Performance evaluation of massive MIMO with analog-digital hybrid processing in a real microcell environment

Massive MIMO enables the improvement on the transmission rate without increasing the burden on the signal processing by employing a large number of antennas at a base station. However, the interference cancellation with maximum ratio combining (MRC) does not sufficiently work when the circular array is used for the purpose on the circular cell, because the sidelobe level in the circular array is increased compared to the linear array. In this paper, an actual propagation channel was measured by using a wideband channel sounder with cylindrical array in 2 GHz band at a microcell environment. Moreover, we verify the effectiveness of the interference rejection when using the hybrid algorithm which employs the MRC on the analog part and zero forcing (ZF) in the digital processing part.