Atoll General Features Version 3.3.0
LTE Technology
www.forsk.com The information presented herein is accurate to the best of our knowledge. No part of this document can be copied, reproduced or distributed in any form without prior authorisation from Forsk. Atoll is a registered trademark of Forsk. All other product or service names are the property of their respective owners. © Forsk 2015
Contents 1
Opening an Atoll document (LTE) .............................................................................................. 3
2
Manipulating Network Resources ............................................................................................. 4
3
Updating and Analysing Cell Loads ........................................................................................... 5
4
Manipulating Neighbours ......................................................................................................... 6
5
Checking the Influence of Frequency Reuse............................................................................... 7
6
Analysing and Improving a PCI Plan ................... ...................... ...................... ...................... ..... 9
7
Analysing the impact of MIMO ................... ...................... ...................... ...................... .......... 11
© Forsk 2015
Page 2
1 Opening an Atoll document (LTE) Objectives - Opening an Atoll document from an .ATL file
Exercise:
1. Open the file “Chicago _MultiRAT.atl” located in the folder: “ Material_for_exercises\Brussels\LTE\Network_Data”.
2. Select the visibility checkbox of the LTE Transmitters folder in order to make them visible
.
3. Save the document into your personal folder.
Use File > Save As to save an Atoll document into your personal folder.
© Forsk 2015
Page 3
2 Manipulating Network Resources Objectives - Working with frequency bands - Checking the LTE global parameters - Working with the LTE frame details
Exercise: The LTE Network Settings are available in the Parameters explorer
1.
.
Display the (Frequency) Bands table and verify whether the entered data are consistent with the data described below:
“E-UTRA Band 7 – 5MHz”
Based on the FDD duplexing method.
Using EARFCNs (EUTRA Absolute Radio Frequency Channel Number) from 2775 to 3425.
UL start frequency: 2500 MHz .
DL start frequency: 2620 MHz.
What’s the associated number of Frequency Blocks ? __________________________________________
“E-UTRA Band 7 – 15MHz”
Based on the FDD duplexing method.
Using EARFCNs from 2825 to 3275.
2.
UL start frequency: 2500 MHz .
DL start frequency: 2620 MHz.
What’s the associated number of Frequency Blocks ? _________________________________________
Display the Properties of the LTE Network Settings folder and verify in the Global Parameters tab whether the entered data are consistent with the data described below:
3.
Default Cyclic Prefix: “0 – Normal”
PDCCH Overhead: 2 Symbol Durations
PUCCH Overhead: 4 RBs
Display the Radio Bearers table. What’s the highest bearer efficiency (bits/symbol) that you can get?
_____________________________________________________________________________________________________ 4.
In order to verify the impact of such a configuration on the LTE Frame, right-click on the LTE Transmitters folder, then
Cells, and select Details. Check the frame details in DL and in UL. 5.
From this table, can you determine the channel bandwidth used throughout this network?
_____________________________________________________________________________________________________ 6.
How many Resource Elements (RE) per cell are available for the PDSCH?
_____________________________________________________________________________________________________ 7.
In your opinion, what is the maximum channel throughput that you can get on each cell in DL?
_____________________________________________________________________________________________________ Save the document.
© Forsk 2015
Page 4
3 Updating and Analysing Cell Loads Objectives - Updating cell traffic loads to compute LTE specific predictions - Understanding the “UL Noise Rise (dB)” parameter used in UL predictions
Exercise: LTE performance is linked to Downlink Traffic Load and Uplink Noise Rise . Those factors are defined at the Cells level and can be either set manually or committed from a Monte-Carlo simulation.
1.
2.
Open the LTE Cells table:
Verify that “Max Power (dBm)” is set to 46 dBm for all LTE cells.
Verify that “Traffic Load (DL) (%)” is set to 100% for all LTE cells.
Verify that “UL Noise Rise (dB)” is set to 3 dB for all LTE cells.
Close the LTE Cells table.
Create a “LTE: Coverage by C/(I+N) Level (UL)” coverage prediction for all LTE transmitters with the following parameters on the Condition tab:
3.
