Digital Modulation & Detection Techniques Using FRFT Basis Functions

-Recently the technological developments in digital modulation techniques have resulted in significant reduction in bit error and computational complexity in their realization. However, researchers are coming up with new techniques to meet the challenges encountered in digital modulation and detection. Amplitude modulation, frequency modulation, phase modulation and also combination of these have been employed to represent / distinguish ones and zeros or even several combinations of groups of ones and zeros of a digital bit stream. At the same time, conventional transmitters and receivers are being replaced with programmable hardware such as general purpose PC / special purpose digital signal processor referred to as dedicated software defined radio (SDR) kit. Except for the antenna section, the entire conventional radio functionality may be replaced with a program developed on special purpose hardware. SDR is thus evolving to be a promising solution for these challenges such as interoperability, global seamless connectivity encountered in wireless communication. While conventional digital modulation techniques such as Quadrature Amplitude Modulation (QAM) and orthogonal frequency division multiplexing (OFDM) employ orthogonal set of basis functions of Fourier Transform, (FT), thought process is going on to take into account dynamic characteristics of the communication channel while developing channel modeling and digital modulation techniques. In this paper an attempt is made to present a digital modulation technique that employ chirp signal which is basis function of Factional Fourier Transform (FRFT) to distinguish various bit combination in digital signal transmission followed by computationally less intensive demodulation technique based on Teager energy measurement. Keywords--Factional Fourier Transform, Software Defined Radio, Digital Modulation, Teager Energy Operator