Cell access method, electronic equipment and chip system

Abstract

The invention discloses a cell access method, electronic equipment, a chip system and a storage medium, and belongs to the technical field of communication. 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, and processing the signal strength of the second cell according to the signal quality of the second cell measured within a first preset duration every first preset duration to obtain the target signal strength of the second cell. And sending a measurement report message comprising the target signal strength of the second cell of which the target signal strength is higher than the signal strength threshold to the first cell. And then the electronic equipment receives a switching command sent by the first cell. According to the method and the device, the first cell indicates that the second cell switched to by the electronic equipment is the second cell with relatively good signal strength and signal quality as a whole through the switching command, so that the success rate of accessing the second cell by the electronic equipment is relatively high, and the success rate of a network fallback process is also improved.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a cell access method, an electronic device, and a chip system. Background Art

[0002] When a user equipment (UE) supports the 5th generation mobile networks (5G) standard, the UE usually camps on the 5G network. In this case, if the UE does not support voice over new radio (VONR) calls, the UE needs to use the evolved packet system fallback (EPSFB) technology to fallback from the 5G network to the 4th generation mobile networks (4G) network to make voice over long-term evolution (VOLTE) calls during a call.

[0003] Currently, after the EPSFB process starts, the 5G cell to which the UE is currently attached 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. Then, the 5G cell selects a 4G cell from the one or more 4G cells according to the signal strength of the one or more 4G cells, and sends a handover command to the UE to instruct the UE to switch to this 4G cell. After receiving the handover command, the UE accesses this 4G cell and performs a tracking area update (TAU) to implement the EPSFB process.

[0004] However, in actual situations, due to various factors, the problem of EPSFB process failure is likely to occur. Summary of the Invention

[0005] Embodiments of this application provide a cell access method, an electronic device, and a chip system, which can improve the success rate of the network fallback process.

[0006] In a first aspect, a cell access method is provided. In this method, an electronic device receives a measurement configuration message sent by a first cell, and this measurement configuration message is used to indicate measuring the signal strength of an inter-system neighboring cell. After that, the electronic device measures the signal strength and signal quality of a second cell. The electronic device processes the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within a first preset time interval every first preset 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 this measurement report message includes the target signal strength of the second cells among the one or more second cells whose target signal strength is higher than the signal strength threshold. After that, if the electronic device receives a handover command sent by the first cell, it accesses one second cell indicated by this handover command.

[0007] The second cell is an inter-system neighboring cell of the first cell. The first cell and the second cell support different mobile communication technology standards. Moreover, the mobile communication technology standard supported by the first cell (which can be called the first mobile communication technology standard) is higher than the mobile communication technology standard supported by the second cell (which can be called the second mobile communication technology standard). For example, the first cell supports the 5G standard and the second cell supports the 4G standard. Another example is that the first cell supports the 4G standard and the second cell supports the 3G standard. In this application, the network based on the first mobile communication technology standard is called the first network, and the network based on the second mobile communication technology standard is called the second network.

[0008] Optionally, the signal strength of a cell in this application can be the RSRP of the cell. Of course, the signal strength of the cell can also be characterized by other features of the cell signal, and this application does not make any limitation in this regard.

[0009] Optionally, the signal quality of a cell in this application can be the RSRQ or SINR of the cell, etc. Of course, the signal quality of the cell can also be jointly characterized by these two items or more items of RSRQ and SINR of the cell, and this application does not make any limitation in this regard.

[0010] The target signal strength of the second cell can not only reflect the signal strength of the second cell, but also reflect the signal quality of the second cell. That is to say, the target signal strength of the second cell reflects the comprehensive level of the signal strength and signal quality of the second cell. That is, 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 this one second cell are overall better than those of the other second cell.

[0011] In this 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 the first cell receives the measurement report message sent by the electronic device, the second cell to which the electronic device is instructed to switch through this handover command is a second cell with relatively good overall signal strength and signal quality. Therefore, the success rate of the electronic device when accessing this second cell is relatively high, thus improving the success rate of the network fallback process. In this application, the target signal strength of a cell is relative to the actual signal strength measured for that cell. The target signal strength can be the result obtained after performing some processing on the actual signal strength, and the target signal strength can be greater than or less than the actual signal strength.

[0012] As an example, before receiving the measurement configuration message sent by the first cell, the electronic device can receive the invite message sent by the first cell; or, send the invite message to the first cell.

[0013] Optionally, the electronic device does not support making calls through the first network. In this case, whether the electronic device sends the invite message to the first cell or the first cell sends the invite message to the electronic device, since the electronic device does not support making calls through the first network, both 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.

[0014] For example, when the first network is a 5G network and the second network is a 4G network, this network fallback process can be an EPSFB process. Another example is when the first network is a 4G network and the second network is a 3G network, this network fallback process can be a CSFB process.

[0015] As an example, the operation of the electronic device processing the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within the first preset duration to obtain the target signal strength of the one or more second cells can be: determining the weight corresponding to each second cell according to the signal quality of each second cell in the one or more second cells; multiplying the signal strength of each second cell by the corresponding weight to obtain the target signal strength of each second cell.

[0016] In this 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 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 signal strength.

[0017] As an example, the operation of the electronic device to send a measurement report message to the first cell may be as follows: For any one of the one or more second cells, if the target signal strength of this second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold, then a measurement report message including the target signal strength of this second cell is sent to the first cell. Additionally, if the target signal strength of this second cell is not higher than the signal strength threshold, and / or if the signal quality of this second cell is lower than the signal quality threshold, then a measurement report message including the target signal strength of this second cell is not sent to the first cell.

[0018] In this application, if, after the electronic device receives the measurement configuration message, the signal quality of all the second cells measured is lower than the signal quality threshold, then in this application, the electronic device will never report the target signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will never send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it does not receive the measurement report message sent by the electronic device within the timeout period, it will send a redirection message to the first cell to trigger the electronic device to perform a redirection process. Since the electronic device can select a suitable second cell to access when performing the redirection process, the access success rate is relatively high, thus improving the success rate of the network fallback process.

[0019] As an example, the operation of the electronic device to send a measurement report message to the first cell may be as follows: If there are no multiple specific cells among the one or more second cells whose target signal strength is higher than the signal strength threshold and the difference between the target signal strengths is less than a preset difference, then the measurement report message is sent to the first cell.

[0020] Optionally, if there are the multiple specific cells among the one or more second cells, then when the electronic device is in a preset moving state, after a second preset duration, the signal strength and signal quality of the multiple specific cells are re-measured, 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 one of the multiple specific cells, if the target signal strength of this specific cell increases, then 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, then a measurement report message including the target signal strength of this specific cell is not sent to the first cell.

[0021] In this application, when the electronic device is in a preset moving state and discovers multiple specific cells with a relatively high target signal strength and the same or similar target signal strengths, it will delay reporting the target signal strength of the specific cells with an increased target signal strength to the first cell until the target signal strengths of these multiple specific cells change. Since, compared with a second cell located behind the moving direction of the electronic device, the target signal strength of a second cell located in front of the moving direction of the electronic device will increase as the electronic device moves, the specific cells reported by the electronic device to the first cell are most likely the second cells located in front of the moving direction of the electronic device. In this case, the second cell indicated by the handover command in the first cell 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. Therefore, the success rate of the electronic device in accessing this second cell is relatively high, thus improving the success rate of the network fallback process.

[0022] Optionally, if the multiple specific cells exist in the one or more second cells, when the electronic device is in a preset moving state, after a second preset duration, re-measure the signal strengths and signal qualities of the multiple specific cells, and process the signal strengths of the multiple specific cells according to the signal qualities of the multiple specific cells to obtain the target signal strengths of the multiple specific cells. For any one of 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, send a measurement report message including the target signal strength of this specific cell 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, do not send a measurement report message including the target signal strength of this specific cell to the first cell.

[0023] In this application, if, after the electronic device receives the measurement configuration message, the signal qualities of all the second cells measured are lower than the signal quality threshold, then in this application, the electronic device will never report the target signal strengths of any second cells to the first cell after receiving the measurement configuration message, that is, will never send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it does not receive the measurement report message sent by the electronic device within the timeout period, it will send a redirection message to the first cell to trigger the electronic device to perform a redirection process. Since the electronic device can select a suitable second cell to access when performing the redirection process, the access success rate is relatively high, thus improving the success rate of the network fallback process.

[0024] In a possible manner, if the electronic device fails to access a second cell indicated by the handover command, an RLF procedure is triggered. After that, an RRC connection reestablishment request message may be sent to the target cell, where the target cell is the second cell. An RRC connection reestablishment message sent by the target cell is received, and 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 duration from sending the RRC connection reestablishment complete message, a TAU is performed via SRB1.

[0025] In this application, after the electronic device sends an RRC connection reestablishment complete message to the target cell, if it still does not receive an RRC reconfiguration message for configuring SRB2 sent by the target cell after exceeding the third preset duration, a TAU can be directly performed via SRB1. In this way, the normal progress of the TAU can be ensured, and then the success rate of related network fallback procedures and the like can be improved.

[0026] In another possible manner, if the electronic device fails to access a second cell indicated by the handover command, an RLF procedure is triggered. After that, an RRC connection reestablishment request message may be sent to the first target cell, where the first target cell is the second cell. An RRC connection reestablishment message sent by the first target cell is received; an RRC connection reestablishment complete message is sent to 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 a fourth preset duration from sending the RRC connection reestablishment complete message, an RLF procedure is triggered, and an RRC connection reestablishment procedure is performed with the second target cell, where the second target cell is the second cell.

[0027] In this application, after the electronic device sends an RRC connection reestablishment complete message to the first target cell, if it still does not receive an RRC reconfiguration message for configuring SRB2 sent by the first target cell after exceeding the fourth preset duration, the electronic device no longer continues to wait for the first target cell to send an RRC reconfiguration message, but directly triggers an RLF procedure to replace the cell as soon as possible for the RRC connection reestablishment procedure. In this way, the meaningless long-term waiting of the electronic device in the RRC connection reestablishment procedure can be avoided, and then the success rate of related network fallback procedures and the like can be improved.

[0028] 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, and this measurement configuration message is used to indicate measuring the signal strength of an inter-system neighboring cell. After that, 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 the signal quality threshold, a measurement report message is not sent to the first cell. After that, if the electronic device receives a redirection message sent by the first cell, it accesses a second cell.

[0029] If the signal quality of a certain second cell is not lower than the signal quality threshold, it indicates that the signal quality of this second cell is good; if the signal quality of a certain second cell is lower than the signal quality threshold, it indicates that the signal quality of this second cell is poor.

[0030] 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. Since the electronic device can select a suitable second cell to access when performing the redirection process, the access success rate is relatively high, thus improving the success rate of the network fallback process.

[0031] As an example, the operation for the electronic device to access a second cell can be: 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. Since the signal strength of this second cell is relatively good and the signal quality is also relatively good, the success rate when the electronic device accesses this second cell is relatively high.

[0032] Alternatively, the electronic device accesses a second cell belonging to a preset cell type. The preset cell type can be set in advance. The preset cell type is a cell type with a relatively high access success rate. Therefore, the success rate when the electronic device accesses a second cell belonging to the preset cell type is relatively high.

[0033] 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 make any limitations in this regard. Among them, high-speed rail cells are some cells established along high-speed rail lines, mainly used to solve the problem of poor signals of electronic devices of people taking high-speed rails during the progress of high-speed rails. Since high-speed rail cells are generally dedicated, they are not overly congested. In addition, some operators isolate high-speed rail cells from non-high-speed rail cells. Therefore, it is not easy to have problems when accessing high-speed rail cells. Thus, during the progress of high-speed rails, the success rate of electronic devices of people taking high-speed rails when accessing high-speed rail cells is relatively high, and the network experience after accessing high-speed rail cells is also relatively good.

[0034] As an example, after the electronic device measures the signal strength and signal quality of the second cell, it may also send a measurement report message to the first cell when 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.

[0035] In a possible way, if the electronic device fails to access a second cell after receiving a redirection message, an RLF procedure is triggered. After that, an RRC connection reestablishment request message may be sent to the target cell, where the target cell is the second cell. Receive the RRC connection reestablishment message sent by the target cell, configure SRB1 according to the SRB1 configuration information carried in the RRC connection reestablishment message, and send an RRC connection reestablishment complete message to the target cell. If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the target cell after the third preset duration of sending the RRC connection reestablishment complete message, perform TAU via SRB1.

[0036] In another possible way, if the electronic device fails to access a second cell after receiving a redirection message, an RLF procedure is triggered. After that, an RRC connection reestablishment request message may be sent to the first target cell, where the first target cell is the second cell. Receive the RRC connection reestablishment message sent by the first target cell; send an RRC connection reestablishment complete message 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 duration of sending the RRC connection reestablishment complete message, trigger the RLF procedure and perform an RRC connection reestablishment procedure with the second target cell, where the second target cell is the second cell.

[0037] In a third aspect, a cell access method is provided. In this method, the electronic device receives a measurement configuration message sent by the first cell, and the measurement configuration message is used to indicate measuring the signal strength of an inter-system neighboring cell. After that, measure the signal strength of the second cell, where the second cell is an inter-system neighboring cell 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 signal strength difference is less than a preset difference, and if the electronic device is in a preset moving state, re-measure the signal strength of the multiple specific cells after a second preset duration. After re-measuring the signal strength of the multiple specific cells, send a measurement report message 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. After that, if the electronic device receives a handover command sent by the first cell, access a second cell indicated by the handover command.

[0038] 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 among the multiple specific cells, but will soon move to other positions. That is to say, 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.

[0039] In this case, if the signal strengths of the multiple specific cells are directly reported to the first cell, since the signal strengths of the multiple specific cells are the same or similar, a second cell selected by the first cell may be a second cell located behind the moving direction of the electronic device. When the electronic device is in a preset moving state, the signal strength of this second cell will soon become weaker, so there is a high probability that the electronic device will fail to access this second cell when attempting to access it subsequently.

[0040] Therefore, in order to ensure the success rate of the electronic device accessing the second cell subsequently, in this case, the signal strengths of the multiple specific cells are not reported to the first cell first, but the signal strengths of the multiple specific cells are re-measured after a second preset duration. Since the second preset duration has passed, the signal strengths of the multiple specific cells that were the same or similar before have changed. Among them, the signal strength of the specific cell located in front of the moving direction of the electronic device has become stronger, while the signal strength of the specific cell located behind the moving direction of the electronic device has become weaker.

[0041] In this application, when the electronic device is in a preset moving state, when it is found that there are multiple specific cells with relatively high signal strengths and the signal strengths are the same or similar, it will wait until the signal strengths of the multiple specific cells change, and then report the signal strength of the specific cell with an 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 will increase as the electronic device moves 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 likely to be 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 likely to be 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 success rate of the electronic device accessing this second cell is relatively high, thus improving the success rate of the network fallback process.

[0042] As an example, the operation of the electronic device to measure 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 to send a measurement report message to the first cell may be: for any one of the plurality of 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 send a measurement report message including the signal strength of this specific cell to the first cell. Additionally, 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 do not send a measurement report message including the signal strength of this specific cell to the first cell.

[0043] In a possible manner, if the electronic device fails to access a second cell indicated by the handover command, then an RLF procedure is triggered. After that, an RRC connection reestablishment request message may be sent to the target cell, where the target cell is the second cell. Receive the RRC connection reestablishment message sent by the target cell, configure SRB1 according to the SRB1 configuration information carried in the RRC connection reestablishment message, and send an RRC connection reestablishment complete message to the target cell. If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the target cell after the third preset time period from sending the RRC connection reestablishment complete message, then perform TAU via SRB1.

[0044] In another possible manner, if the electronic device fails to access a second cell indicated by the handover command, then an RLF procedure is triggered. After that, an RRC connection reestablishment request message may be sent to the first target cell, where the first target cell is the second cell. Receive the RRC connection reestablishment message sent by the first target cell; send an RRC connection reestablishment complete message 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 period from sending the RRC connection reestablishment complete message, then trigger an RLF procedure and perform an RRC connection reestablishment procedure with the second target cell, where the second target cell is the second cell.

