Approximate Analysis of a Round Robin Scheduling Scheme for Network Coding

Abstract

Network coding (NC) has been proposed as a way to compress flows of packets by combining different packets, provided that there is sufficient redundancy through multiple transmission paths so that the receiving nodes can then decode the flows to reconstruct all of the individual packets. However NC does introduce additional computational overhead, and also creates different additional delays which are the subject of this paper. In particular, we evaluate the queueing and delay performance of NC at intermediate nodes of a store and forward packet network when the cross-encoding of packets is restricted within disjoint subsets of the traffic streams so that packets from different subsets cannot be encoded together. We propose a round robin scheduling scheme for serving these disjoint subsets, and present a queueing model for a single encoding node that captures the effect of NC. The model is analyzed approximately using a decoupling approach, and can be used to predict the additional delays incurred by packets in nodes that use NC. The accuracy of the analytical solution is validated via simulations.

Research supported by the EU FP6 CASCADAS and FP7 DIESIS Projects of the EU Future and Emerging Technologies Program.