On control of inter-session network coding in delay-tolerant mobile social networks

Abstract

Delay (or disruption) Tolerant Networks (DTNs) are networks made of wireless nodes with intermittent connections. In such networks, various opportunistic routing algorithms have been devised so as to cope with the lack of contemporaneous end-to-end route between a source and a destination. We consider DTNs made of mobile nodes clustered into social communities, with unicast sessions. Network coding is a generalization of routing that has been shown to bring a number of advantages in various communication settings. In particular, inter-session network coding (IS-NC) is known as a difficult optimization problem in general. In this article, we introduce a parameterized pairwise IS-NC control policy for heterogeneous DTNs, that encompasses both routing and coding controls with an energy constraint. We derive its performance modeling thanks to a mean-field approximation leading to a fluid model of the dissemination process, and validate the model with numerical experiments. We discuss the optimization problem of IS-NC control in social DTNs. By showing numerical gains, we illustrate the relevance of our approach that consists in designing IS-NC control policies not reasoning on specific nodes but instead on the coarse-grained underlying community structure of the social network.