The conventional go-back-

ARQ is inadequate for error control on satellite channels due to the large round-trip delay and high bit rate. The throughput efficiency of this system drops rapidly as the channel error rate increases. In this paper, a variation of the go-back-

ARQ is described. This variation reduces the effect of the round-trip delay, and hence increases the system throughput efficiency. Therefore, it may find applications m satellite communication systems or other systems where round-trip delay is large.