脉冲噪声下的OFDM系统的多用户检测性能研究推荐.doc

毕 业 论 文（设 计） 题 目 脉冲噪声下的OFDM系统多用户检测 性能研究 英文题目The Performance of OFDM System Multi-user Detection under Impulse Noise 摘 要 OFDM (正交频分复用)的基本原理是将高速的数据流分解成许多低速率的子数据流，利用相互正交且重叠的多个子载波同时传输。它的主要优点是多径失真低，抗符号间干扰(ISI)能力强，频带利用率很高。因此，人们开始关注正交频分复用（OFDM）系统，希望通过这种技术来解决高速信息流在无线信道中的传输问题，从而可以满足带宽要求更高的多种多媒体业务和更快的网络浏览速度。 本论文详细地介绍了OFDM系统和脉冲噪声的基本原理。根据整个系统的功能，编写了脉冲噪声、扩频、OFDM系统以及误码率模块的MATLAB程序，用MATLAB软件对脉冲噪声下的OFDM系统多用户检测整个系统进行仿真。 最后对仿真的结果进行分析。通过仿真得出系统的误码率波形，对系统性能进行分析，并进一步对系统改进和调试。仿真结果证明了整个系统的可行性。由误码率的波形可以看出，当某一特定值时，整个系统的误码率随信噪比的增大而减小。另外，研究表明较小的脉冲噪声比较大的脉冲噪声所造成的误码影响要大得多，且=2的脉冲噪声所造成的误码率在信噪比较小的情况下即可达到0。 【关键词】：正交频分复用（OFDM）；脉冲噪声；扩频/解扩；误码率；多用户检测 Abstract The basic principle of OFDM (orthogonal frequency division multiplexing) is that dividing high-speed data stream into many low-rate sub-data streams, and using multiple orthogonal and overlapping sub carriers to transmit simultaneously. Its main advantages are low multipath distortion, anti-inter-symbol interference (ISI) capacity and high bandwidth efficiency. Therefore, people are focusing on orthogonal frequency division multiplexing (OFDM) system, and hoping to solve the problems of high-speed data streams transmission in the wireless channel through this technology. So the higher bandwidth requirements to a variety of multimedia services and faster Web browsing speed are met. This paper describes the basic principles of OFDM system and impulse noise in detail. According to the function of the entire system, I write the MATLAB program of impulse noise, spectrum-spread, OFDM system and bit error rate module, and simulate the entire system through MATLAB software. Finally, through the BER simulation waveforms by simulation , I improved and the system furtherly . The simulation results show the feasibility of the system. By the error rate waveform can see that when is a particular value in 0 to 2, the overall system bit error rate increases with signal to noise ratio. In addition, study shows that the small impulse noise cause much gre