Two-Stage Downlink Beamforming in MISO Multicell Networks with Limited Backhaul Signaling

A two-stage downlink beamforming design is proposed for multicell multi-input single-output channels with limited backhaul capacity and local channel state information (CSI). The first stage is to maximize the signal-to-leakage-plus-noise ratio with local CSI. Each base station (BS) then calculates the corresponding channel gains and shares them with all other BSs, which typically requires low-rate backhaul signaling. Finally, all the BSs design their beamforming vectors in pursuit of increasing the sum-rate with the shared information. Simulation results show that the proposed scheme shows the sum-rate close to that of the scheme with global CSI even without vector channel information