A real time implementation of spectrum sensing system using software defined radio

A real time implementation of a spectrum sensing system with assured accuracy plays a key role to design a cognitive radio. In cognitive radio, spectrum sensing acts as the center which enables the need for reliable detection of signals from primary licensed radio. This paper presents a spectrum sensing system based on software defined radio (SDR), which sense the unlicensed spectrum and transmits or receives frequency in that particular frequency. Software defined radio (SDR) concept is increasing exponentially as it is highly versatile to communication systems. To improve the efficiency of the spectrum utilization, cognitive radio technique has been proposed that acts as an unlicensed user to the unused frequency bands. Here two frequency modulated (FM) signals having frequency 97MHz and 120MHz are transmitted and received by another system as well as with mobile FM receiver. The power spectral density and the spectrum of the received signals are analyzed under various signal to noise conditions. The effectiveness of the system and peak to average power ration of the received power variations are verified through simulations.