I have two loops, how can i get rid of the inner loop "for j=1:nSym"?

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Ray
Ray 2016-4-1
评论： Ray 2016-4-6
for i=1:length(EsN0dB),
for j=1:nSym
%
%-----------------Transmitter--------------------
%---Generating a uniformly distributed random numbers in the set
%[0,1,2,..,M-1] i.e from [0 to 15]
info = ceil(M.*rand(1,Ntot))-1; % the reason we subtract '1' is because we want to go from '0' to '15 instead of
% '1' to '16'.
%
% 16QAM constellation maping
x=RefPoint(info+1); % The reason we add 1 to info is because the array must be positive and since we have a '0'in info, we need add '1'.
%
%--- Reference Constellation for demodulation and Error rate computation--
refI = real(RefPoint);
refQ = imag(RefPoint);
%
%--------------Channel Modeling ----------------
%Adding noise with variance according to the required Es/N0
Esym=sum(abs(ofdm_signal).^2)/(length(ofdm_signal)); %Calculate actual symbol energy from generated samples
N0=Esym/(10.^(EsN0dB(i)/10)); %Find the noise spectral density
noiseSigma = sqrt(N0/2); %Standard deviation for AWGN Noise
n = noiseSigma*(randn(1,length(ofdm_signal))+1i*randn(1,length(ofdm_signal))); %Add noise in IQ plane.
%noise=1/sqrt(2)*(randn(1,length(ofdm_signal))+1i*randn(1,length(ofdm_signal)));
%r= sqrt((N+Ncp)/N)*ofdm_signal + n;
r= ofdm_signal + n;
%
%-----------------Receiver----------------------
%Removing cyclic prefix
r_Parallel=r(Ncp+1:(N+Ncp));
%
%FFT Block
r_Time=1/sqrt(N)*(fft(r_Parallel,N));
%Extracting the data carriers from the FFT output
R_Freq=r_Time([(2:Ntot/2+1) (Ntot/2+13:Ntot+12)]);
%
% %-------------I-Q Branching---------------
r_i = real(R_Freq);
r_q = imag(R_Freq);
%
%Detection in the receiver - Euclidean distance Method
[estimatedTxSymbols,dcap]= iqOptDetector(R_Freq,RefPoint);
%
numErrors = sum((info~=dcap-1)); %Count number of errors
%Accumulate bit errors for all symbols transmitted
errors(i)=errors(i)+numErrors;
end
end

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采纳的回答

Walter Roberson
Walter Roberson 2016-4-6
The line
Esym=sum(abs(ofdm_signal).^2)/(length(ofdm_signal)); %Calculate actual symbol energy from generated samples
does not depend upon i or j or upon any data that is being changed in the nested loops. Move that line to before both loops.
The line
N0=Esym/(10.^(EsN0dB(i)/10)); %Find the noise spectral density
does not depend upon j, so it can be moved to before the "for j" loop. It could be further vetorized to
all_N0 = Esym/(10.^(EsN0dB/10)); %Find the noise spectral density
and then in the "for i" loop,
N0 = all_N0(i);
However, N0 is only used in
noiseSigma = sqrt(N0/2); %Standard deviation for AWGN Noise
so instead that could be vectorized,
all_noiseSigma = sqrt(all_N0/2);
and then inside the the "for i" loop,
noiseSigma = all_noiseSigma(i);
... and so on. Keep picking at the code and finding places that do not change inside a loop and move those to before the loop. Places where you operate on one element at a time, move to before the loop and operate on as a vector and then (if necessary) index the vector result inside the loop.

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