Flexibility/Closer Cooperation 86 - X Views in the EU and Applicant States

X Views in the EU and Applicant States

Appendix 1 Flexibility/Closer Cooperation 86

For each TBC transmitter, Txi, Atoll calculates the selected parameter at each Txi inside its calculation area. Results are shown on each pixel, each pixel acting as a transmitting terminal. Hence, transmitters are here (non-interfering) receivers.

Coverage prediction parameters to be set are:

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

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

Two interfaced predictions are available:

• One prediction which shows on each pixel UL losses or UL signal levels

• One prediction which shows on each pixel UL C/I levels.

Additional studies such as codec modes and coding schemes predictions are used during simulations but are not graphically available.

3.5.1 DL Service Area Determination

Atoll uses parameters entered in the Condition tab of the coverage prediction properties dialog box to determine the service areas of the TBC transmitters.

We can distinguish eight 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.

• No max range is set.

3.5.1.1 All Servers

The service area of Txi corresponds to the pixels :

3.5.1.2 Best Signal Level and an Overlap Margin

The service area of Txi corresponds to the pixels :

For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

MinimumThresholdP_rec^Txi tt MaximumThreshold

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

MinimumThresholdP_rec^Txi tt MaximumThreshold

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

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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.

3.5.1.3 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.

3.5.1.4 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.

3.5.1.5 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 : P_rec^Txi tt Best

ji P_rec^Txj tt  M–



For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

MinimumThresholdP_rec^Txi tt MaximumThreshold

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

P_rec^Txi tt 2^ndBest

ji P_rec^Txj tt  M–



For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

MinimumThresholdP_rec^Txi tt MaximumThreshold

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

P_rec^TxiBCCH Best

ji P_rec^TxjBCCH M–



MinimumThresholdP_rec^Txi tt MaximumThreshold

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.

3.5.1.6 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.

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.

3.5.1.7 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.

For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

P_rec^TxiBCCH 2^ndBest

ji P_rec^TxjBCCH M–



For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

MinimumThresholdP_rec^Txi tt MaximumThreshold

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

P_rec^TxiBCCH Best

ji P_rec^TxjBCCH M–



P_rec^Txi tt

For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

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.

MinimumThresholdP_rec^Txi tt MaximumThreshold

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

P_rec^TxiBCCH Best

ji P_rec^TxjBCCH M–



P_rec^Txi tt

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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.

3.5.1.8 Best Idle Mode Reselection Criterion (C2)

Such type of coverage is useful :

• To compare idle and dedicated mode best servers for voice traffic

• Display the GPRS/EDGE best server map (based on GSM idle mode) The path loss criterion C1 used for cell selection and reselection is defined by:

The path loss criterion (GSM03.22) is satisfied if .

The reselection criterion C2 is used for cell reselection only and is defined by:

is the Cell Reselect Offset defined for the transmitter.

The service area of Txi corresponds to the pixels :

And

The Best function considers the highest value from a list of values.

On each pixel, the transmitter with the highest C2 value is kept. It corresponds to the best server in idle mode. C2 is defined as an integer in the 3GPP specifications, therefore, the C2 values in the above calculations are rounded down to the nearest integer.

3.5.2 Coverage by UL Signal Level

3.5.2.1 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).

3.5.2.2 Display Types

UL signal levels and UL losses calculations are explained in "UL Signal Level" on page 125. It is possible to display the coverage by UL signal level with colours depending on any transmitter attribute or other criteria such as:

3.5.2.2.1 UL Signal Level (in dBm, dBµV, dBµV/m)

Atoll calculates the signal level received at each transmitter on its service area from surrounding pixels. A pixel of a service area is coloured if the UL signal level is greater than or equal to the defined minimum thresholds (pixel colour depends on signal level). Coverage consists of several independent layers whose visibility in the workspace can be managed. There are as many layers as transmitter service areas. Each layer shows the different UL signal levels at the transmitter on its service area.

3.5.2.2.2 Best UL Signal Level (in dBm, dBµV, dBµV/m)

Atoll calculates the signal level received at each transmitter on its service area from surrounding pixels. When other service areas overlap the studied one, Atoll chooses the highest value. A pixel of a service area is coloured if the UL signal level is

For pure signal level-based calculations (not C/I or C/(I+N)), can be replaced

with or .

