Energy Efficient Cooperation Based on Relay Switching ON–OFF Probability for WSNs

Abstract

Cooperative communications can substantially improve the performance in fading channels. However, in energy-constrained wireless sensor networks, the benefits of cooperation only go until certain limits, beyond which the energy cost of cooperation can be significant and unprofitable. We propose a cooperative scheme in which the relays activate the receiving circuitry based on a switching ON–OFF probability. We derive analytic expressions for the amount of effective information transmitted through the network and the associated outage probability under Nakagami- m fading channels. Based on the developed analysis, we formulate an optimization problem in which the switching ON–OFF probabilities are adjusted to reduce the energy consumption, subject to an outage probability constraint. We evaluate the performance of the proposed scheme under fixed and random network topologies. Our results indicate that the proposed scheme substantially outperforms the standard cooperative reception approach in terms of the amount of effective information transmitted through the network.