for configuring SRB2 sent by the target cell after a third preset time duration of sending the RRC connection reestablishment completion message, a TAU is performed through SRB1.

[0027] In this application, after the electronic device sends an RRC connection reestablishment complete message to the target cell, if the electronic device does not receive an RRC reconfiguration message from the target cell for configuring SRB2 within a third preset time period, the electronic device can directly perform a TAU over SRB1. This ensures the normal execution of the TAU and improves the success rate of related network fallback processes.

[0028] In another possible manner, if the electronic device fails to access a second cell indicated by the handover command, the RLF process is triggered. Afterwards, an RRC connection reestablishment request message can be sent to the first target cell, where the first target cell is the second cell. The RRC connection reestablishment message sent by the first target cell is received; and an RRC connection reestablishment completion message is sent to the first target cell. If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the first target cell after the fourth preset time length of sending the RRC connection reestablishment completion message, the RLF process is triggered, and the RRC connection reestablishment process is performed with the second target cell, where the second target cell is the second cell.

[0029] In the present application, after the electronic device sends an RRC connection reestablishment completion message to the first target cell, if the electronic device still does not receive the RRC reconfiguration message for configuring SRB2 from the first target cell after a fourth preset time period, the electronic device will no longer wait for the first target cell to send the RRC reconfiguration message, but will directly trigger the RLF process to switch cells as soon as possible to perform the RRC connection reestablishment process. In this way, the electronic device can avoid the long and meaningless waiting of the electronic device during the RRC connection reestablishment process, thereby improving the success rate of related network fallback processes, etc.

[0030] In a second aspect, a cell access method is provided. In this method, an electronic device receives a measurement configuration message sent by a first cell, where the measurement configuration message is used to instruct the measurement of the signal strength of a neighboring cell of an inter-system. Subsequently, the signal strength and signal quality of a second cell are measured, where the second cell is an inter-system neighboring cell of the first cell. If the signal quality of the second cell is lower than a signal quality threshold, a measurement report message is not sent to the first cell. Subsequently, if the electronic device receives a redirection message sent by the first cell, it accesses a second cell.

[0031] If the signal quality of a second cell is not lower than the signal quality threshold, it means that the signal quality of the second cell is good; if the signal quality of a second cell is lower than the signal quality threshold, it means that the signal quality of the second cell is poor.

[0032] In this application, if the signal quality of the second cell measured by the electronic device is lower than the signal quality threshold, the electronic device does not send a measurement report message to the first cell to trigger the first cell to instruct the electronic device to perform a redirection process. Because the electronic device can select a suitable second cell to access when performing the redirection process, the access success rate is relatively high, thereby improving the success rate of the network fallback process.

[0033] As an example, the operation of the electronic device accessing a second cell may include: the electronic device accessing a second cell having a signal strength greater than a signal strength threshold and a signal quality no less than a signal quality threshold. Since the signal strength and signal quality of the second cell are relatively good, the success rate of the electronic device accessing the second cell is relatively high.

[0034] Alternatively, the electronic device accesses a second cell of a preset cell type. The preset cell type can be pre-set. The preset cell type is a cell type with a higher access success rate. Thus, the electronic device has a higher success rate when accessing the second cell of the preset cell type.

[0035] For example, the preset cell type can be a high-speed rail cell. Of course, the preset cell type can also be other cell types, and this application does not limit this. Among them, the high-speed rail cell is a number of cells set up along the high-speed rail line, which is mainly used to solve the problem of poor signal of the electronic devices of people riding the high-speed rail during the high-speed rail. Since the high-speed rail cell is generally dedicated, it will not be too congested. In addition, some operators will isolate the high-speed rail cell and the non-high-speed rail cell, so it is not easy to have problems when accessing the high-pass cell. Therefore, during the high-speed rail journey, the electronic devices of people riding the high-speed rail have a relatively high success rate in accessing the high-speed rail cell, and the network experience after accessing the high-speed rail cell is also better.

[0036] As an example, after the electronic device measures the signal strength and signal quality of the second cell, it can also send a measurement report message to the first cell if the signal strength of the second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold. The measurement report message includes the signal strength of the second cell.

[0037] In one possible approach, if the electronic device fails to access a second cell after receiving a redirection message, an RLF process is triggered. Subsequently, an RRC connection reestablishment request message may be sent to the target cell, where the target cell is the second cell. The RRC connection reestablishment message sent by the target cell is received, SRB1 is configured according to the SRB1 configuration information carried in the RRC connection reestablishment message, and an RRC connection reestablishment complete message is sent to the target cell. If the electronic device does not receive an RRC reconfiguration message for configuring SRB2 sent by the target cell after a third preset time duration of sending the RRC connection reestablishment complete message, a TAU is performed via SRB1.

[0038] In another possible manner, if the electronic device fails to access a second cell after receiving the redirection message, the RLF process is triggered. Afterwards, an RRC connection reestablishment request message can be sent to the first target cell, where the first target cell is the second cell. The RRC connection reestablishment message sent by the first target cell is received; and an RRC connection reestablishment completion message is sent to the first target cell. If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the first target cell after the fourth preset time length of sending the RRC connection reestablishment completion message, the RLF process is triggered, and the RRC connection reestablishment process is performed with the second target cell, where the second target cell is the second cell.

[0039] According to a third aspect, a cell access method is provided. In this method, an electronic device receives a measurement configuration message sent by a first cell, and the measurement configuration message is used to indicate the measurement of the signal strength of a neighboring cell of an alien system. Afterwards, the signal strength of the second cell is measured, and the second cell is a neighboring cell of an alien system of the first cell. If there are multiple specific cells in the measured second cell whose signal strength is higher than the signal strength threshold and the difference in signal strength is less than a preset difference, and if the electronic device is in a preset mobile state, the signal strength of the multiple specific cells is remeasured after a second preset time length. After re-measuring the signal strength of the multiple specific cells, a measurement report message is sent to the first cell, and the measurement report message includes the signal strength of the specific cell with increased signal strength among the multiple specific cells. Afterwards, if the electronic device receives a switching command sent by the first cell, it accesses a second cell indicated by the switching command.

[0040] If the electronic device is in a preset moving state, the signal strength of the second cell measured by the electronic device will change relatively quickly. In this case, the signal strengths of the multiple specific cells are the same or similar, indicating that the electronic device is very likely moving to a relatively middle position of the multiple specific cells, but will soon move to other positions. In other words, although the signal strengths of the multiple specific cells are currently the same or similar, they will soon change. It can be understood that the signal strength of the specific cell located in front of the moving direction of the electronic device among the multiple specific cells will soon become stronger, while the signal strength of the specific cell located behind the moving direction of the electronic device will soon become weaker.

[0041] In this case, if the signal strengths of the multiple specific cells are directly reported to the first cell, then because the signal strengths of the multiple specific cells are the same or similar, the second cell selected by the first cell may be a second cell located behind the direction of movement of the electronic device. When the electronic device is in the preset moving state, the signal strength of this second cell will quickly weaken, and the electronic device may fail to access this second cell in subsequent attempts.

[0042] Therefore, in order to ensure the success rate of the subsequent electronic device accessing the second cell, the embodiment of the present application does not first report the signal strengths of the multiple specific cells to the first cell, but remeasures the signal strengths of the multiple specific cells after the second preset time period. Due to the passage of the second preset time period, the signal strengths of the multiple specific cells that previously had the same or similar signal strengths have changed, wherein the signal strength of the specific cell located in front of the electronic device in the direction of movement has become stronger, while the signal strength of the specific cell located behind the electronic device in the direction of movement has become weaker.

[0043] In the present application, when the electronic device is in a preset mobile state, if it finds that there are multiple specific cells with high signal strength and the same or similar signal strength, it will delay until the signal strength of the multiple specific cells changes, and then report the signal strength of the specific cell with increased signal strength to the first cell. Since the signal strength of the second cell located in front of the moving direction of the electronic device increases with the movement of the electronic device compared to the second cell located behind the moving direction of the electronic device, the specific cell reported by the electronic device to the first cell is most likely the second cell located in front of the moving direction of the electronic device. In this case, the second cell indicated by the first cell through the handover command is most likely a second cell located in front of the moving direction of the electronic device. Then, as the electronic device moves, the signal strength of this second cell will become stronger and stronger, so the electronic device has a higher success rate in accessing this second cell, thereby improving the success rate of the network fallback process.

[0044] As an example, the operation of the electronic device measuring the signal strength of the second cell may be: measuring the signal strength and signal quality of the second cell. In this case, the operation of the electronic device sending a measurement report message to the first cell may be: for any specific cell among the multiple specific cells, if the signal strength of this specific cell increases and the signal quality of this specific cell is not lower than the signal quality threshold, then sending a measurement report message including the signal strength of this specific cell to the first cell. In addition, if the signal strength of this specific cell remains unchanged or decreases, and / or if the signal quality of this specific cell is lower than the signal quality threshold, then not sending a measurement report message including the signal strength of this specific cell to the first cell.

[0045] In one possible manner, if the electronic device fails to access a second cell indicated by the handover command, an RLF process is triggered. Afterwards, an RRC connection reestablishment request message may be sent to the target cell, where the target cell is the second cell. The RRC connection reestablishment message sent by the target cell is received, SRB1 is configured according to the SRB1 configuration information carried in the RRC connection reestablishment message, and an RRC connection reestablishment completion message is sent to the target cell. If the electronic device does not receive an RRC reconfiguration message for configuring SRB2 sent by the target cell after a third preset time duration of sending the RRC connection reestablishment completion message, a TAU is performed through SRB1.

[0046] In another possible manner, if the electronic device fails to access a second cell indicated by the handover command, the RLF process is triggered. Afterwards, an RRC connection reestablishment request message can be sent to the first target cell, where the first target cell is the second cell. The RRC connection reestablishment message sent by the first target cell is received; and an RRC connection reestablishment completion message is sent to the first target cell. If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the first target cell after the fourth preset time length of sending the RRC connection reestablishment completion message, the RLF process is triggered, and the RRC connection reestablishment process is performed with the second target cell, where the second target cell is the second cell.

[0047] In a fourth aspect, a cell access method is provided. In this method, if the electronic device triggers the RLF process, it sends an RRC connection reestablishment request message to the target cell. Thereafter, the electronic device receives an RRC connection reestablishment message sent by the target cell, where the RRC connection reestablishment message carries SRB1 configuration information. The electronic device configures SRB1 according to the SRB1 configuration information and sends an RRC connection reestablishment completion message to the target cell. If the electronic device does not receive an RRC reconfiguration message for configuring SRB2 sent by the target cell after sending the RRC connection reestablishment completion message for a third preset time, a TAU is performed through SRB1.

[0048] In this application, after the electronic device sends an RRC connection reestablishment complete message to the target cell, if the electronic device does not receive an RRC reconfiguration message from the target cell for configuring SRB2 within a third preset time period, the electronic device can directly perform a TAU over SRB1. This ensures the normal execution of the TAU and improves the success rate of related network fallback processes.

[0049] As an example, if the electronic device receives an RRC reconfiguration message for configuring SRB2 from the target cell within the third preset duration of sending the RRC connection reestablishment complete message, the electronic device configures SRB2 according to the SRB2 configuration information in the RRC reconfiguration message and performs a TAU using the SRB2. At this point, the TAU can proceed normally, and related network fallback processes, etc., can also continue normally.

[0050] As an example, an electronic device may receive a handover command from a first cell, which instructs handover to a second cell. The electronic device then accesses the second cell. If access to the second cell fails, an RLF procedure is triggered. In this case, the target cell is the second cell.

[0051] In a fifth aspect, a cell access method is provided, in which, if an electronic device triggers an RLF process, an RRC connection reestablishment request message is sent to a target cell. Subsequently, an RRC connection reestablishment message is received from a first target cell. An RRC connection reestablishment completion message is sent to the first target cell. If the electronic device does not receive an RRC reconfiguration message for configuring SRB2 from the first target cell after a fourth preset time duration of sending the RRC connection reestablishment completion message, the RLF process is triggered, and an RRC connection reestablishment process is performed with the second target cell.

[0052] In the present application, after the electronic device sends an RRC connection reestablishment completion message to the first target cell, if the electronic device still does not receive the RRC reconfiguration message for configuring SRB2 from the first target cell after a fourth preset time period, the electronic device will no longer wait for the first target cell to send the RRC reconfiguration message, but will directly trigger the RLF process to switch cells as soon as possible to perform the RRC connection reestablishment process. In this way, the electronic device can avoid the long and meaningless waiting of the electronic device during the RRC connection reestablishment process, thereby improving the success rate of related network fallback processes, etc.

[0053] As an example, if the electronic device receives an RRC reconfiguration message for configuring SRB2 from the first target cell after the fourth preset time period of sending the RRC connection reestablishment complete message, a TAU is performed. At this time, the TAU can proceed normally, and its related network fallback processes, etc. can also continue normally.

[0054] As an example, an electronic device may receive a handover command from a first cell, which instructs handover to a second cell. The electronic device then accesses the second cell. If access to the second cell fails, an RLF procedure is triggered. In this case, the first target cell and the second target cell are both second cells.

[0055] In a sixth aspect, a chip system is provided, which is applied to an electronic device. The chip system includes one or more processors, which are used to call computer instructions to enable the electronic device to execute the above-mentioned cell access method.

[0056] In a seventh aspect, a cell access device is provided, which has the function of implementing the above-mentioned cell access method. The cell access device includes at least one module, and the at least one module is used to implement the above-mentioned cell access method.

[0057] In an eighth aspect, an electronic device is provided, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the above-mentioned cell access method when executed by the processor.

[0058] In a ninth aspect, a computer-readable storage medium is provided, wherein instructions are stored in the computer-readable storage medium, and when the computer-readable storage medium is run on the computer, the computer executes the above-mentioned cell access method.

[0059] In a tenth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the above-mentioned cell access method.

[0060] The technical effects obtained in the above-mentioned sixth to tenth aspects are similar to the technical effects obtained by the corresponding technical means in the above-mentioned first to fifth aspects, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG1 is a schematic diagram of a communication system provided in an embodiment of the present application;

[0062] FIG2 is a flow chart of a cell switching process provided by an embodiment of the present application;

[0063] FIG3 is a flow chart of a cell access method provided in an embodiment of the present application;

[0064] FIG4 is a schematic diagram of another communication system provided in an embodiment of the present application;

[0065] FIG5 is a schematic diagram of a cell access process provided in an embodiment of the present application;

[0066] FIG6 is a flowchart of another cell access method provided in an embodiment of the present application;

[0067] FIG7 is a schematic diagram of another cell access process provided in an embodiment of the present application;

[0068] FIG8 is a flowchart of another cell access method provided in an embodiment of the present application;

[0069] FIG9 is a flowchart of another cell access method provided in an embodiment of the present application;

[0070] FIG10 is a flowchart of another cell access method provided in an embodiment of the present application;

[0071] FIG11 is a flowchart of another cell access method provided in an embodiment of the present application;

[0072] FIG12 is a flowchart of another cell access method provided in an embodiment of the present application;

[0073] FIG13 is a flowchart of another cell access method provided in an embodiment of the present application;

[0074] FIG14 is a schematic diagram of a TAU process provided in an embodiment of the present application;

[0075] FIG15 is a flowchart of another cell access method provided in an embodiment of the present application;

[0076] FIG16 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0077] FIG17 is a software structure block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0078] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0079] It should be understood that the “multiple” mentioned in this application refers to two or more. In the description of this application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate the clear description of the technical solution of this application, words such as “first” and “second” are used to distinguish between identical or similar items with basically the same functions and effects. Those skilled in the art can understand that words such as “first” and “second” do not limit the quantity and execution order, and words such as “first” and “second” do not necessarily limit them to be different.

[0080] The phrases "one embodiment" or "some embodiments" described in this application mean that the specific features, structures, or characteristics described in that embodiment are included in one or more embodiments of the application. Thus, the phrases "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" that appear in different places in this application do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. In addition, the terms "including," "comprising," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized.

[0081] The following describes the system architecture involved in the embodiments of the present application.

[0082] Figure 1 is a schematic diagram of a communication system provided by an embodiment of the present application. Referring to Figure 1 , the communication system may include an electronic device 100, a first cell 200, and a second cell 300. The number of the second cell 300 may be one or more.

[0083] The electronic device 100 is within the coverage of the first cell 200 and the coverage of the second cell 300. The electronic device 100 can access the first cell 200 or the second cell 300.

[0084] The electronic device 100 may also be referred to as a UE. The electronic device 100 may support multiple mobile communication technology standards, such as the second generation mobile network (2G) standard, the third generation mobile network (3G) standard, the 4G standard, the 5G standard, etc. The 4G standard may also be referred to as the long term evolution (LTE) standard.

