1. Tehuang Liu and Wanjiun Liao National Taiwan University, Taipei Taiwan IEEE GLOBECOM 2008

2.  Introduction  Network Model  A Universal Algorithm for Constructing Input Network Topologies  Performance Evaluation  Conclusion

3.  Most existing static channel assignment algorithms are based on specific network topologies  tree  k-connected graph  same topology as that in the singe-channel environment  In this paper, we refer to this pre-determined network topology as the input network topology of the channel assignment algorithm.

4.  Impact of Input Network Topologies on Network Capacity  Network Connectivity  Radio Utilization  Channel Diversity  Quality of Active Links

5.  Transit Access Point  One or multiple radios  Transmission range: r  Interference range: R (>=r)  Network Topology  G=(V,E)

6.  Link Quality Quantification  Bad-Quality Link Elimination  Radio Utilization Enhancement

7.  Link Quality Quantification  Unit Transmission Time(UTT)  decide whether a link in G shall be included in G i Data rate Packet loss rate Dijkstra’s algorithm

8.  Bad-Quality Link Elimination =>

9.  Radio Utilization Enhancement the number of radios of node v

10.  Radio Utilization Enhancement 2 2

11.  NS-2  9-node grid WMN  Node has two radios  Five non-overlapping channels={a, b, c, d, e}  80.211a: TR= 225m, IR= 450m  Transmission rate: randomly (6~54 Mbps)  Packet error rate: 0.1%, 0.5%, 1%  Dynamic traffic model: Poisson

12. Load-Aware Channel Assignment (LACA), WCNC 2005 Integer Linear Programming (ILP),IEEE SECON 2005 MOBIHOC 2005

13. LACA ILP

14.  We show how the input network topology for the channel assignment algorithm affects several key factors that influence the network capacity  network connectivity  radio utilization  channel diversity  quality of active links  We propose an algorithm for constructing efficient input network topologies for arbitrary channel assignment algorithms to increase the capacity gain due to multiple channels.