fix matlab code

$\%$ Define parameters

M $=[2,4,8]$; $\%$ Modulation orders

num$\_$symbols $=1$e$6$; $\%$ Number of symbols to simulate

SNR$\_$db $=-2$:$2$:$20$; $\%$ SNR range in dB

EbN$\_$db $=$ SNR$\_$db $-10*$log$10($log$2($M$))$; $\%$ Convert SNR to Eb$/$N in dB

$\%$ Initialize variables

theoretical$\_$SER$\_$psk $=$ zeros$($length$($EbN$\_$db$),1)$;

theoretical$\_$SER$\_$mfsk $=$ zeros$($length$($EbN$\_$db$),1)$;

simulated$\_$SER $=$ zeros$($length$($EbN$\_$db$),$ length$($M$))$;

$\%$ Loop through modulation schemes

for m $=1$:length$($M$)$

$\%$ Loop through Eb$/$N values

for i $=1$:length$($EbN$\_$db$)$

$\%$ Generate random symbols

data$\_$bits $=$ randi$($M$,$ num$\_$symbols, $1)$;

$\%$ Modulate symbols

if m $==1$

modulated$\_$signal $=$ pskmod$($data$\_$bits, M$)$;

else

modulated$\_$signal $=$ fskmod$($data$\_$bits, M$,2)$;

end

$\%$ Add AWGN noise

received$\_$signal $=$ awgn$($modulated$\_$signal, EbN$\_$db$($i$))$;

$\%$ Demodulate symbols

if m $==1$

demodulated$\_$data $=$ pskdemod$($received$\_$signal, M$)$;

else

demodulated$\_$data $=$ fskdemod$($received$\_$signal, M$,2)$;

end

$\%$ Calculate symbol error rate

simulated$\_$SER$($i$,$ m$)=$ sum$($data$\_$bits ~$=$ demodulated$\_$data$)/$ num$\_$symbols;

$\%$ Theoretical symbol error rate $($MPSK$)$

theoretical$\_$SER$\_$psk$($i$)=$ qfunc$($sqrt$(2*10^($EbN$\_$db$($i$)/10)))$;

$\%$ Theoretical symbol error rate $($MFSK$)$

theoretical$\_$SER$\_$mfsk$($i$)=(1-1/$M$)*$ qfunc$($sqrt$(3/($M$-1)*10^($EbN$\_$db$($i$)/10)))$;

end

end

$\%$ Plot results

figure;

semilogy$($EbN$\_$db$,$ theoretical$\_$SER$\_$psk$,\text{'}$b$-\text{'},$ 'LineWidth', $2)$;

hold on;

semilogy$($EbN$\_$db$,$ theoretical$\_$SER$\_$mfsk$,\text{'}$g$-\text{'},$ 'LineWidth', $2)$;

for m $=1$:length$($M$)$

semilogy$($EbN$\_$db$,$ simulated$\_$SER$($:$,$ m$),\text{'}$o$-\text{'},$ 'MarkerSize', $8)$;

end

xlabel$(\text{'}$Eb$/$N $($dB$)\text{'})$;

ylabel$(\text{'}$Symbol Error Rate $($SER$)\text{'})$;

title$(\text{'}$SER vs$.$ Eb$/$N for MPSK and MFSK$\text{'})$;

legend$(\text{'}$MPSK Theory', $\text{'}$MFSK Theory', $\text{'}$M$=2$ Simulation', $\text{'}$M$=4$ Simulation', $\text{'}$M$=8$ Simulation'$)$;

grid on;

$\%$ Compare results

disp$(\text{'}$Observations:$\text{'})$;

for m $=1$:length$($M$)$

disp$([\text{'}$For M$=\text{'},$ num$2$str$($M$($m$)),\text{'}$:$\text{'}])$;

disp$([\text{'}-$ Simulated SER generally agrees with theoretical SER for high Eb$/$N$.\text{'}])$;

disp$([\text{'}-$ At low Eb$/$N$,$ simulated SER may deviate slightly due to simulation limitations$.\text{'}])$;

end

Arrays have incompatible sizes for this operation.

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