Performance analysis of QAM-modulation parameters on wavelet packet transform (WPT) and FFT-OFDM system

Abstract

In Orthogonal Frequency Division Multiplexing (OFDM) a cyclic prefix (CP) is appended to each symbol in order to mitigate the effect of Inter-Symbol-Interference (ISI). However this leads to spectral inefficiency. A perfect reconstruction using wavelet packet transmultiplexer in OFDM transceiver counters the degrading effect of ISI, and also conserves bandwidth. In this paper the BER performance comparison between the OFDM systems that utilise the conventional Discrete Fourier Transform (DFT) and Discrete Wavelet Packet Transform (DWPT) respectively is analyzed. The analysis is done for various number of modulation QAM constellation points (8 to 64), and simulated over AWGN channel. Simulation results show that the best BER performance exhibits by the WPT-OFDM system, when the number of modulation QAM is 8.