物联网无线通信的并发传输技术研究

Low-power wireless communications fully fit the attributes of Internet of Things’ devices including small-size, energy-saving, and mobility. Naturally, they hold the dominate position in current communication patterns in Internet of Things. With the development of Internet of Things to large scale, the dilemma has produced between large amounts of access requirements and the limited bandwidth resource in low-power wireless communications, which lead to the prevalence of collisions and data loss. Existing techniques either avoid the collisions from time dimension or provide multiple access by frequency and code division. In this project, we plan to study a novel concurrent transmission technique that embraces the collisions and direct resolves the data from the collisions. Our main research methodology is a bottom-up system design: The physical-layer innovation is the core of this work. Digging the baseband signal features, we design the collision separation modules taking advantage of new angles such as sampling rate and encoding characteristics; Then, we investigate the link layer and network layer protocols supporting the physical layer design in order to optimize the performance in networks; In the application layer, we design the data reconstruction method based on the compressed sensing, as the compensation for the physical layer’s separation technique; In addition, we derive the basic theory of concurrent transmission and the theoretical results could be used to guide the practice; In the end, we build the prototype using the software defined radio platforms to conduct experiments in real scenarios and evaluate the performance of our design. The goal of this project is to realize the concurrent transmission system, which could further improve the access amount and throughput in low-power wireless communications. The achievements of our project will provide both theoretical and technical supports for the development of large-scale Internet of Things.

低功耗无线通信充分契合物联网设备的小型、节能、移动等属性，因此占据着物联网通信的主导地位。随着物联网向大规模发展，海量的接入需求和低功耗无线通信的有限带宽资源产生矛盾，导致冲突和数据丢失普遍存在。现有技术以冲突避免为主，或者通过频分、码分复用提供多址接入。项目拟研究并发传输技术，允许冲突发生，并且直接解析冲突获取数据。主要研究方法是自下而上的系统化设计：以物理层创新为核心，针对低功耗无线通信的基带信号特征，从采样率、编码特性等新的维度挖掘冲突分离的潜能；辅以链路层和网络层协议设计，优化并发传输下的网络性能；在应用层研究基于压缩感知的数据重构方法，作为物理层分离技术的补偿；形成并发传输的基本理论体系，通过理论研究指导实际开发；搭建基于软件无线电的原型系统，进行实验和性能评估。研究目标是实现并发传输技术，切实提高物联网的接入量和网络吞吐量。成果将为物联网大规模发展提供理论和技术支撑。

从科学意义方面，并发传输技术发掘物联网无线通信的特点和潜力，以香农定理的带宽利用率上限为理论指导，另辟新径探索无线通信中经典的冲突问题，是现有研究的深化和拓展。从应用前景方面，并发传输技术是一项针对物联网无线通信的冲突解决方案，对现有产品兼容性高，产业化成本较低，也可以和其它冲突解决方案协作使用。并发传输技术的实现将实质性增加物联网设备接入量，为推广大规模物联网应用提供接入支持。.本项目是一项面向物联网并发传输技术的研究，从应用中提炼，最后反馈到应用中去。主要研究内容包含五个方面。一、通过物理层设计直接分离并发传输导致的冲突信号，包括冲突检测模块和两项核心模块：采样分离和编码分离。二、以物理层创新为基石，设计配套的上层协议，包括在线并发能力估计、MAC协议、路由协议，完善并发传输技术的设计体系。三、在应用层设计基于压缩感知的重构方法，用于补偿并发传输的部分丢失。四、为并发传输建立数学模型，包括传输冲突模型和冲突分离模型，基于模型进行并发传输情况下并行能力、吞吐量和误码率的理论分析和推导。五、设计应用示范原型系统和评估指标，通过原型系统试验和大规模仿真来比较并发传输技术和现有技术的性能，同时和理论推导结果相比较，以此来检验和完善。研究内容系统地解决物联网无线传输的冲突问题，保障网络连通性和数据传输可靠性。.项目团队在重要的国际学术刊物和会议上发表论文45篇（期刊31篇，会议14篇），其中CCF A类8篇，B类17篇。获国际会议最佳论文奖7篇，国际会议最佳演示奖1项，国内会议最佳论文奖1项。项目负责人孔令和入选2019年度长江学者青年学者项目、2019年上海市自然科学二等奖、2019年上海市东方学者特聘教授计划、2018年杨元庆教育基金优秀青年教师。执行期内授权发明专利5项，已转化2项，申请但尚未授权发明专利9项。