A Burst-Trapping Code for Feedback Communication Systems

Abstract

Many data communication channels are perturbed by "bursts" of noise separated by long intervals of comparatively low noise level. The block code described in this paper, a modification of the forward-acting scheme of S. Y. Tong, retransmits information which has been damaged by a noise burst in place of the parity-check digits of future blocks. The responsibility for error detection and correction is divided between the receiver and (via the feedback channel) the transmitter in such a way as to maximize the defense against both noise bursts and the occasional random errors between bursts. There is a fixed delay for decoding, in contrast to the variable buffering delay of ordinary retransmission-request systems. As a result, storage requirements are minimized and there is a constant throughput rate. The feedback channel can incorporate as much delay and be as noisy as the forward channel without significantly impairing performance. Simulation results are provided to illustrate the performance.