低功耗物联网中远距离并发传输关键技术研究

The Low Power Wide Area Network (LPWAN) has advantages of low power and long range compare with traditional wireless communication technology, and therefore, LPWAN has great potential for applications in large-scale Internet of Things (IoTs). However, the LPWAN encounter the bottlenecks of low throughput and poor universality since they rely on narrow bandwidth signal. Based on the above factors, this project explores the method of combining wireless signal feature analysis and node state estimation to achieve long distance, high throughput, and robust data-based concurrent transmission for LPWAN. Researching the matching relationship between the physical characteristics of concurrent signals and the sending nodes, designing feature signals based on frequency offset. And then propose concurrent signal decoding method based on feature analysis to improve concurrent transmission throughput. By constructing node state estimation model, we can guarantee the robust of transmission method through controlling concurrent transmission. The project will design and implement a LPWAN data concurrent transmission verification platform and prototype system for typical applications and complex application scenarios. The scientific essence lies in exploring the inner relationship among the signal physical properties and signal decoding in LPWAN, network throughput and transmission robustness. The results will provide valuable theoretical foundations and technical reference for LPWAN data transmission applications. It has major implications for promoting large-scale IoTs applications.

低功耗物联网远距离传输技术与传统无线通信技术相比拥有低功耗、远距离等优势，因此在大型物联网系统中应用潜力巨大。但现有低功耗远距离的传输技术由于依赖窄带信号因此面临着网络吞吐低、难以普适的困境。对此，本项目探索采用无线信号特征分析与感知节点状态估计相结合的方法，实现低功耗物联网远距离、高吞吐、高鲁棒数据并发传输。研究并发信号物理特征与发送节点间的匹配关系和基于频率偏移的特征信号设计，以及基于特征分析的并发信号解码方法，提高并发传输吞吐率；研究感知节点状态估计模型及其并发传输优化控制方法，提高并发传输的鲁棒性；针对典型应用和复杂应用场景，设计实现低功耗物联网数据并发传输验证平台和原型系统。其科学实质是探索低功耗远距离无线信号物理特征与信号解码与网络吞吐和传输鲁棒性之间的内在联系，研究成果将为低功耗物联网远距离数据传输应用提供理论依据与技术参考，对推动大规模物联网应用有主要意义。

本项目针对现有低功耗物联网远距离数据传输面临理论与实践应用性能差距大、网络整体协议缺乏对并发传输有效控制等相关问题，研究了在多种网络环境下突破低功耗物联网远距离数据传输性能极限的方法，以及并发传输控制方法等。项目发现了并发传输中存在的上下行链路冲突的问题，通过构建并发传输模型寻找最优发送参数，在保证网络有效吞吐的前提下进一步降低了节点的能耗。项目深入分析了低功耗物联网信号的调制解调特性，通过设计可解调无线信号的神经网络模型，将其应用到干扰较大的网络环境中，从而保证解调准确性增强信号的抗干扰性能，并通过降低发送信号长度和采样频率来进一步降低了节点能耗，提高了网络吞吐，最终实现了低功耗物联网性能的突破。在物联网数据传输路由策略方面，项目组对多网关场景中网关的工作状态进行了分析，在进行路由选择时同时考虑网关的性能，保证数据传输最后一跳的可靠性。本项目的多个成果先后发表在IEEE Internet of Things Journal, Computer Networks, 软件学报等国内外期刊上，申请相关发明专利4项。数据传输方法是物联网应用正常运行的基础，本项目的研究对低功耗远距离物联网的发展和应用有着重要的意义。