Communication method and related equipment

Abstract

The embodiment of the invention provides a communication method and related equipment. According to the communication method, once the UE cannot establish the RRC connection with the network equipment corresponding to the current resident cell in the call process, the UE can reduce the priority of the current resident cell of the UE, so that the UE can subsequently select other cells except a problem cell for residence through cell reselection, and the user experience is improved. Therefore, the problems of call drop and silent call caused by long-time residence in a problem cell are avoided.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method and related equipment. Background Art

[0002] When the user equipment (UE) is in a call state, the UE originally resides in cell A. Based on cell selection / cell reselection / cell switching, the UE can change from originally residing in cell A to residing in cell B. In the case where cell B is a problem cell, problems such as Radio Link Failure (RLF) may occur, and the UE will perform cell selection. Since the UE has previously resided in cell B and the signal strength of cell B is the highest, the UE still chooses to reside in cell B. In this case, the UE will trigger the Radio Resource Control (RRC) connection reestablishment process. Once the RRC connection establishment fails, the UE enters the idle state (i.e., idle state). In this case, the UE performs cell reselection. Since the signal strength and priority of cell B are better than other cells, the UE still selects cell B and initiates the RRC connection establishment process. Once the RRC connection establishment fails again, the UE enters the idle state again. In this case, the UE performs cell reselection again. For the same reason as above, since the signal strength and priority of cell B are better than other cells, the UE still selects cell B and initiates the RRC connection establishment process. It can be understood that since the signal strength and priority of cell B are better than other cells, the UE is very likely to always select cell B when reselecting the cell, and since cell B is a problem cell, the UE cannot successfully establish an RRC connection with cell B. This means that the process in which the UE selects cell B and the UE cannot successfully establish an RRC connection with cell B will be repeated. Once the number of cycles is too many, it may cause the UE call to end (i.e., call drop) and long-term silent calls. For example, once the time it takes for the UE to select cell B and finally successfully establish an RRC connection with cell B exceeds a certain threshold (e.g., 20 seconds), after the UE successfully establishes an RRC connection with cell B, the UE will actively send a BYE message to cell B, causing the UE call to end. In addition, since the UE is in a call state, as long as the UE has not successfully established an RRC connection with cell B, the call on the UE cannot continue, that is, the call on the UE will be silent.

[0003] Therefore, how to avoid UE dropped calls and long periods of silence in call scenarios is an urgent problem to be solved. Summary of the invention

[0004] The embodiments of the present application provide a communication method and related devices to avoid UE call dropping in a call scenario, and / or avoid or optimize the problem of long-term silent calls (such as shortening the silent call time).

[0005] In a first aspect, the present application provides a communication method. The method can be applied to a terminal device. The method may include: the terminal device resides in a first cell; the terminal device makes a call in the first cell; the terminal device selects a cell in the first cell when a first network abnormality occurs during the process of the terminal device residing in the first cell to make a call, and chooses to reside in the first cell; the terminal device starts a T301 timer and sends a first message to a first network device, the first network device is a network device corresponding to the first cell, and the first message is used to request random access; when the T301 timer times out, the terminal device reduces the carrier frequency priority of the first cell; the terminal device performs cell reselection according to the reduced carrier frequency priority of the first cell, and chooses to reside in a second cell, the second cell is different from the first cell; the terminal device establishes an RRC connection with a second network device, the second network device is a network device corresponding to the second cell; the terminal device continues the call in the second cell through the established RRC connection.

[0006] In the solution provided by the present application, when the terminal device has a first network anomaly during a call, the terminal device can select a cell. Since the signal strength of the cell where the terminal device originally resides is the largest, the terminal device continues to choose to reside in the cell and prepares to establish an RRC connection. Accordingly, the T301 timer is started. Once the T301 timer times out, it means that the terminal device has not successfully established an RRC connection. In this case, the terminal device can lower the carrier frequency priority (hereinafter referred to as priority) of the cell where the terminal device originally resides. And after lowering the priority, the cell is reselected, so as to reselect to other cells and continue to talk on the cell. In this way, the terminal device can lower the priority of the problem cell at a specific time or under certain circumstances, and reselect the cell based on the lowered priority of the problem cell, which can avoid the terminal device from always choosing to reside in the problem cell during the cell reselection process, thereby avoiding the terminal device from dropping calls in the call scenario, and / or avoiding or optimizing the problem of long-term silent calls (such as shortening the silent call time).

[0007] It can be understood that the terminal device and UE mentioned in this application have the same meaning.

[0008] In some embodiments of the present application, the first cell may be cell B. The second cell may be cell A. In this case, the first network device may be network device_2, and the second network device may be network device_1.

[0009] In some embodiments of the present application, the second cell may also be other cells except cell A and cell B.

[0010] In some embodiments of the present application, the first message may be MSG1.

[0011] In combination with the first aspect, in a possible implementation method, after the terminal device lowers the carrier frequency priority of the first cell, the terminal device performs the cell reselection, specifically including: the RRC layer in the terminal device sends a second message to the ML1 layer in the terminal device; the second message is used to instruct the ML1 layer to perform accelerated cell reselection; the ML1 layer in the terminal device receives the second message; and the terminal device performs accelerated cell reselection based on the second message.

[0012] In the solution provided by the present application, the terminal device can lower the priority of the problem cell before reselection, and after lowering the priority of the problem cell, send a message to the ML1 layer through the RRC layer to instruct the ML1 layer to accelerate the cell reselection. After receiving the message, the ML1 layer in the terminal device can perform accelerated cell reselection based on the message. This method can reduce the duration of staying in the problem cell, thereby reducing the duration of silent calls due to staying in the problem cell.

[0013] In some embodiments of the present application, the second message may be an RRC depriority request (RRC depriority request).

[0014] In combination with the first aspect, in a possible implementation manner, the accelerated cell reselection includes: a time duration for the terminal device to reside in the original cell before performing cell reselection is less than a first preset time duration.

[0015] In the solution provided by the present application, cell reselection can be accelerated by reducing the time spent in the original cell before cell reselection. This method can reduce the time required to trigger cell reselection, thereby accelerating the triggering of cell reselection.

[0016] It is understandable that the first preset duration may be the original prescribed duration mentioned later.

[0017] It is understandable that the first preset duration may be a duration specified in a relevant protocol, and specifically may be a duration configured by the network side for the terminal in accordance with the relevant protocol. In some embodiments of the present application, the first preset duration may be no greater than 1s. For example, the first preset duration may be 1s.

[0018] In combination with the first aspect, in a possible implementation, the accelerated cell reselection also includes: during the cell reselection process, the terminal device evaluates the target cell for a duration that is less than a second preset duration, and the target cell includes the second cell.

[0019] In the solution provided by the present application, cell reselection can be accelerated by reducing the time required to evaluate the target cell during the cell reselection process. This method can reduce the time required to actually perform cell reselection (i.e., actually select the cell to reside in) after starting cell reselection, thereby accelerating the cell reselection process.

[0020] It is understandable that the second preset duration may be the original evaluation duration mentioned later.

[0021] It is understandable that the second preset duration may be a duration specified in a relevant protocol, and specifically may be a duration configured by the network side for the terminal in accordance with the relevant protocol. In some embodiments of the present application, the second preset duration may be no greater than 1.28s. For example, the second preset duration may be 1.28s.

[0022] In combination with the first aspect, in a possible implementation manner, the sum of the duration of the terminal device residing in the original cell and the duration of the evaluation of the target cell is less than the duration of the T3411 timer currently used by the terminal device.

[0023] In the solution provided by the present application, the sum of the time that the terminal device resides in the original cell before performing cell reselection and the evaluation time of the target cell is less than the time of the T3411 timer currently used by the terminal device. Through this method, the terminal device can complete the cell reselection process after reducing the priority of the problem cell before the T3411 timer times out, so as to reselect to a cell other than the problem cell in time before re-triggering the TAU process, reducing the time it resides in the problem cell, thereby reducing the silent call time due to residing in the problem cell.

[0024] In some embodiments of the present application, the duration of the T3411 timer currently used may specifically be: the duration of the T3411 timer specified in the relevant protocol, that is, 10 seconds. In some embodiments of the present application, the duration of the T3411 timer currently used may specifically be: the duration of the T3411 timer optimized by the actual terminal device, for example, 2 seconds.

[0025] In combination with the first aspect, in a possible implementation method, the first network abnormality occurs during the process of the terminal device making a call in the first cell, specifically including: while the terminal device is residing in the first cell for making a call, failure to read the system message of the first cell results in a radio link failure RLF.

[0026] It is understandable that the first network abnormality that occurs during the call in the first cell may also be other network abnormalities (for example, handover failure), and details may be referred to below.

[0027] In combination with the first aspect, in a possible implementation, the first cell is one of at least one adjacent cell of the third cell; before the cell selection, the method also includes: the terminal device resides in the third cell to conduct the call; the terminal device switches from the third cell to reside in the first cell; a first network abnormality occurs during the process of the terminal device residing in the first cell to conduct the call.

[0028] In some embodiments of the present application, the third cell may be cell A, and the first cell may be cell B.

[0029] It is understandable that before the first network abnormality occurs during the process of the terminal device residing in the first cell for a call, the terminal device can be switched from other cells where it originally resides to the first cell.

[0030] In combination with the first aspect, in a possible implementation, after the terminal device switches from the third cell to reside in the first cell, the method also includes: the terminal device initiates a TAU process; after the terminal device sends the first message to the first network device, the method also includes: after the T301 timer expires, the terminal device starts the T3411 timer; the terminal device establishes an RRC connection with the second network device, specifically including: when the T3411 timer expires, the terminal device re-initializes the TAU process and establishes an RRC connection with the second network device.

[0031] In combination with the first aspect, in a possible implementation manner, among the neighboring cells of the third cell, the signal strength of the first cell is the largest, and the carrier frequency priority of the first cell is the highest.

[0032] In combination with the first aspect, in a possible implementation manner, the reduced carrier frequency priority corresponding to the first cell is equal to the minimum value of the priorities corresponding to several neighboring cells of the third cell.

[0033] In a second aspect, the present application provides a communication method. The method can be applied to a terminal device. The method may include: when the terminal device is stationed in a first cell and a second network anomaly occurs during a call, the terminal device performs a cell reselection and chooses to reside in the first cell; the terminal device starts a T300 timer and sends a first message to a first network device, the first network device is a network device corresponding to the first cell, and the first message is used to request random access; when the T300 timer times out, the terminal device reduces the carrier frequency priority of the first cell; the terminal device performs a cell reselection according to the reduced carrier frequency priority of the first cell, and chooses to reside in a second cell, the second cell is different from the first cell; the terminal device establishes an RRC connection with a second network device, the second network device is a network device corresponding to the second cell; the terminal device continues the call on the second cell through the established RRC connection.

[0034] In the solution provided by the present application, when a second network anomaly occurs during a call in a terminal device, the terminal device can reselect a cell. Since the signal strength of the cell where the terminal device originally resides is the largest, the terminal device continues to choose to reside in the cell and prepares to establish an RRC connection. Accordingly, the T300 timer is started. Once the T300 timer times out, it means that the terminal device has not successfully established an RRC connection. In this case, the terminal device can lower the carrier frequency priority (hereinafter referred to as priority) of the cell where the terminal device originally resides. And after lowering the priority, the cell is reselected, so as to achieve reselection to other cells and continue to talk in the cell. In this way, the terminal device can lower the priority of the problem cell at a specific time or under certain circumstances, and reselect the cell based on the lowered priority of the problem cell, which can avoid the terminal device from always choosing to reside in the problem cell during the cell reselection process, thereby avoiding the terminal device from dropping calls in call scenarios, and / or avoiding or optimizing the problem of long-term silent calls (such as shortening the silent call time).