[0085] By way of example, the electronic device 100 may be a mobile terminal (MT), a mobile station (MS), a mobile unit (MU), a wireless unit, a remote unit, a user agent, a mobile client, etc. For example, the electronic device 100 may be a mobile phone, a tablet computer, a wearable device, a digital camera, an in-vehicle device, an augmented reality (AR) device, a virtual reality (VR) device, a notebook computer, an ultra-mobile personal computer (UMPC), a netbook, a personal digital assistant (PDA), a laptop computer, etc., and the embodiments of the present application are not limited thereto.

[0086] The second cell 300 is a neighboring cell of a different system of the first cell 200. That is, the mobile communication technology standards supported by the first cell 200 and the second cell 300 are different. In addition, the mobile communication technology standard supported by the first cell 200 is higher than the mobile communication technology standard supported by the second cell 300. For example, the first cell 200 supports the 5G standard. In this case, the first cell 200 can be called a 5G cell; the second cell 300 supports the 4G standard. In this case, the second cell 300 can be called a 4G cell. For another example, the first cell 200 supports the 4G standard. In this case, the first cell 200 can be called a 4G cell; the second cell 300 supports the 3G standard. In this case, the second cell 300 can be called a 3G cell. Optionally, the 5G cell can also be called a new radio (NR) cell. The 4G cell can also be called an LTE cell.

[0087] When the electronic device 100 accesses one of the first cell 200 and the second cell 300, the electronic device 100 can communicate with this cell. When the electronic device 100 communicates with this cell, it means communicating with the base station of this cell. For example, when the electronic device 100 accesses a 3G cell, the electronic device 100 communicates with the base station (node ​​B, NB) of the 3G cell; when the electronic device 100 accesses a 4G cell, the electronic device 100 communicates with the evolved base station (evolutional node B, eNB) of the 4G cell; when the electronic device 100 accesses a 5G cell, the electronic device 100 communicates with the next generation base station (next generation node B, gNB) of the 5G cell.

[0088] It should be noted that in the embodiment of the present application, the electronic device 100 may support a first mobile communication technology standard and a second mobile communication technology standard, where the first mobile communication technology standard is higher than the second mobile communication technology standard. The first mobile communication technology standard is the mobile communication technology standard supported by the first cell 200, and the second mobile communication technology standard is the mobile communication technology standard supported by the second cell 300. In the embodiment of the present application, a network based on the first mobile communication technology standard is referred to as a first network, and a network based on the second mobile communication technology standard is referred to as a second network.

[0089] The first mobile communication technology standard may be the highest mobile communication technology standard among multiple mobile communication technology standards supported by the electronic device 100. In this case, the electronic device 100 should normally stay in the first network as much as possible to ensure a high residency ratio of the first network.

[0090] In some embodiments, the electronic device 100 does not support calls over the first network. In this case, when a call is needed, the electronic device 100 can fall back from the first network to the second network to make the call. When the electronic device 100 falls back from the first network to the second network, it switches from the first cell 200 to the second cell 300.

[0091] For example, the electronic device 100 can support up to the 5G standard. In this case, the 5G standard is the first mobile communication technology standard, and the 5G network is the first network; the 4G standard is the second mobile communication technology standard, and the 4G network is the second network. In this case, the electronic device 100 should normally reside in the 5G network as much as possible. However, the electronic device 100 does not support calls through the 5G network, that is, the electronic device 100 does not support VONR calls. Then the electronic device 100 can use EPSFB technology to fall back from the 5G network to the 4G network to use VOLTE calls when a call is needed, wherein the electronic device 100 will switch from the 5G cell to the 4G cell during the EPSFB process.

[0092] For another example, the electronic device 100 can support up to the 4G standard. In this case, the 4G standard is the first mobile communication technology standard, and the 4G network is the first network; the 3G standard is the second mobile communication technology standard, and the 3G network is the second network. In this case, the electronic device 100 should normally reside in the 4G network as much as possible. However, the electronic device 100 does not support calls through the 4G network, that is, the electronic device 100 does not support VOLTE calls. Then the electronic device 100 can use the circuit switched fallback (CSFB) technology to fall back from the 4G network to the 3G network to use 3G calls when a call is needed, wherein the electronic device 100 will switch from the 4G cell to the 3G cell during the CSFB process.

[0093] Next, the cell switching process during EPSFB is exemplified by taking the first network being a 5G network, the first cell being a 5G cell, the second network being a 4G network, and the second cell being a 4G cell as an example. It is understandable that the cell switching process during CSFB when the first network is a 4G network, the first cell is a 4G cell, the second network is a 3G network, and the second cell is a 3G cell is similar, and this embodiment of the present application will not be further described.

[0094] FIG2 is a flow chart of a cell handover process provided by an embodiment of the present application. Referring to FIG2 , the cell handover process may include the following steps 201 to 217 .

[0095] Step 201: The electronic device accesses a 5G cell.

[0096] When an electronic device accesses a 5G cell, the electronic device is in a radio resource control (RRC) connected state. At this time, the electronic device resides in the 5G cell.

[0097] In some embodiments, the electronic device does not support VONR calls.

[0098] Step 202: The 5G cell sends an invite message to the electronic device.

[0099] The 5G cell sends an invite message to the electronic device, which means that the electronic device is called by the calling device as the called device.

[0100] It should be noted that in step 202, the electronic device may also send an invite message to the 5G cell. In this case, the electronic device acts as the calling device to call the called device.

[0101] Whether the 5G cell sends an invite message to the electronic device, or the electronic device sends an invite message to the 5G cell, since the electronic device does not support VONR calls, the EPSFB process will be triggered. The EPSFB process may include the following steps 203 to 217.

[0102] Step 203: The 5G cell sends a measurement configuration message to the electronic device.

[0103] For example, the measurement configuration message may be an RRC connection reconfiguration message carrying a measurement configuration (measConfig) information element.

[0104] The measurement configuration message is used to instruct the electronic device to measure the signal strength of a neighboring cell of a different system.

[0105] For example, the measurement configuration message may include B1 event information. The B1 event information may include a threshold value for the B1 event. The B1 event is used to indicate that the signal strength of a neighboring cell of an alien system is greater than the threshold value. In this case, the measurement configuration message is used to instruct the electronic device to report a measurement report (MR) message when the signal strength of a neighboring cell of an alien system is greater than the threshold value.

[0106] Step 204: The electronic device measures the signal strength of the 4G cell.

[0107] The 4G cell is a neighboring cell of a different system than the 5G cell to which the electronic device is currently connected.

[0108] If an electronic device is within the coverage of a 4G cell, it can measure the signal strength of the 4G cell.

[0109] Step 205: The electronic device sends a measurement report message to the 5G cell.

[0110] When an electronic device measures that the signal strength of a 4G cell is higher than a threshold, it can send a measurement report message to the 5G cell.

[0111] The measurement report message includes the physical cell identifier (PCI) and signal strength of the 4G cell whose signal strength is higher than the threshold.

[0112] It is assumed here that the electronic device is within the coverage of 4G cell A and within the coverage of 4G cell B. The electronic device measures the signal strength of 4G cell A, and when the signal strength of 4G cell A is higher than the threshold, sends a measurement report message including the PCI and signal strength of 4G cell A to the 5G cell. Furthermore, the electronic device measures the signal strength of 4G cell B, and when the signal strength of 4G cell B is higher than the threshold, sends a measurement report message including the PCI and signal strength of 4G cell B to the 5G cell.

[0113] The 5G cell may select a 4G cell based on the signal strength of the 4G cells included in the measurement report message sent by the electronic device, for example, the 4G cell with the highest signal strength may be selected. The 5G cell may then instruct the electronic device to switch to the 4G cell, as described below.

[0114] Step 206: The 5G cell sends a handover command to the electronic device.

[0115] For example, the handover command may be an RRC connection reconfiguration message carrying a mobility control (mobilityControlInfo) information element.

[0116] Optionally, the handover command may include wireless parameters required to be used when handing over to the 4G cell, such as PCI and radio bearer (RB) configuration information of the 4G cell to be handed over.

[0117] The RB configuration information is configuration information related to the RB. For example, the RB configuration information may include configuration information related to signaling radio bearer (SRB) 1, SRB2, and data radio bearer (DRB).

[0118] The SRB is the actual transmission channel for signaling messages. SRB1 is used to carry RRC messages and can also carry some non-access stratum (NAS) messages. SRB2 is used to carry NAS messages. The DRB is the actual transmission channel for user data.

[0119] It is assumed here that the handover command includes wireless parameters required for handover to 4G cell A, that is, the handover command is used to instruct handover to 4G cell A. Then, the electronic device may reside in 4G cell A after receiving the handover command.

[0120] Step 207: The electronic device attempts to access 4G cell A, but fails to do so.

[0121] Optionally, the electronic device may attempt to access 4G cell A according to the wireless parameters included in the handover command.

[0122] For example, the electronic device may attempt to access 4G cell A using a random access method (including but not limited to a non-contention random access method) according to the wireless parameters included in the handover command.

[0123] It should be noted that although the signal strength of 4G cell A is relatively high, the signal quality of 4G cell A may be relatively poor. When the signal quality of 4G cell A is relatively poor, the electronic device may fail to access 4G cell A when attempting to access the 4G cell A.

[0124] Step 208: The electronic device triggers a radio link failure (RLF) process and selects 4G cell B.

[0125] The RLF process involves a cell selection process and an RRC connection re-establishment process, which aims to re-establish the RRC connection. After triggering the RLF process, the electronic device can first select a 4G cell, assuming 4G cell B is selected. The electronic device can then reside in 4G cell B and establish an RRC connection with 4G cell B, as described below.

[0126] Step 209: The electronic device sends an RRC connection reestablishment request message to 4G cell B.

[0127] Optionally, the RRC connection reestablishment request message may carry a reestablishment reason. For example, the reestablishment reason triggered by RLF may be "otherFailure".

[0128] Step 210: 4G cell B sends an RRC connection reestablishment message to the electronic device.

[0129] After receiving the RRC connection reestablishment request message, 4G cell B may send an RRC connection reestablishment message to the electronic device. For example, the RRC connection reestablishment message may carry SRB1 configuration information. The SRB1 configuration information is configuration information related to SRB1.

[0130] Step 211: The electronic device sends an RRC connection reestablishment complete message to 4G cell B.

[0131] After the electronic device receives the RRC connection reestablishment message sent by 4G cell B, it can configure SRB1 according to the SRB1 configuration information in the RRC connection reestablishment message, and can send an RRC connection reestablishment completion message to 4G cell B through SRB1.

[0132] Because the cell in which the electronic device resides has changed, the electronic device may find that its tracking area (TA) or TA list has changed. A TA list may contain multiple TAs. In this case, after establishing an RRC connection with 4G cell B, the electronic device needs to perform a TAU to notify the network side (including the 4G network access network and core network) of its current TA.

[0133] In related technologies, electronic devices can perform TAU via SRB1 when in RRC idle state. However, in RRC connected state, electronic devices can only perform TAU via SRB2, not SRB1. Therefore, after sending an RRC connection reestablishment complete message to 4G cell B, the electronic device needs to wait for 4G cell B to send an RRC reconfiguration message carrying SRB2 configuration information and DRB configuration information to configure SRB2 and DRB before performing TAU via SRB2.

[0134] However, in some actual scenarios, the following phenomenon occurs: after an electronic device sends an RRC connection reestablishment complete message to 4G cell B, 4G cell B does not send an RRC reconfiguration message carrying SRB2 configuration information and DRB configuration information to the electronic device. Instead, it sends an RRC connection release message to the electronic device after a period of time (generally about 5 seconds). Analysis shows that the reason for this situation may be that after receiving the RRC connection reestablishment complete message sent by the electronic device, 4G cell B does not find that the electronic device uses the RRC connection to transmit data for a long time, so it sends an RRC connection release message to the electronic device.

[0135] Step 212: 4G cell B sends an RRC connection release message to the electronic device.

[0136] Step 213: The electronic device triggers the TAU process.

[0137] After receiving the RRC connection release message, the electronic device releases the RRC connection with 4G cell B. After the RRC connection is released, the electronic device enters the RRC idle state. When the electronic device enters the RRC idle state, the TAU process is triggered.

[0138] After the electronic device triggers the TAU process, it will first establish an RRC connection with 4G cell B, and then perform TAU through SRB1, as described below.

[0139] Step 214: The electronic device sends an RRC connection request message to 4G cell B.

[0140] Step 215: 4G cell B sends an RRC connection setup message to the electronic device.

[0141] After receiving the RRC connection request message sent by the electronic device, 4G cell B may send an RRC connection establishment message to the electronic device. For example, the RRC connection establishment message may carry SRB1 configuration information.

[0142] Step 216: The electronic device sends an RRC connection setup complete message to 4G cell B. The RRC connection setup complete message includes a TAU request message of the NAS layer.

[0143] After the electronic device receives the RRC connection establishment message sent by 4G cell B, it can configure SRB1 according to the SRB1 configuration information in the RRC connection establishment message, and then send the RRC connection establishment completion message to 4G cell B through SRB1.

[0144] For example, the TAU request message may include a tracking area identity (TAI) of the TA where the electronic device is currently located.

[0145] After the electronic device sends the RRC connection establishment completion message to the 4G cell B, the 4G cell B should return a TAU acceptance message of the NAS layer to the electronic device. However, in some actual scenarios, the 4G cell B does not return a TAU acceptance message to the electronic device, but returns a TAU rejection message of the NAS layer to the electronic device, and the attached rejection reason value is #10 implicitly detached. After analysis, the reason for this situation may be: due to the timeout of the fallback timer on the network side (the electronic device falls back from the 5G network to the 4G network), the network side has implicitly detached the electronic device, so a TAU rejection message is returned to the electronic device.

[0146] Step 217: 4G cell B sends a TAU rejection message to the electronic device.

[0147] After receiving the TAU rejection message from 4G cell B, the electronic device can determine that the EPSFB process has failed, resulting in a call failure. This failure occurs when the electronic device is the calling device, and when the electronic device is the called device, it occurs when the called device is the called device. The electronic device can then initiate an attach process to attempt to continue accessing 4G cell B.

[0148] Analysis of the root cause of the above call failure may be that after the electronic device sends the RRC connection reestablishment completion message to 4G cell B in step 211, the electronic device has not received the RRC reconfiguration message sent by 4G cell B carrying SRB2 configuration information and DRB configuration information in order to wait for the RRC reconfiguration message sent by 4G cell B carrying SRB2 configuration information and DRB configuration information, causing the electronic device to wait for too long (i.e., 5 seconds above). If the electronic device waits too long after sending the RRC connection reestablishment completion message to 4G cell B, it will not only cause 4G cell B in step 211 to send an RRC connection release message to the electronic device, but also cause 4G cell B in step 217 to send a TAU rejection message to the electronic device.

[0149] Furthermore, the long wait of the electronic device is also likely to cause the fallback timer of the electronic device to time out. That is, even if 4G cell B returns a TAU acceptance message to the electronic device after step 216, the EPSFB process will fail due to the fallback timer of the electronic device timing out, resulting in call failure.

[0150] As can be seen from the cell handover process described in the embodiment of FIG. 2 , there are two main problems with this process: First, the electronic device attempts to access 4G cell A in step 207 but fails to do so. Second, after the electronic device sends the RRC connection reestablishment completion message to 4G cell B in step 211, the electronic device waits too long.

[0151] To this end, an embodiment of the present application provides a cell access method to solve the above two problems, thereby avoiding EPSFB process failure and improving call success rate.

[0152] The cell access method provided in the embodiment of the present application is explained in detail below.

[0153] In one possible implementation, the cell access method provided in the embodiment of the present application is used to solve the problem in step 207 of the embodiment of Figure 2 above where the electronic device attempts to access 4G cell A but fails to do so. This is described in detail in the embodiment of Figure 3 below.

[0154] FIG3 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG3 , the method includes the following steps:

[0155] Step 301: An electronic device accesses a first cell.

[0156] The first cell has been explained in detail in the embodiment of Figure 1 above, and will not be repeated in this embodiment of the present application.

[0157] When the electronic device accesses the first cell, the electronic device is in an RRC connected state. At this time, the electronic device resides in the first cell.

[0158] Step 302: The electronic device sends an invite message to the first cell, or the first cell sends an invite message to the electronic device.

[0159] When the electronic device sends an invite message to the first cell, the electronic device acts as the calling device to call the called device. When the first cell sends an invite message to the electronic device, the electronic device acts as the called device to be called by the calling device.

[0160] Whether the electronic device sends an invite message to the first cell or the first cell sends an invite message to the electronic device, since the electronic device does not support calls through the first network, it will trigger the network fallback process, that is, trigger the process of falling back from the first network to the second network, so that the electronic device can make subsequent calls through the second network.

[0161] For example, when the first network is a 5G network and the second network is a 4G network, the network fallback process may be an EPSFB process. For another example, when the first network is a 4G network and the second network is a 3G network, the network fallback process may be a CSFB process.

