Throughput and Energy Efficiency in Topology-Controlled Multi-hop Wireless Sensor Networks

摘要

In the context of multi-hop wireless networks, various topology control algorithms have been proposed to adapt the transmission range of nodes based on local information while maintaining a connected topology. These algorithms are particularly suited for deployment in sensor networks which typically consist of energy constrained sensors. Sensor nodes should support power adaptation in order to use the benefits of topology control for energy conservation. In this paper, we design a framework for evaluating the performance of topology control algorithms using overall network throughput, and total energy consumption per packet delivered, as the metrics. Our goal is to identify the scenarios in which topology control improves the network performance. We supplement our analysis with ns2 simulations using the cone-based topology control algorithm. Based on our analysis and simulations, we .find that link layer retransmissions are essential with topology control to avoid throughput degradation due to increase in number of hops in lightly loaded networks. In heavily loaded networks, the throughput can be improved by a factor up to k~2, where k is the average factor of reduction in transmission range using topology control. Studies of energy consumption reveal that improvements of up to k~4 can be obtained using topology control. However, these improvements decrease as the traffic pattern shifts from local (few hop connections) to non-local (hop lengths of the order of the diameter of the network). These results can be used to guide the deployment of topology control algorithms in sensor networks.