Stability regions of two-way relaying with network coding

We consider a pair of nodes with stochastic traffic flows who wish to communicate in a bi-directional communication scenario using intermediate relays in two-hop fashion. Intermediate relays are capable of XOR network coding. Transmission scheduling is done by tailoring the backpressure algorithm to the problem at hand. Two main alternatives for network operation are either to have queues at the relays (hop-by-hop scheduling) or no queues at the relays (immediate forwarding). In this two-way network with stochastic flows, we formulate and show that the resulting stability regions of these two approaches are identical.