[0035] In combination with the second aspect, in a possible implementation method, after the terminal device lowers the carrier frequency priority of the first cell, the terminal device performs the cell reselection, which specifically includes: the RRC layer in the terminal device sends a second message to the ML1 layer in the terminal device; the second message is used to instruct the ML1 layer to perform accelerated cell reselection; the ML1 layer in the terminal device receives the second message; and the terminal device performs accelerated cell reselection based on the second message.

[0036] In combination with the second aspect, in a possible implementation manner, the accelerated cell reselection includes: a time length of time that the terminal device resides in the original cell before performing cell reselection is less than a first preset time length.

[0037] In combination with the second aspect, in a possible implementation, the accelerated cell reselection also includes: during the cell reselection process, the terminal device evaluates the target cell for a duration that is less than a second preset duration, and the target cell includes the second cell.

[0038] In combination with the second aspect, in a possible implementation manner, the sum of the duration of the terminal device residing in the original cell and the duration of the evaluation of the target cell is less than the duration of the T3411 timer currently used by the terminal device.

[0039] In combination with the second aspect, in a possible implementation method, a second network abnormality occurs during a call in the first cell, specifically including: during a call in the first cell, the RRC layer in the terminal device notifies the NAS layer of a bottom layer failure, and determines a TAU failure based on the notification.

[0040] In combination with the second aspect, in a possible implementation, the first cell is one of at least one adjacent cell of the third cell; before performing cell reselection and choosing to reside in the first cell, the method also includes: the terminal device resides in the third cell to conduct the call; the terminal device switches from the third cell to reside in the first cell; a first network abnormality occurs during the process of the terminal device residing in the first cell to conduct the call, and the terminal device performs cell selection and chooses to reside in the second cell; the terminal device starts the T301 timer and sends the first message to the first network device; when the T301 timer times out, the RRC layer in the terminal device notifies the NAS layer that a bottom-level failure has occurred.

[0041] In combination with the second aspect, in a possible implementation, after the terminal device switches from the third cell to reside in the first cell, the method further includes: the terminal device initiates a TAU process; the terminal device starts the T301 timer and sends the first message to the first network device, the method further includes: when the T301 timer times out, the terminal device starts the T3411 timer; the terminal device starts the T300 timer, specifically including: when the T3411 timer times out, the terminal device re-initializes the TAU process and starts the T300 timer.

[0042] In combination with the second aspect, in a possible implementation, after the terminal device starts the T300 timer and sends a first message to the first network device, the method also includes: when the T300 timer times out, the terminal device starts the T3411 timer; the terminal device establishes an RRC connection with the second network device, specifically including: when the T3411 timer times out, the terminal device re-initiates the TAU process and establishes an RRC connection with the second network device.

[0043] In combination with the second aspect, in a possible implementation manner, among the neighboring cells of the third cell, the signal strength of the first cell is the largest, and the carrier frequency priority of the first cell is the highest.

[0044] In combination with the second aspect, in a possible implementation manner, the reduced carrier frequency priority corresponding to the first cell is equal to the minimum value of the priorities corresponding to several neighboring cells of the third cell.

[0045] In a third aspect, the present application provides a terminal device, comprising: one or more processors, and one or more memories; the one or more memories are coupled to the one or more processors, the memory is used to store computer program code, the computer program code includes computer instructions, and the one or more processors call the computer instructions to cause the terminal device to perform the method described in the first aspect or any one of the implementations of the first aspect.

[0046] In a fourth aspect, the present application provides a terminal device, comprising: one or more processors, and one or more memories; the one or more memories are coupled to the one or more processors, the memory is used to store computer program code, the computer program code includes computer instructions, and the one or more processors call the computer instructions to enable the terminal device to perform the method described in the second aspect or any one of the implementations of the second aspect.

[0047] In a fifth aspect, the present application provides a computer storage medium comprising computer instructions. When the computer instructions are executed on a terminal device, the terminal device executes the method described in the first aspect or any one of the implementations of the first aspect.

[0048] In a sixth aspect, the present application provides a computer storage medium comprising computer instructions. When the computer instructions are executed on a terminal device, the terminal device executes the method described in the second aspect or any one of the implementations of the second aspect.

[0049] In the seventh aspect, an embodiment of the present application provides a chip system, which is applied to a terminal device, and the chip system includes at least one processor and an interface, and the interface is used to receive instructions and transmit them to the at least one processor; the at least one processor runs the instructions, so that the terminal device executes the method described in the first aspect or any one implementation of the first aspect.

[0050] In the eighth aspect, an embodiment of the present application provides a chip system, which is applied to a terminal device, and the chip system includes at least one processor and an interface, and the interface is used to receive instructions and transmit them to the at least one processor; the at least one processor executes the instructions so that the terminal device executes the method described in the second aspect or any one of the implementation methods of the second aspect.

[0051] In a ninth aspect, an embodiment of the present application provides a computer program product comprising instructions, which, when executed on a terminal device, enables the terminal device to execute the method described in the first aspect or any one of the implementations of the first aspect.

[0052] In a tenth aspect, an embodiment of the present application provides a computer program product comprising instructions, which, when executed on a terminal device, enables the terminal device to execute the method described in the second aspect or any one of the implementations of the second aspect.

[0053] It can be understood that the terminal device provided in the third aspect, the computer storage medium provided in the fifth aspect, the chip system provided in the seventh aspect, and the computer program product provided in the ninth aspect are all used to execute the method described in the first aspect or any one of the implementations of the first aspect. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects of any possible implementation of the first aspect, which will not be repeated here. The terminal device provided in the fourth aspect, the computer storage medium provided in the sixth aspect, the chip system provided in the eighth aspect, and the computer program product provided in the tenth aspect are all used to execute the method described in the second aspect or any one of the implementations of the second aspect. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects of any possible implementation of the second aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of a cell reselection process provided in an embodiment of the present application;

[0055] Figure 2 A schematic diagram of a communication method provided in an embodiment of the present application;

[0056] Figure 3 A schematic diagram of the structure of a modem provided in an embodiment of the present application;

[0057] Figure 4 A schematic diagram of a network architecture provided in an embodiment of the present application;

[0058] Figure 5 A flowchart of another communication method provided in an embodiment of the present application;

[0059] Fig. 6A A flowchart of another communication method provided in an embodiment of the present application;

[0060] Figure 6B A flowchart of another communication method provided in an embodiment of the present application;

[0061] Figure 7 A schematic diagram of the hardware structure of a UE provided in an embodiment of the present application;

[0062] Figure 8 A schematic diagram of the software structure of a UE provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0064] It should be understood that the terms "first", "second", etc. in the specification, claims and drawings of the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0065] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0066] First, some of the terms and related technologies involved in this application are explained to facilitate understanding by those skilled in the art.

[0067] 1. Idle state (i.e. idle state) and connected state (i.e. connected state)

[0068] In some embodiments of the present application, the state of the UE may include a connected state and an idle state. When the UE is powered on but no RRC connection is established with the network side, the UE is in an idle state. When the UE establishes an RRC connection with the network side, the UE is in a connected state.

[0069] In some other embodiments of the present application, the state of the UE may also include a connecting state (ie, a connecting state). In this state, the UE is trying to establish an RRC connection with the network, sending a corresponding request message and waiting for a response from the network.

[0070] In some other embodiments of the present application, the state of the UE may further include a deactivated state (ie, an inactive state). The deactivated state is also referred to as a low power consumption state.

[0071] It can be understood that the processes that the UE in the idle state needs to complete include public land mobile network (PLMN) selection, cell selection / cell reselection, location registration, etc.

[0072] 2. Community selection

[0073] When the UE changes from a connected state to an idle state (for example, a radio link failure, entering an airplane mode, etc.), or when the UE selects a PLMN, the UE needs to perform a cell selection, that is, the UE needs to select a cell to reside in.

[0074] There are two types of cell selection:

[0075] (1) Initial cell selection

[0076] When the UE does not store any Evolved Universal Terrestrial Radio Access (E-UTRA) carrier frequency information (for example, when the UE is powered on for the first time), the UE can scan all E-UTRA bands according to its own capabilities. Once a suitable cell is found, the UE will select the cell to reside in. It should be noted that on each carrier frequency, the UE only needs to search for the cell with the largest signal strength.

[0077] (2) Cell selection based on stored information

[0078] If the UE has stored some previous E-UTRA carrier frequency information and some cell parameter information, the UE can search for these carrier frequencies and cells first. Once a suitable cell is found, the UE will select the cell to reside in. If no suitable cell is found in the stored information, the UE will start the above initial cell selection.

[0079] It should be noted that the above “finding a suitable cell” means that the cell meets the S criterion and the cell allows the UE to reside.

[0080] It is worth noting that, during the cell selection process, regardless of whether the carrier frequency information is stored in the UE, the UE will not select a cell based on the carrier frequency priority, but only based on the cell signal strength and the S criterion.

[0081] S quasi side means: Srxlev>0 and Squal>0. That is, if a cell meets S quasi side, then the cell must meet both Srxlev>0 and Squal>0. The specific meanings of Srxlev and Squal can be referred to in relevant technical documents and will not be elaborated here.

[0082] 3. Cell reselection

[0083] According to the above, after the UE performs cell selection, it can reside in a suitable cell. However, the cell where the UE resides is not necessarily the best cell in the nearby area. Therefore, when the UE successfully resides in a cell, it may immediately reselect the cell. It should be noted that the cell reselection is performed by the UE in the idle state and is controlled by the UE.

[0084] In some embodiments of the present application, the UE can initiate cell reselection only after the UE resides on the cell it selected for a certain period of time (for example, 1 second).

[0085] After the UE successfully resides in a cell, if no RRC connection is initiated (i.e., the RRC connection establishment process or the RRC connection re-establishment process is initiated), the UE will start the measurement in the idle state. If the signal quality of the current cell is poor, such as weak signal strength, and the signal strength of the neighboring cell (i.e., the adjacent cell) is strong, the UE will try to reselect to reside in the neighboring cell with stronger signal strength. In this case, the UE can first try to receive the system message of the neighboring cell with stronger signal strength, and then determine whether the cell is suitable for residence based on the system message of the cell. If the UE determines that the cell is suitable for residence based on the system message of the cell, the UE will reselect to reside in the cell, and restart the measurement to continue monitoring the signal strength of the current cell and the adjacent cell.

[0086] See also Figure 1 , Figure 1 A schematic diagram of a cell reselection process provided in an embodiment of the present application. Figure 1 As shown, the cell reselection process may include four stages: an evaluation stage, a preparation stage, a decision stage, and an execution stage. In the evaluation stage of cell reselection, the UE has been stationed in cell A. At this time, the UE can measure and evaluate the neighboring cells of cell A. Next comes the preparation stage of cell reselection. In this preparation stage, the UE can determine whether there is a target cell in the neighboring cells of cell A according to the cell reselection rule. If the UE determines that there is a target cell in the neighboring cells of cell A according to the cell reselection rule, the UE can receive the system message of the target cell. However, if the UE determines that there is no target cell in the neighboring cells of cell A according to the cell reselection rule, the UE can return to the evaluation stage of cell reselection and continue to measure and evaluate the neighboring cells of cell A. Among them, the target cell refers to a cell that meets the cell reselection rule. That is, the UE can determine whether there is a cell (i.e., a target cell) that meets the cell reselection rule in the neighboring cells of cell A. If so, the UE can receive the system message of the cell that meets the cell reselection rule, otherwise, the UE continues to measure and evaluate the neighboring cells of cell A. In the case where the UE receives the system message of the target cell, the UE may enter the decision phase of cell reselection. In the decision phase, the UE may determine whether the target cell is accessible based on the system message of the target cell it receives. If the target cell allows the UE to access, the UE enters the execution phase of cell reselection. In the execution phase, the UE may reside in the target cell. However, if the target cell does not allow the UE to access, the UE returns to the preparation phase of cell reselection.

