Retransmission or redundancy:Transmission reliability study in wireless sensor networks

As an application-driven network,wireless sensor network generally requires data reliability to maintain detection and response capabilities.Although two approaches,namely,retransmission and redundancy,have been proposed to enhance data reliability,the theoretical work is required to evaluate their impact on transmission reliability and energy efficiency.In this paper,we offer a comprehensive theoretical study on packet arrival probability and average energy consumption for both approaches.Our analysis and simulations indicate that when loss probabilities remain low or moderate,erasure coding,a typical redundancy-based scheme,is more energy efficient than retransmission.We also demonstrate that the resistance capability of erasure coding against packet loss weakens as the hop number increases,which motivates us to propose two improved mechanism based on the idea of the loss detection and the loss recovery.Finally,the simulation results carried out using TOSSIM verify the performance of different mechanisms both in the chain topology and the tree topology.