Location-Aware Cross-Tier Cooperation for Massive MIMO Heterogeneous Networks

This letter presents a location-aware cross-tier cooperation (CTC) scheme for downlink heterogeneous networks (HetNets), where macro base stations (MBSs) employ massive multiple-input multiple-output (MIMO) systems, and are overlaid with dense low power BSs (LPBs). We first derive an analytical expression for the average achievable rate of a typical user equipment (UE) and then derive the area spectral efficiency (SE) and energy efficiency (EE) of the proposed HetNets. Our resutls demonstrate that: 1) the proposed CTC scheme significantly improves the data rate of edge UEs in macro cell and small cell; 2) the network SE and EE can be improved by densely deployed LPBs; 3) massive MIMO enabled MBSs are capable of significantly improving the network SE. Meanwhile, the EE of HetNets with CTC can also be highly enhanced while the number of MBS antennas is configured properly.