خطا در شبیه سازی ofdm با متلب

[sepidar1996]

با سلام من تازه کارم با متلب قصد شبیه سازی رو داشتم. اینم مقاله ای که قصد شبیه سازیش رو داشتم:

DEPARTMENT OF APPLIED ELECTRONICS AND TELECOMMUNICATION

ولی با اررو زیر مواجه شدم لطفا راهنمایی بفرمایید باتشکر.

	 function y=mapping (x) | Error: Function definitions are not permitted in this context.
	
	 function y=mapping (x)
	% it is symbol mapping for QPSK mapping
	%x = input signal of data (size ۱xN complex)
	%y = output signal of data (size ۱xN complex)
	% in this part, we will do splitting data into real and imaginary part rex = real (x);
	% real part of the signal (splitting data into real part)
	% letter a in the block diagram above is representing this part
	imx = imag (x);
	% imaginary part of the signal (splitting data into imaginary part)
	% letter b in the block diagram above is representing this part
	rey = quantiz (rex, [۰]);
	% it is for dividing axis into two parts due to ۴ QPSK
	imy = quantiz (imx, [۰]);
	% it is for dividing axis into two parts due to ۴ QPSK
	rey = ((rey .* ۲) -۱) .* sqrt (۲);
	imy = ((imy .* ۲) -۱) .* sqrt (۲); y = rey + j.*imy;
	%Just to summarize shortly what has been done in this part is dividing complex plain into ۴ regions and every region is represented by defined point which is ideal point (refer Figure ۶)
	%%%
	function error = compare (correct, received)
	% in this function, it is comparing correct signal with received signal
	e =(correct ~= received) ;
	% this part is when error is not equal to received signal
	error = sum (e) ;
	% it is sum of errors
	%%%
	function ser = structure (snr)
	% it is the main function
	n = ۱۲۸ ;
	% it is the block size of OFDM for this simulation
	%snr = ۱۰ ; m = ۱۰;
	% it is averaging ser = ۰ ;
	for ii=۱:m
	a = rand (۱,n);
	% it is generating random data into real part of the signal
	b = rand (۱,n);
	% it is generating random data into imaginary part of the signal
	a = ((a .* ۲) - ۱);
	% it is making bipolar signal to unipolar signal
	b = ((b .* ۲) - ۱);
	% it is making bipolar signal to unipolar signal
	c = a + j .* b ;
	% it is making complex signal
	d = mapping (c) ;
	% it is transmitted signal before IFFT (QPSK mapping)
	e = ifft (d,n) ;
	% it is OFDM Modulation
	f = awgn (e, snr) ;
	% it is additive noise which was added here
	g = fft( f,n);
	% it is OFDM Demodulation
	h = mapping (g);
	% it is signal after QPSK de-mapping
	ser = ser + compare (h,d);
	% it is comparing signal h (Signal after QPSK de-mapping) to signal d
	%(Transmitted signal before IFFT) end
	ser = ser ./ m;
	% it is division in averaging
	ser = ser ./ n;
	% it is division in by number of subcarriers
	%%%
	function loop
	% This is the looping function. This function is used for looping in the simulation.
	ii=۱;
	for snr = ۰:۵:۵۰
	% it is sweeping over snr values
	SER (ii) = structure (snr); SNR (ii) = snr ;
	ii = ii + ۱;
	end
	semilogy (SNR, SER)
	% it is y axis values from ۰ to ۱
	xlabel(&#۳۹;SNR in dB&#۳۹;
	% it is labeling x axis
	ylabel(&#۳۹;SER&#۳۹;
	% it is labeling y axis
	% end of coding
	%%%