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Coverage Coverage Planning Planning


Module objectives

DEFINE COVERAGE THRESHOLD

DESCRIBE DIFFERENT COVERAGE PLANNING MARGINS

LOCATION PROBABILITYPENETRATION LOSS

CALCULATE COVERAGE AREAS

At the end of this module you will be able to …


Content of Coverage Planning

COVERAGE THRESHOLD

COVERAGE AREA


Coverage Planning

COVERAGE THRESHOLD

COVERAGE AREA


Coverage ThresholdBasics

• Based on the calculated maximum allowed path loss in PBGT, the coverage threshold can be defined

• Coverage threshold depends on margins related to

• Location probability (= slow fading)

• Fast fading / Interference degradation

• Polarization / Antenna orientation loss

• Body loss

• Penetration losses (vehicle or building)


“Real” maximum allowed path loss

Coverage ThresholdDL Calculation Process

function (location probability)

From power budget calculations

function (morphological area)

Okumura-Hata

function (morphological area)

= Maximum allowed path loss => Coverage threshold⇓

Cell radius

⇓Cell area

EIRP -

Minimum allowed receiving level –

Slow fading and other margins –

Building penetration loss


Full coverage of an area can never be guaranteed!

Coverage ThresholdLocation Probability

• Outages• due to coverage gaps Pno_cov

• due to interferences Pif

• Total location probability in a cell (1- Pno_cov) * (1- Pif)

• Both time and location probability

• Typical required values are 90-95%


• When calculating cell radius, LP is 50% by the cell edge and ~75% over the cell area

• To get 90% LP, the cell radius has to be reduced

Coverage ThresholdSlow Fading Margin

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1-3 -2 -1 0 1 2 3

σ σ

90% of the area

Slow fading margin


• ETSI specific margin

Power budget

GENERAL INFORMATIONFrequency (MHz): 1800 System: DCS1800Case description: MS Class: 1

RECEIVING END: BS MSRX RF- Input Sensitivity dBm -108.00 -100.00 AInterference Degradation Margin dB 3.00 3.00 BBody Proximity Loss dB 0.00 2.00 CCable Loss + Connectors dB 3.00 0.00 DRx Antenna Gain dBi 18.00 0.00 EDiversity Gain dB 4.00 0.00 FIsotropic Power dBm -124.00 -95.00 G=A+B+C+D-E-FField Strength dBµV/m 18.31 47.31 H=G+Z*TRANSMITTING END: MS BSTX RF Output Peak Power W 1.00 29.50(mean power over RF cycle) dBm 30.00 44.70 KBody Proximity Loss dB 2.00 0.00 LIsolator + Combiner + Filter dB 0.00 2.20 MRF-Peak Power, Combiner Output dBm 28.00 42.50 N=K-L-MCable Loss + Connectors dB 0.00 3.00 OTX Antenna Gain dBi 0.00 18.00 PPeak EIRP W 0.63 562.11(EIRP = ERP + 2dB) dBm 28.00 57.50 Q=N-O+P

* Z = 77.2 + 20*log(freq[MHz])

BT99 - AFE with combiner bypass (equiv. to

Coverage ThresholdInterference Degrade Margin


Coverage ThresholdPolarisation / Antenna Orientation Loss

• Polarisation or antenna orientation losses depend on the orientation of the mobile antenna (vertical-horisontal)

• Typical loss 5-10 dB due to mismatch of polarisation

• Sometime taken into account but not always


Coverage ThresholdBody Loss

• Body loss happens because of the existence of the human body

• Typical loss 5-10 dB depending on the distance between mobile and human body

• Typically taken into account in coverage threshold


Coverage ThresholdPenetration Loss

• Penetration losses have to be added as mean value, and standard deviation need to be taken into account as well

