An Analytical Study of Network Coding in the Presence of Real-Time Messages

With network coding, two data packets are transformed into one by a simple XOR-operation. The transformed packet is transmitted and each original packet can be retrieved at its destination node through a similar XOR-operation. Network coding is an important research topic as it radically challenges existing networking paradigms. In this paper we provide an analytical study of the impact network coding has on the delivery of real-time packets (i.e., packets with deadlines). We model a router as a queueing system where packets arrive from two independent Poisson flows. We obtain an exact expression for the goodput of the system and study the goodput gain that can be achieved by performing network coding. We verify the validity of the model through simulations.