Hybrid ARQ for IP packet transmission

This paper proposes and analyses the performance of a hybrid selective repeat (SR)/multi copy (MC) automatic repeat request (ARQ) scheme to transmit fragmented Internet protocol (IP) packets. The ARQ scheme works in SR mode till the last IP packet fragment is transmitted. If a packet is negatively acknowledged after the last fragment is transmitted then the system goes in MC mode. In MC mode multiple copies of the erroneous fragment are transmitted. After all fragments are received without error the system goes back to SR mode. Performance of the ARQ is evaluated in terms of BER, IP packet size and fragmentation size. Performance results are also obtained using Bose Chandhuri Hocquenghem (BCH) error correction codes. A 18 percent throughput improvement is achieved at BER 10/sup -3/ over the conventional scheme.