This presentation takes you through the code flow of the Vienna LTE System level Simulator (SLS)

1. SLS OVERVIEW
Center of Wireless Studies (CWS) labs
School of Engineering- Cairo University
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Mohamed F. Marzban
May 12th, 2014

2. Agenda
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Code Flow
Main
Simulation
Loop
Link Quality
Model
Link
Performance
model
Network
Generation
Introduction
Conclusion
References

3. Introduction
• The SLS is developed by Institute of Telecommunications,
Vienna University [1]
• Importance of SLS
system-level simulations focus on network-related issues such as
 Interference management
 Scheduling
In standardization of LTE, simulations has to be performed on
 Physical layer (link level)
 Network context (System level)
• The SLS is supplemented by a freely-available LTE Link-Level
Simulator [2]
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4. Code Flow- Network generation
• Input Simulation parameters
• Create a hexagonal grid of equidistantly-spaced eNB sites (number of
rings=0,1,2)
• Each site has 3 sectors.
• Region Of Interest (ROI)
It is the Region containing all eNBs
It is composed of pixels
• Create a pathloss map
Choose a pathloss model
For each pixel in the ROI, the pathloss is calculated
for all Primary eNBs
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Pixel assignment for primary eNBs after adding pathloss only

6. Code Flow- Network generation- Cont.
• Generate a shadow fading map [3]
Models the obstacles in the propagation path between the UE and
eNB
• Assign the pixels to the eNBs
• Create Secondary Base stations (SBS)
• Extend the pathloss and shadow fading maps (to take into account
the SBS)
• Create Users
Create a number of Users at each eNB sector
Specify a Traffic Model e.g.: full-buffer, ftp
• Load small-scale fading channel model (time dependent)
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Pixel assignment for primary eNBs after adding pathloss and Shadow fading

8. Code Flow - Main Simulation Loop
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9. Link Quality Model
• For each sector, Interferers taking into account are
The closest six sites
The other 2 sectors of the same site
SBS laying in the same sector (if exists)
• The SINR for SISO mode is calculated by
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SNR [dB]
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SNR-CQI mapping model
SNR [dB]
CQI
Link Quality Model- cont.
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SNR [dB]
BLER
LTE BLER for CQIs 1 to 15
CQI 1
CQI 2
CQI 3
CQI 4
CQI 5
CQI 6
CQI 7
CQI 8
CQI 9
CQI 10
CQI 11
CQI 12
CQI 13
CQI 14
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• SINR-to-CQI mapping is done to ensure a BLER value less than 10%
• MCS corresponding to the CQI is obtained and throughput is calculated
based on the number of resources assigned to the user

11. Link Performance Model
• The SINR is mapped to BLER according to the CQI used.
• Via a coin toss, it is decided whether the given TB is
received correctly or not.
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12. 5/12/2014 12/14SLS overview

13. Conclusion
• The SLS focuses on network related issues
• In SLS, the physical layer is abstracted by simplified
models providing
Low Complexity
High Accuracy
• The combination of both SLS and LLS allows for detailed
simulation of both the physical layer and the network
context
• The SLS is offered for free under an academic, non-
commercial use license.
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14. References
[1] J. C. Ikuno, M. Wrulich, M. Rupp, “System level simulation of LTE networks“,
IEEE 71st Vehicular Technology Conference, Taipei, Taiwan, May 2010.
[2] C. Mehlf¨uhrer, M. Wrulich, J. C. Ikuno, D. Bosanska, and M. Rupp,
“Simulating the long term evolution physical layer,” in Proc. of the 17th
European Signal Processing Conference (EUSIPCO 2009)L, Glasgow,
Scotland, Aug. 2009.
[3] H. Claussen, “Efficient modelling of channel maps with correlated shadow
fading in mobile radio systems,” Sept. 2005.
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15. Thanks
5/12/2014 SLS overview
Questions?