Re: Minimum SNR required
Hi,
I have a reference on te SNR requrement for different BER requirements for different modulation scheme. a page of 'Degrees of freedom in adaptive modulation' by A. Goldsmith is attached
I have a different issue on this area, I follow the equations as given in the paper, but the graph that i get is not the same ( i calculated for 16-QAM)
Here is the code i run in MATLAB:
k=4; % 4bits/symbol M=2^k >> 16QAM
SNR=[1:1000];SNRdb=10*log(SNR); % SNR/bit
BER4=0.2*exp(-1.6*SNR/(2^k-1));
ber=2*(1-1/sqrt(2^k))/k*erfc(sqrt(1.5*SNR/(2^k-1)));
figure(2);
semilogy(SNRdb,BER4);hold on;
semilogy(SNRdb,ber,'r*');grid on; axis([0 50 10^-8 1]);
Can anyone help me with this equation, i just don't know why they are not consistent...
Thank you