e up-conversion/ down-conversion of the band-pass signal transmission. Ideally, the spectrum of the oscillator is expected to have an impulse at the frequency of oscillation with no frequency compo- nents elsewhere. However, the spectrum of a practical oscillator's output does have random variation around the oscillation frequency due to phase noise. The impact of local oscillator phase noise on the performance of an OFDM system has been extensively studied in the lit- erature [30]. It has been shown that phase noise may have significant effects on OFDM sig- nals with small subcarrier spacing (i.e., large OFDM symbol duration in time). Long symbol duration is required for implementing a long guard interval that can mitigate long multipath delay in single-frequency operation without excessive reduction of data through- put. The studies suggest that phase noise in OFDM systems can result in two effects: a common subcarrier phase rotation on all the subcarriers and a thermal-noise-like subcarrier de-orthogonality. The common phase error, that is, constellation rotation, on all the demodulated subcarriers, is caused by the phase noise spectrum from DC (zero frequency) up to the frequency of sub- carrier spacing. This low-pass effect is due to the long integration time of the OFDM sym- bol duration. This phase error can in principle be corrected by using pilots within the same symbol (in-band pilots). The phase error causes subcarrier constellation blurring rather than rotation. It results from the phase noise spectrum contained within the system bandwidth. This part of the phase noise is more crucial, since it cannot be easily corrected. The SNR New Radio Access Physical Layer Aspects (Part 1) 329 degradation caused by the common phase error can be quantified as SNRphase-rotation = [I(a),BAf] where Af is the subcarrier spacing, B denotes the upper bound of the phase noise spectral mask, a is the ratio of the equivalent spectrum mask noise bandwidth and the subcarrier spacing, and I(a) = with I(0.5) = 0.774, I(1) = 0.