Patent ID: 11064399

Abstract:
Provided are data transmission method and apparatus. The method can includes: establishing an RB on a second cell, receiving, by the first PDCP entity, a packet data convergence protocol service data unit (PDCP SDU) from a core network or a protocol layer above the PDCP entity, and allocating a hyper frame number (HFN) and a sequence number (SN) for the PDCP SDU; processing, by the first PDCP entity, the PDCP SDU according to the 10 SN and HFN to generate a first packet data convergence protocol packet data unit (PDCP PDU); transmitting, by the first PDCP entity, the PDCP SDU as well as the SN and HFN allocated for the PDCP SDU to the second PDCP entity; and processing, by the second PDCP entity, the PDCP SDU according to the SN and HFN transmitted by the first PDCP entity to generate a second PDCP PDU.