Packet-level FEC research over wireless networks

Over wireless networks, interference caused by external sources, multipath fading due to terrestrial obstruction, and transmitters or receivers' mobility will result in bursty errors of transmitted packets. To deal with the problem, in the paper an improved packet-level FEC scheme, the XOR-FEC, is proposed The scheme, under certain conditions, can recover packets of both corruption and erasure. Because its main operation only involves the use of exclusive-or(XQR), the scheme can be implemented simply with software and is low complexity To smooth the jitter among packets in receivers, a double-window scheme is presented Simulation experiment results show: the improved scheme decreases the number of redundant parity packets to be used, so that the amount of computing to encode and decode can be saved And by adjusting sending windows, at almost same packet error rate, to use same number of redundant packets, improved scheme can recover more packets than a packet-level FEC scheme based on Reed-Solomon code.And experiments show that under certain condition the XOR-FEC scheme can decrease the PER without increasing redundant rate.