A Simple Method of Transmitting Stream Adaptation for Fixed-Matrix-Size Precoding on MU-MIMO Transmission
During the operation of MultiUser Multiple-Input Multiple Output (MU-MIMO) algorithms, some antennas of BS or UEs may neither transmit nor receive signals due to the long distance or unexpected damages. Therefore, the BS cannot obtain the Channel State Information (CSI) from/to these antennas. Without these CSI, the performance of algorithm is degraded. The authors call this effect as 'Broken Antenna Effect (BAE).' To cope with this issue, this paper proposes a process to regularize the channel matrix by replacing the missing CSI with zero(s) and setting nonzero values to diagonal elements.