Efficient spectrum sharing and power control in cognitive radio networks

Cognitive radio technology solves the spectrum under utilization problem by enabling the secondary users access the spectrum holes opportunistically. In this paper, we are interested in how to share the spectrum holes among the secondary users, with the objective of maximizing the total spectrum utilization. We present a cross-layer design including spectrum sharing and power control. Spectrum sharing determines which neighbor a node will communicate with and which channel this communication will take place; power control decides which power level a node will use. We propose a Binary Integer Linear Programming (BILP) formulation, and use LINGO to find the optimal solution. With the assumption that all nodes transmit at a same power level, we find that there exists an optimal common power level at which the total spectrum utilization is maximized. Numerical results demonstrate that, using the optimal common power level not only improves the total spectrum utilization, but also reduces the complexity of the BILP problem.