[0045] In a fourth aspect, a cell access method is provided. In this method, if the electronic device triggers an RLF procedure, then an RRC connection reestablishment request message is sent to the target cell. After that, receive the 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 complete message to the target cell. If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the target cell after the third preset time period from sending the RRC connection reestablishment complete message, then perform TAU via SRB1.

[0046] In the present application, after the electronic device sends an RRC connection reestablishment completion message to the target cell, if it does not receive an RRC reconfiguration message for configuring SRB2 sent by the target cell within a third preset duration, it can directly perform TAU through SRB1. This can ensure the normal progress of TAU, and then improve the success rate of related network fallback processes and the like.

[0047] As an example, if the electronic device receives an RRC reconfiguration message for configuring SRB2 sent by the target cell within the third preset duration after sending the RRC connection reestablishment completion message, it configures SRB2 according to the SRB2 configuration information in the RRC reconfiguration message; and performs TAU through this SRB2. At this time, TAU can proceed normally, and related network fallback processes and the like can also continue to proceed normally.

[0048] As an example, the electronic device can receive a handover command sent by a first cell, and this handover command is used to indicate a handover to a second cell. After that, the electronic device accesses this second cell; if the access to this second cell fails, an RLF process is triggered. In this case, the target cell is the second cell.

[0049] In a fifth aspect, a cell access method is provided. In this method, if the electronic device triggers an RLF process, it sends an RRC connection reestablishment request message to the target cell. After that, it receives an RRC connection reestablishment message sent by a first target cell. It sends an RRC connection reestablishment completion message to 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 a fourth preset duration from sending this RRC connection reestablishment completion message, it triggers an RLF process and performs an RRC connection reestablishment process with a second target cell.

[0050] In the present application, after the electronic device sends an RRC connection reestablishment completion message to the first target cell, if it does not receive an RRC reconfiguration message for configuring SRB2 sent by the first target cell within a fourth preset duration, the electronic device no longer waits for the RRC reconfiguration message sent by the first target cell, but directly triggers an RLF process to quickly change the cell for an RRC connection reestablishment process. In this way, it can avoid the meaningless long-term waiting of the electronic device in the RRC connection reestablishment process, and then improve the success rate of related network fallback processes and the like.

[0051] As an example, if the electronic device receives an RRC reconfiguration message for configuring SRB2 sent by the first target cell after the fourth preset duration from sending this RRC connection reestablishment completion message, it performs TAU. At this time, TAU can proceed normally, and related network fallback processes and the like can also continue to proceed normally.

[0052] As an example, the electronic device can receive a handover command sent by a first cell, and this handover command is used to indicate a handover to a second cell. After that, the electronic device accesses this second cell; if the access to this second cell fails, the RLF process is triggered. In this case, the first target cell and the second target cell are the second cell.

[0053] In a sixth aspect, a chip system is provided. The chip system is applied to an electronic device and includes one or more processors, and the processors are used to call computer instructions to enable the electronic device to execute the above-mentioned cell access method.

[0054] In a seventh aspect, a cell access device is provided. The cell access device has the function of implementing the behavior of 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.

[0055] In an eighth aspect, an electronic device is provided. The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the above-mentioned cell access method is implemented.

[0056] In a ninth aspect, a computer-readable storage medium is provided. Instructions are stored in the computer-readable storage medium, and when the instructions are run on a computer, the computer is enabled to execute the above-mentioned cell access method.

[0057] In a tenth aspect, a computer program product containing instructions is provided. When the computer program product is run on a computer, the computer is enabled to execute the above-mentioned cell access method.

[0058] The technical effects obtained in the above sixth aspect to tenth aspect are similar to the technical effects obtained by the corresponding technical means in the above first aspect to fifth aspect, and will not be elaborated here. Description of the Drawings

[0059] Figure 1 is a schematic diagram of a communication system provided by an embodiment of the present application;

[0060] Figure 2 is a flowchart of a cell handover process provided by an embodiment of the present application;

[0061] Figure 3 is a flowchart of a cell access method provided by an embodiment of the present application;

[0062] Figure 4 is a schematic diagram of another communication system provided by an embodiment of the present application;

[0063] Figure 5 is a schematic diagram of a cell access process provided by an embodiment of the present application;

[0064] Figure 6 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0065] Figure 7 It is a schematic diagram of another cell access process provided by an embodiment of the present application;

[0066] Figure 8 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0067] Figure 9 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0068] Figure 10 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0069] Figure 11 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0070] Figure 12 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0071] Figure 13 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0072] Figure 14 It is a schematic diagram of a TAU process provided by an embodiment of the present application;

[0073] Figure 15 It is a flowchart of another cell access method provided by an embodiment of the present application;

[0074] Figure 16 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present application;

[0075] Figure 17 It is a software structure block diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0076] To make the objectives, technical solutions, and advantages of the present application clearer, the following will further describe the implementation manners of the present application in detail with reference to the accompanying drawings.

[0077] 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. The "and / or" in this article is just 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 simultaneously, and B exists alone. In addition, in order to clearly describe the technical solution of this application, words such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and roles. Those skilled in the art can understand that the words such as "first" and "second" do not limit the quantity and execution order, and the words such as "first" and "second" do not necessarily limit to be different.

[0078] The statements such as "an embodiment" or "some embodiments" described in this application mean that the specific features, structures or characteristics described in the embodiment are included in one or more embodiments of this application. Thus, the statements such as "in an embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments" and the like that appear in different places in this application do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. In addition, the terms "comprise", "include", "have" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0079] The system architecture related to the embodiments of this application will be described below.

[0080] Figure 1 It is a schematic diagram of a communication system provided by an embodiment of this application. Refer to Figure 1 This communication system may include an electronic device 100, a first cell 200, and a second cell 300. The number of the second cells 300 can be one or more.

[0081] The electronic device 100 is within the coverage of the first cell 200 and within the coverage of the second cell 300. The electronic device 100 can access the first cell 200 or the second cell 300.

[0082] The electronic device 100 can also be referred to as a UE. The electronic device 100 can support multiple mobile communication technology standards. For example, it can support the second-generation mobile communication technology (2th generation mobile networks, 2G) standard, the third-generation mobile communication technology (3th generation mobile networks, 3G) standard, 4G standard, 5G standard, etc. Among them, the 4G standard can also be referred to as the long term evolution (LTE) standard.

[0083] Exemplarily, 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, a vehicle-mounted device, an augmented reality (AR) device, a virtual reality (VR) device, a laptop computer, an ultra-mobile personal computer (UMPC), a netbook, a personal digital assistant (PDA), a laptop, etc. The embodiments of the present application do not limit this.

[0084] The second cell 300 is an inter-system neighbor cell of the first cell 200. That is, the first cell 200 and the second cell 300 support different mobile communication technology standards. Moreover, 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, if the first cell 200 supports the 5G standard, the first cell 200 can be referred to as a 5G cell in this case; if the second cell 300 supports the 4G standard, the second cell 300 can be referred to as a 4G cell in this case. Another example is that if the first cell 200 supports the 4G standard, the first cell 200 can be referred to as a 4G cell in this case; if the second cell 300 supports the 3G standard, the second cell 300 can be referred to as a 3G cell in this case. Optionally, a 5G cell can also be referred to as a new radio (NR) cell. A 4G cell can also be referred to as an LTE cell.

[0085] 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. The electronic device 100 communicating with this cell 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.

[0086] It should be noted that in the embodiments of the present application, the electronic device 100 can support the first mobile communication technology standard and the second mobile communication technology standard, and 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. Among them, in the embodiments of the present 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.

[0087] The first mobile communication technology standard can be the highest mobile communication technology standard among the multiple mobile communication technology standards that the electronic device 100 can support. In this case, the electronic device 100 should stay in the first network as much as possible under normal circumstances to ensure a high residence ratio in the first network.

[0088] In some embodiments, the electronic device 100 does not support making calls through the first network. In this case, when the electronic device 100 needs to make a call, it can fall back from the first network to the second network to make a call. Among them, when the electronic device 100 falls back from the first network to the second network, it will switch from the first cell 200 to the second cell 300.

[0089] For example, the electronic device 100 can support up to the 5G standard at most. 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 stay in the 5G network as much as possible under normal circumstances. However, the electronic device 100 does not support making calls through the 5G network, that is, the electronic device 100 does not support VONR calls. Then when the electronic device 100 needs to make a call, it can use the EPSFB technology to fall back from the 5G network to the 4G network to use VOLTE calls. Among them, during the EPSFB process, the electronic device 100 will switch from the 5G cell to the 4G cell.

[0090] For another example, the electronic device 100 supports up to the 4G standard at most. 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 stay in the 4G network as much as possible under normal circumstances. However, the electronic device 100 does not support making calls through the 4G network, that is, the electronic device 100 does not support VOLTE calls. Then, when the electronic device 100 needs to make a call, it can use the circuit switched fallback (CSFB) technology to fall back from the 4G network to the 3G network to make a 3G call. During the CSFB process, the electronic device 100 will switch from the 4G cell to the 3G cell.

[0091] Next, taking the first network as the 5G network, the first cell as the 5G cell, the second network as the 4G network, and the second cell as the 4G cell as an example, the cell handover process during the EPSFB process will be described exemplarily. It can be understood that the cell handover process during the CSFB process when the first network is the 4G network, the first cell is the 4G cell, the second network is the 3G network, and the second cell is the 3G cell is similar, and the embodiments of the present application will not elaborate on this again.

[0092] Figure 2 It is a flowchart of a cell handover process provided by an embodiment of the present application. Refer to Figure 2 In this case, the cell handover process may include the following steps 201 to 217.

[0093] Step 201: The electronic device accesses the 5G cell.

[0094] When the electronic device accesses the 5G cell, the electronic device is in the radio resource control (RRC) connected state. At this time, the electronic device stays in the 5G cell.

[0095] In some embodiments, the electronic device does not support VONR calls.

[0096] Step 202: The 5G cell sends an invite message to the electronic device.

[0097] The 5G cell sending an invite message to the electronic device means that the electronic device is called by the calling device as the called device.

[0098] It should be noted that in step 202, it may also be that the electronic device sends an invite message to the 5G cell. In this case, the electronic device calls the called device as the calling device.

[0099] 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.

[0100] Step 203: The 5G cell sends a measurement configuration message to the electronic device.

[0101] Exemplarily, the measurement configuration message may be an RRC connection reconfiguration message carrying a measConfig cell.

[0102] The measurement configuration message is used to instruct the electronic device to measure the signal strength of a neighboring cell in a different system.

[0103] Exemplarily, the measurement configuration message may include B1 event information. The B1 event information may include the threshold of the B1 event. The B1 event is used to indicate that the signal strength of a neighboring cell in a different system is higher than the threshold. 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 in a different system is higher than the threshold.

[0104] Step 204: The electronic device measures the signal strength of the 4G cell.

[0105] The 4G cell is a neighboring cell in a different system of the 5G cell to which the electronic device is currently connected.

[0106] If the electronic device is within the coverage area of a certain 4G cell, it can measure the signal strength of this 4G cell.

[0107] Step 205: The electronic device sends a measurement report message to the 5G cell.

[0108] When the electronic device measures that the signal strength of a certain 4G cell is higher than the threshold, it can send a measurement report message to the 5G cell.

[0109] The measurement report message includes the physical cell identifier (PCI) and the signal strength of the 4G cell whose signal strength is higher than the threshold.

[0110] It is assumed here that the electronic device is within the coverage area of 4G cell A and within the coverage area 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 value, it sends a measurement report message including the PCI and signal strength of 4G cell A to the 5G cell. Also, 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 value, it sends a measurement report message including the PCI and signal strength of 4G cell B to the 5G cell.

[0111] The 5G cell can select a 4G cell from the 4G cells according to the signal strength of the 4G cells included in the measurement report message sent by the electronic device. For example, it can select the 4G cell with the highest signal strength. Then the 5G cell can instruct the electronic device to switch to this 4G cell, as described below.

[0112] Step 206: The 5G cell sends a handover command to the electronic device.

[0113] Exemplarily, the handover command can be an RRC connection reconfiguration message carrying a mobility control (mobilityControlInfo) cell.

[0114] Optionally, the handover command can include the radio parameters required when switching to the 4G cell, such as the PCI of the 4G cell to be switched to, the radio bearer (RB) configuration information, etc.

[0115] The RB configuration information is the configuration information related to the RB. For example, the RB configuration information can include the configuration information related to signalling radio bearer (SRB) 1, SRB2, and data radio bearer (DRB).

[0116] Among them, the SRB is the actual transmission channel of the signalling message. SRB1 is used to carry RRC messages and can also carry some non-access stratum (NAS) messages. SRB2 is used to carry NAS messages. Among them, the DRB is the actual transmission channel of the user data.

[0117] It is assumed here that the handover command includes the radio parameters required when switching to 4G cell A, that is, the handover command is used to instruct switching to 4G cell A. Then after receiving the handover command, the electronic device can camp on 4G cell A.

[0118] Step 207: The electronic device attempts to access 4G cell A but fails.

[0119] Optionally, the electronic device may attempt to access 4G cell A according to the radio parameters included in the handover command.

[0120] Exemplarily, the electronic device may attempt to access 4G cell A in a random access manner (including but not limited to a non-competitive random access manner) according to the radio parameters included in the handover command.

[0121] 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. In the case where the signal quality of 4G cell A is relatively poor, it is very likely that the electronic device will fail to access when attempting to access 4G cell A.

[0122] Step 208: The electronic device triggers a radio link failure (RLF) process and selects 4G cell B.

[0123] The RLF process involves a cell selection process and an RRC connection reestablishment process, and the RRC connection reestablishment process aims to reestablish the RRC connection. Then, after the electronic device triggers the RLF process, it can first select a 4G cell. Here, it is assumed that 4G cell B is selected. Then, the electronic device can camp on 4G cell B and then establish an RRC connection with 4G cell B, which is described in detail as follows.

[0124] Step 209: The electronic device sends a connection reestablishment request message to 4G cell B.

[0125] Optionally, the connection reestablishment request message may carry a reestablishment reason. Exemplarily, the reestablishment reason triggered by RLF may be "otherFailure".

[0126] Step 210: 4G cell B sends a connection reestablishment message to the electronic device.

[0127] After receiving the connection reestablishment request message, 4G cell B may send a connection reestablishment message to the electronic device. Exemplarily, the connection reestablishment message may carry SRB1 configuration information. The SRB1 configuration information is the configuration information related to SRB1.

[0128] Step 211: The electronic device sends a connection reestablishment complete message to 4G cell B.

[0129] 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 the RRC connection reestablishment complete message to 4G cell B through SRB1.

[0130] Since the cell where the electronic device camps has changed, the electronic device will find that the tracking area (TA) or TAlist where it is located has changed. Among them, one TAlist contains multiple TAs. In this case, after the electronic device establishes an RRC connection with 4G cell B, it needs to perform a TAU to notify the network side (including the access network and core network of the 4G network) of the TA where it is currently located.

[0131] In the related art, the electronic device can perform a TAU through SRB1 in the RRC idle state. And the electronic device can only perform a TAU through SRB2 in the RRC connected state and cannot perform a TAU through SRB1. Therefore, after the electronic device sends the RRC connection reestablishment complete message to 4G cell B, it needs to wait for the RRC reconfiguration message sent by 4G cell B carrying the SRB2 configuration information and DRB configuration information to configure SRB2 and DRB, and then can perform a TAU through SRB2.

[0132] However, in some actual scenarios, the following phenomenon occurs: After the electronic device sends the RRC connection reestablishment complete message to 4G cell B, 4G cell B does not send the RRC reconfiguration message carrying the SRB2 configuration information and DRB configuration information to the electronic device, but sends an RRC connection release message to the electronic device after a period of time (generally about 5 seconds). After analysis, the reason for this situation may be that after 4G cell B receives the RRC connection reestablishment complete message sent by the electronic device, since it does not find the electronic device using the RRC connection to transmit data for a long time, it sends the RRC connection release message to the electronic device.

