Energy-Efficient Circular Sector Sensing Coverage Model for Wireless Sensor Networks

Reducing the energy consumption in Wireless Sensor Networks (WSN) is an important goal, sought to extend the life-expectancy of the networks. One of the main problems in actual implementation is their inherently limited life-span, due to the (usually) not field-replaceable energy source. The energy consumption is due to the data and management communication, messages, sensing, processing (and storage) activities of the motes. The sensing may be local, e.g. temperature, radiation, humidity or similar physical measurement. There are a lot of applications, civilian or military alike, which implement some remote discovery, localization or tracking activities. In this case, the active sensing is performed mainly by emitting light, electromagnetic or sound waves. Obviously this imposes a heavy burden on the limited energy resources available to the mote, shortening his life and consequently the life of the WSN itself. Previously published sensing models use a circular coverage area around the motes, with fixed (unit-disk) or variable radius. Our work proposes a more energy-efficient sensing model, based on circular sectors with variable angles and radii, negotiated between the motes, as a function of their current energy capabilities. The performance of this model was checked vs. previously published schemes, using a proprietary simulation program, developed specifically for this purpose. The paper presents the results of simulations, showing significant energy savings. The obtained data confirm the viability and the advantages of this new sensing model. The possible implementation of such a WSN will significantly improve the energy-related performance of the WSN, allowing the development of new applications and improving the performance of existing ones.