提高超宽带冲激无线电信号抗单频干扰能力的参数选择方法

针对三种超宽带冲激无线电信号(TH-PPM、TH-PAM和DS-UWB)在强单频干扰下的存在误码率恶化的情况,通过理论分析和计算机仿真验证,分析了影响超宽带冲激无线信号抗单频干扰能力的主要系统参数,提出了提高三种超宽带无线电信号抗单频干扰能力的系统参数选择方法。采用这种参数选择方法,可主动降低甚至消除干扰信号对超宽带冲激无线电信号的干扰,降低超宽带冲激无线电接收机设计的复杂性。     

超宽带通信技术抗部分频带干扰性能研究

抗干扰能力是超宽带通信技术必须研究的关键问题之一.建立了部分频带干扰模型和超宽带通信系统模型,并忽略背景热噪声的影响.通过理论分析和实验仿真,分析了脉冲参数和跳时码参数与超宽带通信系统抗干扰性能之间的关系.最后,通过分析比较得出了一些有益的结论,为脉冲无线电技术在未来的实际应用提供了有价值的参考.     

超宽带技术在认知无线电中的应用研究

分析了超宽带技术应用于认知无线电的可行性,阐明了基于超宽带技术的认知无线电所面临的主要问题,并从无线环境感知与发现策略、环境感知型无线信号的生成、干扰信号处理和共存、感知网络及实验平台等关键技术方面探讨了超宽带技术在认知无线电的应用前景.     

基于认知超宽带的频谱共享技术研究

引入了认知无线电思想构成认知超宽带(CUWB),达到抑制窄带的通信目的.分析了高斯导函数组合脉冲波形叠加的方式以及脉冲形成因子的寻找算法,并且结合认知无线电频谱检测技术在干扰频点降低超宽带(UWB)能量.仿真结果证明了引入认知能够提高未受干扰频段功率,增大UWB通信距离,并改善与其他无线系统频谱共享.     

UWB脉冲的特征分析

介绍了超宽带脉冲无线电对脉冲波形的要求及FCC对UWB的频谱规划。详细分析了影响UWB脉冲波形及其谱形状的因素,分别给出了Rayleigh脉冲在不同脉冲形状参数α与不同求导阶数n时的时域波形及其频谱密度PSD,并研究了α与n对峰值频率及带宽的影响。分析结果表明,可通过仔细选择α与n来设计满足FCC频谱规划的脉冲,这对超宽带脉冲无线电中波形的选择具有指导性意义。     

超宽带无线电抗干扰性能分析

随着科技水平的提升,人们的生活质量也得到了很大的提高,超宽带无线电技术被广泛的应用于人们的生产、生活中,为人们带来了极大的便利.超宽带无线电技术属于通信技术的范围,它具有一定的先进性、抗干扰性,在广播领域中得到了极大的关注.本文主要对超宽带无线电技术进行介绍,进而分析超宽带无线电技术的关键技术,并对超宽带无线电技术的抗干扰性能进行分析,从而促进超宽带无线电技术的发展与应用.     

UWB信号抗窄带干扰一种新方法的研究

超宽带通信以低占空比的超短冲激脉冲作为载体,无需载波调制,采用伪随机直扩或跳时技术实现信息传输。然而,超宽带信号常常被隐蔽在环境噪声和其他干扰中,难以检测。因此,研究超宽带无线电信号抗窄带干扰技术,具有重要的意义。本文概述了超宽带无线通信,分析了超宽带的信号特点,介绍了传统的窄带干扰抑制方法,研究了一种新的基于局域波分析方法一一希尔伯特黄变换的信号抗窄带干扰法.仿真结果表明该方法能够有效地从单音干扰和线性调频干扰中恢复出超宽带信号。     

