1. Joint Channel Assignment and Routing in Real Time Wireless Mesh Network Xiaoguang Li †, Changqiao Xu ‡ † College of Software Engineering, Southeast University, Nanjing, China ‡ Institute of Software, Chinese Academy of Sciences, Beijing, China † ‡ Athlone Institute of Technology, Athlone, Ireland IEEE WCNC 2009

2. Outline Introduction Interference Based Channel Assignment Performance Evaluation Conclusion

3. Introduction The performance of the IEEE 802.11 a/b/g- based WMNs can be increased via the use of multiple channels.

4. Introduction The channel allocation and interface assignment schemes ▫Static algorithms  Assign channels and interfaces permanently ▫Dynamic algorithms  Allow the wireless mesh network to adapt to the changing traffic patterns  Short term basis

5. Introduction We define the requirements of a multi-channel, multi-interface solution as follows: ▫Improve network capacity  Utilizing all the available channels and channel- switch, even if the number of interfaces is smaller than the number of available channels.

6. Introduction We define the requirements of a multi-channel, multi-interface solution as follows: ▫The interference should be considered from the start.  At that time, there is no traffic in the network. The adaptive channel switch can improve the network performance. ▫Two nodes that communicate with each other directly should share at least one common channel.

7. Enhanced AODV Route in WMNs CH4 CH7 CH3 CH1 CH11 CH6 CH9 CH11 CH4 CH8 CH12 CH7 CH3 CH1 CH6 CH11 CH8

8. Interference Based Channel Assignment A B C D E F

9. 78 12 9 1314 171819 Level=3 Level=0Level=1Level=2 Level=1Level=2 Level=3Level=4

10. Interference Based Channel Assignment 78 12 9 1314 171819 The current maximum number of neighbor List 7 2 7 2 8 3 8 3 7 2 7 2 17 2 2

11. Interference Based Channel Assignment 78 12 9 1314 171819 The current maximum number of neighbor List 13 4 8 3 12 3 14 3 18 3 7 2 … 9

12. Interference Based Channel Assignment 78 12 9 1314 171819 The current maximum number of neighbor List 13 4 8 3 12 3 14 3 18 3 7 2 … 9

13. 78 12 9 1314 171819 pair(7,19) pair(8,18) pair(19,17) Interference Based Channel Assignment

14. 78 12 9 1314 171819 pair(7,19) pair(8,18) pair(19,17) Interference Based Channel Assignment transmittingreceiving transmittingreceiving

15. Performance Evaluation ns-2 12 channels sense range : 22 meters hear range : 44 meters This means every node is sense range can be the neighbors of each other

16. Performance Evaluation

20. Conclusion We proposed a static channel assignment algorithm KN-CA is used to avoid the interference before the traffic going. We have implemented all the system in ns-2 simulator. And the simulation results show how the performance is improved after channel switched.