An error control protocol that automatically initiates a request to repeat the transmission of any packet or frame not acknowledged as received correctly, in other words, to retransmit the last errored or lost frame or packet and any transmitted afterwards. Incremental redundancy (IR), also known as Hybrid ARQ II, is an enhanced ARQ technique employed in EGPRS (Enhanced General Packet Radio System), the packet-switched mode of Enhanced Data rates for GSM Evolution (EDGE) cellular radio networks. See also EDGE, EGPRS, error control, frame, IR, packet, and protocol.