taking frequency fourier transform (FFT) for the LTE NB-IOT NPRACH frequency hopping repetations

tis is the time domain CPs and SYMBOLS in the frequnecy hopping. i have written a code to remove the cyclic prefix and take only the symbol sample to an array. i will put code below, can anyone check the code and give an update the mistakes becasue i receive error like exceeding the error size when increasing the repetations. here is the code ,

%% FREQUENCY FOURIER TRANSFORM

cp0 = 128;% assign the cyclic prefix sample value of format 0 to cp0

size = 512;%assign the symbol sample value for size

m = cp0;%assign cp0 to m

y = 1;

x = 1;

for repeatation_x = 1:1% set for loop for two repetations

for symbol_group = 1:4% set for loop for 4 symbol group in one repetation

ara(1:size,y) = waveform(m+1:m+size);% get a first symbol samples to ara matrix

for last_four_symbol = 1:4% set for loop to get the samples of other all 4 symbols

y = y+1;

x = x+1;

ara(1:size,y) = waveform(m+(x-1)*size +1:m+x*size);

end

m = m+y*size+cp0;

y = y+1;

end

end