Efficient Green Protocols for Sustainable Wireless Sensor Networks

Nowadays, wireless sensor networks (WSNs) are widely adopted by many civil/military applications. However, due to the limited capacity of the built-in battery, the lifetime of the sensor is limited, which in turn affects the working time of the whole system. Therefore, the limited energy supply is the most direct and critical constraint to maintain the long-term and efficient operation of the system. Accordingly, reducing energy consumption/improving energy efficiency is an essential prerequisite for designing a sustainable WSN. To address this problem, many approaches have been proposed. To help readers fully understand the techniques/methods in this area of research, we present a taxonomy of the existing energy-efficient strategies for achieving sustainable WSNs. We first introduce some basic concepts and assumptions commonly adopted in energy-efficient WSNs designs. Then, we discuss existing approaches designed for conventional WSNs (consisting of static nodes or nodes with limited mobility) from five aspects: clustering-based schemes, node deployment strategies, node scheduling algorithms, energy-efficient routing schemes, and energy-efficient joint designs. We compare these schemes and highlight their strengths and drawbacks. Additionally, we discuss state-of-the-art approaches relying on some emerging techniques, e.g., high-mobility data collectors, energy-harvesting techniques, etc. Finally, we conclude the paper and present some open challenges.