Abstract: A timer processing method includes: receiving, by a terminal device, a first message sent by a network device, and starting or restarting a timer based on a scrambling identifier of the first message, wherein the timer is a timer used by the terminal device to switch from an active downlink BWP to a default downlink BWP, or is a timer used by the terminal device to activate a default downlink BWP and deactivate an active downlink BWP; or if an active BWP pair of the terminal device is not a default BWP pair, starting or restarting, by the terminal device, a timer based on a scrambling identifier of the first message, wherein the timer is a timer used by the terminal device to switch from the active BWP pair to the default BWP pair, or is a timer used by the terminal device to activate the default BWP pair.

Abstract: A communication method and a device are described to compress and decompress a data packet including an ethernet header to reduce radio transmission resources of an air interface. The communication method includes determining, by a sending device, a to-be-sent data packet. The to-be-sent data packet is a data packet including an ethernet header. The method further includes determining, by the sending device, a field to be compressed in the header of the to-be-sent data packet; and compressing, by the sending device, the header of the to-be-sent data packet according to a preset method. The preset method includes: removing the field to be compressed from the header of the data packet, or replacing the field to be compressed with a corresponding short field; and sending, by the sending device, a data packet obtained after the compressing.

Abstract: This application provides a session setup method and an apparatus. The method includes: when an access network device obtains a first session setup request from a first core network device, if the access network device determines that a multicast broadcast service corresponding to a first session that the first session request requests to set up is the same as a multicast broadcast service corresponding to a second session, determining that an air interface resource corresponding to the first session is the same as an air interface resource corresponding to the second session, where the first session setup request is used to request to set up the first session corresponding to a first multicast broadcast service, and the second session is a session set up between the access network device and a second core network device.

Abstract: The present disclosure provides a carrier aggregation capability reporting apparatus and method, so as to prevent a user equipment (UE) from repeatedly reporting capability information corresponding to a carrier combination supported by the UE, and reduce waste of signaling resources used for reporting. The method includes: determining, by the UE, information about a carrier combination supported by the UE and information about a sub-combination that is of the carrier combination and that is supported by the UE; and reporting, by the UE to a base station, the determined information about the carrier combination supported by the UE and the determined information about the sub-combination that is of the carrier combination and that is supported by the UE.

Abstract: A communication method and apparatus are provided. The method includes: A first node determines a sending time point of a second PDCP PDU based on first sending status information from a second node, where the first sending status information is associated with a first PDCP PDU, so that the first node can adjust the sending time point of the second PDCP PDU based on a sending situation of the first PDCP PDU, to avoid too many packet losses caused when a MAC PDU of the second PDCP PDU is not completely sent in a timely manner due to splitting and concatenation, so as to improve reliability of a synchronous data transmission mechanism in an NR system, and improve resource utilization.

Abstract: A terminal device determines that local first system information is abnormal in the case of any of the following: a quantity of times of sending first signaling is greater than or equal to a first preset threshold within first preset duration; a time length in which a first service is unavailable is greater than or equal to a second preset threshold; a change trend of a tag value of a same system information block is abnormal; or a quantity of changes in a tag value of a same system information block is greater than or equal to a third preset threshold within second preset duration. The terminal device receives, from an access network device, second system information that is used to update the local first system information. Therefore, the terminal device can determine as soon as possible whether the terminal device is being attacked by a rogue base station.

Abstract: Embodiments of this application disclose a service paging method, a related device, and a system. The method may include: When a core network device and an access network device perform multicast and broadcast service paging on a terminal device, update and/or security processing are/is performed on an identifier used to identify a multicast and broadcast service each time. The terminal device can determine the multicast and broadcast service based on the identifier on which update and/or security processing are/is performed. In embodiments of this application, the identifier on which update and/or security processing are/is performed is used during multicast and broadcast service paging. In this way, difficulty of tracking the multicast and broadcast service by an eavesdropper can be increased, to improve security of the multicast and broadcast service.

Abstract: Embodiments of this application provide for a communication method and a related communication apparatus. A second access network device receives a first message from a first access network device, where the first message indicates whether a first state of a multicast broadcast service (MBS) session is activated or deactivated. The second access network device sends a first acknowledgment message corresponding to the first message to the first access network device. In this solution, the first message indicates the first state of the MBS session, and the second access network device may determine, based on the first state, whether to request a core network to establish a user plane (UP) tunnel. If the first state of the MBS session is activated, the second access network device may be triggered to newly establish a UP tunnel, to ensure a normal transmission of the MBS in a handover process.

Abstract: Embodiments of this application disclose a communication method and a related communication apparatus. In a dual connectivity scenario, user equipment (UE) establishes a dual connection to a master radio access network node (MN) and a secondary radio access network node (SN). When the MN requests the SN to provide a multicast broadcast service (MBS) for the UE of the MN, the MN sends a first request to the SN, where the first request includes a first identifier corresponding to the MBS. After receiving the first request, the SN sends a first response to the MN, where the first response indicates that the SN agrees to provide the MBS service for the UE. In this way, MBS service data is sent to the UE through the SN in the dual connectivity scenario.

