Communication method and related products

Abstract

The application discloses a communication method and related products, wherein the communication method can include: after a terminal device detects that a first cell meets a reestablishment condition, the terminal device establishes an RRC connection with a second cell. After the RRC connection with the second cell is established, when a first handover command is received, the RRC connection established with the second cell is disconnected. After the RRC connection established with the second cell is disconnected, system information of the first cell is acquired. After the acquisition of the system information of the first cell fails, an RRC connection with a third cell is established. When the number of times that the terminal device fails to acquire the system information reaches a preset number threshold, after the terminal device establishes the RRC connection with the third cell, the terminal device receives a second handover command, disconnects the RRC connection established with the third cell based on the second handover command, and establishes an RRC connection with a fourth cell. The application is implemented, the influence of the time delay is reduced, and the user network experience can be improved.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and related products. Background Technology

[0002] When a user is in a relatively complex network environment, such as when the user is at the edge of multiple cells, the interference between cells is relatively large, and the network environment is complex. Terminal devices may frequently experience a cycle of radio resource control (RRC) connection re-establishment and cell handover. For example, because cell 1 experiences significant inter-cell interference, after the terminal device detects a failure to demodulate downlink information in cell 1, it will re-establish an RRC connection to cell 2. Once the terminal device and cell 2 are in an RRC connection state, the terminal device detects that the signal quality of cell 1 is better than that of cell 2. Therefore, the terminal device may handover back to cell 1 from cell 2. Although the signal quality of cell 1 is better, due to the significant inter-cell interference in cell 1, the terminal device may fail to obtain system information from cell 1. Therefore, the terminal device will re-establish an RRC connection from cell 1 to cell 2. When cell 2 measures that the signal quality of cell 1 is better, it will handover back to cell 1. This cycle of RRC connection re-establishment and cell handover continues, causing network lag for the user. Summary of the Invention

[0003] The purpose of this application is to provide a communication method and related products that can terminate the RRC connection re-establishment-cell handover cycle process in advance, reduce the latency impact caused by RRC connection re-establishment-cell handover cycle anomalies, reduce signaling overhead, and improve the user's network experience.

[0004] In a first aspect, a communication method is provided, the method being applied to a terminal device or a chip of a terminal device, the method comprising:

[0005] After the terminal device detects that the re-establishment conditions are met in the first cell, the terminal device establishes an RRC connection with the second cell, which is different from the first cell.

[0006] After establishing an RRC connection with the second cell, when the terminal device receives the first handover command, the terminal device disconnects the RRC connection established with the second cell. The first handover command is used to instruct the terminal device to hand over to the first cell.

[0007] After disconnecting the RRC connection established with the second cell, the terminal device obtains the system information of the first cell based on the first handover command. The system information may include the MIB and SIB.

[0008] After the terminal device fails to obtain system information from the first cell, it establishes an RRC connection with the third cell, which may be the same as or different from the second cell. Because the terminal device failed to obtain system information from the first cell, it also failed to successfully establish an RRC connection with the first cell, resulting in a cell handover failure. The terminal device can then establish an RRC connection with the third cell through an RRC connection re-establishment procedure.

[0009] When the number of times the terminal device fails to obtain system information reaches a preset threshold, after the terminal device establishes an RRC connection with the third cell, the terminal device receives a second handover command. This second handover command is used to instruct the terminal device to hand over to the fourth cell. The fourth cell and the first cell are different cells, meaning that the terminal device will no longer hand over to the first cell.

[0010] Based on the second handover command, the terminal device disconnects the RRC connection established with the third cell and establishes an RRC connection with the fourth cell.

[0011] Implementing the method of the first aspect, the terminal device establishes an RRC connection with the second cell through the RRC connection re-establishment procedure, and then switches from the second cell to the first cell. Since obtaining system information from the first cell fails, the cell handover also fails, and the terminal device then establishes an RRC connection with the third cell through the RRC connection re-establishment procedure. This embodiment of the application counts the number of times the terminal device fails to obtain system information from the first cell. Each time the terminal device fails to obtain system information from the first cell when switching from another cell to the first cell, the number of failures increases. When the number of failures to obtain system information from the first cell reaches a preset threshold, the terminal device is switched to a fourth cell different from the first cell, thereby prematurely ending the RRC connection re-establishment-cell handover cycle, reducing the latency impact caused by RRC connection re-establishment-cell handover cycle anomalies, reducing signaling overhead, and improving the user's network experience.

[0012] In one possible implementation, the system information includes SIB, and the failure of the terminal device to obtain the system information of the first cell includes:

[0013] The terminal device fails to demodulate the SIB of the first cell, or the terminal device does not receive the SIB of the first cell within a preset time.

[0014] The failure of the terminal device to demodulate the SIB of the first cell can be understood as the terminal device being able to receive the signal carrying the SIB, but failing to demodulate the signal, thus causing the failure to demodulate the SIB of the first cell.

[0015] If the terminal device does not receive the SIB of the first cell within a preset time, it can be understood that the terminal device does not receive the signal carrying the SIB within the preset time.

[0016] Implementing this method provides a scenario where the terminal device fails to obtain system information, thus facilitating the early termination of the RRC connection re-establishment-cell handover cycle when the SIB acquisition fails.

[0017] In one possible implementation, the terminal device detects that the re-establishment conditions are met in the first cell, including:

[0018] When a terminal device fails to obtain system information of the first cell, that is, when the terminal device is in an idle state and fails to obtain system information of the first cell, it is determined that the re-establishment conditions are met in the first cell; for example, when the terminal device switches from another cell to the first cell, before establishing an RRC connection with the first cell, the terminal device fails to obtain system information of the first cell.

[0019] Alternatively, after the terminal device establishes an RRC connection with the first cell, if the terminal device fails to obtain downlink information from the first cell, it is determined that the re-establishment conditions are met in the first cell. The terminal device is in RRC connection state, and it fails to obtain downlink information from the first cell. The downlink information may include downlink data and / or downlink signaling. Therefore, it is determined that the re-establishment conditions are met in the first cell.

[0020] Implementing this method provides the conditions for terminal devices to initiate RRC connection re-establishment in the first cell, thereby facilitating the terminal devices to restore the RRC connection as quickly as possible.

[0021] In one possible implementation, after the terminal device fails to obtain system information from the first cell, but before the terminal device establishes an RRC connection with the third cell, the following is also included:

[0022] The terminal device measures the reference signals of R cells and obtains the reference signal measurement results of R cells, where R cells do not include the first cell and R is a natural number.

[0023] Based on the reference signal measurement results of R cells, the terminal device determines the third cell from the R cells whose reference signal measurement results meet the cell selection criteria.

[0024] If the terminal device fails to obtain system information from the first cell when implementing this method, it indicates that there may be a problem with the first cell. In order to avoid the terminal device selecting the first cell again when re-establishing the RRC connection, the terminal device excludes the reference signal of the first cell when measuring the reference signal. Even if the signal quality of the first cell is relatively good, the terminal device will not select the first cell to initiate the RRC connection re-establishment, thereby reducing the latency of accessing the network.

[0025] In one possible implementation, the terminal device measures reference signals from R cells, including:

[0026] The terminal device measures the reference signals of R cells according to the first blacklist, where the R cells do not include the cells in the first blacklist, and the first blacklist includes the first cell.

[0027] When the terminal device measures the reference signal of R cells, it does so based on the first blacklist. That is, it will not measure cells included in the first blacklist. Since the first cell is in the first blacklist, the terminal device will not measure the reference signal of the first cell, thus avoiding the selection of the first cell as the re-establishment cell during RRC connection re-establishment.

[0028] By implementing this method, a first blacklist is used to record cells that need to be excluded when the terminal device is in an idle state for measuring reference signals. The first blacklist includes the first cell that failed to obtain system information, thereby avoiding the terminal device from initiating RRC connection re-establishment in the first cell when it is in an idle state, and allowing the terminal device to successfully re-establish the RRC connection as soon as possible.

[0029] In one possible implementation, the method further includes:

[0030] When the terminal device fails to obtain system information of the first cell, the terminal device adds the first cell to the first blacklist.

[0031] By implementing this method, when a terminal device fails to obtain system information of the first cell, the terminal device will add the first cell to the first blacklist, thereby preventing the terminal device from selecting the first cell when choosing to re-establish a cell.

[0032] In one possible implementation, after the terminal device establishes an RRC connection with the third cell but before the terminal device receives the second handover command, the following is also included:

[0033] The terminal device measures the reference signals of Q neighboring cells and obtains the reference signal measurement results corresponding to the Q neighboring cells respectively. The Q neighboring cells are the neighboring cells of the third cell. The Q neighboring cells do not include the first cell. Q is a natural number. That is to say, when the terminal device is in RRC connected state, it will also exclude the first cell when measuring the reference signals of neighboring cells.

