Applicant States

The Circuit Quality Indicators coverage predictions show the areas BER, FER, and MOS values in the transmitter coverage areas.

For each TBC transmitter, Txi, Atoll calculates the selected parameter on each pixel inside the Txi calculation area. In other words, each pixel inside the Txi calculation area is considered a probe (non-interfering) receiver.

Coverage prediction parameters to be set are:

• The coverage conditions in order to determine the service area of each TBC transmitter,

• The interference and quality indicator conditions to meet for a pixel to be covered, and

• The display settings to select the displayed parameter and its shading levels.

The thermal noise (N = -121 dBm, by default) is used in the calculations if the coverage prediction is based on C/(I+N). This value can be modified by the user.

3.4.4.1 Service Area Determination

Atoll uses parameters entered in the Condition tab of the coverage prediction properties dialog box to determine the areas coverage will be displayed.

We can distinguish seven cases as below. Let us assume that:

• Each transmitter, Txi, belongs to a Hierarchical Cell Structure (HCS) layer, k, with a defined priority and a defined reception threshold.

• Each transmitter, Txi, has a codec configuration assigned.

• No max range is set.

3.4.4.1.1 All Servers

The service area of Txi corresponds to the pixels :

3.4.4.1.2 Best Signal Level and an Overlap Margin

The service area of Txi corresponds to the pixels :

And

M is the specified overlap margin (dB). The Best function considers the highest value from a list of values.

• If M = 0 dB, Atoll considers pixels the received signal level from Txi is the highest.

cm Highest Priority CM

• If M = 2 dB, Atoll considers pixels the received signal level from Txi is either the highest or within a 2 dB margin from the highest.

• If M = -2 dB, Atoll considers pixels the received signal level from Txi is 2 dB higher than the signal levels from transmitters which are 2^nd best servers.

3.4.4.1.3 Second Best Signal Level and an Overlap Margin

The service area of Txi corresponds to the pixels :

And

M is the specified overlap margin (dB). The 2^nd Best function considers the second highest value from a list of values.

• If M = 0 dB, Atoll considers pixels the received signal level from Txi is the second highest.

• If M = 2 dB, Atoll considers pixels the received signal level from Txi is either the second highest or within a 2 dB margin from the second highest.

• If M = -2 dB, Atoll considers pixels the received signal level from Txi is 2 dB higher than the signal levels from transmitters which are 3^rd best servers.

3.4.4.1.4 Best Signal Level per HCS Layer and an Overlap Margin

For each HCS layer, k, the service area of Txi corresponds to the pixels :

And

M is the specified overlap margin (dB). The Best function considers the highest value from a list of values.

• If M = 0 dB, Atoll considers pixels the received signal level from Txi is the highest.

• If M = 2 dB, Atoll considers pixels the received signal level from Txi is either the highest or within a 2 dB margin from the highest.

• If M = -2 dB, Atoll considers pixels the received signal level from Txi is 2 dB higher than the signal levels from transmitters which are 2^nd best servers.

3.4.4.1.5 Second Best Signal Level per HCS Layer and an Overlap Margin

For each HCS layer, k, the service area of Txi corresponds to the pixels :

And

M is the specified overlap margin (dB). The 2^nd Best function considers the second highest value from a list of values.

• If M = 0 dB, Atoll considers pixels the received signal level from Txi is the second highest.

• If M = 2 dB, Atoll considers pixels the received signal level from Txi is either the second highest or within a 2 dB margin from the second highest.

• If M = -2 dB, Atoll considers pixels the received signal level from Txi is 2 dB higher than the signal levels from transmitters which are 3^rd best servers.

3.4.4.1.6 HCS Servers and an Overlap Margin

The service area of Txi corresponds to the pixels :

And

And the received exceeds the reception threshold defined per HCS layer.

