混沌脉位调制UWB系统及信号分析

针对高通信速率下跳时脉位调制(TH-PPM)的超宽带(UWB)系统多址能力有限、信号离散功率谱分量高的缺点,引入了基于TENT映射的混沌脉位调制(CPPM)UWB系统,得到了其信号的功率谱密度表达式.分析和仿真表明高速UWB系统CPPM比TH-PPM的信号具有更强的多址能力和更平滑的连续功率谱分量,而且离散谱分量比TH-PPM方式低三个数量级.从而能减少对其它通信系统的干扰、具有更低截获概率和高保密性.     

超宽带分组无线Ad Hoc网络性能分析

超宽带技术被看作当前无线通信技术中最有前途的技术.本文根据UWB通信的多址方式,提出一种室内短距离分组移动自组网(ad hoc)的模型,然后讨论了UWB信号物理层与窄带信号不同的同步捕获问题和多址干扰问题,利用马尔可夫链分析了这种应用于UWB Ad Hoc无线局域网的时隙ALOHA-CDMA随机接入协议.结果表明,UWB的脉冲重复周期(To)与脉冲宽度(Tp)之比对性能的影响很大,只要设计合理,UWB信号在移动自组网就中可以充分发挥其优势,突破频谱瓶颈.     

UWB无线通信关键技术与应用

对UWB无线通信的关键技术进行了分析和研究,包括标准、脉冲信号、调制及多址方式、信道特点,并介绍了与UWB有关的重要应用,展望了UWB的发展前景.     

多用户检测在超宽带无线通信中的应用

在超宽带(UWB)通信系统中多址干扰是限制系统性能的重要原因,为了有效抑制多址干扰,本文将多用户检测技术应用于超宽带多用户通信系统中。通过分析信号特征,给出了应用在UWB系统中的几种次最佳多用户检测器的结构,考虑到实际UWB系统需要接收机有较低的复杂度,又提出了一种特别针对UWB系统的类最小均方差(MMSE)检测器并分析了其性能。在UWB室内信道环境下的仿真表明,采用本文提出的多用户检测器可以取得明显优于传统接收机的系统性能。     

跳时序列对UWB系统多址性能的影响

通过变换超宽带(UWB)无线电通信系统的信号模型,分析了该通信系统的多址性能,给出了跳时序列与其所产生的多址干扰之间的关系,从而明确了跳时序列的相关性能对该通信系统误码率的影响。     

超宽带通信的调制及其信号特征

首先分析了超宽带(UWB)通信的传输载体及其具有的特征，并从传输载体的时间与幅度参数变更出发来表述几种常用的UWB多址调制与数据调制方式及其信号特征。最后从低功率谱的平坦性、密集多径环境下性能等方面对各种调制作了适当的评述。     

一种结构简单UWB接收机的设计与实现

本文通过同步提取UWB积分信号的方式,在信号到来时,信号积分的能量进入后面的比较判决电路,实现信号的检测,没有信号时,屏蔽外来的信号和干扰。此方法提高了接收信号的信噪比,系统实现相对简单,同时实现了多址通信。     

超宽带技术及其在CATV中的应用

介绍超宽带(UWB)无线通信技术的概念及其基本工作原理,包括信号特性、多址方式、收发机结构及UWB无线标准等,并介绍UWB应用于宽带同轴电缆,特别是CATV/HFCS中的技术.     

超宽带技术及其在CATV中的应用

介绍超宽带(UWB)无线通信技术的概念及其基本工作原理,包括信号特性、多址方式、收发机结构及UWB无线标准等,并介绍UWB应用于宽带同轴电缆,特别是CATV/HFCS中的技术.     

超宽带技术及其在CATV中的应用

介绍超宽带 (UWB)无线通信技术的概念及其基本工作原理 ,包括信号特性、多址方式、收发机结构及UWB无线标准等 ,并介绍UWB应用于宽带同轴电缆 ,特别是CATV/HFCS中的技术     

An Analysis of Interference Mitigation Capability of Low Duty-Cycle UWB Communications in the Presence of Wideband OFDM System

Low duty-cycle (LDC) algorithm is interference mitigation technique, which can reduce the average interference to the existing radio systems by lowering pulse repetition interval or pulse occupation time. In this paper, the coexistence environment between low data rate ultra wideband (UWB) communication system such as wireless sensor network and the existing wideband system using orthogonal frequency division multiplexing (OFDM) such as 4th generation mobile cellular system (4G), worldwide interoperability for microwave access (WiMAX), and field pickup unit (FPU) is considered. In order to analyze the interference mitigation capability of LDC algorithm with impulse based UWB (LDC-UWB) system, the frame error rate (FER) of wideband OFDM system is examined for two types of LDC-UWB system: the signal with random polarity such as binary pole signals and without random polarity such as mono pole signals. We present that LDC algorithm is an efficient interference mitigation technique for low data rate UWB communication via computer simulations regardless of definitions of transmitted energy of UWB communication system, and also that the signal with random polarity is suitable for LDC-UWB system to mitigate interference to the other radio systems. We further investigate the adequate duty-cycle of LDC-UWB system for each definition of transmitted power of UWB communication.     

多带OFDM超宽带系统信道估计的研究

超宽带(UWB)以其隐蔽性好、传输速率高,抗多径和窄带干扰能力强等优点,在短距多址无线通信中良好的应用前景而引起广泛研究.以多带OFDM超宽带通信系统为背景,主要研究UWB系统室内密集多径信道的估计,提出两种基于训练比特的UWB信道估计算法--ML算法和IML算法.仿真结果表明:两种信道估计算法都能够有效估计信道参数,而IML算法在消除多径成分之间相互干扰方面更优越.     

