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Instructions

Table of Contents

Tab Window  Antenna Selection    Band    Beamwidth    Gain     Name    ElTilt

  BTS Parameters    Mechanical Tilt    Orientation     Power    Propagation Model    Tilt Method    3D Method

Plot Window

Link Calculator

  Normal Input Parameters    TRX Output Power    Combiner Loss    Feeder Loss    Jumper Loss    Antenna Gain    TMA Tx Insertion Loss    TMB Tx Gain    Fading Margin (BTS)    Diversity Gain    BTS Sensitivity    BTS Noise Figure    TMA/TMB Rx Noise Figure    TMA/TMB Rx Gain

  Calculated / Alternative Input    Cabinet Power    TMB Output Power

    ERP    Bandwidth    BTS Noise Figure    Required S/N    System NF without TMA    System NF with TMA    Sensitivity Gain

  MS Parameters    MS Output Power    MS Antenna Gain    Fading Margin    MS Sensitivity

 

Tab Window

Antenna Selection Parameters

Band

Choose frequency band for your antenna. Selecting a band will filter the below choices.

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Beamwidth

Choose a nominal horizontal beamwidth to narrow down the selection.

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Gain

Choose a nominal gain to further narrow down the selection. Gain is expressed in dBi.

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Name

Choose an antenna by name. The names are on the form family-band-beamwidth-gain-downtilt-antenna connctor

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Eltilt

Choose electrical downtilt. Fixed antenna downtilt will only have one option here which will be chosen by default. For variable electrical tilt antennas (AEDT), the available antenna patterns for each measured tilt will be listed.

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Frequency

Choose what measurement frequency to use for the chosen antenna. By default the first frequency in the list of available frequencies will be chosen. Please note that it is important to choose a frequency for multiband antennas in order for the coverage calculation to calculate for the right frequency band.

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BTS Parameters

The following BTS parameters can be changed; Mechanical tilt, Antenna Orientation, Antenna Input power, Propagation model, Tilt Method

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Mechanical Tilt

Set the mechanical tilt in whole degrees. Positive numbers means uptilt, negative numbers means downtilt.>

Default :    0

Range :    -90 - +90 degrees

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Orientation

Set the antenna direction. 0 means north and will increase clockwise.

Default :    0

Range :    0 - 359 degrees

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Power

The power setting indicates the power measured in dBm at the antenna input terminal. The power setting should hence correspond to the base station output power minus any external combiner and feeder losses in the normal BTS case. The ERP (Effective Radiated Power) will be power setting plus antenna gain. To change the power setting, just edit the value or click on the link calculator that will bring up a small calculator for you.

Default value : 38 dBm

Range:    0 - 50 dBm

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Propagation Model

Choose propagation model to use for this option when calculating image in plot window. Choose the same model for all options unless you deliberately want to compare models. Three types of models are available:

Free-Space:

Statistical: Okumura-Hata model with corrections for rural, suburban and urban areas respectively. Model also includes correction for frequencies above 1000 MHz as recommended by Cost 231 project.

Terrian: Prediction files are important from a radio planning system that will incorporate shadowing effects from terrain elevation and morphology. 

Frequency will be picked from the frequency box above.

Default :    Free-Space

Range :     Free-Space, Terrain or Statistical       

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Tilt Method

Choose a tilt method. The simplified model will not take into account changes in horizontal angles towards the antenna when antenna is tilted.

Default :    Simplified

Range :     Simplified, Correct        

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Link Calculator Instructions

BTS Parameters

Normal Input

TRX Output Power

Set the TRX output power.

Default:    42 dBm (16 Watts, typical value for GSM equipment)

Range:      Manufacturer dependent. Over 46 dBm (40 Watts) is unusual.

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Combiner Loss

Total transmit losses in BTS between TRX and antenna feeder. Includes combiner, filter and duplex losses.

Default:    - 1 dB

Range:    -6 to 0 dB

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Feeder Loss

Loss of feeder from cabinet to top of mast. Loss is dependent mainly on length and dimension of feeder. Loss is also frequency dependent. Feeder loss is assumed to include "normal" jumper cables between actual antenna feeder and BTS cabinet and antenna respectively.

Default: -3 dB

Range: -10 to 0 dB

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Extra Jumper Loss

Loss of additional jumper required in case of TMA or TMB.

Default: - 0.5 dB

Range:     0 to -1 dB

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Antenna Gain

Gain expressed in dBi of BTS antenna.

Default: Picked up from Chosen antenna. 18 dBi if no antenna is chosen (typical high gain 65 degree antenna)

Range: 0 to 25 dBi

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TMA Tx Insertion Loss

Transmit insertion loss for TMA. In case of shared feeders for receive and transmit (duplex), the TMA will introduce a small loss in the transmit path. Only applicable in case of equipment = TMA. Setting equipment to BTS only or TMB will force this value to 0.

