Mobility control for throughput maximization in ad hoc networks

Physical topology of an ad hoc wireless network imposes fundamental limits on its throughput capacity. In this work, we present a network design algorithm for configuring node locations in an 802.11 ad hoc network with the goal of improving the throughput capacity of the network. Given a network configuration (i.e., a mapping of network nodes to physical locations), we establish an inverse proportional relationship between the interference degree of the network and the guaranteed link-throughput. Motivated by this observation, we present an algorithm which progressively guides the network towards better configurations with lower interference degrees, which in turn increases the network's throughput capacity. Packet level simulations using the ns-2 simulator shows that the reconfigured topologies obtained by our algorithm consistently outperform the original network topologies for throughput and delay-related metrics. In particular, for many cases, we observed over 100% increase in the total network throughput and the minimum guaranteed throughput, over 60% increase in throughput fairness and over 50% reduction in the mean-service delay of packets. Our algorithm admits a simple distributed implementation and can be viewed as a distributed mobility control primitive for improving the throughput performance of mobile ad hoc networks. Alternately, our techniques can also be employed by a centralized designer during network creation time to obtain a network configuration with a high throughput capacity. To the best of our knowledge, ours is the first work which explores the use of guided network configuration strategies for improving the throughput capacity in ad hoc wireless networks. Copyright (C) 2006 John Wiley & Sons, Ltd.