On Downlink Network MIMO under a Constrained Backhaul and Imperfect Channel Knowledge

Next generation mobile communications systems will most likely employ network MIMO in order to mitigate inter-cell interference and improve system fairness and spectral efficiency. Critical issues of such schemes are, however, the large extent of backhaul infrastructure required for the information exchange between cooperating base stations, and the availability of channel knowledge at transmitter and receiver. In this paper, we consider a cooperative downlink transmission under a constrained backhaul, limited channel knowledge at base station and terminal side, and a per-antenna power constraint. We derive inner capacity bounds for different cooperation schemes through uplink/downlink duality and provide numerical results showing the superiority of certain cooperation schemes in terms of rate/backhaul tradeoff for different interference scenarios.