1. A Maximum Fair Bandwidth Approach for Channel Assignment in Wireless Mesh Networks Bahador Bakhshi and Siavash Khorsandi WCNC 2008

2. Outline Introduction Problem formulation MFPFB Algorithm Simulation Conclusion

3. Introduction The mesh routers construct a static multi-hop wireless backbone  Interference between multiple nodes is the primary reason for the throughout degradation  Multi-Channel Multi- Radio networking is one of the approaches to reduce the interference

4. Introduction

5. The constraints in the channel assignment problem  The number of available channels is limited  Network connectivity should be maintained  The number of radios per-node is limited

6. Introduction Goal  Channel assignment and maximizing per-flow bandwidth fairness Maximizing per-flow bandwidth with fairness consideration Equalizing bandwidth assignment of flows

7. Problem Formulation The load isn’t known at beginning  use the number of routed flows on a link as the load of the link The DWIG is a directed weighted graph

8. Problem Formulation

9. Interference number of flow the number of routed flows on links the end-to-end bandwidth

10. Problem Formulation According to the front page Bandwidths of all flows

11. Problem Formulation Maximizing per-flow bandwidth is the objective of channel assignment Fairness is the second aspect of our channel assignment  Allocating equal bandwidth for all flows

12. MFPFB Algorithm the interference level on flows on link the interference level on the most interfered link available bandwidth on link the total available bandwidth

13. MFPFB Algorithm At each round of channel assignment  change channel of the most interfered link

15. MFPFB Algorithm ab = 2 X (3+1+4) = 16 bc = 3 X (2+1+4) = 21 bd = 1 X (2+3+4) = 9 de = 4 X (2+3+1) = 20 ab = 2 / (3+1+4) = 2 / 8 bc = 3 / (2+1+4) = 3 / 7 bd = 1 / (2+3+4) = 1 / 9 de = 4 / (2+3+1) = 4 / 6

16. Simulation Simulator: ns2 Number of nodes: 40 Area size: 1000 m x 1000 m The transmission range: 220 m The interference range: 350 m Random placement

17. Simulation

19. Conclusion In this paper  Formulated per-flow maximum fair channel assignment problem Directed Weighted Interference Graph  Presented a randomized greedy algorithm (MFPFB channel assignment)

20. Thank you!!