ML_detection_Matlab

实现ldpc 编译码功能，并且输出BER和曲线图。(LDPC encoder and decoder)

OFDM 同步技术研究 Schmidl_Cox算法 定时估计matlab程序(OFDM the synchronization technology research S&C algorithm timing estimation)

基于matlab的QPSK调制与解调程序(QPSK modulation and demodulation)

本文档，分别描述了LTE上行PUSCH信道，PUCCH信道，PRACH信道的基带信号处理流程(This document describes the LTE Uplink PUSCH each channel, PUCCH channel, PRACH channel baseband signal processing)

wireless communication channels model

simulink model for QPSK Rayleigh channel

OFDM系统包括OFDM系统的调制解调，IFFT及FFT变换，保护间隔的加入对系统性能的改善，以及多径干扰、高速移动对系统误码率的影响。(The OFDM system includes modulation and demodulation of the OFDM system, IFFT and FFT transformation, the improvement of the protection interval to the system performance, and the influence of multipath interference and high-speed mobile on the system BER.)

By building the generalized Sigmoid function relationship between normalized step-size and the power of error signal, a novel variable step-size NLMS algorithm is proposed. It is proved that the step-size of NPVSS-NLMS changes as the new algorithm does when A=σv -m and B=2. The physical meanings of the parameters in this algorithm are explored. The theoretical analysis illustrate that this algorithm combine the virtues of NPVSS-NLMS and Sigmoid function, and it leads to faster convergence rate and lower final misalignment. The computer simulation results support the theoretical analysis.

matlab，QPSK,通信系统，调制，解调，信号波形，频谱(matlab, QPSK, the communication system, modulation, demodulation, the signal waveform, the spectrum)

LDPC码不同迭代次数对比。码长512，码率1/2，迭代次数分别为0，5，10，50，100.(The LDPC codes different number of iterations contrast. Long code 512, code rate 1/2, the number of iterations were 0,5,10,50,100.)