[0034] The terminal device sends a measurement report, which includes reference signal measurement results of P neighboring cells that satisfy the measurement event. The Q neighboring cells include the P neighboring cells, where P is less than or equal to Q and P is a natural number. Correspondingly, the network device sends a second handover command, which instructs the terminal device to handover to the fourth cell among the P neighboring cells.

[0035] By implementing this method, when the terminal device is in RRC connection state, the first cell that failed to obtain system information will also be excluded. Even if the signal quality of the first cell is very good, the terminal device will not be able to switch to the first cell, thereby avoiding the terminal device from initiating RRC connection re-establishment again due to failure to obtain system information from the first cell.

[0036] In one possible implementation, the terminal device measures reference signals from Q neighboring cells, including:

[0037] The terminal device measures the reference signals of Q neighboring cells according to the second blacklist. The Q neighboring cells do not include the cells in the second blacklist, and the second blacklist includes the first cell.

[0038] The second blacklist records cells that need to be excluded when the terminal device is in connected state and the measurement reference signal is in a connected state. The second blacklist includes the first cell that failed to obtain system information, thereby avoiding the terminal device from selecting the first cell to initiate cell handover when it is in connected state.

[0039] In one possible implementation, the method further includes:

[0040] When the number of times a terminal device fails to obtain system information reaches a preset threshold, the terminal device adds the first cell to the second blacklist.

[0041] If the terminal device fails to obtain system information from the first cell a certain number of times, it will add the first cell to the second blacklist, thereby preventing the terminal device from switching to the first cell again.

[0042] In one possible implementation, the method further includes:

[0043] When a terminal device fails to obtain system information from the first cell, the terminal device increments the count of failed attempts by 1.

[0044] By implementing this method, whenever a terminal device fails to obtain system information from the first cell, the count of failures is incremented by 1, thus allowing for a quick acquisition of the cumulative number of times the terminal device has failed to obtain system information.

[0045] In a second aspect, this application provides a terminal device, the terminal device comprising: one or more processors and a memory; the memory being coupled to the one or more processors, the memory being used to store computer program code, the computer program code including computer instructions, the one or more processors invoking the computer instructions to cause the electronic device to perform a method as described in the first aspect or any possible implementation thereof.

[0046] Thirdly, this application provides a chip system applied to a terminal device, the chip system including one or more processors, the processors being configured to invoke computer instructions to cause the terminal device to perform a method as described in the first aspect or any possible implementation thereof.

[0047] Fourthly, this application provides a computer-readable storage medium including instructions that, when executed on a terminal device, cause the terminal device to perform the method as described in the first aspect or any possible implementation of the first aspect.

[0048] Fifthly, this application provides a computer program product containing instructions that, when the computer program product is run on a terminal device, cause the terminal device to perform the method as described in the first aspect or any possible implementation of the first aspect. Attached Figure Description

[0049] Figure 1 This application provides a schematic diagram of the architecture of a communication system.

[0050] Figure 2 A schematic diagram of an SSB provided for an embodiment of this application;

[0051] Figure 3 A schematic diagram of the RRC re-establishment process provided for the application embodiment;

[0052] Figure 4 This is a schematic diagram of the cell handover process provided in an embodiment of this application;

[0053] Figure 5 A flowchart illustrating an application scenario provided in this application embodiment;

[0054] Figure 6 A flowchart illustrating a communication method provided in an embodiment of this application;

[0055] Figure 7 A flowchart illustrating another application scenario provided by an embodiment of this application;

[0056] Figure 8 A flowchart illustrating another communication method provided in an embodiment of this application;

[0057] Figure 9 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0058] Figure 10 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0059] Figure 11This is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0060] In this embodiment of the application, unless otherwise stated, the character " / " indicates that the preceding and following objects are in an OR relationship. For example, A / B can represent A or B. "AND / OR" describes the relationship between the associated objects, indicating that three relationships can exist. For example, A AND / OR B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0061] It should be noted that the terms "first" and "second" used in the embodiments of this application are used only for distinguishing descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated, nor should they be construed as indicating or implying order.

[0062] In the embodiments of this application, "at least one" refers to one or more items, and "more than one" refers to two or more items. Furthermore, "at least one of the following" or similar expressions refer to any combination of these items, which may include any combination of a single item or a plurality of items. For example, at least one of A, B, or C can represent: A, B, C, A and B, A and C, B and C, or A, B, and C. Each of A, B, and C can be an element itself or a set containing one or more elements.

[0063] In this application, terms such as "exemplary," "in some embodiments," and "in another embodiment" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0064] In the embodiments of this application, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction, their meanings are consistent. Similarly, in the embodiments of this application, "communication" and "transmission" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction, their meanings are consistent. For example, transmission can include sending and / or receiving, and can be a noun or a verb.

[0065] In the embodiments of this application, the term "equal to" can be used in conjunction with "greater than" to apply to technical solutions employing the condition of "greater than", and can also be used in conjunction with "less than" to apply to technical solutions employing the condition of "less than". It should be noted that when "equal to" is used with "greater than", it cannot be used with "less than"; and when "equal to" is used with "less than", it cannot be used with "greater than".

[0066] Please see Figure 1 , Figure 1 This is a schematic diagram of a communication system provided in an embodiment of this application. The communication system may include, but is not limited to, one or more network devices and one or more terminal devices, such as... Figure 1 Taking a network device and a terminal device as an example, where, Figure 1 In this context, network devices, such as base stations, and terminal devices, such as mobile phones, can establish wireless links with network devices for communication. Figure 1 The communication system shown includes, but is not limited to, network equipment and terminal equipment, and may also include other communication equipment. Figure 1 The number and form of the devices shown are for illustrative purposes and do not constitute a limitation on the embodiments of this application.

[0067] In this application embodiment, the terminal device is a device with wireless transceiver capabilities, which may be referred to as a terminal, user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, vehicle-mounted terminal, industrial control terminal, UE unit, UE station, mobile station, remote station, remote terminal, mobile device, wireless communication device, UE agent, or UE device, etc. The terminal device can be fixed or mobile. It should be noted that the terminal device can support at least one wireless communication technology, such as Long Term Evolution (LTE) or New Radio (NR). For example, terminal devices can be mobile phones, tablets, desktop computers, laptops, all-in-one computers, in-vehicle terminals, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, wearable devices, terminals in future mobile communication networks, or terminals in future evolved public land mobile networks (PLMNs), etc. In some embodiments of this application, the terminal may also be a device with transceiver functions, such as a chip system. The chip system may include a chip, and may also include other discrete components.

[0068] In this application embodiment, the network device is a device that provides wireless communication functions for terminal devices, and can also be referred to as an access network device, radio access network (RAN) device, etc. The network device can support at least one wireless communication technology, such as LTE, NR, etc. For example, the network device includes, but is not limited to: next-generation base stations (gNB) in 5th-generation (5G) mobile communication systems, base stations in 6th-generation (6G) mobile communication systems, evolved node B (eNB), radio network controller (RNC), node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home-evolved node B, or home node B, HNB), baseband unit (BBU), transmitting and receiving point (TRP), transmitting point (TP), mobile switching center, etc. Network devices can also be wireless controllers, centralized units (CUs), and / or distributed units (DUs) in cloud radio access network (CRAN) scenarios, or they can be relay stations, access points, vehicle-mounted devices, terminal devices, wearable devices, and network devices in future mobile communications or future evolved PLMNs. In some embodiments, network devices can also be means for providing wireless communication capabilities to terminal devices, such as chip systems. For example, a chip system may include chips, and may also include other discrete devices.

[0069] To facilitate a clear description of the technical solutions in the embodiments of this application, some terms involved in the embodiments of this application will be briefly introduced below.

[0070] 1. Synchronization Signal Block (SSB)

[0071] SSB refers to a resource block that contains synchronization signals and the physical broadcast channel (PBCH). The contents of an SSB typically include the primary synchronization signal (PSS), secondary synchronization signal (SSS), physical broadcast channel (PBCH), and demodulation reference signal (DMRS).

[0072] like Figure 2 The diagram shows a schematic of an SSB. In new radio (NR) systems, an SSB occupies four orthogonal frequency division multiplexing (OFDM) symbols (0-4). PSS and SSS each occupy one symbol in the time domain and 127 resource elements (REs) or subcarriers (56-182) in the frequency domain. Specifically, PSS occupies symbol 0 in the SSB, and SSS occupies symbol 2 in the SSB.

[0073] PBCH consists of the master information block (MIB) and the PBCH payload.

[0074] The MIB is information from higher-level configurations. The MIB carries the most basic information, which involves channel decoding of the Physical Downlink Shared Channel (PDSCH). The UE can only use the parameters in the MIB to continue decoding the data in the PDSCH, including decoding the System Information Block (SIB) information carried in the PDSCH, after decoding the MIB first.

