approach* and the *balanced random pilot strategy*.

-   For those cases in which the number of active in the network is greater than the number of available chains at a particular , a selection algorithm is proposed that aims at maximizing the minimum average sum-energy (i.e., Frobenius norm) of the equivalent channel between the and any of the active , constrained by the fact that each can only beamform to a number of less or equal than the number of available chains.

Paper organization and notational remarks
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The remainder of this paper is organized as follows. In Section \[sec:System\_model\] the proposed cell-free massive system is introduced. Different subsections are devoted to the description of the channel model, the large-scale and small-scale training phases, the channel estimation process, and the and payload transmission phases. The achievable and rates are presented in Section \[sec:Achievable\_rates\] and further developed in Appendices \[app:Appendix\_1\] and \[app:Appendix\_2\]. Section \[sec:fronthaul\_capacity\] is dedicated to the calculation of the capacity consumption of both the and fronthaul links. The pilot assignment, power allocation and quantization optimization processes are described in Sections \[sec:pilot\_assignment\] and \[sec:power allocation\_quantization\]. Numerical results and discussions are provided in Section \[sec:numerical\_results\] and, finally, concluding remarks are summarized 