[0133] Step 212: 4G cell B sends an RRC connection release message to the electronic device.

[0134] Step 213: The electronic device triggers the TAU process.

[0135] After the electronic device receives the RRC connection release message, it will release the RRC connection with 4G cell B. After the RRC connection is released, the electronic device is in the RRC idle state. After the electronic device is in the RRC idle state, it will trigger the TAU process.

[0136] After the electronic device triggers the TAU process, it will first establish an RRC connection with 4G cell B, and then perform a TAU through SRB1, as described below.

[0137] Step 214: The electronic device sends an RRC connection request message to 4G cell B.

[0138] Step 215: 4G cell B sends an RRC connection setup message to the electronic device.

[0139] After receiving the RRC connection request message sent by the electronic device, 4G cell B can send an RRC connection setup message to the electronic device. Exemplarily, the RRC connection setup message may carry SRB1 configuration information.

[0140] Step 216: The electronic device sends an RRC connection setup complete message to 4G cell B, and the RRC connection setup complete message contains a TAU request message at the NAS layer.

[0141] After receiving the RRC connection setup message sent by 4G cell B, the electronic device can configure SRB1 according to the SRB1 configuration information in the RRC connection setup message, and then can send the RRC connection setup complete message to 4G cell B through SRB1.

[0142] Exemplarily, the TAU request message may include the tracking area identity (TAI) of the TA where the electronic device is currently located.

[0143] After the electronic device sends the RRC connection setup complete message to 4G cell B, 4G cell B should have returned a TAU accept message at the NAS layer to the electronic device. However, in some actual scenarios, 4G cell B did not return a TAU accept message to the electronic device, but returned a TAU reject message at the NAS layer, and the attached rejection cause value was #10 implicitly detached. After analysis, the reason for this situation may be that: 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 reject message is returned to the electronic device.

[0144] Step 217: 4G cell B sends a TAU reject message to the electronic device.

[0145] After the electronic device receives the TAU rejection message sent by the 4G cell B, it can determine that the EPSFB process fails, resulting in a call failure. When the electronic device is the calling device, it is a calling failure; when the electronic device is the called device, it is a called failure. After that, the electronic device can initiate an attach process to attempt to continue accessing the 4G cell B.

[0146] Analyzing the root cause of the above call failure, it may be that after the electronic device sends the RRC connection reestablishment complete message to the 4G cell B in step 211, the electronic device has been waiting for the RRC reconfiguration message carrying the SRB2 configuration information and DRB configuration information sent by the 4G cell B but has not received it, resulting in the electronic device waiting for too long (i.e., 5 seconds mentioned above). The electronic device waiting for too long after sending the RRC connection reestablishment complete message to the 4G cell B will not only cause the 4G cell B in step 211 to send an RRC connection release message to the electronic device, but also cause the 4G cell B in step 217 to send a TAU rejection message to the electronic device.

[0147] Moreover, the long waiting time of the electronic device is very likely to cause the fallback timer of the electronic device to time out. That is to say, even if the 4G cell B returns a TAU acceptance message to the electronic device after step 216, the EPSFB process will still fail due to the timeout of the fallback timer of the electronic device, resulting in a call failure.

[0148] From the above Figure 2 It can be seen from the cell handover process described in the embodiment that there are mainly two problems in this process: on the one hand, in step 207, the electronic device attempts to access the 4G cell A but fails. On the other hand, after the electronic device sends the RRC connection reestablishment complete message to the 4G cell B in step 211, the electronic device waits for too long.

[0149] Therefore, the embodiment of the present application provides a cell access method to solve the above two problems, avoid the failure of the EPSFB process, and improve the call success rate.

[0150] The cell access method provided by the embodiment of the present application will be explained in detail below.

[0151] In a possible implementation manner, the cell access method provided by the embodiment of the present application is used to solve the problem that in step 207 of the above Figure 2 embodiment, the electronic device attempts to access the 4G cell A but fails. The following will be described in detail in the Figure 3 embodiment below.

[0152] Figure 3It is a flowchart of a cell access method provided by an embodiment of the present application. Refer to Figure 3 , the method includes the following steps:

[0153] Step 301: The electronic device accesses the first cell.

[0154] The first cell has been explained in detail in the above Figure 1 embodiment, and the embodiments of the present application will not repeat it here.

[0155] When the electronic device accesses the first cell, the electronic device is in the RRC connected state. At this time, the electronic device camps on the first cell.

[0156] 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.

[0157] When the electronic device sends an invite message to the first cell, it means that the electronic device calls the called device as the calling device. When the first cell sends an invite message to the electronic device, it means that the electronic device is called by the calling device as the called device.

[0158] 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 making 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, so that the electronic device can make subsequent calls through the second network.

[0159] For example, when the first network is a 5G network and the second network is a 4G network, this network fallback process can be an EPSFB process. Another example is when the first network is a 4G network and the second network is a 3G network, this network fallback process can be a CSFB process.

[0160] In the embodiments of the present application, this network fallback process can at least include the following steps 303 to 308.

[0161] Step 303: The first cell sends a measurement configuration message to the electronic device.

[0162] Exemplarily, this measurement configuration message can be an RRC connection reconfiguration message carrying a measConfig cell. This measConfig cell can contain measurement frequency points.

[0163] This measurement configuration message is used to instruct the electronic device to measure the signal strength of the inter-system neighboring cell.

[0164] Exemplarily, the measurement configuration message may include B1 event information. The B1 event information may include a threshold value of the B1 event. The B1 event is used to indicate that the signal strength of an inter-system neighboring cell is higher 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 the inter-system neighboring cell is higher than the threshold value.

[0165] Step 304: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0166] The second cell has been Figure 1 explained in detail in the above embodiments, and the embodiments of the present application will not repeat it here.

[0167] If the electronic device is within the coverage of a certain second cell, this second cell is the inter-system neighboring cell of the first cell to which the electronic device is currently connected. In some embodiments, if this second cell is the cell corresponding to the measurement frequency band carried in the measurement configuration message, the electronic device may continuously measure the signal strength and signal quality of this second cell.

[0168] Optionally, in the embodiments of the present application, the signal strength of the cell 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 features of the cell signal, and the embodiments of the present application do not limit this.

[0169] Optionally, in the embodiments of the present application, the signal quality of the cell may be the reference signal received quality (RSRQ) of the cell, or the signal to interference plus noise ratio (SINR), etc. Of course, the signal quality of the cell may also be jointly characterized by two or more of the RSRQ and SINR of the cell, and the embodiments of the present application do not limit this.

[0170] In the embodiments of the present application, after receiving the measurement configuration message sent by the first cell, the electronic device can not only measure the signal strength of the second cell, but also measure the signal quality of the second cell. Moreover, the electronic device can process the signal strength of the second cell according to the signal quality of the second cell and then report it to the first cell, as described below.

[0171] Step 305: After receiving the measurement configuration message, the electronic device processes the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within the first preset duration every first preset duration, to obtain the target signal strength of the one or more second cells.

[0172] The first preset duration can be set in advance. The first preset duration can be set to be relatively short. For example, the first preset duration can be 300 milliseconds, 500 milliseconds, etc., and the embodiments of the present application do not limit this. It should be noted that after the first cell sends the measurement configuration message, a timeout period will be set, and the first preset duration is less than this timeout period.

[0173] For the sake of convenience of description, hereinafter, 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 duration, the target signal strength of each second cell in 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.

[0174] The target signal strength of the second cell can not only reflect the actual signal strength of the second cell, but also reflect the signal quality of the second cell. That is to say, the target signal strength of the second cell reflects the comprehensive level of the actual signal strength and signal quality of the second cell. That is, 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 this one second cell are overall better than those of the other second cell.

[0175] For example, if the actual signal strength of the second cell A is the same as that of the second cell B, but the signal quality of the second cell A is higher than that of the second cell B, then the target signal strength of the second cell A will be higher than that of the second cell B.

[0176] Another example is that if the actual signal strength of the second cell A is lower than that of the second cell B, and the signal quality of the second cell A is also lower than that of the second cell B, then the target signal strength of the second cell A will be lower than that of the second cell B.

[0177] Still another example is that if the actual signal strength of the second cell A is lower than that of the second cell B, but the signal quality of the second cell A is higher than that of the second cell B, then it depends 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 to determine the high or low of the target signal strength of the second cell A and the target signal strength of the second cell B.

[0178] Suppose the actual signal strength of the second cell A is slightly lower than that of the second cell B, and the signal quality of the second cell A is much higher than that of the second cell B. Then the target signal strength of the second cell A will be higher than that of the second cell B. Or, suppose the actual signal strength of the second cell A is much lower than that of the second cell B, and the signal quality of the second cell A is slightly higher than that of the second cell B. Then the target signal strength of the second cell A will be lower than that of the second cell B.

[0179] In some embodiments, the operation in step 305 may be: The electronic device determines the weight corresponding to each of the one or more second cells according to the signal quality of each of the one or more second cells; multiplies the actual signal strength of each of the one or more second cells by the corresponding weight to obtain the target signal strength of each of the one or more second cells.

[0180] In this case, the actual signal strength of each of the one or more second cells is weighted according to the signal quality of each of the one or more second cells to obtain the target signal strength of each of the one or more second cells. In this way, the target signal strength of each of the one or more second cells can reflect the signal quality to a certain extent while mainly reflecting the actual signal strength.

[0181] It should be noted that for any one of the one or more second cells, the greater the signal quality of this second cell, the greater the weight corresponding to this second cell; the smaller the signal quality of this second cell, the smaller the weight corresponding to this second cell.

[0182] Optionally, the operation of the electronic device determining the weight corresponding to each of the one or more second cells according to the signal quality of each of the one or more second cells may be: For any one of the one or more second cells, divide the signal quality of this second cell by the maximum signal quality among the signal qualities of the one or more second cells to obtain the weight corresponding to this second cell. Of course, the electronic device may also determine the weight corresponding to each of the one or more second cells in other ways according to the signal quality of each of the one or more second cells, and the embodiments of the present application do not limit this.

[0183] Step 306: The electronic device sends a measurement report message to the first cell.

[0184] The measurement report message includes the target signal strength of the second cells among the one or more second cells whose target signal strength is higher than the signal strength threshold. Exemplarily, the measurement report message may further include the cell identifier (including but not limited to PCI) of the second cell.

[0185] The signal strength threshold can be set in advance. Exemplarily, the signal strength threshold can be the threshold value of event B1 included in the measurement configuration message.

[0186] It should be noted that after the electronic device receives the measurement configuration message, every first preset time period, it can not only obtain the target signal strength of one or more second cells measured within the first preset time period, but also, when there is a second cell among the one or more second cells whose target signal strength is higher than the signal strength threshold, send a measurement report message to the first cell.

[0187] Exemplarily, 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 can include the target signal strength of this second cell, and further can also include the cell identifier of this second cell, etc.

[0188] Exemplarily, 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 can send a measurement report message to the first cell. This measurement report message can include the target signal strength of each of the at least two second cells, and further can also include the cell identifier of each of the at least two second cells, etc.; or, the electronic device can send at least two measurement report messages to the first cell. Each measurement report message in the at least two measurement report messages can include the target signal strength of one of the at least two second cells, and further can also include the cell identifier of this second cell, etc.; or, the electronic device can send at least one measurement report message to the first cell. Each measurement report message in the at least one measurement report message can include the target signal strength of at least one of the at least two second cells, and further can also include the cell identifier of each of the at least one second cells, etc.

[0189] After the first cell receives the measurement report message sent by the electronic device, it can select a second cell according to the target signal strength of the second cell included in the measurement report message sent by the electronic device. For example, it can select a second cell with the highest target signal strength. Then the first cell can instruct the electronic device to switch to this second cell.

[0190] 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 according to the target signal strength of the second cell is a second cell with relatively good overall actual signal strength and signal quality.

[0191] Step 307: The first cell sends a handover command to the electronic device.

[0192] Exemplarily, the handover command may be an RRC connection reconfiguration message carrying a mobilityControlInfo cell.

[0193] Optionally, the handover command may include radio parameters required when switching to the second cell, such as the cell identifier of the second cell to be switched to, RB configuration information, etc.

[0194] Step 308: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0195] Optionally, the electronic device may access this second cell according to the radio parameters included in the handover command.

[0196] Exemplarily, the electronic device may access this second cell in a random access manner (including but not limited to a non-competitive random access manner) according to the radio parameters included in the handover command.

[0197] Since this second cell is a second cell with relatively good overall actual signal strength and signal quality, the electronic device is likely to succeed in accessing this second cell when attempting to access it.

[0198] If the electronic device successfully accesses this second cell, it may continue to perform other operations to complete the network fallback process. After the electronic device completes the network fallback process, that is, successfully falls back from the first network to the second network, then the electronic device can make a call through the second network.

[0199] Next, in combination with Figure 4 and Figure 5 an exemplary description of a possible implementation manner for the electronic device to access this second cell is given.

[0200] As an example, as Figure 4 shown, the communication system in the embodiments 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.

[0201] The access network is responsible for using a certain wired or wireless connection and communication technology to converge a large number of end users level by level into the core network to achieve connection to the network. The access network is the edge part of the entire network, the part closest to the user, and is usually also called the "last mile".

[0202] Exemplarily, the access network of a 5G network includes 5G cells, and the base stations of 5G cells (i.e., gNBs) can be referred to as access network devices in the 5G network. Exemplarily, the access network of a 4G network includes 4G cells, and the base stations of 4G cells (i.e., eNBs) can be referred to as access network devices in the 4G network.

[0203] The main functions of the core network are to provide user connections, user management, and bearer services for services, and to provide an interface to external networks as a bearer network. The establishment of user connections includes functions such as mobility management (MM), call management (CM), switching / routing, and announcement recording (to complete the connection relationship to the intelligent network peripheral device in combination with intelligent network services).

[0204] Exemplarily, the core network of a 5G network is 5G Core (which can be abbreviated as 5GC for short). 5GC can use general network function virtualization devices to replace the dedicated communication devices of the 4G network. Exemplarily, the core network of a 4G network is the evolved packet core (EPC). EPC has the traditional capabilities of mobile networks such as user subscription data storage, mobility management, and data exchange, and can provide users with an ultra-high-speed Internet experience.

[0205] In the embodiments of the present application, the first cell belongs to the access network of the first network, and the base station of the first cell is the access network device in the first network. Exemplarily, it is assumed that the first cell is a 5G cell. When the electronic device camps on the 5G cell, the electronic device communicates with the gNB of the 5G cell, and the gNB communicates with the 5GC.

[0206] The second cell belongs to the access network of the second network, and the base station of the second cell is the access network device in the second network. Exemplarily, it is assumed that the second cell is a 4G cell. When the electronic device camps on the 4G cell, the electronic device communicates with the eNB of the 4G cell, and the eNB communicates with the EPC.

[0207] In some embodiments, the process in which the electronic device accesses a second cell indicated by the handover command in step 308 involves interactions among the electronic device, the access network device of the second network (i.e., the base station of the second cell), and the core network of the second network.

[0208] Assume that in step 308, the electronic device accesses the second cell using a non-competitive random access method. Then, the handover command sent by the first cell to the electronic device in step 307 may further include a non-conflicting random access preamble assigned to the electronic device. In this case, the handover command may also be referred to as a MSG0 message.

