A multiple sink repositioning technique to improve the energy efficiency of wireless sensor networks

An integral aspect for designing any efficient wireless sensor network is the conservation of energy and the optimization of the power consumption. Continuous and prolonged availability of power plays a vital role in keeping the sensors energized. The power required by the sensors is largely dependent on their batteries which may require regular recharging and periodic replacement. But practically it may not be viable to recharge or replace the batteries. Hence there is a need to design an energy efficient protocols which would result in significant amount of energy saving and help in elongating the lifetime of the network. In this paper we have proposed a sink positioning technique in which multiple mobile sinks are deployed across the entire wireless sensor network. Moreover in this technique there is no constraint on the location of the sinks. The sinks can be placed anywhere within the geographic area of the network. The main aim is to minimize the energy consumption and for this purpose we have divided the network lifetime into different circles and the optimal position of the various sinks is calculated at the beginning of each circle after which the sinks are moved to the new location. This movement of the sinks to a new optimal location results in significant amount of energy saving and also avoids the energy hole problem. The proposed sink positioning algorithm has been simulated in the NS-2.32 environment. The three performance metrics considered in order to evaluate the performance of the proposed technique are the packet delivery ratio, average energy consumption and the average number of packets dropped. The X graph for the packet delivery ratio, average energy consumption and the average number of packets dropped were plotted for static sink, multiple sink and multiple mobile sink approach and it was observed that multiple mobile sink positioning technique achieves significant amount of energy saving and also helps in the extension of the lifetime of the wireless sensor network in comparison to the static as well as multiple sink approach.