Aggressive RF Circuit Reduction Techniques in Millimeter Wave Cellular Systems

• 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 beam-ports are reduced relative to the array ports resulting in the removal of a bank of RF switches and its associated biasing network. We conducted full electromagnetic 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 ratio (SINR) of a 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 include 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 realizations of the mmWave RF front-ends, while still maintaining highly desirable and useful operational characteristics.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Kommunikationssystem (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Communication Systems (hsv//eng)

Nyckelord

Rotman lens arrays

Millimeter-wave systems

Beamforming

Maximum-ratio combining

RF switching

Publikations- och innehållstyp

kon (ämneskategori)

ref (ämneskategori)