The open spectrum approach to spectrum access can achieve near-optimal spectrum utilization by letting users sense and utilize available spectrum opportunistically. However, naive spectrum assignment can lead to significant interference. We propose a network controlled spectrum access scheme where users behave collaboratively to optimize spectrum allocation for the entire network. We develop a graph-theoretical model to characterize the spectrum access problem under a number of different optimization functions, and devise rules for users to utilize available spectrum while avoiding interference with their neighbors. Experimental results confirm that user collaboration yields significant benefits (as much as 50% improvement) in opportunistic spectrum access.

Collaboration and fairness in opportunistic spectrum access