[0087] According to the above, if the signal strength of a cell is relatively strong and its priority is relatively high, it is not easy for the UE to reselect other cells.

[0088] It is understandable that the specific meanings of the cell reselection rules, signal strength and priority can be found in the relevant technical documents and will not be elaborated here.

[0089] 4. Cell Handover (HO)

[0090] The UE can receive the measurement indication sent by the current cell, and based on the measurement indication, measure and evaluate the signal strength of the neighboring cell of the current cell, etc., to obtain the measurement result. The UE can generate a corresponding measurement report (Measurement Report, MR) based on the measurement result, and send the measurement report to the current cell. After the cell where the UE currently resides receives the measurement report, it can communicate with the neighboring cell based on the measurement report. If the neighboring cell allows access, the cell where the UE currently resides can instruct the UE to perform cell switching.

[0091] It can be understood that the cell switching is performed when the UE is in a connected state. The cell switching can keep the UE communication uninterrupted.

[0092] In addition, the measurement result obtained by the UE may indicate that the signal strength of cell B is greater and cell B has a higher priority. When cell A learns that cell B allows UE access, cell A may instruct the UE to switch the resident cell from cell A to cell B.

[0093] If cell B is a problem cell, the UE may experience RLF when camping on cell B due to reasons such as failure to read system information. In this way, the UE will perform cell selection. Since the UE previously camped on cell B and the signal strength of cell B is relatively strong, the UE still chooses cell B to camp. In this case, the UE will initiate the RRC connection reestablishment process and prepare to send an RRC connection reestablishment request (RRCConnectionReestablishment Request). Once the RRC connection fails, the UE enters the idle state and the UE performs cell reselection. Since the signal strength and priority of cell B are better than other neighboring cells of cell B (for example, the signal strength of cell B is relatively strong and the priority of cell B is relatively high), the UE will still choose cell B to camp, initiate the RRC connection establishment process, and prepare to send an RRC connection request (RRCConnection Request). Once the RRC connection fails, the UE enters the idle state again and performs cell reselection again. Since the signal strength of cell B is relatively strong and the priority of cell B is relatively high, the UE will still choose cell B to camp and initiate the RRC connection establishment process again. This means that if the UE cannot successfully establish an RRC connection with the network device corresponding to cell B, the UE will always select cell B to reside and initiate the RRC connection establishment process. That is, the UE will cyclically perform the following steps: the UE selects cell B to reside and initiates the RRC connection establishment process, and the RRC connection establishment fails.

[0094] It is understandable that if the UE executes the above steps for a large number of cycles, it may cause the UE call to end (i.e., call drop) and long-term call silence. For example, once the time for the UE to select cell B and finally successfully establish an RRC connection exceeds a certain threshold (e.g., 20 seconds), after the UE successfully establishes an RRC connection with cell B, the UE will actively send a BYE message to cell B, causing the UE call to end. In addition, since the UE is in a call state, as long as the UE has not successfully established an RRC connection with cell B, the call on the UE cannot continue, that is, the call on the UE will be silent.

[0095] The following is based on Figure 2 The above-mentioned problem is explained by way of example.

[0096] like Figure 2 As shown, Figure 2 A communication method is provided in an embodiment of the present application. The method may include but is not limited to the following steps:

[0097] S1: The UE stays in cell A and makes a call.

[0098] It is understandable that the UE can camp on cell A and make a call while camping on cell A.

[0099] S2: The UE sends an A3 MR to the network device corresponding to cell A.

[0100] After measuring and evaluating the neighboring cells of cell A, the UE may send the A3 MR to the network device corresponding to cell A.

[0101] Correspondingly, the network device corresponding to cell A can receive the A3 MR sent by the UE.

[0102] S3: The UE sends an RRC connection reconfiguration message to the network device corresponding to cell A. The RRC connection reconfiguration message is used to instruct the UE to switch the cell it resides in from cell A to cell B.

[0103] After receiving the A3 MR sent by the UE, the network device corresponding to the cell A may send an RRC connection reconfiguration message (RRCConnectionReconfiguration) to the UE. The RRC connection reconfiguration message may be used to instruct the UE to switch from the cell A to the cell B.

[0104] S4: The UE sends an RRC connection reconfiguration completion message to the network device corresponding to cell B.

[0105] After receiving the RRC connection reconfiguration message, the UE may switch to cell B to reside, and send an RRC connection reconfiguration complete message (RRCConnectionReconfigurationComplete) to the network device corresponding to cell B.

[0106] Correspondingly, the network device corresponding to cell B can receive the RRC connection reconfiguration completion message.

[0107] S5: The UE sends a TAU request to the network device corresponding to cell B.

[0108] After the UE switches from cell A to cell B, a TAU process can be initiated. In some embodiments of the present application, after the UE switches from cell A to cell B, once a change in TA is detected, a TAU process can be initiated. Specifically, the UE can send a TAU request to the network device corresponding to cell B to initiate the TAU process.

[0109] S6: RLF is caused by a SIB (System Information Block) read failure corresponding to cell B, and the UE performs cell selection and chooses to stay in cell B.

[0110] After the UE switches from cell A to cell B for residence, it can read the system message corresponding to cell B. Since the RLF is caused by the failure to read the system information (SIB read failure) corresponding to cell B, the UE needs to select a cell. In some embodiments of the present application, since the signal strength of the current cell B is the largest, the UE will still choose cell B to reside. In some embodiments of the present application, the UE can perform cell selection based on the previously stored carrier frequency information and cell parameters. Since cell B is the cell with the largest signal strength among the several cells corresponding to the carrier frequency information and cell parameters, the UE selects cell B to reside.

[0111] It can be understood that the failure to read the system message corresponding to cell B may be that the UE does not receive the system message of cell B (such as SIB message), or that the UE receives the system message of cell B but fails to parse it successfully.

[0112] In some embodiments of the present application, the UE may generate a TAU request, but before sending the TAU request, RLF occurs due to failure to read the system message corresponding to cell B. In this case, the UE needs to establish an RRC connection before sending the TAU request.

[0113] S7: The UE generates an RRC connection re-establishment request and starts the T301 timer. Before the UE sends the RRC connection re-establishment request, it first needs to perform random access.

[0114] After the UE chooses to camp on cell B, it can generate an RRC connection reestablishment request and start the T301 timer. It can be understood that if the UE needs to send an RRC connection reestablishment request, the UE first needs to perform random access. The first step of random access is that the UE sends MSG1.

[0115] It is understandable that the present application does not limit the specific sequence of the UE generating the RRC connection re-establishment request and starting the T301 timer. The interval between the UE generating the RRC connection re-establishment request and starting the T301 timer can be shorter.

[0116] S8: UE sends MSG1 to the network device corresponding to cell B.

[0117] The UE may send MSG1 to the network device corresponding to cell B.

[0118] It should be noted that if Figure 2As shown, when there is no response to MSG1 sent by UE to the network device corresponding to cell B, UE can retransmit MSG1 to the network device corresponding to cell B. In some embodiments of the present application, if there is no response to MSG1 sent by UE, UE can retransmit MSG1 multiple times.

[0119] It is understandable that the lack of response to MSG1 sent by the UE is only an example of random access failure and should not be regarded as a limitation to the present application. There may be other random access failures. For example, there is no response to MSG3 sent by the UE.

[0120] S9: The T301 timer times out, the UE enters the idle state, and the RRC layer in the UE notifies the NAS layer that a lower layer failure has occurred. The UE determines that the TAU has failed based on the notification and starts the T3411 timer.

[0121] If the UE does not receive an RRC connection re-establishment message or an RRC connection re-establishment rejection message within the period defined by the T301 timer, the T301 timer times out. When the T301 timer times out, the UE enters the idle state, and the RRC layer in the UE can notify the NAS layer that a lower layer failure has occurred (because the UE has not received an RRC connection re-establishment message or an RRC connection re-establishment rejection message within the period defined by the T301 timer, it can be considered that a lower layer failure has occurred, and the lower layer failure can refer to the description in the relevant standard protocol 3GPP TS 24008). The UE can start the T3411 timer based on the notification. It can be understood that the UE can determine the TAU failure based on the notification before starting the T3411 timer.

[0122] It can be understood that the RRC layer in the UE notifies the NAS layer of a lower layer failure, which can indicate that the RRC connection re-establishment has failed, that is, the RRC connection has not been successfully established. In this case, the UE cannot send a TAU request, nor can it receive a response message sent by the corresponding network device, and the UE can determine that the TAU has failed.

[0123] Understandable, such as Figure 3 As shown, the RRC layer and the NAS layer may be two modules in the modem of the UE. Among them, the RRC layer is a lower module of the NAS layer. The modem may include four layers, namely, the ML1 layer, the ML2 layer, the ML3 layer and the ML4 layer. Among them, the ML1 layer refers to the PHY layer. The ML2 layer refers to the MAC layer, the RLC layer and the PDCP layer. The ML3 layer refers to the RRC layer. The ML4 layer refers to the NAS layer. The specific meanings of the PHY layer, the MAC layer, the RLC layer, the PDCP layer, the RRC layer and the NAS layer can be referred to the relevant technical documents, which will not be described in detail here.

[0124] S10: The UE performs cell reselection and chooses to continue to stay in cell B.

[0125] It is understandable that after the UE enters the idle state, it can reselect a cell. The UE chooses to continue to reside in cell B according to the cell reselection rule and the signal strength and priority of the current cell (cell B) and its neighboring cells (cell B's neighboring cells). This means that the cell selected by the UE to reside does not change.

[0126] In some embodiments of the present application, since the signal strength of cell B is greater and the priority of cell B is higher, the UE will still choose cell B to camp on.

[0127] In some embodiments of the present application, since the signal strength of the current cell B is the largest and its priority is the highest, the UE may choose to continue to stay in cell B.

[0128] S11: The T3411 timer times out, and the UE re-initiates the TAU process. When the UE initiates the TAU process, it needs to initiate the RRC connection establishment process and start the T300 timer. When the UE initiates the RRC connection establishment process, it first needs to perform random access.

[0129] After the T3411 timer times out, the UE can re-initiate the TAU process. To initiate the TAU process, the UE needs to initiate the RRC connection establishment process and start the T300 timer. To initiate the RRC connection establishment process, random access is required first. The first step of random access is for the UE to send MSG1.

[0130] S12: UE sends MSG1 to the network device corresponding to cell B.

[0131] Since the UE continues to reside in cell B, it can send MSG1 to the network device corresponding to cell B when performing random access.

[0132] It should be noted that if Figure 2 As shown, when there is no response to MSG1 sent by UE to the network device corresponding to cell B, UE can retransmit MSG1 to the network device corresponding to cell B. In some embodiments of the present application, if there is no response to MSG1 sent by UE, UE can retransmit MSG1 multiple times.

[0133] It is understandable that the specific implementation of step S12 can refer to the relevant description of step S8, which will not be repeated here.

