无线信能同传技术中的波束成型设计

The Internet of Things (IoT) is one of the most important areas for the Thirteenth Fiver-Year Plan in China, and Energy Harvesting is a key problem for IoT. Since the number of sensors in modern wireless sensor networks (WSNs) is huge and some positions of the sensors are difficult for maintenance, it is costly and unrealistic to use the traditional method – replacing batteries. Although the wind and solar may solve this problem, they still cannot be implemented in practice due to uncertainties of the weather. Because radio frequency (RF) based charging can overcome these difficulties, it has great potentials for IoT. Simultaneous wireless information and power transfer (SWIPT) is an emerging technology, which uses RF signal to transfer information and power simultaneously in WSNs. This project will consider one of the most import problem – the energy issue in the application of SWIPT by using beamforming technology. On one hand, it is required to increase the harvest energy. On the other, the energy cost has to be reduced. More specifically, this project will focus on two key problems – computational complexity and robustness in the beaformer design of SWIPT. Low complexity algorithms will be developed to reduce the energy cost of signal processing, and robust algorithms will be developed to increase the harvest energy in the presence of channel estimation error.

物联网是国家“十三五”规划中重点资助和发展的方向，而能量获取技术是物联网发展的核心问题。由于现代无线传感网络中传感器数量巨大，且很多传感器的位置不易进行人工维护，传统的更换电池的方式在成本和实现上都面临新的挑战。虽然太阳能和风能等可再生能源可以解决这些问题，但是由于它们的不可控性而很难得到推广。由于无线电充电可以克服上述困难，因此它在未来物联网的发展中占有重要的地位。无线信能同传技术（SWIPT）是一项新兴技术，它使用无线电在无线传感网络中同时进行信息和能量的传输。本项目将关注无线信能同传技术中最重要的能量问题，通过采用波束成型技术，一方面提高能量获取，另一方面降低系统能量的消耗。具体而言，本项目将聚焦于无线信能同传下波束成型技术中的两个关键问题-计算复杂度和鲁棒性，一方面设计低复杂度的算法减小信号处理中的能量消耗，另一方面设计鲁棒算法增加在存在信道误差的情况下的能量获取。

能量获取是物联网技术中的核心问题。由于当前无线传感网络中传感器数量巨大，且很多传感器的位置不易进行人工维护，传统更换电池的方式在成本和实现上都面临新的挑战。虽然太阳能和风能等可再生能源可以解决这些问题，但是由于它们的可控性差而很难得到推广。由于采用无线电充电的方式可以克服上述困难，因此它是未来物联网领域的一项关键技术。信能同传技术是一项新兴科技，它使用无线电在无线传感网络中同时进行信息和能量传输。波束成型技术可以改变电磁波在空间的分布，而形成特定指向的“波束”。中继技术可以增大信号的传递距离，可以用来扩大信能同传技术的覆盖范围。本项目结合波束成型技术和中继技术，设计了在中继节点需要无线电功能的情况下，发送端和中继端编码的联合优化，具体贡献主要体现在：（1）在不借助可再生能源和更换电池的情况下，提高物联网中传感器的寿命；（2）扩大了物联网的覆盖范围。依托本项目共发表SCI检索论文14篇，授权专利5项，培养硕士生3人。