Average control information exchange between sensor nodes and

Average energyconsumption is defined as the total amount of energy (computation and communicationpower) consumed by all the participant sensor nodes during the simulation timeuntil the WHD algorithm calculates the total hole area that are found in ROI. Figure7 shows the simulation results of the average energy consumption by using all theparticipant nodes out of the total deployed sensor nodes to calculate the holesarea in the ROI with random number of holes and fixed number of sensor nodes.

 As known the energyconsumption is directly proportional to the network density (number of deployedsensors) in the ROI, so as the number of deployed sensor nodes increases theaverage energy consumption increases and vice versa. Since the energyconsumption is mainly caused by communication, WHD uses only a defined numberof sensor nodes, this leads to the minimal communication cost for neighborhooddiscovery and control information exchange between sensor nodes and the basestation node. Also the amount of aggregated data by the HNs are the minimal dueto the minimal use of sensor nodes in each cell, so the average energyconsumption decreases accordingly.

 It is clear fromFigure 7 that WHD algorithm outperforms PD algorithm in terms of average energyconsumption by approximately 44% average along the selected numberof sensor nodes, andoutperforms VCDHA by approximately 21% average along theselected number of sensor nodes. The enhancement of average energy consumption is mainlydue to the participation of less nodes to detect and calculate the holes area,and reduction of the communication between sensor nodes and base station. Whilethe WHD algorithm saves more power to calculate the holes area compared toother protocols, so WHD enhances the network life time and reduces the communicationoverhead, this is done mainly due to the reduction of communication between thenodes.