Abstract: This application provides a communication method and apparatus. The method includes: A terminal device receives first information sent by a first base station, where the first information includes a first timing advance of a second base station, or the first information includes a parameter used by the terminal device to obtain the first timing advance of the second base station, and the first timing advance is a timing advance used in a process of data transmission with the second base station; and the terminal device obtains the first timing advance of the second base station based on the first information.

Abstract: This application provides a communication method and apparatus. The method includes: A terminal device receives first indication information, where the first indication information includes a common timing advance of at least one candidate cell, and the first indication information is used to inform the terminal device that the at least one candidate cell is in a handover allowed state; and the terminal device sends a random access preamble to a target candidate cell based on a first timing advance, where the target candidate cell is one of the at least one candidate cell, and the first timing advance is a common timing advance of the target candidate cell. According to the method provided in this application, the UE can send the preamble more accurately in a handover scenario.

Abstract: A communication method and apparatus are disclosed. After receiving, from a source network device, a first message that enables a terminal device to handover from the source network device to a target network device, maintaining data transmission with the source network device; and sending a first report in response to subsequently detecting that a connection between the terminal device and the source network device fails. The first report includes first indication information used to determine whether the connection between the terminal device and the source network device fails before the terminal device accesses the target network device. In this way, the network device identifies, based on the information, a potential handover scenario that has a problem, so that a handover parameter is better adjusted or handover is more properly triggered, thereby improving a handover success rate of the terminal device.

Abstract: A method includes receiving a first message from a first master node. The first message includes an identifier of a first candidate primary secondary cell (PSCell) or an identifier of first configuration information of the first candidate PSCell. The first candidate PSCell is included in both a first PSCell list and a second PSCell list. Alternatively, the first message includes delta configuration information of a second candidate PSCell in the second PSCell list. The first configuration information of the first candidate PSCell includes an addition/change condition and a configuration of the first candidate PSCell. The first PSCell list includes one or more candidate PSCells configured by the first master node for a terminal. The second PSCell list includes one or more candidate PSCells configured by a second master node for the terminal. The method also includes adding a target PSCell or changing from an original PSCell to the target PSCell.

Abstract: Embodiments of this application provide a communication method, apparatus, and system. The method includes: determining, based on area configuration information of a first cell of a network device and location information of a terminal device, a first sub-area corresponding to the terminal device, where the area configuration information indicates information about a plurality of sub-areas corresponding to the first cell, and the plurality of sub-areas include the first sub-area; and obtaining satellite ephemeris information corresponding to the first sub-area. In the foregoing solution, the sub-area is introduced, and the terminal device only needs to obtain the satellite ephemeris information corresponding to the sub-area in which the terminal device is located. This reduces an amount of satellite ephemeris information obtained by the terminal device, and therefore can reduce overheads of the terminal device.

Abstract: A handover method and a communication apparatus. A terminal device receives a first message, where the first message includes information about N candidate cells, the N candidate cells include N1 candidate cells and N2 candidate cells, the N1 candidate cells include a cell for which no conditional handover CHO execution condition information is configured, the N2 candidate cells include a cell for which the CHO execution condition information is configured, N and N2 are integers greater than 1 or equal to 1, and N1 is an integer greater than 0 or equal to 0. In a process of attempting to hand over from the source cell to the target cell, the terminal device maintains an RRC connection and/or data transmission with the source cell. Therefore, handover reliability is improved, a handover latency is reduced, and overall system performance is improved.

Abstract: This application provides a group handover method. The method includes: A first terminal device receives first information from a first network device, where the first information indicates a first resource, the first resource is for carrying fourth information, the fourth information is cell handover information of a plurality of terminal devices, and the first terminal device is one of the plurality of terminal devices; and the first terminal device receives the fourth information on the first resource. This can reduce signaling overheads caused by cell handover of a plurality of users and improve resource utilization.

Abstract: Embodiments of this application provide a communication method and a communication apparatus, and relate to the communication field. The method includes: A first network device receives a first report from a terminal device, where the first report includes first information, and the first information indicates that the terminal device passively falls back from 2-step random access to 4-step random access, or actively falls back from 2-step random access to 4-step random access. The first network device performs processing based on the first report.

Abstract: This application relates to the field of communications technologies, and discloses a communication method and a communication apparatus, to reduce service delay due to uplink data cannot be directly sent by a terminal when the terminal is in an inactive state. The method in this application includes: receiving a first message from a first access network device; then releasing or suspending a configured dedicated signaling radio bearer SRB and resetting protocol entities corresponding to a configured data radio bearer DRB. The first message is used to indicate to a terminal to enter a radio resource control (RRC) inactive state, and the first message carries an identifier of the terminal in the radio resource control (RRC) inactive state and radio access network notification area (RNA) information.

