Opportunistic Communication System for the FM Band

In the last years, cognitive radio (CR) has gained great attention in the scientific community; eventhough several works has shown novel methods in the CR context there is still a wide open research area due to the lack of precision in the step- by-step implementation process and a clear performance metrics definition. This paper describes in detail a design methodology for a cognitive radio implementation looking for an opportunistic transmission in the FM band and the definition of a performance metrics based on the IEEE 802.22 standard. The CR system was finally implemented on an Ettus B210 software defined radio platform programmed over GNU Radio software. A novel energy spectrum sensing, analysis, decision and transmission algorithm were implemented and tested in order to measure the system performance. Additionally, it is worth to mention this work presents a new approach for defining the average noise floor threshold in the spectrum sensing decision process. The achieved opportunistic transmission parameters are also shown given insights and recommendations for the technology selection and the FM band in the CR environment.