Versions Compared

Version Old Version 6 New Version Current
Changes made by

Former user

Zeljko Tabakovic

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

Anchor
A17.87.3
A17.87.3
For calculation of the path loss according to Recommendation ITU-R P.1546-1 Annex 8 the following procedure is followed:

...

    • Time percentage :                           1% £<= pt <=  50 pt £< 50 %
    • Frequency :                                     30 MHz £<= f £<= 3 3 000 MHz
    • Distance :                                        0.001 km  £<= d <= 1000 d £< 1000 km
    • Transmitter antenna height :            0 m £<= ht <= 3000 ht £< 3000 m
    • Receiver antenna height :               1 m £<= hr <= 3000 m hr £< 3000 m

 

2 Determination of lower and higher nominal percentages ptinf and ptsup:

...

4.1.1) Calculate the dimensionless parameter k, function of the required transmitter height, ht:

             Image RemovedImage Added                                 (Eq. 227218)

4.1.2) Determine from the following table the set of parameters a0 to a3, b0 to b7, c0 to c6 and d0 to d1 to be used according to nominal values of frequencies and time percentages:

 

Anchor
T087T085T087
T085
Table 8785: Parameters a0 to a3, b0 to b7, c0 to c6 and d0 to d1

 

Frequency

100 MHz

600 MHz

2 000 MHz

pt %

50

10

1

50

10

1

50

10

1

a0

0.0814

0.0814

0.0776

0.0946

0.0913

0.0870

0.0946

0.0941

0.0918

a1

0.761

0.761

0.726

0.8849

0.8539

0.8141

0.8849

0.8805

0.8584

a2

-30.444

-30.444

-29.028

-35.399

-34.160

-32.567

-35.399

-35.222

-34.337

a3

90.226

90.226

90.226

92.778

92.778

92.778

94.493

94.493

94.493

b0

33.6238

40.4554

45.577

51.6386

35.3453

36.8836

30.0051

25.0641

31.3878

b1

10.8917

12.8206

14.6752

10.9877

15.7595

13.8843

15.4202

22.1011

15.6683

b2

2.3311

2.2048

2.2333

2.2113

2.2252

2.3469

2.2978

2.3183

2.3941

b3

0.4427

0.4761

0.5439

0.5384

0.5285

0.5246

0.4971

0.5636

0.5633

b4

1.256E-7

7.788E-7

1.050E-6

4.323E-6

1.704E-7

5.169E-7

1.677E-7

3.126E-8

1.439E-7

b5

1.775

1.68

1.65

1.52

1.76

1.69

1.762

1.86

1.77

b6

49.39

41.78

38.02

49.52

49.06

46.5

55.21

54.39

49.18

b7

103.01

94.3

91.77

97.28

98.93

101.59

101.89

101.39

100.39

c0

5.4419

5.4877

4.7697

6.4701

5.8636

4.7453

6.9657

6.5809

6.0398

c1

3.7364

2.4673

2.7487

2.9820

3.0122

2.9581

3.6532

3.547

2.5951

c2

1.9457

1.7566

1.6797

1.7604

1.7335

1.9286

1.7658

1.7750

1.9153

c3

1.845

1.9104

1.8793

1.7508

1.7452

1.7378

1.6268

1.7321

1.6542

c4

415.91

510.08

343.24

198.33

216.91

247.68

114.39

219.54

186.67

c5

0.1128

0.1622

0.2642

0.1432

0.1690

0.1842

0.1309

0.1704

0.1019

c6

2.3538

2.1963

1.9549

2.2690

2.1985

2.0873

2.3286

2.1977

2.3954

d0

10

5.5

3

5

5

8

8

8

8

d1

-1

1

2

1.2

1.2

0

0

0

0

 

 

4.1.3) Calculate the unblended to maximum value field strength, Eu, at the distance, d, and transmitting height, ht, as follows:

                                                                           Image RemovedImage Added             (Eq. 228219)

where: Image RemovedImage Added

and: Image RemovedImage Added

and: Image RemovedImage Added

where: Image Added

 

...

where: Image Added

 

...

and: Image Added

 

...

4.1.4) Calculate the blended to the free space value of field strength, Eb, at the distance, d, and transmitting height, ht, as follows:

                                                                               Image RemovedImage Added     (Eq. 229220)

where:

Efs is the free-space field strength

...