[0134] S13: The T300 timer times out and the UE enters the idle state. The RRC layer in the UE notifies the NAS layer that a lower layer failure has occurred. The UE determines that the TAU has failed based on the notification and starts the T3411 timer.

[0135] If there is no response to the MSG1 sent by the UE, the UE enters the idle state after the T300 timer expires. At this time, the UE can determine that the TAU has failed and start the T3411 timer again.

[0136] S14: The UE performs cell reselection and chooses to continue to stay in cell B.

[0137] It is understandable that after the UE enters the idle state, it can reselect a cell. Similar to the above, the UE still selects cell B to reside.

[0138] S15: The T3411 timer times out, and the UE re-initiates the TAU process. When the UE initiates the TAU process, it needs to initiate the RRC connection establishment process and start the T300 timer. When the UE initiates the RRC connection establishment process, it first needs to perform random access.

[0139] S16: UE sends MSG1 to the network device corresponding to cell B.

[0140] S17: The T300 timer times out and the UE enters the idle state. The RRC layer in the UE notifies the NAS layer that a lower layer failure has occurred. The UE determines that the TAU has failed based on the notification and starts the T3411 timer.

[0141] It can be understood that the specific implementation of steps S14 to S17 can refer to the relevant description of steps S10 to S13, which will not be repeated here.

[0142] S18: The UE performs cell reselection and chooses to continue to stay in cell B.

[0143] It is understandable that after the UE enters the idle state, it can reselect a cell. Similar to the above, the UE still selects cell B to reside.

[0144] S19: T3411 timer times out, and UE re-initiates TAU procedure. When UE initiates TAU procedure, it needs to initiate RRC connection establishment procedure and start T300 timer. When UE initiates RRC connection establishment procedure, it needs to perform random access first.

[0145] S20: UE sends MSG1 to the network device corresponding to cell B.

[0146] It can be understood that the specific implementation of steps S18 to S20 can refer to the relevant description of steps S10 to S12, which will not be repeated here.

[0147] S21: After the UE sends MSG1 more than 30 times, it successfully establishes an RRC connection with the network device corresponding to cell B.

[0148] It can be understood that after the above steps S10 to S13 are repeated multiple times, the UE can successfully establish an RRC connection with the network device corresponding to cell B. In some embodiments of the present application, such as Figure 2 As shown, the UE successfully establishes an RRC connection with cell B only after sending MSG1 to cell B for more than 30 times. The UE and cell B can establish an RRC connection through a random access process, such as carrying an RRC connection request (RRC Connection Request) through MSG3 in the random access process, carrying an RRC connection establishment message (RRC Connection Setup) through MSG4 in the random access process, and carrying an RRC connection establishment completion message (RRC Connection Complete) through MSG5 in the random access process.

[0149] S22: The UE sends a BYE message to the network device corresponding to cell B.

[0150] It is understandable that if there is a long period of silence during the UE call, the call is likely to be dropped, that is, the call is ended. In some embodiments of the present application, the time for the UE to successfully establish an RRC connection with the network device corresponding to the cell B is relatively long, and voice data cannot be sent during this period, so silence will occur.

[0151] In some embodiments of the present application, Figure 2 As shown, the UE successfully establishes an RRC connection with the network device corresponding to cell B only after sending MSG1 to the network device corresponding to cell B for more than 30 times. In this case, since the time from the occurrence of RLF to the UE establishing the RRC connection exceeds 20 seconds, the UE determines that the Realtime Transport Protocol (RTP) / Realtime Transport Control Protocol (RTCP) has timed out, and after the UE establishes the RRC connection with the network device corresponding to cell B, it sends a BYE message to the network device corresponding to cell B, so that the call ends.

[0152] S23: The UE interface displays that the call is hung up.

[0153] It is understood that after the UE sends a BYE message to the network device corresponding to cell B, the call hang-up can be displayed on the interface. In this process, the UE automatically hangs up the call by sending a BYE message to the network device corresponding to cell B. It is understood that the BYE message is used to terminate a specified session or an attempted session, that is, to announce that a device or service has left the network. For example, during a call, the UE can send a BYE message to the current resident cell to end the call.

[0154] It should be noted that the T301 timer is a timer for RRC reconstruction. The T301 timer is turned on when the UE transmits an RRC connection reconstruction request. It is understandable that the UE needs to perform random access first when transmitting an RRC connection reconstruction request. Specifically, the UE upper module transmits the need for the UE to transmit an RRC connection reconstruction request to the lower module, and the lower module will first perform random access after receiving it. The first step of random access is for the UE to send MSG1. Therefore, it can be understood that the T301 timer starts timing from the time the UE sends MSG1. When the UE receives RRCConnectionReestablishment (RRC connection reconstruction message) or RRCConnectionReestablishmentReject (RRC connection reconstruction rejection message), the T301 timer stops timing. If the UE does not receive the above message within the period defined by the T301 timer, it is recorded as the T301 timer timeout. The T300 timer is a timer for RRC connection establishment. The T300 timer is turned on when the UE transmits an RRC connection request. It is understandable that the UE needs to perform random access first when transmitting an RRC connection request. Specifically, the UE upper module transmits the UE's need to transmit the RRC connection request to the lower module, and the lower module will first perform random access after receiving it. The first step of random access is for the UE to send MSG1. Therefore, it can be understood that the T300 timer starts timing from the time the UE sends MSG1. When the UE receives RRCConnectionSetup (RRC connection establishment message) or RRCConnectionReject (RRC connection rejection message), the T300 timer stops timing. If the UE does not receive the above message within the period defined by the T300 timer, it is recorded as a T300 timeout. The T3411 timer is a timer that is started after a TAU failure. After T3411 times out, the UE initiates the TAU process again. In other words, the period defined by the T3411 timer is equal to the interval duration for the UE to initiate the TAU process.

[0155] In some embodiments of the present application, when the UE executes step S5, the UE is in a connected state. When the UE executes steps S6, S10, S14, and S18, the UE is in an idle state. When the UE executes steps S7-S8, S12, S16, and S20, the UE is in a connecting state.

[0156] The embodiment of the present application provides a communication method and related equipment. According to the method, once the UE continues to reside in a problem cell during a call, the UE can reduce the priority of the problem cell, so that the UE can subsequently select other cells to reside in through cell reselection, thereby avoiding dropped calls and silent problems caused by long-term residence in the problem cell.

[0157] In order to better understand a communication method and related equipment provided in an embodiment of the present application, the network architecture used in an embodiment of the present application is described below.

[0158] See also Figure 4 , Figure 4 A schematic diagram of a network architecture provided in an embodiment of the present application. Figure 4 As shown, the network architecture may include at least two cells (e.g., cell A belonging to network device 1 and cell B belonging to network device 2) and at least one UE. Cell A may be a cell where the UE resides. Cell B may be a neighboring cell (i.e., an adjacent cell) of cell A. That is, cell B is a cell in at least one neighboring cell of cell A.

[0159] In some embodiments of the present application, a network device may correspond to one or more cells. Cell A and cell B may belong to the same network device. That is, network device_1 and network device_2 may be the same network device. In this case, the UE performs a handover within the network device. Optionally, cell A and cell B may belong to different network devices. That is, network device_1 and network device_2 may be different network devices. In this case, the UE performs a handover between network devices.

[0160] The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: Global System for Mobile Communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), LTE system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, Universal Mobile Telecommunications System (UMTS) system, Enhanced Data Rate for GSM Evolution (EDGE) system, Worldwide Interoperability for Microwave Access (WiMAX) system. The technical solution of the embodiment of the present application can also be applied to other communication systems, such as a public land mobile network (PLMN) system, a fifth generation (5G) system or a communication system after 5G or a new wireless (NR), etc., and the embodiment of the present application is not limited to this.

[0161] The UE in the embodiment of the present application may also be referred to as a terminal device, a user terminal, a mobile station (MS), a mobile terminal (MT), etc. The terminal device may be a device that includes a wireless transceiver function and can cooperate with a network device to provide communication services for users. The terminal device may be a handheld terminal, a laptop computer, a subscriber unit, a cellular phone, a smart phone, a wireless data card, a personal digital assistant (PDA) computer, a tablet computer, a wireless modem, a handheld device (handheld), a laptop computer (Laptop Computer), a cordless phone (Cordless Phone) or a wireless local loop (Wireless Local Loop, WLL) station, a machine type communication (Machine Type Communication, MTC) terminal, a wearable device (such as a smart watch, a smart bracelet, a pedometer, etc.), an in-vehicle device (such as a car, a bicycle, an electric car, an airplane, a ship, a train, a high-speed rail, etc.), a virtual reality (Virtual Reality, VR) device, an augmented reality (Augmented Reality, AR) device, a wireless terminal in industrial control (Industrial Control), a smart home device (such as a refrigerator, a television, an air conditioner, an electric meter, etc.), an intelligent robot, a workshop device, a wireless terminal in self-driving, a remote medical operation (Remote Medical Surgery), wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, flying equipment (for example, smart robots, drones) or wireless terminals in 5G networks or future communication networks, etc., which are not specifically limited in the embodiments of the present application.

[0162] The network device in the embodiment of the present application may be a device for communicating with the UE. For example, the network device may be a base station (Base Transceiver Station, BTS) in a Global System for Mobile Communications (GSM) system or a Code Division Multiple Access (CDMA), or a base station (NodeB, NB) in a Wideband Code Division Multiple Access (WCDMA) system, or an evolutionary base station (eNB or eNodeB) in an LTE system, or a wireless controller in a Cloud Radio Access Network (CRAN) scenario, or the network device may be a relay station, an access point, a vehicle-mounted device, a wearable device, and a network device in a future 5G network or a network after 5G, or a network device in a future evolved PLMN network, etc., for example, a transmission point (TRP or TP) in an NR system, a base station (gNB) in an NR system, one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, etc., and the embodiments of the present application are not limited to this.

[0163] Optionally, the base station in the embodiment of the present application may include various forms of base stations, such as: macro base stations, micro base stations (also called small stations), relay stations, access points, next-generation base stations (gNodeB, gNB), transmission points (Transmitting and Receiving Point, TRP), transmission points (Transmitting Point, TP), mobile switching centers, and devices that perform base station functions in device-to-device (Device-to-Device, D2D), vehicle-to-everything (V2X), and machine-to-machine (Machine-to-Machine, M2M) communications, etc. The embodiments of the present application do not specifically limit this.

[0164] The embodiments of the present application do not specifically limit the specific structure of the execution subject of the method provided in the embodiments of the present application, as long as it is possible to communicate according to the method provided in the embodiments of the present application by running a program that records the code of the method provided in the embodiments of the present application. For example, the execution subject of the method provided in the embodiments of the present application may be a UE or a network device, or a functional module in the UE or the network device that can call and execute a program.

[0165] Based on the above network architecture, a communication method provided by an embodiment of the present application is introduced below.

[0166] See also Figure 5 , Figure 5 A flowchart of another communication method provided in an embodiment of the present application. The communication method may include but is not limited to the following steps:

[0167] S101: A network abnormality occurs during a call between UE and the network.

[0168] Specifically, the UE may experience a network anomaly while making a call in the cell where it originally resides (for example, cell A), or may experience a network anomaly while making a call in another cell (for example, cell B), and this application does not limit this. Exemplarily, the network anomaly may include but is not limited to the following three situations:

[0169] In some embodiments of the present application, a network abnormality occurs when the UE is camped on cell A and is making a call.

