RNIndoor: A relay node deployment method for disconnected wireless sensor networks in indoor environments

In a 2D indoor environment, finding the proper location of relay nodes for wireless sensor networks is a difficult and time consuming job because walls, rooms and restricted areas can prevent the placement of nodes. Moreover, the number of relay nodes is an important factor. Too many relay nodes may increase installation cost and communication delays as well as spoil the beauty of the insides of buildings. In this paper, we present a heuristic relay node deployment method for indoor wireless sensor networks (RNIndoor). The method places as few additional relay nodes as possible to provide at least one path among the deployed nodes in a floor using structural information of the floor (indoor environment) and path loss generated from propagation models. The walls and restricted areas are considered in finding the locations of additional relay nodes. Our method can be effectively used in the initial stage of real deployment or a simulator in a wireless sensor network domain to reduce installation time and cost. We compared it with other deployment methods to validate the superiority of our method.