Patent ID: 8483061

Claim:
A method of performing layer 2 processing on a circuit chip, the method comprising: retrieving data packets from an external memory to the circuit chip for transmission; processing the data packets by a layer 2 processor to generate Radio Link Control (RLC) Protocol Data Units (PDUs), storing the RLC PDUs prior to transmission in an on-chip memory co-located with the layer 2 processor on the circuit chip; upon a request to retransmit an RLC PDU, selectively reading: i. the RLC PDU to be retransmitted from the on-chip memory; or ii. a data packet comprising the RLC PDU to be retransmitted from the external memory and re-generating the RLC PDU to be retransmitted from the data packet read from the external memory, dependent on whether or not the RLC PDU to be retransmitted belongs to a data packet that has been completely transmitted in a single layer 1 transport unit. and initiating a retransmission of the RLC PDU from at least one of: i. the on-chi memo if the RLC PDU to be retransmitted has been sent in a first layer 1 transport unit and belongs to an RLC Service Data Unit (SDU) comprising at least one further RLC PDU that has been sent in a second layer 1 transport unit, and ii. from the external memory if the RLC PDU to be retransmitted belongs to an RLC SDU that has been completely transmitted in the single layer 1 transport unit.