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上海大学 20072008学年春季学期研究生课程考试课程名称: 电子科学与技术进展 课程编号: 071000905 论文题目: WiMAX物理层系统架构及其抗快衰落算法研究 研究生姓名: 石 强 学 号: 07720763 论文评语:成 绩: 任课教师: 评阅日期: WiMAX物理层系统架构及其抗快衰落算法研究摘要:随着信息产业的飞速发展,通信技术和计算机技术的融合已成为必然趋势,全球通信产业呈现出移动化、宽带化、PI化的趋势。IEEE802.16e的出现正好迎合了这样的发展趋势,基于EIEE802.16e的WiMAX技术兼具了移动、宽带和PI化的特点,是一种很有发展潜力的无线接入技术。WiMAX是IEEE提出的一种基于802.16标准的解决方案,它是一种无线宽带接入技术,可以提供高达70Mbit/s的数据传输速率,而且可以支持一定的移动性和基于VoIP的语音业务。WiMAX主要为固定、便携或者低速移动的用户提供接入服务,满足热点地区的高速数据业务的需求,但现阶段WiMAX并不支持高速移动下的无缝漫游。本文首先简要介绍WiMAX技术及其参考模型和关键技术,然后对WiMAX的发射机和接收机工作过程进行了详细描述,分析了该系统物理层的基本原理,在此基础上,构建了一个典型的Wireless WiMAX-OFDM系统仿真模型与框架,给出了系统性能的基本仿真结论。该系统仿真模型与框架对WiMAX系统的优化设计、缩短系统的开发周期具有十分重要的意义。对于整个WiMAX基带通信平台,在设计整个FIR滤波器过程中可以充分的体现整个平台的优秀架构所带来的算法实现设计的便利。基于matlab仿真软件,在NLOS 环境下的802.16 OFDM PHY 的基带模型后仿真,为后续的系统层计算机仿真和多用户模式计算机仿真提供了良好的理论基础,为FPGA/DSP 设计提供了技术参考 其次,在移动通信系统中,由于衰落和多普勒效应,需要不断跟踪信道参数变化,就需要进行信道估计。于是还结合了WiMAX技术,研究了衰落信道模型及算法,并对算法进行了仿真,给出了衰落信号的仿真结果。仿真了一些典型的信道估计算法,并给出了仿真结果。还从技术、应用和市场的角度对WiMAX与3G等现有网络进行了分析比较,指出现阶段它们各自的技术特点、应用场所及目标用户。两者的最终发展目标是趋同的,都是要实现无线接入的宽带化和移动化,最终两者的竞争将不断扩大。最后总结了所研究的内容,并指出了下一步的研究工作。关键字: 全球微波接入互操作性;物理层;正交频分复用; 快衰落;信道估计Research on system architecture of the physical layer in WiMAX and its anti-fast fading AlgorithmAbstract:With the fast development of information industry, the integration between communication technology and computer technology has become is an inevitable trend. the trend of Mobile, broadband, PI are Shown in the global mobile communications industry. IEEE802.16e meet the emergence of such a development trend precisely WIMAX systems which based on IEEE802.16e standard hold all the traits of Next Generation Mobile Communication systems. Therefore, Mobile WIMAX is a very Promising Broadband Wireless Access technology. WiMAX which based on the IEEE 802.16 standard-based solutions, is a wireless broadband access technology that can provide data transmission rates of up to 70Mbit/s.Moreover, it can support mobile and VoIP-based voice business. WiMAX is mainly fixed, portable or mobile users with low-speed access services, the hot-spot areas to meet the needs of high-speed data. However, at present, high-speed mobile WiMAX does not support the seamless roaming. Firstly, this paper gives a brief introduction about WiMAX and its reference model and key technology. Then it describes the operation procedure of the WiMAX transmitter and receiver,analyses the basic principle of the system physical layer,and on this base,a typical Wireless WiMAX -OFDM system simulation model and framework are designedThe system simulation model and framework may help to deeply research and discuss the Wireless WiMAX-OFDM system and is very important for the optimized design of WiMAX system and also shortening the system developing cycleThe entire design process of the FIR filter can embody the convenience in algorithm realization,which is resulted from the excellent framework of the whole platform. The channel simulation of 802.16/WiMAX on NLOS communication environment using MATLAB is studied. By simulating the base-band model based on 802.16 OFDM PHY, it evaluates the major capabilities with different modulate modes. The study offers theory base for computer simulate in system layer and technical reference for FPGA/DSP design. Secondly, in mobile communication system, channel estimation and tracing method is needed to track channel parameters due to the channel fading and the Doppler effect. Then a fading channel model and the algorithm are given and the algorithm which anti-fading channel is simulated. The simulation results and the input signal processed by the channel are given. Some typical channel estimation algorithms are simulated, and the simulation results are given. And compares WIMAX with the 3G in the aspects of technologies, application and market, it points out that they have different technology characters, application environments and aiming users. The ultimate goal of both is the convergence of development, are to achieve the broadband wireless access and mobile, and eventually the two will continue to expand the competition. Finally, the paper sums up the contents of the study and pointed out the next step of research.Key words:WiMAX; Physical Layer; OFDM; Fast fading; Channel estimation 1、 引言随着通信技术的日新月异和市场的需求,高速有效的宽带无线服务已迫在眉睫。现今,简单的语音,低数据率业务已经无法满足需求,无线宽带移动化与高速高效化已成为3G的发展趋势。2007年10月19日下午,在日内瓦召开的国际电信联盟(ITU)无线通信(Radio Assembly)全体会议上无线宽带技术WiMAX正式成为3G标准 。于是,WiMAX就与WCDMA、CDMA2000、TD-SCDMA并列为四大3G国际标准。WiMAX宽带无线技术现已作为一种有效的宽带接入网解决方案得到了全球移动产业的认可。另外,由于快衰落一直是蜂窝移动通信研究的重点。其实,无线通信中的很多研究工作也都是围绕着如何抵抗信道衰落这一问题而展开的。为了从接收信号中恢复被传输的原始信号,必须要有合乎实际的高效算法来处理接收信号。在大多数这类算法中,对信号传输的信道进行正确的估计是最为关键的技术。无线通信的快衰落信道估计问题是信息与通信处理领域中经典问题, 目前,WiMAX支持的速度只有120km/h,随着磁悬浮、高速铁路等交通工具的大力发展,移动速度超过120km/h的移动终端将会大量使用,如何实现高速移动终端的高效接入是一个严峻的挑战。由于移动信道中接收信号的快衰落是影响通信质量的主要因素, 因
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