Effects of Wall Reflection on the Per-Antenna Power Distribution of ZF-Precoded ULA for Indoor mmWave MU-MIMO Transmissions

Indoor access points (APs) with large-scale antenna arrays are commonly deployed in the vicinity of a wall, where wall reflection (WR) affects indoor electromagnetic (EM) wave propagation. In this letter, we investigate effects WR on per-antenna power distribution transmit uniform linear array (ULA) adopting zero-forcing (ZF) precoder. A new channel model is constructed to characterise impact both line-of-sight (LOS) path and millimetre (mmWave) multi-user (MU) multiple-input multiple-output (MIMO) downlink transmissions. Specifically for dual user equipment (UE) scenario, ZF precoding matrix analytically obtained verified through simulations. The ZF-precoded ULA, terms normalised maximum ratio (MPR), evaluated comparisons between our proposed pure LOS model. Our analytical numerical results reveal AP configurations (the number antennas AP-wall distance), spatial angle departure (AoD) length each user), parameters (permittivity thickness) across ULA. It found that will exacerbate uneven