[0170] In some embodiments of the present application, the UE originally resides in cell A for a call. After the UE sends a corresponding measurement report (MR) to network device 1, network device 1 can instruct the UE to switch (HO) from cell A to cell B for a call based on the measurement report. A network abnormality occurs during the UE's call in cell B.

[0171] Specifically, network device_1 may send an RRC connection reconfiguration message (RRCConnectionReconfiguration) to the UE. The RRC connection reconfiguration message may be used to instruct the UE to switch from cell A to cell B for residence. After receiving the RRC connection reconfiguration message, the UE may switch to cell B for residence and send an RRC connection reconfiguration complete message (RRCConnectionReconfigurationComplete) to network device_2. Accordingly, network device_2 may receive the RRC connection reconfiguration complete message. After network device_2 receives the RRC connection reconfiguration complete message, the UE completes the switch from cell A to cell B.

[0172] It is understandable that the measurement report sent by the UE to the network device_1 can be an A3 MR (also known as an A3 event), or other types of measurement reports such as an A5 MR (also known as an A5 event), and the present application does not limit this. It is understandable that A3MR indicates that the quality of the neighboring cell is higher than an absolute threshold than that of the serving cell. A5 MR can indicate that the quality of the serving cell is lower than an absolute threshold, and the quality of the neighboring cell is higher than an absolute threshold. It is understandable that the serving cell refers to the cell currently providing service to the UE. In some embodiments of the present application, the serving cell of the UE can be understood as the cell where the UE is currently residing. It is understandable that the specific meanings of the measurement report, A3 MR and A5 MR can refer to the relevant technical documents and will not be elaborated here.

[0173] In some embodiments of the present application, the UE originally resides in cell A for a call. The UE may also reside in cell B through cell reselection or the like. During the process of the UE residing in cell B for a call, a network abnormality occurs.

[0174] In some embodiments of the present application, the network anomaly may be a radio link failure. In one possible implementation, after the UE receives a system information read failure (SIB read failure) message, it may determine that the radio link has failed. In another possible implementation, the cause of the radio link failure may include any one or more of the following: uplink radio link control (RLC) reaching the maximum number of retransmissions, preamble message reaching the maximum number of transmissions, and downlink out-of-sync.

[0175] In some embodiments of the present application, the network abnormality may be an RRC connection release (RRCConnectionRelease).

[0176] In some embodiments of the present application, the network anomaly may be a periodic TAU failure of the UE. The full name of TAU in English is Tracking Area Update. TAU can be divided into periodic TAU and aperiodic TAU. Periodic TAU refers to the UE periodically sending a TAU request (TAU Request) to the Mobility Management Entity (MME) to ensure that the UE can respond to the network's paging for data transmission. Aperiodic TAU refers to a TAU triggered by other reasons (for example, HO).

[0177] In some embodiments of the present application, the network abnormality may be a handover (HO) failure.

[0178] It is understandable that the network anomaly occurring during a UE call may also include other contents, which are not limited in this application.

[0179] S102: The UE performs cell selection or cell reselection and chooses to reside in cell B.

[0180] After a network abnormality occurs during a UE call, the UE may perform cell selection or cell reselection and select cell B to reside.

[0181] It is understandable that the UE can determine whether to perform cell selection or cell reselection based on the specific network anomaly that occurs during a call. For example, when the network anomaly that occurs during a UE call is RLF, the UE performs cell selection. For example, when the network anomaly that occurs during a UE call is RRC connection release, the UE performs cell reselection. For example, when the network anomaly that occurs during a UE call is UE periodic TAU failure, the UE performs cell reselection. For example, when the network anomaly that occurs during a UE call is a handover failure, the UE performs cell selection.

[0182] It can be understood that among several neighboring cells of the cell where the UE is currently staying, the signal strength of cell B is greater and the priority is higher. This means that the signal strength and priority of cell B are better than other neighboring cells of the cell where the UE is currently staying. In some embodiments of the present application, among several neighboring cells of the cell where the UE is currently staying, the signal strength of cell B is the greatest and the priority of cell B is the highest.

[0183] In some embodiments of the present application, the cell where the UE currently resides is cell A. Cell B is a neighboring cell of cell A. That is, cell B is a neighboring cell of the cell where the UE currently resides. In this case, since the signal strength of cell B is greater and the priority is higher, the UE can choose cell B to reside in when performing cell reselection.

[0184] In some embodiments of the present application, the cell in which the UE currently resides is cell B. In this case, since the UE originally resides in cell B, the UE stores the carrier frequency information and cell parameter information of cell B. When the UE performs cell selection, it can preferentially select a cell based on the stored carrier frequency information and cell parameter information, and the UE can give priority to cell B. Since the signal strength of cell B is the largest, the UE can select cell B to reside.

[0185] S103: The UE triggers to establish an RRC connection with network device_2, and starts a first timer. Network device_2 is the network device corresponding to cell B.

[0186] After the UE performs cell selection or cell reselection and chooses to reside in cell B, the UE may trigger the establishment of an RRC connection with network device_2 and start a first timer. It can be understood that network device_2 is the network device corresponding to cell B.

[0187] In some embodiments of the present application, the UE can establish an RRC connection with the network device 2 by initiating an RRC connection reestablishment process. In this case, the first timer is a T301 timer. The relevant description of the T301 timer can refer to the above and related technical documents, and will not be repeated here.

[0188] In some embodiments of the present application, the UE may establish an RRC connection with the cell B by triggering an RRC connection establishment procedure. In this case, the first timer is a T300 timer. The relevant description of the T300 timer can be referred to above and related technical documents, and will not be repeated here.

[0189] It should be noted that when the UE initiates the RRC connection reestablishment procedure, what it is going to send is the RRC connection reestablishment request, and when the UE initiates the RRC connection establishment procedure, what it is going to send is the RRC connection establishment procedure.

[0190] It is understandable that the UE can determine whether the UE establishes an RRC connection with network device _2 by initiating an RRC connection reestablishment process or by initiating an RRC connection establishment process based on the network anomaly that occurs during the call.

[0191] For example, if the network abnormality that occurs during the UE's call is RLF, the UE performs cell selection and selects cell B to reside in. After the UE resides in cell B, it initiates an RRC connection reestablishment process.

[0192] For example, if the network abnormality that occurs during the UE's call is RRC connection release, the UE performs cell reselection and selects cell B to reside in. After the UE resides in cell B, it initiates an RRC connection establishment process.

[0193] For example, if the network abnormality that occurs during the UE's call is a periodic TAU failure, the UE performs cell reselection and selects cell B to reside in. After the UE resides in cell B, it initiates an RRC connection establishment process.

[0194] For example, if the network anomaly that occurs during a call of the UE is a handover failure, the UE performs cell selection and selects cell B to reside in. After the UE resides in cell B, an RRC connection reestablishment process is initiated.

[0195] It is understandable that when the UE triggers the establishment of an RRC connection with the network device _2, it first needs to perform random access. Specifically, the UE can send MSG1 to the network device _2. MSG1 is a Random Access Preamble. After the network device _2 receives the MSG1, it sends MSG2 to the UE, and then the random access is completed. MSG2 is a Random Access Response. It is understandable that if the MSG1 sent by the UE to the network device _2 has no response, the UE can retransmit MSG1 to the network device _2. In some embodiments of the present application, if the MSG1 sent by the UE to the network device _2 has no response, the UE can retransmit MSG1 to the network device _2 multiple times.

[0196] It should be noted that, whether the UE establishes an RRC connection with the network device 2 by initiating an RRC connection reestablishment process or by initiating an RRC connection establishment process, the UE first needs to perform random access. For the description of random access, please refer to the above and related technical documents.

[0197] In some embodiments of the present application, the UE is triggered to establish an RRC connection with the network device _2 due to business types such as MO Signalling (i.e., signaling sent by the MO, for example, a TAU request) and MO data (which can be understood as the need for MO to transmit data). The present application does not limit the reason why the UE triggers the establishment of an RRC connection with the network device _2. In a call scenario, MO (Mobile Original) can be understood as the calling device that initiates the call. The relevant meanings of MO Signalling and MO data can be referred to the relevant technical documents and will not be elaborated here.

[0198] S104: The first timer times out, and the UE determines that the RRC connection establishment with the network device_2 fails.

[0199] When the first timer times out, the UE can determine that the RRC connection establishment between it and the network device_2 fails, and the UE enters the idle state. At this time, the UE still resides in the cell B. It can be understood that the timeout of the first timer means that the UE has not successfully established an RRC connection with the network device_2 within the period defined by the first timer.

[0200] In some embodiments of the present application, the first timer is a T301 timer. The T301 timer may start timing when the UE sends MSG1. If the UE does not receive RRCConnectionReestablishment or RRCConnectionReestablishmentReject within the period defined by the T301 timer, the T301 timer times out, and the UE may determine that the RRC connection establishment between it and the network device_2 has failed.

[0201] In some embodiments of the present application, the first timer is a T300 timer. The T300 timer may start timing when the UE sends MSG1. If the UE does not receive an RRCConnectionSetup message or an RRCConnectionReject message within a period defined by the T300 timer, the T300 timer times out, and the UE may determine that the RRC connection establishment between it and the network device_2 has failed.

[0202] In some embodiments of the present application, the reason for the timeout of the first timer may be: there is no response to the MSG1 sent by the UE to the network device 2 (that is, the UE does not receive the response message corresponding to the MSG1 sent by the network device 2). It is understandable that because there is no response to the MSG1 sent by the UE to the network device 2, the UE will retransmit the MSG1 to the network device 2 multiple times, and the multiple retransmissions of the MSG1 by the UE will take a period of time, until the time corresponding to the first timer T300 timer arrives, the UE still does not receive the response message corresponding to the MSG1 sent by the network device 2, and thus fails to receive the RRC Connection Setup message or the RRCConnection Reject message, which causes the T300 timer to time out.

[0203] In some embodiments of the present application, the reason for the first timer timing out may be: there is no response to MSG3 sent by the UE to the network device _2 (that is, the UE has not received the response message corresponding to MSG3 sent by the network device _2). It can be understood that if the UE establishes an RRC connection with the network device _2 by initiating an RRC connection establishment process, then there is no response to MSG3 sent by the UE to the network device _2, which may specifically include: there is no response to the RRC connection request (RRCConnectionRequest) sent by the UE to the network device _2 (the RRC connection request may be carried by MSG3). Similarly, if the UE establishes an RRC connection with the network device _2 by initiating an RRC connection reestablishment process, then there is no response to MSG3 sent by the UE to the network device _2, which may specifically include: there is no response to the RRC connection reestablishment request (RRCConnectionReestablishmentRequest) sent by the UE to the network device _2. It is understandable that because there is no response to the MSG3 sent by the UE to the network device _2, the UE will retransmit MSG3 to the network device _2 multiple times, and it will take some time for the UE to retransmit MSG3 multiple times. Until the duration corresponding to the first timer T300 timer arrives, the UE still has not received the response message corresponding to MSG3 sent by the network device _2, and thus has not received the RRCConnection Setup message or the RRCConnection Reject message, which causes the T300 timer to timeout.

[0204] It is understandable that the first timer may also have other reasons for timing out, and the present application does not impose any specific restrictions on the reasons for timing out of the first timer.

[0205] S105: The UE lowers the priority of cell B, performs cell reselection, and selects another cell to reside in.

[0206] After the RRC connection establishment between the UE and the network device 2 fails and the UE enters the idle state, the UE can lower the priority of cell B. When the priority of cell B is lowered, the UE can reselect the cell. In this case, since the priority of cell B is lowered, the UE can no longer select cell B, but select other cells (for example, cell A) to reside.

