FEC和ARQ技术在可靠点—多点传输中的传输代价分析和比较

Transmission Cost Analysis and Comparison of FEC and ARQ Techniques in Reliable Multicast Transmission

由于自动重复请求(ARQ)用于点—多点传输面临可伸缩性差的问题,因而前向纠错(FEC)技术近来得到重视。本文推导了在给定多点转发树拓扑结构和链路丢失率条件下计算端一端FEC机制传输代价的方法,进行了分析和模拟。研究表明:对可靠点—多点传输,FEC与重传相比会大大降低带宽需求,并且它们的性能差距随接收方数目的增加而扩大,即FEC具有更好的可伸缩性,适于大规模组通信应用。

Because Automatic Repeat reQuest(ARQ)techniques do not scale well to multicast pro tocols with large number of receivers,Forward Error Correction(FEC)techniques were payed at tention to recently. However, there was little study on the performance analysis and comparison of these two techniques in reliable multicast transmission. This paper gives a analysis method to com pute the transmission cost of the two techniques, given arbitrary multicast tree topology and link loss probability. We studied the performance using analysis and simulations. This research shows that for reliable multicast, comparied with retransmission, FEC techniques greatly reduce band width requirements. Further more, the performance gap enlarges as the number of receivers in creases which means FEC techniques have better scalability and are suitable for large multicast group.