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Frequency Allocation for WLANs Using Graph Colouring Techniques
Janne Riihijarvi, Marina Petrova and Petri Mahonen

At present, no standard frequency allocation mechanism exists for Wireless LAN access points. This has resulted in a situation where many WLAN networks use default or suboptimal channel assignments, leading to poor performance, and uneven spectrum usage. In this article, we introduce a number of frequency assignment techniques based on graph colouring algorithms, and demonstrate their effectiveness using simulations. In particular, we show that the graph colouring based approach produces very good frequency assignments, significantly reducing the number of collisions in the network, leading to substantial capacity improvement.We also suggest a preliminary message format the access points could employ to exchange information regarding the wireless channel, and elaborate on the possible protocol architectures that could be used in the actual channel allocation process.

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