SLS overview

SLS OVERVIEWCenter of Wireless Studies (CWS) labs School of Engineering- Cairo University

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Mohamed F. MarzbanMay 12th, 2014

Agenda

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Code FlowMain

Simulation Loop

Link Quality Model

Link Performance

model

Network Generation

Introduction

Conclusion

References

SLS overview

Introduction• The SLS is developed by Institute of Telecommunications,

Vienna University [1]

• Importance of SLSsystem-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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SLS overview

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 eNBsIt is composed of pixels

• Create a pathloss mapChoose a pathloss modelFor each pixel in the ROI, the pathloss is calculated

for all Primary eNBs

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SLS overview

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Pixel assignment for primary eNBs after adding pathloss only

SLS overview

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 UsersCreate a number of Users at each eNB sectorSpecify 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

SLS overview

Code Flow - Main Simulation Loop

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SLS overview

Link Quality Model• For each sector, Interferers taking into account are

The closest six sitesThe other 2 sectors of the same siteSBS laying in the same sector (if exists)

• The SINR for SISO mode is calculated by

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SLS overview

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SNR [dB]

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SNR [dB]

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Link Quality Model- cont.

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SNR [dB]

BLE

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LTE BLER for CQIs 1 to 15

CQI 1CQI 2CQI 3CQI 4CQI 5CQI 6CQI 7CQI 8CQI 9CQI 10CQI 11CQI 12CQI 13CQI 14CQI 15

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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

SLS overview

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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SLS overview5/12/2014 12/14

SLS overview

Conclusion

• The SLS focuses on network related issues

• In SLS, the physical layer is abstracted by simplified models providing Low ComplexityHigh 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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SLS overview

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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SLS overview

Thanks

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Questions?