[0075] 2. SIB

[0076] SIBs are used by network devices to transmit important network parameters and configuration information to terminal devices. There are many types of SIBs, such as SIB1, SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, SIB9, SIB10, SIB11, SIB12, and SIB13. Different SIBs carry different parameters and have different functions. Not all of the above SIBs are required. For example, SIB9 is not needed for base stations deployed by operators. Cells continuously broadcast SIBs. The functions of SIB1, SIB2, and SIB3 are illustrated below:

[0077] SIB1: Primarily carries information related to cell access and cell selection, subframe configuration, and scheduling information for other SIBs.

[0078] SIB2: Primarily carries information related to public radio resource configuration, including random access configuration information, uplink frequency information, and Multicast Broadcast Single Frequency Network (MBSFN).

[0079] SIB3: Carries public information related to cell reselection for same-frequency, different-frequency, and cross-system cells.

[0080] 3. RRC reestablishment procedure

[0081] When a terminal device detects that the re-establishment conditions are met, it triggers the RRC re-establishment process. This RRC re-establishment process is used to re-establish the RRC connection of the terminal device to ensure service continuity. The RRC re-establishment process is also called the RRC connection re-establishment process.

[0082] Re-establishment conditions may include at least one of the following:

[0083] A. Signal quality degradation: When the signal quality between the terminal device and the network device falls below a threshold, it may trigger the RRC re-establishment process. Signal quality can be represented by Reference Signal Receiving Power (RSRP) or Reference Signal Receiving Quality (RSRQ).

[0084] B. RRC connection loss: If the RRC connection between the terminal device and the network device is lost, the terminal device will attempt to re-establish the RRC connection, which triggers the RRC re-establishment process. RRC connection loss can also be understood as a wireless link failure.

[0085] C. Mobility Management: When a terminal device moves to a new cell, it may be necessary to re-establish the RRC connection to adapt to the new network environment.

[0086] D. Network configuration changes: When the network configuration changes (such as spectrum adjustment, network device restart, etc.), it may be necessary to re-establish the RRC connection.

[0087] E. User Request: A user's active request to reconnect (such as switching network modes) will also trigger the RRC re-establishment process.

[0088] The following example illustrates the RRC re-establishment process. For ease of description, the network device to which the cell to be re-established belongs in the RRC re-establishment process is referred to as the first network device.

[0089] Please refer to Figure 3 This is a schematic diagram of the RRC re-establishment process provided in the application embodiment.

[0090] 301. The terminal device sends an RRC connection re-establishment request message to the first network device. Correspondingly, the first network device receives the RRC connection re-establishment request message.

[0091] When the terminal device detects that the re-establishment conditions are met, it will perform cell selection, choosing a re-establishment cell that meets the cell selection criteria. The terminal device will then execute the RRC re-establishment procedure with the selected re-establishment cell to re-establish the RRC connection. The cell selection criteria can be choosing the cell with the best signal quality.

[0092] Specifically, the terminal device sends an RRC connection re-establishment request message to the first network device to which the selected re-establishment cell belongs. The RRC connection re-establishment request message includes the identifier of the selected re-establishment cell.

[0093] 302, The first network device sends an RRC connection re-establishment message to the terminal device.

[0094] If the first network device allows the terminal device to re-establish an RRC connection to the requested cell, it sends an RRC connection re-establishment message to the terminal device.

[0095] 303, The terminal device sends an RRC connection re-establishment complete message to the first network device.

[0096] Steps 301-303 enable the terminal device to establish an RRC connection with the re-established cell. It should be noted that, in this application, establishing an RRC connection with the re-established cell can be understood as establishing an RRC connection with the first network device belonging to the re-established cell.

[0097] 4. Cell handover process

[0098] In wireless communication systems, when a terminal device moves from one cell to another or approaches another, cell handover is required to ensure uninterrupted communication. In this embodiment, the source cell refers to the cell that provides service to the terminal device before the handover, and the target cell refers to the cell that provides service to the terminal device after the handover. Information about the target cell (such as its physical cell identifier, frequency information, and random access resource information required for handover) can be sent to the terminal device via a handover command. This handover command is sent from the network device to which the source cell belongs (i.e., the source network device) to the terminal device.

[0099] Cell handover can be intra-cell or inter-cell. Intra-cell handover refers to the source and destination cells belonging to the same network device. Inter-cell handover refers to the source and destination cells belonging to different network devices. This document does not impose any restrictions on these aspects.

[0100] It should be understood that a cell is the coverage area of ​​a network device, with a source cell corresponding to a source network device (e.g., a source base station) and a target cell corresponding to a target network device (e.g., a target base station). It should also be understood that the source cell and the target cell can belong to the same network device, or in other words, the source cell and the target cell can be co-located.

[0101] The following is combined Figure 4 For example, a schematic diagram illustrating the cell handover process performed by a terminal device under the control of network equipment, with the current cell as the source cell and a neighboring cell as the target cell; Figure 4 In this example, inter-site handover means that the source cell and the target cell belong to different network devices. The source cell corresponds to the source network device, and the target cell corresponds to the target network device.

[0102] 401. The terminal device determines that the reference signal measurement results of the current cell and the reference signal measurement results of the neighboring cells satisfy the A3 event.

[0103] The reference signal measurement results for the current cell may include the RSRP and / or RSRQ of the reference signal for the current cell. The reference signal measurement results for neighboring cells may include the RSRP and / or RSRQ of the reference signal for the neighboring cells.

[0104] The A3 event, which is the difference between the reference signal measurement results of the current cell and the reference signal measurement results of the neighboring cell, can be understood as the difference between the reference signal measurement results of the neighboring cell and the reference signal measurement results of the current cell being greater than or equal to a preset threshold.

[0105] 402, the terminal device sends a measurement report to the source network device.

[0106] The source network device is the network device to which the current cell (i.e., the source cell) belongs. The measurement report may include reference signal measurement results for the current cell and reference signal measurement results for at least one neighboring cell that satisfies the A3 event. For example, a terminal device can report the measurement report through the air interface between the terminal device and the source network device.

[0107] 403. The source network device determines, based on the measurement report, that the terminal device should switch to the target cell.

[0108] The source network device can determine the target cell to which it will hand over, based on the reference signal measurement results of the current cell and the reference signal measurement results of at least one neighboring cell that meets the A3 event. The target cell can be a cell among at least one neighboring cell that meets preset conditions, which can be determined by the source network device. For example, the preset conditions may include: the reference signal measurement result of the target cell is greater than or equal to a threshold, and the reference signal measurement result of the target cell is optimal.

[0109] 404, the source network device sends a handover request to the target network device.

[0110] The target network device is the network device belonging to the target cell. The handover request includes the identifier of the terminal device, the resource allocation requirements of the terminal device, and the identifier of the target cell. Specifically, the handover request can be transmitted through a wired or wireless interface between the source network device and the target network device. For example, the handover request can be transmitted through the X2 interface between the source network device and the target network device.

[0111] 405. The target network device sends a handover response to the source network device in response to the handover request.

[0112] The target network device determines whether to allow the terminal device to hand over to the target cell based on the available resources in the target cell and the resource allocation needs of the terminal device. If it allows the terminal device to hand over to the target cell, it sends a handover response to the source network device.

[0113] 406, The source network device sends a handover command to the terminal device.

[0114] The handover command is generated based on the handover response. This handover command instructs the terminal device to hand over to the target cell and includes the identifier of the target cell. The handover command can be transmitted over the air interface between the source network device and the terminal device.

[0115] 407. The terminal device disconnects the RRC connection with the source network device according to the handover command.

[0116] Specifically, when a terminal device receives a handover command, it will disconnect its RRC connection with the source network device.

[0117] It should be noted that, given that the terminal device disconnected the RRC connection with the source network device in step 407, the service between the terminal device and the communication system has been interrupted from step 407 onwards, and the service interruption will continue until the terminal device re-establishes the RRC connection with the communication system, such as if the cell handover is successful, or if the cell handover fails but the subsequent RRC connection is successfully re-established.

[0118] 408. The terminal device establishes an RRC connection with the target network device.

[0119] Before establishing an RRC connection with the target network device, the terminal device receives the target cell's system information. This system information is cell-level, meaning it applies to all terminal devices accessing the target cell. The target cell's system information includes the MIB and SIB. Receiving this information allows the terminal device to understand the target cell's configuration, enabling it to randomly access the target cell and establish an RRC connection. In this application, establishing an RRC connection with the target cell can be understood as establishing an RRC connection with the target network device belonging to the target cell.

[0120] The steps for establishing an RRC connection between a terminal device and a target network device include: the terminal device sending a random access preamble to the target network device; the target network device sending a random access response to the terminal device; and the terminal device completing its own configuration based on the RRC connection reconfiguration information carried in the random access response, and sending an RRC connection reconfiguration complete message to the target network device.

[0121] By executing steps 401-408, the terminal device switches from the source cell to the target cell. After that, the terminal device can continue to provide network services on the target cell, such as restoring the network services between the terminal device and the source cell before the cell handover process was performed.

