Wireless Sensor and Actuator Networks: Algorithms and Protocols for Scalable Coordination and Data Communication

10.2 MOVEMENT-ASSISTED SENSOR PLACEMENT

Four subproblems of movement-assisted sensor placement have been investigated for coverage improvement in the literature. This section gives these problems a general definition. A comprehensive survey of existing solutions can be found, respectively, in the following sections.

10.2.1 Sensor Placement by Actuators

Actuators may serve as network installers for sensor deployment. They carry sensors as payload and move around in the ROI. While traveling, they deploy sensors at desired positions (e.g., vertices of certain geographic graph) to “install” a connected sensor network with desired coverage.

If ROI is bounded, and there are sufficient sensors, the key problem is how to guide actuators to explore entire ROI. Otherwise, the challenge will be how to ensure a coverage of good compactness. Compactness can be measured by the radius of the maximum hole-free disk in the final network. It reflects the omni-sensibility of the network.

10.2.2 Coverage Maintenance by Actuators

After initial sensor deployment, actuators can be used as network maintainer to improve existing coverage by planting sensors at designated location. Specifically, upon request, they will move to reported sensing holes (e.g., due to improper initial node distribution or runtime node failure) and drop new sensors there to fill the holes with minimum delay. If actuators have no sensors in hand, then they have to first fetch spare sensors in the network. The delay from the moment ...