Abstract: In a communication method, a first terminal device sends first sidelink information to a second terminal device, and determines that the first sidelink information is successfully transmitted. The first terminal device performs resource reselection on a resource in a first resource set that includes a first group of resources, which includes a first resource. The resources in the first group of resources are consecutive in time domain, and the first resource is for retransmitting the first sidelink information.

Abstract: This application relates to the field of wireless communication, and provides a communication method and apparatus, and a system, to implement continuous data transmission, thereby improving transmission performance. The method includes: A terminal device determines an available resource set SA corresponding to N pieces of data, where SA is located in a resource selection window, N parameter sets correspond to the N pieces of data, data i corresponds to a parameter set i, N is a positive integer greater than 1, i is an integer greater than or equal to 0 and less than N, and the parameter set i includes at least one of the following parameters: a sending priority prioTX,i, a data delay budget PDBi, a frequency domain resource unit LsubCH,i, or a channel access priority class CAPCi; and sends the N pieces of data on a resource in SA.

Abstract: In a communication method, a first terminal determines a common feedback resource and receives first data from a second terminal apparatus on a first time-frequency resource. The first terminal determines a first feedback resource corresponding to the first time-frequency resource used to receive the first data, wherein the first feedback resource belongs to the common feedback resource. The first terminal then sends a first signal on the first feedback resource.

Abstract: Embodiments of this application provide a communication method, a communication apparatus, and a system. In the method, a terminal device obtains channel occupancy time COT, where the COT consists of N time units, and N is an integer greater than or equal to 1; sends first sidelink information to at least two terminal devices in a first time unit in the COT; determines a size of a contention window based on feedback information of the at least two terminal devices for the first sidelink information; and determines, based on the size of the contention window, a random backoff number for performing a channel access procedure, and sends second sidelink information based on a result of the channel access procedure.

Abstract: This application provides a resource reservation method, an apparatus, and a storage medium, applied to the field of communication technologies. The resource reservation method provided in this application includes: A first terminal device receives first indication information from a second terminal device, where the first indication information indicates a first time-frequency resource, and the first time-frequency resource is a resource reserved by the second terminal device. The first terminal device determines, based on one or both of the following, whether to reserve the first time-frequency resource: a first reference signal received power and a quantity of terminal devices that have reserved the first time-frequency resource.

Abstract: This application provides a method for determining a transport block size and an apparatus. The method includes: A first terminal device receives first information from a second terminal device; and determines a TBS of the first information based on a first quantity of frequency domain resource units, where the first quantity n?PRB of frequency domain resource units satisfies n?PRB=N*Mr·NrefPRB, NrefPRB represents a second quantity of frequency domain resource units, and NrefPRB is a positive integer. In this way, determined TBSs respectively corresponding to initial transmission and retransmission of the first information can remain consistent, and failure of HARQ combining of data received a plurality of times can be avoided, thereby improving data decoding accuracy, and improving data decoding efficiency.

Abstract: A communication method and a communication apparatus. The method may include: A first terminal apparatus accesses a first channel. The first terminal apparatus receives first sidelink data on a first resource. The first terminal apparatus sends first sidelink feedback information on a second resource. The first sidelink feedback information is usable to indicate a receiving status of the first sidelink data, the second resource is a resource corresponding to the first resource, and the first resource and the second resource belong to the first channel. A sidelink data resource and a corresponding sidelink feedback information resource are on a same channel.

Abstract: This application provides a communication method and apparatus, so that a terminal device determines a duration of a cyclic prefix extension CPE. The method includes: A first terminal device determines a duration of a cyclic prefix extension CPE based on a priority of sidelink information or a preconfigured duration or parameter, and sends the CPE. In this way, understandings of terminal devices for a manner of determining the duration of the CPE are aligned, to reduce a probability that different terminal devices conflict with each other or block each other, and improve communication efficiency.

Abstract: This application provides a communication method and apparatus, to resolve a problem that a resource waste is caused because a terminal device using a shared resource cannot access a channel. The method may be applied to a sidelink system. The method includes: A first terminal device receives first sidelink control information from at least one second terminal device, where the first sidelink control information indicates a first slot, and the first slot is used by the at least one second terminal device to send sidelink information. When the first terminal device determines that the first slot is within a channel occupancy time, the first terminal device may send first indication information to the at least one second terminal device, where the first indication information indicates a first channel access type.

Abstract: This application relates to the field of wireless communication technologies, and provides a communication method and a communication apparatus. The method includes: A first terminal device performs first channel access, to obtain first COT of a first channel resource, where the first COT includes n first time units and a first time period in an (n+1)th first time unit, the first COT is continuous in time, a length L of the first time period is less than a length of the first time unit, L may be determined based on a channel access priority class p, and n is an integer greater than or equal to 0. The first terminal device sends data to a second terminal device in the first COT by using the first channel resource.

