方向图

energy efficiency code for cognitive radio

读取CORS数据，重采样成30秒，计算电离层总电子含量(Read CORS data, resampling into 30 seconds, calculate the total electron content of the ionosphere)

说明：  ：载波频率偏移是OFDM系统实现的关键问题之一。分析了OFDM 系统载频偏移估计的2 种算法，即利用循环前缀和训练序列方法。它们均为最大似然估计方法。分别讨论了它们的基本 思想、实现方法和仿真结果。可以看出基于循环前缀算法复杂度较小，精度不高，而基于训练序列 的算法有较高的估计精度，但降纸了系统传输效率。(Abstract：Carrier frequency ofset is one of the key problems in OFDM system．Two foundational methods 。cycling prefix—based and training sequence—based algorithms。to estimate OFDM carriers~equency ofset are analyzed．Then it discusses their basic thoughts。implementing methods and simulation resuits． Finally。merits and demerits of every algorithm are supposed．It concludes that the cycling prefix— based algorithm has less complexity and less precision。and that the training sequence—based algorithm has better estimation performance at the cost of transmission efficiency．)

用于检测手机麦克风输入音量大小的DEMO(it s used to detect the volume of phones micphone)

可以实现无线通信，代码简单便于理解，是基于wince平台的(Wireless communications can be achieved, the code simple and easy to understand, is based on the wince platform)

matlab中使用FFT算法求两个信号的时频二维（互模糊）函数，可以实现信号的时延、多普勒频移联合估计（需要根据实际场景适当修改参数）(oint estimation matlab frequency two-dimensional FFT algorithm seeking the two signals (cross ambiguity) function, signal delay, Doppler shift)

说明：  matlab基础入门，适合新手学习matlab基础操作与功能(Introduction to matlab)

说明：  中国的手机游戏市场用户调研报告2008年度(China mobile phone game market research report of 2008 users)

（1）请推导出单径瑞利信道中的BPSK相干解调的理论误码率性能，并画出比特信噪比与误码率的关系曲线。 （2）在单径瑞利信道中，请设计一种时分的导引辅助的信道估计方法，用Simulink进行仿真，测量BPSK的误码率性能，画出比特信噪比与误码率的关系曲线，并与(1)的曲线进行对比。 ((1) derived from single-Path Rayleigh channel coherent demodulation of BPSK theoretical bit error rate performance and draw-bit signal to noise ratio and bit error rate curve. (2) in a single Path Rayleigh channel, please design a guided night-assisted channel estimation methods, using Simulink simulation, surveying BPSK BER performance, drawn-bit signal to noise ratio and bit error rate curve, and with (1) comparing the curve.)

OFDM channel estimation DFT single document, ultra-detailed, very helpful for understanding OFDM, but also helpful for understanding how to simulate channel estimation