BER performance evaluation of conventional OFDM system and Wavelet Packet Modulator System in 4G LTE

Abstract

The increased demand for high data rate in the 21st century has necessitated a more efficient method of data spectrum usage. Conventional OFDM is a Multi-Carrier Modulation (MCM) scheme, capable of providing higher data rate, which is traditionally implemented using Fast Fourier Transform (FFT) for modulation and demodulation, which has a few drawbacks including the inefficient use of the available spectrum due to the addition of cyclic prefix, and higher power requirement (1). Thus, there is need for an MCM system that overcomes these drawbacks. Wavelet Packet Modulator (WPM) based system eliminates the above drawbacks, as it does not require the addition of cyclic prefix. It provides far better orthogonality of adjacent channel signals because wavelet bases are much longer in length than the duration of a symbol and can overlap in the time domain without losing their orthogonality. In this work MATLAB® tool is used to simulate both FFT OFDM and WPM systems, and to analyze their performance using Bit Error Rate (BER) as a metric. These outputs are evaluated in the presence of AWGN for different constellations of Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM) is implemented in the simulation.