mqtt收发

说明：  迭代信道估计，ls信道估计方式 MMSE均衡 迭代了四次(4times iterative channel estimation with LS and MMSE)

CDMA技术原理与发展，以及MATLAB仿真源代码(Principle and Development of CDMA Technology and MATLAB Simulation Source Code)

this is a paper for pcf beam splitter!

默认产生（0，1）的高斯随机数，参数可调(Gauss random number (0,1) is generated by default with adjustable parameters.)

说明：  51单片机MODBUS主机通信程序，平台KEIL4。使用MODBUS SLAVE测试成功。(51 MCU MODBUS host communication program, platform KEIL4. The MODBUS SLAVE test was successful.)

costas环解调程序，需要的可以参考一下。costas环解调.m(It is a matlab code for demodulation as costas ring .if you are interested in it, you can refer to it.)

wcdma里面扩频所需的0号扰码源文件,并产生S行曲线,实现超前滞后门位同步()

一个C++的简单的原代码,可以提供学习比较好,大家可以下了(C of a simple code, can provide a better learning, we can go down)

说明：  5. 在三条径的瑞利信道中，对于直接序列扩频： (1) 请设计DS-CDMA一种具体的码分导引辅助的信道估计方法，接收机分别采用等均益合并、最大比合并。用Simulink进行仿真，画出比特信噪比与信道估计均方误差的关系曲线和比特信噪比与误码率的关系曲线。 (2) 设频率已经同步，请设计DS-CDMA一种具体的单停顿滑动相关时间同步方法，用Simulink进行仿真，画出比特信噪比与捕获概率的关系曲线。 (3) 设时间已经同步，请设计DS-CDMA一种具体的频率同步方法，用Simulink进行仿真，画出比特信噪比与频率同步误差的关系曲线。(5. In three-path Rayleigh channel, for direct sequence spread spectrum: (1) please design a specific code division navigation aided channel estimation method for ds-cdma, and adopt equal-beneficial combination and maximum ratio combination for receivers respectively.Simulink is used to simulate and draw the relationship curve between bit SNR and channel estimation mean square error and the relationship curve between bit SNR and bit error rate. (2) assuming that the frequency has been synchronized, please design a specific single-stop sliding correlation time synchronization method ds-cdma, Simulink simulation, draw the relationship between the bit SNR and the acquisition probability curve. (3) if the time has been synchronized, please design a specific frequency synchronization method ds-cdma, Simulink simulation, draw the relationship between the bit SNR and frequency synchronization error curve.)

说明：  使用改进的遗传算法来优化一维周期稀疏线阵(Using improved genetic algorithm to optimize one-dimensional periodic sparse linear array)