Optimal quality competition for spectrum sharing in cognitive radio networks

Cognitive radio is a new technology for improving frequency spectrum usage in wireless networks. A pivotal issue in cognitive radio is spectrum sharing, which allows primary (licensed) users to share their licensed radio frequency spectrum with secondary (unlicensed) users. In this paper, we will model the cognitive radio environment as a quality based competition. We consider the spectrum sharing problem between multiple primary users and only one secondary user. The novelty of this paper is that we formulate this problem as an oligopoly market competition and use the Cournot game (quality-based competition) to obtain the optimal spectrum allocation for the secondary user. Nash equilibrium is considered as the solution of this game. We will consider two different cases: static game in which each user can observe the adopted strategies and the payoff of others and dynamic game in which the strategy of each user is selected based on only the information obtained during the game. At the end, the stability condition for the dynamic case of spectrum sharing is investigated. Performance evaluation shows that our model results in more profits for primary users with lower offered prices for the secondary user and larger shared spectrum sizes at the expense of some stability decrease.