Delay and coding gain analysis of a truncated type-II hybrid ARQ protocol

Time delay of a truncated type-II hybrid ARQ protocol with one retransmission is analyzed by using queueing theory. The truncated protocol uses rate 1/2 error correcting codes. Parity bits for error correction are transmitted only when they are needed. It is shown that the truncated type-II hybrid protocol has a bounded delay and bounded queue length under typical communication traffic conditions. The error performance of the truncated protocol is further analyzed for a normalized Nakagami-m fading channel and compared with the performance of a conventional (untruncated) protocol. The results show that the truncated protocol provides coding gain improvement over the untruncated type-II hybrid ARQ protocol. Thus, it is suggested that the truncated protocol is best suited to power- and delay-limited mobile applications