[0209] 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 handover command in step 308 involves the interaction among the electronic device, the eNB of the 4G cell, and the EPC, as described in detail below Figure 5 in the embodiments

[0210] Figure 5 is a schematic diagram of a cell access process provided by an embodiment of the present application. Refer to Figure 5 and the cell access process may include the following steps 501 to 508

[0211] Step 501: The electronic device sends a random access preamble to the eNB of the 4G cell

[0212] Exemplarily, the electronic device may send the random access preamble 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

[0213] Exemplarily, the electronic device may carry the random access preamble in a MSG1 message and send it to the eNB

[0214] Step 502: After receiving the random access preamble, the eNB sends a random access response message to the electronic device

[0215] Exemplarily, the random access response message may also be referred to as a MSG2 message

[0216] It should be noted that the electronic device has actually accessed the 4G cell after receiving the random access response message sent by the eNB. However, since the cell where the electronic device camps has changed, the electronic device needs to perform TAU after accessing the 4G cell to notify the network side (i.e., the eNB and the EPC) of its current TA. Therefore, after receiving the random access response message, the electronic device will also execute the following steps 503 to 508 to perform TAU

[0217] Step 503: After receiving the random access response message, the electronic device sends a RRC connection reconfiguration complete message to the eNB, and the RRC connection reconfiguration complete message contains a TAU request message

[0218] In some embodiments, after receiving the handover command, the electronic device may first configure relevant RBs according to the RB configuration information in the handover command. For example, it may configure SRB1, SRB2, and DRB. In this case, in step 503, the electronic device may send the RRC connection reconfiguration complete message to the eNB through SRB1.

[0219] Exemplarily, the TAU request message may include the TAI of the TA where the electronic device is currently located.

[0220] Step 504: After receiving the RRC connection reconfiguration complete message, the eNB sends an initial UE message to the EPC, and the initial UE message contains the TAU request message.

[0221] Step 505: After receiving the initial UE message, the EPC sends a downlink NAS transport message to the eNB, and the downlink NAS transport message contains the TAU accept message.

[0222] Optionally, after receiving the initial UE message, if the EPC determines that the electronic device is accessing for the first time, then the EPC may authenticate the electronic device (authentication / security) to create some security-related parameters for the electronic device.

[0223] Optionally, after receiving the initial UE message, the EPC may update the TA or TA list of the electronic device, and after the update, it will send a downlink NAS transport message containing the TAU accept message to the eNB.

[0224] Step 506: After receiving the downlink NAS transport message, the eNB sends a downlink information transfer message to the electronic device, and the downlink information transfer message contains the TAU accept message.

[0225] Step 507: After receiving the downlink information transfer message, the electronic device sends an uplink information transfer message to the eNB, and the uplink information transfer message contains the NAS layer TAU complete message.

[0226] Optionally, the electronic device may send the uplink information transfer message to the eNB through SRB2.

[0227] Step 508: After receiving the uplink information transmission message, the eNB sends an uplink NAS transport message to the EPC. The uplink NAS transport message contains a TAU completion message.

[0228] After the EPC receives the TAU completion message, the TAU procedure is completed.

[0229] Thus, the electronic device has completed the cell access procedure and the related TAU procedure. After that, the electronic device can continue to perform other operations to complete the EPSFB procedure. After the electronic device completes the EPSFB procedure, it successfully falls back from the 5G network to the 4G network, and then the electronic device can make a call through the 4G network.

[0230] It should be noted that the embodiments of the present application only use the above Figure 5 embodiment as an example to exemplarily illustrate the process of the electronic device accessing the second cell in step 308. The above Figure 5 embodiment does not limit the embodiments of the present application. The electronic device can also access the second cell through other methods different from the above Figure 5 embodiment, and the embodiments of the present application do not limit this.

[0231] It should be noted that the above Figure 3 embodiment only takes the call scenario triggering the network fallback procedure as an example for exemplary illustration. In practical applications, the network fallback procedure triggered by other scenarios can also be implemented by the cell access method provided by the embodiments of the present application. That is to say, in the case where the electronic device accesses the first cell in step 301 in the embodiments of the present application, not only can the network fallback procedure described in steps 303 to 308 be triggered in the scenario described in step 302, but also the network fallback procedure described in steps 303 to 308 can be triggered in other scenarios where there is a network fallback requirement. The cell access method provided by the embodiments of the present application can improve the success rate of the network fallback procedure triggered in various scenarios.

[0232] In an embodiment of the present application, after receiving a measurement configuration message sent by a first cell, an electronic device can not only measure the actual signal strength of a second cell, but also measure the signal quality of the second cell. Moreover, every first preset time period, the electronic device can process the actual signal strength of 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 electronic device can send a measurement report message including the target signal strength of the second cell whose target signal strength is higher than the signal strength threshold to the first cell. After that, the electronic device can receive a handover command sent by the first cell. 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, after receiving the measurement report message sent by the electronic device, the first cell instructs the electronic device to hand over to a second cell with relatively good overall actual signal strength and signal quality through the handover command. Therefore, the success rate of the electronic device when accessing this second cell is relatively high, thus improving the success rate of the network fallback process.

[0233] In a possible implementation manner, the cell access method provided in the embodiment of the present application is used to solve the problem that in step 207 of the above Figure 2 embodiment, the electronic device attempts to access 4G cell A but fails. The following will be described in detail in the Figure 6 embodiment below.

[0234] Figure 6 is a flowchart of a cell access method provided in the embodiment of the present application. Refer to Figure 6 The method includes the following steps:

[0235] Step 601: The electronic device accesses the first cell.

[0236] The operation of step 601 is similar to the operation of step 301 in the above Figure 3 embodiment, and the embodiment of the present application will not elaborate on this.

[0237] 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.

[0238] The operation of step 602 is similar to the operation of step 302 in the above Figure 3 embodiment, and the embodiment of the present application will not elaborate on this.

[0239] 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 making 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 is triggered so that the electronic device can make subsequent calls through the second network. In the embodiments of the present application, this network fallback process may at least include the following steps 603 to 607.

[0240] Step 603: The first cell sends a measurement configuration message to the electronic device.

[0241] The operation of step 603 is similar to the operation of step 303 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0242] Step 604: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0243] The operation of step 604 is similar to the operation of step 304 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0244] After the electronic device measures the signal strength and signal quality of a certain second cell, it can determine whether the signal strength of this second cell is higher than the signal strength threshold and determine whether the signal quality of this second cell is lower than the signal quality threshold.

[0245] The signal quality threshold can be set in advance. If the signal quality of a certain second cell is not lower than the signal quality threshold, it means that the signal quality of this second cell is good; if the signal quality of a certain second cell is lower than the signal quality threshold, it means that the signal quality of this second cell is poor.

[0246] If the electronic device measures that the signal strength of a certain second cell is higher than the signal strength threshold and the signal quality of this second cell is not lower than the signal quality threshold, the electronic device reports the signal strength of this second cell to the first cell, that is, the electronic device sends a measurement report message including the signal strength of this second cell to the first cell. After receiving the measurement report message, the first cell can send a handover command to the electronic device. After receiving the handover command, the electronic device can access one of the second cells indicated by the handover command.

[0247] Among them, the operation of the first cell sending a handover command to the electronic device is similar to the operation of step 307 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0248] Among them, the operation of the electronic device accessing one of the second cells indicated by the handover command is similar to the operation in the above Figure 3The operation of step 308 in the embodiments is similar, and the embodiments of the present application will not elaborate on this again.

[0249] If the electronic device measures that the signal strength of a certain second cell is not higher than the signal strength threshold, the electronic device does not report the signal strength of this second cell to the first cell, that is, the electronic device does not send a measurement report message including the signal strength of this second cell to the first cell.

[0250] If the electronic device measures that the signal strength of a certain second cell is higher than the signal strength threshold, but the signal quality of this second cell is lower than the signal quality threshold, the electronic device does not report the signal strength of this second cell to the first cell, that is, the electronic device does not send a measurement report message including the signal strength of this second cell to the first cell.

[0251] 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 this second cell is lower than the signal quality threshold, the electronic device does not report the signal strength of this second cell to the first cell, that is, the electronic device does not send a measurement report message including the signal strength of this second cell to the first cell, as specifically described in step 605 below.

[0252] 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.

[0253] If the signal quality of a certain second cell is lower than the signal quality threshold, it indicates that the signal quality of this second cell is relatively poor. In this case, the electronic device does not send a measurement report message including the signal strength of this second cell to the first cell.

[0254] It should be noted that if after the electronic device receives the measurement configuration message, the signal quality of all the second cells measured is lower than the signal quality threshold, then in the embodiments of the present application, the electronic device will never report the signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will never send a measurement report message to the first cell. And after the first cell sends the measurement configuration message to the electronic device, if it does not receive the measurement report message sent by the electronic device within the timeout period, it will send a redirection message to the first cell to trigger the electronic device to perform a redirection process.

[0255] Step 606: The first cell sends a redirection message to the electronic device.

[0256] This redirection message is used to instruct the electronic device to redirect to an inter-system neighbor cell. Exemplarily, this redirection message can be an RRC connection release message carrying a redirected carrier information cell. This redirected carrier information cell can contain a redirected frequency point.

[0257] Step 607: After receiving the redirection message, the electronic device accesses a second cell.

[0258] 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.

[0259] 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 redirection frequency point. If there is no suitable second cell on the redirection frequency point, the electronic device can expand the search range, that is, it can search for the second cells corresponding to other frequency points to search for a relatively good second cell that may exist and then access it.

[0260] In the embodiments of the present application, after the electronic device receives the measurement configuration message sent by the first cell, if the signal quality of the measured second cells 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 execute 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. If the electronic device successfully accesses this second cell, it can continue to execute 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 a call through the second network.

[0261] In some embodiments, the operation of the electronic device accessing a second cell may include the following two methods:

[0262] The first method: The electronic device accesses a second cell whose signal strength is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold.

[0263] Since the signal strength of this second cell is relatively good and the signal quality is also relatively good, the success rate of the electronic device accessing this second cell is relatively high.

[0264] The second method: The electronic device accesses a second cell belonging to a preset cell type.

[0265] The preset cell type can be set in advance. The preset cell type is a cell type with a relatively high access success rate. Therefore, the success rate of the electronic device accessing the second cell belonging to the preset cell type is relatively high.

[0266] For example, the preset cell type may be a high - speed rail cell. Of course, the preset cell type may also be other cell types, which are not limited in the embodiments of the present application. Among them, high - speed rail cells are some cells established along high - speed rail lines, mainly used to solve the problem of poor signal of electronic devices of passengers on the high - speed rail during its travel. Since high - speed rail cells are generally dedicated, they are not overly congested. In addition, some operators isolate high - speed rail cells from non - high - speed rail cells. Therefore, there are few problems when accessing high - speed rail cells. Thus, during the travel of the high - speed rail, the success rate of the electronic devices of passengers on the high - speed rail when accessing high - speed rail cells is relatively high, and the network experience after accessing high - speed rail cells is also relatively good.

[0267] Optionally, the system message broadcast by the second cell may carry the cell type of the second cell. In this case, the electronic device can parse the system message of the second cell to obtain the cell type of the second cell.

[0268] In some embodiments, in step 607, the electronic device may use a random access method (including but not limited to a competitive random access method) to access a second cell.

[0269] 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 is in the RRC idle state. After the electronic device is in the RRC idle state, after searching for a suitable second cell, it will camp on this second cell and attempt to access this second cell. Since the cell on which the electronic device camps has changed, a TAU process will be triggered. In the TAU process, the electronic device will access this second cell and perform TAU.

[0270] Next, in combination with Figure 7 an exemplary description of a possible implementation manner for the electronic device to access this second cell will be given.

[0271] Assume that the second cell is a 4G cell. Then, the process of the electronic device accessing a 4G cell in step 607 involves the interaction among the electronic device, the eNB of this 4G cell, and the EPC, as specifically described in the following Figure 7 embodiment.

[0272] Figure 7 is a schematic diagram of a cell access process provided by an embodiment of the present application. Refer to Figure 7 and this cell access process may include the following steps 701 to step 708.

[0273] Step 701: The electronic device sends a random access prefix to the eNB of this 4G cell.

[0274] Exemplarily, the electronic device may carry the random access prefix in the MSG1 message and send it to the eNB.

[0275] Step 702: After receiving the random access prefix, the eNB sends a random access response message to the electronic device.

[0276] Exemplarily, the random access response message can also be referred to as an MSG2 message.

[0277] Step 703: After receiving the random access response message, the electronic device sends an RRC connection request message to the eNB.

[0278] Exemplarily, the RRC connection request message can also be referred to as an MSG3 message.

[0279] Step 704: After receiving the RRC connection request message, the eNB sends an RRC connection setup message to the electronic device.

[0280] Exemplarily, the RRC connection setup message can also be referred to as an MSG4 message. The RRC connection setup message can carry SRB1 configuration information.

[0281] It should be noted that after receiving the RRC connection setup message sent by the eNB, the electronic device has actually accessed the 4G cell. However, since the cell where the electronic device camps 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 the EPC) of its current TA. Therefore, after receiving the RRC connection setup message, the electronic device will also execute the following steps 705 to 710 to perform a TAU.

[0282] Step 705: After receiving the RRC connection setup message, the electronic device sends an RRC connection setup complete message to the eNB, and the RRC connection setup complete message contains a TAU request message.

[0283] After receiving the RRC connection setup message, the electronic device can configure SRB1 according to the SRB1 configuration information in the RRC connection setup message, and then can send the RRC connection setup complete message to the eNB through SRB1.

[0284] Exemplarily, the TAU request message can include the TAI of the TA where the electronic device is currently located.

[0285] Step 706: After receiving the RRC connection setup complete message, the eNB sends an initial UE message to the EPC, and the initial UE message contains a TAU request message.

[0286] Step 707: After receiving the initial UE message, the EPC sends a downlink NAS transport message to the eNB, and the downlink NAS transport message contains a TAU acceptance message.

[0287] 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.

[0288] 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 transport message containing a TAU acceptance message to the eNB.

[0289] Step 708: After receiving the downlink NAS transport message, the eNB sends a downlink information transport message to the electronic device, and the downlink information transport message contains a TAU acceptance message.

[0290] Step 709: After receiving the downlink information transport message, the electronic device sends an uplink information transport message to the eNB, and the uplink information transport message contains a TAU completion message.

[0291] Since the electronic device triggers the TAU procedure in the RRC idle state, in step 709, the electronic device may send the uplink information transport message to the eNB through SRB1.

[0292] Step 710: After receiving the uplink information transport message, the eNB sends an uplink NAS transport message to the EPC, and the uplink NAS transport message contains a TAU completion message.

[0293] After the EPC receives the TAU completion message, the TAU procedure is completed.

[0294] Thus, the electronic device has completed the cell access procedure and the related TAU procedure. After that, the electronic device may continue to perform other operations to complete the EPSFB procedure. After the electronic device completes the EPSFB procedure, that is, successfully falls back from the 5G network to the 4G network, then the electronic device may make a call through the 4G network.

[0295] It should be noted that the embodiments of the present application only use the above Figure 7 embodiments as examples to exemplarily illustrate the process of the electronic device accessing a second cell in step 607. The above Figure 7 embodiments do not limit the embodiments of the present application. The electronic device may also access the second cell through other methods different from the above Figure 7 embodiments, and the embodiments of the present application do not limit this.

[0296] It should be noted that the above Figure 6The embodiments are only exemplified by the call scenario triggering the network fallback process. In actual applications, the network fallback processes triggered by other scenarios can also be implemented by the cell access method provided in the embodiments of the present application. That is to say, in the embodiments of the present application, when the electronic device accesses the first cell in step 601, not only can the subsequent steps 603 to 607 of the network fallback process be triggered in the scenario described in step 602, but also the subsequent steps 603 to 607 of the network fallback process can be triggered in other scenarios with network fallback requirements. The cell access method provided in the embodiments of the present application can improve the success rate of the network fallback processes triggered in various scenarios.

[0297] In the embodiments of the present application, after receiving the measurement configuration message sent by the first cell, the electronic device can not only measure the signal strength of the second cell, but also measure 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 execute 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, thus improving the success rate of the network fallback process.

[0298] In a possible implementation manner, the cell access method provided in the embodiments of the present application is used to solve the problem that in step 207 of the above Figure 2 embodiment, the electronic device attempts to access the 4G cell A but fails. Next, a detailed description will be given in the following Figure 8 embodiment.

