International Journal of Modern Engineering Research (IJMER)
A wireless sensor network is an infrastructure comprised of sensing (measuring), computing and communication elements that gives an administrator the ability to instrument, observe and react to events and phenomena in a specified environment. The administrator typically is a civil, governmental, commercial, or industrial entity. The environment can be the physical world, a biological system or an Information Technology (IT) framework. Routing is very difficult in wireless sensor network due to a large number of sensor nodes. In wireless sensor network, routing can be divided into flat routing, hierarchical routing and location-aware routing. Hierarchical routing can be further divided into two parts: dynamic and static hierarchical routing or clustering-based routing.