@Bashar18b; @Boroujerdi18] cannot by applied directly when assuming the use of frequency bands. Despite its evident potential, as far as we know, besides [@Alonzo17; @Alonzo18] there is no other research work on cell-free massive systems and, furthermore, the authors of these works did not face one of the main challenges in the implementation of cooperative , that is, the fact that these systems require of a substantial information exchange between the and the via capacity-constrained fronthaul links. Moreover, they also considered the use of oversimplified channel models and precoding stages, without constraining the available number of -chains at each .

Aim and contributions
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Motivated by the above considerations, our main aim in this paper is to address the design and performance evaluation of realistic cell-free massive systems using hybrid precoders and assuming the availability of capacity-constrained fronthaul links connecting the and the . The main contributions of our work can be summarized as follows:

-   The performance of both the and of cell-free massive systems is considered with particular emphasis on the per-user rate, rather than the system sum-rate, by posing max-min fairness resource allocation problems that take into account the effects of imperfect channel estimation, power control, non-orthogonality 