Multi-User Communications in Non-Gaussian Channels

本计画将探讨多重存取的问题 通过非高斯信道的扩频通信 调变 这在很大程度上是因为 现代城市无线电网络必须在复杂多变的 噪声环境通常由脉冲、非 高斯人为和自然噪声源。 非高斯 现在已知在许多情况下存在干扰，并且 它们可以大大降低传统数字系统的性能， 通信系统。 这项研究的总体目的是开发新的 适用于在这种情况下操作的多用户系统的设计方法 非高斯信道 本研究可分为两部分 要考虑的主要任务。 有发展， 时间和相位同步器;以及“最佳” 非高斯非线性相干扩频接收机 噪声 在许多应用中，在存在非高斯 噪声源，脉冲和瞬态特性， 噪声表明接收器结构中的非线性可以 通过降低有效噪声功率， 由噪声脉冲引起的大电压偏差。 因此 提出了设计和分析性能的优化， 同步和相关的无记忆非线性 接待 在结构中引入记忆的可能性 接收器也将被探索。 预计该 本研究成果将在城市中得到广泛应用。 军用移动的无线电网络和低频 通讯

This project will investigate the problem of multiple-access communications through non-Gaussian channels via spread-spectrum modulation. It is motivated in large part by the fact that modern urban radio networks must operate in complex and variable noise environments that are often dominated by impulsive, non- Gaussian man-made and natural noise sources. Non-Gaussian disturbances are now known to be present in many situations, and they can greatly reduce the performance of conventional digital communication systems. The overall purpose of this research is to develop new design methods suitable for multiuser systems operating in such non-Gaussian channels. The study can be divided into two principal tasks to be considered. There are the development of time and phase synchronizers; and the design of "optimum" nonlinear, coherent, spread-spectrum receivers in non-Gaussian noise. In many applications, in the presence of non-Gaussian noise sources, the impulsive and transient characterisitics of noise suggest that a nonlinearity in the receiver structure can significantly reduce the effective noise power by reducing the large voltage deviation caused by noise impulses. Thus it is proposed to design and analyze the performance of optimum memoryless nonlinearities for synchronization and correlation reception. Possibilities of introducing memory in the structure of receivers will also be explored. It is anticipated that the results of this study will find widespread application in urban and military mobile radio networking and low frequency communications.