An channel-awared transmission protocol in wireless sensor networks

Abstract

In this paper, we investigate the problem of optimal stochastic delivery protocols in Wireless Sensor Networks (WSNs). To minimize the expected energy cost of the data delivery process over an error prone multi-hop wireless link, the sub-delivery process on each hop is formulated into a finite horizon average cost Markov Decision Process (MDP) with constrain of desired probability. It is assumed that the channel can be modeled as a Finite State Markov Chain (FSMC) model, and that retransmissions are allowed. We first seek the optimal solution on N horizon MDP of the problem, and then use a policy iterative algorithm to affirm the horizon number for each system state. Using the concept of convexity on the value function and supermodularity on the action state cost function, the optimal transmission policy is proved to be non-decreasing with the accumulative probability and non-increasing with the remaining horizon. The threshold policy based protocol is applicable for source constrained WSNs. The novelty of our work is that we improve the energy efficient of stochastic data delivery protocols in WSNs significantly, and give out logical proofs of the advantage of our algorithm. Finally, the numerical examples validate the theoretical results farther. © 2012 Springer-Verlag.