Energy-Efficient Routing in Frequency-Hop Networks with Adaptive Transmission

We describe and evaluate an energy-efficient protocol for routing traffic in frequency-hop (FH) store-and-forward packet radio networks that employ an adaptive transmission protocol. The adaptive transmission protocol allows the radios to adjust the power in the transmitted signal and the rate of a Reed-Solomon code to respond to variations in partial-band interference and propagation loss. Routing is accomplished using least-resistance routing (LRR) with a new metric that provides a quantitative assessment of the ability of a radio to receive and forward packets and includes a measure of the energy that is expected to be required for successful transmission. The new energy metric and LRR are integrated with the adaptive transmission protocol, and the performance of the new protocol suite is evaluated for a distributed FH network. The performance results presented in this paper are obtained from a simulation of wireless FH radio networks in which the characteristics of the links vary with time. Our results demonstrate that in FH networks that employ an adaptive transmission protocol, the new method for routing can adapt quickly to changes in interference conditions. We find that LRR with the energy metric works with the adaptive transmission protocol to improve the information throughput and energy efficiency of the network.