Review on various routing protocols for heterogeneous wireless sensor network

In the last decade, tremendous growth had been observed in the use of wireless sensor networks (WSNs). Precisely WSNs are well-known in real time applications using homogeneous sensor nodes. As sensor nodes are battery powered, it will become dead after consumption of the battery which decides the lifetime of WSNs. The battery of sensor nodes is neither replaced nor recharged. Hence it is essential to introduce the techniques to prolong the lifetime of the WSNs. Heterogeneous nodes in wireless sensor network is an effective way to increase network lifetime. This involves the need for energy efficiency in heterogeneous WSNs. Limitation on energy is a major concern, and hence it can be managed efficiently using clustering. In homogeneous clustering, each sensor node has equal initial energy but in heterogeneous clustering. There are two or more types of sensor nodes that have different initial energy. This paper describes the various heterogeneous WSN protocols that carry out a survey of the recent clustering protocols for heterogeneous WSNs. Heterogeneous routing protocols for WSNs are categorized based on some predefined performance estimation metrics such as network lifetime, number of heterogeneity level, cluster head selection, energy efficiency and stability.