  In this paper, an analytical framework for evaluating the performance of
scalable cell-free massive MIMO (SCF-mMIMO) systems in which all user
equipments (UEs) and access points (APs) employ finite resolution
digital-to-analog converters (DACs) and analog-to-digital converters (ADCs) and
operates under correlated Rician fading, is presented. By using maximal-ratio
combining (MRC) detection, generic expressions for the uplink (UL) spectral
efficiency (SE) for both distributed and centralized schemes are derived. In
order to further reduce the computational complexity (CC) of the original local
partial MMSE (LP-MMSE) and partial MMSE (P-MMSE) detectors, two novel scalable
low complexity MMSE detectors are proposed for distributed and centralized
schemes respectively, which achieves very similar SE performance. Furthermore,
for the distributed scheme a novel partial large-scale fading decoding (P-LSFD)
weighting vector is introduced and its analytical SE performance is very
similar to the performance of an equivalent unscalable LSFD vector. Finally, a
scalable algorithm jointly consisting of AP cluster formation, pilot
assignment, and power control is proposed, which outperforms the conventional
random pilot assignment and user-group based pilot assignment policies and,
contrary to an equal power transmit strategy, it guarantees quality of service
(QoS) fairness for all accessing UEs.
