System information transmission method and apparatus

An information transmission method performed by one or more second terminal devices in a system comprising a first terminal device and the one or more second terminal devices, the first terminal device establishes a sidelink (SL) connection to each second terminal device, each second terminal device obtains a network service of a target cell through the first terminal device, the target cell is a serving cell of the first terminal device, wherein the method comprises:

• sending, by one or more second terminal devices, a first request message to a first terminal device, wherein the first request message is used to request to obtain M system information blocks (SIBs) or system information (SI) messages of a target cell, wherein M is an integer;
• and
• receiving, by the one or more second terminal devices, a second message sent by the first terminal device in a broadcast or multicast manner, wherein the second message comprises the M SIBs or SI messages, the M SIBs or SI messages correspond to N destination identifiers, the N destination identifiers corresponding to the M SIBs or SI messages determined by parsing content of the first request message to determine the M SIBs or SI messages required by all or some of the one or more second terminal devices, the second message comprises the corresponding destination identifiers, N is an integer greater than or equal to 1, and N≤M, and wherein:
• each of the M SIBs or SI messages corresponds to a different destination identifier, and the different destination identifier indicates the first terminal device to send the M SIBs or SI messages in the multicast manner;
• or
• K SIBs or SI messages of the M SIBs or SI messages correspond to one same destination identifier, 1≤K<M, and the one same destination identifier indicates the first terminal device to send the M SIBs or SI messages in the multicast manner.

An apparatus, comprising:

• at least one processor;
• and
• a memory storing programming, the programming including instructions that, when executed by the at least one processor, cause the apparatus to perform:
• receiving a first request message from one or more second terminal devices, wherein the first request message is used to request to obtain M system information blocks (SIBs) or system information (SI) messages of a target cell, wherein M is an integer;
• determining N destination identifiers corresponding to the M SIBs or SI messages, wherein N is an integer greater than or equal to 1, and N≤M, and wherein determining by the first terminal device, N destination identifiers corresponding to the M SIBs or SI messages comprises:
• after receiving the first request message, parsing content of the first request message to determine the M SIBs or SI messages required by all of the one or more second terminal devices;
• then determining, by the first terminal device, that each of the M SIBs or SI messages corresponds to a different destination identifier, wherein the different destination identifier indicates to send the M SIBs or SI messages in a multicast manner;
• or
• then determining, by the first terminal device, that K SIBs or SI messages of the M SIBs or SI messages correspond to one same destination identifier, wherein 1≤K<M, and the destination identifier indicates to send the M SIBs or SI messages in the multicast manner;
• and
• sending a second message to the one or more second terminal devices in the multicast manner, wherein the second message comprises the M SIBs or SI messages, and the second message comprises the corresponding destination identifiers.