Scheduling in dynamic spectrum access networks using graph coloring

In a dynamic access network, multiple secondary users access and share channels that are not used by the primary users. Uncoordinated and random channel access by the secondary users access leads to decreased secondary network throughput as users in the close proximity interfere with each other. In order to better utilize the channels, we propose a scheduling technique that assigns unique time slots to all secondary users for transmission. The interference among nodes is captured using a conflict graph. Greedy graph coloring technique is applied to find time slots for every user using an approximation for the maximum number of interfering users in a Poisson distributed network. With the simulation experiments, we show how the performance of the proposed scheduling mechanism is for various network parameters¹.