J. Tovirac and W. Zhang (Australia)
wireless network standards and protocols, multicast, P Mul, hybrid FEC/ARQ
Simulation studies have been conducted to determine the benefits of forward error control (FEC) enhancement on automatic repeat request (ARQ) based reliable multi cast protocols, particularly in the wireless environment. As the first step, an ideal FEC code was added to a reliable multicast protocol P Mul as the base protocol. Originally, P Mul’s error control mechanism is based on ARQ where the multicast group members periodically respond with a list of missing packets. Also, in the cases when the loss is independent for different receivers, the entire message of ten needs to be retransmitted multiple times. With an ideal FEC scheme, improvement in the transmission efficiency has been observed. By ideal FEC, it was assumed that the FEC code provides unlimited number of parity packets, or an arbitrarily low rate erasure code. Every packet from the new round of retransmissions is a parity packet, and can be used to recover any previously lost packet. The simu lation study shows throughput improvements especially at the high bit error rates.
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