This paper investigates performance degradation of conventional Orthogonal Frequency Division Multiplexing (OFDM) and Discrete Wavelet Transform based OFDM (DWT-OFDM) systems when the signals are passed through a nonlinear High Power Amplifier (HPA) and fading channel. In the case of DWT-OFDM, several wavelets such as Daubechies, Symlet and Biorthogonal are evaluated. | International Journal of Computer Networks and Communications Security C , , DECEMBER 2013, 316–323 Available online at: ISSN 2308-9830 N C S Performance Assessment of DFT-OFDM and DWT-OFDM Systems in the Presence of the SSPA and Fading Channel Abdolreza Kiani1 and Soheila Mousavi2 1, 2 Department of Electrical Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran E-mail: 1ab2rezakiani@, ABSTRACT This paper investigates performance degradation of conventional Orthogonal Frequency Division Multiplexing (OFDM) and Discrete Wavelet Transform based OFDM (DWT-OFDM) systems when the signals are passed through a nonlinear High Power Amplifier (HPA) and fading channel. In the case of DWT-OFDM, several wavelets such as Daubechies, Symlet and Biorthogonal are evaluated. Simulation results in terms of PAPR, PSD, and Bit Error Rate (BER) show that DWT-OFDM is more robust against interference and multipath effects compared to DFT-OFDM, and increasing the length of the basis function improves BER and PAPR. Keywords: DFT-OFDM; DWT-OFDM; BER; PAPR; High Power Amplifier. 1 INTRODUCTION Multicarrier Modulation (MCM) is an efficient modulation scheme which divides the incoming high rate data into lower rate data. The duration of symbols is increased by simultaneously transmitting N data symbols which leads to robustness against channels fading, impulsive noise, and Inter Symbol Interference (ISI). OFDM is a multicarrier scheme commonly used nowadays. OFDM has been widely adopted and standardized across the world. A number of applications and standards which use OFDM include Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB), WiFi (IEEE ), World Wide Interoperability for Microwave Access (WiMAX-IEEE ), Ultra Wide Band Wireless Personal Area Network (UWB Wireless PAN-IEEE ) and Mobile Broadband Wireless Access (). Inverse Fast Fourier Transform (IFFT)
