Analysis and design of efficient wireless networks.

Abstract

We present a generic integrated design methodology that is suitable for many kinds of mobile systems. The integrated design methodology takes into account the coupling among the subsystems and simultaneously optimizes their operation under an energy constraint. We show that significant improvement in performance can be achieved by using the integrated design methodology compared with traditional design methodologies. We evaluate the tradeoff between energy consumption and performance for several network scenarios. Routing is an efficient method for connectivity and low energy consumption of wireless networks. When each node is equipped with an omni-directional antenna, a point-to-multipoint connection is often available for routing. When the design goal is to minimize the maximum power consumed by the nodes in a network, we provide an algorithm with polynomial-time complexity that assigns power to each node for unicast, broadcast, and multicast sessions. When the design goal is to minimize the total power consumed by the nodes in a network, we provide an algorithm with polynomial-time complexity that assigns power to each node for a unicast session and show that the computational complexity of routing algorithms for broadcast and multicast sessions is NP-hard. We introduce transport efficiency to capture both bandwidth efficiency and energy efficiency of wireless networks. We show that for linear networks the optimal transport efficiency is inversely proportional to the end-to-end distance for one physical layer model and observe through numerical results that the same is true for many other physical layer models. We investigate the interference caused by space-time coding and an ordinary end-fire antenna array to neighboring networks. We show that the ordinary end-fire antenna array gives higher transport efficiency than space-time coding when the number of receiving antennae is small and space-time coding gives higher transport efficiency than the ordinary end-fire antenna array when the number of receiving antennae is large. We indicate that cooperative communication between linear networks can improve transport efficiency, but it gives marginal benefit if the cooperating networks are separated too far apart.