高速UWB-PPM信号传输的并行捕获与检测技术

高速(≥100 Mbit/s)超宽带一脉冲位置调制(UWB-PPM)信号传输是实现超宽带(UWB)室内通信的关键技术.文章结合UWB二元脉冲位置调制(PPM)的信号特征,采用多个并行积分器捕获簇脉冲能量取得快速同步,同时完成PPM的射频同步检测.系统传输试验与系统仿真表明,这种检测方式在室内多径信道下有良好的抗码间干扰能力.     

一种超小型无人机超宽带通信信道模型研究

针对将超宽带无线信号应用于超小型无人机通信链路的低空传输环境,分析了信号传播可能遇到的各种地形、地物等因素对传输损耗的影响,选择修正的S-V多径信道模型,对选定的两个信号传播环境进行了仿真,并给出了信道的路径损耗、冲激响应、rm s时延扩展、平均超量时延、多径分量数目和功率延迟剖面,仿真结果表明该模型能够有效反映信道的特性参数,可为超宽带接收机的设计提供参考。     

基于FPGA的远程USB高速传输系统设计

提出了一种基于现场可编程门阵列（FPGA）的远程高速通用串行总线（USB）传输系统。FPGA作为一种实用的可编程器件,将其应用到USB传输系统中,并配合USB 2.0收发器和光纤传输模块,克服了USB硬件结构对其传输距离的限制,实现了USB远程高速透明传输,使系统传输速度达到480Mb/s,传输距离达10km以上,减少了开发周期,降低了风险。     

UWB通信系统简介

UWB(Ultra Wide Band)即超宽带通信,它使用大于0.5GHz或大于中心频率20%的带宽、通过微弱的脉冲信号进行通信,最大数据传输速率可以达到几十Mb/s～几百Mb/s。UWB与现有的无线技术的显著不同是不需要使用载波,而是通过发送纳秒级脉冲来传输数据,而且信号传输时的功耗只有几十μW。UWB在保证了高数据速率传输的同时解决了移动终端的功耗问题。因此它被认为是对目前被炒得沸沸扬扬的无线互联(Wi-Fi)技术最具竞争性的技术。UWB简介UWB技术多年来一直是美国军方使用的作战技术之一,如它可以实现穿墙视物等功能。这项技术在通信领域所具…     

无线网络UWB即将投入实用房间之间可能采用网格网络

在家庭的家电设备之间收发HDTV动态画面内容,假如要同时传输3～4路MPEG-2方式编码的HDTV流媒体,所需要的有效数据传输速率为70M～100Mb/s,现在的主流无线传输方式WLAN难以满足这一要求.各有关厂家正在大力开发近距离无线技术UWB(超宽带),这种技术可以在WLAN的范围内,利用几GHz的超宽带实现100Mb/s以上的传输速度.     

电波传播

0611748 UWB和PHS之间的电磁干扰分析[刊,中]／赵立昕／／信息安全与通信保密．-2005．(4)．-44-45(L) 超宽带通信系统(UWB)所占用的带宽非常宽,研究超宽带通信系统和其它通信系统间的电磁兼容问题对多通信系统的共存应用具有十分重要的实际意义。本文通过有针对性地选取无线信道传输模型,研究了     

信道时变性对无线激光通信系统的性能影响研究

信道时变性对无线激光通信系统性能具有强干扰影响,因此,提出基于信道时变均衡控制的无线激光通信系统性能优化方法.构建无线激光通信系统的时变信道模型提取信道时变性特征,以此建立无线激光通信系统传输的输出信道衰落特征估计模型进行抗干扰抑制,分析信道时变性对无线激光通信系统相关指标参数的影响,通过Matlab仿真分析进行性能测...     

