A Comprehensive Survey of LEACH Protocol and Its Advancements for Energy-Efficient Wireless Sensor Networks
Low-Energy Adaptive Clustering Hierarchy (LEACH) is one of the earliest and most influential hierarchical routing protocols developed for Wireless Sensor Networks (WSNs). It was designed to reduce energy consumption by organizing sensor nodes into clusters and periodically rotating the cluster-head role among nodes to balance energy usage and extend network lifetime. This survey presents a comprehensive review of the LEACH protocol, describing its architecture, clustering mechanism, setup and steady-state phases, and data aggregation process. The paper examines the key advantages of LEACH, including energy efficiency, scalability, and reduced communication overhead, while also discussing its limitations such as random cluster-head selection, uneven cluster distribution, and limited performance in heterogeneous or large-scale networks. Furthermore, the survey summarizes the major LEACH variants proposed to overcome these challenges, including centralized, multi-hop, mobile, and energy-aware extensions. A comparative overview of these variants is provided based on their design objectives and performance improvements. Finally, the survey highlights current research trends involving LEACH integration with Internet of Things (IoT) applications, machine learning techniques, artificial intelligence, and energy-harvesting technologies, while identifying future research directions for improving reliability, scalability, security, and overall network performance in next-generation wireless sensor networks.