Achieving “Quality of Service” in IEEE802.16 Networks running on the Distributed Mesh mode

1. Achieving “Quality of Service” in IEEE802.16 Networks running on the Distributed Mesh mode Awadh Al Shukaili Dr. NaveenChilamkurti La Trobe University Melbourne, Australia

2. Outline • Overview • Initial Direction • Related Work • Proposal • Simulation • Results & Analysis • Conclusion • Future Work

3. Overview – IEEE802.16 • Architectural Topologies • Point to Multipoint Mode • Small coverage • Higher deployment cost • QoS easily assured • Mesh Mode • Large coverage • Lower deployment cost • QoS not easily assured

4. Overview – Mesh Mode • Mesh Mode • Centralized • Base Station central scheduling • Slower Scheduling • Distributed (Coordinated) • Two-hop neighbourhood scheduling • Scalable • Faster Scheduling

5. Initial Direction • Targets • High throughput • Low Packet Delay rate • Low Packet Error/Drop rate • Priority Fair bandwidth distribution • Improvement areas • Routing Scheme • Transmission Coordinator • Bandwidth Manager • Packet Scheduler

6. Related Work • Cicconetti. C, Akyildiz. I.F, Lenzini. L. • Deficit Round Robin (DRR) Bandwidth Manager & Packet Scheduler • Zhang, Yong, et al. • Static Reservation Bandwidth manager • R, Jain. • Self-Clocked Fair Queuing (SCFQ)

7. Proposal • Consists of three parts • DRR Bandwidth Manager • SCFQ Packet Scheduler • Admission Control • Assumptions • Flow Destination is always the BS • Static tree based topology • All nodes use the same burst profile • Balanced maximum number of nodes

8. Proposal – DRR Bandwidth Manager • Parameters • Deficit Counter - DC • Quantum – Q • Priority Weight - W • Packet size jPi • Algorithm • Locate next source • Initialize: DCi= 0, if node was not active • Calculate: DCi= DCi + (Q x Wi) • Server: DCi= DCi – Allocated bandwidth, if DCi≥ jPi • Repeat process until all flows are empty

9. Proposal – SCFQ Packet Scheduler • Parameters • Current Virtual Time (T) • Packet Size in a certain flow (jPi) • Flow Required Bandwidth (Bi) • Packet Virtual Finish Time (jPFTi) • Algorithm • Initialization: T = 0 • Queuing: jPFTi= Max(T, j-1PFTi) + (jPi/ Bi) • Serving: • Lowest jPFTifrom all flows • T = jPFTj Flow 1 3P 2P 1P Flow 2 2P 1P 2P 1P Flow 3 Assuming that all Bi are equal, packets Schedule is: 1P1, 1P3, 1P2, 1P3, 2P1, 2P3, 2P2, 3P1

10. Proposal – Admission Control • Hop-by-Hop bases • Non-Congested Network • Accepts all flows • No delay • Flows are given as much bandwidth • Congested Network • Accepts flow if source has not exceeded it limit • Claims back bandwidth from other nodes or other greedy flows • Initial flow establishing delay • None-Greedy flows ensured a constant bandwidth • Greedy flows are ensured a constant minimum bandwidth

11. Simulation • Network Simulator 2 – NS2 • TCL scripting language • C++ modules • NS2Mesh80216 Patch • DRR bandwidth manager • DRR packet scheduler • No admission control

12. Results – Trends 1 • Number CBR flows increases • Throughput • CBR: increase • VBR: constant • BE: decrease • Packet Delay • CBR: increase • VBR: constant • BE: slightly increase • Admission control must reject new flows after 2

13. Results – Trends 2 • Number VBR flows increases • Throughput • CBR: constant • VBR: increases • BE: decrease • Packet Delay • CBR: constant • VBR: decrease • BE: slightly increase • Admission control must reject new flows after 3

