  The downlink of symmetric Cloud Radio Access Networks (C-RANs) with multiple
relays and a single receiver is studied. Lower and upper bounds are derived on
the capacity. The lower bound is achieved by Marton's coding which facilitates
dependence among the multiple-access channel inputs. The upper bound uses
Ozarow's technique to augment the system with an auxiliary random variable. The
bounds are studied over scalar Gaussian C-RANs and are shown to meet and
characterize the capacity for interesting regimes of operation.
