Planning of Radio Network

RF Planning Tool

Regional Telecom Training Centre Hyderabad

Planning of sites

• For Coverage

• For Capacity

• To improve the Quality of the Network

Planning of sites – Existing Network

• To improve the coverage in the uncovered area

• To improve the quality of the network

• Capacity requirement

Planning of sites – New Network

• Important locations in the area

• Business area

• Residential area

• Roads and railway routes

• Rural area

How to select the sites – New Network

• Survey the area and take the Latitude/Longitudes of all the important locations

• Plot them on the RF planning tool.• Select the appropriate site locations in the map for

covering all the area to be covered and with good coverage at all the important locations.

• Then survey the selected locations above for feasibility and finalize.

• Select the type of the sites required at the above locations (Micro/Macro/Umbrella coverage)

How to select the sites – Existing Network

• Drive the entire area and take Drive test report• Analyze for coverage patches, Low quality

area• Take OMCR reports • Analyze for Capacity requirement• Import the drive test reports and the OMCR

reports for localizing the sites required.• Select the appropriate site locations in the map• Then survey the selected locations above for

feasibility and finalise.

Points to remember while selecting the sites

• Site is to be located on the high ground

• No obstructions nearby

• Preferable to take on the other side of formations like hills so as to cover wider area

• Select the buildings which will fulfill the ICNIRP (International Commission on Non Ionizing Radiation Protection)

guidelines for limiting exposure of Radiation.

Safe Exposure Limit

Parameter

Operating frequency

900 MHz 1800 MHz 2100 MHz

1.Power Density 4.5 Watt / sq.m 9.0 Watt / sq. m 10.5 Watt / sq. m

2. Electric field (V / m ) 41.25 Volt / m. 58.33 Volt / m. 63.01 Volt / m.

3. Magnetic Field 0.111 Amp. / m. 0.157 Amp. / m. 0.1696 Amp. / m.

Accuracy of the Planning tool depends on the following points

• Digital map

• Link Budget

• Propagation Model

• Accuracy of the site data

Digital Maps

• Digital Maps contains clutter, Heights and Vectors.

• Latest digital maps with high resolution

Link Budget

• It is the simple Budget calculations, which gives the minimum signal strength required for good quality of network in various conditions.

• From Link Budget, we determine the Cell Radii, Design Thresholds, Power limits etc.,

• Many of the Link Budget factors are set by either GSM Recommendations or by the Limitations of the Manufacturer equipment.

  BTS MS

TX PA OUTPUT POWER: 40.00 W ( max 40.00 W ) 2.00 W

TX PA OUTPUT POWER (dBm) 46.0 dBm 33.0 dBm

COMBINER LOSSES: 4.7 dB None

SPECIFIC TX CABLE LOSSES: 0.0 dB None

RX SENSITIVITY: -110.0 dBm -104.0 dBm

RX SENSITIVITY + DIVERSITY -114.0 dBm None

CABLE+SLANT LOSS: 3.5 dB 0.0 dB

ANTENNA GAIN (ISO.): 17.0 dBi -2.0 dBi

BODY LOSSES: 3.0 dB

OVERLAPPING MARGIN: 0.0 dB

IN CAR PENETRATION FACTOR: 0.0 dB

INDOOR PENETRATION FACTOR: 34.0 dB

OPERATING FREQUENCY: 900 MHz

EQUIVALENT E.I.R.P: 54.8 dBm

TOTAL UPLINK BUDGET: 121.5 dB

TOTAL DOWNLINK BUDGET: 119.8 dB

WORST LINK BUDGET: 119.8 dB

OUTDOOR MINIMUM FIELD: -65.0 dBm (71.3 dBµV/m)

• For calculating the minimum signal level required in different conditions like travelling in a car, using in huge buildings following additional information required.

Fade Margin

Penetration Losses

Fade Margin

• Fade Margin is the margin required to ensure that the signal remains above the minimum required level for an acceptable part of the time (acceptable is defined as 90%, 95%, 98%,...)

• The signal received by the mobile is constantly changing. From this variability, a Standard Deviation can be derived. The Fade margin is simply the multiplication of the Standard Deviation by the number of Standard Deviations required to ensure the desired level of coverage.

Standard Deviation of fading = 6 to 8dB

Confidence Level SDs

50% 055% 0.1360% 0.2665% 0.3970% 0.5375% 0.6880% 0.8585% 1.0490% 1.2995% 1.6599% 2.33

Penetration Losses

• Penetration Losses are the additional losses required to cover inside the building. In Building (or In – Car) losses should be given as a mean value and a Standard Deviation. Both must be taken into account if we wish to cover more than the “average” buildings.

• For in-building coverage, the total Standard Deviation is calculated as the square root of the sum of the squares of the Standard Deviation (Building and Fade Margin)

• From these factors, we can simply derive the required design thresholds for the system quality we wish.