Default: -0.4 dB

Range: -1 to 0 dB.

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TMB Tx Gain

Gain of Tower Top Power Amplifier. Gain is port to port, i.e. includes insertion loss.

Default: 5 dB

Range: Allgon manufactures devices that ranges from typically 5 to 12 dB gain. Maximum output power is 43 dBm for all devices but the higher gain can be utilized to boost range of low power BTS's or reduce

TRX output power. TRX power is not reduced automatically when gain is altered.

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Fading Margin (BTS)

Fading margin required to provide sufficent voice quality. Includes margin for short term fading (dynamic channel) and log normal fading.

Default: 15 dB

Range: 0 to 30 dB

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Diversity Gain

Required signal increase in a noise limited environment that would equal the quality improvement by using diversity. Gain depends on manufacturer diversity implementation, antenna diversity arrangement (horizontal, vertical, polarisation), spacing between antennas, quality threshold where gain is identified, propagation conditions and speed of mobile etc.

Default: 5 dB

Range: 2 to 8 dB

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BTS Sensitivity

Minimum input signal to base staion equipment to give sufficient link quality measured at BTS cabinet input under static condition.

Default: -107 dBm (typical value for GSM equipment)

Range: System and manufacturer dependent.

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TMA/TMB Rx Noise Figure

Noise figure of receive side Tower Top Amplifier (LNA).

Default: 2 dB

Range: 1.5 to 5 dB

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TMA/TMB Rx Gain

Gain of receive side Tower Top Amplifier (LNA).

Default: 12 dB

Range: Allgon manufactures devices that ranges from 5 to 15 dB gain.

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Calculated / Alternative Input

The following are parameters that are calculated from the normal input parameters when the "calculate now" button is pressed. If any of these parameters are known rater than the corresponding "normal" parameter, they can be typed in a the corresponding "normal" parameter is calculated when the alternative calculation button is pressed. The alternative calculation button is marked with a red arraw and located next to the alternative input parameter.

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Cabinet Power

Calculated output power at the top of the BTS equipment.

Formula:

TRX Output Power + Combiner Loss.

(parameters that normally have negative numbers in red)

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TMB Output Power

Calculated output power from TMB. Maximum output power for TMB is typically 43 dBm (per carrier).

Formula:

TRX Output Power + Combiner Loss + Feeder Loss + TX Insertion Loss + TMB Gain

(parameters that normally have negative numbers in red)

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Antenna Input Power

Calculated input power to the antenna.

Formula:

TRX Output Power + Combiner Loss + Feeder Loss + TX Insertion Loss + TMB Gain + Jumper Loss

(parameters that normally have negative numbers in red)

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ERP

Calculated effective radiated power in antenna main beam. Restricted in some countries and system, maximum of 62 dBm in GSM/PCS 1900 for example.

Formula:

Antenna Input Power + Antenna Gain

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BTS Noise Figure

Calculated noise figure.

Formula:

BTS Sensitivity - (-174 + log(Bandwidth) + Req S/N)

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Bandwidth

Channel bandwidth for system. Used to calculate BTS noise factor and sensitivity.

Default: 200 kHz (typical GSM channel)

Range: System specific.

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Required S/N

Required Signal to Noise ratio for acceptable quality. Used to calculate BTS noise factor and sensitivity.

Default: 9 dB (typical GSM value. Analogue systems may require around 18 dB while negative values are valid for spread spectrum (CDMA) systems. Remember the higher bandwidth though...)

Range: System specific.

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System NF without TMA

System noise without TMA.

Formula:

NF =

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System NF with TMA

System noise with TMA.

Formula:

NF =

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Sensitivity Gain

Uplink sensitivity gain from using TMA.

Formula

System NF without TMA - System NF with TMA

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MS Parameters

MS Output Power

Output power of Mobile Station

Default: 30 dBm

Range: System Specific. Some examples:

Mobile Class

GSM 900 GSM 1800

1 43 dBm 30 dBm2 39 dBm 24 dBm3 37 dBm 36 dBm4 33 dBm5 29 dBm

Observe that these are nominal values, actual mobile performance is normally lower.

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MS Antenna Gain

Gain of mobile stations antenna. Typically below 0 dBi for handhelds, even less if body loss is to be included.

Default: -2 dBi

Range: -7 to 3 dBi. (lower value for handheld with built in antenna and including body loss, higher value for vehicle mounted co-linear antenna)

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Fading Margin (MS)

Fading margin required to provide sufficent voice quality. Includes margin for short term fading (dynamic channel) and log normal fading.

Default: 15 dB

Range: 0 to 30 dB

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MS Sensitivity

Minimum input signal to mobile staion  to give sufficient link quality under static condition.

Default: -104 dBm (typical value for GSM equipment)

Range: System and manufacturer dependent. Also depends on mobile class in GSM systems even though most modern handsets easily outperforms recommended sensitivities.

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