一种新颖的超宽带无线电跳时序列设计

分析跳时序列在跳时脉冲位置调制(TH-PPM)超宽带无线电系统中的作用及对系统性能的影响。给出了一种新颖的跳时序列设计方法,理论分析该跳时序列具有最佳的汉明相关特性,适用于跳时超宽带多址系统。计算机仿真验证了在超宽带无线电多址系统中,采用该跳时序列比其他跳时序列更能有效地抑制多用户干扰的影响,从而获得较佳性能。     

超宽带(UWB)技术及其抗干扰性能分析

介绍了跳时超宽带(TM-UWB)通信的特点,通过对比传统的RAKE接收机和MMSE-RAKE接收机性能分析了UWB的抗窄带干扰性能,结果表明超宽带在无线个人域网中(WPAN)可以和其它无线电系统共存.     

认知无线电在UWB中的应用

认知无线电与超宽带技术都是近年来新兴的无线通信技术,文章介绍了认知无线电的技术特点,对认知无线电在超宽带技术中的应用可行性进行了分析,并提出了将二者结合的脉冲信号的产生方法和功率控制方法,对认知无线电在超宽带网络中的应用具有重要的实践意义.     

基于认知无线电的脉冲陷波UWB窄带干扰抑制

提出了一种基于认知无线电的自适应超宽带(UWB)窄带干扰抑制方法.为了使UWB对变化的干扰环境具有自适应调节能力,引入了认知无线电技术.通过频谱感知和认知引擎技术提取窄带干扰频谱特征作为陷波器的设计依据.以高斯脉冲为例,对陷波器的陷波性能进行检验.最后,就陷波前、后脉冲的通信性能进行比较.仿真结果表明:认知陷波脉冲具有...     

Application of convolutional error correcting codes in ultrawideband M-ary PPM signaling

The interference issues related to ultrawideband (UWB) radio pose tight restrictions on the maximum data rate of UWB radio telecommunication systems. A possible solution is to reduce the required signal to interference ratio (SIR) that gives satisfactory performance to the UWB system. In this letter, we propose coded M-ary UWB radio communication systems. Two classes of convolutional codes, namely, low-rate superorthogonal codes and high-rate punctured codes are considered for this purpose. Simulation results on the bit error rate of the proposed system indicates that the system is capable to work in lower SIR's and therefore supports higher data transmission rates in a real interference environment compared to the previously proposed UWB communication systems.     

On the UWB system coexistence with GSM900, UMTS/WCDMA, and GPS

This paper evaluates the level of interference caused by different ultra-wideband (UWB) signals to other various radio systems, as well as the performance degradation of UWB systems in the presence of narrowband interference and pulsed jamming. The in-band interference caused by a selection of UWB signals is calculated at GSM900, UMTS/wideband code-division multiple-access (WCDMA), and Global Position System (GPS) frequency bands as a function of the UWB pulsewidth. Several short-pulse waveforms, based on the Gaussian pulse, can be used to generate UWB transmission. The two UWB system concepts studied here are time hopping and direct sequence spread spectrum. Baseband binary pulse amplitude modulation is used as the data modulation scheme. Proper selection of pulse waveform and pulsewidth allows one to avoid some rejected frequency bands up to a certain limit. However, the pulse shape is also intertwined with the data rate demands. If short-pulses are used in UWB communication the high-pass filtered waveforms are preferred according to the results. The use of long pulses, however, favors the generic Gaussian waveform instead. An UWB system suffers most from narrowband systems if the narrowband interference and the nominal center frequency of the UWB signal overlap. This is proved by bit-error rate simulations in an additive white Gaussian noise (AWGN) channel with interference at global system for mobile communication (GSM) and UMTS/WCDMA frequencies.     

Performance evaluation of non‐Gaussian channel estimation techniques on ultrawideband impulse radio channels

We study the problem of adaptive channel estimation for a multipath channel on an ultrawideband (UWB) impulse radio (IR) system. The purpose of the work is to demonstrate that the statistical characteristics of the UWB‐IR environment are strongly non‐Gaussian and that as a result, non‐Gaussian signal processing techniques are both efficient and powerful in a UWB‐IR environment. The multipath channel estimation problem has been chosen as an illustrative example because UWB‐IR systems often operate in complex multipath environments. We study both blind and training‐based estimation techniques and demonstrate that even simple non‐Gaussian strategies can achieve significant performance improvement when compared to more common second‐order estimation techniques. Copyright © 2006 John Wiley & Sons, Ltd.     

