Broadcast file distribution in a four-node packet radio network with network coding and code-modulation adaptation

We employ a four-node network to obtain preliminary comparisons between two forms of network coding when they are used for broadcast distribution of files in tactical packet radio networks. Each of the four nodes in the network has a half-duplex packet radio, and the nodes are connected by radio links that have time-varying fading. We present two methods for network-coded broadcast distribution. One method uses fountain coding and the other employs random linear network coding. Packet-by-packet adaptations of modulation and channel coding are employed to mitigate the effects of fading on the links. Our network-coded distribution methods are able to exploit the broadcast nature of the wireless medium for improved throughput, and they require only a single frequency band that is used for all packet transmissions in the network.