SubcellReceptionThresholdP_rec^TxiBCCH

P_rec^TxiBCCH 2^ndBest

ji P_rec^TxjBCCH M–



SubcellReceptionThresholdP_rec^TxiBCCH

P_rec^TxiBCCH Best

ji P_rec^TxjBCCH M–



SubcellReceptionThresholdP_rec^TxiBCCH

P_rec^TxiBCCH 2^ndBest

ji P_rec^TxjBCCH M–



SubcellReceptionThresholdP_rec^TxiBCCH

P_rec^TxiBCCH Best

ji P_rec^TxjBCCH M–



P_rec^TxiBCCH

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M is the specified overlap margin (dB). The Best function considers the highest value from a list of values.

• If M = 0 dB, Atoll considers pixels the received signal level from Txi is the highest.

• If M = 2 dB, Atoll considers pixels the received signal level from Txi is either the highest or within a 2 dB margin from the highest.

• If M = -2 dB, Atoll considers pixels the received signal level from Txi is 2 dB higher than the signal levels from transmitters which are 2^nd best servers.

3.4.4.1.7 Highest Priority HCS Server and an Overlap Margin

The service area of Txi corresponds to the pixels :

And

And Txi belongs to the HCS layer with the highest priority. The highest priority is defined by the priority field (0: lowest).

And the received exceeds the reception threshold defined per HCS layer.

M is the specified overlap margin (dB). The Best function considers the highest value from a list of values.

• If M = 0 dB, Atoll considers pixels the received signal level from Txi is the highest.

• If M = 2 dB, Atoll considers pixels the received signal level from Txi is either the highest or within a 2 dB margin from the highest.

• If M = -2 dB, Atoll considers pixels the received signal level from Txi is 2 dB higher than the signal levels from transmitters which are 2^nd best servers.

3.4.4.2 Coverage Display

3.4.4.2.1 Coverage Resolution

The resolution of the coverage prediction does not depend on the resolutions of the path loss matrices or the geographic data and can be defined separately for each coverage prediction. Coverage predictions are generated using a bilinear interpolation method from multi-resolution path loss matrices (similar to the one used to calculate site altitudes, see "Path Loss Calculation Prerequisites" on page 57 for more information).

3.4.4.2.2 Display Types

It is possible to display the coverage predictions with colours depending on criteria such as:

BER

Only the pixels with a codec mode assigned are coloured. The pixel colour depends on the BER value. Coverage consists of several independent layers whose visibility in the map window can be managed. There are as many layers as transmitter coverage areas and BER display thresholds. Each layer shows the BER in the transmitter coverage area.

FER

Only the pixels with a codec mode assigned are coloured. The pixel colour depends on the FER value. Coverage consists of several independent layers whose visibility in the map window can be managed. There are as many layers as transmitter coverage areas and FER display thresholds. Each layer shows the FER in the transmitter coverage area.

MOS

Only the pixels with a codec mode assigned are coloured. The pixel colour depends on the MOS value. Coverage consists of several independent layers whose visibility in the map window can be managed. There are as many layers as transmitter coverage areas and MOS display thresholds. Each layer shows the MOS in the transmitter coverage area.

In the case two layers have the same priority, the traffic is served by the transmitter for which the difference between the received signal strength and the HCS threshold is the highest. The way the competition is managed between layers with the same priority can be modified. For more information, see the Administrator Manual.

SubcellReceptionThresholdP_rec^TxiBCCH

P_rec^TxiBCCH Best

ji P_rec^TxjBCCH M–



P_rec^TxiBCCH

Max BER

Only the pixels with a codec mode assigned are coloured. The pixel colour depends on the highest BER value among the BER values for all the transmitters covering the pixel. Coverage consists of several independent layers whose visibility in the map window can be managed. There are as many layers as BER display thresholds. Each layer shows the BER value.

Max FER

Only the pixels with a codec mode assigned are coloured. The pixel colour depends on the highest FER value among the FER values for all the transmitters covering the pixel. Coverage consists of several independent layers whose visibility in the map window can be managed. There are as many layers as FER display thresholds. Each layer shows the FER value.

Max MOS

Only the pixels with a codec mode assigned are coloured. The pixel colour depends on the highest MOS value among the MOS values for all the transmitters covering the pixel. Coverage consists of several independent layers whose visibility in the map window can be managed. There are as many layers as MOS display thresholds. Each layer shows the MOS value.

In document IntergovernmentalConference 2000: themain agenda (página 37-41)