Ultra-Wideband Radio Signals Distribution in FTTH Networks

The use of an ultra-wideband (UWB) radio technique is proposed as a viable solution for the distribution of high-definition audio/video content in fiber-to-the-home (FTTH) networks. The approach suitability is demonstrated by the transmission of standards-based UWB signals at 1.25 Gb/s along different FTTH fiber links with 25 km up to 60 km of standard single-mode fiber length in a laboratory experiment. Experimental results suggest that orthogonal frequency-division-multiplexed UWB signals exhibit better transmission performance in FFTH networks than impulse radio UWB signals.     

ATM-based TH-SSMA network for multimedia PCS

Personal communications services (PCS) promise to provide a variety of information exchanges among users with any type of mobility, at any time, in any place, through any available device. To achieve this ambitious goal, two of the major challenges in the system design are: (i) to provide a high-speed wireless subsystem with large capacity and acceptable quality-of-service (QoS) and (ii) to design a network architecture capable of supporting multimedia traffic and various kinds of user mobility. A time-hopping spread-spectrum wireless communication system called ultra-wide bandwidth (UWB) radio is used to provide communications that are low power, high data rate, fade resistant, and relatively shadow free in a dense multipath environment. Receiver-signal processing of UWB radio is described, and performance of such communications systems, in terms of multiple-access capability, is estimated under ideal multiple-access channel conditions. A UWB-signal propagation experiment is performed using the bandwidth in excess of 1 GHz in a typical modern office building in order to characterize the UWB-signal propagation channel. The experimental results demonstrate the feasibility of the UWB radio and its robustness in a dense multipath environment. A ATM network is used as the backbone network due to its high bandwidth, fast switching capability, flexibility, and well-developed infrastructure. To minimize the impact caused by user mobility on the system performance, a hierarchical network-control architecture is postulated. A wireless virtual circuit (WVC) concept is proposed to improve the transmission efficiency and simplify the network control in the wireless subsystem. The key advantage of this network architecture and WVC concept is that the handoff can be done locally most of the time, due to the localized behavior of PCS users     

脉冲电磁波传输过程中的失真分析

超宽带通信是近几年发展起来的短距离无线通信技术,而无线通信信道特征取决于信号传播的电磁环境。运用频域法研究大地媒质中的脉冲传播和辐射问题,且在此基础上分析脉冲电磁波穿过3层媒质的失真情况,并分析现代建筑物中的混凝土砖墙对信号传播的影响。通过仿真得到超宽带脉冲信号在传输过程中的失真结果,这对遥感及超宽带通信系统的设计意义重大。     

基于IEEE 1394和UWB的家庭网络

基于IEEE 1394和UWB技术的家庭网络能连接众多电子娱乐设备,形成无缝隙的家庭无线环境,提供互操作功能和多媒体业务.本文首先简要介绍了IEEE 1394和UWB的特点,然后分析了基于IEEE 1394和UWB的家庭网络的一些具体问题,如网络结构、兼容设备的协议栈、UWB总线的物理层和数据链路层的特点等.     

脉冲波形对超宽带通信系统性能的影响

超宽带（UWB）技术的特点是传输持续时间极窄的脉冲，纳秒级窄脉冲（称为monocycle）的选择将直接影响到UWB通信系统的性能。本文研究了一种新的基于小波函数的超宽带窄脉冲，并比较其和传统的超宽带窄脉冲在AWGN信道中采用直接序列扩频（DS）的UWB系统性能。仿真结果表明了基于小波函数脉冲波形的UWB系统性能优于基于传统超宽带窄脉冲的UWB系统。