Digital Signal Processing 20 (2010) 1687–1696 Contents lists available at ScienceDirect Digital Signal Processing www.elsevier.com/locate/dsp BER of OFDM with diversity and pulse shaping in Rayleigh fading environments Khoa N. Le a,∗ , Kishor P. Dabke b a School of Engineering, Building XB, Penrith South DC, University of Western Sydney, Locked Bag 1797, NSW 1797, Australia b Department of Electrical and Computer Systems Engineering, Monash University, Clayton Campus, Melbourne, Australia article info abstract Article history: Available online 30 March 2010 Keywords: OFDM Inter-carrier interference power Maximal ratio combining diversity Rayleigh fading Pulse shaping This paper derives the bit error rate (BER) of Orthogonal Frequency Division Multiplex- ing (OFDM) systems with pulse shaping for ICI reduction employing Lth-order maximal ratio combining (MRC) diversity in Rayleigh fading environments. The probability density function of the signal-to-interference ratio per bit γ in the presence of the total average inter-carrier interference (ICI) power P ICI is also derived. Simulation results are given and discussed. Crown Copyright  2010 Published by Elsevier Inc. All rights reserved. 1. Introduction OFDM has recently attracted a large amount of research work because of its robustness, diversity and high bit rates [17,3]. However, the only major drawback of OFDM systems is the presence of ICI which severely degrades OFDM system performance [6,8,7], especially in multi-path fading environments. Analytical BER analysis of π /4-differential quadrature phase shift keying (DQPSK) OFDM with carrier frequency offset over frequency-selective fast fading channels was given in [18]. However, the pdf of ICI power with and without selective diversity was not considered. An inter-carrier interference cancellation method with frequency diversity for OFDM systems was proposed in [19] which showed that diversity can be effectively employed to reduce negative effects of ICI. Trade-offs between diversity and multiplexing were briefly studied in [16]. A decision-feedback equalisation scheme with transmit beamforming was reported in [9]. Diversity analysis for frequency-selective multiple input multiple output (MIMO)-OFDM systems with general spatial and a temporal correlation model were performed in [13]. Transmit diversity was shown to be able to reduce the complexity of signal detection in OFDM systems [5]. One of the many methods which can be used to improve system performance is to employ linear diversity methods such as MRC and selective combining (SC) which were shown to be effective and efficient [10]. Work on using diversity techniques has been reported in the literature to show their effectiveness. Theoretical framework on SC and its performance can be found in [20,21]. Performance of a triple-branch hybrid-threshold system was studied in [14] using selection and maximal ratio combining techniques over Nakagami-m fading channels. MRC was employed to improve performance of code division multiple access (CDMA) systems with higher accuracy than previous methods [1]. Spatial selection combining was employed to improve performance of decode-forward relaying systems [4]. A new maximal-ratio eigen-combining technique was also successfully employed for smart array antennas in [15]. The BER of quadrature sub-branch hybrid systems was studied in [23] using selection and maximal ratio combining techniques in Rayleigh fading channels. The effectiveness of differential binary phase shift keying modulation in non-selective Rayleigh fading channels using maximal ratio combining was also * Corresponding author. E-mail addresses: lenkhoa@gmail.com (K.N. Le), Kishor.Dabke@eng.monash.edu.au (K.P. Dabke). 1051-2004/$ – see front matter Crown Copyright  2010 Published by Elsevier Inc. All rights reserved. doi:10.1016/j.dsp.2010.03.015