ments in the uplink (UL) and downlink (DL) waveforms: Variable subcarrier spacing (SCS) Waveform filtering/windowing for better spectrum confinement Use of Cycle Prefix-Orthogonal Frequency-Division Multiplexing (CP-OFDM) and Direct Fourier Transform-spread Orthogonal Frequency-Division Multiplexing (DFT-s-OFDM) in the UL Low peak to average power ratio (PAPR) waveforms with spectral shaping LTE waveforms use only 15 kHz SCS (with the exception of the 3.75 kHz case in NB-IoT); in NR, variable SCS is introduced. SCS is in the form of 15 X (2)H kHz, with = 0-5, covering SCS from 15 to 480 kHz. This was required to enable the following: Covering new frequencies of operation well beyond the current LTE maximum fre- quency of 6 GHz and especially mmWave frequencies, where the increased phase noise requires a higher SCS, but also the shorter channel coherence time requires shorter frames. At a given frequency, higher SCS enables shorter symbols, thus enabling lower laten- cies. Addressing higher Doppler shifts due to higher mobility (up to 500 km h-1 and higher frequencies like mmWave. Support of larger channel bandwidths with a reasonable Fast Fourier Transform (FFT) size. Waveform filtering (filtering in the frequency domain) or windowing (filtering in the time domain) has been introduced, which enables the spectrum to be better con- centrated around the allocated resource blocks (RBs). This improves both in-channel in-band emissions (IBE) but also out-of-channel emissions with a higher number of RBs resulting in better spectrum utilization (SU). In the study phase of NR, a number of filtering or windowing techniques were in competition, but as shown in Figure 12.1, once power amplifier (PA) nonlinearity occurs, the output spectrum (bottom) is dominated by the PA spectral regrowth regardless of the input waveform filtering or windowing technique used (top). Based on this, it was decided that the spectrum confinement technique would not be standardized but indirectly specified in RAN4 via IBE and SU requirements. Comp