[0207] It is understandable that there are many ways for the UE to reduce the priority of cell B, which is not limited in this application. Some ways for the UE to reduce the priority of cell B are listed below.

[0208] In some embodiments of the present application, the UE may put cell B in a low priority queue.

[0209] Exemplarily, when the UE performs cell reselection, it can search for cell A, cell B, cell C, cell D, and cell E. Before the UE lowers the priority of cell B, the low priority queue includes cell A and cell D, the medium priority queue includes cell C, and the high priority queue includes cell B and cell E. The UE can put cell B in the low priority queue. In this way, when the UE performs cell reselection, it will not reselect the problem cell B.

[0210] It is understandable that the low priority queue, medium priority queue and high priority queue can be set according to actual needs. For example, the priority of the cells in the low priority queue is lower than 5, the priority of the cells in the medium priority queue is 5, and the priority of the cells in the high priority queue is not lower than 6.

[0211] In some embodiments of the present application, the UE may reduce the priority of cell B based on the lowest cell priority among the neighboring cells of cell B. Specifically, the UE may reduce the priority of cell B, and the reduced priority of cell B is the same as the lowest cell priority among the neighboring cells of cell B.

[0212] Exemplarily, when the UE performs cell reselection, it can search for cell A, cell B, cell C, cell D, and cell E. Before the UE lowers the priority of cell B, the priority of cell A is 4, the priority of cell B is 6, the priority of cell C is 5, the priority of cell D is 4, and the priority of cell E is 6. The signal strength of cell E is worse than the signal strength of cell B. It can be seen that the lowest cell priority among the neighboring cells of cell B is 4. The UE can lower the priority of cell B to 4. In this way, when the UE performs cell reselection, it will no longer reselect the problem cell B.

[0213] In some embodiments of the present application, the UE may reduce the priority of cell B so that the reduced priority of cell B does not exceed the priorities of f% of neighboring cells of cell B. It is understandable that f may be set according to actual needs, and the present application does not limit this. For example, f may be 80.

[0214] In some embodiments of the present application, the priority of a cell may be understood as the carrier frequency priority corresponding to the cell, or referred to as frequency point priority.

[0215] It can be understood that the triggering of cell reselection and the execution of cell reselection require the UE to meet several conditions. For example, the length of time that the UE resides on the current cell needs to reach a specified length of time (for example, 1 second) before cell reselection can be performed. For another example, during the cell reselection process, the UE's evaluation time for the target cell needs to reach a certain length of time (for example, 3 seconds) before cell reselection can be performed. This means that after the UE lowers the priority of cell B, the cell reselection will not be performed immediately, and the cell reselection process will take a certain amount of time (for example, the UE's evaluation time for the target cell). That is, after the UE lowers the priority of cell B, the UE needs to wait for cell reselection and wait to execute cell reselection.

[0216] In some embodiments of the present application, after the UE lowers the priority of cell B, the cell reselection can be accelerated, thereby reducing the time spent on the problem cell and reducing the silent time during the call to a certain extent. The specific method of accelerating the cell reselection can refer to the relevant description of step S211, which will not be described in detail here.

[0217] In some embodiments of the present application, after the UE executes step S104 and before executing step S105, the UE may perform cell reselection. After the UE executes step S104 and before executing step S105, since the signal strength and priority of cell B are better than other cells, and the UE has been resident on cell B, the UE selects cell B for M cell reselections, and after selecting cell B for M times, no RRC connection is successfully established with network device_2. In this case, the UE can lower the priority of cell B (i.e., execute step S105). It can be understood that the way in which the UE lowers the priority of cell B can be referred to above, and will not be described in detail here.

[0218] It is understandable that M can be a non-negative integer. The specific value of M can be set according to actual needs, and this application does not impose any restrictions on this. For example, M can be 1. Specifically, after the UE executes step S104, it can reselect the cell. Since the signal strength and priority of cell B are better than other cells (for example, the signal strength of cell B is greater and the priority of cell B is higher), the UE still selects cell B. If the UE still cannot successfully establish an RRC connection, the UE lowers the priority of cell B. That is, after the UE executes step S104, after one cell reselection, it still chooses cell B to reside, but still fails to successfully establish an RRC connection, then the UE can execute step S105, that is, lower the priority of cell B.

[0219] S106: The UE triggers the establishment of an RRC connection with the network device corresponding to the cell where it resides, and starts a second timer.

[0220] After the UE selects other cells (cells other than cell B) to reside in through cell reselection, it can trigger the UE to establish an RRC connection with the network device corresponding to the cell where the UE resides, and start the second timer.

[0221] In some embodiments of the present application, the UE establishes an RRC connection with a network device corresponding to the cell where the UE resides by initiating an RRC connection establishment process. In this case, the second timer may be a T300 timer.

[0222] It is understandable that the reason why the UE triggers the establishment of an RRC connection with the network device corresponding to the cell where it resides may be MoSignalling, MO data, etc. For example, since the UE is in a call and the UE needs to transmit voice packets, the UE can trigger the establishment of an RRC connection with the network device corresponding to the cell where it resides. For another example, if the UE initiates a periodic TAU, it needs to establish an RRC connection with the network device corresponding to the cell where it resides.

[0223] S107: The UE successfully establishes an RRC connection with the network device corresponding to the cell where it resides, and the second timer stops timing.

[0224] After the UE successfully establishes an RRC connection with the network equipment corresponding to the other cells that it reselects after lowering the priority of cell B, the second timer stops timing.

[0225] In some embodiments of the present application, the second timer is a T300 timer. In this case, after the UE receives the RRCConnectionSetup, the second timer stops timing. At this time, the UE successfully establishes an RRC connection with the network device corresponding to the cell where it resides.

[0226] S108: The UE camps on another cell to make a call.

[0227] After the UE successfully establishes an RRC connection with the network device corresponding to the other cell that it reselects after lowering the priority of cell B, the UE can stay in the other cell to make a call.

[0228] Combine the following Fig. 6A A specific implementation of the above embodiment is introduced.

[0229] See also Fig. 6A , Fig. 6A A flowchart of another communication method provided in an embodiment of the present application. The communication method may include but is not limited to the following steps:

[0230] S201: The UE resides in cell A and makes a call.

[0231] The UE camps on cell A (cell A in this document may be understood as a third cell), and the UE may make a call while camping on cell A.

[0232] S202: The UE sends an A3 MR to network device_1. Network device_1 is the network device corresponding to cell A.

[0233] After measuring and evaluating the neighboring cells of cell A, the UE may send an A3 MR to network device_1.

[0234] In some embodiments of the present application, before the UE executes step S202, the UE may receive a measurement indication sent by the network device 1. The UE may measure and evaluate the neighboring cells of the cell A based on the measurement indication.

[0235] In some embodiments of the present application, the UE may send other types of measurement reports (eg, A5MR) to the network device 1, and the present application does not impose any specific limitation on this.

[0236] Correspondingly, network device_1 can receive the A3 MR sent by the UE.

[0237] S203: Network device_1 sends an RRC connection reconfiguration message to the UE. The RRC connection reconfiguration message is used to instruct the UE to switch the cell it resides in from cell A to cell B.

[0238] After network device 1 receives the A3 MR sent by the UE, it can determine based on the A3 MR that the signal strength of cell B (cell B in this article can be understood as the first cell) is greater and the priority of cell B is higher. Network device 1 can communicate with the network device corresponding to cell B. When network device 1 determines that cell B allows UE access based on the communication process, network device 1 decides to switch (HO) the cell where the UE resides from cell A to cell B, and sends an RRC connection reconfiguration message (RRCConnectionReconfiguration) to the UE. It can be understood that the RRC connection reconfiguration message can be used to instruct the UE to switch the cell where it resides from cell A to cell B.

[0239] Correspondingly, the UE may receive the RRC connection reconfiguration message sent by the network device_1.

[0240] S204: The UE sends an RRC connection reconfiguration complete message to network device_2. Network device_2 is the network device corresponding to cell B.

[0241] After receiving the RRC connection reconfiguration message sent by network device_1, the UE can access cell B according to the configuration carried in the RRC connection reconfiguration message, and after successful access, send an RRC connection reconfiguration complete message (RRCConnectionReconfigurationComplete) to network device_2. In this way, the UE can stay in cell B for calls.

[0242] Correspondingly, network device_2 can receive the RRC connection reconfiguration completion message sent by the UE.

[0243] S205: The UE sends a TAU request to network device_2.

[0244] After the UE switches from cell A to cell B, once it detects that the Tracking Area (TA) changes, it can initiate a TAU process. Specifically, the UE can send a TAU request to the network device corresponding to cell B.

[0245] In some embodiments of the present application, the UE only generates a TAU request and has not yet sent the TAU request. In some embodiments, the UE has sent a TAU request to network device 2, but network device 2 may not receive or correctly parse the TAU request. In the above situation, the UE fails to receive a TAU accept message (TAU accept) from the network side, that is, the UE fails to successfully complete the TAU process.

[0246] S206: Since the RLF is caused by the failure to read the system message corresponding to cell B, the UE performs cell selection and chooses to camp on cell B.

[0247] After the UE switches (HO) from cell A to cell B, the UE resides in cell B for a call. During the process of the UE residing in cell B for a call, the UE fails to read the system message corresponding to cell B (SIB read failure), resulting in RLF, which causes the UE to select a cell. In some embodiments of the present application, since cell B has the highest signal strength, the UE still selects cell B to reside in when performing cell selection. In some embodiments of the present application, the UE can perform cell selection based on previously stored carrier frequency information and cell parameters. Since cell B is the cell with the highest signal strength among several cells corresponding to the carrier frequency information and cell parameters, the UE selects cell B to reside.

[0248] In some embodiments of the present application, cell B is a neighboring cell of cell A.

[0249] It can be understood that the failure to read the system message corresponding to cell B may include that the UE does not receive the system message of cell B, and may also include that the UE receives the system message of cell B but fails to parse it successfully.

[0250] It is understandable that RLF may also be caused by other reasons, which can be referred to above and will not be elaborated here.

[0251] It is understandable that the specific implementation of step S206 can refer to the relevant description of the above step S102, which will not be elaborated here.

[0252] S207: The UE generates an RRC connection re-establishment request and starts the T301 timer. Before the UE sends the RRC connection re-establishment request, it first needs to perform random access.

[0253] After the UE chooses to camp in cell B, it can generate an RRC connection re-establishment request and start the T301 timer. The upper layer module in the UE notifies the lower layer module to prepare to send the RRC connection re-establishment request. Before sending the RRC connection re-establishment request, the UE first needs to perform random access.

[0254] It is understandable that the present application does not limit the specific sequence of the UE generating the RRC connection re-establishment request and starting the T301 timer. The interval between the UE generating the RRC connection re-establishment request and starting the T301 timer is relatively short.

[0255] It is understandable that the relevant description of the T301 timer can be found above and will not be repeated here.

[0256] S208: The UE sends MSG1 to network device_2.

[0257] The first step of random access is to send MSG1. Since the UE resides in cell B, when performing random access, the UE sends MSG1 to network device_2.

[0258] S209: When there is no response to the MSG1 sent by the UE, the UE retransmits MSG1 to the network device_2.

[0259] If there is no response to MSG1 sent by UE to network device 2, UE may retransmit MSG1 to network device 2. In some embodiments of the present application, if there is no response to MSG1 sent by UE to network device 2, UE may continue to retransmit MSG1 to cell B until T301 timer times out.

