A Digital Radio System for TV White Spaces with Frequency and Transmission Bit Rate Agility

In this paper, we have proposed the method to maintain the performance of the radio system, even after switching the order of modulation scheme and the frequency of operation, for TV white space using LabVIEW and USRP. It operates within 470-806 MHz. At each frequency, SNR and BER are calculated for BPSK, QPSK and 8-PSK and these calculated values are supplied to the transmitter which helps it to choose the proper gain of power amplifier so that BER will be constant even after switching of transmitter from lower to higher order modulation scheme and vice versa. This concept provides an additional feature to the Cognitive Radio operated in TV white spaces.