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行動式 WiMAX 中具動態頻寬重配置之可適性允入控制架構

行動式 WiMAX 中具動態頻寬重配置之可適性允入控制架構. Student: Shiao-Ting Huang ( 黃筱婷 ) Adviser: Kai-Wei Ke ( 柯開維 ) Date: 2011/07/27. 1. 2. 3. 4. 5. Introduction. Proposed CAC Scheme. Analytical Model. Numerical Results. Conclusion and Future Work. Outline. 1. Mobile WiMAX Overview.

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行動式 WiMAX 中具動態頻寬重配置之可適性允入控制架構

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  1. 行動式WiMAX中具動態頻寬重配置之可適性允入控制架構行動式WiMAX中具動態頻寬重配置之可適性允入控制架構 Student: Shiao-Ting Huang (黃筱婷) Adviser: Kai-Wei Ke (柯開維) Date: 2011/07/27

  2. 1 2 3 4 5 Introduction Proposed CAC Scheme Analytical Model Numerical Results Conclusion and Future Work Outline

  3. 1. Mobile WiMAX Overview • IEEE 802.16e-2005 Mobile WiMAX

  4. Motivation • Ref. [2][3]提出了利用降階(degradation)的方法 來設計允入控制機制。 • 優點： • 使用降階的方法 • Ref.[3]中考慮delay與handoff的情況 • 缺點： • 在調整降階的方式上，降階需調降系統中該服務類別的所有連線，造成頻寬資源的浪費。 • 降階之後沒有考慮頻寬重配置，會讓降階之後讓出的多餘頻寬，無法得到有效的利用。 • 所以我們提出了要一個一個降的並加入頻寬重配置的方法，希望能大幅增加頻寬使用率。

  5. Introduction • Proposed two call admission control strategies • Bandwidth Degradation (BD_CAC) • Bandwidth Degrade and Upgrade (BDU_CAC) • 利用降階及回復等資源重配置機制 • 提高Bandwidth Utilization及降低Blocking Probability和 Dropping Probability • 給予不同的QoS類別不同的優先權，並給予遞交連線較高的優先權

  6. QoS Architecture for IEEE 802.16 MAC Protocol

  7. priority 高 低 QoS Classes

  8. 2. BDU_CAC • H: Handoff, N: New Call • Priority: H-UGS > H-ertPS > N-UGS > N-ertPS > H-rtPS > N-rtPS > H-nrtPS > N-nrtPS

  9. Degradation Algorithm 1 • (UGS, ertPS, rtPS1, rtPS2, rtPS3, nrtPS1, nrtPS2, nrtPS3) • 使用於有New Call rtPS與nrtPS的時候 • 可以讓nrtPS的連線降階，希望能盡量讓提出要求的連線都進來

  10. Degradation Algorithm 2 • 使用於UGS, ertPS, Handoff rtPS連線提出需求的時候 • 可以讓nrtPS與rtPS的連線降階，盡量讓提出要求的連線都能進來

  11. Recovery Algorithm • (UGS, ertPS, rtPS1, rtPS2, rtPS3, nrtPS1, nrtPS2, nrtPS3) • 使用於有連線要離開的時候 • 盡量把頻寬用完使得Utilization能夠提高

  12. UGS Connection

  13. ertPS Connection

  14. Handoff rtPS Connection

  15. New Call rtPS Connection

  16. Handoff nrtPS Connection

  17. New Call nrtPS Connection

  18. 3. Analytical Model • Continuous Time Markov Chain • (i, j, k, l, m, n, p, q) = (UGS, ertPS ,rtPS1, rtPS2, rtPS3, nrtPS1, nrtPS2, nrtPS3)的連線數 • (b1, b2, b3, b4, b5, b6, b7, b8) = (UGS, ertPS ,rtPS1, rtPS2, rtPS3, nrtPS1, nrtPS2, nrtPS3)之可使用的頻寬大小 • Δr = b3 - b4 = b4 - b5 Δn = b6 - b7 = b7 - b8, • (b1, b2, b3, b4, b5, b6, b7, b8)又可表示成(b1, b2, 3Δr, 2Δr, Δr, 3Δn, 2Δn, Δn) • C: 在BS中全部可讓連線使用的頻寬總量(Kbps) • R: 目前BS中剩餘的頻寬總量

