A SELECTIVE ARQ PROTOCOL WITH A FINITE-LENGTH BUFFER

Automatic repeat request (ARQ) techniques with error-detecting codes a re commonly used in communication systems. Of these, selective protoco ls, while the most efficient, have the notable drawback of requiring l arge buffers at the receiver side. A new selective ARQ protocol with a finite-length buffer is described in this paper. If N is the number o f codewords transmittable in the round-trip delay, the described proto col requires a buffer having length equal to N + N(a), + N(a) greater- than-or-equal-to 2 being an integer. A lower bound on the throughput o f the described ARQ protocol is derived. The proposed protocol achieve s higher throughputs than similar schemes, giving comparable results t o selective protocols with infinite-length buffers for high error rate s in the communication channel.