【作者】 岳光荣；

【导师】 李少谦；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2006， 博士

【摘要】 超宽带无线通信作为无线通信领域的新兴技术，在近年来受到了越来越多的关注。基于冲激无线电技术的超宽带系统具有结构简单、成本低、处理增益高、功耗小、时间分辨率好等优点，使得这种新型的无线电技术在未来的中、短距离高速无线通信中扮演重要角色，具有十分广泛的应用前景。本文首先全面介绍了超宽带无线通信的发展历史和研究现状，分析了超宽带信号的特点，并列出了目前该领域仍有待解决的一些基本问题，指出了本文研究的内容。随后介绍了超宽带冲激无线电系统的基本调制方式和常用的信道模型。从理论上分析了超宽带跳时脉冲位置调制信号和跳时脉冲幅度调制信号在确定性多径信道的误码率性能。并指出在某些确定性多径信道条件下，对于脉冲位置调制信号，由于存在多径分量间的干扰，采用传统的接收机结构将导致不同数据符号的误码率存在不平衡现象。针对这种现象，我们提出了两种解决方法，一种是采用动态判决门限的方法，另一种是采用对称编码调制的方法。理论分析与仿真证明，这两种方法都能有效地消除多径环境中的误码率不平衡现象，比较而言，平衡编码方法具有实现的简单性以及在对信道变化、RAKE接收机信道估计以及合并方式的稳健性。分析了不同调制方式的超宽带信号的抗干扰性能。对于采用本地相关检测接收机结构的系统，分析了超宽带系统参数对抗干扰性能的影响，提出了增强超宽带信号抗干扰能力的系统参数选择方法。针对类似差分解调的发送参考系统，研究了在高斯白噪声信道下提高性能的方法；指出传统的发送参考的接收机结构不适合单频干扰存在时的信号解调，提出了改进发送参考系统接收机的结构来提高抗干扰性能的几种方法，包括对延迟相乘的结果进行加权、对参考脉冲进行多符号平均合并等，这些方法在低信噪比和强干扰信号存在的情况下能有效提高系统的抗干扰能力。从理论上给出了基于超宽带冲激无线电方式的常规调制信号的功率谱密度函数的一般性表达式，为超宽带信号的功率谱优化设计提供了理论基础，研究了系统参数对超宽带信号功率谱的影响。并在超宽带信号功率谱的基础上，考察了TD-SCDMA系统在超宽带干扰存在的情况下的带内干扰信号功率，并分析了在超宽带信号存在的情况下直接序列系统解调的误码率，指出了超宽带系统参数对直接序列系统性能的具体影响。更多还原

【Abstract】 Ultra wideband (UWB) radio is a novel wireless communication technology, to which more and more attentions have been paid. UWB wireless communications techniques have many merits, including an extremely simple radio architecture, low-cost design, large processing gain, low power, fine time resolution, which make UWB radio an key role for medium and short range high rate wireless communications in future. And it will have a broad application prospect in wireless communication field.We firstly survey the history and the research status of UWB radar & communications. And the characteristics of the UWB radio signal are analyzed, comparing to some traditional radio. A variety of concentrated problems and fundamental questions are listed. And the main research contents of this thesis are pointed out. Then we introduce the basic modulation schemes of UWB impulse radio and the channel model used for simulation widely.We analyze the BER performance of time-hopping pulse position modulation (TH-PPM) and time-hopping pulse amplitude modulation (TH-BPM) in the deterministic multipath model. And point out that there are unbalanced bit error rate for different transmitted data symbol of UWB TH-PPM while using the conventional receiver architecture, since there is inter-path interference for TH-PPM. Aiming at the unbalanced bit error rate, two solutions are proposed. One is dynamics threshold of RAKE for different channel environment; the other is balance encoding the transmitted data symbol. It is shown by theoretical analysis and computer simulation that these two methods can solve the unbalanced bit error rate of traditional TH-PPM. Comparing with dynamic threshold method, the balance encoding scheme can be implemented more easily, and is more robust to the channel time variant characteristics, the channel estimation of RAKE receiver and the combination techniques.We evaluate the anti-jamming performance of different UWB radio systems. For the modulation scheme with local correlation receiver, we analyze the system parameters impact to anti-jamming performance of UWB system. And we propose the method of system parameters selection to improve the anti-jamming performance. For the differential-demodulation-like TR-UWB system, we investigate the method to improve the performance in AWGN. We analyze that the conventional TR-UWB receiver is not fit for demodulation while single-tone interference is present. And we propose several methods to improve the anti-jamming performance of TR-UWB, including weighting the delay-product result of receiver, averaging multiple reference pulses of TR-UWB received signal. It is shown that the proposed methods can improve the anti-jamming performance efficiently by theoretical analysis and computer simulation.The general closed formula of power spectrum density (PSD) for multi-user aggregate pulsed UWB radio is given, which is the theoretical base for optimizing PSD design of UWB radio. We investigate the main system parameters impact to the PSD of UWB aggregate signals. Based on the proposed PSD of UWB radio, we study the coexistence between the UWB and conventional direct sequence spread spectrum (DSSS). And the in-band interference power of time division-synchronous CDMA (TD SCDMA) is investigated as function of UWB system parameters while the UWB signal and TD SCDMA are overlapped in frequency domain. The BER performance of conventional DSSS system impacted by the UWB radio is analyzed.更多还原