[0299] Figure 8 is a flowchart of a cell access method provided in the embodiments of the present application. Refer to Figure 8 and the method includes the following steps:

[0300] Step 801: The electronic device accesses the first cell.

[0301] The operation of step 801 is similar to the operation of step 301 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0302] 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.

[0303] The operation of step 802 is similar to the operation of step 302 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0304] 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 making 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 is triggered so that the electronic device can make subsequent calls through the second network. In the embodiments of the present application, the network fallback process may at least include the following steps 803 to 809.

[0305] Step 803: The first cell sends a measurement configuration message to the electronic device.

[0306] The operation of step 803 is similar to the operation of step 303 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0307] Step 804: After receiving the measurement configuration message, the electronic device measures the signal strength of the second cell.

[0308] The operation of step 804 is similar to the operation in which the electronic device measures the signal strength of the second cell in step 304 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0309] Step 805: The electronic device determines whether there are multiple specific cells in the measured second cell; if there are multiple specific cells in the measured second cell, step 806 is executed.

[0310] The multiple specific cells may be some second cells in the second cell measured by the electronic device with relatively high and similar signal strengths. The signal strength of each specific cell in the multiple specific cells may be 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.

[0311] The preset difference can be set in advance. The preset difference can be set relatively small. If the difference in signal strength between two second cells is less than the preset difference, it means that the signal strengths of these two second cells are relatively close; if the difference in signal strength between two second cells is greater than or equal to the preset difference, it means that the signal strengths of these two second cells are relatively different.

[0312] It should be noted that if there are no multiple specific cells in the measured second cell, then for any one of the measured second cells, the electronic device may report the signal strength of this second cell to the first cell when the signal strength of this second cell is higher than the signal strength threshold, that is, send a measurement report message including the signal strength of this second cell to the first cell.

[0313] If there are the multiple specific cells in the measured second cell, then for any other second cell in the measured second cell except the multiple specific cells, the electronic device may report the signal strength of this second cell to the first cell when the signal strength of this second cell is higher than the signal strength threshold, that is, send a measurement report message including the signal strength of this 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 moving state, and then determine whether to report the signal strength of the multiple specific cells accordingly, as described in step 806 below.

[0314] Step 806: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in a preset moving state, then execute step 807.

[0315] The preset moving state can be set in advance. Exemplarily, the preset moving state can be a high-speed moving state.

[0316] Optionally, the operation for the electronic device to determine whether the electronic device is in a preset moving state can be: determining that the electronic device is in a preset moving state when the moving speed of the electronic device is greater than or equal to the moving speed threshold, and determining that the electronic device is not in a preset moving state when the moving speed of the electronic device is less than the moving speed threshold.

[0317] Wherein, the moving speed threshold can be set in advance. The moving speed threshold can be set to be relatively large. For example, the moving speed threshold can be 100 km / h (kilometer per hour), 150 km / h, 200 km / h, etc., and the embodiments of the present application do not limit this.

[0318] It should be noted that if the electronic device is not in a preset moving state, then for any one of the multiple specific cells, the electronic device may 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.

[0319] If the electronic device is in a preset moving state, then the signal strength of the second cell measured by the electronic device will change relatively fast. 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 among the multiple specific cells, but will soon move to other positions. That is to say, 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 will soon become stronger, and the signal strength of the specific cell located behind the moving direction of the electronic device will soon become weaker.

[0320] In this case, if the signal strengths of the multiple specific cells are directly reported to the first cell, since the signal strengths of the multiple specific cells are the same or similar, the second cell selected by the first cell from them may be a second cell located behind the moving direction 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 then it is very likely that the electronic device will encounter an access failure problem when attempting to access this second cell subsequently.

[0321] Therefore, in order to ensure the success rate when the electronic device accesses the second cell subsequently, in this case, the signal strengths of the multiple specific cells are not reported to the first cell first, but the signal strengths of the multiple specific cells are re-measured after a second preset duration. Since the second preset duration has passed, the signal strengths of the multiple specific cells that were the same or similar before have changed. Among them, the signal strength of the specific cell located in front of the moving direction of the electronic device becomes stronger, while the signal strength of the specific cell located behind the moving direction of the electronic device becomes weaker. As described in step 807 below.

[0322] Step 807: The electronic device re-measures the signal strengths of the multiple specific cells after the second preset duration.

[0323] The second preset duration can be set in advance. The second preset duration can be set to be relatively small. For example, the second preset duration can be 1 second, 2 seconds, etc. The embodiments of the present application do not limit this. It should be noted that the first cell will set a timeout time after sending the measurement configuration message, and the second preset duration is less than this timeout time.

[0324] For any one of 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 is not reported to the first cell, that is, a measurement report message including the signal strength of this specific cell is not sent to the first cell.

[0325] If the signal strength of this specific cell measured this time increases compared with the previous measurement, the signal strength of this specific cell measured this time is reported to the first cell, that is, a measurement report message including the signal strength of this specific cell is sent to the first cell, as described in step 808 below.

[0326] Step 808: The electronic device sends a measurement report message to the first cell.

[0327] The measurement report message includes the signal strengths of the specific cells with increased signal strengths among the multiple specific cells, and further may include the cell identifiers (including but not limited to PCI) of the specific cells.

[0328] For example, if there is only one specific cell with an increased signal strength among the multiple specific cells, the electronic device may send a measurement report message to the first cell. This measurement report message may include the signal strength of this specific cell, and may further include the cell identifier of this specific cell, etc.

[0329] For example, if there are at least two specific cells with increased signal strength among the multiple specific cells, the electronic device may send a measurement report message to the first cell. This measurement report message may include the signal strength of each of the at least two specific cells, and may further include the cell identifier of each of the at least two specific cells, etc.; or, the electronic device may send at least two measurement report messages to the first cell. Each measurement report message of the at least two measurement report messages may include the signal strength of one specific cell among the at least two specific cells, and may further include the cell identifier of this specific cell, etc.; or, the electronic device may send at least one measurement report message to the first cell. Each measurement report message of the at least one measurement report message may include the signal strength of at least one specific cell among the at least two specific cells, and may further include the cell identifier of each of the at least one specific cells, etc.

[0330] After receiving the measurement report message sent by the electronic device, the first cell may select a second cell according to the signal strength of the second cell included in the measurement report message sent by the electronic device. For example, it may select a second cell with the highest signal strength. Then the first cell may instruct the electronic device to switch to this second cell.

[0331] In the embodiments of the present application, when the electronic device is in a preset moving state, in the case of finding that there are multiple specific cells with relatively high and similar signal strengths, it will delay reporting the signal strength of the specific cell with increased signal strength to the first cell until the signal strengths of the multiple specific cells change. Since the signal strength of the second cell located in front of the moving direction of the electronic device will increase as the electronic device moves 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 probably the second cell located in front of the moving direction of the electronic device. In this case, the second cell selected by the first cell according to the signal strength of the second cell reported by the electronic device is probably the second cell located in front of the moving direction of the electronic device.

[0332] Step 809: The first cell sends a handover command to the electronic device.

[0333] The operation of step 809 is similar to the operation of step 307 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this again.

[0334] Step 810: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0335] The operation in Step 810 is similar to the operation in Step 308 in the above Figure 3 embodiment, and details are not described herein again in the embodiments of the present application.

[0336] Since the second cell indicated by the handover command is likely to be a second cell in front of the moving direction of the electronic device, as the electronic device moves, the signal strength of this second cell will become stronger and stronger. Therefore, when the electronic device attempts to access this second cell, it is likely to succeed.

[0337] If the electronic device successfully accesses this 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 a call through the second network.

[0338] Optionally, a possible implementation manner for the electronic device to access this second cell may be the manner described in the above Figure 5 embodiment, and details are not described herein again in the embodiments of the present application.

[0339] It should be noted that the above Figure 8 embodiment only takes the call scenario triggering the network fallback process as an example for illustrative purposes. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiments of the present application. That is to say, in the embodiments of the present application, when the electronic device accesses the first cell in Step 801, not only can the network fallback process described in Steps 803 to 810 be triggered in the scenario described in Step 802, but also the network fallback process described in Steps 803 to 810 can be triggered in other scenarios with network fallback requirements. The cell access method provided in the embodiments of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0340] In an embodiment of the present application, after the electronic device receives a measurement configuration message sent by a first cell, it measures the signal strength of a second cell. If there are multiple specific cells in the measured second cell with relatively high and similar or close signal strengths, when the electronic device is in a preset moving state, the signal strengths of these multiple specific cells are re-measured after a second preset duration. After re-measuring the signal strengths of these multiple specific cells, a measurement report message including the signal strengths of the specific cells with increased signal strength is sent to the first cell. Subsequently, the electronic device can receive a handover command sent by the first cell. Since the second cell indicated by this handover command is most likely a second cell located in front of the moving direction of the electronic device, as the electronic device moves, the signal strength of this second cell will become stronger and stronger. Therefore, the success rate of the electronic device when accessing this second cell is relatively high, thus improving the success rate of the network fallback process.

[0341] In some embodiments, the three possible methods provided in the above Figure 3 embodiments to Figure 8 embodiments can be flexibly combined to better improve the success rate of the network fallback process.

[0342] Next, a possible combination method of the above Figure 3 embodiment and Figure 6 embodiment will be explained in detail.

[0343] Figure 9 is a flowchart of a cell access method provided by an embodiment of the present application. Refer to Figure 9 , the method includes the following steps:

[0344] Step 901: The electronic device accesses a first cell.

[0345] The operation of step 901 is similar to the operation of step 301 in the above Figure 3 embodiment, and details are not described again in the embodiments of the present application.

[0346] 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.

[0347] The operation of step 902 is similar to the operation of step 302 in the above Figure 3 embodiment, and details are not described again in the embodiments of the present application.

[0348] Step 903: The first cell sends a measurement configuration message to the electronic device.

[0349] The operation of step 903 is similar to the operation of step 303 in the above Figure 3 embodiment, and details are not described again in the embodiments of the present application.

[0350] Step 904: After the electronic device receives the measurement configuration message, it measures the signal strength and signal quality of the second cell.

[0351] The operation of step 904 is similar to the operation of step 304 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0352] Step 905: After the electronic device receives the measurement configuration message, every first preset duration, it processes the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within the first preset duration, to obtain the target signal strength of the one or more second cells.

[0353] The operation of step 905 is similar to the operation of step 305 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0354] Step 906: For any one of the one or more second cells, the electronic device determines whether the target signal strength of this second cell is higher than the signal strength threshold and whether the signal quality of this second cell is not lower than the signal quality threshold.

[0355] If the target signal strength of this second cell is higher than the signal strength threshold and the signal quality of this second cell is not lower than the signal quality threshold, then perform the following steps 907 to 909. If the target signal strength of this second cell is not higher than the signal strength threshold, and / or, the signal quality of this second cell is lower than the signal quality threshold, then perform the following steps 910 to 912.

[0356] Step 907: If the target signal strength of this second cell is higher than the signal strength threshold and the signal quality of this second cell is not lower than the signal quality threshold, then the electronic device sends a measurement report message including the target signal strength of this second cell to the first cell.

[0357] It should be noted that after the electronic device receives the measurement configuration message, every first preset duration, it can not only obtain the target signal strength of one or more second cells measured within the first preset duration, but also send a measurement report message to the first cell when there is a second cell among the one or more second cells whose target signal strength is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold. Exemplarily, a measurement report message can include only the target signal strength of one second cell, and further can include the cell identifier of this second cell, etc.; or, a measurement report message can include the target signal strengths of at least two second cells, and further can include the cell identifier of each of the at least two second cells, etc.

[0358] The operation of the electronic device sending a measurement report message to the first cell in step 907 is similar to the operation of the electronic device sending a measurement report message to the first cell in step 306 in the above Figure 3 embodiment, and details thereof are not described herein again in the embodiments of the present application.

[0359] Step 908: The first cell sends a handover command to the electronic device.

[0360] The operation of step 908 is similar to the operation of Figure 3 step 307 in the above embodiment, and details thereof are not described herein again in the embodiments of the present application.

[0361] Step 909: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0362] The operation of step 909 is similar to the operation of Figure 3 step 308 in the above embodiment, and details thereof are not described herein again in the embodiments of the present application.

[0363] Step 910: If the target signal strength of this second cell is not higher than the signal strength threshold, and / or the signal quality of this 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 this second cell to the first cell.

[0364] It should be noted that if, after receiving the measurement configuration message, the electronic device measures that the signal quality of all second cells is lower than the signal quality threshold, then in the embodiments of the present application, the electronic device will never report the target signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, will never send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it does not receive the measurement report message sent by the electronic device within the timeout period, it will send a redirection message to the first cell to trigger the electronic device to perform a redirection process.

[0365] 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 Figure 6 the electronic device not sending a measurement report message to the first cell in step 605 in the above embodiment, and details thereof are not described herein again in the embodiments of the present application.

[0366] Step 911: The first cell sends a redirection message to the electronic device.

[0367] The operation of step 911 is similar to the operation of Figure 6 step 606 in the above embodiment, and details thereof are not described herein again in the embodiments of the present application.

[0368] Step 912: After receiving the redirection message, the electronic device accesses a second cell.

[0369] The operation of step 912 is similar to that of step 607 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0370] The above Figure 9 technical effects obtained by the embodiment are similar to those obtained by the corresponding technical means in the above Figure 3 embodiment and Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0371] It should be noted that the above Figure 9 embodiment only takes the call scenario triggering the network fallback process as an example for illustrative description. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided in the embodiments of the present application. That is to say, in the case where the electronic device accesses the first cell in step 901 in the embodiments of the present application, not only can the network fallback process described in steps 903 to 912 be triggered in the scenario described in step 902, but also the network fallback process described in steps 903 to 912 can be triggered in other scenarios where there is a network fallback requirement. The cell access method provided in the embodiments of the present application can improve the success rate of the network fallback process triggered in various scenarios.

[0372] Next, a possible combination manner of the above Figure 3 embodiment and Figure 8 embodiment will be explained in detail.

[0373] Figure 10 is a flowchart of a cell access method provided in the embodiments of the present application. Refer to Figure 10 , the method includes the following steps:

[0374] Step 1001: The electronic device accesses the first cell.

[0375] The operation of step 1001 is similar to that of step 301 in the above Figure 3 embodiment, and details are not described herein again in the embodiments of the present application.

[0376] 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.

[0377] The operation of step 1002 is similar to that of step 302 in the above Figure 3 embodiment, and details are not described herein again in the embodiments of the present application.

[0378] Step 1003: The first cell sends a measurement configuration message to the electronic device.

[0379] The operation of step 1003 is similar to that of step 303 in the above Figure 3 embodiment, and details are not described herein again in the embodiments of the present application.

[0380] Step 1004: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0381] The operation of step 1004 is similar to that of step 304 in the above Figure 3 embodiment, and details are not described herein again in the embodiments of the present application.

[0382] Step 1005: After receiving the measurement configuration message, the electronic device processes the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within the first preset time interval at every first preset time interval, so as to obtain the target signal strength of the one or more second cells.

[0383] The operation of step 1005 is similar to that of step 305 in the above Figure 3 embodiment, and details are not described herein again in the embodiments of the present application.

[0384] Step 1006: The electronic device determines whether there are multiple specific cells among the one or more second cells; if there are the multiple specific cells among the one or more second cells, step 1007 is executed.

[0385] The multiple specific cells are some second cells with relatively high target signal strength and the same or similar target signal strength 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 between the target signal strengths of any two specific cells among the multiple specific cells is less than the preset difference.

[0386] It should be noted that if there are no such multiple specific cells among the one or more second cells, for any one of the one or more second cells, the electronic device may report the target signal strength of this second cell to the first cell when the target signal strength of this second cell is higher than the signal strength threshold, that is, send a measurement report message including the target signal strength of this second cell to the first cell.

[0387] If there are the multiple specific cells 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 this second cell to the first cell when the target signal strength of this second cell is higher than the signal strength threshold, that is, send a measurement report message including the target signal strength of this 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 moving state, and then determine whether to report the target signal strength of the multiple specific cells accordingly, as described in step 1007 below.

