Classification of Energy-Efficient Routing Protocols for Wireless Sensor Networks

In recent years, research on Wireless Sensor Networks (WSNs) has become one of the main topics in electronic and computer fields. Since, the WSNs include many low cost and low power sensor nodes and battery replacement in harsh environments is usually impossible, an energy-efficient paradigm for all layers of protocol stack specially routing schemes is necessary to prolong the sensors' lifetime. In this paper, we first specify the sources of energy consumption in a typical sensor node, and then we classify the energy-efficient routings into three main categories such as flat, hierarchical, and geographic mechanisms based on underlying network structure. However, protocols employing simultaneous schemes such as bio-inspired methods, quality of service, multi-path and querybased manners are also discussed. In this taxonomy, special attention has been devoted to the energy-aware QoS-based and bio-inspired routing algorithms which have not yet obtained much consideration in the literature. Moreover, each class covers a variety of the state-of-the-art routing and cross-layer protocols, which motivate potential ideas for future works. Finally, we compare these mechanisms and discuss open research issues.