Large buildings Car

Penetration Losses 16 8Standard Deviation 9 7

(S.D. due to Fade margin)2+( S.D. due to Penetration Los)2Total S.D =

= 8*8 + 9* 9 = 12.04

FOR LARGE BUILDINGS (90% coverage)

FOR Coverage in CARS (90% coverage)

Total S.D = 8*8 + 7* 7 = 10.63

Service Thresholds

Required Signal Level = Sensitivity + Penetration Losses +Fade margin

For Large buildings (90% coverage)

Level = -102+16+(1.29X12.04) = -70.5dBm

For Coverage in Cars (90% coverage)Level = -102+8+(1.29X10.63) = -80.3dBm

Propagation Models

• RF Planning tool simulates the Radio Network (Total Coverage, Coverage by Cells, Interference). It should be equivalent to the Coverage and Interference in the field.

• The tool calculates the coverage losses in the clutter and gives the coverage output. These Clutter losses in the in the tool is to be supplied in the form of Propagation Model.

Propagation Models

• Basically there are Two types of Propogation Models.

• Analytical

Based on the actual characteristics of the area

• Empirical

Based on the measurements

Most Models use a combination of these Two. Some of the models are

• Epstein – Peterson

• Okumura – Hata

• Cost – Hata

• Longley – Rice

• Standard Propagation Model

Propagation Models• These are the mathematical equations contains some constants (K1-K6)

• Standard Macrocell Model for Asset

Lp (dB) = Lp (dB) = KK11 + + KK22 log(d) + log(d) + KK33 H Hmm + + KK44 log(H log(Hmm) + ) + KK55 log(H log(Heffeff) )

+ + KK66 log(H log(Heffeff) log(d) + ) log(d) + KK77 Diffraction + Clutter factor Diffraction + Clutter factorwhere Lp, Diffraction, Clutter factor are in dB

d, Hm, Heff are in m

• Planet mode Uses

PRX=PTX+K1+K2 Log(d) +K3 Log(Heff)+K4Diffraction+K5 Log(Heff) Log(d)+K6(Hmeff)+Kclutter + Ant. Gain

K1 to K6 are the constants derived from Model Tuning.

Model Tuning is done by CW Test

The results are imported in to the planning tool. Change the values of K1 to K6 until the prediction and the measured values are minimized.

RF Planning Tool - ATOLL

Inputs Required

• Digital maps

• Propagation Models

• Antennas

• Link Budget Parameters

• Site Template

• Site database

Inputs required

• Cell Type

• Frequency Band

• Propagation model

• Calculation Radius

• Resolution

Site Data base• Latitude• Longitude• Antenna Type• Antenna Height• Antenna Azimuths• Antenna Tilt• EIRP• BCCH /TCH /BSIC

Freq Reuse Pattern

Planning tool • Open a new Project

• Define the Co-ordinate system of the map

(WGS84/UTM zone 44) in the

Tools/Options

• Import the Digital map

File/Import/Select the map select index file of Clutter and import it

Change the colors of the clutter for different clutters for easy identification

File/Import/Select the map select index file of Heights and import it for getting the Digital Terrain

File/Import/Select the map select index file of Vectors and import it

Change the colors of the Vectors for different Vectors for easy identification

Planning tool • Import the Antennas• Import the Propagation Models• In the Predictions

Right click and create new coverage by signal level

Change the values and colors in the Legend for easy identification

Right click and create new coverage by C/I level

Change the values and colors in the Legend for easy identification

Right click and create new coverage by Transmitters• Create a template for 3sector site

Create a template for 1sector site by giving the filling the required information

Creating sites

• Select the icon adjacent to Site template and click in the map. Change the Latitude and Longitude. Give the site name.

• Double click on the sector and changes in the sector may be incorporated.

• Create the sites as above

• Run for Coverage by signal to get the coverage maps of all sites.

• Run for Coverage by Transmitter to get the coverage maps Cell wise.

Frequency Plan

• Group the Total frequencies in to TWO groups for BCCH and TCH allotment.

• Double click on the sector and assign the BCCH frequencies.

• Run for signal by coverage by C/I to get the interference levels of all sites.

• Change the BCCH accordingly to get better C/I• Assign BSIC

Frequency Plan• Subgroup the TCH frequencies in to 6 groups.

• Group 1 64,111,118

• Group 2 80, 112,119

• Group 3 81,113,120

• Group 4 82, 115, 122

• Group 5 87, 116, 123

• Group 6 88, 117, 124

• Assign each group to different cells for assigning the TCH Frequencies

• MA List• 64,80,81,82,87,88,111,112,113,115,116,117,118,119,120,122,123,124

• Assign HSN for each site/Cell

• Assign BSIC for each sector

Neighbor List

• Create a neighbor list

Frequency Plan requires• Latitude / Longitude

• Antennas (Type, Height and tilt)

• Orientation of the Antennas

• BCCH / TCH Frequencies(MAIO) to be allotted

• MA List

• BSIC

• Neighbor list