Patent ID: 8472379

Claim:
A mobile station configured to transmit and receive packets, each provided with a sequence number, on a Packet Data Convergence Protocol (PDCP) layer to and from a radio base station, comprising: a buffer monitor/sequence number assigner configured to discard a packet on the PDCP layer in a transmission buffer of the PDCP layer, when a buffered time of the packet on the PDCP layer in the transmission buffer exceeds a predetermined threshold; wherein the buffer monitor/sequence number assigner is configured to assign a sequence number to the discarded packet on the PDCP layer, when a mode of an Radio Link Control (RLC) layer is an unacknowledged mode; and the buffer monitor/sequence number assigner is configured not to assign a sequence number to the discarded packet on the PDCP layer, when the mode of the RLC layer is an acknowledged mode.