  Phase-noise (PN) estimation and compensation are crucial in millimeter-wave
(mmWave) communication systems to achieve high reliability. The PN estimation,
however, suffers from high computational complexity due to its fundamental
characteristics, such as spectral spreading and fast-varying fluctuations. In
this paper, we propose a new framework for low-complexity PN compensation in
orthogonal frequency-division multiplexing systems. The proposed framework also
includes a pilot allocation strategy to minimize its overhead. The key ideas
are to exploit the coherence bandwidth of mmWave systems and to approximate the
actual PN spectrum with its dominant components, resulting in a non-iterative
solution by using linear minimum mean squared-error estimation. The proposed
method obtains a reduction of more than 2.5x in total complexity, as compared
to the existing methods. Furthermore, we derive closed-form expressions for
normalized mean squared-errors (NMSEs) as a function of critical system
parameters, which help in understanding the NMSE behavior in low and high
signal-to-noise ratio regimes. Lastly, we study a trade-off between performance
and pilot-overhead to provide insight into an appropriate approximation of the
PN spectrum.
