无线体域网中以非线性技术抑制强窄带干扰的超宽带接收机的研究

Since UWB systems must share the frequency band with other narrowband wireless communication systems, effective suppression of the strong narrowband interferences from these systems becomes the main issue for the design of a low-power and low-complexity pulse UWB receiver used in the wireless body area network. UWB signal has the characteristics of large bandwidth and a very short pulse; and compared with a narrow-band signal, it has greatly different random characteristics. These special characteristics of the UWB signals may be turned into performance advantages when non-linear signal processing technology is employed for suppression of the strong narrowband interference. Therefore, the use of the non-linear signal processing technology for UWB receiver is a totally new technique in the research and has its significance in theory. Our preliminary research result has shown that the non-linear signal processing technology can effectively suppress the strong narrowband signal interference to the UWB receiver. However, there are still many theoretical problems and technical challenges remained to be solved..For this purpose, combined with the application background of the wireless body area network, the project intends to carry out the following studies: the working mechanism and design criteria of the non-linear signal processing technology of UWB receiver; the performance analysis and parameter optimization of UWB system based on the non-linear signal processing technology; the architecture design of the receiver and optimization methods applied to the non-linear signal processing technology. Successful implementation of this project will provide a solid theoretical basis for the application of the non-linear signal processing technology to the UWB receiver of the wireless body area network, and it will has great significance both in theory and engineering applications.

由于超宽带必须与其它通信系统共享频段，在功耗和复杂度受限的条件下有效抑制强窄带干扰是设计用于无线体域网的超宽带接收机的核心研究问题。脉冲UWB信号具有带宽大且时域能量集中的特点，与窄带信号有着截然不同的随机特性，采用非线性信号处理技术来抑制强窄带干扰有望充分利用超宽带信号这种独特的特性并将其转化为性能优势。因此，将非线性信号处理技术用于UWB接收机是一种全新的研究尝试，有着极其重要的理论意义。本项目的前期预研表明非线性信号处理技术能有效抑制脉冲超宽带接收机的强窄带干扰，但仍有许多亟待解决的理论问题。为此，本项目拟结合无线体域网的应用背景开展以下研究：超宽带接收机中非线性信号处理技术的工作机理和设计准则；基于非线性信号处理技术的超宽带系统的性能分析和参数优化；适用于非线性信号处理技术的接收机结构设计和优化方法。项目的实施将为非线性信号处理技术在无线体域网超宽带接收机的应用提供坚实的理论依据。

本项目主要结合无线体域网的应用背景开展了基于非线性信号处理技术的脉冲超宽带接收机的研究。项目的主要研究内容和结果包括以下几个方面：.1. 通过理论推导得出超宽带接收信号经过Teager-Kaiser算子（Teager-Kaiser operator，TKO）和平方律（Square law，SL）两种非线性技术处理后的频域表达式，通过分析非线性处理后输出信号各分量的频域分布特性，揭示了非线性信号处理技术通过对各个信号分量不同的频谱搬移和滤波处理来实现接收机性能提升的工作机理，并给出了非线性信号处理技术的选择和设计准则。.2. 为了实现非线性信号技术的理论性能分析，创建了非线性TKO技术的理论分析框架，得出了非线性TKO和非线性平方律技术对IR-UWB接收信号SINR（Signal to interference plus noise ratio）的处理增益公式，实现了对非线性TKO技术性能的定量分析。根据理论分析得出的公式，明确了各种系统参数选择对非线性信号处理技术性能的影响，为非线性信号处理技术在IR-UWB系统的应用提供了理论依据。.3. 最后，提出了基于非线性差方检测技术接收机和基于非线性平方律技术的多通道能量检测接收机两种改进的采用非线性信号处理技术的接收机结构。仿真结果表明，两种改进的接收机相对于传统的能量检测接收机有明显的BER性能提升和抗窄带干扰性能，并且比采用非线性平方律技术的传统PPM-ED接收机具有更好的BER性能和抑制强窄带干扰能力。.通过本项目研究，对采用非线性信号处理的超宽带系统的工作机理和系统设计有了更深入的理解，研究中取得的研究结果可为非线性信号处理技术在无线体域网超宽带接收机的应用提供坚实的理论依据。