An opportunistic feedback scheme for downlink coordinated scheduling/beamforming

An opportunistic feedback scheme is proposed for reducing the uplink control information feedback for the coordinated scheduling/beamforming (CS/CB) mode in the coordinated multiple point (CoMP) systems. CoMP is a promising technology for LTE-Advanced to improve the coverage and the spectral efficiency. However, the total feedback load is substantially heavy and becomes a serious problem for the practical systems. The proposed opportunistic feedback scheme can reduce the feedback load with little user throughput deterioration. In the proposed feedback scheme, in each cooperating cells set, the cells are divided into one primary cell and several assistant cells. Users in the primary cell are fairly determined to feed back according to the normalized signal to interference plus noise ratio (SINR) threshold. In the assistant cells, users who cause less interference to the primary cell are supposed to feed back. The simulation results show that the proposed scheme reduces the feedback load magnificently, while keeping the performance loss minimal.