Study of Cognitive Radio Performance in Relation to Signal to Noise Ratio and Modulation Scheme

In this paper the variation of Bit Error Rate (BER) with the order of Quadrature Amplitude Modulation (QAM) scheme and the power channel gain of different fading channels( Additive White Gaussian Noise, Rayleigh fading & Rician fading ) for different order of QAM has been compared by taking the acceptable SNR threshold in radio communication has been analyzed. The relationship between transmitter power and bit error rate has been established. As the transmitter power and BER is inversely proportional to each other the result shows that 64 QAM is better than other order of QAM for optimizing transmitter power level. It has been observed that Additive White Gaussian Noise (AWGN) channel gives better BER value and power channel gain than those for the Rayleigh and Rician fading channel.