Approximation Algorithm for Avoiding Hotspot Formation of Sensor Networks for Temperature Sensitive Environments

Sensing and transmission phenomena of an implanted sensor dissipates energy which results in rise in temperature of its surroundings. Simultaneous operation of such multiple active sensors increases the temperature of the surrounding environment causing hotspots. Such hotspots are highly undesirable as they may cause damage to the environment as well as to the sensor network, posing a challenge for deployment of sensors. The problem is further enhanced for a temperature sensitive environment, as the allowable threshold temperature for such environments is less. Here we investigate the formation of hotspots in such temperature sensitive environments due to the heat dissipation of multiple active sensors and try to achieve a maximum coverage of such networks avoiding hotspots. We formulate this as a variation of the maximum independent set problem for hypergraphs. We devise an Integer Linear Program to achieve the optimal solution for the problem. We also provide a greedy heuristic solution for the problem. For a special case of this problem, where the hotspots are formed due to pairs of sensors only, we prove a 5-approximation bound for the greedy solution. Experimental results show that our algorithm achieves near-optimal solutions in almost all the test cases.