Abstract: A communication method and a communication apparatus, the method including determining, based on a quantity of resource elements (REs) that are in a first time-frequency resource and that are used to transmit first information, a quantity of REs that are in the first time-frequency resource and that are used to transmit data, the first time-frequency resource including a first time unit in time domain and including a data channel resource in frequency domain, where the first information includes at least one of a control channel, a control channel demodulation pilot, a data channel demodulation pilot, second-stage control information, a phase tracking reference signal (PTRS), or a channel state information reference signal (CSI-RS).

Abstract: A communication method and apparatus are provided, and are applicable to fields such as V2X, internet of vehicles, intelligent connected vehicles, assisted driving, and intelligent driving. The method includes: A first terminal device may map first control information to a first transmission resource, and map second information including second control information and data to a second transmission resource and a third transmission resource, and may map the second information to the second transmission resource that does not overlap the first transmission resource in time domain.

Abstract: This application provides a method for determining a transport block size and a communication apparatus, which may be used in systems such as vehicle-to-everything, V2X, and V2V. A receive-end terminal device and a transmit-end terminal device may determine a quantity of encoded symbols based on a symbol length used for sidelink communication in a time unit and a scaling factor, and may further determine a transport block size of a data channel based on the quantity of encoded symbols. Therefore, for all slots used for sidelink communication, a same quantity of encoded symbols can be determined, and a same transport block size can be further determined. In this way, initial transmission or retransmission of a transport block can be performed in each slot used for sidelink communication, to avoid a limitation on selection of a transmission resource and a resulting transmission delay.

Abstract: A sidelink control information sending and receiving method, a terminal apparatus, and a system are provided in this application, and may be applied to fields such as vehicle-to-everything (for example, V2X, LTE-V, or V2V), intelligent driving, and an intelligent connected vehicle. In a scenario in which second-stage SCI is not required in a sidelink communication system, a transmit end apparatus in sidelink communication indicates, by using first-stage SCI, a cyclic redundancy check bit corresponding to the first-stage SCI, or a reference signal used to demodulate the first-stage SCI, that the transmit end apparatus is not to send the second-stage SCI to a receive end apparatus. In this way, the transmit end apparatus may flexibly choose, based on a specific scenario of the sidelink communication, to use 2-stage SCI or 1-stage SCI, to avoid resource waste caused by using the 2-stage SCI in any scenario of the sidelink communication, thereby improving resource utilization efficiency.

Abstract: This application provides example signal transmission method and apparatus. One example method includes sending, by a first terminal device to a second terminal device, indication information indicating a signal transmission resource. Listen before talk (LBT) is performed by the first terminal device before transmission with the second terminal device is performed. Transmission with the second terminal device is performed by the first terminal device according to the indication information.

Abstract: A communication method and apparatus are provided, and relate to the field of communication technologies, to reduce interference to a network device and improve communication reliability when a terminal device performs network device handover. The method may include: A terminal device receives a reference signal from one or more first network devices, and sends a first list to a second network device based on the reference signal. The terminal device receives a reference signal from one or more third network devices by using a first beam, and sends a second list to the second network device based on the reference signal, where the second list indicates the one or more third network devices. The terminal device receives first indication information that is from the second network device and that indicates a target network device, and performs handover to the target network device based on the first indication information.

Abstract: This application provides a power control method and a power control apparatus. The method includes: sending, by a first terminal device, a first signal to a second terminal device at a first transmit power; receiving, by the first terminal device, first information from the second terminal device, where the first information is used to indicate or includes a first received power, and the first received power is a received power of the first signal; determining, by the first terminal device, an estimated value of a path loss between the first terminal device and the second terminal device based on the first transmit power and the first received power. According to this application, power control can be properly performed. This application may be applied to an internet of vehicles, for example, V2X, LTE-V, and V2V, or may be applied to fields such as D2D, intelligent driving, and intelligent connected vehicles.

Abstract: This application provides example reference signal transmission methods, apparatuses, and systems. An example method includes determining a first transmission parameter in at least two transmission parameters, where any two of the at least two transmission parameters are different, and the first transmission parameter is used to determine a first transmission resource for a first reference signal. The first reference signal is sent to a second communication apparatus on the first transmission resource.

Abstract: In a method for resource determination for sidelink communications, a first terminal apparatus determines an available time-frequency resource set in a resource selection window based on resource reservation information of a second terminal apparatus and a first channel occupancy time. The first channel occupancy time is shared by the first terminal apparatus and the second terminal apparatus. When a time-frequency resource occupied by another terminal apparatus during resource selection is excluded, the first terminal apparatus does not need to exclude a time-frequency resource unit reserved by that other terminal apparatus except when it is the second terminal apparatus, to prevent excessive time-frequency resource units from being excluded.

Abstract: This application provides a method for determining a transport block size and a communication apparatus, which may be used in systems such as vehicle-to-everything, V2X, and V2V. A receive-end terminal device and a transmit-end terminal device may determine a quantity of encoded symbols based on a symbol length used for sidelink communication in a time unit and an scaling factor, and may further determine a transport block size of a data channel based on the quantity of encoded symbols. Therefore, for all slots used for sidelink communication, a same quantity of encoded symbols can be determined, and a same transport block size can be further determined.