Ant Colony Optimization of Fuzzy Logic Based Approach for Dynamic Spectrum Access in Cognitive Radio Network

One of the emerging areas in the field of next generation wireless network is the Cognitive Radio Network (CRN). The traditional spectrum access approach leads to vast underutilization of the radio spectrum assigned to primary (licensed) users. The dynamic spectrum access is the most suitable approach to achieve finest spectrum utilization. The dynamic spectrum access technique allows the secondary (unlicensed) users to sense and use the available spectrum opportunistically, hence also known as opportunistic spectrum access. In this paper, an approach using a Sugeno type Fuzzy Logic System (FLS) to control the spectrum access has been proposed. Three parameters: spectrum utilization efficiency of the secondary user, its degree of mobility, and its distance to the primary userare used to describe the system. The output of the FLS gives the spectrum band accessing possibility for secondary users and the user with the highest possibility will be assigned the existing spectrum band. The Sugeno type FIS proposed in this work has been optimized using Ant Colony Optimization (ACO) technique. The ACO optimized Sugeno FIS has also been compared favorably with Sugeno type FLS for dynamic spectrum access and with the Mamdani based FLS already reported in[1].