[0122] When a terminal device is located at the edge of multiple cells, the wireless communication environment is harsh, with poor signal quality and often strong inter-cell interference, which can significantly impact the user's network experience. The following section combines... Figure 5 This document describes a scenario flowchart provided by an embodiment of this application. It should be noted that, for ease of description, the establishment of an RRC connection between the terminal device and the cell can be understood as the establishment of an RRC connection between the terminal device and the network device to which the cell belongs.

[0123] 501. The terminal device detects that the re-establishment conditions are met in the first cell and re-establishes the RRC connection to the second cell.

[0124] If the terminal device detects that the re-establishment conditions are met in the first cell, it will trigger the RRC re-establishment procedure to establish an RRC connection with the second cell. For details regarding the re-establishment conditions, please refer to the description in the foregoing embodiments. The following example illustrates how the terminal device detects that the re-establishment conditions are met in the first cell:

[0125] Example 1: When a terminal device is in RRC connected state with the first cell, but due to significant inter-cell interference in the first cell, the terminal device fails to acquire downlink information from the first cell, and determines that the re-establishment conditions are met, the terminal device can trigger the RRC re-establishment procedure. Downlink information includes downlink data and / or downlink signaling. Failure for the terminal device to acquire downlink information from the first cell can mean that the terminal device receives a signal carrying downlink information but fails to demodulate it (i.e., downlink information demodulation fails), or that the terminal device does not receive a signal carrying downlink information within a preset time.

[0126] Example 2: A terminal device switches from another cell to the first cell, but the cell handover fails during the handover process. The terminal device fails to obtain the system information of the first cell. If the re-establishment conditions are met, the terminal device can trigger the RRC re-establishment procedure. Failure to obtain the system information of the first cell can mean that the terminal device receives a signal carrying system information but fails to demodulate it (i.e., system information demodulation fails), or the terminal device does not receive the signal carrying system information within a preset time. System information may include SIBs. For example, if the terminal device fails to demodulate the SIB of the first cell or does not receive the SIB within the preset time, the terminal device can trigger the RRC re-establishment procedure. Specifically, the SIB can refer to SIB1. If the terminal device fails to demodulate the SIB1 of the first cell or does not receive SIB1 within the preset time, the terminal device can trigger the RRC re-establishment procedure.

[0127] Both Example 1 and Example 2 can be understood as the first cell detecting that the re-establishment conditions are met and triggering the RRC re-establishment process, re-establishing the RRC connection to the second cell.

[0128] When the RRC re-establishment procedure is triggered, the terminal device will perform cell selection, choosing a re-establishment cell that meets the cell selection criteria. For example, the cell selection criteria include selecting the cell with the best signal quality; that is, the terminal device will select the cell with the best signal quality as the re-establishment cell.

[0129] When a terminal device triggers the RRC re-establishment process, it will avoid selecting the first cell as the re-establishment cell. In other words, when selecting a cell, the terminal device can exclude the first cell and will not select it as the re-establishment cell. For ease of description, the selected re-establishment cell in this embodiment is referred to as the second cell, which is different from the first cell.

[0130] The terminal device establishes an RRC connection with the second cell through an RRC re-establishment process. Specifically, the terminal device sends an RRC connection re-establishment request message to the network device belonging to the second cell; the network device belonging to the second cell sends an RRC connection re-establishment message to the terminal device; and the terminal device sends an RRC connection re-establishment completion message to the network device belonging to the second cell. For detailed descriptions, please refer to [link to relevant documentation]. Figure 3 Steps 301-303 of the embodiment will not be repeated here.

[0131] 502, the terminal device has determined to switch from the second cell to the first cell.

[0132] After the terminal device establishes an RRC connection with the second cell, the terminal device is in an RRC connected state. To facilitate mobility management and select a cell with better signal quality, the terminal device measures the reference signal of the second cell to obtain a first measurement result, and measures the reference signal of at least one neighboring cell of the second cell to obtain a second measurement result for each neighboring cell. In this embodiment, the first cell is a neighboring cell of the second cell; that is, the aforementioned at least one neighboring cell includes the first cell.

[0133] The terminal device compares the first measurement result with the second measurement results of each neighboring cell to determine the neighboring cell that satisfies the A3 event. In this embodiment, the signal quality of the first cell is relatively good. Therefore, the terminal device detects that the first cell satisfies the A3 event, that is, the difference between the first measurement result of the first cell and the second measurement result of the second cell is greater than or equal to a preset threshold.

[0134] When a terminal device determines that the second measurement result of the first cell satisfies the A3 event, the terminal device will send a measurement report to the network device to which the second cell belongs. The measurement report may include the second measurement result of the first cell and the first measurement result of the second cell.

[0135] The network equipment belonging to the second cell determines, based on the measurement report, that the terminal device needs to switch to the first cell. The network equipment belonging to the second cell sends a handover request to the network equipment belonging to the first cell. This handover request requests the terminal device to switch to the first cell and may include the identifier of the terminal device, the identifier of the first cell, etc. It is understood that the network equipment belonging to the second cell and the network equipment belonging to the first cell can be different network equipment, or they can be the same network equipment; this application does not impose any limitations.

[0136] If the network device belonging to the first cell allows the terminal device to hand over to the first cell, the network device belonging to the first cell will send a handover response to the network device belonging to the second cell. The network device belonging to the second cell will then send a handover command (i.e., a first handover command) to the terminal device, which instructs the terminal device to hand over to the first cell. This handover command includes the cell identifier of the first cell.

[0137] 503, the terminal device disconnects from the RRC connection of the second cell.

[0138] After receiving the handover command sent by the network device to which the second cell belongs, the terminal device disconnects the RRC connection with the network device to which the second cell belongs according to the handover command.

[0139] 504, the terminal device successfully demodulated the MIB of the first cell, but failed to demodulate the SIB of the first cell.

[0140] Before establishing an RRC connection with the network equipment of the first cell, the terminal device will obtain the system information of the first cell based on the handover command. The system information includes the MIB and SIB. Only by obtaining the system information of the first cell can the terminal device know how the first cell is configured, so as to randomly access the first cell and establish an RRC connection with the first cell.

[0141] If the terminal device fails to obtain system information, the relevant description of the failure can be found in Example 2 of step 501, and will not be repeated here. For example, if the terminal device successfully demodulates the MIB of the first cell, but fails to demodulate the SIB of the first cell, the terminal device will not be able to obtain information such as cell access information and public radio resource configuration, and the terminal device will not be able to establish an RRC connection with the network device to which the first cell belongs.

[0142] The successful demodulation of the MIB in the first cell by the terminal equipment could be due to the MIB being carried in the PBCH of the SSB, which occupies more frequency domain resources and therefore has a higher transmission power. However, the SIB is carried in the PDSCH, which occupies fewer frequency domain resources than the PBCH, resulting in a lower transmission power. Since the terminal equipment is located at the cell edge, inter-cell interference is high, and the PDSCH transmission power is low, this could lead to the terminal equipment failing to demodulate the SIB carried in the PDSCH.

[0143] In some implementations, the failure of the terminal device to demodulate the SIB of the first cell may refer to the failure of the terminal device to demodulate SIB1 of the first cell. Since SIB1 carries the scheduling information of other SIBs, the terminal device is also unable to receive other SIBs of the first cell.

[0144] The terminal device failed to demodulate the SIB of the first cell, so the terminal device did not establish an RRC connection with the first cell. At this time, the terminal device is in an idle state (i.e., IDLE state).

[0145] 505, the terminal device re-establishes the RRC connection with the second cell.

[0146] If a terminal device fails to acquire system information from the first cell, it will trigger an RRC re-establishment procedure. For example, if the terminal device fails to demodulate the SIB of the first cell, it will trigger the RRC re-establishment procedure. The terminal device will select a cell that meets the cell selection criteria as the re-establishment cell; for example, it will select the cell with the best signal quality.

[0147] To avoid the terminal device selecting the first cell as the re-establishment cell, specifically, the terminal device does not measure the reference signal of the first cell when performing cell reference signal measurements. For example, the terminal device measures the reference signals of R cells, excluding the first cell, where R is a natural number. Based on the measurement results of the reference signals of the R cells, the terminal device determines the cell whose reference signal measurement results meet the cell selection criteria. The cell selection criteria could be selecting the cell with the best reference signal measurement results. Since the reference signal of the first cell is not measured at all, the first cell is therefore selected as the re-establishment cell.

[0148] In some implementations, to avoid selecting the first cell as the re-establishment cell, the terminal device can set the first cell as a black cell. For example, the first cell can be added to a first blacklist. When the terminal device performs cell measurement to determine the re-establishment cell, it will not measure cells in the first blacklist. The first blacklist may include cells that the terminal device does not need to measure when performing reference signal measurement in the idle state.

[0149] When a terminal device is in an idle state and is selecting a cell for re-establishment, it can exclude the first cell and will not select the first cell as the cell for re-establishment.

