Data Aggregation in Wireless Sensor Networks

With advance in technology, sensor networks composed of small and cost effective sensing devices equipped with wireless radio transceiver for environment monitoring have become feasible. The key advantage of using these small devices to monitor the environment is that it does not require infrastructure such as electric mains for power supply and wired lines for Internet connections to collect data, nor need human interaction while deploying. These sensor nodes can monitor the environment by collecting information from their surroundings, and work cooperatively to send the data to a base station, or sink, for analysis.

However, currently there are two limitations on these sensor nodes. First, the power supply is limited. Without electric infrastructure, the nodes are powered by batteries. Once the batteries run out of energy, the nodes die. Battery replacement is not economic, and sometimes infeasible. The sensor nodes will be very cheap once they are mass production products. Deploying new sensor nodes will be more economic than human power. Sometimes the sensor network may be deployed in a hostile or unreachable environment, such as a battle field or chemical waste disposal, and therefore it is not possible for a human to replace a depleted battery.