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