The document provides an overview of the System Level Simulator (SLS). The SLS focuses on network-level issues through simplified physical layer models. It abstracts the physical layer to provide both low complexity and high accuracy. The SLS simulates network contexts like interference management and scheduling. It generates a hexagonal grid of base stations, assigns user equipments, and models path loss, shadow fading, and small-scale fading over simulation loops. Key outputs are signal-to-interference-plus-noise ratio, channel quality indicator, block error rate, and user throughput. The combination of SLS and link-level simulator allows detailed simulation of physical and network layers.

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-CQI mapping model
SNR [dB]
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Link Quality Model- cont.
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BLER
LTE BLER for CQIs 1 to 15
CQI 1
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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
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Questions?