  We consider spectrally-precoded OFDM waveforms for 5G wideband transmission
in sub-6GHz band. In this densely packed spectrum, a low out-of-band (OOB)
waveform is a critical 5G component to achieve the promised high spectral
efficiency. By precoding data symbols before OFDM modulation, it is possible to
achieve extremely low out-of-band emission with very sharp spectrum transition
enabling an efficient and flexible usage of frequency resources.
Spectrally-precoded OFDM shows promising results for reaching 5G targets in
high-data rate enhanced mobile broadband and ultra-reliable low-latency
communications use cases. Spectral precoding is particularly efficient for
wideband transmission enabling short-time transmission, which will often
require flexible fragmented spectrum usage.
