1. A Flexible Resource Allocation and Scheduling Framework for Non-real-time Polling Service in IEEE 802.16 Networks Fen Hou, James She, Pin-Han Ho, and Xuemin (Sherman) Shen Dept. of Electrical and Computer Engineering, Waterloo University IEEE Transactions on Wireless Communications, Vol. 8, No 2, Feb. 2009

2. 2 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Agenda  Introduction  Resource Allocation and Packet Scheduling Framework  Numerical Results  Conclusions

3. 3 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Introduction  Four types of services defined in IEEE 802.16 standard  Unsolicited Grant Service (UGS)  Real-time Polling Service (rtPS)  Non-real-time Polling Service (nrtPS)  Best Effort (BE) Other Types (20 %) nrtPS (80 %) Total Internet Bandwidth C. Fraleigh, S. Moon, B. Lyles, et al., “Packet-level traffic measurements from the sprint IP backbone,” IEEE Network, vol. 17, no. 6, pp. 6-16, 2003.

4. 4 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報  Resource allocation and scheduling for nrtPS  Minimum throughput requirements  Resource utilization  Acceptable delay  For 3GPP standard, the delay constraints for nrtPS is [50,300] ms  How  A flexible and effective framework for nrtPS traffic in IEEE 802.16 networks  Analytical model  Selective ARQ mechanism  AMC scheme Introduction Contradictory relation

5. 5 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Yes Resource Allocation and Packet Scheduling Framework -Overview How many SSs are scheduled in this frame How many bandwidth is granted to a connection (1) Acceptable delay (2) Average channel condition (1) Acceptable delay (2) Average channel condition Minimum bandwidth requirement of a nrtPS connection AVG. channel condition of any SS change ? AVG. channel condition of any SS change ? No Acceptable delay of the connection change ? Acceptable delay of the connection change ? No Min. BW requirement of the connection change ? Min. BW requirement of the connection change ? No How many bandwidth is granted to a connection Yes

6. 6 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Questions  How many SSs are selected at each MAC frame (h)  Resource utilization  Packet delivery delay of each SS  How many bandwidth is granted for a served SS (L)  Minimum bandwidth requirement of a nrtPS connection

7. 7 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Assumptions  Tagged SSs VS. Tagged Queue  Each SDU is fragmented to F PDUs with an equal size of B bits  Feedback information is sent by SS in UL-ACK channel  Resource are available for nrtPS traffic admitted into network at each MAC frame  When a queue is scheduled, it has PDUs waiting for transmission

8. 8 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Wireless channel model  FSMC (Finite State Markov Channel) model

9. 9 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework Gamma Function of m m: Nakagami fading parameter Raleigh fading channel: m=1 Complementary incomplete Gamma Function Ex: If m=1, = b2, π(2)= e -1 - e -2

10. 10 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  For a slow fading channel, the state transition matrix for the FSMC can be expressed as follow

11. 11 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework

12. 12 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework

13. 13 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Analysis of service probability for an SS  Definition  The probability for an SS to obtain the service at a DL subframe  Three groups for SSs  Suppose the channel state of the tagged SSs is at state n  Group 1 (G1, K1) : SSs with channel condition better than state n  Group 2 (G2, K2) : SSs with the same channel condition as state n  Group 3 (G3, K3) : SSs with channel condition worse than state n How many SSs are selected at each MAC frame (h)

14. 14 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  If (k1>h or k1=h)  Number of SSs with better channel conditions (k1) > or = Number of SSs selected in this frame (h)  All selected SSs should be come from G1 G1G2G3 K1=4 K2=3 K3=5 Scheduled Set h=2

15. 15 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  If (k1<h)  Number of SSs with better channel conditions (k1) < Number of SSs selected in this frame (h)  Selected SSs come from G1 and G2 G1G2G3 K1=4 K2=3 K3=5 Scheduled Set h=6

16. 16 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  The probability of the tagged SS obtains TXOP The probability that all SSs without tagged SS in G1, G2 and G3

17. 17 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Assume M SSs in the networks  α 1 is the number of possible combinations for selecting k 1 from (M-1)  α 2 is the number of possible combinations for selecting (k 2 -1) from (M-k 1 -1) The total number of possible

18. 18 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  The probability of the tagged SS obtains TXOP

19. 19 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Analysis of inter-service time State of the tagged SS obtains TXOP at state 1 State of the tagged SS losses TXOP at state 1

20. 20 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  The transition probability of the group states

21. 21 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Let m denote the inter-service time  The duration (in unit of frame) between two successive transmission chances for the tagged queue

22. 22 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Analysis of Goodput

23. 23 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Allocation and Packet Scheduling Framework  Analysis of Delivery Delay of a PDU

24. 24 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Numerical Results  Simulation Settings  Channel model : Rayleigh fading channel model  Number of SSs : 20  DL/UL subframe duration : 1.25 / 1.25 ms  OFDM symbol duration : 23.8 μs  Channel bandwidth : 10 MHz

25. 25 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 PDU Delivery Delay VS. h  h: Number of SSs selected at each MAC frame SS 1 : AVG. SNR = 10 db SS 11 : AVG. SNR = 25 db SS 16 : AVG. SNR = 25 db

26. 26 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Inter-service time VS. h  h: Number of SSs selected at each MAC frame SS 1 : AVG. SNR = 10 db SS 11 : AVG. SNR = 25 db SS 16 : AVG. SNR = 25 db

27. 27 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Resource Utilization VS. h  h: Number of SSs selected at each MAC frame

28. 28 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Goodput VS. h  h: Number of SSs selected at each MAC frame SS 1 : AVG. SNR = 10 db SS 11 : AVG. SNR = 25 db SS 16 : AVG. SNR = 25 db

29. 29 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Conclusion  A efficient resource allocation and packet scheduling framework for nrtPS applications in IEEE 802.16 networks  An analytical model  A practical guideline to select appropriate parameters for satisfying the throughput requirement, delay and resource utilization

30. Thank You !!

31. 31 Speaker : Chi-Tao Chiang ( 蔣季陶 ) Meeting 報告簡報 Gamma Function  Definition  An extension of the factorial function to real and complex numbers.  For a complex number z with positive real part the Gamma function is defined by