rayleigh.m

这个程序主要是实现空时编码的matlab编解码仿真。

function [received,alpha,theta]=rayleigh(trans,variance)

%   [received,alpha,theta]=rayleigh(trans,variance)
%
%	Output:
%	received   - Received signal after rayleigh fading channel
%   
%   Input:
%	trans      - Transmitted signal (baseband!)
%   variance   - Variance for the rayleigh fading
%   
%   Short Theoretical Background for the Function:
%
%   puts trans through a rayleigh fading channel 
%   received = alpha*exp(j*theta). Constant alpha 
%   and theta during one block.
%   In baseband!
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
%%% Function part of simulation for Space-Time
%%% coding project, group Grey-2001.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%   Author: Fredrik Hansson
%   Date: 2001-03-28
%   Version: 1.0
%   Revision (Name & Date & Comment):
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

sigma2 = variance;

x = sqrt(sigma2)*randn(1); 
y = sqrt(sigma2)*randn(1);

alpha = sqrt(x^2+y^2);    %rayleigh distributed
%alpha = 0.8378;
theta = 2*pi*rand(1);
%theta = atan(y/x);
received = alpha * exp(j*theta)*trans;