A hybrid ARQ/FEC scheme for noisy ATM network links

ATM is accepted to be the transport technique for B-ISDN. ATM networks suffer from cell loss due to buffer overflow and/or corruption of the cell header because of channel errors. Originally, ATM networks were designed to work over fiber links that have extremely low bit error rates (BER). For noisy ATM links, such as wireless links, the probability of cell loss due to errors in the header increases significantly. Most applications require the lost cells to be retransmitted using some ARQ protocol, thus causing the system throughput to fall down. This paper proposes and analyzes a hybrid ARQ/FEC scheme for noisy ATM links. The proposed FEC code is a two-dimensional single-parity check (2D-SPC) code. This code is simple to encode and decode. A tight upper bound on the performance of the code is derived. For ARQ, a selective-repeat protocol with two retransmission strategies, all-cell retransmission and lost-cell retransmission, is implemented. Results of the analysis show that the proposed hybrid scheme with either retransmission strategies helps maintaining a high throughput efficiency at the range of bit error rates, which significantly benefits multimedia applications.