[0388] Step 1007: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in a preset moving state, step 1008 is executed.

[0389] It should be noted that if the electronic device is not in a preset moving state, then for any one of the multiple specific cells, the electronic device may report the target signal strength of this specific cell to the first cell, that is, send a measurement report message including the target signal strength of this specific cell to the first cell. If the electronic device is in a preset moving state, step 1008 below is executed.

[0390] Step 1008: The electronic device re-measures the signal strength and signal quality of the multiple specific cells after a second preset duration, and 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.

[0391] In step 1008, the operation of the electronic device processing 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 is the same as that in Figure 3 In step 305 of the embodiment above, the operation of the electronic device processing 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 duration to obtain the target signal strength of the one or more second cells is similar, and this is not elaborated in this embodiment of the present application.

[0392] For any one of 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 is not reported to the first cell, that is, a measurement report message including the target signal strength of this specific cell is not sent to the first cell.

[0393] If the target signal strength of this specific cell measured this time increases compared with the previous measurement, report the target signal strength of this specific cell to the first cell, that is, send a measurement report message including the target signal strength of this specific cell to the first cell, as specifically described in step 1009 below.

[0394] Step 1009: The electronic device sends a measurement report message to the first cell.

[0395] 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 the cell identifier (including but not limited to PCI) of the specific cell.

[0396] The operation of step 1009 is similar to the operation of step 808 in the above Figure 8 embodiment, and this application embodiment will not elaborate on it here.

[0397] Step 1010: The first cell sends a handover command to the electronic device.

[0398] The operation of step 1010 is similar to the operation of step 307 in the above Figure 3 embodiment, and this application embodiment will not elaborate on it here.

[0399] Step 1011: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0400] The operation of step 1011 is similar to the operation of step 308 in the above Figure 3 embodiment, and this application embodiment will not elaborate on it here.

[0401] The above Figure 10 technical effects obtained by the embodiment are similar to the technical effects obtained by the corresponding technical means in the above Figure 3 embodiment and Figure 8 embodiment, and this application embodiment will not elaborate on it here.

[0402] It should be noted that the above Figure 10 embodiment only takes the call scenario triggering the network fallback process as an example for illustrative purposes. In actual applications, the network fallback process triggered by other scenarios can also be implemented by the cell access method provided by this application embodiment. That is to say, in the case where the electronic device accesses the first cell in step 1001 of this application embodiment, not only can the network fallback process described in steps 1003 to 1011 be triggered in the scenario described in step 1002, but also the network fallback process described in steps 1003 to 1011 can be triggered in other scenarios with network fallback requirements. The cell access method provided by this application embodiment can improve the success rate of the network fallback process triggered in various scenarios.

[0403] Next, a possible combination of the above Figure 6 embodiments and Figure 8 embodiments will be explained in detail.

[0404] Figure 11 is a flowchart of a cell access method provided by an embodiment of the present application. Refer to Figure 11 , the method includes the following steps:

[0405] Step 1101: The electronic device accesses the first cell.

[0406] The operation of step 1101 is similar to that of step 601 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0407] 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.

[0408] The operation of step 1102 is similar to that of step 602 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0409] Step 1103: The first cell sends a measurement configuration message to the electronic device.

[0410] The operation of step 1103 is similar to that of step 603 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0411] Step 1104: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0412] The operation of step 1104 is similar to that of step 604 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0413] Step 1105: The electronic device determines whether there are multiple specific cells in the measured second cell; if there are multiple specific cells in the measured second cell, step 1106 is executed.

[0414] The multiple specific cells are some second cells in the second cell measured by the electronic device with relatively high and equal or similar signal strengths. 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 the preset difference.

[0415] It should be noted that if the multiple specific cells do not exist in the measured second cell, then for any one of the measured second cells, the electronic device can report the signal strength of this second cell to the first cell when the signal strength of this second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold, that is, send a measurement report message including the signal strength of this second cell to the first cell. When the signal strength of this second cell is not higher than the signal strength threshold, and / or, the signal quality of this second cell is lower than the signal quality threshold, the signal strength of this second cell is not reported to the first cell, that is, a measurement report message including the signal strength of this second cell is not sent to the first cell.

[0416] If the multiple specific cells exist in the measured second cell, then for any other second cell in the measured second cell except the multiple specific cells, the electronic device can report the signal strength of this second cell to the first cell when the signal strength of this second cell is higher than the signal strength threshold and the signal quality is not lower than the signal quality threshold, that is, send a measurement report message including the signal strength of this second cell to the first cell; when the signal strength of this second cell is not higher than the signal strength threshold, and / or, the signal quality of this second cell is lower than the signal quality threshold, the signal strength of this second cell is not reported to the first cell, that is, a measurement report message including the signal strength of this second cell is not sent to the first cell. For the multiple specific cells, it is necessary to first determine whether the electronic device is in a preset moving state, and then determine whether to report the signal strength of the multiple specific cells accordingly, as described in step 1106 below.

[0417] Step 1106: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in a preset moving state, then step 1107 is executed.

[0418] It should be noted that if the electronic device is not in a preset moving state, then for any one of the multiple specific cells, the electronic device can report the signal strength of this specific cell to the first cell when 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; when 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, a measurement report message including the signal strength of this specific cell is not sent to the first cell.

[0419] If the electronic device is in a preset moving state, then the following step 1107 is executed.

[0420] Step 1107: The electronic device re-measures the signal strength and signal quality of the multiple specific cells after a second preset duration.

[0421] Step 1108: For any one of the multiple specific cells, the electronic device determines whether the signal strength of this specific cell increases and whether the signal quality of this specific cell is not lower than the signal quality threshold.

[0422] 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 perform the following steps 1109 to 1111; if the signal strength of this specific cell remains unchanged or decreases, and / or, the signal quality of this specific cell is lower than the signal quality threshold, then perform steps 1112 to 1114.

[0423] For any one of the multiple specific cells, if the signal strength of this specific cell measured this time remains unchanged or decreases compared to the previous measurement, then the signal strength of this specific cell is not reported to the first cell, that is, a measurement report message including the signal strength of this specific cell is not sent to the first cell, as specifically described in step 1112 below.

[0424] If the signal strength of this specific cell measured this time increases compared to the previous measurement, then when the signal quality of this specific cell is not lower than the signal quality threshold, the signal strength of this specific cell is reported to the first cell, that is, a measurement report message including the signal strength of this specific cell is sent to the first cell, as specifically described in step 1109 below; and when 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, a measurement report message including the signal strength of this specific cell is not sent to the first cell, as specifically described in step 1112 below.

[0425] Step 1109: 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 the electronic device sends a measurement report message including the signal strength of this specific cell to the first cell.

[0426] 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 above Figure 8 embodiment, and this embodiment of the present application will not elaborate on it further.

[0427] Step 1110: The first cell sends a handover command to the electronic device.

[0428] The operation of step 1110 is similar to the operation of step 809 in the above Figure 8 embodiment, and this embodiment of the present application will not elaborate on it further.

[0429] Step 1111: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0430] The operation of Step 1111 is similar to the operation of Step 810 in the above Figure 8 embodiment, and details are not described herein again in the embodiments of the present application.

[0431] Step 1112: If the signal strength of this specific cell remains unchanged or decreases, and / or the signal quality of this specific cell is lower than the signal quality threshold, the electronic device does not send a measurement report message including the signal strength of this specific cell to the first cell.

[0432] It should be noted that if, after receiving the measurement configuration message, the electronic device measures that the signal quality of all second cells is lower than the signal quality threshold, then in the embodiments of the present application, the electronic device will never report the signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will never send a measurement report message to the first cell. After the first cell sends the measurement configuration message to the electronic device, if it does not receive the measurement report message sent by the electronic device within the timeout period, it will send a redirection message to the first cell to trigger the electronic device to perform a redirection process.

[0433] The operation in Step 1112 where the electronic device does not send a measurement report message to the first cell is similar to the operation in Step 605 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0434] Step 1113: The first cell sends a redirection message to the electronic device.

[0435] The operation of Step 1113 is similar to the operation of Step 606 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0436] Step 1114: After receiving the redirection message, the electronic device accesses a second cell.

[0437] The operation of Step 1114 is similar to the operation of Step 607 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0438] The above Figure 11 The technical effects obtained by the embodiments are similar to the technical effects obtained by the corresponding technical means in the above Figure 6 embodiment and Figure 8 embodiment, and details are not described herein again in the embodiments of the present application.

[0439] It should be noted that the above Figure 11The embodiments are only exemplarily described by taking the call scenario triggering the network fallback process as an example. In actual applications, the network fallback processes triggered by other scenarios can also be implemented by the cell access method provided in the embodiments of the present application. That is to say, in the case where the electronic device accesses the first cell in step 1101 in the embodiments of the present application, the subsequent network fallback processes described in steps 1103 to 1114 can be triggered not only in the scenario described in step 1102, but also in other scenarios where there is a network fallback requirement. The cell access method provided in the embodiments of the present application can improve the success rate of the network fallback processes triggered in various scenarios.

[0440] Next, a possible combination manner of the above Figure 3 embodiment, Figure 6 embodiment and Figure 8 embodiment will be explained in detail.

[0441] Figure 12 is a flowchart of a cell access method provided in the embodiments of the present application. Refer to Figure 12 The method includes the following steps:

[0442] Step 1201: The electronic device accesses the first cell.

[0443] The operation of step 1201 is similar to the operation of step 301 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0444] 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.

[0445] The operation of step 1202 is similar to the operation of step 302 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0446] Step 1203: The first cell sends a measurement configuration message to the electronic device.

[0447] The operation of step 1203 is similar to the operation of step 303 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0448] Step 1204: After receiving the measurement configuration message, the electronic device measures the signal strength and signal quality of the second cell.

[0449] The operation of step 1204 is similar to the operation of step 304 in the above Figure 3 embodiment, and the embodiments of the present application will not elaborate on this.

[0450] Step 1205: After receiving the measurement configuration message, the electronic device processes the signal strength of 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, so as to obtain the target signal strength of the one or more second cells.

[0451] The operation of step 1205 is similar to the operation of step 305 in the above Figure 3 embodiment, and details thereof are not described herein again in the embodiments of the present application.

[0452] Step 1206: The electronic device determines whether there are multiple specific cells among the one or more second cells; if there are the multiple specific cells among the one or more second cells, step 1207 is executed.

[0453] The multiple specific cells are some second cells with relatively high and identical 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 between the target signal strengths of any two specific cells among the multiple specific cells is less than the preset difference.

[0454] It should be noted that if there are no such multiple specific cells among the one or more second cells, then for any one of the one or more second cells, the electronic device may report the target signal strength of this second cell to the first cell when the target signal strength of this second cell is higher than the signal strength threshold and the signal quality of this second cell is not lower than the signal quality threshold, that is, send a measurement report message including the target signal strength of this second cell to the first cell; when the target signal strength of this second cell is not higher than the signal strength threshold, and / or, when the signal quality of this second cell is lower than the signal quality threshold, the electronic device does not report the target signal strength of this second cell to the first cell, that is, does not send a measurement report message including the target signal strength of this second cell to the first cell.

[0455] If there are such multiple specific cells 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 this second cell to the first cell when the target signal strength of this second cell is higher than the signal strength threshold and the signal quality of this second cell is not lower than the signal quality threshold, that is, send a measurement report message including the target signal strength of this second cell to the first cell; when the target signal strength of this second cell is not higher than the signal strength threshold and / or the signal quality of this second cell is lower than the signal quality threshold, the electronic device does not report the target signal strength of this second cell to the first cell, that is, does not send a measurement report message including the target signal strength of this 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 moving state, and then determine whether to report the target signal strength of the multiple specific cells accordingly, as specifically described in step 1207 below.

[0456] Step 1207: The electronic device determines whether the electronic device is in a preset moving state. If the electronic device is in a preset moving state, then execute step 1208.

[0457] It should be noted that if the electronic device is not in a preset moving state, then for any one of the multiple specific cells, the electronic device may report the target signal strength of this specific cell to the first cell when the signal quality of this specific cell is not lower than the signal quality threshold, that is, send a measurement report message including the target signal strength of this specific cell to the first cell; when the signal quality of this specific cell is lower than the signal quality threshold, the electronic device does not report the target signal strength of this specific cell to the first cell, that is, does not send a measurement report message including the target signal strength of this specific cell to the first cell. If the electronic device is in a preset moving state, then execute step 1208 below.

[0458] Step 1208: The electronic device re-measures the signal strength and signal quality of the multiple specific cells after a second preset duration, and 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.

[0459] In step 1208, the operation of the electronic device to process 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 is the same as that in the above text Figure 3In the embodiment, in step 305, the operation of the electronic device processing the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within the first preset duration to obtain the target signal strength of the one or more second cells is similar, and this application embodiment will not elaborate on this again.

[0460] Step 1209: For any one of the multiple specific cells, the electronic device determines whether the target signal strength of this specific cell increases and whether the signal quality of this specific cell is not lower than the signal quality threshold.

[0461] If the target signal strength of this specific cell increases and the signal quality of this specific cell is not lower than the signal quality threshold, then perform the following steps 1210 to 1212; if the target signal strength of this specific cell remains unchanged or decreases, and / or, the signal quality of this specific cell is lower than the signal quality threshold, then perform steps 1213 to 1215.

[0462] For any one of the multiple specific cells, if the target signal strength of this specific cell measured this time remains unchanged or decreases compared to the previous measurement, then the target signal strength of this specific cell is not reported to the first cell, that is, a measurement report message including the target signal strength of this specific cell is not sent to the first cell, as specifically described in step 1213 below.

[0463] If the target signal strength of this specific cell measured this time increases compared to the previous measurement, then the target signal strength of this specific cell is reported to the first cell when 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 specifically described in step 1210 below; and the target signal strength of this specific cell is not reported to the first cell when the signal quality of this specific cell is lower than the signal quality threshold, that is, a measurement report message including the target signal strength of this specific cell is not sent to the first cell, as specifically described in step 1213 below.

[0464] Step 1210: If the target signal strength of this specific cell increases and the signal quality of this specific cell is not lower than the signal quality threshold, then the electronic device sends a measurement report message including the target signal strength of this specific cell to the first cell.

[0465] The operation of the electronic device sending a measurement report message to the first cell in step 1210 is similar to Figure 8 the operation of the electronic device sending a measurement report message to the first cell in step 808 in the above embodiment, and this application embodiment will not elaborate on this again.

[0466] Step 1211: The first cell sends a handover command to the electronic device.

[0467] The operation of step 1211 is similar to that of step 809 in the above Figure 8 embodiment, and details are not described herein again in the embodiments of the present application.

[0468] Step 1212: After receiving the handover command, the electronic device accesses a second cell indicated by the handover command.

[0469] The operation of step 1212 is similar to that of step 810 in the above Figure 8 embodiment, and details are not described herein again in the embodiments of the present application.

[0470] Step 1213: If the target signal strength of this specific cell remains unchanged or decreases, and / or the signal quality of this 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 this specific cell to the first cell.

[0471] It should be noted that if, after receiving the measurement configuration message, the electronic device measures that the signal quality of all second cells is lower than the signal quality threshold, then in the embodiments of the present application, the electronic device will never report the target signal strength of any second cell to the first cell after receiving the measurement configuration message, that is, it will never send a measurement report message to the first cell. After sending the measurement configuration message to the electronic device, if the first cell does not receive the measurement report message sent by the electronic device within the timeout period, it will send a redirection message to the first cell to trigger the electronic device to perform a redirection process.

[0472] The operation in step 1213 where the electronic device does not send a measurement report message to the first cell is similar to the Figure 6 operation in step 605 in the above embodiment where the electronic device does not send a measurement report message to the first cell, and details are not described herein again in the embodiments of the present application.

[0473] Step 1214: The first cell sends a redirection message to the electronic device.

[0474] The operation of step 1214 is similar to that of step 606 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0475] Step 1215: After receiving the redirection message, the electronic device accesses a second cell.

