On the interaction between network coding and the physical layer – information theoretic results and a case study

The question of how and whether to join physical layer and network coding remains actively investigated. In this talk, we present some recent information-theoretic results and an application illustrating a view of this question. We begin by considering whether there are benefits, in capacity, from integrating network and physical layer coding. Network equivalence implies it is interference and broadcast effects, rather than the presence of noise, that might lead to such capacity benefits. However, in regimes of low SNR and of high SNR, where broadcast and interference, respectively, may be the dominant effects, integration appears to provide negligible benefits. We conclude with results from the first network coding chip. The benefit of both network and physical coding can be seen to be cumulative, even in the absence of coordination between the two.