4.
Terminal = LTE Terminal .
Service = VoIP.
Mobility = Pedestrian.
On the General tab, name the prediction: “LTE: Coverage by C/(I+N) Level (PUSCH) – NR 3 dB” .
Click Calculate.
Open the LTE Cells table:
Set the “UL Noise Rise (dB)” to 10 dB for all LTE cells.
Close the LTE Cells table.
Duplicate the coverage prediction “LTE: Coverage by C/(I+N) Level (PUSCH) – NR 3 dB”, rename it
“LTE: Coverage by
C/(I+N) Level (PUSCH) – NR 10 dB” and Calculate it. 5.
Move
the
coverage
prediction
“LTE:
Coverage
by
C/(I+N)
Level
(PUSCH)
– NR
3 dB” up
over
the coverage prediction “LTE: Coverage by C/(I+N) Level (PUSCH) – NR 10 dB”. To move a map (or a folder), select it and then drag it above the other maps if you want it to be seen first. Or drag the map below the other maps if you want it to be in the background.
6.
Check both predictions alternately and verify the impact of the “UL Noise Rise” parameter.
7.
Right-click the prediction “Coverage by C/(I+N) Level (PUSCH) – NR 3 dB” and choose the “Compare with” option with the prediction “Coverage by C/(I+N) Level (PUSCH) – NR 10 dB”.
8.
9.
Click OK.
Open the LTE Cells table:
Set back the “UL Noise rise” to 3 dB for all the LTE Cells.
Close the LTE Cells table.
Save the document.
© Forsk 2015
Page 5
4 Manipulating Neighbours Objectives - Importing neighbours - Checking the consistency of a neighbour plan - Visualizing neighbours on map
Exercise: Access the Neighbours features by right-clicking the LTE Transmitters folder then Neighbours.
1.
Open the LTE Neighbours table.
2.
Then,
right-click
in
it
and
import
the
following
file:
“Material_for_exercises\Chicago\LTE\Neighbours\
Chicago_LTE _Neighbours.txt”. 3.
Close the LTE Neighbours table.
4.
Launch the “Audit” tool ( LTE Transmitters > Neighbours > LTE > Audit... ), check all conditions and run it.
5.
Select the visibility check box of the prediction: “LTE Prediction 2: Coverage by Transmitter (Best Server -Null
Margin)”. 6.
Click the Edit Relations on the map button
7.
Now, click the arrow
.
and select Display options . In Coverages, check the Highlight coverage areas option and
click OK. 8.
Click on several LTE transmitters to see their neighbour relations on the map.
9.
Click the neighbour Edit Relations button again to disable it.
10. Save the document.
© Forsk 2015
Page 6
5 Checking the Influence of Frequency Reuse Objectives - Modify frequency reuse in the network so that you can verify its impact on network quality and throughput.
Exercise:
In each cell, the assigned channel number has an impact on interference, therefore on its quality and the throughput. The aim of this part is to co mpare quality and throughput predictions with a different Frequency Reuse, assuming that a spectrum of 15 MHz is available. Two options may be considered: Using the spectrum as a single channel of 15 MHz and allocating it to all LTE cells (SFN). Splitting the band into 3 channels of 5 MHz, with 1 channel for eac h sector on each station.
1.
Open the LTE Cells table and verify that channel 2775 is assigned to all LTE cells. Then, allocate the Frequency Band “E-
UTRA Band 7 – 15MHz” along with the channel 2825 to all LTE cells.
2.
Close the LTE Cells table.
Create a “LTE: Coverage by C/(I+N) Level (DL)” prediction for all LTE transmitters with the following parameters on the
Condition tab:
3.
Terminal = LTE Terminal .
Service = Mobile Internet Access .
Mobility = Pedestrian.
On the General tab, name the prediction: “LTE: Coverage by C/(I+N) Level (PDSCH) – 1 Channel” .
Click OK.
Create a “LTE: Coverage by Throughput (DL)” coverage prediction for all LTE transmitters with the following parameters in the Condition tab:
Terminal = LTE Terminal .
