In this paper, we introduce a novel hybrid multiuser multiple-input multiple-output (MU-MIMO) architecture, with an emphasis on aggressive millimeter-wave (mmWave) hardware reduction methods, omitting the beam selection stage. We propose a simplification in a 28 GHz Rotman lens, where the number of its beam-ports are reduced relative to the array ports resulting in the removal of a bank of RF switches and associated biasing network. We conducted full electromagnetic (EM) characterization of imperative lens defects and precisely quantify the expected loss. For the first time, it is shown that the beam- port decimation greatly reduces the total EM aberrations, and consequently increases the focusing capability of the lens. With maximum-ratio (MR) baseband processing, we study uplink signal-to-interference-plus-noise of user terminal, and evaluate the sum spectral efficiency performance of the proposed system assuming a 28 GHz double-directional propagation channel. The performance of the proposed system is compared with the classical system including the beam selection network. Although the performance of the proposed architecture is sub-optimal relative to the conventional case, we demonstrate that it greatly simplifies the practical realization of the mmWave RF front-ends, while still maintaining highly desirable and useful operational characteristics.
|Title of host publication||2019 16th International Symposium on Wireless Communication Systems (ISWCS)|
|Publisher|| IEEE |
|Publication status||Published - 21 Oct 2019|