Johannes Hund

Applied Network Coding in Wireless Networks Johannes Hund German edition

Network coding describes the technique to perform coding operations on contents throughout the network, increasing the information density of a single transmission and therefore increasing network throughput. The idea of network coding was first introduced by Ahlswede et al. [AHL00]. Later it was shown by Li et al. [LI03] that simple, linear codes where sufficient for network coding in multicast networks, and then Koetter and Médard [KOE03] showed the same for arbitrary networks. Instead of transmitting one packet after the other, like traffic on roads, network coding exploits the fact that instead of simply forwarding the transmitted data can be used for calculations that improve the information density per packet. Therefore data for multiple packets for different destinations can be combined (encoded) and sent in one broadcast to all destinations. The premise is that each destination receives enough data to reconstruct the original information. Thus each relaying node (routers or mesh nodes) can combine several input packets in one or more output packets that will be sent "downstream". A receiver only has to receive enough linear combinations of the packets it is looking for in order to reconstruct the data.