1. 1 A Proportional Fair Spectrum Allocation for Wireless Heterogeneous Networks Sangwook Han, Irfanud Din, Woon Bong Young and Hoon Kim ISCE 2014

2. 2 Outlines Introduction System Model Problem Formulation Performance Evaluation Conclusion

3. 3 Introduction System Model Problem Formulation Performance Evaluation Conclusion

4. 4 Introduction Cognitive Radio – Improves the bandwidth efficiency by exploiting temporarily available frequency bands of licensed users not heavily occupied. Source [gonzalo-vazquez-vilar.eu]

5. 5 Main Issues Unused spectrum bands allocated to Secondary (Unlicensed) user. Secondary (Unlicensed) user to access temporarily spectrum hole Intelligent. So, intelligent way without causing harmful interferences with primary users The price of each allocated a frequency band is considered Introduction

6. 6 Environments Perfect Spectrum Sensing Perfect Information Exchange (No error, no delay) Multiple transmission channels/users Variant numbers of the channels/users

7. 7 Introduction System Model Problem Formulation Performance Evaluation Conclusion

8. 8 System Model – System Scenario – Spectrum Utilization Scenario

9. 9 Introduction System Model Problem Formulation Performance Evaluation Conclusion

10. 10 Problem Formulation Objective – Maximize System Utility System Utility : sum of user utility(satisfaction) User utility : log (avg. throughput/cost) Optimization Problem for Spectrum Band Allocation

11. 11 Introduction System Model Problem Formulation Performance Evaluation Conclusion

12. 12 Evaluation Environment System Assumptions – Perfect spectrum sensing and information Exchange – Multiple channels/users – Different network access cost – Data aggregation of simultaneous transmission from different networks Performance Measurement – Total (system) throughput – User throughput Simulation tools – MATLAB

13. 13 Evaluation Results Same Cost(4,4,4,4) Different Cost(4,3,5,6) Time Average Throughput Time Average Throughput First, considering the fluidity of the user by using Cognitive radio, considering the dynamic state of fairness by the PF scheduling considering only solved the drawbacks of Round Robin. In addition to considering the price varies accordingly appearance was confirmed. RATs with same price results in similar throughput of all users and vice versa

14. 14 Introduction System Model Problem Formulation Performance Evaluation Conclusion

15. 15 A cost-efficient PF scheduling algorithm for heterogeneous networks is proposed. For the networks with different access cost, the scheduler assigns users to the networks to maximize the sum of logarithmic average cost-efficiency. The proposed scheme enhance the system efficiency compared to schemes considering equal cost for each RAT. Conclusion

16. 16 Thank You !