 
Summary: K. Panta and J. Armstrong: Spectral Analysis of OFDM Signals and its Improvement by Polynomial Cancellation Coding
Contributed Paper
Manuscript received July 11, 2003 0098 3063/00 $10.00 © 2003 IEEE
939
Abstract In orthogonal frequency division multiplexing
(OFDM) systems, the subcarriers are generated by an inverse
discrete Fourier transform. In the literature, the spectra of
these subcarriers are often represented by a sequence of sinc
functions of the same polarity. This is not consistent with the
intercarrier interference (ICI) cancellation properties of
polynomial cancellation coding (PCC) or similar selfICI
cancellation schemes in OFDM. This paper shows the spectra
of these subcarriers are more accurately represented by a
sequence of sinc functions with alternating polarity. It is
shown that the spectral rolloff of OFDM signals can be
improved by PCC and the resultant OOB power is much
reduced.
Index Terms Spectral Analysis, OFDM, Outofband
(OOB) power.
I. INTRODUCTION