[0162] In the embodiment of the present application, the network fallback process may at least include the following steps 303 to 308.

[0163] Step 303: The first cell sends a measurement configuration message to the electronic device.

[0164] For example, the measurement configuration message may be an RRC connection reconfiguration message carrying a measConfig information element. The measConfig information element may include a measurement frequency point.

[0165] The measurement configuration message is used to instruct the electronic device to measure the signal strength of a neighboring cell of a different system.

[0166] For example, the measurement configuration message may include B1 event information. The B1 event information may include a threshold value for the B1 event. The B1 event is used to indicate that the signal strength of a neighboring cell of an alien system is greater than the threshold value. In this case, the measurement configuration message is used to instruct the electronic device to report a measurement report message when the signal strength of a neighboring cell of an alien system is greater than the threshold value.

[0167] Step 304: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0168] The second cell has been explained in detail in the embodiment of Figure 1 above, and will not be repeated in this embodiment of the present application.

[0169] If the electronic device is within the coverage of a second cell, the second cell is a different-system neighboring cell of the first cell currently accessed by the electronic device. In some embodiments, if the second cell corresponds to the measurement frequency carried in the measurement configuration message, the electronic device can continuously measure the signal strength and signal quality of the second cell.

[0170] Optionally, the signal strength of the cell in the embodiment of the present application may be the reference signal receiving power (RSRP) of the cell. Of course, the signal strength of the cell may also be characterized by other characteristics of the cell signal, which is not limited in the embodiment of the present application.

[0171] Optionally, the signal quality of the cell in the embodiment of the present application may be a reference signal received quality (RSRQ) or a signal to interference plus noise ratio (SINR) of the cell. Of course, the signal quality of the cell may also be jointly characterized by two or more items of the RSRQ and SINR of the cell, which is not limited in the embodiment of the present application.

[0172] In an embodiment of the present application, after receiving a measurement configuration message sent by a first cell, the electronic device can measure not only the signal strength of the second cell but also the signal quality of the second cell. Furthermore, the electronic device can process the signal strength of the second cell based on the signal quality of the second cell and then report it to the first cell, as described below.

[0173] Step 305: After receiving the measurement configuration message, the electronic device processes the signal strength of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time period at intervals of the first preset time period to obtain the target signal strength of the one or more second cells.

[0174] The first preset duration can be pre-set. The first preset duration can be set to be shorter, such as 300 milliseconds, 500 milliseconds, etc., which is not limited in this embodiment of the present application. It should be noted that the first cell sets a timeout after sending the measurement configuration message, and the first preset duration is less than the timeout.

[0175] For ease of description, the signal strength of the second cell measured by the electronic device is referred to as the actual signal strength of the second cell. For one or more second cells measured by the electronic device within the first preset time period, the target signal strength of each of the one or more second cells is obtained by processing the actual signal strength of each second cell with reference to the signal quality of each second cell.

[0176] The target signal strength of a second cell not only reflects the actual signal strength of the second cell, but also the signal quality of the second cell. In other words, the target signal strength of a second cell reflects the combined level of the actual signal strength and signal quality of the second cell. In other words, if the target signal strength of one second cell is higher than that of another second cell, it means that the actual signal strength and signal quality of the first second cell are superior to those of the other second cell overall.

[0177] For example, if the actual signal strength of the second cell A is the same as the actual signal strength of the second cell B, but the signal quality of the second cell A is higher than the signal quality of the second cell B, then the target signal strength of the second cell A will be higher than the target signal strength of the second cell B.

[0178] For another example, if the actual signal strength of the second cell A is lower than the actual signal strength of the second cell B, and the signal quality of the second cell A is also lower than the signal quality of the second cell B, then the target signal strength of the second cell A will be lower than the target signal strength of the second cell B.

[0179] For another example, if the actual signal strength of the second cell A is lower than the actual signal strength of the second cell B, but the signal quality of the second cell A is higher than the signal quality of the second cell B, then the target signal strength of the second cell A and the target signal strength of the second cell B should be determined based on the comprehensive level of the actual signal strength and signal quality of the second cell A and the comprehensive level of the actual signal strength and signal quality of the second cell B.

[0180] Assuming that the actual signal strength of the second cell A is slightly lower than the actual signal strength of the second cell B, and the signal quality of the second cell A is much higher than the signal quality of the second cell B, then the target signal strength of the second cell A will be higher than the target signal strength of the second cell B. Alternatively, assuming that the actual signal strength of the second cell A is much lower than the actual signal strength of the second cell B, and the signal quality of the second cell A is slightly higher than the signal quality of the second cell B, then the target signal strength of the second cell A will be lower than the target signal strength of the second cell B.

[0181] In some embodiments, the operation of step 305 may be: the electronic device determines the weight corresponding to each second cell based on the signal quality of each second cell in the one or more second cells; and multiplies the actual signal strength of each second cell in the one or more second cells by the corresponding weight to obtain the target signal strength of each second cell.

[0182] In this case, the actual signal strength of each second cell is weighted according to the signal quality of each second cell in the one or more second cells to obtain the target signal strength of each second cell. In this way, the target signal strength of each second cell can reflect the signal quality to a certain extent while mainly reflecting the actual signal strength.

[0183] It should be noted that, for any second cell among the one or more second cells, the greater the signal quality of the second cell, the greater the corresponding weight of the second cell; the smaller the signal quality of the second cell, the smaller the corresponding weight of the second cell.

[0184] Optionally, the electronic device may determine the weight corresponding to each second cell based on the signal quality of each second cell in the one or more second cells by dividing the signal quality of any second cell in the one or more second cells by the maximum signal quality among the signal qualities of the one or more second cells to obtain the weight corresponding to the second cell. Of course, the electronic device may also determine the weight corresponding to each second cell in other ways based on the signal quality of each second cell in the one or more second cells, and this embodiment of the present application is not limited to this.

[0185] Step 306: The electronic device sends a measurement report message to the first cell.

[0186] The measurement report message includes the target signal strength of the second cell whose target signal strength among the one or more second cells is higher than the signal strength threshold. For example, the measurement report message may also include a cell identifier (including but not limited to PCI) of the second cell.

[0187] The signal strength threshold may be pre-set. For example, the signal strength threshold may be a threshold value of the B1 event included in the measurement configuration message.

[0188] It should be noted that after the electronic device receives the measurement configuration message, it can not only obtain the target signal strength of one or more second cells measured within the first preset time period every first preset time period, but also send a measurement report message to the first cell if there is a second cell in the one or more second cells whose target signal strength is higher than the signal strength threshold.

[0189] For example, if there is only one second cell among the one or more second cells whose target signal strength is higher than the signal strength threshold, the electronic device can send a measurement report message to the first cell. This measurement report message may include the target signal strength of the second cell, and may further include the cell identifier of the second cell, etc.

[0190] For example, if there are at least two second cells among the one or more second cells whose target signal strength is higher than the signal strength threshold, the electronic device may send a measurement report message to the first cell, and the measurement report message may include the target signal strength of each of the at least two second cells, and may further include the cell identifier of each of the at least two second cells, etc.; or, the electronic device may send at least two measurement report messages to the first cell, and each of the at least two measurement report messages may include the target signal strength of one of the at least two second cells, and may further include the cell identifier of the second cell, etc.; or, the electronic device may send at least one measurement report message to the first cell, and each of the at least one measurement report message may include the target signal strength of at least one of the at least two second cells, and may further include the cell identifier of each of the at least one second cell, etc.

[0191] After receiving the measurement report message sent by the electronic device, the first cell may select a second cell based on the target signal strength of the second cell included in the measurement report message sent by the electronic device, for example, the second cell with the highest target signal strength may be selected. The first cell may then instruct the electronic device to switch to the second cell.

[0192] Since the target signal strength of the second cell can reflect the comprehensive level of the actual signal strength and signal quality of the second cell, the second cell selected by the first cell based on the target signal strength of the second cell is a second cell with relatively good actual signal strength and signal quality overall.

[0193] Step 307: The first cell sends a handover command to the electronic device.

[0194] For example, the handover command may be an RRC connection reconfiguration message carrying a mobilityControlInfo information element.

[0195] Optionally, the handover command may include radio parameters required for handover to the second cell, such as a cell identifier of the second cell to be handed over, RB configuration information, etc.

[0196] Step 308: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0197] Optionally, the electronic device may access the second cell according to the wireless parameters included in the handover command.

[0198] For example, the electronic device may access the second cell using a random access method (including but not limited to a non-contention random access method) according to the wireless parameters included in the handover command.

[0199] Since the second cell has a relatively good actual signal strength and overall signal quality, the electronic device is likely to successfully access the second cell when attempting to access the cell.

[0200] If the electronic device successfully accesses the second cell, it can continue to perform other operations to complete the network fallback process. After the electronic device completes the network fallback process, it successfully falls back from the first network to the second network, and the electronic device can then make calls through the second network.

[0201] Next, a possible implementation manner of an electronic device accessing the second cell is exemplarily described with reference to FIG. 4 and FIG. 5 .

[0202] As an example, as shown in Figure 4, the communication system in the embodiment of the present application may include an electronic device, an access network, and a core network. The electronic device communicates with the access network, and the access network communicates with the core network.

[0203] The access network is responsible for connecting end users to the core network, using wired or wireless connections and communication technologies. The access network is the edge of the network, the part closest to users and is often called the "last mile."

[0204] For example, the access network of a 5G network includes a 5G cell, and the base station of the 5G cell (i.e., gNB) can be referred to as the access network device in the 5G network. For example, the access network of a 4G network includes a 4G cell, and the base station of the 4G cell (i.e., eNB) can be referred to as the access network device in the 4G network.

[0205] The core network's primary functions are to provide user connections, manage users, and carry services. As a bearer network, it provides an interface to external networks. Establishing user connections includes functions such as mobility management (MM), call management (CM), switching / routing, and recording notifications (combined with intelligent network services to establish connections to intelligent network peripheral devices).

[0206] For example, the core network of a 5G network is the 5G Core (abbreviated as 5GC). 5GC uses general-purpose network function virtualization equipment to replace the dedicated communication equipment of a 4G network. For example, the core network of a 4G network is the evolved packet core (EPC). The EPC has traditional mobile network capabilities such as user subscription data storage, mobility management, and data exchange, and can provide users with an ultra-high-speed Internet experience.

[0207] In this embodiment of the present application, a first cell belongs to an access network of a first network, and a base station of the first cell is an access network device in the first network. For example, assume that the first cell is a 5G cell. When an electronic device resides in a 5G cell, the electronic device communicates with the gNB of the 5G cell, and the gNB communicates with the 5GC.

[0208] The second cell belongs to the access network of the second network, and the base station of the second cell is an access network device in the second network. For example, assume that the second cell is a 4G cell. When the electronic device resides in the 4G cell, the electronic device communicates with the eNB of the 4G cell, and the eNB communicates with the EPC.

[0209] In some embodiments, the process of the electronic device accessing a second cell indicated by the handover command in step 308 involves interaction between the electronic device, an access network device of the second network (ie, a base station of the second cell), and a core network of the second network.

[0210] Assuming that in step 308, the electronic device accesses the second cell using a non-contention random access method, then in step 307, the handover command sent by the first cell to the electronic device may also include a non-contention random access preamble assigned to the electronic device. In this case, the handover command may also be referred to as an MSG0 message.

[0211] In this case, assuming that the second cell is a 4G cell, the process of the electronic device accessing a 4G cell indicated by the switching command in step 308 involves interaction between the electronic device, the eNB of the 4G cell, and the EPC, as described in detail in the embodiment of Figure 5 below.

[0212] FIG5 is a schematic diagram of a cell access process provided by an embodiment of the present application. Referring to FIG5 , the cell access process may include the following steps 501 to 508 .

[0213] Step 501: The electronic device sends a random access preamble to the eNB of the 4G cell.

[0214] For example, the electronic device may send the random access prefix assigned in the handover command to the eNB of the 4G cell according to the cell identifier of the 4G cell included in the handover command.

[0215] For example, the electronic device may carry the random access prefix in a MSG1 message and send it to the eNB.

[0216] Step 502: After receiving the random access prefix, the eNB sends a random access response message to the electronic device.

[0217] For example, the random access response message may also be called a MSG2 message.

[0218] It should be noted that after the electronic device receives the random access response message sent by the eNB, it has actually accessed the 4G cell. However, since the cell where the electronic device resides has changed, the electronic device needs to perform a TAU after accessing the 4G cell to notify the network side (i.e., the eNB and EPC) of its current TA. Therefore, after receiving the random access response message, the electronic device will also perform the following steps 503 to 508 to perform a TAU.

[0219] Step 503: After receiving the random access response message, the electronic device sends an RRC connection reconfiguration complete message to the eNB. The RRC connection reconfiguration complete message includes a TAU request message.

[0220] In some embodiments, after receiving the handover command, the electronic device may first configure the relevant RBs according to the RB configuration information in the handover command, for example, SRB1, SRB2, and DRB. In this case, in step 503, the electronic device may send the RRC connection reconfiguration complete message to the eNB via SRB1.

[0221] For example, the TAU request message may include the TAI of the TA in which the electronic device is currently located.

[0222] Step 504: After receiving the RRC connection reconfiguration complete message, the eNB sends an initial UE message to the EPC. The initial UE message includes a TAU request message.

[0223] Step 505: After receiving the initial UE message, the EPC sends a downlink NAS transport message to the eNB. The downlink NAS transport message includes a TAU acceptance message.

[0224] Optionally, after receiving the initial UE message, if the EPC determines that the electronic device is accessing for the first time, the EPC may perform authentication (authentication / security) on the electronic device to create some security-related parameters for the electronic device.

[0225] Optionally, after receiving the initial UE message, the EPC may update the TA or TA list of the electronic device, and after the update, send a downlink NAS transmission message including a TAU acceptance message to the eNB.

[0226] Step 506: After receiving the downlink NAS transfer message, the eNB sends a downlink information transfer (DL information transfer) message to the electronic device, where the downlink information transfer message includes a TAU acceptance message.

[0227] Step 507: After receiving the downlink information transfer message, the electronic device sends an uplink information transfer (UL information transfer) message to the eNB. The uplink information transfer message includes a TAU complete message of the NAS layer.

[0228] Optionally, the electronic device may send the uplink information transmission message to the eNB via SRB2.

[0229] Step 508: After receiving the uplink information transport message, the eNB sends an uplink NAS transport message to the EPC. The uplink NAS transport message includes a TAU completion message.

[0230] After the EPC receives the TAU completion message, the TAU process is completed.

[0231] At this point, the electronic device has completed the cell access process and the related TAU process. Afterwards, the electronic device can continue to perform other operations to complete the EPSFB process. After the electronic device completes the EPSFB process, it successfully falls back from the 5G network to the 4G network, and the electronic device can then make calls over the 4G network.

[0232] It should be noted that the embodiment of the present application only uses the embodiment of FIG. 5 above as an example to illustrate the process of the electronic device accessing the second cell in step 308, and the embodiment of FIG. 5 above does not limit the embodiment of the present application. The electronic device may also access the second cell in other ways different from the embodiment of FIG. 5 above, and the embodiment of the present application is not limited to this.

[0233] It should be noted that the embodiment of Figure 3 above is only an example of an example of a network fallback process triggered by a call scenario. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiment of the present application. That is to say, in the embodiment of the present application, when the electronic device accesses the first cell in step 301, not only can the network fallback process described in subsequent steps 303 to 308 be triggered in the scenario described in step 302, but the network fallback process described in subsequent steps 303 to 308 can also be triggered in other scenarios where there is a network fallback demand. The cell access method provided in the embodiment of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0234] In an embodiment of the present application, after receiving a measurement configuration message from a first cell, an electronic device can measure not only the actual signal strength of a second cell but also the signal quality of the second cell. Furthermore, at intervals of a first preset time interval, the actual signal strengths of the one or more second cells measured within the first preset time interval can be processed to obtain target signal strengths for the one or more second cells. The electronic device can send a measurement report message to the first cell, including the target signal strengths of the second cells whose target signal strengths exceed a signal strength threshold. Thereafter, the electronic device can receive a handover command from the first cell. Because the target signal strength of the second cell can reflect the combined level of the actual signal strength and signal quality of the second cell, after receiving the measurement report message from the electronic device, the first cell, through the handover command, indicates to the electronic device that the second cell to be handed over to has relatively good actual signal strength and signal quality overall. This increases the success rate of the electronic device in accessing this second cell, thereby improving the success rate of the network fallback process.

[0235] In one possible implementation, the cell access method provided in the embodiment of the present application is used to solve the problem in step 207 of the embodiment of Figure 2 above where the electronic device attempts to access 4G cell A but fails to do so. This is described in detail in the embodiment of Figure 6 below.

