环境反向散射通信系统的信道估计和信号检测理论研究

Ambient backscatter is a new communication technology that utilizes ambient wireless signals to enable battery-free tags to communicate with readers. It can liberate tags and sensors from maintenance-heavy batteries, and thus has significant commercial value. Currently only several prototypes are given to demonstrate its possibility and the corresponding communication theories for ambient backscatter are to be developed. This project will focus on the channel estimation and signal detection theories for wireless communication systems that utilize ambient backscatter. Firstly, theoretical models for ambient backscatter signals and systems will be proposed based on fully investigation of statistical properties of ambient backscatter signals in both flat-fading and frequency-selective channels. Secondly, new estimation algorithms will be designed to obtain some constructed channel parameters since straight channel coefficients are not available. Thirdly, detection algorithms will be suggested to recover the transmitted symbols hidden in ambient and backscattered signals. Moreover, to evaluate the system performance, bit error rate (BER) and throughput for ambient backscatter systems will be derived in closed form. In addition, minimization of BER and maximization of throughput will be performed to obtain optimal detection thresholds and optimal parameters for resource allocation such as the number and power ratios for training symbols. Finally, a hardware testing platform will be developed to realize the suggested estimation and detection algorithms and corroborate our theoretical findings. Our proposed studies can provide theoretical supports for new generation of RFID products and sensor technologies, and our developed hardware testing platform can serve as a good reference for new commercial applications for Internet of Things.

环境反向散射技术是利用周围环境中已有的无线信号，采取转发或不转发该信号的方式分别代表0和1比特，以实现标签和读写器之间的通信。该技术无需能量源产生信号，能让传感器摆脱电池的束缚，是一种全新的通信方式，具有重大的应用价值，可能带来新一代的RFID革命。然而，作为一个新生事物，目前只有实验指出了其可行性，相关的通信理论还有待完善，亟需研究。本项目聚焦于环境反向散射通信系统中的信道估计和信号检测理论，首先透彻研究环境反向散射信号和信道的统计特性，建立平坦衰落信道和频率选择性衰落信道下的环境反向散射信号及系统的数学理论模型，在此理论模型的基础上设计信道估计和信号检测算法，并理论分析估计检测性能和系统吞吐量，最后利用硬件测试平台实现估计和检测算法并加以验证。本项目能为新一代RFID产品和传感器技术的发展提供理论支撑，搭建的硬件测试平台对产品商用化有很好的借鉴和参考价值，有力推动物联网的发展。

环境反向散射技术是利用周围环境中已有的无线信号，采取转发或不转发该信号的方式分别代表0和1比特，以实现标签和读写器之间的通信。该技术将已有的无线信号作为能量源来通信，是一种全新的通信方式，能让传感器摆脱电池的束缚，具有重大的应用价值。本项目聚焦于环境反向散射通信系统中的信道估计和信号检测理论，首先透彻研究了环境反向散射信号和信道的统计特性，建立平坦衰落信道和频率选择性衰落信道下的单天线和多天线标签环境反向散射信号及系统的数学理论模型，在部分或者没有导频的情况下分别设计了信道估计和信号检测算法，理论分析优化检测误比特率和系统吞吐量。设计的算法和性能分析理论能对物联网的无源传感器设计与实现有实践指导意义和重要参考价值。该项目累计培养博士6名（顾琪、范典、尤嘉、刘杨、陈晨、赵文晶），发表SCI检索论文23篇。