Capacity Optimization in Cognitive Radio Network through Power Control

Radio spectrum is limited like all natural resources, and is required to be used with improved spectral efficiency. One proposed solution is to allow unlicensed users to share underutilized licensed bands with its primary users (PU’s) without disturbing their communication. Cognitive Radio (CR) technology is the key enabling feature of this solution. CR technology enables the wireless nodes to share the available spectrum dynamically. Since each node in Cognitive Radio Network (CRN) is completely aware of its preferences and is capable of adapting its operation based on present environment, the resulting network would be highly dynamic. Each CR would try to access best available channel transmitting at maximum available power to achieve maximum transmission rates. In a nut shell, each CR would try to achieve the best for itself, creating potential interference with PU’s as well as other CR users with data rates plunging to minimum. To model, analyze and predict the behavior of CR nodes Game Theory is the most suitable tool since it urges CR users to cooperate in order to achieve better results. In this paper we have analyzed a two user CR Network sharing spectrum with PU's by controlling their transmit-power such that they can cooperate with other CR users and coexist with PU’s and their data rates can be optimized with minimum possible transmit-power. To model and analyze the given scenario a Potential Game model has been selected. The idea of applying Potential Game was originally presented in [1] that has been explained in this paper with detailed methodology and procedure. The simulation results show that the transmit-power of the CR users has converged to a steady-state and data rates have been maximized resulting in an optimized network capacity. Index Terms cognitive radio, game theory, potential games, Nash Equilibrium, power control, network capacity