Reliable and energy efficient wireless sensor network design via conditional multi-copying for multiple central nodes

Design of reliable wireless sensor networks considering energy efficiency is of utmost importance given their specific application domains and technical properties. As a contribution to the vast literature on resilient and fault tolerant network design, this paper offers a novel energy efficient conditional multi-copy and multi-path routing strategy. The motivation is to use limited energy of sensors as efficiently as possible and to improve network reliability and security via restricted redundant data generation. Namely, rather than all only the data passing through some central nodes are duplicated as a precaution against their malfunctioning. A limited number of nodes with higher data transmission allowance are determined as central at the design stage considering lifetime maximization objective. Consequently, 0-1 mixed integer programming models of two variants of the proposed strategy are presented in order to determine optimal routing. Moreover, several valid inequalities so as to improve solution times with commercial solvers and an efficient heuristic method for finding good solutions for large instances in reasonable times are proposed. Extensive test results show that simple restricted multi-copy strategies where every sensor duplicates its data are improved since the proposed strategies provide comparable levels of network reliability and yet extend network lifetime significantly.