Energy and Channel Aware Geographic Forwarding Algorithms for Wireless Sensor Networks

In this paper we investigate energy efficiency and performance of a multi-hop communication in a wireless sensor network where energy efficient geographic forwarding algorithms are implemented. Starting from a reference case, based on geographic information only, which optimizes the advancement toward the destination, we introduce here adaptive strategies that exploit channel and energy information and try to optimize the energy consumption or the energy-to-advancement ratio. We also propose an integrated MAC algorithm, which uses forwarding metrics to control the contention of the channel, and explore the possible benefits that can be gained by the use of coding which reduces the power requirements in the transmission of the data packets. The results show that the use of channel and energy information in the forwarding process improves the energy efficiency, but the gain achievable is heavily influenced by the fixed energy cost of MAC operations. However, the proposed MAC design keeps the energy cost limited and independent of the node density. It is also shown, that the use of coding does not reduce energy consumption when the required processing is energy consuming. The best energy behavior is achieved by the forwarding algorithm that minimizes the energy-to-advancement ratio which saves 20-40% of energy with respect to the reference case