Method and device used for duplicate data transmission

A communication device used for duplicate data transmission, comprising:

• a transmitter configured to transmit a first indication information;
• or,
• a receiver configured to receive the first indication information;
• wherein the first indication information is used to indicate that a duplicate data transmission function of at least one packet data convergence protocol (PDCP) entity is active or inactive, and/or indicate that a radio link control (RLC) entity used for transmitting duplicate data among a plurality of RLC entities associated with the at least one PDCP entity respectively;
• wherein the first indication information is carried in a media access control control element (MAC CE), the first indication information comprises one byte, the byte comprises a first field and a third field, and the first field comprises a data radio bearer (DRB) identifier (ID) corresponding to the PDCP entity.

A terminal device, comprising:

• a receiver configured to receive first indication information;
• and
• a processor configured to carry out processing for a packet data convergence protocol (PDCP) protocol data unit (PDU) according to the first indication information;
• wherein the first indication information is used to indicate that a duplicate data transmission function of at least one PDCP entity is active or inactive and/or indicate a radio link control (RLC) entity used for transmitting duplicate data among a plurality of RLC entities associated with the at least one PDCP entity respectively;
• wherein the first indication information is carried in a media access control control element (MAC CE), the first indication information comprises one byte, the byte comprises a first field and a third field, and the first field comprises a data radio bearer (DRB) identifier (ID) corresponding to the PDCP entity.