[0236] FIG6 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG6 , the method includes the following steps:

[0237] Step 601: An electronic device accesses a first cell.

[0238] The operation of step 601 is similar to the operation of step 301 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0239] Step 602: The electronic device sends an invite message to the first cell, or the first cell sends an invite message to the electronic device.

[0240] The operation of step 602 is similar to the operation of step 302 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0241] Whether the electronic device sends an invite message to the first cell or the first cell sends an invite message to the electronic device, since the electronic device does not support calls through the first network, a network fallback process will be triggered, that is, a process of falling back from the first network to the second network will be triggered so that the electronic device can make subsequent calls through the second network. In this embodiment of the present application, the network fallback process may include at least the following steps 603 to 607.

[0242] Step 603: The first cell sends a measurement configuration message to the electronic device.

[0243] The operation of step 603 is similar to the operation of step 303 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0244] Step 604: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0245] The operation of step 604 is similar to the operation of step 304 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0246] After measuring the signal strength and signal quality of a second cell, the electronic device may determine whether the signal strength of the second cell is higher than a signal strength threshold, and determine whether the signal quality of the second cell is lower than a signal quality threshold.

[0247] The signal quality threshold can be set in advance. If the signal quality of a second cell is not lower than the signal quality threshold, it means that the signal quality of the second cell is good; if the signal quality of a second cell is lower than the signal quality threshold, it means that the signal quality of the second cell is poor.

[0248] If the electronic device measures that the signal strength of a second cell is greater than a signal strength threshold, and the signal quality of the second cell is not less than a signal quality threshold, the electronic device reports the signal strength of the second cell to the first cell. That is, the electronic device sends a measurement report message including the signal strength of the second cell to the first cell. After receiving the measurement report message, the first cell may send a handover command to the electronic device. After receiving the handover command, the electronic device may access the second cell indicated by the handover command.

[0249] The operation of the first cell sending a handover command to the electronic device is similar to the operation of step 307 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0250] The operation of the electronic device accessing a second cell indicated by the handover command is similar to the operation of step 308 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0251] If the electronic device measures that the signal strength of a second cell is not higher than the signal strength threshold, the electronic device does not report the signal strength of the second cell to the first cell, that is, the electronic device does not send a measurement report message including the signal strength of the second cell to the first cell.

[0252] If the electronic device measures that the signal strength of a second cell is higher than the signal strength threshold, but the signal quality of the second cell is lower than the signal quality threshold, the electronic device does not report the signal strength of the second cell to the first cell, that is, the electronic device does not send a measurement report message including the signal strength of the second cell to the first cell.

[0253] That is, regardless of whether the signal strength of a second cell is higher than the signal strength threshold, as long as the signal quality of the second cell is lower than the signal quality threshold, the electronic device will not report the signal strength of the second cell to the first cell, that is, the electronic device will not send a measurement report message including the signal strength of the second cell to the first cell, as described in step 605 below.

[0254] Step 605: If the signal quality of the second cell is lower than the signal quality threshold, the electronic device does not send a measurement report message to the first cell.

[0255] If the signal quality of a second cell is lower than the signal quality threshold, it means that the signal quality of the second cell is relatively poor. In this case, the electronic device does not send a measurement report message including the signal strength of the second cell to the first cell.

[0256] It should be noted that if the electronic device receives the measurement configuration message and the measured signal quality of all second cells is lower than the signal quality threshold, then in the embodiment of the present application, the electronic device will not report the signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will not send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it times out and does not receive the measurement report message sent by the electronic device, it will send a redirection message to the first cell to trigger the electronic device to perform the redirection process.

[0257] Step 606: The first cell sends a redirection message to the electronic device.

[0258] The redirection message is used to instruct the electronic device to redirect to a neighboring cell of a different system. For example, the redirection message may be an RRC connection release message carrying a redirected frequency point (redirectedCarrierInfo) information element. The redirected frequency point information element may include a redirected frequency point.

[0259] Step 607: After receiving the redirection message, the electronic device accesses a second cell.

[0260] After receiving the redirection message, the electronic device will execute the redirection process. Specifically, the electronic device can release the RRC connection with the first cell. After the RRC connection is released, the electronic device is in the RRC idle state, and then the electronic device can access a second cell.

[0261] In some embodiments, after the electronic device releases the RRC connection with the first cell, it can first search for the second cell corresponding to the redirected frequency. If there is no suitable second cell on the redirected frequency, the electronic device can expand the search range, that is, it can search for second cells corresponding to other frequencies to search for a possible better second cell and then access it.

[0262] In an embodiment of the present application, after the electronic device receives the measurement configuration message sent by the first cell, if the measured signal quality of the second cell is relatively poor, the electronic device does not send a measurement report message to the first cell to trigger the first cell to instruct the electronic device to perform a redirection process. Since the electronic device can select a suitable second cell to access when executing the redirection process, the access success rate is relatively high. If the electronic device successfully accesses the second cell, it can continue to perform other operations to complete the network fallback process. After the electronic device completes the network fallback process, that is, it successfully falls back from the first network to the second network, then the electronic device can make calls through the second network.

[0263] In some embodiments, the operation of the electronic device accessing a second cell may include the following two methods:

[0264] The first way: the electronic device accesses a second cell whose signal strength is higher than the signal strength threshold and whose signal quality is not lower than the signal quality threshold.

[0265] Since the signal strength and signal quality of the second cell are relatively good, the success rate of the electronic device accessing the second cell is relatively high.

[0266] The second way: the electronic device accesses a second cell belonging to a preset cell type.

[0267] The preset cell type can be set in advance. The preset cell type is a cell type with a higher access success rate. Therefore, the electronic device has a higher success rate when accessing the second cell belonging to the preset cell type.

[0268] For example, the preset cell type can be a high-speed rail cell. Of course, the preset cell type can also be other cell types, and the embodiments of the present application do not limit this. Among them, the high-speed rail cells are some cells set up along the high-speed rail line, which are mainly used to solve the problem of poor signal of the electronic devices of people riding the high-speed rail during the high-speed rail journey. Since the high-speed rail cell is generally dedicated, it will not be too congested. In addition, some operators will isolate the high-speed rail cell and the non-high-speed rail cell, so it is not easy to have problems when accessing the high-pass cell. Therefore, during the high-speed rail journey, the electronic devices of people riding the high-speed rail have a relatively high success rate in accessing the high-speed rail cell, and the network experience after accessing the high-speed rail cell is also better.

[0269] Optionally, the system message broadcast by the second cell may carry the cell type of the second cell. In this case, the electronic device may parse the system message of the second cell to obtain the cell type of the second cell.

[0270] In some embodiments, in step 607, the electronic device may access a second cell using a random access method (including but not limited to a contention-based random access method).

[0271] It should be noted that after receiving the redirection message, the electronic device releases the RRC connection with the first cell. After the RRC connection is released, the electronic device enters the RRC idle state. After the electronic device enters the RRC idle state and searches for a suitable second cell, it resides in the second cell and attempts to access it. Since the cell where the electronic device resides has changed, the TAU process is triggered. During the TAU process, the electronic device accesses the second cell and performs a TAU.

[0272] Next, a possible implementation manner of an electronic device accessing the second cell is exemplarily described with reference to FIG. 7 .

[0273] Assuming that the second cell is a 4G cell, the process of the electronic device accessing a 4G cell in step 607 involves interaction between the electronic device, the eNB of the 4G cell, and the EPC, as described in detail in the embodiment of FIG. 7 below.

[0274] FIG7 is a schematic diagram of a cell access process provided by an embodiment of the present application. Referring to FIG7 , the cell access process may include the following steps 701 to 708 .

[0275] Step 701: The electronic device sends a random access prefix to the eNB of the 4G cell.

[0276] For example, the electronic device may carry the random access prefix in a MSG1 message and send it to the eNB.

[0277] Step 702: After receiving the random access prefix, the eNB sends a random access response message to the electronic device.

[0278] For example, the random access response message may also be called a MSG2 message.

[0279] Step 703: After receiving the random access response message, the electronic device sends an RRC connection request message to the eNB.

[0280] For example, the RRC connection request message may also be referred to as a MSG3 message.

[0281] Step 704: After receiving the RRC connection request message, the eNB sends an RRC connection establishment message to the electronic device.

[0282] For example, the RRC connection establishment message may also be referred to as a MSG4 message. The RRC connection establishment message may carry SRB1 configuration information.

[0283] It should be noted that after the electronic device receives the RRC connection establishment message sent by the eNB, it has actually connected to the 4G cell. However, since the cell where the electronic device resides has changed, the electronic device needs to perform a TAU after accessing the 4G cell to notify the network side (i.e., the eNB and EPC) of its current TA. Therefore, after receiving the RRC connection establishment message, the electronic device will also perform the following steps 705 to 710 to perform a TAU.

[0284] Step 705: After receiving the RRC connection establishment message, the electronic device sends an RRC connection establishment completion message to the eNB. The RRC connection establishment completion message includes a TAU request message.

[0285] After receiving the RRC connection establishment message, the electronic device may configure SRB1 according to the SRB1 configuration information in the RRC connection establishment message, and then may send the RRC connection establishment completion message to the eNB through SRB1.

[0286] For example, the TAU request message may include the TAI of the TA in which the electronic device is currently located.

[0287] Step 706: After receiving the RRC connection establishment complete message, the eNB sends an initial UE message to the EPC, where the initial UE message includes a TAU request message.

[0288] Step 707: After receiving the initial UE message, the EPC sends a downlink NAS transmission message to the eNB. The downlink NAS transmission message includes a TAU acceptance message.

[0289] Optionally, after receiving the initial UE message, if the EPC determines that the electronic device is accessing for the first time, the EPC may authenticate the electronic device to create some security-related parameters for the electronic device.

[0290] Optionally, after receiving the initial UE message, the EPC may update the TA or TA list of the electronic device, and after the update, send a downlink NAS transmission message including a TAU acceptance message to the eNB.

[0291] Step 708: After receiving the downlink NAS transmission message, the eNB sends a downlink information transmission message to the electronic device, where the downlink information transmission message includes a TAU acceptance message.

[0292] Step 709: After receiving the downlink information transmission message, the electronic device sends an uplink information transmission message to the eNB, where the uplink information transmission message includes a TAU completion message.

[0293] Since the electronic device triggers the TAU process in the RRC idle state, the electronic device can send the uplink information transmission message to the eNB through SRB1 in step 709.

[0294] Step 710: After receiving the uplink information transmission message, the eNB sends an uplink NAS transmission message to the EPC. The uplink NAS transmission message includes a TAU completion message.

[0295] After the EPC receives the TAU completion message, the TAU process is completed.

[0296] At this point, the electronic device has completed the cell access process and the related TAU process. Afterwards, the electronic device can continue to perform other operations to complete the EPSFB process. After the electronic device completes the EPSFB process, it successfully falls back from the 5G network to the 4G network, and the electronic device can then make calls over the 4G network.

[0297] It should be noted that the embodiment of the present application only uses the embodiment of FIG. 7 above as an example to exemplify the process of the electronic device accessing a second cell in step 607, and the embodiment of FIG. 7 above does not limit the embodiment of the present application. The electronic device may also access the second cell in other ways different from the embodiment of FIG. 7 above, and the embodiment of the present application is not limited to this.

[0298] It should be noted that the embodiment of Figure 6 above is only an example of an example of a network fallback process triggered by a call scenario. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiment of the present application. That is to say, in the embodiment of the present application, when the electronic device accesses the first cell in step 601, not only can the network fallback process described in subsequent steps 603 to 607 be triggered in the scenario described in step 602, but the network fallback process described in subsequent steps 603 to 607 can also be triggered in other scenarios where there is a network fallback demand. The cell access method provided in the embodiment of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0299] In an embodiment of the present application, after receiving a measurement configuration message sent by a first cell, the electronic device can measure not only the signal strength of the second cell, but also the signal quality of the second cell. If the signal quality of the second cell measured by the electronic device is lower than the signal quality threshold, the electronic device does not send a measurement report message to the first cell to trigger the first cell to instruct the electronic device to perform a redirection process. Because the electronic device can select a suitable second cell to access when performing the redirection process, the access success rate is relatively high, thereby improving the success rate of the network fallback process.

[0300] In one possible implementation, the cell access method provided in the embodiment of the present application is used to solve the problem in step 207 of the embodiment of Figure 2 above where the electronic device attempts to access 4G cell A but fails to do so. This is described in detail in the embodiment of Figure 8 below.

[0301] FIG8 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG8 , the method includes the following steps:

[0302] Step 801: An electronic device accesses a first cell.

[0303] The operation of step 801 is similar to the operation of step 301 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0304] Step 802: The electronic device sends an invite message to the first cell, or the first cell sends an invite message to the electronic device.

[0305] The operation of step 802 is similar to the operation of step 302 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0306] Whether the electronic device sends an invite message to the first cell or the first cell sends an invite message to the electronic device, since the electronic device does not support calls through the first network, a network fallback process will be triggered, that is, a process of falling back from the first network to the second network will be triggered so that the electronic device can make subsequent calls through the second network. In this embodiment of the present application, the network fallback process may include at least the following steps 803 to 809.

[0307] Step 803: The first cell sends a measurement configuration message to the electronic device.

[0308] The operation of step 803 is similar to the operation of step 303 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0309] Step 804: After receiving the measurement configuration message, the electronic device measures the signal strength of the second cell.

[0310] The operation of step 804 is similar to the operation of the electronic device measuring the signal strength of the second cell in step 304 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0311] Step 805: The electronic device determines whether there are multiple specific cells in the measured second cell; if the multiple specific cells exist in the measured second cell, step 806 is executed.

[0312] The multiple specific cells may be second cells having higher signal strengths and the same or similar signal strengths among the second cells measured by the electronic device. The signal strength of each of the multiple specific cells may be higher than a signal strength threshold, and a difference in signal strength between any two of the multiple specific cells may be less than a preset difference.

[0313] The preset difference value can be set in advance. The preset difference value can be set relatively small. If the difference in signal strength between the two second cells is less than the preset difference value, it indicates that the difference in signal strength between the two second cells is small; if the difference in signal strength between the two second cells is greater than or equal to the preset difference value, it indicates that the difference in signal strength between the two second cells is large.

[0314] It should be noted that if the multiple specific cells do not exist in the measured second cells, then for any measured second cell, the electronic device can report the signal strength of the second cell to the first cell if the signal strength of the second cell is higher than the signal strength threshold, that is, send a measurement report message including the signal strength of the second cell to the first cell.

[0315] If the measured second cells include the multiple specific cells, then for any second cell other than the multiple specific cells, the electronic device may report the signal strength of the second cell to the first cell if the signal strength of the second cell is greater than the signal strength threshold, i.e., send a measurement report message including the signal strength of the second cell to the first cell. For the multiple specific cells, it is necessary to first determine whether the electronic device is in a preset mobility state, and then determine whether to report the signal strengths of the multiple specific cells based on the determination, as described in step 806 below.

[0316] Step 806: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in the preset moving state, step 807 is executed.

[0317] The preset movement state can be set in advance. For example, the preset movement state can be a high-speed movement state.

[0318] Optionally, the operation of the electronic device determining whether the electronic device is in a preset moving state may be: determining that the electronic device is in the preset moving state when the moving speed of the electronic device is greater than or equal to a moving speed threshold; and determining that the electronic device is not in the preset moving state when the moving speed of the electronic device is less than the moving speed threshold.

[0319] The moving speed threshold can be pre-set. The moving speed threshold can be set to a larger value, such as 100 km / h (kilometers / hour), 150 km / h, 200 km / h, etc., which is not limited in the present embodiment.

[0320] It should be noted that if the electronic device is not in a preset mobile state, then for any specific cell among the multiple specific cells, the electronic device can report the signal strength of this specific cell to the first cell, that is, send a measurement report message including the signal strength of this specific cell to the first cell.

[0321] If the electronic device is in a preset moving state, the signal strength of the second cell measured by the electronic device will change relatively quickly. In this case, the signal strengths of the multiple specific cells are the same or similar, indicating that the electronic device is very likely to be moving to a relatively middle position of the multiple specific cells, but will soon move to other positions. In other words, although the signal strengths of the multiple specific cells are currently the same or similar, they will soon change. It is understandable that the signal strength of the specific cell located in front of the moving direction of the electronic device among the multiple specific cells will soon become stronger, while the signal strength of the specific cell located behind the moving direction of the electronic device will soon become weaker.

[0322] In this case, if the signal strengths of the multiple specific cells are directly reported to the first cell, then because the signal strengths of the multiple specific cells are the same or similar, the second cell selected by the first cell may be a second cell located behind the direction of movement of the electronic device. When the electronic device is in the preset moving state, the signal strength of this second cell will quickly weaken, and the electronic device may fail to access this second cell in subsequent attempts.