Abstract: Data transmission methods and apparatuses, relate to the field of communications technologies are described. In an example method, a distributed unit (DU) receives a first packet data convergence protocol (PDCP) packet data unit (PDU) from a central unit (CU), where the first PDCP PDU carries data of a multicast broadcast service (MBS). The DU sends the first PDCP PDU to at least two terminal devices. The DU sends a status report to the CU, where the status report indicates results of sending the first PDCP PDU to the at least two terminal devices.

Abstract: This application provides a data processing method and apparatus, and a computer storage medium. When a PDCP entity over a UM DRB is re-established, or when a cell handover occurs and the PDCP entity over a UM DRB uses a key used before the handover, the PDCP entity determines a first SDU, where the first SDU is an SDU that is associated with a sequence number by the PDCP entity but whose corresponding data has not been transmitted through an air interface; and delivers a PDU corresponding to the first SDU to an RLC entity. Data corresponding to the first SDU is redelivered, to avoid a data packet loss caused by preprocessing of the PDCP entity.

Abstract: This application provides a communication method and apparatus. The method includes: A terminal device receives configuration information from a network device, where the configuration information is used to configure a first carrier or a first carrier group. The terminal device may send first information to the network device, where the first information is used to request to suppress activation of the first carrier or the first carrier group.

Abstract: This application provides a data transmission method and an apparatus, to resolve a problem of high multicast transmission control signaling overheads. The method includes: receiving first multicast data using a multicast based semi-persistent scheduling SPS transmission; receiving first downlink control information DCI, where the first DCI is scrambled by a configured scheduling radio network temporary identifier CS-RNTI; and receiving first data based on the first DCI, where the first data is retransmitted data of the first multicast data.

Abstract: A method includes: performing, by a terminal device, data transmission based on a configuration parameter of a currently activated first bandwidth part BWP, where the configuration parameter of the first BWP includes at least one of a first resource offset, a first bandwidth, and a first subcarrier spacing; determining, by the terminal device, a first random access resource and a second configuration parameter for random access, where the second configuration parameter includes at least one of a second resource offset, a second bandwidth, and a second subcarrier spacing; sending, by the terminal device, a random access request to the network device on the first random access resource; and receiving, by the terminal device, a random access response based on the second configuration parameter, where the random access response is sent by the network device based on the random access request.

Abstract: A communication method and a communication apparatus. The method includes: an access network device receives first indication information from a core network device, where the first indication information indicates a value of a count of a first data packet, and the count includes a hyper frame number and a packet data convergence protocol sequence number. The access network device determines the value of the count of the first data packet based on the first indication information. The access network device determines, based on the first indication information received from the core network device, the value of the count corresponding to the data packet, to implement synchronization of values of packet data convergence protocol sequence numbers and synchronization of values of hyper frame numbers between different access network devices.

Abstract: A method includes: determining, by a terminal device, a carrier aggregation capability and baseband capabilities of the terminal device, where the carrier aggregation capability includes a quantity of carriers and a bandwidth of a carrier in a carrier aggregation group supported by the terminal device, and the baseband capabilities include a multiple-input multiple-output (MIMO) capability; sending, by the terminal device, the information of the carrier aggregation capability and the baseband capabilities to a network device; and receiving, by the terminal device, configuration information.

Abstract: A communication method and a communication apparatus. In the method, a terminal device can obtain first resource information according to a preset rule or from a network device, where the first resource information includes at least one of frequency domain position information, a cyclic prefix, or a subcarrier spacing; and receive a multicast broadcast service in a radio access control (RRC) idle state or an RRC inactive state based on the first resource information. According to the method, a resource used when the terminal device receives the multicast broadcast service in the RRC idle state or the RRC inactive state can be determined, so that the terminal device can receive the multicast broadcast service in the RRC idle state or the RRC inactive state.

Abstract: A secondary cell activation method and apparatus relating to the communications field are described herein. The method may include sending, by an access network device, an activation command to a terminal device, where the activation command indicates activating a secondary cell. The method may also include sending, by the access network device, first configuration information of a first reference signal to the terminal device. Furthermore, the method may include sending, by the access network device, the first reference signal to the terminal device according to the first configuration information, where the first reference signal is used to obtain a channel measurement result of the secondary cell. According to secondary cell activation methods described herein, a flexible and efficient secondary cell activation mechanism can be provided, so as to improve secondary cell activation efficiency.

Abstract: Disclosed are a signaling optimization method and device, to resolve a problem of heavy signaling overheads and long data transmission delay when a user equipment (UE) accesses a network side. The method includes: receiving, by the UE, configuration information sent by a first network side device, where the configuration information includes a list, and the list is a cell list or a base station list; and entering, by the UE, an intermediate state according to the configuration information, where the intermediate state means that: when the UE stores context information of the UE, if the UE moves and a cell movement range falls within a coverage area of a cell or a base station included in the list, the UE performs cell reselection according to the list. Embodiments of the present disclosure are applicable to optimization of signaling transmission between the UE and a network side.

Abstract: A method includes: determining, by a communications device, information about a target beam; determining a target monitoring occasion based on the information about the target beam and a mapping relationship between information about a beam and a monitoring occasion, where the target monitoring occasion is in a system information window, and the system information window is used for OSI; and monitoring downlink control information in the target monitoring occasion. This application is applicable to a process of information transmission between a network device and the communications device.