高速通信中的载波相位跟踪

为了解决扩频通信体制的通信速率相对较低而无法满足高速高清图像的无线传输通信需要的问题,文中对实现高速基带解调的一项关键技术,也就是载波相位跟踪技术进行了研究。     

Interference impacts on 60 ghz real-time online video streaming in wireless smart tv platforms

In this paper we provide a method for computing and estimating the impact of interference on real-time online 1080p@30Hz and 1080p@60Hz high-definition video streaming in 60 GHz wireless smart TV platforms. The analysis involves two different interference scenarios: 1) downlink interference from deployed 60 GHz access points to the associated mobile ad-hoc devices, and 2) uplink interference from randomly deployed 60 GHz ad-hoc mobile devices to their associated access points. With these interference scenarios, the interference impact on the quality of main 1080p@30Hz and 1080p@60Hz wireless high-definition video streaming with various simulation settings are measured and estimated in terms of signal-to-interference-plus-noise ratio.     

Wireless transmission of HD video using H.264 compression over UWB channel

With the technological advancement, entertainment has become revolutionized and the high-definition (HD) video has become an integral feature of our modern amusement system. The demand for wireless transmission of HD video is rapidly rising for its ubiquitous nature, easy installation and relocation. Such wireless transmissions of HD video streams require very high bandwidth. The ultra-wideband (UWB) offers a large bandwidth, and short-range high-speed data transmission at low cost and low power consumption. In this paper, we present the feasibility study to transmit HD video wirelessly using H.264/AVC compression over the UWB communication channel. Simulations are carried out by controlling key H.264/AVC encoder parameters such as, in-loop deblocking filter, group of pictures, and quantization parameter. Based on the analysis, an optimum setting of these parameters is proposed for different bandwidth requirements, as well as acceptable video quality. The bandwidth achieved is restricted between 1.5 and 20?Mbps with a minimum reconstruction quality of 34?dB. The HD bit stream is then transmitted over the UWB communication channel and the demonstration shows that the overall encoder performance is satisfactory with the transmission bit-error-rate (BER) in the range of 10^?5?C10^?8.     

基于能量最优的通信安全频域均衡方法仿真

无线通信不可避免的会受到传输环境的影响,使其受到较为严重的码间干扰,导致频域失衡。目前的频域均衡控制方法虽然可以一定程度地抑制码间干扰,但并未考虑无线通信能量资源,导致能量资源的利用率较低,通信网络寿命较低。为此提出一种基于能量最优的通信安全频域均衡方法。首先分析频域均衡原理,将发射数据中最后一帧拷贝到帧头,以此作为循环的前缀通过并串变换传送至接收端,清除循环前缀,获得重建后数据信号中的MMSE(最小均方误差)均衡与迫零均衡,其次使用SC-FDE(单载波频域均衡)系统清除信号间隔来保护码间串扰,并利用最小均方误差减少信道深衰落完成基于能量最优的均衡补偿。仿真得出,所提方法能够有效保证信道安全性,拥有较好的频域均衡效果,相比其它方法更节省能量,延长通信网络的寿命。     

矿井宽带无线传输技术研究

提出了矿井宽带无线传输技术是解决采掘工作面移动监控、监视和语音通信需求的关键技术。提出了矿井宽带无线传输应满足传输带宽宽、便于接入有线宽带网络、中继设备少、体积小、发射功率小、电磁兼容性好、安全性好、传输协议标准化、电源电压波动适应能力强等要求。提出了漏泄通信不能用作矿井宽带无线传输技术,但可用于煤矿井下局部通信等;感应通信不能用作矿井宽带无线传输技术,但可用于煤矿井下救灾通信等;透地通信不能用作矿井宽带无线传输技术,但可用于煤矿井下避难硐室等应急通信;小灵通、CDMA、GSM、Bluetooth不能用作矿井宽带无线传输技术;RFID不能用作矿井宽带无线传输技术,但可用于煤矿物联网、矿用设备管理和防碰撞等;ZigBee不能用作矿井宽带无线传输技术,但可用于煤矿井下人员、胶轮车、电机车等动目标精确定位和矿用传感器无线传输等;UWB不能用作矿井宽带无线传输技术,但可用于煤矿井下生命探测、防碰撞、煤矿井下人员和胶轮车等动目标精确定位等;WCDMA、CDMA2000、TD-SCDMA等3G不能用作矿井宽带无线传输技术,但可用于煤矿井下语音移动通信等。提出了矿井宽带无线传输技术宜采用WiFi,4G有可能成为未来矿井宽带无线传输技术。     

