please describe this loop

for i=1 : length(SNR_V) SNR=SNR_V(i); for k=1 : nIteration % generating random channel coefficients h(1:L,1)=random('Normal',0,1,L,1) + ... j * random('Normal',0,1,L,1); h=h./sum(abs(h)); % normalization

% Tr Data TrDataBit=randint(N,1,M); TrDataMod=qammod(TrDataBit,M); TrDataMod(Ip)=Ep * TrDataMod(Ip); TrDataIfft=ifft(TrDataMod,N); TrDataIfftGi=[TrDataIfft(N- GI + 1 : N);TrDataIfft];

% tx Data TxDataIfftGi=filter(h,1,TrDataIfftGi); % channel effect % adding awgn noise TxDataIfftGiNoise=awgn(TxDataIfftGi, SNR - db(std(TxDataIfftGi))); % normalization to signal power db

TxDataIfft=TxDataIfftGiNoise(GI+1:N+GI); TxDataMod=fft(TxDataIfft,N);

% Channel estimation Spilot=TrDataMod(Ip); % trnasmitted pilots Ypilot=TxDataMod(Ip); % received pilots

G=(Ep * length(Ip))^-1* ctranspose(sqrt(Ep)*diag(Spilot)*ctranspose(F(1:L, Ip)));%ctranspose(F(1:L, Ip))=(F(1:L, Ip))'

hHat=G*Ypilot; % estimated channel coefficient in time domain

TxDataBit=qamdemod(TxDataMod./(fft(hHat,N)),M);

% bit error rate computation [nErr bErr(i,k)]=symerr(TxDataBit(Is),TrDataBit(Is)); end end