(精品word)cdma的MATLAB仿真源程序.doc

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％ This function pertains to the addition of AWGN with mean zero and

％ parameter 'variance' to an input signal。

％

％ AUTHOR： Wenbin Luo

% DATE ： 04/12/01

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function y = awgn(x，var)

w = randn(1,length（x)）；

w = w — mean(w)*ones(size（w）)；

w = sqrt(var)＊（w / std(w))；

x = x（：)；

w = w(:)；

y = x + w；

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％ SYNOPSIS: y = ds_mod（c，x)

% x —-—〉 input signal (row vector）

% y --—> tmp = c＊x, y = tmp（:） （ds-ss modulated signal， column vector)

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% This function generates random +1/-1 sequence with independent identically

% distributed symbols

％

％ AUTHOR： Wenbin Luo

% DATE ： 04/28/01

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％ SYNOPSIS： x = bingen(L)

％ L -——〉 number of random symbols

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％ This function does the DS-SS modulation

%

% AUTHOR： Wenbin Luo

％ DATE ： 04/28/01

％

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function x = ds_demod（c,y)

tmp = reshape（y， length(c）， length(y)/length（c)）；

tmp = tmp'；

%x is a column vector

x = tmp * c；

% convert to row vector

x = x'；

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％ SYNOPSIS: y = ds_mod（c，x）

% x —-—> input signal (row vector)

％ y ——-> tmp = c＊x, y = tmp(:） （ds—ss modulated signal， column vector)

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%

% Parameter Description：

% L : number of samples needed

% variance ： variance

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function [env，phi] = fade(L，variance）

％ Error check

if variance 〈= 0

error(’Positive variance needed'）

error('Insufficient input parameters’)

end

% Generate bivariate Gaussian uncorrelated

% random variables

mu = zeros(1,2）;

C = variance＊eye（2,2)；

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％ This mfunction generates two channels of faded

％ envelope and phase corresponding to

％ Rayleigh fading

%

％ AUTHOR： Wenbin Luo

% DATE ： 04/27/01

％

％ FUNCTION SYNOPSIS：

% ［env，phi］ = fade_diversity（L,para）