[0150] This embodiment uses the example of the terminal device selecting a second cell for re-establishment. It is understood that the terminal device can also select other cells as the re-establishment cell. For example, the re-establishment cell selected by the terminal device can be called a third cell, which may be the same as the second cell, or the third cell may be different from the second cell. Figure 5 In this example, the terminal device selects the second cell as the new cell for re-establishment.

[0151] The terminal device re-establishes the RRC connection between itself and the second cell through the RRC re-establishment procedure. The specific RRC re-establishment procedure can be found in the aforementioned embodiment. Figure 3 The description will not be repeated here.

[0152] 506, The terminal device has determined to switch from the second cell to the first cell.

[0153] After the terminal device establishes an RRC connection with the second cell, the terminal device is in RRC connected state. The terminal device measures the reference signal of the second cell to obtain a first measurement result, and measures the reference signal of at least one neighboring cell of the second cell to obtain a second measurement result for each neighboring cell.

[0154] The steps in this embodiment can be referred to the description of step 502, and will not be repeated here.

[0155] 507, The terminal device disconnects from the RRC connection of the second cell.

[0156] 508, The terminal device successfully demodulated the MIB of the first cell, but failed to demodulate the SIB of the first cell.

[0157] 509, The terminal device re-establishes the RRC connection with the second cell.

[0158] Steps 507 to 509 in the embodiments of this application can be referred to the description of steps 503 to 505 above, and will not be repeated here.

[0159] As seen in steps 501 to 509 above, the terminal device repeatedly fails to obtain system information from the first cell, re-establishes an RRC connection to the second cell, then switches from the second cell to the first cell, only to fail again to obtain system information from the first cell, re-establish an RRC connection to the second cell, and so on, continuously looping the re-establishment-switching process. It can be understood that after step 509, the process of switching from the second cell to the first cell and re-establishing an RRC connection to the second cell due to failure to obtain system information from the first cell can continue, entering an infinite loop. The terminal device is constantly engaging in signaling interaction, causing signaling overhead and significantly impacting the user's internet access and network experience.

[0160] To address this technical problem, this application proposes a solution whereby, when a terminal device repeatedly triggers an RRC re-establishment process due to failure to acquire system information from the first cell, after re-establishing an RRC connection to the second cell, the terminal device will not consider the first cell as a candidate cell for mobility measurement. In other words, the terminal device will not measure the reference signal of the first cell, and correspondingly, it will not switch from the second cell to the first cell, thus ending the re-establishment-handover cycle, reducing the latency impact of re-establishment-handover cycle anomalies, reducing signaling overhead, and improving the user's network experience. In some implementations, the terminal device may also refrain from considering the first cell as a candidate cell for mobility measurement for a first time period.

[0161] The communication method provided by the embodiments of this application is described below. It should be noted that the various technical solutions (or embodiments) of this application can be implemented independently or in combination based on certain inherent connections. This application does not impose limitations. Furthermore, various terms and definitions between the embodiments can be referenced mutually. In each embodiment of this application, different implementation methods can also be implemented in combination or independently.

[0162] Please refer to Figure 6 This is a flowchart illustrating a communication method provided in an embodiment of this application. It is understood that in a specific implementation, it may include some of the following steps, for example, it may only include step 602.

[0163] 601. When a terminal device fails to obtain system information from the first cell and re-establishes an RRC connection to the second cell, the terminal device will accumulate the number of times it failed to obtain system information.

[0164] If a terminal device fails to obtain system information from the first cell, it will trigger an RRC re-establishment process and establish an RRC connection with the second cell through this process. Each time the terminal device triggers the RRC re-establishment process due to a failure to obtain system information from the first cell, the number of failed attempts to obtain system information is incremented, for example, by 1 each time.

[0165] The failure of a terminal device to acquire system information of the first cell can be understood as the terminal device failing to demodulate the system information of the first cell, or the terminal device failing to receive the system information of the first cell within a preset time. System information may include the MIB and / or SIB; failure to acquire the system information of the first cell can be understood as failure to acquire the MIB and / or the SIB. Optionally, the SIB may refer to SIB1.

[0166] Before the terminal device fails to obtain system information from the first cell and re-establishes an RRC connection to the second cell, the terminal device can perform the following: Figure 5 Steps 501-504 in the document are detailed in [link to document]. Figure 5 Description of the embodiments.

[0167] It is understood that in the embodiments of this application, when the terminal device re-establishes the RRC connection each time it fails to obtain the system information of the first cell, it may re-establish the RRC connection to the same cell each time, such as re-establishing the RRC connection to the second cell each time. Alternatively, it may not be limited to re-establishing the RRC connection to the same cell each time. For example, in step 601, the terminal device re-establishes the RRC connection to the sixth cell, which is different from the second cell.

[0168] One implementation involves re-establishing an RRC connection to the same cell if the terminal device fails to obtain system information from the first cell, and the number of failed system information acquisition attempts (also known as the re-establishment count) is incremented by 1. Another implementation involves triggering an RRC re-establishment process when the terminal device fails to obtain system information from the first cell, and the number of failed system information acquisition attempts (also known as the re-establishment count) is incremented by 1. This means that it is not limited whether the terminal device necessarily re-establishes an RRC connection to the same cell every time.

[0169] Before the terminal device re-establishes an RRC connection to the second cell, it is in an idle state. The terminal device attempts to access the first cell, i.e., attempts to establish an RRC connection with it. If demodulating the SIB1 signal of the first cell fails, the terminal device triggers the RRC re-establishment procedure and selects a cell for re-establishment. For example, the terminal device might choose the cell with the best signal quality as the re-establishment cell. Since the terminal device failed to demodulate the SIB1 signal of the first cell, it will avoid selecting the first cell as the re-establishment cell. Specifically, the terminal device will set the first cell as a blacklisted cell (i.e., add the first cell to the first blacklist). The terminal device will not measure the reference signal of the first cell; therefore, even if the signal quality of the first cell is relatively good, it will not select the first cell as the re-establishment cell. The specific process can be found in [reference needed]. Figure 5 The description of step 505 regarding the terminal device re-establishing the RRC connection with the second cell is provided below. In this embodiment, the terminal device selects the second cell as the re-establishment cell as an example. The terminal device will re-establish the RRC connection with the second cell. The terminal device may also select other cells as the re-establishment cell, and this application does not limit the selection.

[0170] In this embodiment, the terminal device's attempt to access the first cell can occur when the terminal device switches from another cell to the first cell. For example, when the terminal device switches from the second cell to the first cell, it needs to attempt to access the first cell, but due to the failure to demodulate the SIB1 of the first cell, it triggers the re-establishment of RRC connection to the second cell. The terminal device can also re-establish RRC connection to other cells.

[0171] 602. If the number of times the system information acquisition fails reaches N, then the first cell will be set as a black cell.

[0172] In this embodiment, the terminal device re-establishes an RRC connection to the second cell and establishes an RRC connection with the second cell; that is, the terminal device is in an RRC connection state at this time. If the number of times the terminal device fails to obtain system information (also known as the number of re-establishment attempts) reaches N, in order to prevent the terminal device from continuing to switch from the second cell to the first cell, the first cell needs to be set as a black cell. Setting the first cell as a black cell can be understood as adding the first cell to a second blacklist. The cells included in this second blacklist can be cells that need to be excluded when the terminal device is in the RRC connection state and performing reference signal measurements.

[0173] Setting the first cell as a "black cell" by the terminal device can be understood as the terminal device not using the first cell as a candidate cell for mobility measurement. In other words, the terminal device will not measure the reference signal of the first cell. For example, when the terminal device measures the reference signal of Q neighboring cells of the second cell, these Q neighboring cells do not include the first cell. Consequently, the measurement report sent by the terminal device will not include the first cell, where P neighboring cells are included in the Q neighboring cells. Since the terminal device does not measure the reference signal of the first cell, even if the reference signal quality of the first cell is relatively good, the terminal device cannot switch from the second cell to the first cell. This avoids the terminal device triggering the RRC re-establishment process due to failure to obtain system information from the first cell.

[0174] N can be a preset threshold number, and N can be a natural number, for example, N=4. When the number of times the terminal device fails to obtain system information (i.e., the number of re-establishment attempts) reaches N, the first cell is set as a black cell (i.e., the first cell is added to the second blacklist). In some implementations, the terminal device may set the first cell as a black cell (i.e., add the first cell to the second blacklist) after establishing an RRC connection with the second cell.

[0175] In some implementations, the number of times the terminal device failed to acquire system information (i.e., the number of re-establishment attempts) can be an accumulated count within a first time period. For example, the number of times the terminal device failed to acquire system information (i.e., the number of re-establishment attempts) within a first time period is calculated. In one implementation, the start time of the first time period can be the time when the terminal device first detects that the re-establishment conditions are met in the first cell and triggers the RRC re-establishment process. These re-establishment conditions are not limited to the terminal device failing to acquire system information from the first cell. In another implementation, the start time of the first time period is the time when the terminal device fails to acquire system information from the first cell. If the terminal device first detects that the re-establishment conditions are met not due to a failure to acquire system information, the count is not accumulated.

