Coverage problems in energy harvesting wireless sensor networks

A Wireless Sensor Network (WSN), in general, contains many low-cost sensor nodes, each with the capability to monitor its surrounding environment. As conventional or non-rechargeable WSNs are restricted by the finite battery capacity of sensor nodes, researchers have sought the help of renewable energy techniques such as solar and wind. Consequently, each sensor node, in the resulting energy harvesting WSN, is able to harvest energy and recharge its battery from its environment. Assuming no other failures, WSNs are now able to operate perpectually if all nodes have energy neutral operation; i.e., they harvest more energy than what they spend. A fundamental problem in energy harvesting WSNs is to maximize coverage, whereby the goal is to capture events of interest that occur in one or more target areas. In this respect, duty cycling for complete targets coverage is important. Its objective is to ensure all targets are monitored continuously by at least one sensor node, whilst other sensor nodes can be in a low power sleep state to conserve energy and to recharge their battery. To date, existing works only study the duty cycling for complete targets coverage problem in non-rechargeable WSNs where the sensor nodes have no ability to refresh their battery. Moreover, past works on energy harvesting WSNs focus on maximizing event detection probability and do not require all targets to be monitored at all times. To this end, this thesis first addresses the duty cycling for complete targets cov-