NOMA concept

TDMA simulation using OPNET modeler

巴特沃斯滤波器C语言实现,低通滤波器,IIR(Butterworth filter C language implementation, low pass filter, IIR)

该程序为LTE中3GPP协议的PUSCH信道的物理资源映射程序，可进行物理层链路的资源映射部分(The program is a physical resource mapping program for the PUSCH channel of the 3GPP protocol in LTE, and the resource mapping part of the physical layer link)

这是opnet 建立无线网络模型的教程,对于初学opnet仿真的学者很有帮助(This is set up a wireless network model of OPNET tutorial for beginners and scholars OPNET Simulation helpful)

This thesis presents simulation data on array operation in wideband communication systems. It is shown that array structures with closer inter-element spacing outperform structures with much larger inter-element spacing. It is also shown that circular structures outperform linear structures. This performance dierence between the classications of arrays is due largely to the circular array s ability to handle high levels of interference. Even though a diversity combining scheme (MRC) was used in the simulator, the arrays provided interference rejection capabilities due to the closely spaced antenna elements.

接收端采用的算法和程序流程与发送端发送的OFDM符号的帧结构有关系。具体的帧结构，以及定时估计，频偏估计，剩余误差跟踪的算法可参考算法说明文档。这里对程序的流程进行说明。 首先根据短训练字的特性进行相关运算，进行信号到达检测，当检测到相关值大于门限一定次数后，认为有信号到达。然后根据长训练字的特性，进行相关运算，进行OFDM符号FFT窗口起始位置的估计。估计出FFT窗口的位置后，先在时域进行小频偏的估计，将两个长训练字进行小频偏补偿后，进行FFT运算，根据FFT运算的结果进行整数倍频偏的估计。这些参数估计完成后，就可以进行数据解调了。先对数据部分进行完整的频偏补偿，然后根据估计的FFT窗口位置进行FFT运算得到频域的数据，进行解调。然后在对应于导频的子载波位置上提取出导频信息，根据导频信息估计出剩余定时误差以及剩余的信道响应误差，将误差量送入环路进行跟踪。当收到所有数据后，重新回到信号到达检测状态，进行下一次信号到达的检测和信号接收。 (good)

实现通信系统的数字模拟混合预编码，进行干扰抑制，提高系统性能，降低硬件复杂度和实现成本(The digital analog hybrid precoding of the communication system is realized, the interference suppression, the performance of the system, the complexity of hardware and the cost of realizing the system are reduced.)

说明：  In this paper, a new direction-of-arrival (DOA) estimation method based on multiple Toeplitz matrices reconstruction is proposed for coherent narrow band signals with a uniform linear array (ULA).(Even in the case of a low signal-to-noise ratio and low snapshot number with half the array aperture reduced, the new method provides good performance on estimation and resolution.)

stm32f4xx 官方标准外设固件库 ，含有多种类型的设计案例(Stm32f4xx official standard peripheral firmware library, containing a variety of design cases)

一个详细讲述卡尔曼滤波的ppt，通过它可以学习有关卡尔曼滤博，和机器人自主定位的知识( Kalman filter detailed ppt, through which you can learn more about Bo Kalman filter, and knowledge of robot autonomous localization )