CCDF_OFDMA.m

function CCDF=CCDF_OFDMA(N,Nos,b,dBs,Nblk)
% CCDF of OFDM signal with no PAPR reduction technique.
% N    : Number of total subcarriers (256 by default)
% Nos  : Oversampling factor (4 by default)
% b    : Number of bits per QAM symbol
% dBs  : dB vector
% Nblk : Number of OFDM blocks for nblkation

%MIMO-OFDM Wireless Communications with MATLAB¢ç   Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang
%2010 John Wiley & Sons (Asia) Pte Ltd

dBcs = dBs + (dBs(2)-dBs(1))/2; % dB midpoint vector
NNos = N*Nos; 
M=2^b; Es=1; A=sqrt(3/2/(M-1)*Es); % Normalization factor for M-QAM
mod_object=modem.qammod('M',M,'SymbolOrder','gray'); 
for nblk=1:Nblk
   mod_sym = A*modulate(mod_object,randint(1,N,M));
   [Nr,Nc]=size(mod_sym);
   zero_pad_sym=zeros(Nr,Nc*Nos);
   for k=1:Nr          % zero padding for oversampling
      zero_pad_sym(k,1:Nos:Nc*Nos)=mod_sym(k,:);
   end
   ifft_sym=ifft(zero_pad_sym,NNos);
   sym_pow=abs(ifft_sym).^2;
   mean_pow(nblk)=mean(sym_pow); max_pow(nblk)=max(sym_pow); 
end
PAPR=max_pow./mean_pow;  PAPRdB=10*log10(PAPR); % measure PAPR
dBcs = dBs + (dBs(2)-dBs(1))/2;   % dB midpoint vector
count = 0;  N_bins = hist(PAPRdB,dBcs);
for i=length(dBs):-1:1
   count = count+N_bins(i); CCDF(i) = count/Nblk;
end