基于ARM11的嵌入式无线视频终端的设计

随着无线局域网的广泛应用,为了在嵌入式系统中整合无线局域网宽带通信技术进行视频传输;提出一种基于ARM11硬件平台和嵌入式Linux操作系统的无线视频终端系统的设计方案,给出系统的总体设计和主要功能模块的实现,其中包括视频采集模块、无线视频传输模块的硬件设计,嵌入式Linux的驱动程序移植、H.264数字视频压缩及应用程序实现等;该系统实现了802.11无线局域网内的视频传输,实时监测网络的数据流量和拥塞状况,提高网络传输质量,保证视频播放流畅性,可靠性高且易于使用;实践证明本系统稳定性高,实时性好,运行可靠,可应用于视频监控领域。     

Performance analysis of DFT spread generalized multi-carrier systems

Discrete Fourier transform-spread generalized multi-carrier (DFT-S-GMC) based single carrier-frequency division multiple access (SC-FDMA) scheme is a promising solution for uplink transmission of broadband wireless communication. In this paper, the impact of non-perfect orthogonal prototype filter to the performance of the DFT-S-GMC system is discussed. Single sub-band frequency-domain equalization (FDE) method is presented and the performance loss caused by FDE-tone discarding is analyzed. Moreover, the post-processing signal to interference plus noise ratio (SINR) of DFT-S-GMC receiver over multi-path channel is addressed. The theoretical analysis illustrates that the non-perfect orthogonal prototype filter results in inter-symbol interference (ISI) and inter-sub-band interference (IBI), and the variance of the ISI is still less than 1e−4 and much larger than that of IBI. By designing proper system parameters, the reconstruction error due to FDE-tones discarding can be controlled under −40 dB; the post-processing SINR of the DFT-S-GMC receiver with minimum mean square error (MMSE) equalization is higher than that with zero forcing (ZF) equalization. The theoretical performances are verified by extensive simulation results.     

基于归零基带脉冲的OOK/DAMI方案

针对传统60 GHz毫米波无线通信系统的不足,提出了一种新型的基于归零基带脉冲OOK/DAMI方案。介绍了基于归零基带脉冲OOK/DAMI体制的60 GHz毫米波通信系统的发送端模型,简单分析了各个模块的功能,给出了通信系统接收端模型并进行了简要说明,描述了3种常用的ps级脉冲信号的产生方法与各自的优缺点。仿真分析了不同类型脉冲信号的功率谱密度,最后给出了合成基带脉冲的时域调制波形图和对应的功率谱密度图,仿真显示能够满足60 GHz通信中功率谱遮蔽特性的要求。     

矿用5G频段选择及天线优化设置研究

矿井无线通信和矿用5G移动通信技术是煤矿智能化关键技术之一。为提高煤矿井下无线传输距离、绕射能力及无线通信系统的稳定性和可靠性,减少基站用量、组网成本和维护工作量,研究了矿用5G工作频段和基站天线位置对无线传输损耗和传输距离的影响。主要结论如下:①煤矿井下无线发射功率受本质安全防爆限制,接收灵敏度受电磁噪声限制,天线增益受本质安全防爆和巷道空间限制。在煤矿井下无线发射功率、接收灵敏度、天线增益受限的情况下,应通过优选无线工作频段和优化天线设置位置,提高矿井无线传输距离和绕射能力,提高系统稳定性和可靠性,减少基站用量、组网成本和维护工作量。②矿用5G工作频段应优选700 MHz。煤矿井下700 MHz频段与现有5G其他工作频段2.6,3.5,4.9 GHz相比,具有无线传输损耗小、无线传输距离远、绕射能力强、基站用量少、组网成本低和维护工作量小等优点。③提出的传输损耗/位置变化率分析方法便于分析巷道横向不同区域位置变化引起的无线传输损耗变化情况。④无线基站天线应靠近巷帮设置,距巷帮不小于0.01 m,垂向位于巷道高度约2/5处。这样既不影响行人和行车、便于安装维护,也可以满足无线传输损耗较小、无线传输距离较远的要求。⑤矿用手机、人员定位卡、便携式无线甲烷检测报警仪、多功能无线矿灯、便携式无线摄像机、便携式无线仪器设备、可穿戴无线设备、车辆定位卡、车载无线设备、无线摄像机、无线传感器、物联网设备等无线终端,在不影响使用的条件下应尽量靠近巷道中心,以提高无线传输距离。     

