I. Introduction
With the rapid development of Micro Electro-Mechanical Systems (MEMS), the research process of wearable devices has greatly accelerated. Accordingly, the coverage of wireless body area network (WBAN) has been greatly expanded [1]. As a wireless network that specific to the human body, its sensor nodes can collect various physiological parameters from human, and send data to an access point (AP) [2]. Due to the limitations of micro-sensors (such as limited battery capacity), a major challenge is how to achieve sustainable work of WBAN. In [3], an energy-efficient networking technique is designed based on the concept of energy harvesting small cell networks (EH-SCNs).