Performance analysis of 3G systems in presence of UWB interference

In this paper,the impact of the interference from multiple ultra wideband(UWB) transmitters to a 3rd-generation(3G) terminal is evaluated under UWB emission power limit regulations of federal communications commission(FCC),european telecommunications standards institute(ETSI) and Japan respectively.A three-dimensional interference model is presented where a discrete spatial distribution of UWB transmitters is considered.It is assumed that a mobile terminal and a large number of UWB devices exist in one room simultaneously.A parameter which characterizes the link budget degradation at the victim receiver is defined to measure the UWB interference to 3G systems.The maximum acceptable density of UWB transmitters and the minimum acceptable distance between UWB transmitters and the 3G terminal are analyzed under different link budget degradations.The simulation results demonstrate that the performance of time division-synchronous code division multiple access(TD-SCDMA) is the best,the one of code division multiple access 2000(CDMA2000) is the worst and the one of wideband code division multiple access(WCDMA) lies between them in presence of UWB interference.     

脉冲超宽带TH-PPM多址通信的误比特率计算方法

简单地给出了脉冲超宽带(IR-UWB)TH-PPM多址通信方式在信道加性白高斯噪声(AWGN)与多址用户干扰高斯近似条件下的误比特率推导过程。从接收端相关检测时多址用户信号与本地模板信号相互作用产生误相关输出的平均出发,假定多址用户干扰是零均值的高斯过程,分析计算多用户干扰的方差,通过数值计算与系统仿真比较了所得到的结果。     

Multiple access interference and multipath interference analysis of orthogonal complementary code‐based ultra‐wideband systems over multipath channels

In order to alleviate multiple access interference and multipath interference of ultra‐wideband (UWB) system, we propose the orthogonal complementary code (OCC)‐based direct‐sequence UWB system and offset‐stacking (OS)‐UWB system. OCC has perfect partial autocorrelation and cross‐correlation characteristics. With the application of OCC in UWB system, we can obtain better performance in multiple access interference and multipath interference. The proposed OS‐UWB structure can also achieve variable data rate transmission because of its innovative OS spreading technique. Theoretical analysis and simulation results show that the proposed UWB system can achieve excellent performance and outperform the unitary code‐based direct‐sequence UWB system. Copyright © 2013 John Wiley & Sons, Ltd.     

Ultra‐wideband multiple‐access relay channel with correlated noises and its diversity analysis

In this study, we investigate a new and practical model, ultra‐wideband Slepian–Wolf multiple‐access relay channel (UWB‐SW‐MARC) with correlated noises at the relay and receiver, which includes two important models, that is, UWB‐SW multiple‐access channel with correlated noises and UWB relay channel with correlated noises, as its special cases. We derive a general rate region for UWB‐SW‐MARC and obtain an outer bound for this model and, thereby, prove two certain capacity theorems for two important and different classes of MARC. Also, we analyze outage probability and diversity gain as the practically important concepts in wireless communications and prove that adding a relay to the multiple‐access channel improves the diversity gain. Finally, we evaluate some results numerically and illustrate that the noise correlation coefficient plays an important role in determining the relay position, and show that the channel performance depends on the noise variances. Copyright © 2014 John Wiley & Sons, Ltd.     

Multiple Access <Emphasis Type="Italic">M</Emphasis>-ary Modulation UWB System Based on Code-Selected Direct Sequence Bipolar PAM

This work presents an M-ary multiple access code-selected direct sequence (DS) ultra wideband (UWB) communication system. A high data rate multiple access UWB system can be obtained by a code selection mechanism. In the proposed system, each user is assigned a DS code set with M/2 DS code sequence and a particular DS code sequence can be selected by the log₂ (M/2) bits from the DS code set. More importantly for this M-ary UWB communication system, with the increase of the modulation level M, it allows to reduce the required transmitter power maintaining the number of users, the data transmission rate and the multiple access performance. In this paper, we also introduce the detailed algorithm to compute the bit error rate (BER) over the AWGN channel and correlation receivers.

超宽带脉冲信号设计

超宽带无线通信技术是利用极窄脉冲传输的系统,其中脉冲波形是其研究中的重要内容。主要讨论了正弦调制高斯脉冲和Meyer小波脉冲,通过MATLAB仿真分析研究,发现它们与高斯脉冲相比,具有一些优点,可以满足某些特定的要求,能够改善超宽带无线通信系统的性能。     

正交Hermite脉冲的超宽带的多用户通信

正交Hermite脉冲被提出用于超宽带无线通信。该文提出新方法用于超宽带通信的多用户传输系统。通过同时传输多个正交Hermie脉冲,超宽带多用户传输系统可以获得好的性能特征。该文还提出了正交Hermite脉冲应用于UWB的DS-CDMA系统以同时支持更多的用户通信。     

用于个人局域网的超宽带技术研究

近年来 ,随着各种短距离无线通信技术的发展 ,学术界提出了新的概念 :个人局域网 (PersonalAreaNet work ,PAN)。首先简要介绍了超宽带 (UltraWideband)概况 ,然后着重分析介绍了用于无线个人局域网的超宽带技术 ,分析结果表明 ,超宽带通信是一项很有发展潜力的高速无线接入技术。