how to generate qpsk signal

I am trying to generate a qpsk signal. I have code for the generation of a bpsk signal and I want a similar one for qpsk. What can I change in my code below to make the results that of qpsk. Below is the code for bpsk;

 clear;
clc;
close all;
N=1024;
rN=rand(1,N);
rBinary=round(rN);
Fc=2;
Fs=4;
nCycles=1;
Tb=nCycles/Fc;
t=0:1/Fs:(nCycles-1/Fs);
xC=cos(2*pi*t);
A=1;
Eb=(A^2*Tb)/2;
Eb_N0dB=0:2:14;
Eb_N0=10.^(Eb_N0dB/10);
nVar=(Eb)./Eb_N0;
bitStream = [];
carrierSignal = [];
i = 1;
while(i<=N)
    if(rBinary(i))
        bitStream = [bitStream ones(1,length(xC))];
    else
        bitStream = [bitStream zeros(1,length(xC))];
    end
    carrierSignal = [carrierSignal A*xC];
    i = i+1;
end
bits = 2*(bitStream - 0.5)
bpskSignal = carrierSignal.*bits;
figure(1);
subplot(3,1,1);
plot(bitStream);
title('Digital signal');
xlim([0 300]);ylim=([-0.2 1.2]);
subplot(3,1,2);plot(carrierSignal);
title('Carrier signal')
xlim([0 300]);ylim=([-0.2 1.2]);
subplot(3,1,3);plot(bpskSignal);
title('BPSK');
xlim([0 300]);ylim=([-0.2 1.2]);
subplot(3,1,2);plot(carrierSignal);
  end

Answer 1

[DHWANI VIJAYAN]

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