为解决目前头盔显示器中存在佩戴舒适性差等问题，提出采用无线通信技术来代替有线电缆。以机载狭小座舱环境为研究对象，通过分析无线信号在机载座舱空间内的传输特性，以Jakes模型为基础，结合飞行员头部运动规律，提出了一种新的多普勒频移表达式，并通过Matlab对改进的Jakes模型进行仿真分析，从仿真结果看出，改进Jakes模型的自相关函数曲线和互相关函数曲线与理论值更加接近，具有更好的二阶统计特性，可以应用于机内无线信道建模研究。

叉指数优化选择是传统MMSE-Rake(最小均方差Rake接收机)算法的重要组成部分, 广泛应用于UWB(超带宽) Rake接收机中。为了提高在低速传输条件下UWB系统对多径信号接收的快速识别能力, 提出了一种基于优化抽头系数的MBER(最小误比特率)改进算法, 该算法可在不降低多径分辨率的前提下, 通过简化Rake叉指数实现快速定位。仿真结果表明, 在低速CM3(NLOS信道)和CM4(特殊情况下NLOS信道)多径模拟信道传输条件下, 改进后的算法在性能上优于传统MMSE-Rake算法, 不仅降低了Rake接收机的复杂度, 还提高了信号接收的实时性。

Multipath-induced pulse broadening in a non-line-of-sight (NLOS) optical scattering channel is investigated. Expressions for impulse response and digital signal-to-noise ratio (DSNR) penalty induced by intersymbol interference (ISI) of a NLOS ultraviolet (UV) scattering communication are introduced based on a single-scattering model, and simulated results for some typical atmospheric condition and configuration of geometry are given in the paper. It is shown that the multipath dispersion is one of the most important factors limiting the system performances, and return-to-zero (RZ) format is more suitable for the optical scattering communications than non-return-to-zero (NRZ) format. The method proposed here can be used to predict available bandwidth and data rate of the communication system operating in a NLOS optical scattering channel.