Performance analysis and interference cancellation for heterogeneous network with massive MIMO

Heterogenous network and massive MIMO can significantly enhance spectral and energy efficiency of wireless networks and therefore have attracted much attention. In this paper, we analyze the performance of a downlink heterogenous network where a macro base station (BS) is equipped with a large number of antennas. Lower bounds on ergodic rates for macro and pico users are derived when macro and pico BSs employ zero forcing and matched filter precoding matrix, respectively. To utilize high degrees of freedom introduced by massive MIMO, interference cancellation can be used to further improve the network performance. In this way, the macro BS can project signals for macro users to the null space of interference channels from macro BS to pico users. To maximize the overall network transmission rate by selecting the interference-free pico users, an algorithm based on statistical channel state information is developed, which can reduce the backhaul overhead. The analytical results are confirmed and the performance of the proposed algorithm is demonstrated by computer simulation.