[0260] It is understandable that the lack of response to MSG1 sent by the UE is only an example of random access failure and should not be regarded as a limitation to the present application. There may be other random access failures. For example, there is no response to MSG3 sent by the UE.

[0261] It is understandable that the specific implementation of steps S207-S209 can refer to the relevant description of the above-mentioned step S103, which will not be elaborated here.

[0262] S210: The T301 timer times out, the UE enters the idle state, and the RRC layer of the modem in the UE notifies the NAS layer that a lower layer failure has occurred. The UE determines that the TAU has failed based on the notification and starts the T3411 timer.

[0263] It can be understood that after the UE starts the T301 timer, it first performs random access in order to subsequently send an RRC connection reestablishment request. If the UE does not receive RRCConnectionReestablishment or RRCConnectionReestablishmentReject within the period defined by the T301 timer, the T301 timer times out, and the UE enters the idle state. At this time, the UE still resides in cell B, but the UE has not established an RRC connection with network device _2. The lower layer module in the UE (e.g., RRC layer) can notify the upper layer module (e.g., NAS layer) that a lower layer failure has occurred. The UE can determine that the TAU has failed based on the notification and start the T3411 timer.

[0264] It can be understood that the T3411 timer is a timer started after a TAU failure. After T3411 times out, the UE initiates the TAU process again. In other words, the period defined by the T3411 timer is equal to the interval length of the UE initiating the TAU process.

[0265] It is understandable that the period defined by the T3411 timer can use the duration specified by the protocol or a custom duration, and the present application does not limit this. In some embodiments of the present application, according to the protocol, the period defined by the T3411 timer is 10 seconds. That is, the duration of the T3411 timer specified by the protocol is 10 seconds. In some other embodiments of the present application, on some chip platforms, the period defined by the T3411 timer is optimized to 2 seconds, instead of using the duration of the T3411 timer specified by the protocol.

[0266] S211: The UE lowers the priority of cell B, performs cell reselection, and chooses to reside in cell A.

[0267] After the UE returns to the idle state, the UE can lower the priority of cell B and perform cell reselection. Since the priority of cell B is lowered, the UE no longer selects cell B (cell B in this article can be understood as the first cell) when performing cell reselection, but selects other cells, which can be called second cells, and the second cell is a cell different from the first cell. For example, the UE can choose to reside in cell A, that is, in one case, the second cell can be cell A, and it can be understood that in another case, the second cell can also be a cell C different from cell B and cell A.

[0268] It can be understood that the specific manner in which the UE reduces the priority of cell B can refer to the relevant description of step S105, which will not be repeated here.

[0269] The cell reselection may include accelerated cell reselection, which may be performed in at least one of the following two ways:

[0270] 1) According to the foregoing, the UE can only start cell reselection after the duration of its stay in the current cell reaches a specified duration (for example, 1 second). In some embodiments of the present application, the UE can reduce the duration of its stay in the original cell before cell reselection, that is, the UE can reduce the above-mentioned specified duration. In other words, the specified duration that the UE needs to stay in the current cell is less than the original specified duration. It is understandable that the original specified duration can be the duration that the UE needs to stay before cell reselection as specified in the relevant protocol.

[0271] 2) In some embodiments of the present application, the UE may reduce the evaluation duration of the target cell during the cell reselection process. That is, the evaluation duration of the target cell by the UE during the cell reselection process may be less than the original evaluation duration. It is understandable that the original evaluation duration may be the evaluation duration before performing cell reselection as specified in the relevant protocol. In one possible implementation, the evaluation duration may refer to Treselection. Treselection is a cell-level parameter. If the target cell continues to meet the cell reselection criteria within the trigger time of Treselection, the UE will perform cell reselection.

[0272] In some embodiments of the present application, after the UE lowers the priority of cell B, the upper layer module may notify the lower layer module (for example, ML1 layer) that the priority of cell B has been lowered. After the lower layer module of the UE learns that the priority of cell B has been lowered, the UE may immediately reselect the cell, that is, start measuring and evaluating the neighboring cells of cell B, without waiting until the residence time on cell B reaches the specified time before reselecting the cell. It can be understood that if Figure 3 As shown, the ML1 layer refers to the PHY layer in the UE's modem.

[0273] In some embodiments of the present application, after the UE lowers the priority of cell B, the upper layer module (for example, the RRC layer) can notify the lower layer module (for example, the ML1 layer) that the priority of cell B has been lowered. After the lower layer module of the UE learns that the priority of cell B has been lowered, the UE can immediately reselect the cell without waiting until the residence time on cell B reaches a specified time length before reselecting the cell. Moreover, during the cell reselection process, the UE can perform cell reselection when the evaluation time length for the target cell reaches the above-mentioned reduced evaluation time length, that is, reselect to the target cell.

[0274] In some embodiments of the present application, after the UE lowers the priority of cell B, the upper layer module (for example, the RRC layer) can notify the lower layer module (for example, the ML1 layer) that the priority of cell B has been lowered. After the lower layer module of the UE learns that the priority of cell B has been lowered, the UE can perform cell reselection when the length of time it stays on cell B reaches the specified time after the above reduction, and the UE can perform cell reselection, that is, reselect to the target cell, when the evaluation time of the target cell during the cell reselection process reaches the evaluation time after the above reduction.

[0275] In some embodiments of the present application, the upper layer module in the UE notifies the lower layer module that the priority of cell B has been reduced, which may specifically include: the upper layer module (e.g., RRC layer) of the UE may send a corresponding message (e.g., RRC deprio req) to the lower layer module (e.g., ML1 layer) to notify the lower layer module that the priority of cell B has been reduced.

[0276] It can be understood that the specific manner in which the UE performs cell reselection can refer to the relevant description of step S105, which will not be repeated here.

[0277] S212: The T3411 timer times out, and the UE re-initiates the TAU process. When the UE initiates the TAU process, it needs to initiate the RRC connection establishment process and start the T300 timer. When the UE initiates the RRC connection establishment process, it first needs to perform random access.

[0278] After the T3411 timer times out, the UE can re-initiate the TAU process. When the UE initiates the TAU process, it first needs to initiate the RRC connection establishment process and start the T300 timer. When the UE initiates the RRC connection establishment process, it first needs to perform random access. It is understandable that the relevant description of the T300 timer can be referred to above and will not be repeated here.

[0279] It is worth noting that, according to step S211 and step S212, the T3411 timer times out only after the UE camps on cell A through cell reselection.

[0280] S213: UE sends MSG1 to network device_1.

[0281] According to the above, when the UE re-initiates the TAU process, it first needs to initiate the RRC connection establishment process, and when initiating the RRC connection establishment process, it first needs to perform random access. The first step of random access is to send MSG1. After the UE re-initiates the TAU process, it can send MSG1 to the network device corresponding to the current resident cell (i.e., network device_1).

[0282] Correspondingly, network device_1 can receive MSG1 sent by UE.

[0283] S214: Network device_1 sends MSG2 to UE.

[0284] It can be understood that after network device_1 receives MSG1 sent by the UE, it can send MSG2 to the UE.

[0285] Correspondingly, the UE can receive MSG2 sent by cell A. It can be understood that after the UE receives MSG2 sent by network device_1, the first and second steps of random access are completed. Next, the UE can establish an RRC connection with network device_1.

[0286] S215: The UE establishes an RRC connection with the network device_1.

[0287] After receiving MSG2 sent by network device 1, UE can establish an RRC connection with network device 1. Specifically, UE can send an RRC connection request (RRCConnectionRequest) to network device 1. After network device 1 receives the RRC connection request sent by UE, it can send an RRC connection establishment message (RRCConnectionSetup) to UE. After UE receives the RRC connection establishment message sent by network device 1, it can send an RRC connection establishment completion message (RRCConnectionSetupComplete) to network device 1. Network device 1 can receive the RRC connection establishment completion message. At this point, UE successfully establishes an RRC connection with network device 1.

[0288] S216: The UE continues the call based on the RRC connection established with the network device_1.

[0289] After the UE establishes an RRC connection with the network device_1, it can stay in the cell A based on the RRC connection and continue the call.

[0290] In some embodiments of the present application, the UE may not perform steps S202 to S204, that is, the UE may not switch (HO) from cell A to cell B. In this case, the UE can still initiate a TAU procedure. However, the TAU procedure initiated by the UE at this time is a periodic TAU, which is different from the TAU initiated due to handover. The relevant description of the periodic TAU can be referred to above and will not be repeated here.

[0291] Combine the following Figure 6B A specific implementation of the above embodiment is introduced.

[0292] See also Figure 6B , Figure 6B A flowchart of another communication method provided in an embodiment of the present application. The communication method may include but is not limited to the following steps:

[0293] S301: The UE resides in cell A and makes a call.

[0294] S302: The UE sends an A3 MR to the network device_1.

[0295] S303: Network device_1 sends an RRC connection reconfiguration message to the UE. The RRC connection reconfiguration message is used to instruct the UE to switch the cell it resides in from cell A to cell B.

[0296] S304: The UE sends an RRC connection reconfiguration completion message to network device_2. Network device_2 is the network device corresponding to cell B.

[0297] S305: The UE sends a TAU request to network device_2.

[0298] S306: Since the RLF is caused by the failure to read the system message corresponding to cell B, the UE performs cell selection and chooses to stay in cell B.

[0299] S307: The UE generates an RRC connection re-establishment request and starts the T301 timer. Before the UE sends the RRC connection re-establishment request, it first needs to perform random access.

[0300] S308: The UE sends MSG1 to network device_2.

[0301] S309: When there is no response to the MSG1 sent by the UE, the UE retransmits MSG1 to the network device_2.

[0302] S310: The T301 timer times out, the UE enters the idle state, and the RRC layer in the modem in the UE notifies the NAS layer that a lower layer failure has occurred. The UE determines that the TAU has failed based on the notification and starts the T3411 timer.

[0303] It can be understood that the specific implementation of steps S301 to S310 can refer to the relevant description of steps S201 to S310, which will not be repeated here.

[0304] S311: The UE performs cell reselection and chooses to continue to stay in cell B.

[0305] S312: T3411 timer times out, and the UE re-initiates the TAU process. When the UE initiates the TAU process, it needs to initiate the RRC connection establishment process and start the T300 timer. When the UE initiates the RRC connection establishment process, it first needs to perform random access.

[0306] S313: UE sends MSG1 to network device_2.

[0307] S314: The T300 timer times out, the UE enters the idle state, and the RRC layer in the UE notifies the NAS layer that a lower layer failure has occurred. The UE determines that the TAU has failed based on the notification and starts the T3411 timer.

[0308] It can be understood that the specific implementation of steps S311 to S314 can refer to the relevant description of steps S10 to S13, which will not be repeated here.

[0309] S315: The UE lowers the priority of cell B, performs cell reselection, and chooses to stay in cell A.

[0310] S316: T3411 timer times out, and the UE re-initiates the TAU process. When the UE initiates the TAU process, it needs to initiate the RRC connection establishment process and start the T300 timer. When the UE initiates the RRC connection establishment process, it first needs to perform random access.

[0311] S317: UE sends MSG1 to network device_1.

[0312] S318: Network device_1 sends MSG2 to UE.

[0313] S319: The UE establishes an RRC connection with network device_1.

[0314] S320: The UE continues the call based on the RRC connection established with the network device_1.

[0315] It can be understood that the specific implementation of steps S315 to S320 can refer to the relevant description of steps S211 to S216, which will not be repeated here.

