人体中心可穿戴无线通信信道建模及其应用研究

Wearable wireless communications of human body, one of inevitable trends of the future development of personal wireless communications technologies, has very broad application prospects in the field of care testing, soldiers positioned recognition and so on. However, recent researches indicate that a key obstacle with fundamental significance of research and development is the lack of wearable wireless communication system in the center of the body channel model. To this end, the project is proposed to explore the physical mechanism of the interaction between electromagnetic waves and human reveals wearable electromagnetic wave propagation in wireless communication systems and to establish the corresponding channel model. Strong coupling, which is between antenna and human body, make the human body as a component of an antenna. Also, this leads to a strong near-field coupling characteristics of the body surface electromagnetic wave propagation between nodes of the body. The project will take full account of that characteristic, through theoretical analysis, numerical simulations and experiments, using traditional far field channel models for reference, the semi-deterministic channel model of surface-surface and surface-body wireless communication link, which indicates the characteristic of strong near-field coupling and the relationship between node locations and body posture, would be constructed. For the characteristic of each channel, the new technique of antenna design which improves the channel gain would be investigated. The optimal distribution of surface wireless nodes, the improvement of system reliability and efficiency and the optimal performance design of the wearable system would be investigated.

人体中心可穿戴无线通信由于在医疗护理检测、士兵定位识别等领域具有十分广阔的应用前景，是未来个人无线通信技术发展的必然趋势之一。但研究现状表明，其研究与发展的一个关键且具有基础性意义的障碍就是缺少适用于人体中心可穿戴无线通信系统的信道模型。为此，本项目提出探索电磁波与人体相互作用的物理机制，揭示可穿戴无线通信系统中的电磁波传播规律并建立相应信道模型。天线与人体强耦合，使得人体成为了天线组成部分，导致了人体表面、体内各节点间的电磁波传播具有强的近场耦合特征。项目将充分考虑这一特点，通过理论分析、数值模拟以及实验等手段，借鉴传统远场信道模型，建立反映强近场耦合特征、全面考虑节点位置及人体姿态等因素的人体表面－表面、表面－体内无线通信链路半确定性信道模型；针对各信道特点，研究能提高信道增益的天线设计新技术；探索人体表面无线节点的最佳分布，增强系统可靠性与效率，同时完成对可穿戴系统的最优性能设计。

在自然科学基金的资助下，本项目开展了以下的研究工作：1）人体表面无线节点间电磁波传播特征研究。我们深入分析了人体表面电波传播的特点，以及如何有效提高传播增益的途径。2）天线源类型与人体作用的研究。我们全面的分析了不同天线源类型对人体的影响，以指导今后的天线设计。3）简化人体组织模型的研究。人体是一个由各种组织和器官组合而成的复杂系统，不同组织和器官的电磁特性相差极大，这对于天线的设计带来的极大的挑战。同时，考虑到设计的实际情况，没必要在最初的设计中就使用完整的人体组织模型。这就需要对人体模型进行一定程度的简化。为此，我们研究单层人体组织模型，多层人体组织模型等一系列相关模型，力求找到模型精度与设计时间的平衡点。4）适用于人体表面节点间通信的天线研究。可穿戴天线是人体中心无线通信的核心器件。为此，本课题组提出一种基于高阻表面的紧凑低剖面天线，以及顶部加载方形贴片的方向图可重构单极子天线。5）植入式天线的研究。植入式天线是无线数据遥测系统中极其重要的一部分。为此，我们设计了多种植入式天线，它们分别是具有圆极化特性的植入式天线，植入式MIMO天线，以及基于CMOS技术的植入式天线。