Regional Information Meeting and Workshop relatedto the RRC06 for the administrations of the African

1
Regional Information Meeting and Workshop
related to the RRC-06 for the administrations of
the African countriesDakar, Senegal, 25-29 April
2005

• RRC Propagation Information
• Field strength prediction method

Pham Nhu Hai Radiocommunication Bureau
2
Outline

• Overview propagation models
• RRC propagation curves/tables
• RRC propagation zones
• Propagation prediction method
• Propagation for other services

3
Propagation models

• Path specific
• Terrain data
• Time consuming
• Accurate but no agreed methods for broadcasting
• Path general
• General terrain data required (effective heights)
• Fast easy to use
• ITU conference (ITU-R P 370, 529, 1146 and 1546)

4
One propagation model!

• ITU-R P.1546 replaces
• ITU-R P.370 (BC VHF/UHF)
• ITU-R P.529 (LM VHF/UHF)
• ITU-R P.1146 (LM BC, 1-3 GHz)
• Path general methods
• 30 MHz 3000 MHz
• 1 km 1000 km
• 1 - 50 percentage of time

5
RRC propagation model

• Set of propagation curves/tables of field
  strength (dBu) vs distance (km)
• Heights of transmitting/base antenna
• 100, 600 and 2000 MHz
• 1, 10 and 50
• Receiving antenna height of 10m in open area
• Detailed inter/extrapolation procedures
• Other percentage of time
• Other frequencies
• Other transmitting/base antenna heights

6
RRC propagation zones
7
600 MHz, 50 Land temperate
8
600 MHz, 1 Land temperate
9
600 MHz, 1 warm seas
10
Propagation prediction method

• Maximum field strength values
• Determine transmitting/base antenna height
• Interpolation of field strength as a function of
• Transmitting/base height h1
• Distance
• Frequency
• Percentage of time

11
Propagation prediction method (2)

• Mixed paths
• Correction for receiving/mobile antenna height
• Correction of terrain clearance angle
• Location variability in land area-coverage
  prediction
• FS prediction in 16 easy steps!!!!

12
Transmitting/base antenna height h1

• Land paths gt 15 km
• h1 heff (height over average terrain 3-15 km)
• Land paths lt 15 km
• h1 ha (height of the mast) for dlt3km
• h1 ha (heff-ha)(d-3)/12 for 3 ltdlt15 km
• Sea paths
• h1 heff for h1 gt1 m

13
Field strength for a height h1

• h1 ltgt 10, 20, 75,.., 1200 m
• h1 in the range 10 3000 m
• E Einf
• (Esup-Einf)log(h1/hinf)/log(hsup/hinf)
• hinf 600 if h1gt 1200
• hsup 1200 if h1gt 1200
• h1 in the range 0 10 m
• Negative h1 (terrain clearance angle)

14
Field strength f (distance)

• If d does not coincide with one of the tabulation
  distances
• E Einf
• (Esup-Einf)log(d/dinf)/log(dsup/dinf)

15
Field strength f (frequency)

• If freq does not coincide with one of the nominal
  values (100, 600)
• E Einf
• (Esup-Einf)log(f/finf)/log(fsup/finf)

16
Mixed path consideration

• ITU-R P.370
• Based on percentage of land and sea path
• Shows unrealistic recovery effect
• Sea curves show large variation wrt effective
  heights

• RRC (P.1546)
• Longest contiguous path is important (breaking
  down ducting)
• Avoid recovery effect
• Consistent set of sea curves

17
FS prediction in 16 easy steps!!!
18
Conclusions

• One propagation model
• Based on ITU-R P.1546
• Data available in curves and tables
• Better prediction for sea paths
• Step-by-step FS prediction method
• TGFC..