Partial sensing coverage and deployment efficiency in wireless directional sensor networks

Unlike most existing works that focus on a conventional omni-directional sensor network, we investigate the sensing coverage problem in a directional sensor network through mathematically modeling, analysis, and computer-based simulation evaluation. Research results show: 1) A factor of (2π/θ) more sensors will be required to provide the same sensing coverage in a θ(θ <; 2π)-directional sensor network with respect to its counterpart omni-directional sensor network; 2) Employing application-tolerable partial sensing coverage is of significant importance for directional sensor network implementation in practice, as a noticeable fraction of sensors can be saved; For example, 50% and 66.67% sensors can be saved for 90% sensing coverage as compared to 99% and 99.9% sensing coverage respectively under the same network settings; 3) The node saving rate of employing partial sensing coverage α(α <; 1) with respect to full sensing coverage f(f ≈1), derived as ηα = ln(1-α)-ln(1-f)/ln(1-f), is solely determined by the sensing coverage requirement in an application and is independent of sensor features. Simulation results validate the modeling, derivation, and analysis.