Abstract:
In this article, a method called offset modulation (OM-OFDM) is proposed to control the peak-to-average power ratio
(PAPR) of an orthogonal frequency division multiplexing (OFDM) signal. The theoretical bandwidth occupancy of the
proposed offset modulated signal is derived. Using these bandwidth occupancy results, a closed-form theoretical bit
error rate (BER) expression for an offset modulated transmission is derived and validated. Thereafter, a BER comparison
between OM-OFDM and OFDM at a PAPR value of 13 dB shows that both methods offer similar BER characteristics for
frequency selective fading channel conditions. The OM-OFDM method in addition is able to accurately control the
PAPR of a transmission for a targeted BER. The authors have further proposed a newly applied power performance
decision metric, which can be used throughout the PAPR field, in order to compare various methods. By using this
power performance decision metric, the authors show that OM-OFDM offers between 4 dB–1.2 dB (60.34%–24.6%)
and 4.1 dB–1.2 dB (60.8%–23.6%), net power performance gain (at a BER of 10−4) when compared to a clipped OFDM,
OFDM, tone reserved (TR) OFDM and an active constellation extended (ACE) OFDM transmission in a frequency
selective fading channel. Finally, by using a complementary cumulative distribution function (CCDF), the OM-OFDM
method is shown to offer between 3.2 dB and 2 dB PAPR reduction (at a CCDF of 10−1) when compared to an OFDM,
TR, clipped, and ACE OFDM transmission.
Description:
This work is currently being patented by the University of Pretoria. Both
authors are inventors on the patent, with the University of Pretoria holding the
patent rights. This paper is based on work, for which the author has been
awarded a PhD at the University of Pretoria. The necessary permissions have
been obtained to publish such material.
