Improving probabilistic coverage and connectivity in wireless sensor networks: Cooperation and mobility

We study probabilistic coverage and connectivity in wireless sensor networks. Since many sensors are powered by battery, the sensing range and the communication range of static sensor nodes are very limited. As a result, it is very likely that the field is not completely covered and the network is not fully connected. However, we observe that clumps of sensors could be formulated and cooperation among the sensor nodes could be carried out, after the sensor nodes are randomly deployed in the field. With cooperation, the area covered by the sensor nodes increases and the data could be shared among the sensors within one clump. Moreover, mobile nodes (Mules) could be deployed in the field to further improve the coverage and connectivity. In this paper, we characterize the expected proportion of covered region, the time needed to obtain full connectivity, and the number of nodes connected by the Mules at certain time threshold. Our results show that significant improvement of coverage and connectivity can be achieved from cooperation and mobility.