Energy efficient forwarding strategies for wireless sensor networks in presence of fading and power control

In this paper we propose energy efficient forwarding techniques in a fading environment which exploit channel knowledge by means of nodes cooperation. Unlike forwarding strategies based on geographic information only, channel knowledge allows to take advantage from diversity by means of selection of the best node to forward the packet, and also to achieve higher energy savings thanks to power control. We also consider the case of multi-route diversity where redundancy packets are sent over different paths. We propose several adaptive strategies which explicitly address the energy issues and we compare them in terms of total consumed energy, mean packet error probability and delay. As a reference case we consider a forwarding strategy based on pure geographic routing (without channel knowledge). The results show that a considerable improvement can be obtained with respect to the pure geographic forwarding. Our algorithms are also in the direction of a cross layer view, since routing decisions are taken adaptively through physical layer information.