Abstract: Because of the specific property of half-duplex over the IrDA links, Go-Back-N Automatic Repeat request protocol(GBN-ARQ) is different from GBN-ARQ over duplex links. In this paper, the GBN-ARQ protocol over half-duplex links was proposed, and the factors which affect the transmission system were expressed with proper parameters according the property of half-duplex links. I}hen, the general expression of average packet delay was obtained through analyzing the component of average packet delay by using queuing theory, which contains average packet waiting delay and packet service delay. At last, the influence of packet error rate, windows length and data packet length on system delay was analyzed by numerical simulation.

Key words: IrDA，Half-duplex,Go-Back-N ARQ, M/G/1 queuing systems