Capacity-Aware Multi-User Massive MIMO for Heterogeneous Cellular Network

We consider a heterogeneous network (HetNet) where data are delivered from multi-users to a macro-cell base station (MBS) with the help of massive antenna small-cell base stations (SBSs). It is assumed that both the MBS and the small-cell base stations (SBSs) are equipped with massive arrays, while all mobiles users (macro-cell and small-cell users) have single antenna. By allowing users with simple omnidirectional antennas to relay their data through a highly directional massive antenna array and focus their transmission in the direction of the MBS, large increases in energy and spectral efficiency can be achieved. Each SBS performs maximum ratio combining (MRC) to detect data from its mobile users and a capacity-aware scheme to beamform the received data to the MBS. The performance evaluation in terms of the symbol error rate (SER) and the ergodic system capacity shows that the proposed capacity-aware HetNet achieves better performance than traditional Eigen-beamforming and requires considerably less computational complexity.