Mobile data gathering and energy harvesting in rechargeable wireless sensor networks

In this paper, we study the joint data gathering and energy harvesting (JoDGE) problem in rechargeable wireless sensor networks (RWSNs) with a mobile sink. In RWSNs, the sensor nodes are equipped with RF circuit to harvest energy from a mobile sink that moves along a pre-defined path, and at the same time, transmit gathered sensor data to the sink. Given that the consumed and harvested energy at a sensor node is proportional and inversely proportional to the square of transmission distance, a far-relay approach is proposed to select the sensor nodes closer to the path to assist the data transmission of the farther sensor nodes. Under the far-relay approach, we formulate a network utility maximization problem (NUM), and propose an optimal scheduling scheme (Opt JoDGE), which jointly considers the power allocation, relay selection and time slot scheduling policies. By employing the Lyapunov drift theory, a near optimal buffer-battery-aware adaptive scheduling (NO-BBA) scheme is further proposed, in which the run-time status of the data buffer and battery are utilized. Extensive simulation experiments validate the feasibility and performance of JoDGE and NO-BBA. The results show that the performance of NO-BBA is close to that of Opt-JoDGE, especially when a certain delay is tolerable. (C) 2019 Elsevier Inc. All rights reserved.