  In this paper, a dynamic hybrid active-passive reconfigurable intelligent
surface (HRIS) is proposed to further enhance the massive
multiple-input-multiple-output (MIMO) system, since it supports the dynamic
placement of active and passive elements. Specifically, considering the impact
of the hardware impairments (HWIs), we investigate the channel-aware
configuration of the receive antennas at the base station (BS) and the
active/passive elements at the HRIS to improve the reliability of system. To
this end, we investigate the average mean-square-error (MSE) minimization
problem for the HRIS-aided massive MIMO system by jointly optimizing the BS
receive antenna selection matrix, the reflection phase coefficients, the
reflection amplitude matrix, and the mode selection matrix of the HRIS under
the power budget of the HRIS. To tackle the non-convexity and intractability of
this problem, we first transform the binary and discrete variables into
continuous ones, and then propose a penalty-based exact block coordinate
descent (BCD) algorithm to solve these subproblems alternately. Numerical
simulations demonstrate the great superiority of the proposed scheme over the
conventional benchmark schemes.
