Abstract: Terminal apparatus identification methods and apparatuses are described. An access stratum (AS) of a first communications apparatus sends first information to an AS of a second communications apparatus. The AS of the second terminal apparatus may identify a leader terminal apparatus based on the first information, so as to implement perception of the leader terminal.

Abstract: In a communication method, a first user equipment sends first data to second user equipment over a sidelink (SL); and if the first user equipment does not receive first feedback information, the first user equipment initializes a first counter, or keeps a count value of the first counter unchanged, where the first feedback information indicates whether the second user equipment successfully receives the first data and the first counter is used for RLF detection.

Abstract: A communication method includes indicating, by a first device to a second device, that the first device is configured in a first mode, wherein a current protocol version of the first device is incompatible with a current protocol version of the second device. The communication method further includes receiving, by the first device, protocol information from the second device, wherein the protocol information is useable by the first device to update the current protocol version of the first device. The communication method further includes updating, by the first device, the current protocol version of the first device based on the protocol information.

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: Embodiments of the present disclosure relate to the field of communications technologies, and in particular, to a communication method and a device. Second user equipment executes some tasks required for communication between first user equipment and a network device, and the first user equipment properly communicates with the second user equipment. In this way, energy consumption of the first user equipment required for communication with the network device can be reduced, thereby prolonging a standby time and improving user experience.

Abstract: This application relates to the field of communication technologies, and provides a sidelink transmission method and apparatus, to resolve a problem of reliability of sidelink multicast or broadcast data transmission. The method includes: determining, by a communication device, that at least one of the following conditions is met: a first timer corresponding to sidelink discontinuous reception DRX is not running, a second timer corresponding to DRX is not running, or a third timer corresponding to a first sidelink SL process is running; and scheduling, by the communication device, retransmission corresponding to the first SL process, where the first timer, the second timer, and the third timer may be timers related to DRX information, and the third timer may be further a timer related to the SL process.

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 includes sending, by a first device, first information to a second device. The first information includes N capability parameter sets different from a first capability. The N capability parameter sets are supported by the first device at a time when the first device requests capability adjustment from the second device. The first capability is a maximum capability supported by the first device, and N is an integer greater than or equal to 1.

Abstract: A communication method includes storing, by a terminal device, a first parameter usable by the terminal device in a first mode. The communication method further includes failing, by the terminal device, to access a network device, failing to register with the network device, or failing to be capable of camping on a network of the network device. The communication method further includes performing, by the terminal device, access to the network device in the first mode by the first parameter.

Abstract: A communication method includes obtaining first information. The first information includes a first reference signal configuration information set. The first reference signal configuration information set includes one or more first pieces of reference signal configuration information. The one or more first pieces of reference signal configuration information are requested by a terminal device on-demand. The communication method also includes sending second information to a first network device. The second information includes a second reference signal configuration information set requested by the terminal device. The second reference signal configuration information set includes one or more second pieces of reference signal configuration information.

Abstract: A terminal device obtains a first group of parameters corresponding to a first mode. A network device obtains a second group of parameters corresponding to the first mode, where the first group of parameters correspond to the second group of parameters. When a compatibility problem exists between the terminal device and the network device, the terminal device initiates initial access to the network device based on the first group of parameters, and the network device accepts, based on the second group of parameters, the initial access initiated by the terminal device.

Abstract: A cell selection or reselection method includes that a terminal device obtains first information that corresponds to a first cell and that is not specific to a frequency band or a frequency. When a first condition that corresponds to the first information and that is used to determine whether the terminal device can access the first cell is not met, the terminal device is allowed to select or reselect a cell on a same frequency as the first cell.

Abstract: Embodiments of this application provide a discontinuous reception control method, the method is as follows: receiving first control information transmitted in a unicast manner, where the first control information is for scheduling first data transmitted in a multicast manner; and performing, by a communication apparatus, any one or more of the following actions: starting or restarting a first timer, where the first timer indicates duration after newly transmitted control information or newly transmitted data is scheduled; stopping a second timer, or starting or restarting a second timer, where the second timer indicates duration in which the communication apparatus receives retransmitted data; and starting or restarting a third timer, where the third timer indicates waiting duration before the communication apparatus receives the retransmitted data, where the timers are timers corresponding to DRX associated with multicast.

Abstract: This disclosure describes a random access method, an apparatus, and a system, to resolve an RNTI conflict during random access of different types of terminal devices or different types of services. An example method includes: sending a random access preamble to a network device on a first random access channel occasion RO, where the first RO corresponds to a first device type and/or a first service type; and listening to physical downlink control information PDCCH scrambled by using a first radio network temporary identifier RNTI associated with the first RO. Calculation of the first RNTI is associated with the first device type and/or the first service type.

Abstract: A communication method and apparatus are provided. One example method includes: receiving a first message from a network device, wherein the first message comprises first indication information, and the first indication information indicates to allow a request to adjust a capability mode of a terminal device to one capability mode in M capability modes; and the one capability mode in the M capability modes corresponds to a group of capability information sets, and M is an integer greater than 0; and determining the M capability modes based on the first message.

Abstract: An information reporting method includes receiving, by a terminal device, a capability inquiry message from a first network device, and obtaining first release information of a second network device. The information reporting method also includes determining, by the terminal device, first capability information of the terminal device based on the first release information. The information reporting method further includes sending, by the terminal device, the first capability information to the first network device.

Abstract: Embodiments of this application provide a power headroom reporting method, an apparatus, and a system, to resolve a problem that a level mismatch currently exists between calculation of a Type 3 power headroom and reporting of the Type 3 power headroom. The method includes: A terminal device determines a power headroom corresponding to one or more reference signal resource sets in each of one or more cells, where the one or more cells are cells that are among cells participating in positioning of the terminal device and that require the terminal device to report the power headroom; and the terminal device sends power headroom information to a network device, where the power headroom information includes the power headroom corresponding to the one or more reference signal resource sets in each of the one or more cells.

Abstract: Embodiments of this application provide a resource preemption method, an apparatus, and a system, to reduce a quantity of times of frequent resource preemption, and improve resource security. In one example, a first terminal device obtains a first time interval and a second time interval, and preempts or determines not to preempt a first resource according to a first preset rule. The first resource is a resource reserved by a second terminal device or a resource reserved for a first service to be transmitted by the first terminal device. The first time interval is a time interval related to the first resource. The second time interval is used to indicate a preemption forbidden time. The first preset rule is determined based on the first time interval and the second time interval.

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 apparatus. A sidelink resource is determined that meets a quality of service requirement of to-be-transmitted data to improve data transmission efficiency in a 4G system, a 5G system, and/or a future communication system, for example, a 6G system. A first terminal device receives delay information, determines a first packet delay budget, and determines a resource for transmitting data on a sidelink. The delay information indicates a packet delay budget that data transmission is to meet, the first packet delay budget is a packet delay budget that is to be met in response to data being transmitted on the sidelink, and the sidelink is a link for transmitting data between the first terminal device and a second terminal device.