Abstract: This application provides a network selection method, a network device, and a terminal device. The network selection method mainly includes: A first network device sends a first message to a terminal device. The first message includes a message that indicates the terminal device to measure a cell of a first-type network, the first-type network is a high-priority network selectable for the terminal device, and a network provided by the first network device does not belong to the first-type network.

Abstract: Example mapping methods and apparatus are described. One example method includes determining a message type of an uplink signaling message by an integrated access and backhaul node. The integrated access and backhaul node maps the uplink signaling message to a corresponding backhaul radio link control (BH RLC) based on an uplink mapping relationship from an integrated access and backhaul donor centralized unit and the message type. The uplink signaling message is sent to a parent node of the integrated access and backhaul node.

Abstract: The present disclosure discloses example downlink buffer status feedback methods and apparatuses. One example method includes determining first information by a first node, where the first information indicates a downlink buffer status of a first bearer between the first node and a parent node of the first node. The first information is sent by the first node to a second node, where the first node is a relay node in a wireless relay communications system, and the second node is a parent node of the first node.

Abstract: This application provides a method of determining an association between logical channel groups, including: The first backhaul node receives a first buffer status report from a first device, where the first buffer status report is used to determine uplink buffer statuses of one or more first logical channel groups of a MAC entity corresponding to the first backhaul node and the first device. The first backhaul node determines, based on the first logical channel group(s) and a first mapping relationship, one or more second logical channel groups associated with the first logical channel group(s), where a second device is a parent node of the first backhaul node, and the first mapping relationship includes a mapping relationship between the first logical channel group(s) and the second logical channel group(s) of a MAC entity corresponding to the first backhaul node and the second device.

Abstract: Embodiments of the present disclosure provide a data transmission method and apparatus. The method includes: receiving, by user equipment UE, first synchronization source configuration information on a first carrier; determining, a first synchronization source based on the first synchronization source configuration information; determining that synchronization with the first synchronization source fails; determining a second synchronization source and a transmission resource; and transmitting data on a second carrier using the determined transmission resource and based on the second synchronization source, where the first synchronization source is used to provide the UE with a synchronization clock required for transmitting the data on the second carrier, and a frequency of the first carrier is different from a frequency of the second carrier.

Abstract: A random access method and device. The method includes receiving, by user equipment, a radio resource control (RRC) connection reconfiguration message from a first network device, the RRC connection reconfiguration message indicating a primary serving cell of the second network device for a user equipment, an active uplink bandwidth part (BWP) in the primary serving cell, and an active downlink BWP in the primary serving cell, the RRC connection reconfiguration message includes an uplink BWP identifier indicating the active uplink BWP and a downlink BWP identifier indicating the active downlink BWP, the uplink BWP identifier corresponds to the active uplink BWP, the downlink BWP identifier corresponds to the active downlink BWP, and initiating, by the user equipment, a random access procedure to the second network device on the active uplink BWP and the active downlink BWP.

Abstract: A communication method and an apparatus are provided. The method includes: receiving, by a terminal device, a first command sent by a network device, wherein the first command carries a first identifier, and is used to activate a first bandwidth part (BWP) indicated by the first identifier, and the first BWP is a BWP on a first component carrier (CC); and ignoring the first command when the terminal device does not support the first BWP and a second BWP being in an active state at the same time, wherein the second BWP is a BWP in the active state on a second CC, and the second CC is different from the first CC. According to the application, the terminal device may determine, based on a capability of the terminal device, to ignore an improper command, to optimize a problem of switching an active BWP in a carrier aggregation scenario.

Abstract: This application provides a network selection method, a network device, and a terminal device. The network selection method mainly includes: A first network device sends a first message to a terminal device. The first message includes a message that indicates the terminal device to measure a cell of a first-type network, the first-type network is a high-priority network selectable for the terminal device, and a network provided by the first network device does not belong to the first-type network.

Abstract: An entity establishment processing method and an apparatus are provided. The processing method includes: A terminal side device receives first indication information from a first network side device, where the first indication information is used to trigger reestablishment of a first PDCP entity of the terminal side device. When a first bearer corresponding to the first PDCP entity is not a radio bearer used to perform duplication transmission between the terminal side device and a core network side device, in a process in which the terminal side device reestablishes the first PDCP entity based on the first indication information, the terminal side device sets a parameter of the first PDCP entity to an initial value.