Abstract: This application relates to the field of communication technologies, and discloses a communication method and apparatus. The terminal device determines, depending on a second information from a network device and whether a terminal device supports uplink service transmission through a second network device, a parameter used to perform cell selection or cell reselection.

Abstract: This application provides a handover method and apparatus. The handover method includes: A terminal device sends path information used to determine a first cell to a network device; and the terminal device receives conditional handover CHO configuration information that is corresponding to the first cell and that is sent by the network device, and determines a target cell based on the CHO configuration information corresponding to the first cell. According to the technical solutions provided in this application, a handover success rate can be improved when the terminal device performs cell handover.

Abstract: This application provides a radio resource management measurement method and apparatus. A network device sends measurement configuration information to a terminal device, where the measurement configuration information carries a first threshold; and the terminal device determines, based on a value relationship between a detection value and the first threshold, and signal quality of at least one neighboring cell, whether to report a measurement report. When performing RRM measurement, the terminal device can determine, based on a relationship between the first threshold and signal quality of a serving cell and/or a quantity of detected cells, and the signal quality of the at least one neighboring cell, whether to report the measurement report. This can prevent the terminal device from reporting the measurement report frequently, and avoid a case in which the terminal device does not report the measurement report in a timely manner, so that a measurement mechanism is more appropriate.

Abstract: A communication method and apparatus, the method including receiving, by a first access network device, a first message from a terminal in a radio resource control (RRC) inactive state, where the first message requests to resume an RRC connection or to perform a radio access network-based notification area update (RNAU), and sending, by the first access network device, a first request message to a second access network device, where the first request message includes a cell radio network temporary identifier allocated by the first access network device for the terminal, and the second access network device is an access network device that retains a context of the terminal, and there is a control plane link of the terminal between the second access network device and a core network.

Abstract: Embodiments of this application disclose a paging collision processing method and a related apparatus. The method includes: When a terminal device detects that a paging occasion of the terminal device in a first camped cell collides with a paging occasion of the terminal device in a second camped cell, the terminal device may determine a first paging parameter, and may send first information including the first paging parameter to a first network device corresponding to the first camped cell. The first network device sends second information including a second paging parameter to the terminal device. The terminal device determines a second paging occasion of a first identity module card of the terminal device in the first camped cell based on the second paging parameter in the received second information. The terminal device monitors a paging message in the first camped cell on the second paging occasion.

Abstract: Embodiments of this application provide a cell reselection method and system, and an apparatus. The method includes: receiving reselection configuration information from a network device, where the reselection configuration information includes reselection trigger information, the reselection trigger information is used to trigger measurement for cell reselection, and the reselection trigger information includes reselection trigger time information or reselection trigger indication information; and performing measurement for cell reselection based on the reselection configuration information. In embodiments of this application, the reselection configuration information including the reselection trigger information is introduced.

Abstract: This disclosure provides communication methods, communication apparatuses, and communication systems. One example method includes: A terminal device supporting a first subscriber identity and a second subscriber identity determines to deregister the first subscriber identity from a first network. Then, the terminal device sends a deregistration request message to an access network device by using the second subscriber identity, where the deregistration request message is used to request to deregister the first subscriber identity form the first network, and the deregistration request message carries an identifier of the first subscriber identity.

Abstract: This application provides a paging method and apparatus. The method includes: A first device receives a first paging message, where the first paging message includes a first list, and the first list includes an area identifier of at least one cell. The first device determines a first cell, where an area identifier of the first cell at a first moment is different from an area identifier of the first cell at a second moment, the first moment is a current moment, and the second moment is earlier than the first moment. When the area identifier of the first cell at the first moment does not belong to the first list, the first device stops paging a terminal device in the first cell. According to the foregoing technical solutions, the first device may effectively page the terminal device, to reduce signaling overheads of the first device, and save power.

Abstract: This application provides a communication method, a communications apparatus, and a communications system. The method includes: A terminal device generates first indication information, where the first indication information is used to indicate a plurality of non-public networks, the plurality of non-public networks include a first non-public network, and the first non-public network is a network that the terminal device requests to access; and the terminal device sends the first indication information to an access network device.

Abstract: A mobility optimization method and a related apparatus are provided. The method includes: determining connection failure information; and sending the connection failure information and an identifier of a first cell to a first network device by using a radio resource control (RRC) message, wherein the identifier of the first cell comprises an identifier of a cell from which a reconfiguration message or a handover command message received by the terminal device comes or an identifier of a cell in which a connection failure occurs, wherein the connection failure information is in a form of a container in the RRC message and the identifier of the first cell is outside the container.

Abstract: A communication method, apparatus, and system, the method including receiving first indication information from a first network device, where the first indication information is requests a terminal device to report first information, and reporting the first information to the first network device, where the first information includes related information in a conditional handover procedure.