[0323] Therefore, in order to ensure the success rate of the subsequent electronic device accessing the second cell, the embodiment of the present application does not first report the signal strengths of the multiple specific cells to the first cell. Instead, the signal strengths of the multiple specific cells are remeasured after the second preset time period. Due to the passage of the second preset time period, the signal strengths of the multiple specific cells that previously had the same or similar signal strengths have changed, with the signal strengths of the specific cells located in front of the electronic device's moving direction becoming stronger, while the signal strengths of the specific cells located behind the electronic device's moving direction becoming weaker. This is described in detail in step 807 below.

[0324] Step 807: The electronic device re-measures the signal strengths of the multiple specific cells after a second preset time period.

[0325] The second preset duration can be pre-set. The second preset duration can be set to a smaller value, such as 1 second, 2 seconds, etc., which is not limited in the present embodiment. It should be noted that the first cell sets a timeout after sending the measurement configuration message, and the second preset duration is less than the timeout.

[0326] For any specific cell among the multiple specific cells, if the signal strength of this specific cell measured this time remains unchanged or decreases compared with the previous measurement, the signal strength of this specific cell will not be reported to the first cell, that is, the measurement report message including the signal strength of this specific cell will not be sent to the first cell.

[0327] If the signal strength of the specific cell measured this time is higher than that of the previous measurement, the signal strength of the specific cell measured this time is reported to the first cell, that is, a measurement report message including the signal strength of the specific cell is sent to the first cell, as described in step 808 below.

[0328] Step 808: The electronic device sends a measurement report message to the first cell.

[0329] The measurement report message includes the signal strength of the specific cell with increased signal strength among the multiple specific cells, and may further include a cell identifier (including but not limited to PCI) of the specific cell.

[0330] For example, if there is only one specific cell with increased signal strength among the multiple specific cells, the electronic device can send a measurement report message to the first cell. The measurement report message can include the signal strength of the specific cell and further include the cell identifier of the specific cell.

[0331] For example, if there are at least two specific cells with increased signal strength among the multiple specific cells, the electronic device can send a measurement report message to the first cell, and this measurement report message can include the signal strength of each specific cell among the at least two specific cells, and further can include the cell identifier of each specific cell among the at least two specific cells, etc.; or, the electronic device can send at least two measurement report messages to the first cell, and each measurement report message in the at least two measurement report messages can include the signal strength of one specific cell among the at least two specific cells, and further can include the cell identifier of this specific cell, etc.; or, the electronic device can send at least one measurement report message to the first cell, and each measurement report message in the at least one measurement report message can include the signal strength of at least one specific cell among the at least two specific cells, and further can include the cell identifier of each specific cell among the at least one specific cell, etc.

[0332] After receiving the measurement report message sent by the electronic device, the first cell may select a second cell based on the signal strength of the second cell included in the measurement report message sent by the electronic device, for example, the second cell with the highest signal strength. The first cell may then instruct the electronic device to switch to the second cell.

[0333] In an embodiment of the present application, when the electronic device is in a preset mobile state, if it discovers that there are multiple specific cells with high signal strength and the same or similar signal strength, it will delay reporting the signal strength of the specific cell with increased signal strength to the first cell until the signal strength of the multiple specific cells changes. Since the signal strength of the second cell located in front of the electronic device in the direction of movement increases with the movement of the electronic device compared to the second cell located behind the electronic device, the specific cell reported by the electronic device to the first cell is most likely the second cell located in front of the electronic device in the direction of movement. In this case, the second cell selected by the first cell based on the signal strength of the second cell reported by the electronic device is most likely a second cell located in front of the electronic device in the direction of movement.

[0334] Step 809: The first cell sends a handover command to the electronic device.

[0335] The operation of step 809 is similar to the operation of step 307 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0336] Step 810: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0337] The operation of step 810 is similar to the operation of step 308 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0338] Since the second cell indicated by the switching command is most likely located in front of the moving direction of the electronic device, the signal strength of the second cell will become stronger as the electronic device moves, so the electronic device will most likely successfully access the second cell when trying to access it.

[0339] If the electronic device successfully accesses the second cell, it can continue to perform other operations to complete the network fallback process. After the electronic device completes the network fallback process, it successfully falls back from the first network to the second network, and the electronic device can then make calls through the second network.

[0340] Optionally, a possible implementation manner for the electronic device to access the second cell may be the manner described in the embodiment of FIG. 5 above, which will not be described in detail in the embodiment of the present application.

[0341] It should be noted that the embodiment of Figure 8 above is only an example of an example of a network fallback process triggered by a call scenario. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiment of the present application. That is to say, in the embodiment of the present application, when the electronic device accesses the first cell in step 801, not only can the network fallback process described in subsequent steps 803 to 810 be triggered in the scenario described in step 802, but the network fallback process described in subsequent steps 803 to 810 can also be triggered in other scenarios where there is a network fallback demand. The cell access method provided in the embodiment of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0342] In an embodiment of the present application, after the electronic device receives the measurement configuration message sent by the first cell, it measures the signal strength of the second cell. If there are multiple specific cells with high signal strength and the same or similar signal strength in the measured second cell, then when the electronic device is in a preset mobile state, the signal strength of the multiple specific cells is remeasured after the second preset time length. After re-measuring the signal strength of the multiple specific cells, a measurement report message including the signal strength of the specific cell with increased signal strength is sent to the first cell. Afterwards, the electronic device can receive the handover command sent by the first cell. Since the second cell indicated by the handover command is most likely a second cell located in front of the moving direction of the electronic device, then as the electronic device moves, the signal strength of the second cell will become stronger and stronger, so the electronic device has a higher success rate in accessing the second cell, thereby improving the success rate of the network fallback process.

[0343] In some embodiments, the three possible methods provided in the embodiments of FIG. 3 to FIG. 8 above can be flexibly combined to better improve the success rate of the network fallback process.

[0344] Next, a possible combination of the embodiment of FIG. 3 and the embodiment of FIG. 6 is explained in detail.

[0345] FIG9 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG9 , the method includes the following steps:

[0346] Step 901: An electronic device accesses a first cell.

[0347] The operation of step 901 is similar to the operation of step 301 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0348] Step 902: The electronic device sends an invite message to the first cell, or the first cell sends an invite message to the electronic device.

[0349] The operation of step 902 is similar to the operation of step 302 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0350] Step 903: The first cell sends a measurement configuration message to the electronic device.

[0351] The operation of step 903 is similar to the operation of step 303 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0352] Step 904: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0353] The operation of step 904 is similar to the operation of step 304 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0354] Step 905: After receiving the measurement configuration message, the electronic device processes the signal strength of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time period at intervals of the first preset time period to obtain the target signal strength of the one or more second cells.

[0355] The operation of step 905 is similar to the operation of step 305 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0356] Step 906: For any second cell among the one or more second cells, the electronic device determines whether the target signal strength of the second cell is higher than a signal strength threshold and whether the signal quality of the second cell is not lower than a signal quality threshold.

[0357] If the target signal strength of the second cell is higher than the signal strength threshold and the signal quality of the second cell is not lower than the signal quality threshold, then steps 907 to 909 are performed. If the target signal strength of the second cell is not higher than the signal strength threshold and / or the signal quality of the second cell is lower than the signal quality threshold, then steps 910 to 912 are performed.

[0358] Step 907: If the target signal strength of the second cell is higher than the signal strength threshold and the signal quality of the second cell is not lower than the signal quality threshold, the electronic device sends a measurement report message including the target signal strength of the second cell to the first cell.

[0359] It should be noted that after the electronic device receives the measurement configuration message, it can not only obtain the target signal strength of one or more second cells measured within the first preset time period at intervals of the first preset time period, but also send a measurement report message to the first cell if there is a second cell in the one or more second cells whose target signal strength is higher than the signal strength threshold and whose signal quality is not lower than the signal quality threshold. For example, a measurement report message may include only the target signal strength of one second cell, and may further include the cell identifier of the second cell, etc.; or, a measurement report message may include the target signal strength of at least two second cells, and may further include the cell identifier of each of the at least two second cells, etc.

[0360] The operation of the electronic device sending the measurement report message to the first cell in step 907 is similar to the operation of the electronic device sending the measurement report message to the first cell in step 306 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0361] Step 908: The first cell sends a handover command to the electronic device.

[0362] The operation of step 908 is similar to the operation of step 307 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0363] Step 909: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0364] The operation of step 909 is similar to the operation of step 308 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0365] Step 910: If the target signal strength of the second cell is not higher than the signal strength threshold, and / or the signal quality of the second cell is lower than the signal quality threshold, the electronic device does not send a measurement report message including the target signal strength of the second cell to the first cell.

[0366] It should be noted that if the electronic device receives the measurement configuration message and the measured signal quality of all second cells is lower than the signal quality threshold, then in the embodiment of the present application, the electronic device will not report the target signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will not send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if the measurement report message sent by the electronic device is not received within a time limit, the first cell will send a redirection message to the first cell to trigger the electronic device to perform the redirection process.

[0367] The operation of the electronic device not sending a measurement report message to the first cell in step 910 is similar to the operation of the electronic device not sending a measurement report message to the first cell in step 605 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0368] Step 911: The first cell sends a redirection message to the electronic device.

[0369] The operation of step 911 is similar to the operation of step 606 in the embodiment of FIG. 6 above, and will not be described in detail in this embodiment of the present application.

[0370] Step 912: After receiving the redirection message, the electronic device accesses a second cell.

[0371] The operation of step 912 is similar to the operation of step 607 in the embodiment of FIG. 6 above, and will not be described in detail in this embodiment of the present application.

[0372] The technical effects obtained by the embodiment of FIG. 9 above are similar to the technical effects obtained by the corresponding technical means in the embodiment of FIG. 3 and the embodiment of FIG. 6 above, and will not be described in detail in the embodiment of the present application.

[0373] It should be noted that the embodiment of Figure 9 above is only an example of an example of a network fallback process triggered by a call scenario. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiment of the present application. That is to say, in the embodiment of the present application, when the electronic device accesses the first cell in step 901, not only can the network fallback process described in subsequent steps 903 to 912 be triggered in the scenario described in step 902, but the network fallback process described in subsequent steps 903 to 912 can also be triggered in other scenarios where there is a network fallback demand. The cell access method provided in the embodiment of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0374] Next, a possible combination of the embodiment of FIG. 3 and the embodiment of FIG. 8 is explained in detail.

[0375] FIG10 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG10 , the method includes the following steps:

[0376] Step 1001: An electronic device accesses a first cell.

[0377] The operation of step 1001 is similar to the operation of step 301 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0378] Step 1002: The electronic device sends an invite message to the first cell, or the first cell sends an invite message to the electronic device.

[0379] The operation of step 1002 is similar to the operation of step 302 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0380] Step 1003: The first cell sends a measurement configuration message to the electronic device.

[0381] The operation of step 1003 is similar to the operation of step 303 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0382] Step 1004: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0383] The operation of step 1004 is similar to the operation of step 304 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0384] Step 1005: After receiving the measurement configuration message, the electronic device processes the signal strength of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time period at intervals of the first preset time period to obtain the target signal strength of the one or more second cells.

[0385] The operation of step 1005 is similar to the operation of step 305 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0386] Step 1006 : The electronic device determines whether there are multiple specific cells in the one or more second cells; if there are multiple specific cells in the one or more second cells, step 1007 is executed.

[0387] The multiple specific cells are second cells having higher target signal strengths and the same or similar target signal strengths among the one or more second cells. That is, the target signal strength of each specific cell among the multiple specific cells is higher than the signal strength threshold, and the difference in target signal strengths between any two specific cells among the multiple specific cells is less than a preset difference.

[0388] It should be noted that if the multiple specific cells do not exist in the one or more second cells, then for any one of the one or more second cells, the electronic device can report the target signal strength of the second cell to the first cell if the target signal strength of the second cell is higher than the signal strength threshold, that is, send a measurement report message including the target signal strength of the second cell to the first cell.

[0389] If the multiple specific cells exist in the one or more second cells, then for any second cell other than the multiple specific cells in the one or more second cells, the electronic device may report the target signal strength of the second cell to the first cell if the target signal strength of the second cell is higher than the signal strength threshold, that is, send a measurement report message including the target signal strength of the second cell to the first cell. For the multiple specific cells, it is necessary to first determine whether the electronic device is in a preset mobile state, and then determine whether to report the target signal strengths of the multiple specific cells based on this, as described in step 1007 below.

[0390] Step 1007: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in the preset moving state, step 1008 is executed.

[0391] It should be noted that if the electronic device is not in the preset mobility state, then for any specific cell among the multiple specific cells, the electronic device may report the target signal strength of the specific cell to the first cell, i.e., send a measurement report message including the target signal strength of the specific cell to the first cell. If the electronic device is in the preset mobility state, step 1008 is executed.

[0392] Step 1008: The electronic device remeasures the signal strength and signal quality of the multiple specific cells after the second preset time period, and processes the signal strength of the multiple specific cells according to the measured signal quality of the multiple specific cells to obtain target signal strength of the multiple specific cells.

[0393] In step 1008, the electronic device processes the signal strength of the multiple specific cells according to the measured signal quality of the multiple specific cells to obtain the target signal strength of the multiple specific cells. This operation is similar to the operation in step 305 of the embodiment of Figure 3 above, in which the electronic device processes the signal strength of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time period to obtain the target signal strength of the one or more second cells. This embodiment of the present application will not be repeated here.

[0394] For any specific cell among the multiple specific cells, if the target signal strength of this specific cell measured this time remains unchanged or decreases compared with the previous measurement, the target signal strength of this specific cell will not be reported to the first cell, that is, the measurement report message including the target signal strength of this specific cell will not be sent to the first cell.

[0395] If the target signal strength of the specific cell measured this time is higher than that of the previous measurement, the target signal strength of the specific cell is reported to the first cell, that is, a measurement report message including the target signal strength of the specific cell is sent to the first cell, as described in step 1009 below.

[0396] Step 1009: The electronic device sends a measurement report message to the first cell.

[0397] The measurement report message includes the target signal strength of the specific cell with increased target signal strength among the multiple specific cells, and may further include a cell identifier (including but not limited to PCI) of the specific cell.

[0398] The operation of step 1009 is similar to the operation of step 808 in the embodiment of Figure 8 above, and will not be repeated in this embodiment of the present application.

[0399] Step 1010: The first cell sends a handover command to the electronic device.

[0400] The operation of step 1010 is similar to the operation of step 307 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0401] Step 1011: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0402] The operation of step 1011 is similar to the operation of step 308 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0403] The technical effects obtained by the embodiment of FIG10 above are similar to the technical effects obtained by the corresponding technical means in the embodiment of FIG3 and FIG8 above, and will not be described in detail in the embodiment of the present application.

[0404] It should be noted that the embodiment of Figure 10 above is only an example of an example of a network fallback process triggered by a call scenario. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiment of the present application. That is to say, in the embodiment of the present application, when the electronic device accesses the first cell in step 1001, it can not only trigger the network fallback process described in subsequent steps 1003 to 1011 in the scenario described in step 1002, but also trigger the network fallback process described in subsequent steps 1003 to 1011 in other scenarios where there is a network fallback demand. The cell access method provided in the embodiment of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0405] Next, a possible combination of the embodiment of FIG. 6 and the embodiment of FIG. 8 is explained in detail.

[0406] FIG11 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG11 , the method includes the following steps:

[0407] Step 1101: An electronic device accesses a first cell.

[0408] The operation of step 1101 is similar to the operation of step 601 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0409] Step 1102: The electronic device sends an invite message to the first cell, or the first cell sends an invite message to the electronic device.

[0410] The operation of step 1102 is similar to the operation of step 602 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0411] Step 1103: The first cell sends a measurement configuration message to the electronic device.

[0412] The operation of step 1103 is similar to the operation of step 603 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0413] Step 1104: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0414] The operation of step 1104 is similar to the operation of step 604 in the embodiment of FIG. 6 above, and will not be described in detail in this embodiment of the present application.

[0415] Step 1105: The electronic device determines whether there are multiple specific cells in the measured second cell; if the multiple specific cells exist in the measured second cell, step 1106 is executed.

[0416] The multiple specific cells are second cells having relatively high signal strengths and having the same or similar signal strengths among the second cells measured by the electronic device. That is, the signal strength of each specific cell in the multiple specific cells is higher than the signal strength threshold, and the difference in signal strength between any two specific cells in the multiple specific cells is less than a preset difference.

[0417] It should be noted that if the multiple specific cells do not exist in the measured second cells, then for any measured second cell, the electronic device may report the signal strength of the second cell to the first cell, i.e., send a measurement report message including the signal strength of the second cell to the first cell, if the signal strength of the second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold. If the signal strength of the second cell is not higher than the signal strength threshold and / or the signal quality of the second cell is lower than the signal quality threshold, the signal strength of the second cell will not be reported to the first cell, i.e., the measurement report message including the signal strength of the second cell will not be sent to the first cell.