UWB和PHS之间的电磁干扰分析

超宽带通信系统(UWB)所占用的带宽非常宽,研究超宽带通信系统和其它通信系统间的电磁兼容问题对多通信系统的共存应用具有十分重要的实际意义。本文通过有针对性地选取无线信道传输模型,研究了超宽带通信设备与现存小灵通通信系统间的电磁干扰问题;并根据FCC 和ETSI 所给出的系统参数,给出了此二系统之间的电磁干扰仿真实验结果。     

宽带正交频分复用技术

随着第三代（3G）移动通信系统标准化工作的开展,第四代（4G）移动通信系统的研讨悄然兴起。在业务、功能和频带上,4G都与3G不同。4G数据速率将从2Mb/s提高到100Mb/s,可为全速移动用户提供150Mb/s高质量的影像服务。系统采用直接序列扩频CDMA技术,其射频带宽比数据带宽宽得多,所以该技术主要适用于低速率（kb/s级）和中速率（Mb/s级）业务,对高速及超高速数据传输,无线信道多径时延扩展引起的符号间干扰（ISI）及码片间干扰问题很难解决。正交频分复用（OFDM）技术能进行大容量数据传输,还能解决移动传输高速数据业务引起的…     

超宽带室内信道仿真分析

对超宽带通信室内修正S-V信道模型的进行仿真,在分析S-V信道模型的参数特点的基础上,探讨修正S-V信道模型的数学模型的建立方法,在CM4的非视距(NLOS)信道环境下,用Matlab进行仿真实验,结果表明修正S-V信道模型更接近实际,比S-V信道模型具有更好的信道冲激响应特性,能够更好地应用于超宽带通信系统性能的信道传输特性研究。     

A Novel Multimedia Streaming Scheme for N-Screen Services in Wireless USB Networks

Ultra wideband (UWB) technology has emerged as a solution for the wireless interface between medical sensors and a personal server in future telemedicine systems. Wireless universal serial bus (USB) is the USB technology merged with UWB technology. Wireless USB can be applied to wireless personal area network applications as well as personal area network applications like wired USB. In case of n-screen service applications, data traffics must broadcast to the adjacent devices However, the current wireless USB is designed to support the communication through the point-to-point connection between the host and the device only. This policy increases delay and energy consumption of wireless host and devices significantly. Therefore, in this paper, we propose a novel multimedia streaming scheme for n-screen service in wireless USB networks. The simulation results show that proposed protocol can enhance the throughput and delay performance and improve energy efficiency by minimizing the multimedia data delivery process.     

Noise immunity of the wireless communications scheme based on ultrawideband chaotic radio pulses in multipath channels

The problem of determining the noise immunity of wireless data transmission based on ultrawide-band (UWB) chaotic radio pulses in the multipath channel with white noise is substantiated. The results have been calculated via numerical simulation using the multipath channel models describing UWB signal propagation in rooms of different classes at distances as long as several tens of meters. The direct chaotic communications method is shown to have the noise immunity high enough to employ this scheme in practical wireless applications where information is transmitted under severe conditions of multipath propagation. In this case, the ultimate data transfer rates are found to 25 Mb/s.     

The ultra wideband WiMedia standard [Standards in a Nutshell]

WiMedia is a radio platform standard that enables shortrange, high-speed wireless connectivity using ultra wideband (UWB) multiband orthogonal frequency division multiplexing (MB-OFDM) technology. It currently enables rates of up to 480 Mb/s in the physical layer and provides an architecture that supports multiple applications via various protocol adaptation layers. As a result, the WiMedia standard has been adopted by the USB Implementers Forum as the Wireless Universal Serial Bus (WUSB) standard and by the Bluetooth Special Interest Group for the next generation Bluetooth 3.0 standard for next generation consumer electronic applications. WiMedia also defines an adaptation layer to use WiMedia for Wireless Internet protocol (IP) known as WiMedia Network and is being considered in other applications such as IEEE 1394 (Wireless Firewire). This article briefly describes the WiMedia standard-the architecture, the technologies deployed in the standard, the applications enabled by it- and compares WiMedia to existing wireless local area network (WLAN) and wireless personal area network (WPAN) standards.     

