Scattered Random Network Coding for Efficient Transmission in Multihop Wireless Networks

Packet error rate dramatically increases when transmissions go over multiple hops in wireless networks, leading to substantial throughput performance degradation. However, in real wireless channels, bit error probabilities vary across different bit positions in one modulation symbol, and corruption of the packet is largely due to the incurred errors on those “bad” bit positions. To improve the throughput performance in multihop wireless networks, in this paper, we propose a novel scattered random network coding (which is referred to as S-RNC) scheme, which further exploits the usefulness of random network coding and takes advantage of error position diversity. In S-RNC, the random-network-coded blocks are classified into different groups, and certain groups of blocks are selected as protected blocks. The sender and relays always scatter the bits of these protected coded blocks on “good” bit positions (with low error probability) and the rest on “bad” bit positions (with high error probability). Rather than sharing the same error rate across all blocks in the conventional transmission scheme, the error probabilities of protected blocks in S-RNC significantly decrease, even over multiple hops, which is helpful in achieving overall higher throughput, particularly under poor channel conditions. Corroborating our intuition, our extensive simulation results show that S-RNC substantially improves throughput performance in multihop mode of wireless networks.