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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
// use call with log/ln as this may be faster
// use constant of value 20.0/log(10.0)
static __inline float _20log10f(float x)
{
return(8.685889f*logf(x));
}
double SUIpathLoss(double f, double TxH, double RxH, double d, int mode)
{
/*
f = Frequency (MHz) 1900 to 11000
TxH = Transmitter height (m)
RxH = Receiver height (m)
d = distance (km)
mode A1 = URBAN / OBSTRUCTED
mode B2 = SUBURBAN / PARTIALLY OBSTRUCTED
mode C3 = RURAL / OPEN
http://www.cl.cam.ac.uk/research/dtg/lce-pub/public/vsa23/VTC05_Empirical.pdf
*/
d *= 1e3; // km to m
// Urban (A1) is default
float a = 4.6;
float b = 0.0075;
float c = 12.6;
float s = 10.6; // Optional fading value. Max 10.6dB
float XhCF = -10.8;
if (mode == 2) { // Suburban
a = 4.0;
b = 0.0065;
c = 17.1;
XhCF = -10.8;
}
if (mode == 3) { // Rural
a = 3.6;
b = 0.005;
c = 20;
XhCF = -20;
}
float d0 = 100.0;
float A = _20log10f((4 * M_PI * d0) / (300.0 / f));
float y = a - (b * TxH) + (c / TxH);
//Correction factors
float Xf = 6.0 * log10(f / 2000.0);
float Xh = XhCF * log10(RxH / 2000.0);
Xh *=-1;
//fprintf(stdout,"A %lf y %lf Xf %lf Xh %lf\n",A,y,Xf,Xh);
return A + (10 * y * log10(d / d0)) + Xf + Xh + s;
}