[0418] If the multiple specific cells exist in the measured second cells, then for any second cells other than the multiple specific cells in the measured second cells, the electronic device may report the signal strength of the second cell to the first cell, i.e., send a measurement report message including the signal strength of the second cell to the first cell, if the signal strength of the second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold; and if the signal strength of the second cell is not higher than the signal strength threshold and / or the signal quality of the second cell is lower than the signal quality threshold, not report the signal strength of the second cell to the first cell, i.e., not send a measurement report message including the signal strength of the second cell to the first cell. For the multiple specific cells, it is necessary to first determine whether the electronic device is in a preset mobile state, and then determine whether to report the signal strengths of the multiple specific cells based on this, as described in step 1106 below.

[0419] Step 1106: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in the preset moving state, step 1107 is executed.

[0420] It should be noted that if the electronic device is not in a preset mobile state, then for any specific cell among the multiple specific cells, the electronic device can report the signal strength of this specific cell to the first cell if the signal quality of this specific cell is not lower than the signal quality threshold, that is, send a measurement report message including the signal strength of this specific cell to the first cell; if the signal quality of this specific cell is lower than the signal quality threshold, the electronic device will not report the signal strength of this specific cell to the first cell, that is, will not send a measurement report message including the signal strength of this specific cell to the first cell.

[0421] If the electronic device is in the preset moving state, the following step 1107 is executed.

[0422] Step 1107: The electronic device remeasures the signal strength and signal quality of the multiple specific cells after the second preset time period.

[0423] Step 1108: For any specific cell among the multiple specific cells, the electronic device determines whether the signal strength of the specific cell increases and whether the signal quality of the specific cell is not lower than the signal quality threshold.

[0424] If the signal strength of the specific cell increases and the signal quality of the specific cell is not lower than the signal quality threshold, then execute the following steps 1109 to 1111; if the signal strength of the specific cell remains unchanged or decreases, and / or the signal quality of the specific cell is lower than the signal quality threshold, then execute steps 1112 to 1114.

[0425] For any specific cell among the multiple specific cells, if the signal strength of this specific cell measured this time remains unchanged or decreases compared with the previous measurement, the signal strength of this specific cell will not be reported to the first cell, that is, the measurement report message including the signal strength of this specific cell will not be sent to the first cell, as described in the following step 1112.

[0426] If the signal strength of this specific cell measured this time is higher than that of the previous measurement, then the signal strength of this specific cell is reported to the first cell if the signal quality of this specific cell is not lower than the signal quality threshold, that is, a measurement report message including the signal strength of this specific cell is sent to the first cell, as described in the following step 1109; and if the signal quality of this specific cell is lower than the signal quality threshold, the signal strength of this specific cell is not reported to the first cell, that is, the measurement report message including the signal strength of this specific cell is not sent to the first cell, as described in the following step 1112.

[0427] Step 1109: If the signal strength of the specific cell increases and the signal quality of the specific cell is not lower than the signal quality threshold, the electronic device sends a measurement report message including the signal strength of the specific cell to the first cell.

[0428] The operation of the electronic device sending a measurement report message to the first cell in step 1109 is similar to the operation of the electronic device sending a measurement report message to the first cell in step 808 in the embodiment of Figure 8 above, and will not be repeated in this embodiment of the present application.

[0429] Step 1110: The first cell sends a handover command to the electronic device.

[0430] The operation of step 1110 is similar to the operation of step 809 in the embodiment of Figure 8 above, and will not be repeated in this embodiment of the present application.

[0431] Step 1111: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0432] The operation of step 1111 is similar to the operation of step 810 in the embodiment of Figure 8 above, and will not be repeated in this embodiment of the present application.

[0433] Step 1112: If the signal strength of the specific cell remains unchanged or decreases, and / or the signal quality of the specific cell is lower than the signal quality threshold, the electronic device does not send a measurement report message including the signal strength of the specific cell to the first cell.

[0434] It should be noted that if the electronic device receives the measurement configuration message and the measured signal quality of all second cells is lower than the signal quality threshold, then in the embodiment of the present application, the electronic device will not report the signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will not send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it times out and does not receive the measurement report message sent by the electronic device, it will send a redirection message to the first cell to trigger the electronic device to perform the redirection process.

[0435] The operation of the electronic device not sending a measurement report message to the first cell in step 1112 is similar to the operation of the electronic device not sending a measurement report message to the first cell in step 605 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0436] Step 1113: The first cell sends a redirection message to the electronic device.

[0437] The operation of step 1113 is similar to the operation of step 606 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0438] Step 1114: After receiving the redirection message, the electronic device accesses a second cell.

[0439] The operation of step 1114 is similar to the operation of step 607 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0440] The technical effects obtained by the embodiment of FIG11 above are similar to the technical effects obtained by the corresponding technical means in the embodiment of FIG6 and FIG8 above, and will not be described in detail in the embodiment of the present application.

[0441] It should be noted that the embodiment of Figure 11 above is only an example of an example of a network fallback process triggered by a call scenario. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiment of the present application. That is to say, in the embodiment of the present application, when the electronic device accesses the first cell in step 1101, it can not only trigger the network fallback process described in subsequent steps 1103 to 1114 in the scenario described in step 1102, but also trigger the network fallback process described in subsequent steps 1103 to 1114 in other scenarios where there is a network fallback demand. The cell access method provided in the embodiment of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0442] Next, a possible combination of the embodiment of FIG. 3 , the embodiment of FIG. 6 , and the embodiment of FIG. 8 will be explained in detail.

[0443] FIG12 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG12 , the method includes the following steps:

[0444] Step 1201: An electronic device accesses a first cell.

[0445] The operation of step 1201 is similar to the operation of step 301 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0446] Step 1202: The electronic device sends an invite message to the first cell, or the first cell sends an invite message to the electronic device.

[0447] The operation of step 1202 is similar to the operation of step 302 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0448] Step 1203: The first cell sends a measurement configuration message to the electronic device.

[0449] The operation of step 1203 is similar to the operation of step 303 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0450] Step 1204: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0451] The operation of step 1204 is similar to the operation of step 304 in the embodiment of FIG. 3 above, and will not be described in detail in this embodiment of the present application.

[0452] Step 1205: After receiving the measurement configuration message, the electronic device processes the signal strength of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time period at intervals of the first preset time period to obtain the target signal strength of the one or more second cells.

[0453] The operation of step 1205 is similar to the operation of step 305 in the embodiment of Figure 3 above, and will not be repeated in this embodiment of the present application.

[0454] Step 1206 : The electronic device determines whether there are multiple specific cells in the one or more second cells; if there are multiple specific cells in the one or more second cells, step 1207 is executed.

[0455] The multiple specific cells are second cells having higher target signal strengths and the same or similar target signal strengths among the one or more second cells. That is, the target signal strength of each specific cell among the multiple specific cells is higher than the signal strength threshold, and the difference in target signal strengths between any two specific cells among the multiple specific cells is less than a preset difference.

[0456] It should be noted that if the multiple specific cells do not exist in the one or more second cells, then for any one of the one or more second cells, the electronic device can report the target signal strength of the second cell to the first cell if the target signal strength of the second cell is higher than the signal strength threshold and the signal quality of the second cell is not lower than the signal quality threshold, that is, send a measurement report message including the target signal strength of the second cell to the first cell; if the target signal strength of the second cell is not higher than the signal strength threshold, and / or the signal quality of the second cell is lower than the signal quality threshold, the target signal strength of the second cell will not be reported to the first cell, that is, the measurement report message including the target signal strength of the second cell will not be sent to the first cell.

[0457] If the multiple specific cells exist in the one or more second cells, then for any other second cell in the one or more second cells except the multiple specific cells, the electronic device may report the target signal strength of the second cell to the first cell, i.e., send a measurement report message including the target signal strength of the second cell to the first cell, if the target signal strength of the second cell is higher than the signal strength threshold and the signal quality of the second cell is not lower than the signal quality threshold; and if the target signal strength of the second cell is not higher than the signal strength threshold and / or the signal quality of the second cell is lower than the signal quality threshold, not report the target signal strength of the second cell to the first cell, i.e., not send a measurement report message including the target signal strength of the second cell to the first cell. For the multiple specific cells, it is necessary to first determine whether the electronic device is in a preset mobile state, and then determine whether to report the target signal strengths of the multiple specific cells accordingly, as described in step 1207 below.

[0458] Step 1207: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in the preset moving state, step 1208 is executed.

[0459] It should be noted that if the electronic device is not in a preset mobile state, then for any specific cell among the multiple specific cells, the electronic device may report the target signal strength of the specific cell to the first cell if the signal quality of the specific cell is not lower than the signal quality threshold, that is, send a measurement report message including the target signal strength of the specific cell to the first cell; if the signal quality of the specific cell is lower than the signal quality threshold, the electronic device will not report the target signal strength of the specific cell to the first cell, that is, will not send a measurement report message including the target signal strength of the specific cell to the first cell. If the electronic device is in a preset mobile state, the following step 1208 is executed.

[0460] Step 1208: The electronic device remeasures the signal strength and signal quality of the multiple specific cells after the second preset time period, and processes the signal strength of the multiple specific cells according to the measured signal quality of the multiple specific cells to obtain target signal strength of the multiple specific cells.

[0461] In step 1208, the electronic device processes the signal strength of the multiple specific cells according to the measured signal quality of the multiple specific cells to obtain the target signal strength of the multiple specific cells. This operation is similar to the operation in step 305 of the embodiment of Figure 3 above, in which the electronic device processes the signal strength of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time period to obtain the target signal strength of the one or more second cells. The embodiments of the present application will not repeat this.

[0462] Step 1209: For any specific cell among the multiple specific cells, the electronic device determines whether the target signal strength of the specific cell increases and whether the signal quality of the specific cell is not lower than the signal quality threshold.

[0463] If the target signal strength of the specific cell increases and the signal quality of the specific cell is not lower than the signal quality threshold, then execute steps 1210 to 1212; if the target signal strength of the specific cell remains unchanged or decreases, and / or the signal quality of the specific cell is lower than the signal quality threshold, then execute steps 1213 to 1215.

[0464] For any specific cell among the multiple specific cells, if the target signal strength of this specific cell measured this time remains unchanged or decreases compared with the previous measurement, the target signal strength of this specific cell will not be reported to the first cell, that is, the measurement report message including the target signal strength of this specific cell will not be sent to the first cell, as described in step 1213 below.

[0465] If the target signal strength of this specific cell measured this time is higher than that of the previous measurement, then the target signal strength of this specific cell is reported to the first cell if the signal quality of this specific cell is not lower than the signal quality threshold, that is, a measurement report message including the target signal strength of this specific cell is sent to the first cell, as described in the following step 1210; and if the signal quality of this specific cell is lower than the signal quality threshold, the target signal strength of this specific cell is not reported to the first cell, that is, the measurement report message including the target signal strength of this specific cell is not sent to the first cell, as described in the following step 1213.

[0466] Step 1210: If the target signal strength of the specific cell increases and the signal quality of the specific cell is not lower than the signal quality threshold, the electronic device sends a measurement report message including the target signal strength of the specific cell to the first cell.

[0467] The operation of the electronic device sending a measurement report message to the first cell in step 1210 is similar to the operation of the electronic device sending a measurement report message to the first cell in step 808 in the embodiment of Figure 8 above, and will not be repeated in this embodiment of the present application.

[0468] Step 1211: The first cell sends a handover command to the electronic device.

[0469] The operation of step 1211 is similar to the operation of step 809 in the embodiment of Figure 8 above, and will not be repeated in this embodiment of the present application.

[0470] Step 1212: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0471] The operation of step 1212 is similar to the operation of step 810 in the embodiment of Figure 8 above, and will not be repeated in this embodiment of the present application.

[0472] Step 1213: If the target signal strength of the specific cell remains unchanged or decreases, and / or the signal quality of the specific cell is lower than the signal quality threshold, the electronic device does not send a measurement report message including the target signal strength of the specific cell to the first cell.

[0473] It should be noted that if the electronic device receives the measurement configuration message and the measured signal quality of all second cells is lower than the signal quality threshold, then in the embodiment of the present application, the electronic device will not report the target signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will not send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if the measurement report message sent by the electronic device is not received within a time limit, the first cell will send a redirection message to the first cell to trigger the electronic device to perform the redirection process.

[0474] The operation of the electronic device not sending a measurement report message to the first cell in step 1213 is similar to the operation of the electronic device not sending a measurement report message to the first cell in step 605 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0475] Step 1214: The first cell sends a redirection message to the electronic device.

[0476] The operation of step 1214 is similar to the operation of step 606 in the embodiment of FIG. 6 above, and will not be described in detail in this embodiment of the present application.

[0477] Step 1215: After receiving the redirection message, the electronic device accesses a second cell.

[0478] The operation of step 1215 is similar to the operation of step 607 in the embodiment of Figure 6 above, and will not be repeated in this embodiment of the present application.

[0479] The technical effects obtained by the embodiment of FIG12 above are similar to the technical effects obtained by the corresponding technical means in the embodiments of FIG3 , FIG6 and FIG8 above, and will not be described in detail in the embodiments of the present application.

[0480] It should be noted that the embodiment of Figure 12 above is only an example of an example of a network fallback process triggered by a call scenario. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiment of the present application. That is to say, in the embodiment of the present application, when the electronic device accesses the first cell in step 1201, it can not only trigger the network fallback process described in subsequent steps 1203 to 1215 in the scenario described in step 1202, but also trigger the network fallback process described in subsequent steps 1203 to 1215 in other scenarios where there is a network fallback demand. The cell access method provided in the embodiment of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0481] In one possible implementation, the cell access method provided in the embodiments of the present application is used to resolve the issue of the electronic device waiting for an excessively long time after sending an RRC connection reestablishment completion message to 4G cell B in step 211 of the embodiment of FIG. This is described in detail below in the embodiments of FIG. 13 and FIG. 14.

[0482] It should be noted that the embodiment of Figure 13 or Figure 14 can be executed when the electronic device triggers the RLF procedure. For example, in the embodiment of Figure 2 above, the electronic device can execute the embodiment of Figure 13 or Figure 14 below when the RLF procedure is triggered in step 208. Alternatively, in the embodiment of Figure 3 above, the electronic device can trigger the RLF procedure when it fails to access a second cell in step 308, and then execute the embodiment of Figure 13 or Figure 14 below. Alternatively, in the embodiment of Figure 6 above, the electronic device can trigger the RLF procedure when it fails to access a second cell in step 607, and then execute the embodiment of Figure 13 or Figure 14 below. Alternatively, in the embodiment of Figure 8 above, the electronic device can trigger the RLF procedure when it fails to access a second cell in step 809, and then execute the embodiment of Figure 13 or Figure 14 below. Similarly, in the embodiment of Figure 9 above, the electronic device can trigger the RLF procedure when it fails to access a second cell in steps 909 or 912, and then execute the embodiment of Figure 13 or Figure 14 below. Alternatively, in the embodiment of Figure 10 above, the electronic device may trigger an RLF process when it fails to access a second cell in step 1011, and then the embodiment of Figure 13 or Figure 14 below may be executed. Alternatively, in the embodiment of Figure 11 above, the electronic device may trigger an RLF process when it fails to access a second cell in step 1111 or step 1114, and then the embodiment of Figure 13 or Figure 14 below may be executed. Alternatively, in the embodiment of Figure 12 above, the electronic device may trigger an RLF process when it fails to access a second cell in step 1212 or step 1215, and then the embodiment of Figure 13 or Figure 14 below may be executed. Of course, the electronic device may also trigger an RLF process in other circumstances, and then execute the embodiment of Figure 13 or Figure 14 below.

[0483] FIG13 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG13 , the method includes the following steps:

[0484] Step 1301: The electronic device triggers the RLF process.

[0485] The RLF process involves a cell selection process and an RRC connection reestablishment process, which aims to reestablish the RRC connection. After triggering the RLF process, the electronic device may first select a cell (hereinafter referred to as a target cell), then camp on the target cell and establish an RRC connection with the target cell to access the target cell, as described in steps 1302 to 1306 below.

[0486] For example, after receiving a handover command sent by a first cell, the electronic device may trigger an RLF process when accessing a second cell indicated by the handover command fails. In this case, the target cell is the second cell.

[0487] Step 1302: The electronic device sends an RRC connection reestablishment request message to the target cell.

[0488] Optionally, the RRC connection reestablishment request message may carry a reestablishment reason. For example, the reestablishment reason triggered by RLF may be "otherFailure".

[0489] Step 1303: After receiving the RRC connection reestablishment request message, the target cell sends an RRC connection reestablishment message to the electronic device. The RRC connection reestablishment message carries SRB1 configuration information.

[0490] Step 1304: After receiving the RRC connection reestablishment message, the electronic device configures SRB1 according to the SRB1 configuration information.

