Energy efficient data gathering scheme for wireless sensor networks with static and mobile sinks

Mobile sink has been widely used in wireless sensor networks to balance energy consumption among sensor nodes and to prolong the network lifetime. But, as mobile sink moves, sensor nodes have to change their routes to mobile sink frequently, which results in a lot of energy consumption and also a very large transmission delay accordingly. Although using a static sink may lead to shorter network lifetime, it can get a relatively small transmission delay and need not to change their routes constantly. In order to prolong the network lifetime and to reduce the transmission delay, we propose an energy efficient data gathering scheme with both a static and a mobile sink to work together. Mathematical analysis and simulation results show that we can greatly improve the network lifetime and reduce the transmission delay at the same time by using our scheme.