Queueing models for the performance of multihop routing in a intermittently-connected mobile network

Consider an intermittently-connected mobile ad-hoc network with a single source/destination aided by n mobile relay nodes each of which has a finite storage buffer. In this paper we develop, for the first time, an analysis of the steady-state performance of multihop routing in such a network with a general mobility model and characterize it in terms of throughput and transmission-cost overhead. We investigate whether multihop routing has any potential for improvement over two hop routing. We show that analytical models for performance under multihop can be obtained by employing queuing-theoretic techniques and embedded-Markov-chain identification. The solution offered is in the form of non-linear steady-state equations which can be efficiently solved iteratively. The key outcome of this work is that multihop can indeed improve upon two-hop routing in the finite-buffer regime, by means of mitigating the reduction in throughput caused by limited storage (leading to blocking/saturation of buffers). However, the improvement in throughput diminishes as the buffer size grows, and comes at the cost of additional relay-to-relay transmissions.