数字相关和卷积运算Correlation and Convolution
相关可以从时域角度表现信号间的相似 程度,可以用来作为滤波和识别分类手段。卷积是线性时不变系统分析中基本的运算,也可 以起到滤波的作用。
相关可以从时域角度表现信号间的相似 程度,可以用来作为滤波和识别分类手段。卷积是线性时不变系统分析中基本的运算,也可 以起到滤波的作用。
Digital Communication over Fading Channels
单载波频域均衡系统的原理,结构,和系统性能分析
Simulation of Communication SystemsSecond Edition
东南大学 硕士学位论文 MIMO信道估计及频域均衡的研究与实现 姓名: 刘澍 申请学位级别: 硕士 专业: 信号与信息处理 指导教师: 杨绿溪
This report discusses the design and implementation of an OFDM modem for a simplex com- munication between two PCs over a frequency selective channel. First a brief introduction is provided by explaining the backrground and the speci?cation of the project. Then the report deals with the system model. Each block of the OFDM system is described (IFFT/FFT, cyclic pre?x, modulation/demodulation, channel estimation, bit loading). In the following section, the system architecture is analysed. The transmission protocol, as well as the system parameters are explained in details. Then, the DSP implementation is discussed. Finally, the results are provided in the last chapter.
本文介绍了移动通信信道的基本理论,对移动通信中的衰落信道,如Rician信道和 Rayleigh信道进行了分析和建模。在此基础上通过使用MATLAB仿真软件,采用相关算法编程 对平坦衰落信道进行仿真,仿真结果表明了信道分析的有效性。
在单载波频域均衡系统中,提出了一种高效利用已知接收数据进行子空间盲信道估计的方法。对每个接 收数据块内的符号进行循环移位,将原一列数据向量扩展为两列行线性非相关数据矩阵。因此,在相同均衡性能 指标下,所利用的接收数据量是以往使用的子空间盲信道估计方法的一半。这意味着,此方案适用于某些对数据 量有严格限制要求的场合。仿真实验结果表明,在保证性能无衰减的前提条件下,节省一半的所需数据量
Orthogonal Frequency Division Multiplexing (OFDM) is a powerful technique employed in com- munications systems suering from frequency selectivity. Combined with multiple antennas at the transmitter and receiver as well as adaptive modulation, OFDM proves to be robust against channel delay spread. Furthermore, it leads to signicant data rates with improved bit error performance over links having only a single antenna at both the transmitter and receiver. This project demonstrates OFDM with adaptive modulation applied to Multiple-Input Multiple- Output (MIMO) systems. We apply an optimization algorithm to obtain a bit and power al- location for each subcarrier assuming instantaneous channel knowledge. The analysis and sim- ulation is considered in two stages. The rst stage involves the application of a variable-rate variable-power MQAM technique for a Single-Input Single-Output (SISO) OFDM system. This is compared with the performance of xed OFDM transmission where a constant rate is applied to each subcarrier. The second stage applies adaptive modulation to a general MIMO system by making use of the Singular Value Decomposition to separate the MIMO channel into parallel subchannels. For a two-input antenna, two-output antenna system, the performance is compared with the performance of a system using selection diversity at the transmitter and maximal ratio combining at the receiver