Performance Analysis of UWB Channels for Wireless Personal Area Networks

Ultra-wide band (UWB) communication is one of the most promising technology for high data rate networks over short-range communication. The ultra-wide bandwidth offers pulses with very short duration that provides frequency diversity and multipath resolution. Ultra-wide band (UWB) channels raise new effects in the receiver, the amplitude fading statistics being different compared to the conventional narrow band wireless channels. This review paper focuses on modeling of ultra-wide band channels, especially for simulation of personal area networks and also discusses the benefits, application potential and technical challenges in wideband communication. The concept of Orthogonal Frequency Division Multiplexing (OFDM) has recently been applied in wireless communication systems due to its high data rate transmission capability with high bandwidth efficiency and its robustness to multi-path delay. UWB OFDM communication was proposed for physical layer in the IEEE 802.15.3a standard which covers wideband communication in wireless personal area networks. Since the channel model for multicarrier UWB communication is different from that of plain ultra-wide band channel, a novel modification method in UWB channel model is proposed with specific center frequency and multipath resolution. Moreover, dynamic channel estimation is necessary before demodulation of UWB OFDM signals since the radio channel is time varying and frequency selective for wideband systems. The performance of the proposed method is statistically analyzed using LS and MMSE based channel estimation methods.     

Investigation and Modeling of the UWB On-Body Propagation Channel

Wireless Body Area Networks (WBANs) are becoming an increasingly important part of the wireless communication system. In such a communication system various electronic devices carried by a person on his body can be connected. In this paper, we investigate the UWB body area propagation channel. The channel characterization is based on UWB on-body channel measurements. This paper describes the measurement campaign and the basic characteristics of the body area propagation channel extracted from measurement data.     

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     

Interference Mitigation in Wireless Body Area Networks Using Modified and Modulated MHP

Wireless Body Area Networks (WBAN) is an emerging area in field of remote health monitoring and telemedicine. UWB is a preferred candidate for the WBAN as it provides very high data rate at minimal cost and power consumption. Since the UWB-WBAN is wireless, it will be affected by interference from existing wireless personal and local area networks. Interference immunity is a major issue in wireless Body Area Networks as patients’ vital data containing details of functioning of vital organs and blood flow are carried. The paper investigates the performance of modified and modulated hermite pulses (MHP) for narrowband interference mitigation in the 4,940–4,990 MHz band IEEE 802.11y Public Safety band interference. This 50 MHz interfering band will be a critical interferer due to the higher power levels of interfering system. Performance of the proposed technique have been shown in comparison with Gaussian pulse shapes and has been further validated by transmitting ECG and MRI data by it in presence of strong interference.     

基于ZigBee无线热能检测系统设计

为了能无线监测用户热能使用量,设计一种ZigBee传感器网络系统,终端节点将传感器采集的数据遵循ZigBee无线通信协议发送到协调器,协调器通过USB转串口把数据上传到PC机,最后由上位机计算并显示数据。该系统可以对用户热能使用数据进行无线实时监测。试验结果表明,节点监测数据稳定性好,组网灵活,功耗低,具有较高实用价值。     

Low-Power Impulse UWB Architectures and Circuits

Ultra-wide-band (UWB) communication has a variety of applications ranging from wireless USB to radio-frequency (RF) identification tags. For many of these applications, energy is critical due to the fact that the radios are situated on battery-operated or even batteryless devices. Two custom low-power impulse UWB systems are presented in this paper that address high- and low-data-rate applications. Both systems utilize energy-efficient architectures and circuits. The high-rate system leverages parallelism to enable the use of energy-efficient architectures and aggressive voltage scaling down to 0.4 V while maintaining a rate of 100 Mb/s. The low-rate system has an all digital transmitter architecture, 0.65 and 0.5 V radio-frequency (RF) and analog circuits in the receiver, and no RF local oscillators, allowing the chipset to power on in 2 ns for highly duty-cycled operation.      

UWB技术在有线电视网中的应用

起宽带(Ultra Wideband，UWB)技术是近几年发展起来的一项十分有潜力的无线通信技术，以其高性能、低成本的无线数据通信能力，成为实现无线个人局域网的富有竞争力的技术之一。依据起宽带技术的主要特点，讨论了该技术在有线电视网中应用的优势及其实现，这不仅为解决有线电视网带宽“瓶颈”问题提供了有效的方案，也使UWB技术得到了更广泛的应用。