In wireless sensor networks (WSNs), coverage of the monitoring area represents the quality of service (QoS) related to the surveillance. In literature, a number of studies developed robot deployment and patrol algorithms. However, the efficiency of existing repair algorithms can be further improved in terms of time and energy consumption. Moreover, existing repair algorithms did not consider the existence of obstacles and the constraint of limited energy of the robot. This paper presents novel tracking mechanism and robot repairing algorithm for maintaining the coverage quality for a given WSN. Without the support of location information, the tracking mechanism leaves the robot's foot marks such that sensors that are nearby the failure region can learn better routes for sending repairing requests to the robot. Upon receiving several repairing request messages, the robot applies the proposed repairing algorithm to establish an optimal route that passes through all failure regions with minimal overhead in terms of the required time and power consumption. In addition, the proposed repairing algorithm also considers the remaining energy of the robot so that the robot can be back to home for recharging energy and overcome the unpredicted obstacles. Performance study reveals that the developed protocol can efficiently maintain the coverage quality while the required time and energy consumption are significantly reduced.
Wireless Communications and Mobile Computing Conference, 2008. IWCMC '08. International, pp.761-766