  This letter focuses on the problem of pilot assignment in cell-free massive
MIMO systems. Exploiting the well-known Hungarian algorithms, two procedures
are proposed, one maximizing the system throughput, and the other one
maximizing the fairness across users. The algorithms operate based on the
knowledge of large-scale fading coefficients as a proxy for the distances
between users in the system and take into account both the uplink and downlink
performance. Numerical results show that the proposed pilot assignment
algorithms are effective and outperform the many competing alternatives
available in the literature.
