thank you very much ..!!!
i have one more question ...
so suppose we have
As -amplitude of signal
An- amplitude of noise
what power of signal we have if we use o modulation 16 psk ??
SNR=10log(As/An)^2 // As=1
SNR=10log(1/An)^2
An=sqrt(pow(10,(-SNR/10))
in program which i found in google we have simulation awgn channel but i dont understand some formula
void awgn()
{
/* Add AWGN to transmitted sequence */
double u1,u2,s,noise,randmum;
int i;
#ifdef PRINT
printf("Received = ");
#endif
#ifdef NO_NOISE
received_I = psk_I[transmitted];
received_Q = psk_Q[transmitted];
return;
}
#else
do
{
randmum = (double)(random())/MAX_RANDOM;
u1 = randmum*2.0 - 1.0;
randmum = (double)(random())/MAX_RANDOM;
u2 = randmum*2.0 - 1.0;
s = u1*u1 + u2*u2;
} while( s >= 1);
noise = u1 * sqrt( (-2.0*log(s))/s )/amp;
//************************************************
RATE = (2.0 / (double) n2)*3.0; // 2 bits per symbol if encoder is rate 1/2
what is this n2 and why we calculate rate using this formula ?? and why that fomula ...??
amp = sqrt(2.0*RATE*pow(10.0,(snr/10.0)));
what is this (2.0*Rate) ???????
if i have encoder is rate 2/3 so how i can calculate amp=???????
thank You
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if somebody lokk some infomartion about trelllis coding i have good website from university of technology in Poznan Poland
http://www.invocom.et.put.poznan.pl/~invocom/C/P1-7/en/P1-7/p1-7_6_7.htm