Abstract: This application provides a data transmission method and an apparatus. The method includes that an integrated access and backhaul (IAB) donor distributed unit receives downlink data and service attribute information of downlink data that are sent by an IAB donor centralized unit. The IAB donor distributed unit maps the downlink data to a corresponding backhaul radio link control channel (BH RLC) channel based on the service attribute information of the downlink data or based on the service attribute information of the downlink data and access IAB node address information of the downlink data, and sends the downlink data to a next-hop IAB node.

Abstract: This application provides a communication method and a communications device. The method includes: A first device receives a first message sent by a second device. The first message is used to indicate a bearer configuration of a bearer of the first device and an initial status of the bearer configuration, and the bearer configuration includes a first bearer configuration and/or a second bearer configuration. The first device determines the bearer configuration and the initial status of the bearer configuration based on the first message. According to the technical solutions in embodiments of this application, a bearer configuration of a terminal device and an initial status of the bearer configuration of the terminal can be indicated. Because both the bearer configuration of a bearer of the terminal and the initial status of the bearer configuration of the terminal are indicated, communication efficiency is improved.

Abstract: The present disclosure provides communications methods and apparatuses. One method includes: receiving, by a first communication node, first indication information from a second integrated access and backhaul (IAB) node, wherein the first indication information indicates that a radio link failure (RLF) occurs on a backhaul (BH) link on a first communication path between the first communication node and a second communication node, wherein the first communication node is a terminal device or a first IAB node, and wherein the second IAB node is on the first communication path, and reporting, by the first communication node, second indication information through a second communication path between the first communication node and the second communication node, wherein the second indication information indicates that the RLF occurs on the BH link on the first communication path.

Abstract: Embodiments of the present disclosure provide a data transmission method and apparatus. The method includes: receiving, by user equipment UE, first synchronization source configuration information on a first carrier; determining, a first synchronization source based on the first synchronization source configuration information; determining that synchronization with the first synchronization source fails; determining a second synchronization source and a transmission resource; and transmitting data on a second carrier using the determined transmission resource and based on the second synchronization source, where the first synchronization source is used to provide the UE with a synchronization clock required for transmitting the data on the second carrier, and a frequency of the first carrier is different from a frequency of the second carrier.

Abstract: This application provides a communication method and a communication apparatus. The method includes: A target access network device determines that a first terminal device is handed over from a source access network device to the target access network device; and sends first information to the first terminal device, where the first information indicates a first packet header compression context, and the first packet header compression context is for compressing or decompressing a packet header of a data packet. In this application, the target access network device sends, to the first terminal device, the first information indicating the first packet header compression context, so that in a handover scenario, the first terminal device can correctly decompress a subsequently received data packet with a compressed packet header. This helps improve communication reliability.

Abstract: This application relates to a communication method and device. The communication method includes: receiving first signaling, where the first signaling indicates to deactivate that a first logical channel; and determining, depending on whether a logical channel in an activated state and the first logical channel belong to a same MAC entity, whether an association relationship between a carrier and the logical channel in the activated state applies, where the first logical channel and the logical channel in the activated state belong to a same radio bearer, and a PDCP duplication transmission function is configured for the radio bearer. According to the method provided in embodiments of this application, after a logical channel is deactivated, carriers that should be used for a remaining logical channel can be known, so that a terminal device can perform a correct operation.

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: In accordance with an embodiment, a communication method applied to a first node includes: receiving first information from a second node, wherein the first information comprises an available space size in a first buffer space of the second node, the first buffer space is for buffering a data packet that is to be transmitted through a first path, the first path is a primary path for transmitting the data packet, and the second node is a next-hop node of the first node on the primary path; and in response to the available space size in the first buffer space being less than or equal to a first threshold, determining to transmit the data packet through a third node, wherein the third node is a next-hop node of the first node on a backup path for transmitting the data packet.

Abstract: The present disclosure relates to methods applied to an integrated access and backhaul (IAB) node. An example method includes receiving configuration information for setup of a distributed unit (DU) part of the IAB node and determining, based on a manner of receiving the configuration information, that a master node of the IAB node or a secondary node of the IAB node is a donor node of the IAB node.

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.