cczffinal.m

自己编写的zero forcing equalizer

%-------------------------------------------------------%
%Name:        Zero Forcing equalizer
%Function:    simulate transmission with ZF equalizer
%             the number of tap of the equalizer is 3
%Author:      Group 
%Create date: 2008-11-16
%-------------------------------------------------------%
clear all;
close all;
training_bits = [1 -1 -1 1 -1 -1 1 -1 -1 1 -1 1 -1 1 1];
vv =zeros(1,4);

%retrain the channel for several times to get accurate estimation
train_time = 100;
%for (ii = 1:train_time)
    v = linch(training_bits);   %pass through the channel
%    vv = vv + v(1:4);
%end
%vv = vv/train_time;
% U = [vv(3) vv(2) vv(1);
%       vv(4) vv(3) vv(2);
%       0 vv(4) vv(3)]';
U = [v(11) v(10) v(9) v(8) v(7) v(6) v(5);
    v(12) v(11) v(10) v(9) v(8) v(7) v(6);
    v(13) v(12) v(11) v(10) v(9) v(8) v(7);
    v(14) v(13) v(12) v(11) v(10) v(9) v(8);
    v(15) v(14) v(13) v(12) v(11) v(10) v(9);
    v(16) v(15) v(14) v(13) v(12) v(11) v(10);
    v(17) v(16) v(15) v(14) v(13) v(12) v(11)];
P = inv(U);
Czf = P*[0;0;0;1;0;0;0];

buf_BER = [];
N = 10;
bn = sign(rand(1,N)-0.5);
rn = linch(bn);
re = conv(rn,Czf);
bn_est = sign(re);       %shift the position to avoid time delay
%BER = sum(abs(bn_est - bn)/2)/N;%calculate BER
%buf_BER = [buf_BER BER];        %buf the result


%test the zero forcing equalizer
% test_time = 100;
% buf_BER = [];
% % test for more times for ploting
% for(ii = 1:test_time)
%     N = 100000;
%     bn = sign(rand(1,N)-0.5);
%     rn = linch(bn);
%     re = conv(rn,Czf);
%     bn_est = sign(re(4:N+3));       %shift the position to avoid time delay
%     BER = sum(abs(bn_est - bn)/2)/N;%calculate BER
%     buf_BER = [buf_BER BER];        %buf the result
% end
% %draw the target BER
% target = zeros(1,length(buf_BER))+ 0.005;
% figure(1)
% n = 1:length(buf_BER);
% plot(n,target,'r-.');
% hold on;
% %draw the real BER
% plot(buf_BER,'x');
% axis([1 test_time 0 0.05]);
% legend('Target BER','Real BER');