vblast_decode.m

自适应滤波原理_西蒙.赫金_Matlab_源代码 希望能够对学习自适应滤波技术的朋友有所帮助

function [err] = vblast_decode(snr,Smap)
%Routine to perform optimal order decoding for vblast

global nTx nRx modtype Mary

if nargin == 0,
    clc; clear;
    snr = 12;
    nTx = 2;
    nRx = 2;
    modtype = 'psk';    %'psk' or 'qask'
    Mary = 8;           %Constellation size (how many symbols in the set)
end

%Generate Data
%Possible Symbol Set
%Set=[0:Mary-1]';  
%Smap=dmodce(Set,1,1,modtype,Mary);
%[symb,Smap]=psk_gen(Mary);
%Generate Symbols
%symb=randsrc(nTx,1,[0:Mary-1]);
symb=ceil(rand(nTx,1)*Mary);
%Encode with PSK
%Tx=dmodce(symb,1,1,modtype,Mary);
[Tx]=psk_gen(Mary,symb);
%Generate channel
H=(randn(nRx,nTx) + i*randn(nRx,nTx))/sqrt(2);  %FOR RAYLEIGH TESTING !!!
%Noise Stats
Eav=Smap'*Smap/Mary;
NF=10^(snr/10);
NP=sqrt(nTx*Eav/(2*NF)); %signal power / snr = noise power
noise=NP*(randn(nRx,1) + i*randn(nRx,1));  %Get noise
%Generate received signal
Rx=H*Tx + noise;

%Decode using V-Blast algorithm
%Initialization
yhat = zeros(size(Tx));
G = pinv(H);  %G*H = eye(nRx), remember nRx >= nTx
for j = 1:nTx,
    k(j) = norm(G(:,j));
end
[value,index]=sort(k);
%Recursion
for i = 1:nTx,
    G = pinv(H);
    pos=index(i); %row with smallest norm first, end with largest norm
    w = G(pos,:);
    y = w*Rx;
    %Slice to get best guess transmitted signal
    dst = zeros(Mary,1);
    for p = 1:Mary
        dst(p) = norm(y - Smap(p));
    end
    [u,v] = sort(dst);
    yhat(pos) = Smap(v(1));  %This is always 'v(1)', we want minimum
    %Subtract off contribution
    Rx = Rx - yhat(pos)*H(:,pos);
    %Zero that column of H
    H(:,pos) = zeros(nRx,1);
end
%[Tx yhat]
err = sum(Tx~=yhat);