Scaling Laws for Delay Sensitive Traffic in Rayleigh Fading Networks

The throughput of delay sensitive traffic in a Rayleigh fading network is studied by adopting a scaling limit approach. The case of study is that of a pair of nodes establishing a data stream that has routing priority over all the remaining traffic in the network. For every delay constraint, upper and lower bounds on the achievable information rate between the two end-points of the stream are obtained as the network size grows. The analysis concerns decentralized schemes, in the sense that all nodes make next-hop decisions based only on local information, namely their channel strength to other nodes in the network and the position of the destination node. This is particularly important in a fading scenario, where the channel strength varies with time and hence pre-computing routes can be of little help. Natural applications are remote surveillance using sensor networks, and communication in emergency scenarios.