                             E = Einf + (Esup - Einf) log(f/finf)/log(fsup/finf)     (dB(μV/m))                                  (Eq. 230221)

where:

Einf:       E(f= finf , d, ht, hr, ptinf)

Esup:      E(f= fsup , d, ht, hr, ptinf)

 

4.3) Dual calculation for the field strength E(f, d, ht, hr, ptsup) using log-linear interpolation in frequency range:

                             E = Einf + (Esup - Einf) log(f/finf)/log(fsup/finf)     (dB(μV/m))                                  (Eq. 231222)

where:

Einf:                       E(f= finf , d, ht, hr, ptsup)

...

                  E = Esup (Qinf- Qt)/(Qinf- Qsup) + Einf(Qt - Qsup)/(Qinf- Qsup)     (dB(μV/m))                 (Eq. 232223)     

Where: (Qi (x) being the inverse complementary cumulative normal distribution function):

...

Esup     =E(f, d, ht, hr, ptsup)

 

5 For a transmitting/base antenna height ht less than 10 m, determine the field strength for the required height and distance using following method

...

If in the latter equation dH(10) + d - dH(ht) exceeds 1 000 km, even though d <- £ 1 000 km, E10 may be found from linear extrapolation for log(distance) of the curve, given by:

 

E10  =    Einf + (Esup - Einf) log(d/Dinf)/log(Dsup/Dinf)                        dB(µV/m)                                          

...

Note: this recommendation is not valid for distances greater than 1 000 km. This method should be used only for extrapolating for ht < 10 m.

 

6 If the receiving antenna height hr is not equal to the height of representative clutter at its location (denoted R), correct the field strength as follows:

...

SEAMCAT always assumes the height of local clutter R , depending on the propagation environment set in the model selection window:

Anchor
T088T086T088
T086
Table 86: Default clutter height in the ITU-R P1546-1 model (when clutter height option not activated)

 

Selected environment

Assumed height of local clutter, m

Rural

10

Sub-urban

10

Urban

20

 

 

If the receiving antenna height, hr (m), is different from the assumed R value, as shown in Table 86 , a correction shall be added to the field strength taken from the curve.

 

Where the receiving antenna is adjacent to land account should first be taken of the elevation angle of the arriving ray by calculating a modified representative clutter height R' (m), given by:

R'            =    R    (m)                                            for ht <= 6.5d + R                                     (Eq. 233224)

               = (1 000 d R – 15 ht)/(1 000 d - 15 ) (m) for ht > 6.5d + R                                      (Eq. 234225)

where ht is in metres and distance d is in km.

 

The value of R' must be limited if necessary such that it is not less than 1 m.

 

When the receiving antenna is in an urban environment the correction is then given by:

         Correction = (6.03) - J(n)                      dB                   for                                                dB                   for hr < R

= K hr log(hr /R')                                             dB                   for hr ³ R                 (Eq. 235226)

where J(n) is given by :

              Image RemovedImage Added                             (Eq. 236227)

where:

           n                      =                          Knu Ö (hdif qclut) - PLS. INSERT CORRECT FORMULA AND SYMBOL

           hdif                    =                            R' - hr         (m)

...

Correction         = 0.0                                         dB        d ←  £ d (hr)                                   (Eq. 237228)

                                    = (C10) log(d/dhr)/log(d10/dhr)         dB        dhr < d < d10              

...

dhr:       distance at which the path just has 0.6 Fresnel clearance for the required value of hr calculated as D06(f, ht, hr) as given in note 2

 

This recommendation is not valid for receiving antenna heights, hr, less than 1 m.

 

7 Add a log-normal term G(sL) corresponding to the variability in the percentage of locations :

...

                               sL = K + 1.6 log(f)          dB                                                               (Eq. 238229)

where :

K          =          2.1 - for mobile systems in urban locations;

...

                               Efs = 106.9 - 20 log(d)     (dB(mV/m))                                       (Eq. 239230)

9 Convert field strength to path loss using following formula:

...

             Lb = 77.2 – E 20 log f     (dB)                                                  (Eq. 240231)

where:

Lb: basic transmission loss (dB)

E: field strength in dB(mV/m) measured with a transmitting power of 1 W e.i.r.p.

f: frequency (MHz).

 

Note 1: The following approximation to the inverse complementary cumulative normal distribution function, Qi(x), is valid for 0.01 <= x <= 0.99 :

...

                                                 Image RemovedImage Added

Image RemovedImage Added

            

                                                                       C0 = 2.515517

...

                                                                                                                             Image RemovedImage Added

where:                      Df:         Image Removed           (km)     (frequency

                      Df:        frequency-dependent term

...

                                                                              

...

                     =           Image Added               km                                                                              

                     Dh:        asymptotic term defined by horizon distances)

                                                                                           

...

=        Image Added                       km                                                                              

                        f:        frequency (MHz)

...