Patent ID: 8730969

Claim:
A method of retransmitting data unit, performed by an Acknowledged Mode Radio Link Control (AM RLC) entity of a transmitter, in wireless communication system, the method comprising: transmitting, by the transmitter, a data unit to a AM RLC entity of a receiver; determining whether the data unit is considered for retransmission; setting a counter associated with the data unit when the data unit is considered for retransmission; and delivering an indication to an upper layer of the AM RLC entity when a value of the counter reaches a maximum retransmission value, wherein the data unit includes an Acknowledged Mode Data (AMD) Protocol Data Unit (PDU) or a portion of a AMD PDU, wherein the setting the counter associated with the data unit includes: setting the counter to an initial value when the data unit is considered for retransmission for a first time, and incrementing the counter when the data unit is considered for retransmission after a first time, and wherein the AM RLC entity only sets the counter if: the AM RLC entity receives a discard indication for a Radio Link Control Service Data Unit (RLC SDU) from a Packet Data Convergence Protocol (PDCP) entity, and at least one segment of the RLC SDU is mapped to the AMD PDU or the portion of the AMD PDU.