1. Robust QoS Control for Single Carrier PMP Mode IEEE 802.16 Systems Authors: Xiaofeng Bai, Abdallah Shami, and Yinghua Ye Published: IEEE TMC April 2008

2. Outline Introduction Introduction System Model System Model Uplink Request Management Agent Uplink Request Management Agent Frame Scheduling Unit Frame Scheduling Unit Simulation Simulation Conclusion Conclusion

3. Introduction Fixed frame length Fixed frame length Each connection, excepted UGS, requests bandwidth for next frame before the end of current frame Each connection, excepted UGS, requests bandwidth for next frame before the end of current frame

4. Problems How many resource do each connection real need? How many resource do each connection real need? Is the information received by BS up-to-date? Is the information received by BS up-to-date? How to reduce the control overhead? How to reduce the control overhead?

5. System Model Frame Scheduling Unit Uplink Request Management Agent Do not concern about UGS services

6. Uplink Request Management Agent

7. Symbol definition Bandwidth request for bandwidth guaranteed and imminent part Bandwidth request for bandwidth guaranteed and nonimminent part Bandwidth request for bandwidth guaranteed part Bandwidth request for nonbandwidth guaranteed part

8. Uplink Request Management Agent The connection i’s service timer at time t The connection i’s eligible bandwidth request

9. QoS Enforcement Module The connection i’s bandwidth request The connection i’s QoS timer at time t

10. SS-Request Generation Module

11. Frame Scheduling Unit Downlink Request Management Downlink Request Management Similarly to Uplink Request Management Agent Similarly to Uplink Request Management Agent Resource Allocation Module Resource Allocation Module Frame Creation Module Frame Creation Module Conversion symbol assignment into timing information Conversion symbol assignment into timing information

12. Resource Allocation Module The symbol need of the P0 request is considered first, then P1 followed by P2 requests. The symbol need of the P0 request is considered first, then P1 followed by P2 requests. If the symbol needs of every SG have been fully accommodated, the remaining symbols are assigned to each SG in proportion to the number of connections include in the SG. If the symbol needs of every SG have been fully accommodated, the remaining symbols are assigned to each SG in proportion to the number of connections include in the SG.

13. Resource Allocation Module The Pi request in bytes of the jth SG The number of bits carried by one modulated symbol of the jth SG The Pi request in symbols of the jth SG The symbols earned by the Pi request of the jth SG The extra symbols possibly assigned to the jth SG The integer number of symbols finally assigned to the jth SG

14. Simulation

15. UCSA: uncontrolled scheduling algorithm Each uplink connection sends individual bandwidth requests over the uplink. Each uplink connection sends individual bandwidth requests over the uplink. The symbol needs are estimated only based on the link capacity information when each connection is established. The symbol needs are estimated only based on the link capacity information when each connection is established. The symbol needs of all rtPS connections are accommodated first, then all nrtPS connections, followed by all BE connections. The symbol needs of all rtPS connections are accommodated first, then all nrtPS connections, followed by all BE connections. Any nrtPS connection could be serviced only when every rtPS connection queue is evacuated and no BE connection could be serviced if any rtPS and nrtPS packet is backlogged. Any nrtPS connection could be serviced only when every rtPS connection queue is evacuated and no BE connection could be serviced if any rtPS and nrtPS packet is backlogged.

16. uplink rtPS connection of SS5

17. uplink nrtPS connection of SS6

18. uplink BE connection of SS5

19. uplink rtPS connection of SS5

20. At time 2.0 second, the links from SS8 to the BS degrade from 64-QAM to QPSK. At time 2.0 second, the links from SS8 to the BS degrade from 64-QAM to QPSK. At time 4.0 second, the links from SS8 to the BS recover from QPSK to 64-QAM At time 4.0 second, the links from SS8 to the BS recover from QPSK to 64-QAM

21. uplink rtPS connection of SS8

22. uplink nrtPS connection of SS8

23. uplink rtPS connection of SS7

24. uplink nrtPS connection of SS9

25. uplink BE connection of SS8

26. uplink rtPS connection of SS8

27. Conclusion The proposed SCSA scheme enable each connection’s contracted QoS parameters to control the service provided to the connection, which ensures the per-connection QoS guarantee. The proposed SCSA scheme enable each connection’s contracted QoS parameters to control the service provided to the connection, which ensures the per-connection QoS guarantee. Signaling overhead is reduced. Signaling overhead is reduced. The proposed scheme is robust against wireless link degradation at a particular SS. The proposed scheme is robust against wireless link degradation at a particular SS.