Avoidance of Energy Holes in Wireless Sensor Networks: A Review

This survey is prepared to have an understanding about energy holesin wireless sensor networks, variousmechanisms to avoid them and a comparative study of these mechanisms. The sensing devices called nodes which are installed in the vicinity of base station (BS) requireto forward data from far-flung nodes (since distantnodes require more energy to transmit, hence they route their data through multiple hops until it reaches the base station) in addition toforwarding their own datawhichmakes the energy of these nodesdrain more rapidly than the rest of the nodes due to this extra work of relaying. Thus nodes near the sink die out faster leading to creation of energy holes. Due to the presence of energy holes data cannot be forwarded to BSsince the nodes near to BS which feed data to BS have died out, even though the rest of the nodes of the network are still alive having highremaining energy and are continuously sensing and transmitting. Thus the lifespan of the network isdecreased. So, energy hole is a major problem in WSNs which should be avoided. Although energy holes cannot be removed completely from WSNbut with the application of various energy saving schemes, they can be avoided and lifetime of the network can be prolonged.