The transmission optimization of the massive MIMO HetNets

摘要

The two-tier cellular heterogeneous networks that macro cells with massive MIMO overlaid by dense small cells can both utilize the excessive number of antennas at the macro base station and the smaller propagation distance in small cells. To alleviate the pilot contamination between the macro base stations and improve the system performance, we propose a transmission optimization scheme using time-shifted pilots, where the interferences both during the pilots based channel estimation and data sending are analyzed. Based on this analysis, the users are selected to be severed by the small base station allocated at the edge of the macro cell, to have the better ratio of the channel gains to the inferences. The numerical results show that the proposed scheme effectively improves the data rates of the systems.