  Localization is envisioned as a key enabler to satisfy the requirements of
communication and context-aware services in the fifth/sixth generation (5G/6G)
communication systems. User localization can be achieved based on delay and
angle estimation using uplink/downlink pilot signals. However, hardware
impairments (HWIs) (such as phase noise and mutual coupling) distort the
signals at both the transmitter and receiver sides and thus affect the
localization performance. While this impact can be ignored at lower frequencies
with less severe HWIs, and less stringent localization requirements, modeling
and analysis efforts are needed for high-frequency bands to assess degradation
in localization accuracy due to HWIs. In this work, we model various types of
impairments for a mmWave multiple-input-multiple-output communication system
and conduct a misspecified Cram\'er-Rao bound analysis to evaluate HWI-induced
performance losses in terms of angle/delay estimation and the resulting 3D
position/orientation estimation error. We also investigate the effect of
individual and overall HWIs on communication in terms of symbol error rate
(SER). Our extensive simulation results demonstrate that each type of HWI leads
to a different level of degradation in angle and delay estimation performance,
and the prominent impairment factors on delay estimation will have a dominant
negative effect on SER.