[0176] If the number of failed attempts to acquire system information (i.e., re-establishment attempts) reaches N within the first time period, regardless of whether the end time of the first time period has arrived, the terminal device will set the first cell as a black cell, meaning it will not use the first cell as a candidate cell for mobility measurement, and the accumulated count will be reset to zero. Specifically, when the terminal device detects that the re-establishment conditions are met in the first cell for the first time and triggers the RRC re-establishment procedure, a timer is started. The timer's duration is the first duration. Before the timer expires, each time the terminal device triggers the RRC re-establishment procedure due to a failure to acquire system information from the first cell, the accumulated count is incremented by 1. If the accumulated count reaches N before the timer expires, the first cell is set as a black cell, the timer is reset to zero, and the accumulated count is also reset to zero. If the accumulated count has not reached N when the timer expires, the accumulated count is also reset to zero.

[0177] In some implementations, the terminal device may set the first cell as a black cell for a second duration (i.e., the first cell is placed on a second blacklist for the second duration), during which the terminal device does not consider the first cell as a candidate cell for mobility measurement. The second duration could be, for example, 5 minutes; that is, the terminal device will not measure the reference signal of the first cell for 5 minutes. When the time the first cell has been set as a black cell reaches the second duration, the first cell can continue to be considered as a candidate cell for mobility measurement.

[0178] Specifically, the duration for which the first cell is set as a black cell can be controlled by a timer. Specifically, when the first cell is set as a black cell, a timer is started, and the timer duration is the second duration. When the timer expires, the first cell can continue to be used as a candidate cell for mobility measurement.

[0179] During the second period after setting the first cell as a black cell, the terminal device can measure the reference signals of other neighboring cells of the second cell, as well as the reference signal of the second cell itself. If the measurement results of the reference signal of the second cell and the measurement results of the reference signals of other neighboring cells satisfy the A3 event, a measurement report is sent. The measurement report includes the identifier of the neighboring cell whose measurement results satisfy the A3 event, and the measurement results. The network device will instruct the terminal device to switch to a neighboring cell that satisfies the A3 event. For example, instructing the terminal device to switch to the third cell would be an example. The terminal device would then switch from the second cell to the third cell. This application does not limit the number of cell handovers performed by the terminal device during the second period after setting the first cell as a black cell.

[0180] When the first cell is set as a black cell for a second duration, the terminal device resumes the measurement of the reference signal of the first cell. That is, when the first cell is still used as a candidate cell for mobility measurement, the terminal device can measure the reference signal of the first cell. If the measurement result of the reference signal of the first cell satisfies the A3 event and the network instructs the terminal device to switch to the first cell, then the terminal device can switch to the first cell.

[0181] If the terminal device fails to acquire system information from the first cell again, the RRC re-establishment process will be triggered. At this point, the first cell can be set as a black cell again, meaning it will not be considered as a candidate cell for mobility measurement. The terminal device can set the first cell as a black cell for a third duration, meaning it can choose not to consider the first cell as a candidate cell for mobility measurement for a third duration longer than the second duration. For example, the third duration could be one hour.

[0182] In some implementations, the terminal device may set the first cell as a black cell only after the terminal device has failed to obtain system information of the first cell N times. For details, please refer to the description of the aforementioned embodiments.

[0183] The following is combined Figure 7 This application describes the implementation of the embodiments. Figure 6 The flowchart of the application scenarios following the method described is shown in [the original text]. Figure 7 Taking N=3 as an example, this means that if the number of times the terminal device fails to obtain system information from the first cell (i.e., the number of re-establishment attempts) reaches 3, the first cell will be set as a black cell and will not be used as a cell for mobility measurement. Figure 7 The example given is that each re-establishment involves re-establishing the cell to the second cell. The following section... Figure 7 The following steps will be explained:

[0184] 701. The terminal device detects that the re-establishment conditions are met in the first cell and re-establishes the RRC connection to the second cell.

[0185] 702, The terminal device has determined to switch from the second cell to the first cell.

[0186] 703, The terminal device disconnects from the RRC connection of the second cell.

[0187] 704, The terminal device successfully demodulated the MIB of the first cell, but failed to demodulate the SIB of the first cell.

[0188] 705, The terminal device re-establishes the RRC connection with the second cell.

[0189] Terminal 706 has determined to switch from the second cell to the first cell.

[0190] 707, The terminal device disconnects from the RRC connection of the second cell.

[0191] 708, The terminal device successfully demodulated the MIB of the first cell, but failed to demodulate the SIB of the first cell.

[0192] 709, The terminal device re-establishes the RRC connection with the second cell.

[0193] Steps 701-709 of the embodiments of this application can be referred to. Figure 5 Steps 501-509 of the embodiment will not be repeated here.

[0194] In step 701, the terminal device triggers the RRC re-establishment process for the first time. In step 705, the terminal device triggers the RRC re-establishment process for the second time. In step 709, the terminal device triggers the RRC re-establishment process for the third time. By this point, the terminal device has triggered re-establishment three times from the first cell. In other words, the number of times the terminal device has failed to obtain system information from the first cell has reached the preset threshold of three times. The terminal device can set the first cell as a black cell and not use the first cell as a candidate cell for mobility measurement. That is, step 710 is executed to avoid the terminal device being in a re-establishment-handover loop and to end the loop process in advance.

[0195] 710, The terminal device sets the first cell as a black cell.

[0196] The terminal device sets the first cell as a black cell. Therefore, the terminal device will not measure the reference signal of the first cell. Consequently, even if the reference signal quality of the first cell is relatively good, the terminal device cannot switch to the first cell.

[0197] 711, The terminal device has determined to switch from the second cell to the third cell.

[0198] The terminal device can continue to measure the reference signals of other neighboring cells of the second cell, excluding the first cell. If the signal quality measurement result of the third cell satisfies the A3 event with the signal quality measurement result of the second cell, the network instructs the terminal device to hand over to the third cell. The terminal device can then hand over from the second cell to the third cell. The specific cell handover procedure can be found in the cell handover procedure section of the terminology explanation. Alternatively, when the terminal device receives a handover command from the network device to which the second cell belongs, indicating a handover to the third cell, the terminal device determines to hand over from the second cell to the third cell and executes a cell handover procedure with the second cell as the source cell and the third cell as the target cell.

[0199] 712, The terminal device disconnects from the RRC connection of the second cell.

[0200] 713, The terminal device establishes an RRC connection with the third cell.

[0201] The relevant descriptions of steps 712 and 713 can be found in [reference]. Figure 4 Steps 407 and 408 of the embodiment.

[0202] Depend on Figure 7 The flowchart shown illustrates that terminal devices can end the frequent re-establishment-switching cycle in advance, reducing the latency impact of the cycle, reducing signaling overhead, and improving the user's network experience.

[0203] Please refer to Figure 8 This is a flowchart illustrating another communication method provided in an embodiment of this application. The following describes... Figure 8 Detailed explanation:

[0204] 801. When a terminal device fails to obtain system information of the first cell of the first standard and re-establishes an RRC connection to the second cell of the first standard, the terminal device will accumulate the number of times it failed to obtain system information of the first cell.

[0205] The first standard can be, for example, NR. The terminal device can record the number of times the RRC re-establishment process is triggered due to the failure to obtain system information of the first cell (i.e., the number of times the system information of the first cell is failed to be obtained). Each time the terminal device re-establishes the RRC connection, it can re-establish the connection to a cell of the first standard. That is to say, each time the RRC re-establishment process is triggered, the selected cell for re-establishment is a cell of the first standard.

[0206] One implementation involves the terminal device re-establishing itself in a second cell of the same standard each time it fails to obtain system information from the first cell. In other words, each re-establishment attempt involves the terminal device re-establishing itself in another cell of the same standard (i.e., the second cell). Another implementation involves an RRC re-establishment process triggered each time the terminal device fails to obtain system information from the first cell. However, this does not limit the terminal device to re-establishing itself in the same cell each time, but the selected re-establishment cell is always of the first standard.

[0207] For further details regarding step 801, please refer to [link / reference]. Figure 6 The relevant description of step 601 will not be repeated here.

[0208] 802. If the number of times the system information of the first cell fails to be obtained reaches N, switch from the second cell of the first standard to the fourth cell of the second standard. The first standard and the second standard are different.

[0209] N can be a preset threshold number, and N can be a natural number, for example, N=3. The number of times the system information of the first cell fails to be obtained can also be called the number of re-establishment attempts, which can be the cumulative number within the first time period. Please refer to the relevant description in step 602 for details.

[0210] When the number of re-establishment attempts by the terminal device reaches N, the terminal device can switch from the second cell of the first standard to the fourth cell of the second standard, such as LTE. In other words, the terminal device can switch to cells of other standards. The network transmission performance of the second standard may be lower than that of the first standard.

