Spectrally-Precoded OFDM for 5G Wideband Operation in Fragmented   sub-6GHz Spectrum
  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. 
Renaud-Alexandre Pitaval, Branislav M. Popovi\'c, Medhat Mohamad,   Rickard Nilsson, Jaap van de Beek
cs.IT math.IT