A NEW SELECTIVE ARQ SCHEME WITH A FINITE 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 of th e described ARQ protocol is derived. The proposed protocol achieves hi gher throughputs than similar schemes, giving comparable results to se lective protocols with infinite-length buffers for high error rates in the communication channel.