A Comparison of Packet-Level and Byte-Level Reliable FEC Multicast Protocols for WLANs

For wireless multicast applications like multimedia conferencing, voice over IP and video/audio streaming which require reliable transmission of packets within short delivery delay, adding forward error correction (FEC) can enhance packet error rate (PER) performance under low channel conditions, but cannot guarantee a reliable transmission. However, for applications like file transfer, distributed computing, chat and whiteboard sharing, reliability is crucial to the performance of the application. Reliable FEC or hybrid automatic repeat request (H-ARQ) can provide reliability, and can be deployed at different levels of the protocol stack. In this paper, we compare the performance of a reliable packet-level FEC protocol and a reliable byte-level FEC protocol through simulation and analytical analysis. Our result show that byte-level FEC can deliver a higher reliability performance in terms of throughput and delivery ratios.