OFDM Technique for Multi - carrier Modulation ( MCM ) Signaling

AIT, Bangalore, India UVCE, Bangalore, India Corresponding Author: H. Umadevi ___________________________________________________________________________ Abstract OFDM is novel multicarrier modulation (MCM) technique. It has strong advantage of being a generic transmission scheme whose actual characteristics can be widely customized to fulfill several requirements and constraints of an advanced communication system. It adopts wavelet packet function as carriers which have the characteristic of good orthogonality and time-frequency localization. It can be seen from both theoretical analysis and software simulation that multi-carrier modulation and demodulation technique based on wavelet packet transform has unique advantage and great potential in improving the performance of communication system. This paper demonstrates the operation of a Wavelet Packet based multi-carrier modulation (WP-MCM) scheme. The wavelet packets are derived from multistage tree-structured paraunitary filter banks by choosing the right tree structure which would minimize the bit error between the desired and received signal for a particular channel condition. The performance of the system is simulated and analyzed for the AWGN channel. Through simulation results, we demonstrate the efficacy and the flexibility of the proposed wavelet packet based mechanism. The Bit Error rate (BER) performance is shown to be comparable, and even at times better, to conventional Fourier based OFDM. Comparison of different family of wavelets has been carried out and Meyer wavelet seems to be the most suitable wavelet through simulation results. __________________________________________________________________________________________