MAPPING OF MPSK AND QAM FROM BINARY TO GRAY

MAPPING OF MPSK AND QAM FROM BINARY TO GRAY

clc;
clear all;
close all;
N = randint(1,1000); % generating symbols

% mode type
m_type=input('Enter the modulation type[ BPSK,2 QPSK,3 8PSK,4 16QAM]: ');

factor=[1;1;1;1];

b=[1;2;3;4]; % number of bits per subcarrier, 1:BPSK,2:QPSK,4:16QAM

input_sequence = N;

k=factor(m_type);

m=b(m_type);
% Selecting constellation as per modulation
switch m
case 1
b=k*[1 -1];
case 2
b=k*[1+1i -1+1i 1-1i -1-1i];

case 3
b=k*[(cos(0)+1i*sin(0)) (cos(pi/4)+1i*sin(pi/4)) (cos(pi/2)+1i*sin(pi/2)) (cos(3*pi/4)+1i*sin(3*pi/4)) (cos(pi)+1i*sin(pi)) (cos(5*pi/4)+1i*sin(5*pi/4)) (cos(6*pi/4)+1i*sin(6*pi/4)) (cos(7*pi/4)+1i*sin(7*pi/4))];
case 4
b=k*[1+1i 1+3i 1-1i 1-3i 3+1i 3+3i 3-1i 3-3i -1+1i -1+3i -1-1i -1-3i -3+1i -3+3i -3-1i -3-3i];

end

c1=1;
c2=1;

for i=1:(ceil(length(input_sequence)/m))
temp=0;
for j=1:m
temp=bitor(temp,bitshift(input_sequence(c1),(j-1)));
c1=c1+1;
if(c1>length(input_sequence))
break;
end
end
map_out(c2)=b(temp+1);
c2=c2+1;
end

% plot
figure;
plot(real(map_out),imag(map_out),'k.');
axis ([-5 5 -5 5]);
title('CONSTELLATION');