基于CPRI协议的FPGA高速数据传输模块设计与实现

随着通信技术不断发展,CPRI协议作为无线基站的接口规范逐步完善,可支持的数据速率不断提高。本课题基于“新一代宽带无线通信网”国家科技重大专项：TD-LTE基站基带与射频模块间接口（Ir接口）仿真与监测工具开发。本文为了测试基带设备对IQ数据的处理能力,基于FPGA实现对用户数据（IQ数据）的实时高速传输至上位机进行存储。通过比较现有高速数据传输技术,提出采用分层化,模块化的设计思想,利用FPGA实现UDP/IP协议栈,通过千兆以太网传输至上位机。通过测试验证,本模块可实现对IQ数据的实时高速传输,满足设计要求。     

采煤机音视频及数据综合传输系统的设计

针对现有采煤机视频、音频及工况监控数据实时传输系统采用无线局域网、光缆或单独拖曳通信电缆时存在不稳定、故障率高、维护困难等缺点,提出了一种基于采煤机主电缆内嵌单根射频同轴电缆的多路视频、音频及数据综合传输系统的设计方案。该系统采用数据调制传输频率高于视频监控信号调制频段的设计方法,避免了数据通信对监控图像质量的影响,且因数据传输具有较高的功率余量,保障了控制数据通信的低误码率。     

Circularly polarized planar monopole antenna for ultrawideband applications

A broadband circularly polarized (CP) planar monopole antenna is proposed here for ultrawideband (UWB) communication. The antenna is composed of a modified annular ring patch fed by a tapered microstrip line and a rectangular semiground plane on the opposite side of the substrate. Capability of generating wide axial ratio bandwidth (ARBW) is another feature of the proposed antenna. Wide ARBW is achieved by introducing a rectangular slot and a stub in the ground plane. The CP antenna has an impressive ARBW of 5.52 GHz (81.42%, 4.02‐9.54 GHz) within the UWB frequency range (3.1‐10.6 GHz). Measured 10‐dB return loss bandwidth of the proposed antenna is 120.86% centered at 7.48 GHz (2.96‐12 GHz). The proposed antenna is well used for wireless local area network (5.2 and 5.8 GHz), Worldwide Interoperability for Microwave Access (5.5 GHz), and other wireless systems in C band as well as CP‐UWB antenna communication.     

无线网络测试系统的设计与实现

4G通信技术是是集3G与WLAN于一体并能够传输高质量视频图像以及图像传输质量与高清晰度电视不相上下的技术产品。LTE作为4G通信的标准技术,提供了极高的数据传输率,同时也极大地改进了核心网性能。同时,LTE小区具有极大的网络覆盖范围,网络结构简洁,并能与IP网很好地融合,具有广泛的应用前景。LTE对于未来高速铁路信息化建设极其重要。本文设计实现的无线网络测试系统将无线通信测量数据与地理信息数据相结合,为铁路无线通信网络的规划与部署提供参考。     

现代化矿井通信技术与系统

提出了由矿用有线调度通信系统、矿井移动通信系统、矿井广播通信系统和矿井救灾通信系统等组成的煤矿井下通信技术体系。提出矿用调度通信系统应采用矿用有线调度通信系统。提出全矿井移动通信系统宜采用WiFi、3G、4G等通信技术。提出矿井广播通信系统既可采用矿用有线调度通信系统远程供电广播技术,也可采用基于以太环网和无源光网络的IP通信技术。提出矿井救灾通信系统应采用无线多媒体通信技术,宜采用WiFi和MESH等通信技术。提出矿井移动通信系统应满足手机脱网通信、基站脱网通信、无线自组织网络、接入煤矿井下有线宽带传输平台等要求。指出在手机脱网通信、接入煤矿井下有线宽带传输平台、无线自组织网络、矿用无线摄像机、基站脱网通信、多功能矿井移动通信系统、矿井无线宽带传输等方面,WiFi优于WCDMA、CDMA2000和TD-SCDMA。提出多功能矿井移动通信系统和矿井无线宽带传输宜采用WiFi。     

图像的无线传输及基于VC++.net的实现

图像的无线传输在家居安全中有着重要的作用。作为一种短距离无线通信标准。蓝牙工作在全球开放的2．4GHz频段，具有跳频快、低功耗、低成本和比较灵活的特点。因此在智能家居系统中用蓝牙传输监控图像是完全可行的。该文分析了蓝牙的技术特点，研究了采用蓝牙传输图像的关键技术，并用VC ．net实现了发送、接收图像文件的整个方案。     

A Parallel Dynamically Reconfigurable Architecture Designed for Flexible Application-Tailored Hardware/Software Systems in Future Mobile Communication

