Confidential Communication in C-RAN Systems with Infrastructure Sharing

This work considers a Cloud Radio Access Network (C-RAN) architecture in which the Radio Units (RUs) are shared among multiple operators or are managed by a separate infrastructure provider, while mobile users and cloud processor belong to the given service provider. In order to account for the resulting privacy concerns, the strict constraint is imposed that the RUs should only be able to infer a fraction of the information about the mobiles' messages that vanishes with the transmission blocklength. The largest achievable rate under this constraint, or secrecy capacity, is characterized for a two-cell Gaussian model and for a multi-cell circular Wyner model.