Due to the swift progress in wireless devices and their use, the previous decade has proved to be illustrious towards wireless broadcasting spectrum. The concept of cognitive radio (CR) is projected to tackle the problem of spectrum competence. The unremitting development of wireless communications, particularly mobile networks creates usable spectrum increasingly precious. The capacity to use both licensed and unlicensed inactive spectrums would result in incredible cost savings or incremental profits. In this paper, we propose a simulink based model to sense the spectrum by using fundamental power finding method. We analyze the channel residence by evaluating the received signal strength with a known threshold rate. If the signal is modulated (analog or digital), energy level will be very high when compared to the average noise signal, from which we can conclude that channel is occupied by some primary users else it is at leisure. We perform this for various analog and digital modulations among the variety of channels like additive white Gaussian noise (AWGN), Rayleigh and Rician and compare the bit error rate (BER).

CR-simulink, various channels, various modulations.