  The limited fronthaul capacity is known to be one of the main problems in
cloud radio access networks (CRANs), especially in the wireless fronthaul
links. In this paper, we consider the uplink of a CRAN system, where massive
multiple-input multiple-output (MIMO) is utilized in the fronthaul link.
Considering multi-antenna user equipment (UEs) and multi-antenna remote radio
heads (RRHs), we maximize the system sum-rate by jointly optimizing the
precoders at the UEs and the quantization noise covariance matrices and
transmit powers at the RRHs. To solve the resulting nonconvex problem, an
iterative algorithm based on the majorization-minimization (MM) method is
proposed. Two schemes at the central unit are considered, namely maximum ratio
(MR) and zero-forcing (ZF) combining. Numerical results show that the sum-rate
has an asymptotic behaviour with respect to the maximum available power at RRHs
and that the MR scheme goes to its asymptote faster than the ZF scheme.
