Date Added: Dec 2012
The Wireless Sensor Network(WSN) has become an interesting field of research for gathering data in various situations. It has great potential value in many application areas such as in the military & national defense, environmental monitoring, remote monitoring dangerous areas & soon. Based on network structure, routing protocols in WSNs can be divided into two categories: flat routing, location based routing and hierarchical or clustering routing. Owing to a variety of advantages, clustering is becoming an active branch of routing technology in WSNs. The sensor nodes can be homogeneous or heterogeneous. Research on wireless sensor networks has often assumed homogeneous nodes. In reality, homogeneous nodes hardly exist. This leads to the research on heterogeneous network.