Relay Node Placement in Wireless Sensor Networks with Bounded Transmission Range

Wireless sensor networks (WSNs) have been applied to many applications since emerging. The design of a WSN should focus on their performance and lifetime due to the high operational costs caused by the lack of infrastructure and its typical use. In this paper the reduction of the operating cost of WSNs is proposed by limiting the transmission range of the radio transceivers of the network nodes and the insertion of relay nodes. The problem to be solved consists in, given an upper limit of transmission range and the sensor nodes positioned in the plane, computing the minimum number of relays, its position and transmission range and the transmission range of the sensor nodes such that the resulting network is connected and no node exceeds the transmission range limit. Since this problem is NP-complete, this work presents the implementation of a constructive heuristic, a local search algorithm and a GRASP metaheuristic to solve it, showing the effectiveness of the algorithms through computational experiments.