Opportunistic transmission for wireless sensor networks under delay constraints

We propose an opportunistic transmission strategy for wireless sensor networks (WSNs) that operate in a strict energy-constrained environment. The WSNs of interest in this work are assumed to host delay-sensitive applications. Our proposed transmission strategy named binary-decision based transmission (BDT) attempts to transmit at good channel conditions while meeting the delay constraint, under time-varying wireless channel. The Markov decision process (MDP) is used to find optimum threshold for transmission decision. Our BDT scheme initiates transmission only when the channel quality exceeds the optimum threshold, so that unsuccessful transmissions causing a waste of energy are avoided whenever possible. Extensive simulations are performed to verify the performance of our proposal over wireless fading channels. The simulation results show that the BDT scheme has 35% higher energy efficiency than its counterparts; thereby further prolonging the network lifetime.