14. Results – Trends 3 • Number BE flows increases • Throughput • CBR: constant • VBR: constant • BE: constant • Packet Delay • CBR: constant • VBR: constant • BE: increase • Admission control must reject new flows after a certain delay threshold decided by the Admin

15. Results – Comparisons Case 1 • In most cases, SCFQ Packet scheduler + DRR Bandwidth Manager result on • Less Packet Delay • More throughput • Better Bandwidth satisfaction factor • Smoother transmission (less spurts) Case 2

16. Conclusion • Guaranteed throughput and packet delay for non greedy flows • Guaranteed minimum bandwidth for greedy flows • Non greedy flows are not effected by other flows • Admission control ensures no flows are accepted after a certain threshold • Fairness is sustained all the time • Better performance compared DRR bandwidth manager and packet scheduler • Drawbacks • Admission Control delay in congested networks • SCFQ higher computational overhead

17. Future Work • Routing scheme • Short-Widest Efficient Bandwidth proposed by Tsai, Tzu-Chieh and Wang, Chuan-Yin • Transmission Coordinator • Dynamic approach of the two-phase hold-off time scheme introduced byWang, Shie-Yuan, et al • Multi-Request-Multi-Grant scheme introduced by Wang, Shie-Yuan, Lin, Chih-Che and Fang, Ku-Han

18. Thank You – Questions! References: [1] IEEE., IEEE Standard for Local and metropolitan area networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems. The Institute of Electrical and Electronics Engineers, Inc. New Yourk : s.n., 2004. ISBN 0-7381-4070-8 SS95246. [2] Tsai, Tzu-Chieh and Wang, Chuan-Yin., "Routing and Admission Control in IEEE 802.16 Distributed Mesh Networks." Singapore : s.n., 2007. IFIP International Conference on Wireless and Optical Communications Networks, 2007. WOCN '07. pp. 1-5. [3] Wang, Shie-Yuan, Lin, Chih-Che and Fang, Ku-Han., "Improving the Data Scheduling Efficiency of the IEEE 802.16(d) Mesh Network." 2008. IEEE Global Telecommunications Conference, 2008. IEEE GLOBECOM 2008. pp. 1-5. [4] Wang, Shie-Yuan, et al., "Improving the Performances of Distributed Coordinated Scheduling in IEEE 802.16 Mesh Networks." IEEE Transactions on Vehicular Technology, July 2008, Issue 4, Vol. 57, pp. 2531-2547. [5] Zhang, Yong, et al., "Quality of Service Guarantee Mechanism in WiMAX Mesh Networks." 2008. Third International Conference on Pervasive Computing and Applications, 2008. ICPCA 2008. pp. 882-886 . [6] Liu, Fuqiang, et al., "Achieving QoS for IEEE 802.16 in Mesh Mode." Salt Lake City, Utah, USA  : s.n., July, 2005. 8th International Conference on Computer Science and Informatics. [7] Cicconetti. C, Akyildiz. I.F, Lenzini. L., "Bandwidth Balancing in Multi-Channel IEEE 802.16 Wireless Mesh Network." s.l. : IEEE 26th IEEE International Conference on Computer Communications, 2007. pp. 2108 - 2116 . [8] R, Jain., "A Survey of Scheduling Methods." Ohio State University. [Online] [Cited: 23 October 2009.] http://www.cse.wustl.edu/~jain/talks/ftp/sched/sld029.htm. [9] Open Source., The Network Simulator - ns-2. [Online] May 2009. http://www.isi.edu/nsnam/ns/. [10] University of Pisa, Georgia Institute of Technology., Ns2mesh80216. Computer Networking Group. [Online] [Cited: 24 10 2009.] http://cng1.iet.unipi.it/wiki/index.php/Ns2mesh80216. I would like take the opportunity to thank Dr. NaveenChilamkurti for his guidance, patience and support. I would also like to thank Dr. Eric Pardede for his inspiring insights.