ISSN : 1796-2021
Volume : 3    Issue : 3    Date : July 2008

Effects of Channel Estimation Error in the Presence of CFO on OFDM BER in Frequency-Selective
Rayleigh Fading Channels
Chi-Hsiao Yih
Page(s): 10-18
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In this paper, we study the effects of channel estimation error on the bit-error-rate (BER) of
orthogonal frequency division multiplexing (OFDM) systems in frequency-selective slowly Rayleigh
fading channels. Due to the additive white Gaussian noise (AWGN) and the intercarrier interference
(ICI) caused by the residual carrier frequency offset (CFO), the channel estimation based on the
training symbols is not perfect. We characterize the performance degradation resulting from
imperfect channel state information (CSI) by deriving the BER formulas for BPSK, QPSK, 16-QAM,
and 64-QAM modulation schemes. The derived BER formulas contain no numerical integrals and
can be evaluated easily and accurately. Simulation results validate the correctness of our theoretical

Index Terms
Orthogonal frequency division multiplexing, channel estimation, carrier frequency offset,
frequencyselective Rayleigh fading, bit-error-rate, performance analysis