[0476] The operation of step 1215 is similar to that of step 607 in the above Figure 6 embodiment, and details are not described herein again in the embodiments of the present application.

[0477] The above Figure 12The technical effects obtained by the embodiment are similar to those of the above Figure 3 Example Figure 6 Examples and Figure 8 The technical effects obtained by the corresponding technical means in the embodiments are similar, and the embodiments of the present application will not be repeated here.

[0478] It should be noted that the above Figure 12 The embodiment is only an example of an exemplary description of the 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, not only can the network fallback process described in subsequent steps 1203 to 1215 be triggered in the scenario described in step 1202, but also the network fallback process described in subsequent steps 1203 to 1215 can 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.

[0479] In a possible implementation, the cell access method provided in the embodiment of the present application is used to solve the above Figure 2 In step 211 of the embodiment, after the electronic device sends the RRC connection reestablishment completion message to 4G cell B, the electronic device waits for too long. Figure 13 Examples and Figure 14 This is described in detail in the examples.

[0480] It should be noted that Figure 13 Example or Figure 14 The embodiment can be executed when the electronic device triggers the RLF process. Figure 2 In the embodiment, when the electronic device triggers the RLF process in step 208, the following steps may be performed: Figure 13 Example or Figure 14 Embodiment. Alternatively, in the above Figure 3 In the embodiment, when the electronic device fails to access a second cell in step 308, the RLF process may be triggered, and then the following steps may be performed: Figure 13 Example or Figure 14 Embodiment. Alternatively, in the above Figure 6 In the embodiment, when the electronic device fails to access a second cell in step 607, the RLF process may be triggered, and then the following steps may be performed: Figure 13 Example or Figure 14 Embodiment. Alternatively, in the above Figure 8 In the embodiment, when the electronic device fails to access a second cell in step 809, the RLF process may be triggered, and then the following steps may be performed: Figure 13 Example orFigure 14 Example. Similarly, in the above Figure 9 example, when the electronic device fails to access a second cell in step 909 or step 912, an RLF process can be triggered, and then the following Figure 13 example or Figure 14 example can be executed. Or, in the above Figure 10 example, when the electronic device fails to access a second cell in step 1011, an RLF process can be triggered, and then the following Figure 13 example or Figure 14 example can be executed. Or, in the above Figure 11 example, when the electronic device fails to access a second cell in step 1111 or step 1114, an RLF process can be triggered, and then the following Figure 13 example or Figure 14 example can be executed. Or, in the above Figure 12 example, when the electronic device fails to access a second cell in step 1212 or step 1215, an RLF process can be triggered, and then the following Figure 13 example or Figure 14 example can be executed. Of course, the electronic device can also trigger the RLF process in other cases and then execute the following Figure 13 example or Figure 14 example.

[0481] Figure 13 is a flowchart of a cell access method provided by an embodiment of the present application. Refer to Figure 13 , the method includes the following steps:

[0482] Step 1301: The electronic device triggers the RLF process.

[0483] The RLF process involves a cell selection process and an RRC connection reestablishment process, and the RRC connection reestablishment process aims to reestablish the RRC connection. After the electronic device triggers the RLF process, it can first select a cell (hereinafter referred to as the target cell), then the electronic device can camp on the target cell, and then establish an RRC connection with the target cell to access the target cell, as described in steps 1302 to 1306 below.

[0484] Exemplarily, after the electronic device receives a handover command sent by the first cell and fails to access a second cell indicated by the handover command, an RLF process can be triggered. In this case, the target cell is the second cell.

[0485] Step 1302: The electronic device sends an RRC connection reestablishment request message to the target cell.

[0486] Optionally, a reconstruction cause may be carried in the RRC connection reestablishment request message. Exemplarily, the reconstruction cause triggered by RLF may be "otherFailure".

[0487] Step 1303: After receiving the RRC connection reestablishment request message, the target cell sends an RRC connection reestablishment message to the electronic device, and the RRC connection reestablishment message carries SRB1 configuration information.

[0488] Step 1304: After receiving the RRC connection reestablishment message, the electronic device configures SRB1 according to the SRB1 configuration information.

[0489] Step 1305: The electronic device sends an RRC connection reestablishment complete message to the target cell.

[0490] Exemplarily, the electronic device may send an RRC connection reestablishment complete message to the target cell through SRB1.

[0491] After the electronic device sends an RRC connection reestablishment complete 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 the RRC connected state.

[0492] In this case, the electronic device has actually accessed the target cell. However, since the cell where the electronic device camps has changed, the electronic device still needs to perform TAU after accessing the target cell. Generally, when the electronic device is in the RRC connected state, TAU needs to be performed through SRB2. Therefore, after the electronic device sends an RRC connection reestablishment complete message to the target cell, it needs to wait for an RRC reconfiguration message sent by the target cell to configure SRB2 and DRB, and then it can perform TAU through SRB2.

[0493] In the related art, after the electronic device sends an RRC connection reestablishment complete message to the target cell, it can only wait for an RRC reconfiguration message sent by the target cell for configuring SRB2.

[0494] In the embodiment of the present application, in order to prevent the electronic device from waiting for too long after sending an RRC connection reestablishment complete message to the target cell, resulting in TAU failure and then causing problems such as failure of related network fallback processes, etc., the electronic device sets a timer after sending an RRC connection reestablishment complete message to the target cell. The duration of this timer can be set in advance, and in the embodiment of the present application, the duration of this timer is referred to as the third preset duration.

[0495] If the electronic device receives an RRC reconfiguration message sent by the target cell before the timer times out, that is, within the third preset duration after the electronic device sends an RRC connection re-establishment complete message to the target cell, the electronic device can configure SRB2 according to the SRB2 configuration information in the RRC reconfiguration message, and then perform TAU through SRB2. At this time, TAU can proceed normally, and related network fallback processes can also continue to proceed normally.

[0496] If the electronic device does not receive the RRC reconfiguration message sent by the target cell after the timer times out, that is, after the third preset duration after the electronic device sends an RRC connection re-establishment complete message to the target cell, the electronic device can perform TAU through SRB1, which is described in detail as follows.

[0497] Step 1306: If the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the target cell after the third preset duration of sending the RRC connection re-establishment complete message to the target cell, the electronic device performs TAU through SRB1.

[0498] The third preset duration can be set in advance. Optionally, the third preset duration can be set based on the principle that when the third preset duration times out, even if the electronic device does not receive the RRC reconfiguration message for configuring SRB2 sent by the network side, 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 (i.e., the 5 seconds that will cause the electronic device to receive the RRC connection release message sent by the network side), and can specifically be 2 seconds, 3 seconds, etc. The embodiments of the present application do not limit this.

[0499] In some embodiments, different user scenarios may correspond to different third preset durations. The user scenario refers to the scenario in which the user is using the electronic device, that is, what the user is doing with the electronic device. The user scenario can reflect the user's needs.

[0500] In this case, the third preset duration corresponding to the user scenario with a higher requirement for network latency can be relatively short. The third preset duration corresponding to the user scenario with a lower requirement for network latency can be relatively long. For example, if the user scenario in which the electronic device is located is a call scenario, the third preset duration can be relatively short, such as 2 seconds, 3 seconds, etc. If the user scenario in which the electronic device is located is a web browsing scenario, the third preset duration can be relatively long, such as 7 seconds, 8 seconds, etc.

[0501] In an embodiment of the present application, after the electronic device sends an RRC connection reestablishment completion message to the target cell, if it has not received an RRC reconfiguration message sent by the target cell for more than a third preset duration, it can directly perform a TAU through SRB1 when the current electronic device is in the RRC connected state (different from some existing technologies where TAU can only be performed through SRB2 when the current electronic device is in the RRC connected state). This can ensure the normal progress of the TAU, and then improve the success rate of related network fallback processes and the like.

[0502] Next, an exemplary description will be given of a possible implementation manner for the electronic device to perform a TAU through SRB1. Figure 14

[0503] Assume that the target cell is a 4G cell. Then the process for the electronic device to perform a TAU through SRB1 involves interactions among the electronic device, the eNB of the 4G cell, and the EPC, as specifically described in the following Figure 14 embodiment.

[0504] Figure 14 FIG. 14 is a schematic diagram of a TAU process provided by an embodiment of the present application. Refer to Figure 14 , this TAU process may include the following steps 1401 to 1406.

[0505] Step 1401: The electronic device sends an uplink information transmission message to the eNB of the 4G cell through SRB1, and the uplink information transmission message contains a TAU request message.

[0506] Step 1402: After receiving the uplink information transmission message, the eNB sends an uplink NAS transmission message to the EPC, and the uplink NAS transmission message contains a TAU request message.

[0507] Step 1403: After receiving the uplink NAS transmission message, the EPC sends a downlink NAS transmission message to the eNB, and the downlink NAS transmission message contains a TAU acceptance message.

[0508] 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, it will send a downlink NAS transmission message containing a TAU acceptance message to the eNB.

[0509] Step 1404: After receiving the downlink NAS transmission message, the eNB sends a downlink information transmission message to the electronic device, and the downlink information transmission message contains a TAU acceptance message.

[0510] ​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 contains a TAU completion message.

[0511] 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 contains a TAU completion message.

[0512] After the EPC receives the TAU completion message, the TAU process is completed.

[0513] In some cases, if the electronic device performs the TAU process during the EPSFB process, then after the electronic device completes the TAU process, it 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.

[0514] It should be noted that the embodiments of the present application only use the above Figure 14 embodiment as an example to exemplarily illustrate the process of the electronic device performing TAU via SRB1 in step 1306. The above Figure 14 embodiment does not limit the embodiments of the present application. The electronic device can also perform TAU via SRB1 in other ways different from the above Figure 14 embodiment. The embodiments of the present application do not make any limitations in this regard.

[0515] In some embodiments, if the electronic device receives an RRC reconfiguration message sent by the target cell within a third preset duration after sending an RRC connection reestablishment completion message to the target cell, the electronic device can configure SRB2 according to the SRB2 configuration information in the RRC reconfiguration message, and then perform TAU via SRB2. As an example, the process of the electronic device performing TAU via SRB2 is similar to the above Figure 14 embodiment, except that in steps 1401 and 1405, the electronic device sends the uplink information transmission message to the eNB via SRB2.

[0516] 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. After that, 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 complete message to the target cell. After the electronic device sends the RRC connection reestablishment complete message to the target cell, if it still does not receive the RRC reconfiguration message for configuring SRB2 sent by the target cell after exceeding the third preset duration, it performs TAU through SRB1. This can ensure the normal progress of TAU, and then improve the success rate of related network fallback processes and the like.

[0517] Figure 15 is a flowchart of a cell access method provided by an embodiment of the present application. Refer to Figure 15 , the method includes the following steps:

[0518] Step 1501: The electronic device triggers the RLF process.

[0519] The RLF process involves a cell selection process and an RRC connection reestablishment process, and the RRC connection reestablishment process aims to reestablish the RRC connection. After the electronic device triggers the RLF process, it can first select a cell (hereinafter referred to as the first target cell), then the electronic device can camp on the first target cell, and then establish an RRC connection with the first target cell to access the first target cell, as described in the following steps 1502 to 1506.

[0520] Exemplarily, after the electronic device receives the handover command sent by the first cell and fails to access a second cell indicated by the handover command, it can trigger the RLF process. In this case, the first target cell is the second cell.

[0521] Step 1502: The electronic device sends an RRC connection reestablishment request message to the first target cell.

[0522] Optionally, the RRC connection reestablishment request message may carry a reestablishment reason. Exemplarily, the reestablishment reason triggered by RLF may be "otherFailure".

[0523] Step 1503: After the first target cell receives the RRC connection reestablishment request message, it sends an RRC connection reestablishment message to the electronic device.

[0524] Exemplarily, the RRC connection reestablishment message carries SRB1 configuration information.

[0525] Step 1504: After the electronic device receives the RRC connection reestablishment message, it sends an RRC connection reestablishment complete message to the first target cell.

[0526] 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 completion message to the first target cell through SRB1.

[0527] 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.

[0528] In this case, the electronic device has actually accessed the first target cell. However, since the cell where the electronic device resides has changed, the electronic device needs to perform TAU after accessing the first target cell. Generally, the electronic device needs to perform TAU through SRB2 when in the RRC connected state. Therefore, after the electronic device sends the RRC connection reestablishment completion 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 TAU through SRB2.

[0529] 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.

[0530] In the 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, causing the RRC connection reestablishment process to fail, and then causing the failure of related network fallback processes, etc., the electronic device sets 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, and in the embodiment of the present application, the duration of the timer is referred to as a fourth preset duration.

[0531] If the electronic device receives an RRC reconfiguration message sent by the first target cell within the fourth preset time after the timer has not timed out, that is, the electronic device sends an RRC connection reestablishment completion message to the first target cell, the electronic device can configure SRB2 according to the SRB2 configuration information in the RRC reconfiguration message, and then perform TAU through SRB2. At this time, TAU can be performed normally, and its related network fallback processes can also continue to proceed normally.

[0532] However, if the electronic device expires the timer, that is, the electronic device still has not received the RRC reconfiguration message sent by the first target cell after the fourth preset time after sending the RRC connection reconstruction completion message to the first target cell, the electronic device can trigger the RLF process to trigger the cell change reconstruction, as described below.

[0533] 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 duration from sending the RRC connection reestablishment complete message to the first target cell, it triggers the RLF process.

[0534] The fourth preset duration can be set in advance. Optionally, the setting of the fourth preset duration can be based on the principle that when the fourth preset duration expires, 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. By way of example, the fourth preset duration can be less than the aforementioned 5 seconds (i.e., the 5 seconds that will cause the RRC connection release message sent by the network side to be received), and specifically can be 2 seconds, 3 seconds, etc. The embodiments of the present application do not limit this.

[0535] In some embodiments, different user scenarios may correspond to different fourth preset durations. The user scenario refers to the usage scenario of the user, that is, what the user is doing while using the electronic device. This user scenario can reflect the user's needs.

[0536] In this case, the fourth preset duration corresponding to the user scenario with a higher requirement for network latency can be relatively short. The fourth preset duration corresponding to the user scenario with a lower requirement for network latency can be relatively long. For example, if the user scenario where the electronic device is located is a call scenario, the fourth preset duration can be relatively short, such as 1 second, 2 seconds, etc. If the user scenario where the electronic device is located is a web browsing scenario, the fourth preset duration can be relatively long, such as 5 seconds, 6 seconds, etc.

[0537] After the electronic device sends the RRC connection reestablishment complete message to the first target cell, if it still does not receive the RRC reconfiguration message sent by the first target cell after exceeding the fourth preset duration, then the RRC connection reestablishment process between the electronic device and the first target cell is very likely to fail. In the embodiments of the present application, in this case, the electronic device can directly trigger the RLF process to trigger reestablishment by changing the cell. In this way, the cell can be changed as soon as possible for the RRC connection reestablishment process, avoiding the electronic device waiting meaninglessly for a long time, and then improving the success rate of related network fallback processes and the like.

[0538] Step 1506: The electronic device performs an RRC connection reestablishment process with the second target cell.

[0539] After triggering the RLF process, the electronic device can first release the RRC connection with the first target cell, then select a cell (i.e., the second target cell). After that, the electronic device can first camp on the second target cell and then establish an RRC connection with the second target cell to access the second target cell.

[0540] In some embodiments, after the electronic device receives a handover command sent by a first cell and fails to access a second cell indicated by the handover command, it may trigger an RLF process, and then may select a second cell as a first target cell and perform an RRC connection reestablishment process with the first target cell. During the process of the electronic device performing the RRC connection reestablishment process with the first target cell, if it does not receive an RRC reconfiguration message for configuring SRB2 sent by the first target cell after a fourth preset duration from sending an RRC connection reestablishment completion message to the first target cell, it triggers an RLF process, and then may continue to select a second cell as a second target cell and perform an RRC connection reestablishment process with the second target cell.

[0541] 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 this is not elaborated in the embodiments of the present application.