  19. Analytical Model (cont.)

  20. State Transition Rate of the Markov Chain

  21. State Transition Rate of the Markov Chain (cont.)

  22. Performance Metrics

  23. Handoff Connection Dropping Prob.

  24. New Connection Blocking Prob.

  25. 4. Numerical Results

  26. Comparison of BP and DP of UGS/ertPS Connection Blocking and Dropping Probability Blocking and Dropping Probability Offered load Offered load

  27. Comparison of BP and DP of rtPS/nrtPS Connection Blocking and Dropping Probability Blocking and Dropping Probability Offered load Offered load

  28. Comparison of BU of the system Bandwidth Utilization Offered load

  29. 保留部分頻寬(UGS/ertPS) • Average Blocking Prob. = (Blocking Prob. + Dropping Prob.)/2 Blocking and Dropping Probability Blocking and Dropping Probability Offered load Offered load

  30. 保留部分頻寬(rtPS/nrtPS) Blocking and Dropping Probability Blocking and Dropping Probability Offered load Offered load

  31. 保留部分頻寬(Utilization) Bandwidth Utilization Offered load

  32. 5. Conclusion • 加入頻寬重配置機制後，由於blocking state的steady state probability隨之變大，因此造成blocking probability也跟著增加 • 舉例: 如右圖所示，(4,1,0,1,1,0,0,3)為一個blocking state，在λ=1和μ=0.2時，使用BD_CAC跳到此狀態的穩態機率為7.406347e-006，而使用的是加入頻寬重配置的BDU_CAC中，其穩態機率為1.837583e-004。 • 因此可得知在使用BDU_CAC的時候，跳到blocking state的機率增加，進而造成blocking prob.增加。

  33. Conclusion (cont.) • 只有做degradation的時候，blocking probability和dropping probability有明顯的改進。 • 除了degradation之外再加上頻寬重配置機制之後，utilization大幅增加。 • 利用調整頻寬保留比例來決定blocking probability、dropping probability和utilization的大小，以適用於不同的網路環境。

  34. Future Work • 推導rtPS與nrtPS有n個class的general form • 由於移動式網路距離與行動性的關係，因此訊號來源會呈現不斷變動的情形，探討該如何解決以及是否會對系統效能造成影響 • 加入延遲(delay)的考量

  35. Reference [1] IEEE Std 802.16-2009, “IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Broadband Wireless Access Systems,” May, 2009. [2] K. Etemad, “Overview of Mobile WiMAX Technology and Evolution,” IEEE Communications Magazine, vol. 46(10), pp. 31-40, October 2008 [3] H. Wang, W. Li, and D.P. Agrawal, “Dynamic admission control and QoS for 802.16 wireless MAN,” Wireless Telecommunications Symposium, pp. 60 - 66, Apr. 2005. [4] S. Kalikivayi, I.S. Misra, and K. Saha, “Bandwidth and Delay Guaranteed Call Admission Control Scheme for QOS Provisioning in IEEE 802.16e Mobile WiMAX,” IEEE conference on Global telecommunications, pp. 1-6, 2008. [5] Kitti Wongthavarawat, and Aura Ganz, “Packet scheduling for QoS support in IEEE 802.16 broadband wireless access systems,” International Journal of Communication Systems, vol. 16, issue 1 , pp. 81-96, February 2003

  36. Thank You ! Q&A

  37. IEEE 802.16 MAC • QoS mechanisms • Call Admission Control • Bandwidth Allocation • Scheduling • Mobility management

  38. Motivation (cont.)

  39. Degradation Algorithm (cont.)

  40. Degradation Algorithm (cont.)

  41. Recovery Algorithm (cont.)

  42. BD_CAC • H-UGS > H-rtPS > N-UGS > N-rtPS > U-nrtPS > N-nrtPS

  43. BD_CAC Transition Diagram

  44. BD_CAC Balance Equation

  45. BD_CAC Balance Equation (cont.)

  46. BD_CAC Balance Equation (cont.)

  47. BD_CAC Balance Equation (cont.)

  48. System Prameter

  49. Comparison of BP and DP of UGS Connection

  50. Comparison of BP and DP of rtPS Connection

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