大气激光通信湍流效应分析与仿真

OFDM（正交频分复用）系统以其抗多径衰落和较高的频带利用率，得到了众多领域的广泛应用。本文就OFDM系统中关键技术之一的信道估计技术进行了介绍。并分别叙述了OFDM系统和信道估计的意义，归纳了信道估计的分类，最后介绍了MMSE、LS及其改进信道估计算法并仿真出结果。(OFDM（orthogonal frequency division multiplexing) has been widely used in many areas for its good resistance to multipath fading and high bandwidth efficiency.In this paper,channel estimation,which is one of the key technologies in OFDM systems,were introduced. Then we discuss the significance of the channel estimation and the classification of channel estimation.Finally,we study the algorithms of channel estimation such as MMSE,LS and LMMSE,and further get the simulation results. )

说明：  实现了一个直接扩频系统，使用BPSK作为调制解调方法。并比较白噪声AWGN及瑞利衰落(rayleigh fading)环境下，误码率的影响。(There are two files in the zip folder. bpsk_spread.m and jakesmodel.m Steps for simulation: 1] Run jakesmodel.m first 2] Then run bpsk_spread.m . 3] Note that during the first run bpsk_spread.m has no rayleigh fading.This is because the corresponding code has been commented 4] The resulting performance is stored in BER_awgn. 5] Now uncomment the Rayleigh Fading code in bpsk_spread.m file. 6] Same time comment BER_awgn (line 112) and uncomment BER_ray variable. 7] Run the simulation. To compare the perfromances of the receiver using DSSS plot the BER_awgn and BER_ray >>semilogy([1:8],BER_awgn(1:8), g* ) hold on semilogy([1:8],BER_ray(1:8), -.b* ) hold on grid on )

BPSK的扩频和调制的matlab程序，其中扩频码为m序列，包含产生m序列的matlab程序。(BPSK spread spectrum modulation matlab program, the spreading code of m-sequence contains sequence matlab program generates m.)

说明：  该文档提供ASK,BPSK,QPSK,4QAM,16QAM等多种调制格式的LMS时域均衡算法，最初结构由MathWorks提供。(This document provides LMS time domain equalization algorithms in ASK, BPSK, QPSK, 4QAM, 16QAM and other modulation formats. The original structure is provided by MathWorks.)

说明：  主动锁模光纤激光器，利用强度调制器在腔内产生周期性的损耗调制，产生了超短脉冲。(Active mode-locked fiber)

雷达点迹关联与点航关联的matlab程序(Matlab program of radar dot correlation and dot correlation)

外辐射源雷达中直达波对消matlab程序，使用自适应滤波的算法(adaptive_filter algrithm)

5G 网络 matlab 仿真 5G网络场景模拟 仿真 matlab代码，可运行(Matlab simulation of 5G network)

说明：  使用python基于numpy编写函数和程序，完整实现了SC-FDE链路的仿真，包括调制、成型滤波、信道、同步、频偏补偿、均衡、解调。(Full realization of SC-FDE link simulation using python with functions based on numpy.)

learning c++. it is good for start and beginners