Moraes Celso, Myung Sunghee, Lee Sangkeum, Har Dongsoo
Cho Chun Shik Graduate School of Green Transportation, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
Sensors (Basel). 2017 Jan 10;17(1):122. doi: 10.3390/s17010122.
Provision of energy to wireless sensor networks is crucial for their sustainable operation. Sensor nodes are typically equipped with batteries as their operating energy sources. However, when the sensor nodes are sited in almost inaccessible locations, replacing their batteries incurs high maintenance cost. Under such conditions, wireless charging of sensor nodes by a mobile charger with an antenna can be an efficient solution. When charging distributed sensor nodes, a directional antenna, rather than an omnidirectional antenna, is more energy-efficient because of smaller proportion of off-target radiation. In addition, for densely distributed sensor nodes, it can be more effective for some undercharged sensor nodes to harvest energy from neighboring overcharged sensor nodes than from the remote mobile charger, because this reduces the pathloss of charging signal due to smaller distances. In this paper, we propose a hybrid charging scheme that combines charging by a mobile charger with a directional antenna, and energy trading, e.g., transferring and harvesting, between neighboring sensor nodes. The proposed scheme is compared with other charging scheme. Simulations demonstrate that the hybrid charging scheme with a directional antenna achieves a significant reduction in the total charging time required for all sensor nodes to reach a target energy level.
为无线传感器网络提供能量对其可持续运行至关重要。传感器节点通常配备电池作为其运行能源。然而，当传感器节点位于几乎无法到达的位置时，更换电池会产生高昂的维护成本。在这种情况下，使用带有天线的移动充电器对传感器节点进行无线充电可能是一种有效的解决方案。在对分布式传感器节点进行充电时，定向天线比全向天线更节能，因为偏离目标辐射的比例更小。此外，对于密集分布的传感器节点，一些电量不足的传感器节点从相邻电量过剩的传感器节点获取能量可能比从远程移动充电器获取能量更有效，因为这会因距离较短而减少充电信号的路径损耗。在本文中，我们提出了一种混合充电方案，该方案将使用定向天线的移动充电器充电与相邻传感器节点之间的能量交易（例如传输和获取）相结合。将所提出的方案与其他充电方案进行了比较。仿真表明，带有定向天线的混合充电方案可显著减少所有传感器节点达到目标能量水平所需的总充电时间。