[0491] Step 1305: The electronic device sends an RRC connection reestablishment completion message to the target cell.

[0492] For example, the electronic device may send an RRC connection reestablishment completion message to the target cell via SRB1.

[0493] After the electronic device sends the RRC connection reestablishment completion message to the target cell, the electronic device has established an RRC connection with the target cell, and at this time the electronic device is in an RRC connected state.

[0494] In this case, the electronic device has actually connected to the target cell. However, since the cell where the electronic device resides has changed, the electronic device still needs to perform a TAU after connecting to the target cell. Generally, when the electronic device is in the RRC connected state, it needs to perform a TAU via SRB2. Therefore, after the electronic device sends an RRC connection reestablishment complete message to the target cell, it needs to wait for the target cell to send an RRC reconfiguration message to configure SRB2 and DRB, and then perform a TAU via SRB2.

[0495] In the related art, after sending an RRC connection reestablishment completion message to a target cell, the electronic device can only wait for an RRC reconfiguration message for configuring SRB2 sent by the target cell.

[0496] In an embodiment of the present application, in order to prevent the electronic device from waiting too long after sending the RRC connection reestablishment complete message to the target cell, thereby causing a TAU failure and subsequently causing the failure of related network fallback processes, the electronic device sets a timer after sending the RRC connection reestablishment complete message to the target cell. The duration of the timer can be set in advance. In the embodiment of the present application, the duration of the timer is referred to as a third preset duration.

[0497] If the electronic device receives an RRC reconfiguration message from the target cell within the third preset duration after sending the RRC connection reestablishment complete message to the target cell before the timer expires, the electronic device can configure SRB2 according to the SRB2 configuration information in the RRC reconfiguration message and then perform a TAU over SRB2. At this point, the TAU can proceed normally, and its related network fallback processes, etc., can also continue normally.

[0498] However, if the electronic device expires the timer, that is, the electronic device still does not receive the RRC reconfiguration message sent by the target cell after the third preset time after sending the RRC connection reestablishment completion message to the target cell, the electronic device can perform TAU through SRB1, as described below.

[0499] Step 1306: If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the target cell after sending the RRC connection reestablishment completion message to the target cell for the third preset time, TAU is performed through SRB1.

[0500] The third preset duration can be set in advance. Optionally, the setting of the third preset duration can be based on the following principle: when the third preset duration times out, even if the RRC reconfiguration message for configuring SRB2 sent by the network side is not received, the electronic device will not receive the RRC connection release message sent by the network side. For example, the third preset duration can be less than the aforementioned 5 seconds (that is, 5 seconds that will result in the receipt of the RRC connection release message sent by the network side), specifically 2 seconds, or 3 seconds, etc., which is not limited in this embodiment of the present application.

[0501] In some embodiments, different user scenarios may correspond to different third preset durations. The user scenario refers to the user's usage scenario, that is, what the user is doing with the electronic device. The user scenario may reflect user needs.

[0502] In this case, the third preset duration corresponding to user scenarios with higher network latency requirements can be relatively short. The third preset duration corresponding to user scenarios with lower network latency requirements can be relatively long. For example, if the user scenario of the electronic device is a call scenario, the third preset duration can be relatively short, such as 2 seconds or 3 seconds. If the user scenario of the electronic device is a web browsing scenario, the third preset duration can be relatively long, such as 7 seconds or 8 seconds.

[0503] In an embodiment of the present application, after the electronic device sends an RRC connection reestablishment completion message to the target cell, if the electronic device still does not receive the RRC reconfiguration message sent by the target cell after a third preset time period, the electronic device can directly perform TAU through SRB1 when the electronic device is currently in an RRC connected state (as opposed to some existing technologies in which TAU can only be performed through SRB2 when the electronic device is currently in an RRC connected state). This ensures the normal progress of the TAU, thereby improving the success rate of related network fallback processes, etc.

[0504] Next, a possible implementation manner of TAU by an electronic device through SRB1 is exemplarily described with reference to FIG14 .

[0505] Assuming that the target cell is a 4G cell, the process of the electronic device performing TAU through SRB1 involves interaction between the electronic device, the eNB of the 4G cell, and the EPC, as described in detail in the embodiment of Figure 14 below.

[0506] FIG14 is a schematic diagram of a TAU process provided by an embodiment of the present application. Referring to FIG14 , the TAU process may include the following steps 1401 to 1406 .

[0507] Step 1401: The electronic device sends an uplink information transmission message to the eNB of the 4G cell via SRB1, where the uplink information transmission message includes a TAU request message.

[0508] Step 1402: After receiving the uplink information transmission message, the eNB sends an uplink NAS transmission message to the EPC. The uplink NAS transmission message includes a TAU request message.

[0509] Step 1403: After receiving the uplink NAS transmission message, the EPC sends a downlink NAS transmission message to the eNB. The downlink NAS transmission message includes a TAU acceptance message.

[0510] Optionally, after receiving the uplink NAS transmission message, the EPC may update the TA or TA list of the electronic device, and after the update, send a downlink NAS transmission message including a TAU acceptance message to the eNB.

[0511] Step 1404: After receiving the downlink NAS transmission message, the eNB sends a downlink information transmission message to the electronic device, where the downlink information transmission message includes a TAU acceptance message.

[0512] Step 1405: After receiving the downlink information transmission message, the electronic device sends an uplink information transmission message to the eNB via SRB1. The uplink information transmission message includes a TAU completion message.

[0513] Step 1406: After receiving the uplink information transmission message, the eNB sends an uplink NAS transmission message to the EPC. The uplink NAS transmission message includes a TAU completion message.

[0514] After the EPC receives the TAU completion message, the TAU process is completed.

[0515] In some cases, if the electronic device is performing the TAU process during the EPSFB process, the electronic device can continue to perform other operations to complete the EPSFB process after completing the TAU process. After the electronic device completes the EPSFB process, it successfully falls back from the 5G network to the 4G network.

[0516] It should be noted that the present embodiment of the present application only uses the embodiment of FIG. 14 above as an example to illustrate the process of the electronic device performing TAU via SRB1 in step 1306. The embodiment of FIG. 14 above does not limit the present embodiment of the present application. The electronic device may also perform TAU via SRB1 in other ways different from the embodiment of FIG. 14 above, and the present embodiment of the present application is not limited thereto.

[0517] In some embodiments, if the electronic device receives an RRC reconfiguration message sent by the target cell within a third preset time period after sending an RRC connection reestablishment complete message to the target cell, the electronic device may configure SRB2 according to the SRB2 configuration information in the RRC reconfiguration message, and then perform a TAU via SRB2. As an example, the process of the electronic device performing a TAU via SRB2 is similar to the embodiment of FIG. 14 above, with the only difference being that in both steps 1401 and 1405, the electronic device sends an uplink information transmission message to the eNB via SRB2.

[0518] In an embodiment of the present application, if the electronic device triggers the RLF process, it sends an RRC connection reestablishment request message to the target cell. Afterwards, if the electronic device receives the RRC connection reestablishment message sent by the target cell, it configures SRB1 according to the SRB1 configuration information in the RRC connection reestablishment message, and sends an RRC connection reestablishment completion message to the target cell. After the electronic device sends the RRC connection reestablishment completion message to the target cell, if it still does not receive the RRC reconfiguration message for configuring SRB2 sent by the target cell after a third preset time period, TAU is performed through SRB1. This can ensure the normal progress of TAU, and then improve the success rate of related network fallback processes, etc.

[0519] FIG15 is a flow chart of a cell access method provided in an embodiment of the present application. Referring to FIG15 , the method includes the following steps:

[0520] Step 1501: The electronic device triggers the RLF process.

[0521] The RLF process involves a cell selection process and an RRC connection reestablishment process, the purpose of which is to reestablish the RRC connection. After triggering the RLF process, the electronic device may first select a cell (hereinafter referred to as a first target cell), then reside in the first target cell and establish an RRC connection with the first target cell to access the first target cell, as described in steps 1502 to 1506 below.

[0522] For example, after receiving a handover command sent by a first cell, the electronic device may trigger an RLF process when accessing a second cell indicated by the handover command fails. In this case, the first target cell is the second cell.

[0523] Step 1502: The electronic device sends an RRC connection reestablishment request message to the first target cell.

[0524] Optionally, the RRC connection reestablishment request message may carry a reestablishment reason. For example, the reestablishment reason triggered by RLF may be "otherFailure".

[0525] Step 1503: After receiving the RRC connection reestablishment request message, the first target cell sends an RRC connection reestablishment message to the electronic device.

[0526] Illustratively, the RRC connection reestablishment message carries SRB1 configuration information.

[0527] Step 1504: After receiving the RRC connection reestablishment message, the electronic device sends an RRC connection reestablishment completion message to the first target cell.

[0528] For example, after receiving the RRC connection reestablishment message, the electronic device may configure SRB1 according to the SRB1 configuration information, and then send an RRC connection reestablishment complete message to the first target cell through SRB1.

[0529] After the electronic device sends the RRC connection reestablishment completion message to the first target cell, the electronic device has reestablished the RRC connection with the first target cell, and the electronic device is now in an RRC connected state.

[0530] In this case, the electronic device has actually connected to the first target cell. However, since the cell where the electronic device resides has changed, the electronic device still needs to perform a TAU after connecting to the first target cell. Generally, when the electronic device is in the RRC connected state, it needs to perform a TAU via SRB2. Therefore, after the electronic device sends an RRC connection reestablishment complete message to the first target cell, it needs to wait for the RRC reconfiguration message sent by the first target cell to configure SRB2 and DRB, and then perform a TAU via SRB2.

[0531] In the related art, after sending an RRC connection reestablishment completion message to the first target cell, the electronic device can only wait for an RRC reconfiguration message for configuring SRB2 sent by the first target cell.

[0532] In an embodiment of the present application, in order to prevent the electronic device from waiting too long after sending the RRC connection reestablishment completion message to the first target cell, thereby causing the RRC connection reestablishment process to fail, and subsequently causing the failure of related network fallback processes, etc., the electronic device will set a timer after sending the RRC connection reestablishment completion message to the first target cell. The duration of the timer can be set in advance. In the embodiment of the present application, the duration of the timer is referred to as a fourth preset duration.

[0533] If the electronic device receives an RRC reconfiguration message sent by the first target cell within the fourth preset duration after the timer expires, that is, after sending the RRC connection reestablishment complete message to the first target cell, the electronic device may configure SRB2 according to the SRB2 configuration information in the RRC reconfiguration message and then perform a TAU via SRB2. At this point, the TAU can proceed normally, and its related network fallback processes, etc., can also continue normally.

[0534] However, if the electronic device expires when the timer times out, that is, the electronic device still does not receive the RRC reconfiguration message sent by the first target cell after the fourth preset time after sending the RRC connection reestablishment completion message to the first target cell, the electronic device can trigger the RLF process to trigger the cell change reestablishment, as described below.

[0535] Step 1505: If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the first target cell after the fourth preset time period of sending the RRC connection reestablishment completion message to the first target cell, the RLF process is triggered.

[0536] The fourth preset duration can be set in advance. Optionally, the setting of the fourth preset duration can be based on the following principle: when the fourth preset duration times out, even if the RRC reconfiguration message for configuring SRB2 sent by the network side is not received, the electronic device will not receive the RRC connection release message sent by the network side. For example, the fourth preset duration can be less than the aforementioned 5 seconds (that is, 5 seconds that will result in the receipt of the RRC connection release message sent by the network side), specifically 2 seconds, or 3 seconds, etc., which is not limited in this embodiment of the present application.

[0537] In some embodiments, different user scenarios may correspond to different fourth preset durations. The user scenario refers to the user's usage scenario, that is, what the user is doing with the electronic device. The user scenario may reflect user needs.

[0538] In this case, the fourth preset duration corresponding to user scenarios with higher network latency requirements may be relatively short. The fourth preset duration corresponding to user scenarios with lower network latency requirements may be relatively long. For example, if the user scenario of the electronic device is a call scenario, the fourth preset duration may be relatively short, such as 1 second or 2 seconds. If the user scenario of the electronic device is a web browsing scenario, the fourth preset duration may be relatively long, such as 5 seconds or 6 seconds.

[0539] After the electronic device sends the RRC connection reestablishment completion message to the first target cell, if the fourth preset time period has expired and the RRC reconfiguration message sent by the first target cell is still not received, then the RRC connection reestablishment process between the electronic device and the first target cell is likely to fail. In this case, in an embodiment of the present application, the electronic device can directly trigger the RLF process to trigger the cell change reestablishment. In this way, the cell can be changed as soon as possible to perform the RRC connection reestablishment process, avoiding the electronic device from waiting for a long time and meaninglessly, thereby improving the success rate of related network fallback processes, etc.

[0540] Step 1506: The electronic device performs an RRC connection reestablishment process with the second target cell.

[0541] After triggering the RLF process, the electronic device can first release the RRC connection with the first target cell, and then select a cell (i.e., the second target cell). After that, the electronic device can first reside in the second target cell, and then establish an RRC connection with the second target cell to access the second target cell.

[0542] In some embodiments, after the electronic device receives a handover command sent by the first cell, an RLF process may be triggered when access to a second cell indicated by the handover command fails, and then a second cell may be selected as the first target cell to perform an RRC connection reestablishment process with the first target cell. During the RRC connection reestablishment process with the first target cell, if the electronic device does not receive an RRC reconfiguration message for configuring SRB2 sent by the first target cell after sending an RRC connection reestablishment completion message to the first target cell for a fourth preset time period, the RLF process is triggered, and then a second cell may continue to be selected as the second target cell, and the RRC connection reestablishment process may be performed with the second target cell.

[0543] Among them, the process of the electronic device performing the RRC connection reestablishment process with the second target cell is similar to the process of the electronic device performing the RRC connection reestablishment process with the first target cell, and the embodiment of the present application will not be repeated here.

[0544] In some embodiments, during the RRC connection reconstruction process between the electronic device and the second target cell, if the electronic device does not receive the RRC reconfiguration message sent by the second target cell for configuring SRB2 after the fourth preset time length of sending the RRC connection reconstruction completion message to the second target cell, the RLF process can be triggered to continue selecting a cell to perform the RRC connection reconstruction process.

[0545] In an embodiment of the present application, if the electronic device triggers the RLF process, it sends an RRC connection reestablishment request message to the first target cell. Afterwards, if the electronic device receives the RRC connection reestablishment message sent by the first target cell, it sends an RRC connection reestablishment completion message to the first target cell. After the electronic device sends the RRC connection reestablishment completion message to the first target cell, if it still does not receive the RRC reconfiguration message for configuring SRB2 sent by the first target cell after the fourth preset time period, the electronic device will no longer continue to wait for the first target cell to send the RRC reconfiguration message, but will directly trigger the RLF process to change the cell as soon as possible to perform the RRC connection reestablishment process. In this way, the long and meaningless waiting of the electronic device in the RRC connection reestablishment process can be avoided, and the success rate of related network fallback processes, etc. can be improved.

[0546] The electronic device involved in the embodiments of the present application is described below.

[0547] FIG16 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Referring to FIG16 , the electronic device 100 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone jack 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display 194, and a subscriber identification module (SIM) card interface 195, etc. Among them, the sensor module 180 can include a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0548] It should be understood that the structures illustrated in the embodiments of the present application do not constitute a specific limitation on the electronic device 100. In other embodiments of the present application, the electronic device 100 may include more or fewer components than shown, or may combine or separate certain components, or arrange the components differently. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0549] The processor 110 may include one or more processing units, for example, an application processor (AP), a modem (also known as a baseband processor), a graphics processing unit (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), and / or a neural-network processing unit (NPU). The different processing units may be independent devices or integrated into one or more processors.

[0550] The controller may be the nerve center and command center of the electronic device 100. The controller may generate an operation control signal according to the instruction operation code and the timing signal to complete the control of fetching and executing instructions.

[0551] Processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in processor 110 is a cache memory. This memory can store instructions or data that have just been used or are being recycled by processor 110. If processor 110 needs to use the instruction or data again, it can directly access the memory. This avoids duplicate accesses, reduces processor 110 latency, and thus improves system efficiency.

[0552] The wireless communication function of the electronic device 100 can be implemented through the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem, etc.

[0553] Antenna 1 and Antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in electronic device 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve antenna utilization. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In other embodiments, the antennas can be used in conjunction with a tuning switch.

[0554] The mobile communication module 150 can provide solutions for wireless communications including 2G / 3G / 4G / 5G applied to the electronic device 100. The mobile communication module 150 may include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves from the antenna 1, and filter, amplify, and process the received electromagnetic waves, and transmit them to the modulation and demodulation processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modulation and demodulation processor, and convert it into electromagnetic waves for radiation through the antenna 1. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the processor 110. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the same device as at least some of the modules of the processor 110.

