2-Connected relay placement problem in wireless sensor networks

This paper addresses a more reliable and fault-tolerant version of the standard relay placement problem (RPP) in the design and deployment of wireless sensor networks. Given a set of sensors in a Euclidean plane, the 2-connected relay placement problem (2CRPP) is to place minimum number of relays such that each sensor can communicate with at least one relay, and all relays jointly form a 2-connected network. Since 2CRPP is proven to be NP-hard, in this paper we proposed a polynomial time approximation algorithm for the problem and mathematically proved that its approximation ratio is bound by (4+ε), in the worst case.