• type mean sigma

• urban building 15 dB 7 dB• suburban 10 dB 7 dB• in-car 8 dB 5 dB


Coverage Planning

COVERAGE THRESHOLD

COVERAGE AREA


COMMON INFO DU U SU F OMS antenna height (m): 1,5 1,5 1,5 1,5 1,5BS antenna height (m): 30,0 30,0 30,0 45,0 45,0Standard Deviation (dB): 7,0 7,0 7,0 7,0 7,0BPL Average (dB): 15,0 12,0 10,0 6,0 6,0Standard Deviation indoors (dB): 10,0 10,0 10,0 10,0 10,0OKUMURA-HATA (OH) DU U SU F OArea Type Correction (dB) 0,0 -4,0 -6,0 -10,0 -15,0WALFISH-IKEGAMI (WI) DU U SU F ORoads width (m): 30,0 30,0 30,0 30,0 30,0Road orientation angle (degrees): 90,0 90,0 90,0 90,0 90,0Building separation (m): 40,0 40,0 40,0 40,0 40,0Buildings average height (m): 30,0 30,0 30,0 30,0 30,0INDOOR COVERAGE DU U SU F OPropagation Model OH OH OH OH OHSlow Fading Margin + BPL (dB): 22,8 19,8 17,8 13,8 13,8Coverage Threshold (dBµV/m): 59,1 56,1 54,1 50,1 50,1Coverage Threshold (dBm): -77,2 -80,2 -82,2 -86,2 -86,2Location Probability over Cell Area(L%): 90,0% 90,0% 90,0% 90,0% 90,0%

Cell Range (km): 1,33 2,10 2,72 5,70 7,99OUTDOOR COVERAGE DU U SU F OPropagation Model OH OH OH OH OHSlow Fading Margin (dB): 4,5 4,5 4,5 4,5 4,5Coverage Threshold (dBµV/m): 40,8 40,8 40,8 40,8 40,8Coverage Threshold (dBm): -95,5 -95,5 -95,5 -95,5 -95,5Location Probability over Cell Area(L%): 90,0% 90,0% 90,0% 90,0% 90,0%

Cell Range (km): 4,39 5,70 6,50 10,69 14,99

Coverage AreaCell range: Example of Dimensioning (EXCEL based calculation)


• After cell radius has been determined, cell area can be calculated

• When calculating cell area, traditional hexagonal model is taken into account

R

OmniA = 2,6 R1

2Bi-sectorA= 1,73 R2

2Tri-sector

A = 1,95 R32

R

R

Coverage AreaCoverage Area in Dimensioning


• Three hexagons • Three cells

Coverage AreaHexagons vs. Cells


Coverage AreaExample of Planning Tool Calculation


Coverage AreaCell Area Terms

• Dominance area

• Service area

• Coverage area

6dB hysteresis margin

coverage limit

cell coverage range

cell service range

dominance range


Coverage AreaEnhancement

• Improving link budget• Sensitivity• Power• Antennas

• Reducing the effect of geography• BTS antenna heights• Good network plan

• Technical solutions for improving link budget• Combiner by-pass• Mast head preamplifier• Booster


Coverage AreaConclusion

• Achievable cell size depends on• Frequency band used (450, 900, 1800 MHz)• Surroundings, environment• Link budget figures• Antenna types• Antenna positioning• Minimum required signal levels


Exercises / Questions

List the margins needed for the coverage planning threshold!

Define the outdoor planning threshold for the GSM1800 network when STD = 9 dB and the required outdoor area location probability = 95 %.

Calculate slow fading margin for 95% probability when STD = 7, 8, 10 (Excel exercise, OPTIONAL).


References

1. W.C.Y. Lee, “Mobile Communications Design Fundamentals,” John Wiley & Sons, 1993.

2. W.C.Y. Lee, “Mobile Cellular Telecommunication Systems,” McGraw-Hill Book Company, 1990.

3. W.C. Jakes, Jr., (ed.), “Microwave Mobile Communications,” Wiley-Interscience, 1974.

4. J. Lempiäinen, M. Manninen, ”Radio Interface System Planningfor GSM/GPRS/UMTS,” Kluwer Academic Publishers 2001.

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