Service = Mobile Internet Access .
Mobility = Pedestrian.
On the General tab, name the prediction: “LTE: Coverage by Throughput (DL) – 1 Channel” .
Click OK.
4.
On the toolbar, click Calculate
5.
Open the LTE Cells table and allocate the Frequency Band “E-UTRA Band 7 – 5MHz” to all LTE cells.
6.
Import the following file:
to calculate both predictions.
“Material_for_exercises\Chicago\LTE\Network_Data\ Brussels_Frequency_Reuse_Cells_LTE.txt” .
7.
Then, verify in the LTE Cells table that:
Channel 2775 is assigned to sectors 1.
Channel 2825 is assigned to sectors 2.
Channel 2875 is assigned to sectors 3.
© Forsk 2015
Page 7
8.
Duplicate the coverage prediction “LTE: Coverage by C/(I+N) Level (PDSCH) – 1 Channel” and rename it “LTE:
Coverage by C/(I+N) Level (PDSCH) – 3 Channels” . 9.
Duplicate the coverage prediction “LTE: Coverage by Throughput (DL) – 1 Channel” and rename it “LTE: Coverage by
Throughput (DL) – 3 Channels”. 10. On the toolbar, click Calculate
to calculate both duplicated predictions.
11. Compare the results for the two different Frequency Reuse configurations. What is your conclusion? 12. Return to the initial state by assigning channel 2775 to all LTE cells. 13. Save the document.
© Forsk 2015
Page 8
6 Analysing and Improving a PCI Plan Objectives - Checking the influence of an inconsistent PCI plan on the Reference Signal quality - Using the automatic PCI allocation tool
Exercise: 1.
Open the LTE Cells table.
Set the “Traffic Load (DL) (%)” to 0% for all LTE cells.
Close the LTE Cells table. Use Ctrl+F or directly click on the icon
to open the “Find on Map” tool.
2.
Open the “Find on Map” tool and seek successively the Physical Cell ID 0, 1 and 2.
3.
Click the Reset Display button and close the “Find on Map” tool.
4.
Right-click in the LTE Transmitters folder, select Properties, and then the Display tab. In the Label field, select Physical
Cell ID, and then click OK. Apply your changes and click OK to close the Properties dialogue. 5.
Create a “LTE: Coverage by C/(I+N) Level (DL)” prediction for all LTE transmitters with the following parameters on the
Condition tab:
Terminal = LTE Terminal .
Service = Mobile Internet Access .
Mobility = Pedestrian.
On the Display tab, select Reference Signal C/(I+N) Level (DL).
On the General tab, name the prediction: “LTE: Coverage by C/(I+N) Level (RS) – Initial PCI Plan” .
Click Calculate. Access the Physical Cell ID features (Automatic Allocation and Audit) by right-clicking the LTE Transmitters folder then AFP.
6.
7.
Launch an Audit :
In the Audit drop-down menu, make sure that Physical Cell IDs is selected.
Check all conditions within the Relation Types tab
Run the audit by clicking on Calculate.
Analyse the results provided by the tool.
What do you think of this PCI plan?
Prepare the Automatic PCI planning and verify the main prerequisites:
In the cell table, verify if: o
PSS ID and SSS ID status parameters are not Locked.
o
Physical Cell ID Domain is specified (Not mandatory).
o
A minimum Reuse distance (m) is specified (Not mandatory).
The Neighbour plan is available from exercise 4.
Verify in Network Explorer, if an Interference Matrix is available. If not, right-click on LTE Interference Matrices and select New:
© Forsk 2015
o
Keep the default parameters.
o
Select Calculate.
Page 9
8.
9.
Now, launch the “Automatic Allocation” tool:
Verify if the Neighbour plan and the Interference Matrix are considered for tha analysis.
Make sure that the SSS ID Allocation option is set to “Same per site” .
Click on Update to visualise the initial cost.
Click on Calculate.
Commit the results and close the Automatic Resource Allocation window.
