Reliable wireless multicast using fast low-density codes

Recently, there has been the high demand for one-to-many reliable multicast distribution under wireless environments. The characteristics of multicast protocol combined with the inherent wireless channel impairment make the network performance drastically degrade as the group size or packet loss rate increases. Although the conventional Reed-Solomon FEC (forward error correction)-based scheme can mitigate problems such as NACK implosion and exposure, its computational complexity makes itself inappropriate for software implementation in resource-limited wireless device. We studied efficient wireless multicast protocol using low-density erasure codes known as tornado FEC and furthermore improved the encoding and decoding speed of tornado FEC by our novel interleaving technique without degrading its overall performance. We call new codes homogeneous tornado FEC (HTF). Our protocol scheme aims at a multicast bulk data distribution in wireless local area networks such as IEEE 802.11.