[0555] The wireless communication module 160 can provide wireless communication solutions including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), etc., which are applied to the electronic device 100. The wireless communication module 160 can be one or more devices that integrate at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, frequency modulates and filters the electromagnetic wave signals, and sends the processed signals to the processor 110. The wireless communication module 160 can also receive the signal to be sent from the processor 110, frequency modulate it, amplify it, and convert it into electromagnetic waves for radiation through the antenna 2.

[0556] In some embodiments, antenna 1 of electronic device 100 is coupled to mobile communication module 150, and antenna 2 is coupled to wireless communication module 160, so that electronic device 100 can communicate with a network and other devices via wireless communication technology. Wireless communication technology may include global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), time-division code division multiple access (TD-SCDMA), long term evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technology. GNSS may include the global positioning system (GPS), the global navigation satellite system (GLONASS), the Beidou navigation satellite system (BDS), the quasi-zenith satellite system (QZSS) and / or the satellite based augmentation system (SBAS).

[0557] The SIM card interface 195 is used to connect a SIM card. The SIM card can be connected to and separated from the electronic device 100 by inserting it into or removing it from the SIM card interface 195. The electronic device 100 can support 1 or N SIM card interfaces, where N is an integer greater than 1. The SIM card interface 195 can support Nano SIM cards, Micro SIM cards, SIM cards, etc. Multiple cards can be inserted into the same SIM card interface 195 at the same time. The types of the multiple cards can be the same or different. The SIM card interface 195 can also be compatible with different types of SIM cards. The SIM card interface 195 can also be compatible with external memory cards. The electronic device 100 interacts with the network through the SIM card to implement functions such as calls and data communications. In some embodiments, the electronic device 100 uses an eSIM, i.e., an embedded SIM card. The eSIM card can be embedded in the electronic device 100 and cannot be separated from the electronic device 100.

[0558] In the embodiment of the present application, an operating system runs on the above components, such as the iOS operating system developed by Apple, the Android open source operating system developed by Google, and the Windows operating system developed by Microsoft.

[0559] The operating system of the electronic device 100 can adopt a layered architecture, an event-driven architecture, a micro-kernel architecture, a microservice architecture, or a cloud architecture. The embodiment of the present application takes the Android system with a layered architecture as an example to illustrate the hardware and software structure of the electronic device 100. It should be noted that although the embodiment of the present application is described using the Android system as an example, its basic principles are also applicable to electronic devices 100 based on operating systems such as iOS or Windows.

[0560] Figure 17 is a software structure block diagram of an electronic device 100 provided in an embodiment of the present application. The software structure adopts a layered architecture, which divides the software into several layers, each with a clear role and division of labor. The layers communicate with each other through software interfaces. Taking the Android system running on an AP as an example, in some embodiments, the Android system is divided into five layers, from top to bottom, namely the application layer, the application framework layer (Framework), the Android runtime (Android runtime) and system library, the hardware abstraction layer (HAL) and the kernel layer (Kernel).

[0561] The application layer may include a series of application packages. Application packages may include camera, gallery, calendar, call, map, wireless local area network (WLAN), Bluetooth, music, video, short message, etc. The application layer may also include system UI (system UI), which is used to display the interface of electronic device 100, such as the signal icon corresponding to the SIM card and the call interface.

[0562] The application framework layer provides an application programming interface (API) and a programming framework for the applications in the application layer. The application framework layer includes some predefined functions. For example, the application framework layer may include a window manager, a content provider, a view system, a phone manager, a resource manager, a notification manager, etc. The phone manager is used to provide call functions for the electronic device 100, such as management of call status (including connecting, hanging up, etc.). The phone manager is represented by telephony in Figure 17. The application framework layer may also include a wireless communication interface layer (radio interface layer, RIL). The modem can exchange information with the telephony through the RIL.

[0563] The modem may include a NAS layer, an RRC layer, a packet data convergence protocol (PDCP) layer, a radio link control protocol (RLC) layer, a medium access control (MAC) layer, and a physical (PHY) layer. Each of the aforementioned layers may be a software module. The modem may interact with the base station via an antenna. Optionally, the method provided in the embodiments of the present application may be implemented by a modem.

[0564] Some embodiments of the present application provide an electronic device, which includes: one or more processors and a memory; the memory is used to store computer program code, and the computer program code includes computer instructions. When the one or more processors execute the computer instructions, the electronic device executes the above-mentioned cell access method.

[0565] Some embodiments of the present application provide a chip system for use in electronic devices. The chip system includes at least one processor and an interface, wherein the interface is configured to receive instructions and transmit them to the at least one processor; the at least one processor executes the instructions, causing the electronic device to perform the cell access method described above. The chip system may be a modem, or a system on chip (SoC) including a modem, and the method described above may be implemented by a modem.

[0566] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server or data center to another website, computer, server or data center via a wired (such as a coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access, or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0567] The above are optional embodiments provided for this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the technical scope disclosed in this application should be included in the scope of protection of this application.

Claims

1. A cell access method, characterized in that: Applied to electronic equipment, the method comprises: receiving a measurement configuration message sent by the first cell, where the measurement configuration message is used to instruct measurement of a signal strength of a neighboring cell of a different system; measuring a signal strength and a signal quality of a second cell, where the second cell is a neighboring cell of a different system of the first cell; At every first preset time duration, the signal strength of the one or more second cells is processed according to the signal quality of the one or more second cells measured within the first preset time duration to obtain the target signal strength of the one or more second cells; Sending a measurement report message to the first cell, where the measurement report message includes a target signal strength of a second cell among the one or more second cells whose target signal strength is higher than a signal strength threshold; If a handover command sent by the first cell is received, a second cell indicated by the handover command is accessed.

2. The method according to claim 1, characterized in that Before the receiving the measurement configuration message sent by the first cell, the method further includes: receiving an invite message sent by the first cell; or, Send an invite message to the first cell.

3. The method according to claim 1 or 2, characterized in that The processing of the signal strengths of the one or more second cells according to the signal quality of the one or more second cells measured within the first preset time period to obtain the target signal strengths of the one or more second cells includes: Determine, according to the signal quality of each second cell among the one or more second cells, a weight corresponding to each second cell; The signal strength of each second cell is multiplied by the corresponding weight to obtain the target signal strength of each second cell.

4. The method according to any one of claims 1 to 3, characterized in that: The sending a measurement report message to the first cell includes: For any one of the one or more second cells, if the target signal strength of the one second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold, sending a measurement report message including the target signal strength of the one second cell to the first cell; The method further comprises: If the target signal strength of the second cell is not higher than the signal strength threshold, and / or if the signal quality of the second cell is lower than the signal quality threshold, a measurement report message including the target signal strength of the second cell is not sent to the first cell.

5. The method according to any one of claims 1 to 3, characterized in that: The sending a measurement report message to the first cell includes: If there are no specific cells among the one or more second cells whose target signal strength is higher than the signal strength threshold and whose target signal strength difference is less than a preset difference value, the measurement report message is sent to the first cell.

6. The method according to claim 5, characterized in that The method further comprises: If the multiple specific cells exist in the one or more second cells, then when the electronic device is in a preset moving state, re-measure the signal strength and signal quality of the multiple specific cells after a second preset time period, and processing the signal strengths of the multiple specific cells according to the signal qualities of the multiple specific cells to obtain target signal strengths of the multiple specific cells; For any specific cell among the multiple specific cells, if the target signal strength of the specific cell increases, a measurement report message including the target signal strength of the specific cell is sent to the first cell; if the target signal strength of the specific cell remains unchanged or decreases, a measurement report message including the target signal strength of the specific cell is not sent to the first cell.

7. The method according to claim 5, characterized in that The method further comprises: If the multiple specific cells exist in the one or more second cells, then when the electronic device is in a preset moving state, re-measure the signal strengths and signal qualities of the multiple specific cells after a second preset time period, and process the signal strengths of the multiple specific cells according to the signal qualities of the multiple specific cells to obtain target signal strengths of the multiple specific cells; For any specific cell among the multiple specific cells, if the target signal strength of the specific cell increases and the signal quality is not lower than the signal quality threshold, a measurement report message including the target signal strength of the specific cell is sent to the first cell; if the target signal strength of the specific cell remains unchanged or decreases, and / or if the signal quality of the specific cell is lower than the signal quality threshold, a measurement report message including the target signal strength of the specific cell is not sent to the first cell.

8. The method according to any one of claims 1 to 7, characterized in that: The method further comprises: If access to the second cell fails, a radio link failure RLF process is triggered; Sending a radio resource control RRC connection reestablishment request message to a target cell, where the target cell is the second cell; Receiving an RRC connection reestablishment message sent by the target cell, where the RRC connection reestablishment message carries signaling radio bearer SRB1 configuration information; Configure SRB1 according to the SRB1 configuration information; Sending an RRC connection reestablishment complete message to the target cell; If the RRC reconfiguration message for configuring SRB2 sent by the target cell is not received after the third preset time period of sending the RRC connection reestablishment completion message, a tracking area update TAU is performed through the SRB1.

9. The method according to any one of claims 1 to 7, characterized in that: The method further comprises: If access to the second cell fails, triggering an RLF process; Sending an RRC connection reestablishment request message to a first target cell, where the first target cell is the second cell; Receiving an RRC connection reestablishment message sent by the first target cell; Sending an RRC connection reestablishment complete message to the first target cell; If the RRC reconfiguration message for configuring SRB2 sent by the first target cell is not received after the fourth preset time of sending the RRC connection reconstruction completion message, the RLF process is triggered and the RRC connection reconstruction process is performed with the second target cell, and the second target cell is the second cell.

10. A cell access method, characterized in that: Applied to electronic equipment, the method comprises: receiving a measurement configuration message sent by the first cell, where the measurement configuration message is used to instruct measurement of a signal strength of a neighboring cell of a different system; measuring a signal strength and a signal quality of a second cell, where the second cell is a neighboring cell of a different system of the first cell; If the signal quality of the second cell is lower than the signal quality threshold, no measurement report message is sent to the first cell. interest; If a redirection message sent by the first cell is received, a second cell is accessed.

11. The method according to claim 10, characterized in that The accessing a second cell includes: Access a second cell whose signal strength is higher than the signal strength threshold and whose signal quality is not lower than the signal quality threshold; or, Access a second cell belonging to the preset cell type.

12. The method according to claim 10 or 11, characterized in that After measuring the signal strength and signal quality of the second cell, the method further includes: If the signal strength of the second cell is higher than the signal strength threshold and the signal quality of the second cell is not lower than the signal quality threshold, a measurement report message is sent to the first cell, where the measurement report message includes the signal strength of the second cell.

13. The method according to any one of claims 10 to 12, characterized in that: The method further comprises: If access to the second cell fails, triggering an RLF process; Sending an RRC connection reestablishment request message to a target cell, where the target cell is the second cell; Receiving an RRC connection reestablishment message sent by the target cell, where the RRC connection reestablishment message carries SRB1 configuration information; Configure SRB1 according to the SRB1 configuration information; Sending an RRC connection reestablishment complete message to the target cell; If the RRC reconfiguration message for configuring SRB2 sent by the target cell is not received after the third preset time period of sending the RRC connection reestablishment completion message, TAU is performed through the SRB1.

14. The method according to any one of claims 10 to 12, characterized in that: The method further comprises: If access to the second cell fails, triggering an RLF process; Sending an RRC connection reestablishment request message to a first target cell, where the first target cell is the second cell; Receiving an RRC connection reestablishment message sent by the first target cell; Sending an RRC connection reestablishment complete message to the first target cell; If the RRC reconfiguration message for configuring SRB2 sent by the first target cell is not received after the fourth preset time of sending the RRC connection reconstruction completion message, the RLF process is triggered and the RRC connection reconstruction process is performed with the second target cell, and the second target cell is the second cell.

15. A cell access method, characterized in that: Applied to electronic equipment, the method comprises: receiving a measurement configuration message sent by the first cell, where the measurement configuration message is used to instruct measurement of a signal strength of a neighboring cell of a different system; measuring a signal strength of a second cell, where the second cell is a neighboring cell of a different system of the first cell; If there are multiple specific cells in the measured second cells whose signal strength is higher than the signal strength threshold and whose signal strength difference is less than a preset difference value, and if the electronic device is in a preset moving state, re-measure the signal strengths of the multiple specific cells after a second preset time period; After re-measuring the signal strengths of the multiple specific cells, sending a measurement report message to the first cell, the measurement report message including the signal strength of the specific cell with increased signal strength among the multiple specific cells; If a handover command sent by the first cell is received, a second cell indicated by the handover command is accessed.

16. The method according to claim 15, characterized in that The measuring the signal strength of the second cell includes: measuring the signal strength and signal quality of the second cell; The sending a measurement report message to the first cell includes: For any one specific cell among the multiple specific cells, if the signal strength of the one specific cell increases and the signal quality of the one specific cell is not lower than the signal quality threshold, sending a measurement report message including the signal strength of the one specific cell to the first cell; The method further comprises: If the signal strength of the one specific cell remains unchanged or decreases, and / or if the signal quality of the one specific cell is lower than a signal quality threshold, a measurement report message including the signal strength of the one specific cell is not sent to the first cell.

17. The method according to claim 15 or 16, characterized in that The method further comprises: If access to the second cell fails, triggering an RLF process; Sending an RRC connection reestablishment request message to a target cell, where the target cell is the second cell; Receiving an RRC connection reestablishment message sent by the target cell, where the RRC connection reestablishment message carries SRB1 configuration information; Configure SRB1 according to the SRB1 configuration information; Sending an RRC connection reestablishment complete message to the target cell; If the RRC reconfiguration message for configuring SRB2 sent by the target cell is not received after the third preset time period of sending the RRC connection reestablishment completion message, TAU is performed through the SRB1.

18. The method according to claim 15 or 16, characterized in that The method further comprises: If access to the second cell fails, triggering an RLF process; Sending an RRC connection reestablishment request message to a first target cell, where the first target cell is the second cell; Receiving an RRC connection reestablishment message sent by the first target cell; Sending an RRC connection reestablishment complete message to the first target cell; If the RRC reconfiguration message for configuring SRB2 sent by the first target cell is not received after the fourth preset time of sending the RRC connection reconstruction completion message, the RLF process is triggered and the RRC connection reconstruction process is performed with the second target cell, and the second target cell is the second cell.

19. A cell access method, characterized in that: Applied to electronic equipment, the method comprises: If the RLF process is triggered, an RRC connection reestablishment request message is sent to the target cell; Receiving an RRC connection reestablishment message sent by the target cell, where the RRC connection reestablishment message carries SRB1 configuration information; Configure SRB1 according to the SRB1 configuration information; Sending an RRC connection reestablishment complete message to the target cell; If the RRC reconfiguration message for configuring SRB2 sent by the target cell is not received after the third preset time period of sending the RRC connection reestablishment completion message, TAU is performed through the SRB1.

20. The method of claim 19, wherein: After the RRC connection reestablishment completion message is sent to the target cell, the method further includes: If the RRC reconfiguration message sent by the target cell is received within a third preset time period of sending the RRC connection reestablishment complete message, configuring SRB2 according to the SRB2 configuration information in the RRC reconfiguration message; TAU is performed through the SRB2.

21. The method according to claim 19 or 20, characterized in that If the RLF process is triggered, before sending the RRC connection reestablishment request message to the target cell, the method further includes: receiving a handover command sent by the first cell, where the handover command is used to instruct handover to a second cell; accessing the one second cell; If access to the second cell fails, the RLF process is triggered.

22. A cell access method, characterized in that: Applied to electronic equipment, the method comprises: If the RLF process is triggered, an RRC connection reestablishment request message is sent to the first target cell; Receiving an RRC connection reestablishment message sent by the first target cell; Sending an RRC connection reestablishment complete message to the first target cell; If the RRC reconfiguration message for configuring SRB2 sent by the first target cell is not received after the fourth preset time of sending the RRC connection reconstruction completion message, the RLF process is triggered and the RRC connection reconstruction process is performed with the second target cell.

23. The method of claim 22, wherein: After sending the RRC connection reestablishment completion message to the first target cell, the method further includes: If the RRC reconfiguration message sent by the first target cell is received after the fourth preset time length of sending the RRC connection reestablishment completion message, a TAU is performed.

24. The method according to claim 22 or 23, characterized in that If the RLF process is triggered, before sending the RRC connection reestablishment request message to the first target cell, the method further includes: receiving a handover command sent by the first cell, where the handover command is used to instruct handover to a second cell; accessing the one second cell; If access to the second cell fails, the RLF process is triggered.

25. An electronic device, characterized in that: The electronic device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the method according to any one of claims 1 to 24 when executed by the processor.

26. A chip system, characterized in that: The chip system is applied to an electronic device, and the chip system includes one or more processors, and the processor is used to call computer instructions so that the electronic device executes the method described in any one of claims 1 to 24.

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