Question

09-13: The figure below shows comparison of the noise performance of different PSK and FSK schemes using closed form formulas. Reproduce the same results using simulations for the following modulation formats. i. Coherent QPSK ii. DPSK Plot both the theoretical and simulation results. 1o-1 1o-2 10-3 2.5

Answer 1

DetectionMethod Coheren Coherent BPSK QPSK M -PSK M-QAM(m = even) | D- BPSK D-OPSK ! 1 -fc(厗sin(t) Coherent Coherent M-1 Non -coherent 0.5e Non-coherentQi(a, b) - 0.Slo(ab)e 0) where a,- | Ada, b) = Marcum Q-function 10(ab) = Modified Bessel-function

clc
close all
EbNodB=-4:1:24   % Signal to Noise Ratio in dB
EbNolin=10.^(EbNodB/10); % Converting SNR to non dB scale
colors={'k-x','r-h'}; %defining Colors to differentiate two Plots
index=1 % fetches colors one by one from previously defined colors sequence

% DPSK

Pb=0.5*exp(-EbNolin); % Biterrorrate calculation
plotHandle=plot(EbNodB,log10(Pb),char(colors(index))); % plot of Bit error rate in dB vs SNR(dB)
set(plotHandle,'LineWidth',1.5); % define plot properties
index=index+1; % increment index value to 2 , to fetch second color

hold on; % plot two graphs in same plot

% Coherent QPSK

Pb=0.5*erfc(sqrt(EbNolin));
plotHandle=plot(EbNodB,log10(Pb),char(colors(index)));
set(plotHandle,'LineWidth',1.5);

Output

QPSK -20 -4아 -60 -80 100 120 -5 10 15 20 25