A communication method, comprising: selecting, by a media access control, MAC, entity of a first terminal device , a target side identifier corresponding to a communication type, wherein the communication type comprises unicast communication, multicast communication, or broadcast communication; and the target side identifier comprises a destination layer 2 identifier and/or a destination layer 1 identifier; obtaining, by the MAC entity of the first terminal device , a first sidelink logical channel, LCH, wherein the first sidelink LCH is an LCH having a highest priority among LCHs that correspond to the target side identifier and the communication type and that have data; allocating, by the MAC entity of the first terminal device , a transmission resource to data on the first LCH: encapsulating, by the MAC entity of the first terminal device , LCHs whose target side identifiers and communication types are the same into one transport block, TB; sending, by the first terminal device , assistance information to a network device , wherein the assistance information indicates traffic model information and the communication type; and receiving, by the first terminal device , a scheduling resource from the network device , wherein the scheduling resource comprises a transmission resource of a sidelink used to send traffic data. selecting, by a media access control, MAC, entity of a first terminal device , a target side identifier corresponding to a communication type, wherein the communication type comprises unicast communication, multicast communication, or broadcast communication; and the target side identifier comprises a destination layer 2 identifier and/or a destination layer 1 identifier; obtaining, by the MAC entity of the first terminal device , a first sidelink logical channel, LCH, wherein the first sidelink LCH is an LCH having a highest priority among LCHs that correspond to the target side identifier and the communication type and that have data; allocating, by the MAC entity of the first terminal device , a transmission resource to data on the first LCH: encapsulating, by the MAC entity of the first terminal device , LCHs whose target side identifiers and communication types are the same into one transport block, TB; sending, by the first terminal device , assistance information to a network device , wherein the assistance information indicates traffic model information and the communication type; and receiving, by the first terminal device , a scheduling resource from the network device , wherein the scheduling resource comprises a transmission resource of a sidelink used to send traffic data. encapsulating, by the MAC entity of the first terminal device , LCHs whose target side identifiers and communication types are the same into one transport block, TB; sending, by the first terminal device , assistance information to a network device , wherein the assistance information indicates traffic model information and the communication type; and receiving, by the first terminal device , a scheduling resource from the network device , wherein the scheduling resource comprises a transmission resource of a sidelink used to send traffic data. <EOS>