Hi!
I read the code of tinyos-2.x/tos/lib/tossim/CpmModelC.nc, and find that there
is a formula to estimate prr from snr:
PRR=(1-0.5*erfc(\beta_1*\sqrt{\frac{|10^{SINR(dB)/10}-\beta_2|}{2}}))^{23*2}
where $\beta_1$ and $\beta_2$ are 1.3687 and 0.9187.
I want to know how to get this formula. Is it deduced from some classic
formula?
Any help is appreciated.
Following is the code:
double prr_estimate_from_snr(double SNR) {
double beta1 = 1.3687;
double beta2 = 0.9187;
double SNR_lin = pow(10.0, SNR/10.0);
double X = fabs(SNR_lin-beta2);
double PSE = 0.5*erfc(beta1*sqrt(X/2));
double prr_hat = pow(1-PSE, 23*2);
dbg("CpmModelC,SNR", "SNR is %lf, PRR is %lf\n", SNR, prr_hat);
if (prr_hat > 1)
prr_hat = 1;
else if (prr_hat < 0)
prr_hat = 0;
return prr_hat;
Regards,
Shucheng
2009-12-22
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