C1 = P_rec^TxiBCCH MinimumThreshold BCCH–   C10

C2 = C1+CELL_RESELECT_OFFSET CELL_RESELECT_OFFSET

MinimumThresholdP_rec^TxiBCCHMaximumThreshold

P_rec^Txi tt L_total^Txi _–_DL L_path^Txi

C2^TxiBCCH Best

j C2^TxjBCCH

greater than or equal to the defined thresholds (the pixel colour depends on the signal level). Coverage consists of several independent layers whose visibility in the workspace can be managed. There are as many layers as transmitter service areas.

Each layer shows the different UL signal levels at the transmitter on its service area.

3.5.2.2.3 UL Total Losses (dB)

Atoll calculates total losses from the terminal at each transmitter on its service area. A pixel of a service area is coloured if UL total losses are greater than or equal to the defined minimum thresholds (pixel colour depends on UL total losses). Coverage consists of several independent layers whose visibility in the workspace can be managed. There are as many layers as service areas. Each layer shows the different UL total losses at the transmitter on its service area.

3.5.2.2.4 Minimum UL Total Losses (dB)

Atoll calculates total losses from the transmitter on each pixel of each transmitter service area. When other service areas overlap the studied one, Atoll chooses the lowest value. A pixel of a service area is coloured if UL total losses are greater than or equal to the defined minimum thresholds (pixel colour depends on total losses). Coverage consists of several independent layers whose visibility in the workspace can be managed. There are as many layers as service areas. Each layer shows the different total losses levels in the transmitter service area.

3.5.3 Coverage by UL C/I

An UL C/I coverage predictions is available. It provides the UL C/I level at the transmitter level caused by surrounding uplink traffic.

3.5.3.1 Coverage Resolution

3.5.3.2 UL C/I Evaluation

The UL C/I level can be computed as follows, for a given MSA

• is the UL total noise at transmitter on the considered MSA

• is the received signal level at the transmitter,

• is the thermal noise (-121 dBm by default or user-defined)

• is the transmitter noise figure

• is the intra-technology UL noise rise at the considered MSA. Since UL noise rise are defined per TRX, Atoll takes the TRX UL noise rise in case of non-hopping or extracts a mean noise rise from the several TRXs composing the MSA in case of Base Band Hopping or Synthesized Frequency Hopping.

For a given transmitter having several MSAs, all possible are displayed in case the detailed results box is selected. If not, the worst results (the min C/I per transmitter) are retained.

3.5.3.3 Coverage Area Determination

For each MSA, coverage area corresponds to pixels where is between the lower and upper thresholds defined in the coverage prediction properties.

3.5.3.4 Display Types

It is possible to display the coverage predictions with colours depending on any transmitter attribute or other criteria such as:

3.5.3.4.1 C/I Level

Each pixel of the transmitter coverage area is coloured if the calculated UL C/I level is greater than or equal to the specified minimum thresholds (pixel colour depends on UL C/I level). Coverage consists of several independent layers whose visibility C

---I

MSA = P_rec^Term–N_tot^Tx

N_tot^Tx = N_thermal+NF^Tx+NR_Intra^{MSA DL}^_–_techno_log_y P_rec^Term

N_thermal NF^Tx

NR_Intra^{MSA DL}^_–_techno_log_y

C ---I

UL MSA

C ---I

UL MSA

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in the workspace can be managed. There are as many layers as transmitter service areas. Each layer shows the different UL C/I levels available in the transmitter coverage area.

3.5.3.4.2 Max C/I Level

Atoll compares calculated UL C/I levels received from transmitters on each pixel of each transmitter coverage area coverage areas overlap the studied one and chooses the highest value. A pixel of a coverage area is coloured if the UL C/I level is greater than or equal to the specified thresholds (the pixel colour depends on the UL C/I level). Coverage consists of several independent layers whose visibility in the workspace can be managed. There are as many layers as defined thresholds. Each layer corresponds to an area the highest received UL C/I level exceeds a defined minimum threshold.

3.5.3.4.3 Min C/I Level

Atoll compares UL C/I levels received from transmitters on each pixel of each transmitter coverage area the coverage areas overlap the studied one and chooses the lowest value. A pixel of a coverage area is coloured if the UL C/I level is greater than or equal to the specified thresholds (the pixel colour depends on the UL C/I level). Coverage consists of several independent layers whose visibility in the workspace can be managed. There are as many layers as defined thresholds. Each layer corresponds to an area the lowest received UL C/I level exceeds a defined minimum threshold.

3.5.4 Coverage by UL Coding Schemes

An UL Coding Scheme coverage prediction is implemented in order to be used in simulations. The prediction itself does not have any interface. for the simulations, settings are hard coded and are described hereafter.

