Wireless Communication System Based on OFDM System Using Wavelet Transform

Orthogonal frequency division multiplexing (OFDM) based on the inverse fast Fourier transform (iFFT) is a multi-carrier modulation (MCM) system that enables high-speed 4th generation of mobile communication such as long-term evolution (LTE). The existing OFDM scheme that maps symbols to subcarriers using an inverse fast Fourier transform (iFFT) operation uses a cyclic prefix (CP) to reduce intersymbol interference in a multipath channel, which is a disadvantage of power efficiency and spectral efficiency respectively. Therefore, this paper aims to complement the existing shortcomings and to design more efficient MCM system than the conventional iFFT-based OFDM system. So, the proposed system uses IDWT (inverse discrete wavelet transform) operation instead of iFFT operation used in conventional OFDM. A wavelet transform is an operation that filters a signal using wavelet and scaling basis functions. Next, we like to compare the bit error rate (BER), spectral efficiency, and peak to average power ratio (PAPR) performance with the conventional OFDM system through the design of OFDM system based on wavelet transform. As a result, the conventional OFDM and wavelet-OFDM show the same BER performance, and wavelet-OFDM using the discrete Meyer wavelet had the same spectral efficiency as the conventional OFDM. In addition, all systems of wavelet-OFDM based on various wavelets show the lower PAPR performance than the conventional OFDM.