The evolving of current and future broadband access techniques into the wireless domain introduces new and flexible network architectures with difficult and interesting challenges. The system designers are faced with a challenging set of problems that stem from access mechanisms, energy conservation, error rate, transmission speed characteristics of the wireless links and mobility aspects. This paper presents first the major challenges in realizing flexible microelectronic system solutions for future mobile communication applications. Based thereupon, the architecture design of flexible system-on-chip solutions in the digital baseband processing for future mobile radio devices is discussed. The focus of the paper is the introduction of a new parallel and dynamically reconfigurable hardware architecture tailored to this application area. Its performance issues and potential are discussed by the implementation of a flexible and computation-intensive component of future mobile terminals.An erratum to this article can be found at     

基于RTP的H.264视频流实时打包传输的研究

随着无线宽带网络的快速发展,以及高效的视频压缩技术的应用,流媒体的实时高效传输成为亟待解决的问题。本文从视频传输系统模型入手,分析了最新视频编码标准H.264在算法上的层次结构特点以及音、视频实时传送协议RTP的高效性。并且随着适合H.264流的RTP载荷格式的提出,基于RTP的H.264流媒体无线传输渐渐地得到应用。本文成功实现了一种基于RTP的H.264传输算法,实验通过了TD330无线3G模块测试,并且获得良好的图像质量,实现了低时延、较小丢包率的打包算法。     

Implementation of hybrid fractal metamaterial inspired frequency band reconfigurable multiband antenna for wireless applications

In the present paper authors propose the design and analysis of a hepta band metamaterial inspired octagonal shape antenna using hybrid fractals for wireless applications. Multiband characteristics in the designed antenna is accomplished by introducing of slotted octagonal shape radiating part with hybrid fractal form of Moore curve and Koch curve and two SRR cells. The frequency band reconfigurability is obtained with aid of PIN diodes placed inside the strips connected between Moore curve (fused with centered Koch curve) and feedline. During ON mode of PIN diode antenna operates at seven microwave frequency S‐band WiMAX (3.4~3.69 GHz—IEEE 802.16e)/Lower C‐band terrestrial fixed and mobile broadband application (4.25~4.76 GHz)/C‐band WLAN (5.15~5.35/5.75~5.825 GHz—IEEE 802.11a] (5.4~5.9 GHz)/Lower X‐band Earth exploration‐satellite service ITU region 2 (7.9~8.4 GHz)/Upper X‐band Amateur satellite operating band (10.45~10.50 GHz)/Lower Ku‐band Radar communication application (13.25~13.75 GHz)/Middle Ku‐band Geostationary satellite service (14.2~14.5 GHz) covering various wireless applications. Proposed design exhibit hexa/hepta band features during OFF/ON mode of PIN diode. An acceptable gain, stable radiation characteristics, and good impedance matching are observed at all the resonant frequencies of the proposed structure.     

认知无线电技术在ZigBee中的应用研究

目前多种无线通信技术共享2．4GHzISM频段,它们之间的相互干扰以及频谱重叠现象已成为人们非常关注的一个问题。文中将认知无线电技术应用到ZigBee网络通信中,针对2．4GHz频段,利用认知无线电的频谱感知功能,对信道状态进行检测,搜寻频谱空穴,并且对频谱进行长期感知和统计,使ZigBee用户选择最可能空闲的频段作为传输信道,同时提出了一个2．4GHz无线环境感知模型。该方法提高了ISM频段的频谱利用率,并且减少了同频段其他多种无线通信技术对ZigBee产生的干扰,保证了ZigBee信号的有效传输。     

基于非平稳时频分析的无线网络信道均衡算法

在无线网络数据通信中,由于阵元码间干扰导致信道具有非平稳特性,产生信道失衡效应,需要进行信道均衡设计,提高无线网络的数据传输性能.传统方法采用Hilbert变换扩频方法进行通信信道均衡,通过Hilbert变换使离散数据解析化,由于信道多径扩展导致码间干扰,为了提高信道均衡效果,提出一种基于非平稳时频分析的无线网络信道均衡算法.构建无线网络数据传输的空间多径信道模型,采用时频分析方法进行通信信号码间干扰抑制处理,采用提取的时频特征对通信信道进行正交频分复用分解,采用时频特征分析方法,对相位偏移进行空间码元重组,去掉路径相移偏量,实现信道均衡.仿真结果表明,采用该算法具有较好的信道均衡性能,能有效抑制通信信道的码间干扰,降低无线网络数据通信的误比特率,改善通信质量.