Improved Zonal Stable Election Protocol (IZ-SEP) for hierarchical clustering in heterogeneous wireless sensor networks

Wireless Sensor Networks (WSNs) refer to networks of thousands of sensor nodes deployed randomly to sense and monitor the state condition of the physical environment. The viability of WSN relies on the limited power of batteries that cannot be replaced or recharged in most cases. To increase the lifetime of WSNs, researchers regularly develop energy-efficient routing protocols that reduce the energy costs of sensor nodes. Many studies have shown that hierarchical routing protocols are very effective to extend network lifetime utilizing the threshold-based cluster head (CH) selection techniques. In this article, a heterogeneity aware routing protocol known as Improved Zonal Stable Election Protocol (IZ-SEP) is proposed for heterogeneous WSN, where sensor nodes communicate with the base station (BS) through a hybrid approach, i.e., a certain number of nodes communicate directly with the BS, while the rest rely on clustering mechanism. The proposed protocol is a two-level heterogeneity aware routing protocol where the network field is divided into two zones based on nodes’ initial energy. In this protocol, the CH is selected using the residual energy of each node and the number of neighbors of each node within the cluster range. The performance of IZ-SEP is evaluated and compared to the existing parent protocols such as Z-SEP and SEP. Simulation results show that IZ-SEP is an energy-efficient protocol and it outperforms the existing parent protocols in terms of network lifetime, stability period, throughput, and average residual energy