Abstract
Spectral null codes has a wide range of applications,
and it has been shown that the Power Spectral
Density (PSD) of messages in Orthogonal Frequency Division
Multiplexing (OFDM) systems can be shaped to have nulls at
designed frequencies. Peak to average power ratio (PAPR) is a
common problem with OFDM, resulting in power intensive and
more expensive modulators which are not suitable for modern
mobile devices with limited battery life. The use of PAPR
reduction techniques in OFDM is crucial in order to make it
compatible with modern devices. We investigate the effect of
spectral null codes on the performance of the OFDM system.
In particular we focus on the bit error rate performance (BER)
and the PAPR performance. We show that the use of spectral
null codes has no negative impact on either the BER or PAPR
performance, as expected. We conclude that the spectral null
coding technique may be used to shape the PSD in OFDM
systems without causing any significant negative impact on
performance.