Wireless Mesh Networks: Cross-Layer Scheduling

1. Wireless Mesh Networks: Cross-Layer Scheduling Jason Ernst University of Guelph Prepared for CS6650 – Mobile and Wireless Networks

2. Presentation Outline • Introduction & Background • Wireless Mesh Networks • Motivation • Fair Scheduling • Classification of Scheduling Techniques • Cross-Layering • Related Work • Current Problems • Future Work & Conclusions • Questions Jason Ernst - University of Guelph

3. Wireless Mesh Networks • WMN - Wireless Mesh Network: • Ad-hoc network with a core which has limited mobility • Mesh Router: • A wireless base station with limited or no mobility • Infrastructure of the network • Mesh Clients: • A wireless node which is fully mobile, may also act as a router in some WMNs Image: Indigo Systems – WMN for Environmental Monitoring Jason Ernst - University of Guelph

4. Motivation: Fair Scheduling • Starvation & Unequal Quality of Service (QoS) • “Greedy” flows cause other traffic to be ignored resulting in starving or unequal QoS • Nodes closer to the gateways cause farther nodes starvation or unequal QoS • In commercial applications people who pay the same amount expect the same quality of service Jason Ernst - University of Guelph

5. Motivation: Fair Scheduling Image: NC State University Elec. Eng. Dept. Jason Ernst - University of Guelph

6. Classifications of Scheduling Throughput Fairness Jason Ernst - University of Guelph

7. Classifications of Scheduling Maximum Throughput Scheduling Proportional Fairness Throughput Fairness Equal Fairness Min-Max Jason Ernst - University of Guelph

8. Motivation: Cross-Layering • Still ongoing debate as to whether cross-layering is worthwhile or not • Performance improvement and more intelligent decisions • However possibility of “spaghetti-code” or unintended effects due to unexpected interactions with other layers Jason Ernst - University of Guelph

9. Cross-Layering • Methods of Cross-Layering • Power Adaption • Adjust Power in order to avoid interference and increase fairness • Routing / MAC [J. Thomas] • Transport / LL [Wang et al.] • Rate Control • Adjust the data rates in order to achieve fairness • Network / Transpot [Neely et al.] • Transport / Network / MAC [Tang et al.] • Route Control • Change routes in order to avoid congestion • LL / network [Kuran et al.] Jason Ernst - University of Guelph

10. Related Work: Fair Scheduling • Operating Systems • User / process scheduling in interactive OS’s started in the 1960s and 70’s (multics, unix) • Wired Networks & Wireless LAN (single hop) • Ad-hoc Networks • Distributed Computing – SHARCNET • Cross-Layering: Wired Networks Jason Ernst - University of Guelph

11. Current Problems • Cross-Layered Fair Scheduling • Some papers make assumptions such as single hop networks, limited mobility, fixed topology (APs cannot be added or removed) • Assumption which treats uplink and downlink together when it may be beneficial to treat them independently • Localized VS Centralized scheduling & load balancing Jason Ernst - University of Guelph

12. Future Work • Future Work: • Identifying an area of current research to expand upon • Make use of experimentation to determine optimal parameter values, metrics for load balancing etc. • Cross Layered Optimizations on solution • Write a thesis based on the research Jason Ernst - University of Guelph

13. References • Agrawal et Al. Achieving Load Balancing in Wireless Mesh Networks Through Mulitple Gateways. IEEE. 2006. 807-812. • Bejerano, Yigal., Han, S-J., Kumar, Amit. Efficient Load-Balancing Routing for Wireless Mesh Networks. 2007. Computer Networks. 51. 2450-2466. • Chandranmenon et. Al. On the Design and Implementation of Infrastructure Mesh Networks. IEEE Workshop on Wireless Mesh Networks (WiMesh) 2005. • Cheng, S-M., Lin, Phone., Huang, Di-Wei., Yang, Shun-Ren. A Study on Distributed / Centralized Scheduling for Wireless Mesh Network. 2006. IWCMC ’06. ACM. 599-604. • Gupta, Piyush., Sankarasubramaniam, Yogesh., Stolyar, Alexander. Random-Access Scheduling with Service Differentiation in Wireless Networks. 2005. IEEE. 1815-1825. • Erwu, Liu., Shan, Jin., Gang, Shen., Luoning, Gui. Fair Scheduling in Wireless Multi-Hop Self-Backhaul Networks. IEEE AICT/ICIW 2006. • Hubaux, J-P., Salem, Ben Naouel. A Fair Scheduling for Wireless Mesh Networks. WIMESH. 2005 • Koutsonikolas, Dimitrios., M. Das., Saumitra., Hu, Charlie, Y. An Interference-aware Fair Scheduling for Multi-cast in Wireless Mesh Networks. 2008. Journal of Parallel and Distributed Computing. 68. 372-286. • Popa, Lucian., Rostamizadeh, Afshin., Karp, Richard, M., Papadimitriou, Christos., Stoica, Ion. Balancing Traffic Load in Wireless Networks with Curveball Routing. 2007. Mobihoc ‘07. ACM. 170 – 179. Jason Ernst - University of Guelph

14. References • J. Thomas, “Cross-Layer Scheduling and Routing For Unstructured And Quasi-Structured Wireless Networks” • M.S. Kuran, G. Gur, T. Tugcu, F. Alagoz, “Cross-Layer Routing-Scheduling in IEEE 802.16 Mesh Networks”, in Mobilware’08. Austria, 2008. • M. Neely, R. Urgaonkar, “Cross-layer adaptive control for wireless mesh networks,” in Ad Hoc Networks Vol . 5, pp 719-743, 2007. • J. Tang, G. Xue, W. Zhang, “Cross-Layer Design for End-To-End Throughput and Fairness Enhancement in Multi-Channel Wireless Mesh Networks,” in IEEE Transactions on Wireless Communications, Vol. 6. pp 3482-3486. October 2007. • X. Wang, K. Kar, “Cross-Layer Rate Control for End-to-End Proportional Fairness in Wireless Networks with Random-Access,” in MobiHoc ’05. Illinois, USA, 2005. • J. Tang, G. Xue, C. Chandler, W. Zheng, “Link Scheduling with Power Control for Throughput Enhancement in Multihop Wireless Network • V. Kawadia, P.R. Kumar, “A Cautionary Perspective on Cross-Layer Design,” in IEEE Wireless Communications, pp 3-11, February 2005. • I.F. Akyildiz, X. Wang, “Cross-Layer Design in Wireless Mesh Networks,” in IEEE Transactions on Vehicular Technology, Vol. 57, 2, pp 1061- 1076, March 2007. Jason Ernst - University of Guelph

15. Questions? Jason Ernst jernst@uoguelph.ca University of Guelph Advisor: Dr. Mieso Denko Jason Ernst - University of Guelph