[0211] The fourth cell in the second standard can be a cell selected by the terminal device based on the measurement results of at least one reference signal from at least one neighboring cell in the second standard. For example, the fourth cell in the second standard is the cell with the best signal quality among the at least one neighboring cell in the second standard. Alternatively, the fourth cell in the second standard can be a cell selected by the network device based on a measurement report reported by the terminal device, and a handover command sent to the terminal device instructing the terminal device to switch to the fourth cell in the second standard. The measurement report includes the measurement results of at least one neighboring cell in the second standard that satisfies the A3 event, as measured by the terminal device.

[0212] In some implementations, before the terminal device switches from the second cell of the first standard to the fourth cell of the second standard, the terminal device can set the first cell as a black cell, i.e., not consider the first cell as a candidate cell for mobility measurement. The terminal device can measure the reference signals of other neighboring cells of the first standard besides the first cell. If the measurement results of the reference signals of no other neighboring cells of the first standard satisfy the A3 event, the terminal device switches from the second cell of the first standard to the fourth cell of the second standard. If the measurement results of the reference signals of other neighboring cells of the first standard satisfy the A3 event, for example, the measurement results of the third cell of the first standard satisfy the A3 event, the terminal device will switch to the third cell of the first standard. If the terminal device fails to receive system information from the third cell, such as failing to demodulate the SIB of the third cell, the terminal device may re-establish itself to other cells of the first standard, such as re-establishing itself to the fifth cell of the first standard. Within the fourth time period, if the terminal device experiences M re-establishment and / or handover times between cells of the first standard, the terminal device can choose to handover or re-establish itself to a cell of the second standard. M times can refer to the sum of the number of re-establishment times and the number of handover times.

[0213] The following describes the communication device provided in the embodiments of this application.

[0214] This application divides the communication device into functional modules according to the above-described method embodiments. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated modules can be implemented in hardware or as software functional modules. It should be noted that the module division in this application is illustrative and represents only one logical functional division; other division methods may be used in actual implementation. The following will combine... Figures 9 to 11 The communication device of the present application embodiment is described in detail.

[0215] Figure 9 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application, such as... Figure 9 As shown, the communication device 1000 can correspondingly implement the functions or steps implemented by the terminal device in the above-described method embodiments.

[0216] The communication device 1000 can correspondingly implement the behavior and functions of the terminal device in the above method embodiments. For example, the communication device 1000 can be a terminal device or a component (e.g., a chip or circuit) applied in the terminal device. The transceiver unit 1100 can, for example, be used to perform all the receiving or sending operations performed by the terminal device in the above method embodiments. The processing unit 1200 is used to perform all operations performed by the terminal device except for the receiving and sending operations.

[0217] The communication device 1000 includes a transceiver unit 1100 and a processing unit 1200.

[0218] Transceiver unit 1100 is used to establish a Radio Resource Control (RRC) connection with a second cell after the processing unit 1200 detects that the re-establishment conditions are met in the first cell. The second cell is different from the first cell.

[0219] After the transceiver unit 1100 establishes an RRC connection with the second cell, when the transceiver unit 1100 receives a first handover command, the processing unit 1200 disconnects the RRC connection established with the second cell. The first handover command is used to instruct the terminal device to hand over to the first cell.

[0220] After the transceiver unit 1100 disconnects the RRC connection established with the second cell, the processing unit 1200 is used to obtain the system information of the first cell based on the first handover command;

[0221] After the processing unit 1200 fails to obtain the system information of the first cell, the transceiver unit 1100 is used to establish an RRC connection with the third cell, which may be the same as or different from the second cell.

[0222] When the number of times the processing unit 1200 fails to acquire the system information reaches a preset threshold, after the transceiver unit 1100 establishes an RRC connection with the third cell, the transceiver unit 1100 is also used to receive a second handover command. The second handover command is used to instruct the terminal device to hand over to the fourth cell, and the fourth cell and the first cell are different cells.

[0223] The transceiver unit 1100 is also used to disconnect the RRC connection established with the third cell and establish an RRC connection with the fourth cell based on the second handover command.

[0224] In one possible implementation, the system information includes a System Information Block (SIB), and the processing unit 1200 fails to acquire the system information of the first cell, specifically including:

[0225] The processing unit 1200 fails to demodulate the SIB of the first cell, or the processing unit 1200 does not receive the SIB of the first cell within a preset time.

[0226] In one possible implementation, the processing unit 1200 detects that the re-establishment condition is met in the first cell, specifically including: when the processing unit 1200 fails to obtain the system information of the first cell, determining that the re-establishment condition is met in the first cell; or, after the transceiver unit 1100 establishes an RRC connection with the first cell, when the processing unit 1200 fails to obtain the downlink information of the first cell, determining that the re-establishment condition is met in the first cell.

[0227] In one possible implementation, after the processing unit 1200 fails to acquire the system information of the first cell, and before the transceiver unit 1100 establishes an RRC connection with the third cell, the processing unit 1200 is further configured to measure the reference signals of R cells and obtain the reference signal measurement results of the R cells, wherein the R cells do not include the first cell and R is a natural number.

[0228] The processing unit 1200 is further configured to determine a third cell from the R cells whose reference signal measurement results satisfy the cell selection criteria, based on the reference signal measurement results of the R cells.

[0229] In one possible implementation, the processing unit 1200 measures reference signals of R cells, specifically including: the processing unit 1200 measures reference signals of R cells according to a first blacklist, wherein the R cells do not include cells in the first blacklist, and the first blacklist includes the first cell.

[0230] In one possible implementation, the processing unit 1200 is further configured to add the first cell to the first blacklist when the terminal device fails to obtain the system information of the first cell.

[0231] In one possible implementation, after the transceiver unit 1100 establishes an RRC connection with the third cell and before the transceiver unit 1100 receives the second handover command, the processing unit 1200 is further configured to measure the reference signals of Q neighboring cells and obtain the reference signal measurement results corresponding to the Q neighboring cells respectively, wherein the Q neighboring cells are the neighboring cells of the third cell, the Q neighboring cells do not include the first cell, and Q is a natural number;

[0232] The transceiver unit 1100 is also used to send a measurement report, which includes reference signal measurement results of P neighboring cells that satisfy the measurement event, wherein the Q neighboring cells include the P neighboring cells, where P is less than or equal to Q, P is a natural number, and the fourth cell is one of the P neighboring cells.

[0233] In one possible implementation, the processing unit 1200 measures the reference signals of Q neighboring cells, specifically including:

[0234] The processing unit 1200 measures the reference signals of Q neighboring cells according to the second blacklist, wherein the Q neighboring cells do not include the cells in the second blacklist, and the second blacklist includes the first cell.

[0235] In one possible implementation, when the number of times the processing unit 1200 fails to acquire the system information reaches a preset threshold, the processing unit 1200 adds the first cell to the second blacklist.

[0236] In one possible implementation, the processing unit 1200 is further configured to increment the number of times the system information acquisition failed when the acquisition of the system information of the first cell fails.

[0237] Figure 9 The specific description and beneficial effects of the illustrated device embodiment can be found in the description of the foregoing method embodiment, and will not be repeated here.

[0238] The terminal device of the embodiments of this application has been described above. The possible product forms of the terminal device are described below. It should be understood that any device possessing the above-described features... Figure 9 Any form of terminal device with the functions described herein falls within the protection scope of the embodiments of this application. It should also be understood that the following description is merely illustrative and does not limit the product form of the terminal device in the embodiments of this application to this specific example.

[0239] In one possible implementation, Figure 10 In the communication device shown, the processing unit 1200 may be one or more processors, and the transceiver unit 1100 may be a transceiver, or the transceiver unit 1100 may also be a transmitting unit and a receiving unit. The transmitting unit may be a transmitter, and the receiving unit may be a receiver. The transmitting unit and the receiving unit are integrated into one device, such as a transceiver. In the embodiments of this application, the processor and the transceiver may be coupled, etc. The connection method between the processor and the transceiver is not limited in the embodiments of this application.

[0240] Figure 10 This is a schematic diagram of another communication device 2000 provided in an embodiment of this application. Figure 10 The communication device mentioned above can be the terminal equipment.

[0241] like Figure 10 As shown, the communication device 2000 includes one or more processors 2200 and transceivers 2100. The transceiver 2100 can implement the functions of the transceiver unit 1100, and the processor 2200 can implement the functions of the processing unit 1200.

[0242] exist Figure 10 In various implementations of the communication apparatus shown, the transceiver may include a receiver for performing a receiving function (or operation) and a transmitter for performing a transmitting function (or operation). The transceiver is also used to communicate with other devices / appliances via a transmission medium.

