Section: New Results

WSN Redeployment

Participants : Pascale Minet, Saoucene Mahfoudh Ridene, Ines Khoufi.

This is a joint work with Telecom SudParis: Anis Laouiti.

Centralized redeployment algorithm based on Virtual Forces

In many applications (e.g military, environment monitoring), wireless sensors are randomly deployed in a given area. Unfortunately, this deployment is not efficient enough to ensure full area coverage and total network connectivity. Hence, all the considered area must be covered by sensors ensuring that any event is detected in the sensing range of at least one sensor. In addition, the sensor network must be connected in terms of radio communication in order to forward the detected event to the sink(s). Thus, a redeployment algorithm has to be applied in order to achieve these two goals. In this context, we have proposed redeployment algorithms based on virtual forces. First, we have designed and simulated a centralized algorithm called CVFA. This algorithm is executed by a specific node which has global information of node positions.

Distributed redeployment algorithm based on Virtual Forces

Then, we proposed DVFA, Distributed Virtual forces Algorithm. Each node in the network executes DVFA and computes its new position based on information collected from its neighbors.

Performance evaluation shows that both CVFA and DVFA give very good coverage rate (between 98% and 100%) and ensure the connectivity between sensors.

Distributed redeployment algorithm based on Virtual Forces in the presence of obstacles

Moreover, in a real environment, obstacles such as trees, walls and buildings may exist and they may impact the deployment of wireless sensors. Obstacles can prohibit the network connectivity between nodes and create some uncovered holes or some accumulation of sensors in the same region. Consequently, an efficient wireless sensors deployment algorithm is required to ensure both coverage and network connectivity in the presence of obstacles. We have focused on this problem and enhanced our Distributed Virtual Force Algorithm (DVFA) to cope with obstacles. Simulation results show that DVFA gives very good performances even in the presence of obstacles.