[0542] In some embodiments, during the process of the electronic device performing the RRC connection reestablishment process with the second target cell, if the electronic device does not receive an RRC reconfiguration message for configuring SRB2 sent by the second target cell after a fourth preset duration from sending an RRC connection reestablishment completion message to the second target cell, it may trigger an RLF process and continue to select a cell to perform an RRC connection reestablishment process.

[0543] In the embodiments of the present application, if the electronic device triggers an RLF process, it sends an RRC connection reestablishment request message to the first target cell. After that, if the electronic device receives an 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 an RRC connection reestablishment completion message to the first target cell, if it still does not receive an RRC reconfiguration message for configuring SRB2 sent by the first target cell after exceeding the fourth preset duration, the electronic device no longer continues to wait for the first target cell to send an RRC reconfiguration message, but directly triggers an RLF process to replace the cell as soon as possible to perform an RRC connection reestablishment process. In this way, it is possible to avoid the long and meaningless waiting of the electronic device in the RRC connection reestablishment process, and then improve the success rate of related network fallback processes and the like.

[0544] The electronic device involved in the embodiments of the present application is described below.

[0545] Figure 16 is a schematic structural diagram of an electronic device provided by the embodiments of the present application. Refer to Figure 16, 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, a headphone jack 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. Among them, the sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, a barometric 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.

[0546] It can be understood that the structure illustrated in the embodiments of the present application does 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 those illustrated, or combine certain components, or split certain components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0547] The processor 110 may include one or more processing units. For example, the processor 110 may include an application processor (AP), a modem (also referred to 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), etc. Among them, different processing units may be independent devices or integrated in one or more processors.

[0548] Among them, the controller may be the nerve center and command center of the electronic device 100. The controller may generate operation control signals according to the instruction operation code and timing signals to complete the control of fetching instructions and executing instructions.

[0549] A memory can also be set in the processor 110 for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can save the instructions or data that the processor 110 has just used or recycled. If the processor 110 needs to use the instruction or data again, it can be directly called from this memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0550] The wireless communication function of the electronic device 100 can be implemented through antenna 1, antenna 2, the mobile communication module 150, the wireless communication module 160, the Modem, etc.

[0551] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the electronic device 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be multiplexed to improve the utilization rate of the antennas. For example: Antenna 1 can be multiplexed as a diversity antenna for a wireless local area network. In some other embodiments, the antenna can be used in combination with a tuning switch.

[0552] The mobile communication module 150 can provide solutions for wireless communications such as 2G / 3G / 4G / 5G applied to the electronic device 100. The mobile communication module 150 can include at least one filter, switch, power amplifier, low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves through antenna 1, filter, amplify, etc. 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 through antenna 1 for radiation. In some embodiments, at least some functional modules of the mobile communication module 150 can be set in the processor 110. In some embodiments, at least some functional modules of the mobile communication module 150 and at least some modules of the processor 110 can be set in the same device.

[0553] The wireless communication module 160 may provide solutions for wireless communications applied to the electronic device 100, including wireless local area networks (WLANs) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite systems (GNSSs), frequency modulation (FM), near field communication (NFC), infrared (IR), etc. The wireless communication module 160 may be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, performs frequency modulation and filtering processing on the electromagnetic wave signals, and sends the processed signals to the processor 110. The wireless communication module 160 may also receive signals to be sent from the processor 110, perform frequency modulation and amplification on them, and convert them into electromagnetic waves through the antenna 2 for radiation.

[0554] 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, enabling electronic device 100 to communicate with a network and other devices via wireless communication technologies. The wireless communication technologies 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 technologies, etc. GNSS may include global positioning system (GPS), global navigation satellite system (GLONASS), beidou navigation satellite system (BDS), quasi-zenith satellite system (QZSS), and / or satellite based augmentation systems (SBAS).

[0555] The SIM card interface 195 is used to connect to a SIM card. The SIM card can be inserted into or removed from the SIM card interface 195 to establish contact with and separation from electronic device 100. Electronic device 100 may support one or N SIM card interfaces, where N is an integer greater than 1. The SIM card interface 195 may support Nano SIM cards, Micro SIM cards, SIM cards, etc. Multiple cards may be inserted into the same SIM card interface 195 simultaneously. The types of the multiple cards may be the same or different. The SIM card interface 195 may also be compatible with different types of SIM cards. The SIM card interface 195 may also be compatible with external memory cards. Electronic device 100 interacts with the network via the SIM card to implement functions such as calls and data communication. In some embodiments, electronic device 100 uses an eSIM, i.e., an embedded SIM card. The eSIM card can be embedded in electronic device 100 and cannot be separated from electronic device 100.

[0556] In the embodiments of the present application, an operating system runs on the above components. For example, the iOS operating system developed by Apple Inc., the Android open-source operating system developed by Google Inc., the Windows operating system developed by Microsoft Corporation, etc.

[0557] The operating system of the electronic device 100 may adopt a layered architecture, an event-driven architecture, a microkernel architecture, a microservices architecture, or a cloud architecture. In the embodiments of the present application, taking the Android system with a layered architecture as an example, the software and hardware structure of the electronic device 100 is exemplarily described. It should be noted that although the embodiments of the present application are described by taking the Android system as an example, the basic principle also applies to the electronic device 100 based on operating systems such as iOS or Windows.

[0558] Figure 17 This is a software structure block diagram of an electronic device 100 provided by the embodiments of the present application. The software structure adopts a layered architecture. The layered architecture divides the software into several layers, and each layer has a clear role and division of labor. The layers communicate with each other through software interfaces. Taking the Android system running on the AP as an example, in some embodiments, the Android system is divided into five layers, from top to bottom are the application layer, the application framework layer (Framework), Android runtime and system libraries, the hardware abstraction layer (hardware abstraction layer, HAL), and the kernel layer (Kernel).

[0559] The application layer may include a series of application packages. The application packages may include a camera, a gallery, a calendar, a call, a map, a wireless local area network (WLAN), Bluetooth, music, video, short message, etc. The application layer may also include system UI (system UI), and the system UI is used to display the interface of the electronic device 100, such as displaying the signal icon corresponding to the SIM card, displaying the call interface, etc.

[0560] The application framework layer provides application programming interfaces (application programming interface, API) and programming frameworks 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 telephone manager, a resource manager, a notification manager, etc. The telephone manager is used to provide the call function of the electronic device 100, such as the management of the call state (including connection, disconnection, etc.). The telephone manager is in Figure 17It is represented by telephony in [the context]. The application framework layer may also include a radio interface layer (RIL). The Modem can interact with telephony through the RIL.

[0561] The Modem may include a NAS layer, an RRC layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and a Physical (PHY) layer. Each of the foregoing layers may be a software module. The Modem can interact with the base station through an antenna. Optionally, the method provided in the embodiments of the present application may be implemented by the Modem.

[0562] 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.

[0563] Some embodiments of the present application provide a chip system, which is applied to an electronic device. The chip system includes at least one processor and an interface. The interface is used to receive instructions and transmit them to the at least one processor; the at least one processor runs the instructions to make the electronic device execute the above-mentioned cell access method. Among them, the chip system may be a Modem, or a system on chip (Soc) including a Modem, and the above method may be implemented by one Modem.

[0564] 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 processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may 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 may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, Digital Subscriber Line (DSL)) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that includes one or more integrated available media. The available medium may be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a Digital Versatile Disc (DVD)), or a semiconductor medium (such as a Solid State Disk (SSD)), etc.

[0565] The above are the optional embodiments provided by the present application, which are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the technical scope disclosed in the present application shall be included in the protection scope of the present application.

Claims

1. A cell access method, characterized in that, Applied to an electronic device, the method includes: Receiving a measurement configuration message sent by a first cell, the measurement configuration message being used to indicate measuring the signal strength of an inter-system neighboring cell; Measuring the signal strength and signal quality of a second cell, the second cell being an inter-system neighboring cell of the first cell; Every first preset duration, processing the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within the first preset duration to obtain the target signal strength of the one or more second cells; Sending a measurement report message to the first cell, the measurement report message including the 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 receiving a handover command sent by the first cell, accessing a second cell indicated by the handover command.

2. The method according to claim 1, wherein Before receiving the measurement configuration message sent by the first cell, it further includes: Receiving an invite message sent by the first cell; or, Sending an invite message to the first cell.

3. The method according to claim 1 or 2, characterized in that, The processing the signal strength of one or more second cells according to the signal quality of the one or more second cells measured within the first preset duration to obtain the target signal strength of the one or more second cells includes: Determining the weight corresponding to each second cell according to the signal quality of each second cell among the one or more second cells; Multiplying the signal strength of each second cell 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 the measurement report message to the first cell includes: For any one second cell among the one or more second cells, if the target signal strength of the one second cell is higher than a signal strength threshold and the signal quality is not lower than a 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 includes: If the target signal strength of the one second cell is not higher than a signal strength threshold, and / or, if the signal quality of the one second cell is lower than a signal quality threshold, not sending a measurement report message including the target signal strength of the one second cell to the first cell.

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

6. The method according to claim 5, wherein The method further includes: If there are the multiple specific cells among the one or more second cells, when the electronic device is in a preset moving state, re-measuring the signal strength and signal quality of the multiple specific cells after a second preset duration, and processing the signal strength of the multiple specific cells according to the signal quality of the multiple specific cells to obtain the target signal strength of the multiple specific cells; For any one of the multiple specific cells, if the target signal strength of the one specific cell increases, a measurement report message including the target signal strength of the one specific cell is sent to the first cell; if the target signal strength of the one specific cell remains unchanged or decreases, a measurement report message including the target signal strength of the one specific cell is not sent to the first cell.

7. The method according to claim 5, wherein The method further includes: If any of the one or more second cells is the multiple specific cells, when the electronic device is in a preset moving state, after a second preset duration, the signal strengths and signal qualities of the multiple specific cells are re-measured, and the signal strengths of the multiple specific cells are processed according to the signal qualities of the multiple specific cells to obtain the target signal strengths of the multiple specific cells; For any one of the multiple specific cells, if the target signal strength of the one specific cell increases and the signal quality is not lower than a signal quality threshold, a measurement report message including the target signal strength of the one specific cell is sent to the first cell; if the target 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 the signal quality threshold, a measurement report message including the target signal strength of the one 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 includes: If access to the one second cell fails, a radio link failure (RLF) procedure is triggered; A radio resource control (RRC) connection re-establishment request message is sent to a target cell, where the target cell is the second cell; An RRC connection re-establishment message sent by the target cell is received, and the RRC connection re-establishment message carries signaling radio bearer (SRB1) configuration information; SRB1 is configured according to the SRB1 configuration information; An RRC connection re-establishment completion message is sent to the target cell; If an RRC re-configuration message for configuring SRB2 sent by the target cell is not received after a third preset duration from sending the RRC connection re-establishment completion message, a tracking area update (TAU) is performed through SRB1.

9. The method according to any one of claims 1 to 7, characterized in that The method further includes: If access to the one second cell fails, an RLF procedure is triggered; An RRC connection re-establishment request message is sent to a first target cell, where the first target cell is the second cell; An RRC connection re-establishment message sent by the first target cell is received; An RRC connection re-establishment completion message is sent to the first target cell; If an RRC re-configuration message for configuring SRB2 sent by the first target cell is not received after a fourth preset duration from sending the RRC connection re-establishment completion message, an RLF procedure is triggered, and an RRC connection re-establishment procedure is performed with a second target cell, where the second target cell is the second cell.

10. A cell access method, characterized in that, Applied to an electronic device, the method includes: A measurement configuration message sent by a first cell is received, and the measurement configuration message is used to indicate measuring the signal strength of an inter-system neighboring cell; 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 the signal quality threshold, a measurement report message is not sent to the first cell; If a redirection message sent by the first cell is received, a second cell is accessed.

11. The method according to claim 10, wherein Said accessing a second cell includes: accessing 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, accessing a second cell belonging to a 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, it 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, and 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 includes: If the access to the second cell fails, an RLF procedure is triggered; Sending an RRC connection reestablishment request message to the 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; Configuring SRB1 according to the SRB1 configuration information; Sending an RRC connection reestablishment completion message to the target cell; If an RRC reconfiguration message for configuring SRB2 sent by the target cell is not received after a third preset duration from sending the RRC connection reestablishment completion message, a TAU is performed through the SRB1.

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

15. A cell access method, characterized in that, Applied to an electronic device, the method includes: Receiving a measurement configuration message sent by a first cell, where the measurement configuration message is used to indicate measuring the signal strength of an inter-system neighboring cell; Measuring the signal strength of a second cell, where the second cell is an inter-system neighboring cell 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 signal strength difference is less than a preset difference, and if the electronic device is in a preset moving state, the signal strength of the multiple specific cells is re-measured after a second preset duration; 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; 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, wherein Said measuring the signal strength of the second cell includes: Measure the signal strength and signal quality of the second cell; Sending the measurement report message to the first cell, including: For any one of 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, send a measurement report message including the signal strength of the one specific cell to the first cell; The method further includes: 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 the signal quality threshold, do not send a measurement report message including the signal strength of the one specific cell to the first cell.

17. The method according to claim 15 or 16, characterized in that The method further includes: If accessing the one second cell fails, trigger the RLF process; Send an RRC connection reestablishment request message to the target cell, where the target cell is the second cell; Receive the 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; Send an RRC connection reestablishment complete message to the target cell; If an RRC reconfiguration message for configuring SRB2 sent by the target cell is not received after a third preset duration of sending the RRC connection reestablishment complete message, perform TAU through SRB1.

18. The method according to claim 15 or 16, characterized in that, The method further includes: If accessing the one second cell fails, trigger the RLF process; Send an RRC connection reestablishment request message to the first target cell, where the first target cell is the second cell; Receive the RRC connection reestablishment message sent by the first target cell; Send an RRC connection reestablishment complete message to the first target cell; If an RRC reconfiguration message for configuring SRB2 sent by the first target cell is not received after a fourth preset duration of sending the RRC connection reestablishment complete message, trigger the RLF process and perform an RRC connection reestablishment process with a second target cell, where the second target cell is the second cell.

19. A cell access method, characterized in that, Applied to an electronic device, the method includes: If the RLF process is triggered, send an RRC connection reestablishment request message to the target cell; Receive the 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; Send an RRC connection reestablishment complete message to the target cell; If an RRC reconfiguration message for configuring SRB2 sent by the target cell is not received after a third preset duration of sending the RRC connection reestablishment complete message, perform TAU through SRB1.

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

21. The method according to claim 19 or 20, characterized in that, Before sending an RRC connection reestablishment request message to a target cell if an RLF procedure is triggered, the following steps are further included: Receiving a handover command sent by a first cell, where the handover command is used to indicate a handover to a second cell; Accessing the second cell; If the access to the second cell fails, triggering an RLF procedure.

22. A cell access method, characterized in that, Applied to an electronic device, the method includes: If an RLF procedure is triggered, sending an RRC connection reestablishment request message to a first target cell; Receiving an RRC connection reestablishment message sent by the first target cell; Sending an RRC connection reestablishment completion message to the first target cell; If an RRC reconfiguration message for configuring SRB2 sent by the first target cell is not received after a fourth preset duration from sending the RRC connection reestablishment completion message, triggering an RLF procedure and performing an RRC connection reestablishment procedure with a second target cell.

23. The method according to claim 22, wherein After sending the RRC connection reestablishment completion message to the first target cell, the following steps are further included: If the RRC reconfiguration message sent by the first target cell is received after the fourth preset duration from sending the RRC connection reestablishment completion message, performing a TAU.

24. The method according to claim 22 or 23, characterized in that, Before sending an RRC connection reestablishment request message to a first target cell if an RLF procedure is triggered, the following steps are further included: Receiving a handover command sent by a first cell, where the handover command is used to indicate a handover to a second cell; Accessing the second cell; If the access to the second cell fails, triggering an RLF procedure.

25. An electronic device, characterized in that, The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the method described in any one of claims 1 to 24 is implemented.

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

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