Loss network models and multiple metric performance sensitivity analysis for mobile wireless multi-hop networks

Abstract

We develop and evaluate a new method for estimating and optimizing various performance metrics of mobile wireless multi-hop networks, including MANETs. The method utilizes approximate (throughput) loss model that couples the physical, MAC and routing layers effects. The model provides quantitative statistical relations between the loss parameters that are used to characterize multiuser interference and physical path conditions on the one hand and the traffic rates between origin destination pairs on the other. The model considers effects of the hidden nodes, node scheduling algorithms, MAC and PHY layer failures and unsuccessful packet transmission attempts at the MAC layer in arbitrary time varying network topologies where multiple paths share nodes. The method then applies Automatic Differentiation (AD) to these implicit performance models, to compute sensitivities of various performance metrics with respect to network parameters. We demonstrate the method by applying it to time varying mobile network topologies, including reduced connectivity instances, with both random access MAC (contention mode of the 802.11) as well as reservation based MAC (USAP TDMA based protocol). We analyze throughput, delay and packet loss as metrics and investigate metric optimization and tradeoff analysis. Finally we provide numerical results for realistic mobile networks with time varying topologies.