EZS-SEP: A hybrid efficient zonal stable election routing protocol with SOM-based node deployment for heterogeneous wireless sensor networks

Wireless Sensor Networks (WSNs) are widely utilized in numerous applications for data collection and monitoring; however, their performance is often limited by energy constraints and the need for efficient data transmission. Network stability largely depends on node energy utilization, clustering strategy, and data transmission methods. In this work, an energy-efficient routing protocol is introduced for heterogeneous WSNs, referred to as Efficient Zonal Stable Election Routing Protocol with SOM-based node deployment (EZS-SEP). The proposed protocol aims to enhance network stability, area coverage, throughput, and overall performance by employing a hybrid communication technique and a self-organizing map (SOM) for node deployment. The WSN is divided into distinct zones based on energy levels. Normal nodes with lower energy are placed near the Base Station (BS), while intermediate and advanced nodes are positioned farther from the BS. This arrangement ensures optimal energy utilization. The Cluster Head (CH) selection mechanism of the protocol considers several critical factors, including residual energy, distance from the BS, and average node energy, ensuring that higher-energy nodes with favorable proximity are elected as CHs. Simulation results demonstrate that EZS-SEP outperforms conventional heterogeneous clustering protocols in terms of stability period, network lifetime, and throughput. Therefore, for real-world WSN applications requiring energy efficiency and reliable coverage, EZS-SEP is a suitable solution. It improves stability by 34%, 63%, 31%, and 174% compared to ESEP, P-SEP, Z-SEP, and LEACH, respectively. This study further evaluates the performance of EZS-SEP under different scenarios, including variations in BS position and initial energy levels, demonstrating its robustness across diverse network conditions.