[0243] Optionally, the communication device 2000 may further include one or more memories 2300 for storing program instructions and / or data. The memory 2300 is coupled to the processor 2200. The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, and can be electrical, mechanical, or other forms, used for information exchange between devices, units, or modules. The processor 2200 may operate in conjunction with the memory 2300. The processor 2200 can execute program instructions stored in the memory 2300.

[0244] This application embodiment does not limit the specific connection medium between the transceiver 2100, processor 2200, and memory 2300. This application embodiment... Figure 10 The transceiver 2100, processor 2200, and memory 2300 are connected via bus 2400. Figure 10 The connections between other components are shown in bold and are for illustrative purposes only, not as limiting information. The bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, Figure 10 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0245] In the embodiments of this application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., and can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules within the processor.

[0246] In this application embodiment, the memory may include, but is not limited to, non-volatile memory such as hard disk drive (HDD) or solid-state drive (SSD), random access memory (RAM), erasable programmable read-only memory (EPROM), read-only memory (ROM), or compact disc read-only memory (CD-ROM), etc. Memory is any storage medium capable of carrying or storing program code in the form of instructions or data structures, and capable of being read and / or written by a computer (such as the communication device shown in this application), but is not limited to this. The memory in this application embodiment may also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0247] The processor 2200 is primarily used for processing communication protocols and data, controlling the entire communication device, executing software programs, and processing software program data. The memory 2300 is primarily used for storing software programs and data. The transceiver 2100 may include control circuitry and an antenna. The control circuitry is primarily used for converting baseband signals to radio frequency signals and processing radio frequency signals. The antenna is primarily used for transmitting and receiving radio frequency signals in the form of electromagnetic waves. Input / output devices, such as touchscreens, displays, and keyboards, are primarily used for receiving user input data and outputting data to the user.

[0248] When the communication device is powered on, the processor 2200 can read the software program in the memory 2300, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be transmitted wirelessly, the processor 2200 performs baseband processing on the data to be transmitted and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit processes the baseband signal and transmits the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor 2200. The processor 2200 converts the baseband signal into data and processes the data.

[0249] In another implementation, the radio frequency circuitry and antenna can be set up independently of the processor performing baseband processing. For example, in a distributed scenario, the radio frequency circuitry and antenna can be arranged remotely, independent of the communication device.

[0250] It is understood that the communication device shown in the embodiments of this application may also have more than Figure 10 This application does not limit the use of other components or other related elements. The methods performed by the processor and transceiver shown above are merely examples; the specific steps performed by the processor and transceiver can be found in the methods described above.

[0251] In another possible implementation Figure 9 In the communication device shown, the processing unit 1200 can be one or more logic circuits, and the transceiver unit 1100 can be an input / output interface, or a communication interface, or an interface circuit, or an interface, etc. Alternatively, the transceiver unit 1100 can also be a transmitting unit and a receiving unit; the transmitting unit can be an output interface, and the receiving unit can be an input interface, integrated into one unit, such as an input / output interface. Figure 11 As shown, Figure 11 The communication device shown includes logic circuitry 3001 and interface 3002. That is, the processing unit 1200 can be implemented using logic circuitry 3001, and the transceiver unit 1100 can be implemented using interface 3002. The logic circuitry 3001 can be a chip, processing circuit, integrated circuit, or system-on-chip (SoC) chip, etc., and the interface 3002 can be a communication interface, input / output interface, pins, etc. For example, Figure 11 The above-mentioned communication device is used as an example of a chip, which includes a logic circuit 3001 and an interface 3002.

[0252] In this embodiment, the logic circuit and the interface can also be coupled to each other. The specific connection method between the logic circuit and the interface is not limited in this embodiment.

[0253] It is understood that the communication device shown in the embodiments of this application can implement the method provided in the embodiments of this application in hardware form or in software form, etc., and the embodiments of this application do not limit it in this way.

[0254] This application also provides a wireless communication system, which includes a network device and a terminal device, and the network device and the terminal device can be used to perform the methods in any of the foregoing embodiments.

[0255] In addition, this application also provides a computer-readable storage medium storing computer code, which, when executed on a computer, causes the computer to perform the operations and / or processes performed by a terminal device or network device in the method provided in this application.

[0256] This application also provides a computer program product, which includes computer code or a computer program. When the computer code or computer program is run on a computer, the operations and / or processes performed by the terminal device or network device in the method provided in this application are executed.

[0257] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, or it may be an electrical, mechanical, or other form of connection.

[0258] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected according to actual needs to achieve the technical effects of the solutions provided in the embodiments of this application.

[0259] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0260] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned readable storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0261] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, include: After the terminal device detects that the re-establishment conditions are met in the first cell, the terminal device establishes a Radio Resource Control (RRC) connection with the second cell, which is different from the first cell. After establishing an RRC connection with the second cell, when the terminal device receives a first handover command, the terminal device disconnects the RRC connection established with the second cell. The first handover command is used to instruct the terminal device to hand over to the first cell. After disconnecting the RRC connection established with the second cell, the terminal device obtains the system information of the first cell based on the first handover command; After the terminal device fails to obtain system information of the first cell, the terminal device establishes an RRC connection with the third cell, which may be the same as or different from the second cell. When the number of times the terminal device fails to obtain the system information reaches a preset threshold, after the terminal device establishes an RRC connection with the third cell, the terminal device receives a second handover command. The second handover command is used to instruct the terminal device to hand over to the fourth cell, which is a different cell from the first cell. Based on the second handover command, the terminal device disconnects the RRC connection established with the third cell and establishes an RRC connection with the fourth cell.

2. The method as described in claim 1, characterized in that, The system information includes a System Information Block (SIB). The failure of the terminal device to obtain the system information of the first cell includes: The terminal device fails to demodulate the SIB of the first cell, or the terminal device does not receive the SIB of the first cell within a preset time.

3. The method as described in claim 1 or 2, characterized in that, The terminal device detects that the re-establishment conditions are met in the first cell, including: When the terminal device fails to obtain system information of the first cell, it is determined that the re-establishment condition is met in the first cell; or, after the terminal device establishes an RRC connection with the first cell, when the terminal device fails to obtain downlink information of the first cell, it is determined that the re-establishment condition is met in the first cell.

4. The method as described in claim 1, characterized in that, After the terminal device fails to obtain system information of the first cell, before the terminal device establishes an RRC connection with the third cell, the following steps are also included: The terminal device measures the reference signals of R cells and obtains the reference signal measurement results of the R cells, wherein the R cells do not include the first cell, and R is a natural number; The terminal device determines a third cell from the R cells whose reference signal measurement results satisfy the cell selection criteria based on the reference signal measurement results of the R cells.

5. The method as described in claim 4, characterized in that, The terminal device measures reference signals from R cells, including: The terminal device measures the reference signals of R cells according to the first blacklist, wherein the R cells do not include the cells in the first blacklist, and the first blacklist includes the first cell.

6. The method as described in claim 5, characterized in that, The method further includes: When the terminal device fails to obtain the system information of the first cell, the terminal device adds the first cell to the first blacklist.

7. The method as described in claim 1, characterized in that, After the terminal device establishes an RRC connection with the third cell, and before the terminal device receives the second handover command, the method further includes: The terminal device measures the reference signals of Q neighboring cells and obtains the reference signal measurement results corresponding to the Q neighboring cells respectively. The Q neighboring cells are the neighboring cells of the third cell. The Q neighboring cells do not include the first cell. Q is a natural number. The terminal device sends a measurement report, which includes reference signal measurement results of P neighboring cells that satisfy the measurement event. The Q neighboring cells include the P neighboring cells, where P is less than or equal to Q, and P is a natural number. The fourth cell is one of the P neighboring cells.

8. The method as described in claim 7, characterized in that, The terminal device measures reference signals from Q neighboring cells, including: The terminal device measures the reference signals of Q neighboring cells according to the second blacklist, wherein the Q neighboring cells do not include the cells in the second blacklist, and the second blacklist includes the first cell.

9. The method as described in claim 8, characterized in that, The method further includes: When the number of times the terminal device fails to obtain system information reaches a preset threshold, the terminal device adds the first cell to the second blacklist.

10. The method as described in claim 1, characterized in that, The method further includes: When the terminal device fails to obtain the system information of the first cell, the terminal device increments the count of failures to obtain the system information by 1.

11. A terminal device, characterized in that, Includes one or more processors and memory; The memory is coupled to the one or more processors, the memory being used to store computer program code, the computer program code including computer instructions, the one or more processors invoking the computer instructions to cause the terminal device to perform the method as described in any one of claims 1-10.

12. A computer storage medium, characterized in that, The computer storage medium is used to store a computer program, which, when executed, performs the method as described in any one of claims 1-10.

13. A computer program product, characterized in that, When the computer program product is run on a terminal device, it performs the method as described in any one of claims 1-10.

14. A chip system, characterized in that, The chip system is applied to a terminal device, and the chip system includes one or more processors, the processors being used to invoke computer instructions to cause the terminal device to perform the method as described in any one of claims 1-10.

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