These calculations are based on C/(I+N). Coding schemes are selected without using ideal link adaptation.

Different GPRS/EDGE configurations may be defined for transmitter and terminals. In this case, Atoll only selects the coding schemes that are common in the two, and gives priority to the thresholds defined in the transmitter configuration. If no terminal type is defined for the calculation, or if the terminal type does not have any GPRS/EDGE configuration assigned to it, Atoll only uses the GPRS/EDGE configuration of the transmitter. If the transmitter does not have any GPRS/EDGE configuration assigned to it, no coding scheme selection and throughput calculation is carried out.

In the following calculations, we assume that:

• is the DL signal level received from the BCCH of Txi on each pixel of the Txi coverage area,

• is the UL the signal level received at each transmitter on its service area from surrounding pixels

• CS is the set of all available coding schemes,

• are the values of reception thresholds for the coding schemes available in the GPRS/EDGE configuration,

• are the values of C/(I+N) thresholds for the coding schemes available in the GPRS/EDGE configuration,

• The priorities of the coding scheme lists are as follows: DBS > DAS > MCS > CS.

Since the calculations are based on C/I and C/(I+N):

• Atoll calculates the UL C/I to all the GPRS/EDGE TBC transmitters.

• The reception thresholds given for signal level C are internally converted to C/N thresholds (N is the thermal noise defined in the document database at -121 dBm by default) in order to be indexed by C/(I+N) values. C/I thresholds are also indexed by the C/(I+N) value.

For more information on UL C/I calculation, see "Coverage by UL C/I" on page 156.

3.5.4.1 Service Area Determination

Atoll uses hard-coded parameters for simulations. In that case, the DL service area is based on the option "HCS servers" with a margin of 4 dB.

The service area of Txi corresponds to the pixels :

And

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

P_rec^TxiTRX P_rec^Term

Reception Threshold

 _CS

C I+N

--- Threshold

 

 

SubcellReceptionThresholdP_rec^Txi tt

P_rec^TxiBCCH Best

ji P_rec^TxjBCCH 4dB–



P_rec^TxiBCCH

3.5.4.2 Coding Scheme Selection

Atoll selects two coding schemes from among the coding schemes available in the GPRS/EDGE configuration, such that:

For each MSA ,

And,

cs_C/N is the coding scheme determined from the C/N, and cs_C/(I+N) is the coding scheme determined from the C/(I+N) level.

Both coding schemes are the coding schemes with the lowest coding scheme numbers from the lowest priority coding scheme list.

The selected coding scheme, cs, is the coding scheme with the higher coding scheme number among cs_C/N and cs_C/(I+N): .

3.5.4.3 Throughput Calculation

For the coding scheme cs_C/N determined above, the TP = f(C) graph is internally converted to TP = f(C/N) graph. A throughput value, TP_C/N, corresponding to the C/(I+N) is determined from the TP = f(C/N) graph.

For the coding scheme cs_C/(I+N) determined above, the TP = f(C/I) graph is internally converted to TP = f(C/(I+N)) graph. A throughput value, TP_C/(I+N), corresponding to the C/(I+N) is determined from the TP = f(C/(I+N)) graph.

The final throughput is computed by interpolating between the throughput values obtained from these two graphs. The throughput interpolation method consists in interpolating TP_C/N and TP_C/(I+N) according to the respective weights of I and N values.

The resulting throughput TP is given by:

, pN is the thermal noise power (value in Watts), and p(I+N) is the interferences + thermal noise power (value in Watts).

3.5.5 Coverage by UL Codec Modes

An UL Codec Mode coverage prediction is implemented in order to be used in simulations. The prediction itself does not have any interface. for the simulations, settings are hard coded and are described hereafter.

Circuit quality indicator calculations include codec mode selection and CQI calculation. Codec modes are selected according to C/(I+N) quality without using ideal link adaptation. Once codec modes have been selected, CQI and number of used timeslots (0.5 in case of HR) corresponding to these codec modes are determined from the look-up tables.

Different codec configurations may be defined for transmitter and terminals. In this case, Atoll only selects the coding schemes that are common in the two, and gives priority to the thresholds defined in the transmitter configuration. If no terminal type is defined for the calculation, or if the terminal type does not have any codec configuration assigned to it, Atoll only uses the codec configuration of the transmitter. If the transmitter does not have any codec configuration assigned to it, no codec mode selection and CQI calculation is carried out.

If more than one codec modes satisfy the quality conditions, Atoll selects the higher priority codec mode.

In document IntergovernmentalConference 2000: themain agenda (página 41-44)