Reply by deut...@yahoo.com●February 25, 20082008-02-25
Your answer is right, I need to normalize the energie of the Rayleigh Channel to
1. Thanks for all the answers.
Kenny
Reply by Nandan Das●February 15, 20082008-02-15
I think what it means is that your average channel power (averaged over the
fading statistics) is not 1.
Nandan
On Thu, Feb 14, 2008 at 4:46 AM, loc truong wrote:
>
> but when I simulate for Rayleigh Fading channel , with the same Noise, I
> need to scale the 4QAM symbols with factor 1/sqrt(2), then it works.
>
> thanks,
>
> Kenny
>
Reply by loc truong●February 14, 20082008-02-14
hello,
thanks for all your responses,
the white noise I did as below
sigma = sqrt(1/(2*Eb_No_linear));
AWGN_Noise = sigma.*(randn(1,N)+j*randn(1,N));
but when I simulate for Rayleigh Fading channel , with the same Noise, I need to
scale the 4QAM symbols with factor 1/sqrt(2), then it works.
thanks,
Kenny
Reply by Nandan Das●February 14, 20082008-02-14
My guess is that your noise power is off by the same factor of 1/sqrt(2).
Check how you generate complex noise and that each of the real and imaginary
part should have noise variance half of the total noise power.
Nandan
On Feb 13, 2008 6:10 AM, loc truong wrote:
> hi everyone,
>
> I am trying to simulate a OFDM system with AWGN channel, 4QAM symbol in
> matlab.
> Theoritically, the curve for BER should be the same as for BPSK
>
> BER = Q(sqrt(2*Eb/No));
>
> But I have a problem: When I normalized the symbols 1/sqrt(2)(1+j) (For
> example), that doesn't work. But when I leave out the factor 1/sqrt(r),
it
> works perfectly. Anybody knows the answer? Please help.
>
> Thank you very much
>
> Kenny
>
Reply by loc truong●February 13, 20082008-02-13
hi everyone,
I am trying to simulate a OFDM system with AWGN channel, 4QAM symbol in
matlab.
Theoritically, the curve for BER should be the same as for BPSK
BER = Q(sqrt(2*Eb/No));
But I have a problem: When I normalized the symbols 1/sqrt(2)(1+j) (For
example), that doesn't work. But when I leave out the factor 1/sqrt(r), it
works perfectly. Anybody knows the answer? Please help.