Duplicate the coverage prediction “LTE: Coverage by C/(I+N) Level (RS) – Initial PCI Plan” and rename it “LTE:
Coverage by C/(I+N) Level (RS) – Enhanced PCI Plan” . 10. Calculate this new prediction. 11. Compare the results for the two different Physical Cell ID plans, especially in the City Centre. Conclusion? 12. Return to the initial state by setting the “Traffic Load (DL) (%)” to 100% for all LTE cells. 13. Save the document.
© Forsk 2015
Page 10
7
Analysing the impact of MIMO Objectives - Setting MIMO-related parameters in the network - Check the benefits of MIMO features in terms quality and throughput
Exercise: 1.
2.
Open the LTE Cells table.
Set the “Traffic Load (DL) (%)” to 25% for all LTE cells.
Close the LTE Cells table.
Create a “Coverage by Throughput (DL)” prediction study for all LTE transmitters with the following parameters in the
Condition tab:
3.
Terminal = LTE Terminal .
Service = High Speed Internet .
Mobility = Pedestrian.
On the General tab, name the study: “Coverage by Throughput (DL) – No MIMO”.
Click Calculate.
Create a “Coverage by C/(I+N) Level (DL)” prediction study for all LTE transmitters with the following parameters in the Condition tab:
4.
5.
Terminal = LTE Terminal .
Service = High Speed Internet .
Mobility = Pedestrian.
On the General tab, name the study: “Coverage by C/(I+N) Level (PDSCH) – No MIMO”.
Click Calculate.
Open the Cells table:
Set the Diversity Support (DL) to Transmit Diversity
Close the Cells table.
Open the Transmitters table and verify the Number of Transmission Antenna Ports for all LTE transmitters. This parameter must be set to 2 ports for the downlink:
6.
Verify the terminal configuration for MIMO:
7.
Close the Transmitters table.
In Parameters Explorer , Traffic Parameters , Terminals, open the LTE MIMO Terminal properties. In the LTE tab, verify if MIMO is selected in Diversity support. The number of reception antenna ports must be 2. Close the LTE MIMO Terminal properties.
Create a “Coverage by Throughput (DL)” prediction study for all transmitters with the following parameters in the
Condition tab:
Terminal = MIMO Terminal
Service = High Speed Internet
Mobility = Pedestrian.
On the General tab, name the study: “Coverage by Throughput (DL) - TX Diversity” .
Click Calculate.
© Forsk 2015
Page 11
8.
Create a “Coverage by C/(I+N) Level (DL)” prediction study for all LTE transmitters with the following parameters in the Condition tab:
9.
Terminal = MIMO Terminal .
Service = High Speed Internet .
Mobility = Pedestrian.
On the General tab, name the study: “Coverage by C/(I+N) Level (PDSCH) - TX Diversity”.
Click Calculate.
Compare studies with and without MIMO – TX Diversity. What is the impact of MIMO – TX Diversity, especially at cell
edges? 10. Open the Cells table:
Set the Diversity Support (DL) to SU-MIMO then close the Cells table.
11. Duplicate the coverage prediction “LTE: Coverage by C/(I+N) Level (PDSCH) – TX Diversity” and rename it “LTE:
Coverage by C/(I+N) Level (PDSCH) – SU-MIMO”. 12. Duplicate the coverage prediction “LTE: Coverage by Throughput (DL) – TX Diversity” and rename it “LTE: Coverage by
Throughput (DL) – SU-MIMO”. 13. On the toolbar, click Calculate
to calculate both duplicated predictions.
14. Compare studies No MIMO and SU-MIMO. What is the impact of SU-MIMO, especially near the transmitters ? 15. Open the Transmitters table and set the Number of Reception Antenna Ports to 2 for all the transmitters. This configuration will have an impact in uplink. 16. Open the Cells table and select for the Diversity Support (DL), Transmit Diversity and SU-MIMO for all LTE transmitters. In this MIMO configuration, the tool will switch dynamically from one mode to another depending on the radio conditions. 17. Save the document.
© Forsk 2015
Page 12
