Two-Stage Channel Feedback for Beamforming and Scheduling in Network MIMO Systems
This paper proposes an efficient two-stage beamforming and scheduling algorithm for the limited-feedback Cooperative Multi-Point (CoMP) systems. The system includes multiple base-stations cooperatively transmitting data to a pool of users, which share a rate-limited feedback channel for sending back the Channel State Information (CSI). The feedback mechanism is divided into two stages that are used separately for scheduling and beamforming. In the first stage, the users report their best channel gain from all the base-station antennas and the basestations schedule the best user for each of their antennas. The scheduled users are then polled in the second stage to feedback their quantized channel vectors.