On the value of data sharing in constrained-backhaul network MIMO

This paper addresses the problem of cooperation in a multicell environment where base stations wish to jointly serve multiple users, under a constrained-capacity backhaul. Such a constraint limits, among other things, data sharing and network MIMO concepts need to be revised accordingly. More precisely, we focus on the downlink, and propose to use the backhaul to transmit several messages to each user: some are common to several transmitters and joint precoding is possible, others are private and only local precoding may be done. For the two-cell setup we derive achievable rate regions, optimizing the corresponding beamforming design. Numerical results show how this added flexibility improves performance.