工业无源网络的低功耗高可靠感知和传输方法研究

Battery-free networks or passive networks，can harvest energy from the environment to support their functions of sensing, controlling, computing, communications, and networking. As a key technology to solve the energy supply bottlenecks of the Internet of Things, more attention is paid to them recently. This project aims at solving the problem of low perceptual and transmission reliability of battery-free networks. We study low-power high-reliability industrial battery-free networks based on OFDM signal backscatter communication networking, multi-source integration and distributed beamforming wireless power supply. The specific research contents include: (1) Research on low-power and high-reliability new backscatter communication technology and sensor-transmission integrated low-power high-precision sensor theory and design method to reduce the energy consumption. (2) Study the multi-source energy harvesting maximizing method and distributed beamforming wireless energy supply theory to improve the harvesting power of battery-free nodes. (3) Using the diversity of distributed receivers to study interference cancellation techniques in backscatter communication networks. A unified real-time scheduling problem of distributed beamforming energy transmission, downlink communication and uplink backscatter communication in a multi-source converged network will be studied, and a reinforcement learning based optimizer search algorithm will be designed to improve the real-time performance of network scheduling. The project research and its achievements will enrich the research content of battery-free networks and promote the application of battery-free networks in industrial environments.

无源网络从环境中获能以支撑其感控、计算、通信和组网的功能，作为解决物联网节点能量供应瓶颈的关键技术备受关注。本项目针对目前无源网络感知和传输可靠性低的问题，研究基于多源融合、分布式波束成形无线供能保障的，基于OFDM信号反射通信组网的低功耗高可靠工业无源网络。具体研究内容包括：（1）研究低功耗高可靠的新型反射通信技术和感传一体的低功耗传感器原理和设计方法，以降低无源节点的能量开销。（2）研究多源融合节点最大化获能方法和分布式波束成形无线供能理论，以提高无源节点的获能功率。（3）利用分布式接收端多样性，研究反射通信网络的干扰消除技术。研究多源融合网络的分布式波束成形能量传输、下行通信和上行反射通信统一实时调度问题，和基于强化学习的优化器搜索算法，以提高工业无源网络调度的实时性。该项目研究及其成果将丰富无源网络的研究内涵，对开拓无源网络在工业环境中的应用有重要意义。

反向散射通信技术作为一种超低功耗的新兴无线通信技术，被应用于无源网络，与传统无线通信——射频通信不同，它不主动发射电磁波信号，而是反射环境中的电磁波信号进行无线通信。由于减少了主动发射电磁波的射频通信硬件模块，其功耗是射频通信的千分之一，可以应用于从环境收集能量（光能、电磁波能、热能等）的无源网络。由于WiFi信号是开放环境中最普遍使用的信号，本项目研究WiFi信号的无线反射通信。最新的WiFi反向散射系统都没有解决开放环境中WiFi信号的随机间歇间断的特性，这导致反向散射通信的可靠性较低。为了解决这个问题，我们在RS编码之上提出使用喷泉编码来增强通信传输可靠性，该方法能够在开放环境通过WiFi信号实现较可靠的反向散射传输。我们通过在环境中部署一台OFDM信号发射器不断检测空中某一信道中的能量，来改善信号分布，将解码成功率提升到原来的约4.5倍。我们还设计了相应的反射标签，并使用Wireshark分析WiFi，通过喷泉编码（LT）的反向散射通信仿真实验和对比实验，提高了编解码速度，还将传输成功率提高了23%。