[0316] Through the above method, the UE can lower the priority of the problem cell at a specific time or under certain circumstances, and reselect the cell based on the lowered priority of the problem cell, which can prevent the UE from always choosing to reside in the problem cell during the cell reselection process, thereby avoiding the UE from dropping calls in call scenarios, and / or avoiding or optimizing the problem of long-term silent calls (such as shortening the silent call time). In addition, the UE can accelerate the reselection after lowering the priority of the problem cell. Compared with the cell reselection process shown in step S10, the cell reselection process shown in step S211 is triggered for a shorter time, and the target cell evaluation time during the cell reselection process is shorter, thereby shortening the duration of the entire cell reselection process, so that the UE can reselect from the problem cell where it originally resides to other cells as soon as possible, thereby shortening the time to successfully establish the RRC connection, thereby reducing the silent problem during the call (such as shortening the silent time during the call).

[0317] In some embodiments of the present application, after lowering the priority of cell B, the UE may also select other cells except cell A and cell B to reside in through cell reselection, which is not limited in the present application.

[0318] It should be noted that the start timing (or cause of start) and timeout timing (or timeout cause) of each timer involved in the embodiments of the present application can be referred to the description in the relevant standard protocol, and understood in combination with the specific scenarios involved in the embodiments of the present application.

[0319] The following is an introduction to the device involved in the embodiments of the present application.

[0320] Figure 7 A schematic diagram of the hardware structure of a UE provided in an embodiment of the present application.

[0321] like Figure 7 As shown, the structure of UE may include: a processor, an external memory interface, an internal memory, a Universal Serial Bus (USB) interface, a charging management module, a power management module, a battery, an antenna 1, an antenna 2, a mobile communication module, a wireless communication module, a sensor module, a button, a motor, an indicator, a camera, a display screen, and a SIM card slot, etc. The audio module may include a speaker, a receiver, a microphone, an earphone interface, etc., and the sensor module may include a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, etc.

[0322] It is to be understood that the structure illustrated in the embodiments of the present application does not constitute a specific limitation on the UE. In other embodiments, the UE may include more or fewer components than shown in the figure, or combine certain components, or split certain components, or arrange the components differently. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0323] The processor may include one or more processing units, for example, the processor may include an application processor (AP), a modem (also called a baseband processor), a graphics processor (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), and / or a neural-network processing unit (NPU). Different processing units may be independent devices or integrated into one or more processors. The processor is the nerve center and command center of the UE. The controller may generate an operation control signal based on the instruction opcode and timing signal to complete the control of fetching and executing instructions.

[0324] The wireless communication function of the UE can be implemented through antenna 1, antenna 2, mobile communication module, wireless communication module, and modem, etc. In some embodiments, the antenna 1 of the UE is coupled with the mobile communication module, and the antenna 2 is coupled with the wireless communication module, so that the UE can communicate with the network and other devices through wireless communication technology.

[0325] The operating system of the UE may adopt a layered architecture, an event-driven architecture, a micro-kernel architecture, a micro-service architecture, or a cloud architecture. The embodiment of the present application takes the Android system of the layered architecture as an example to exemplify the software structure of the UE.

[0326] Figure 8 A schematic diagram of the software structure of a UE provided in an embodiment of the present application.

[0327] The software structure of UE adopts a layered architecture, which divides the software into several layers, each with clear roles and division of labor. The layers communicate with each other through software interfaces. Taking the Android system, 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, namely, the application layer, the application framework layer (Framework), the Android runtime (Android runtime) and the system library, the hardware abstraction layer (HAL) and the system kernel layer (Kernel).

[0328] Among them, the application layer may include a series of application packages. Application packages may include camera, gallery, calendar, call, map, WLAN, Bluetooth, music, video, short message and other APPs. The application layer may also include system UI (system UI). System UI is used to display the UE interface, such as displaying the signal icon corresponding to the SIM card, displaying the call interface, etc. The application framework layer provides an application programming interface (Application Programming Interface, API) and a programming framework for the applications in the application layer. The application framework layer includes some predefined functions. For example, the application framework layer may include a window manager, a content provider, a view system, a phone manager, a resource manager, a notification manager, etc. The phone manager is used to provide call functions for the UE, such as management of call status (including connecting, hanging up, etc.). The phone manager is in Figure 8 The application framework layer may also include a Radio Interface Layer (RIL), and a modem processor (Modem) may exchange information with the telephony through the RIL.

[0329] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A communication method, characterized in that: The method is applied to a terminal device; the method comprises: The terminal equipment resides in the first cell; The terminal device makes a call in the first cell; When a first network abnormality occurs during the call in the first cell, the terminal device selects a cell and chooses to reside in the first cell; The terminal device starts a T301 timer and sends a first message to a first network device, where the first network device is a network device corresponding to the first cell, and the first message is used to request random access; When the T301 timer times out, the terminal device lowers the carrier frequency priority of the first cell; The terminal device performs cell reselection according to the reduced carrier frequency priority of the first cell, and chooses to reside in a second cell, where the second cell is different from the first cell; The terminal device establishes an RRC connection with a second network device, where the second network device is a network device corresponding to the second cell; The terminal device continues the call on the second cell through the established RRC connection.

2. The method according to claim 1, characterized in that After the terminal device lowers the carrier frequency priority of the first cell, the terminal device performs the cell reselection, specifically including: The RRC layer in the terminal device sends a second message to the ML1 layer in the terminal device; the second message is used to instruct the ML1 layer to perform accelerated cell reselection; The ML1 layer in the terminal device receives the second message; The terminal device performs accelerated cell reselection based on the second message.

3. The method according to claim 2, characterized in that The accelerated cell reselection includes: the duration for which the terminal device resides in the original cell before performing cell reselection is less than a first preset duration.

4. The method according to claim 2 or 3, characterized in that The accelerated cell reselection also includes: the evaluation duration of the target cell by the terminal device during the cell reselection process is less than a second preset duration, and the target cell includes the second cell.

5. The method according to claim 4, characterized in that The sum of the duration that the terminal device resides in the original cell and the duration of the evaluation of the target cell is less than the duration of the T3411 timer currently used by the terminal device.

6. The method according to any one of claims 1 to 5, characterized in that The first network abnormality occurs when the terminal device is conducting the call in the first cell, specifically including: when the terminal device is stationed in the first cell and conducting the call, a radio link failure RLF occurs due to a failure to read the system message of the first cell.

7. The method according to any one of claims 1 to 6, characterized in that The first cell is one of at least one neighboring cell of the third cell; before performing the cell selection, the method further includes: The terminal device resides in the third cell to carry out the call; The terminal device switches from the third cell to the first cell; The first network abnormality occurs while the terminal device is residing in the first cell and conducting the call.

8. The method according to claim 7, characterized in that After the terminal device switches from the third cell to reside in the first cell, the method further includes: the terminal device initiating a TAU process; After the terminal device sends the first message to the first network device, the method further includes: after the T301 timer times out, the terminal device starts a T3411 timer; The terminal device establishes an RRC connection with the second network device, specifically including: when the T3411 timer times out, the terminal device re-initiates the TAU process and establishes an RRC connection with the second network device.

9. The method according to claim 7 or 8, characterized in that Among the neighboring cells of the third cell, the signal strength of the first cell is the largest, and the carrier frequency priority of the first cell is the highest.

10. The method according to any one of claims 7 to 9, characterized in that The reduced carrier frequency priority corresponding to the first cell is equal to the minimum value of the priorities corresponding to several neighboring cells of the third cell.

11. A communication method, characterized in that: The method is applied to a terminal device; the method comprises: When a second network abnormality occurs during the process of the terminal device being stationed in the first cell for a call, the terminal device reselects a cell and chooses to station in the first cell; The terminal device starts a T300 timer and sends a first message to a first network device, where the first network device is a network device corresponding to the first cell, and the first message is used to request random access; When the T300 timer times out, the terminal device lowers the carrier frequency priority of the first cell; The terminal device performs cell reselection according to the reduced carrier frequency priority of the first cell, and chooses to reside in a second cell, where the second cell is different from the first cell; The terminal device establishes an RRC connection with a second network device, where the second network device is a network device corresponding to the second cell; The terminal device continues the call on the second cell through the established RRC connection.

12. The method according to claim 11, characterized in that After the terminal device lowers the carrier frequency priority of the first cell, the terminal device performs the cell reselection, specifically including: The RRC layer in the terminal device sends a second message to the ML1 layer in the terminal device; the second message is used to instruct the ML1 layer to perform accelerated cell reselection; The ML1 layer in the terminal device receives the second message; The terminal device performs accelerated cell reselection based on the second message.

13. The method according to claim 12, characterized in that The accelerated cell reselection includes: the duration for which the terminal device resides in the original cell before performing cell reselection is less than a first preset duration.

14. The method according to claim 12 or 13, characterized in that The accelerated cell reselection also includes: the evaluation duration of the target cell by the terminal device during the cell reselection process is less than a second preset duration, and the target cell includes the second cell.

15. The method according to claim 14, characterized in that The sum of the duration that the terminal device resides in the original cell and the duration of the evaluation of the target cell is less than the duration of the T3411 timer currently used by the terminal device.

16. The method according to any one of claims 11 to 15, characterized in that The occurrence of the second network abnormality during the call in the first cell specifically includes: during the call in the first cell, the RRC layer in the terminal device notifies the NAS layer of a bottom layer failure, and determines the TAU failure based on the notification.

17. The method according to claim 16, characterized in that The first cell is one of at least one neighboring cell of the third cell; before performing cell reselection and selecting to reside in the first cell, the method further includes: The terminal device resides in the third cell to carry out the call; The terminal device switches from the third cell to the first cell; When the terminal device resides in the first cell and performs the call, a first network abnormality occurs, and the terminal device performs cell selection and chooses to reside in the second cell; The terminal device starts the T301 timer and sends the first message to the first network device; When the T301 timer times out, the RRC layer in the terminal device notifies the NAS layer that a bottom layer failure has occurred.

18. The method according to claim 17, characterized in that After the terminal device switches from the third cell to reside in the first cell, the method further includes: the terminal device initiating a TAU process; After the terminal device starts the T301 timer and sends the first message to the first network device, the method further includes: when the T301 timer times out, the terminal device starts the T3411 timer; The terminal device starts the T300 timer, specifically including: when the T3411 timer times out, the terminal device re-initiates the TAU process and starts the T300 timer.

19. The method according to any one of claims 11 to 18, characterized in that After the terminal device starts the T300 timer and sends the first message to the first network device, the method further includes: when the T300 timer times out, the terminal device starts the T3411 timer; The terminal device establishes an RRC connection with the second network device, specifically including: when the T3411 timer times out, the terminal device re-initiates the TAU process and establishes an RRC connection with the second network device.

20. The method according to claim 17 or 18, characterized in that Among the neighboring cells of the third cell, the signal strength of the first cell is the largest, and the carrier frequency priority of the first cell is the highest.

21. The method according to claim 17 or 18, characterized in that The reduced carrier frequency priority corresponding to the first cell is equal to the minimum value of the priorities corresponding to several neighboring cells of the third cell.

22. A terminal device, characterized in that: It includes a processor and a memory, and the processor calls and executes a computer program stored in the memory, so that the terminal device implements the method as described in any one of claims 1-10 or 11-21.

23. A chip system, applied to a terminal device, characterized in that: The chip system includes at least one processor and an interface, wherein the interface is used to receive instructions and transmit them to the at least one processor; the at least one processor executes the instructions so that the terminal device executes the method described in any one of claims 1-10 or 11-21.

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