Pre-repeat selective-repeat ARQ in fading channel

A new selective-repeat (SR) ARQ scheme using the pre-repeat (PR) technique is proposed. The proposed scheme is efficient in digital cordless-phone systems employing TDMA-TDD under slow fading environments. Because fading affects both up-link channel and down-link channel simultaneously, the occurrence of error in the up-link channel is closely correlated with that in the down-link channel. This characteristic can be applied to predict errors in transmitted data by observing received signal. In this paper, throughput efficiency of the proposed scheme is investigated by computer simulation, and is compared with conventional SR-ARQ. It indicates that the proposed scheme is advantageous to transmission with a long round-trip delay.