3D-MIMO codebook aided multiple user pairing scheme in LTE-Advanced systems

Two-dimensional (2D) multiple-input multiple-output (MIMO) is currently concentrated on propagation in horizontal plane, but the impact of elevation angle is not considered. However, due to the three-dimensional (3D) character of the real MIMO channel, 2D MIMO cannot achieve the optimal system throughput. A multiple-user MIMO (MU-MIMO) user pairing scheme was proposed, in which the vertical dimension was taken into consideration. In the proposed scheme, a 3D codebook based on full dimension MIMO channel was designed; then two 3D MU-MIMO user's pairing schemes are proposed combining the proposed joint and separate 3D codebook. Simulation evaluates the proposed 3D codebook aided user pairing scheme and compares with the previous 2D MU-MIMO user pairing technology. Owing to the additional spatial degree of freedom in vertical dimension, the proposed 3D MU-MIMO user pairing schemes can effectively improve the overall system performance.