Optimal Node Placement in Wireless Underground Sensor Networks

Wireless Underground Sensor Networks (WUSNs) are active and emerging area of application of Wireless Sensor Networks (WSNs), whereby sensor nodes are located under the ground environment. The communication between the nodes is done underground, with the aim of sensing events to transmit the sensed events to the sink, which is normally in the terrestrial environment. The most challenging issue in the design of wireless sensor networks for the application of localization in the underground environment, mostly for miner’s location, is the sensor nodes’ placement problem. In this paper, we formulate a nonlinear program to determine the optimal information extraction in a grid based wireless underground sensor network. We then carefully study the cost of transmitting a bit of sensed information in the underground environment, were we then analyse the average transmission cost (energy consumed in joules per unit distance) for both variation in transmission distance between nodes, packet size (bits), and number of nodes in the network (network node density). The result shows that through optimal node placement approach, energy consumed in the network can be minimized if nodes are selectively placed using the minimum transmission cost. This work provides an insight on average transmission cost for deploying wireless underground sensor networks for the application of underground miners’ localization and protection.