Finite-Alphabet Wiener Filter Precoding for mmWave Massive MU-MIMO Systems

Abstract

Power consumption of multiuser (MU) precoding is a major concern in all-digital massive MU multiple-input multipleoutput (MIMO) base-stations with hundreds of antenna elements operating at millimeter-wave (mmWave) frequencies. We propose to replace part of the linear Wiener filter (WF) precoding matrix by a finite-alphabet WF precoding (FAWP) matrix, which enables the use of low-precision hardware that consumes low power and area. To minimize the performance loss of our approach, we present methods that efficiently compute FAWP matrices that best mimic the WF precoder. Our results show that FAWP matrices approach infinite-precision error-rate and error-vector magnitude performance with only 3-bit precoding weights, even when operating in realistic mmWave channels. Hence, FAWP is a promising approach to substantially reduce power consumption and silicon area in all-digital mmWave massive MU-MIMO systems.

Finite-Alphabet MMSE Equalization for All-Digital Massive MU-MIMO mmWave Communication

“…Moreover, the development of algorithms that outperform FAME-FBS and further approach the performance of FAME-EXH at low complexity is a challenging open research direction. The finite-alphabet equalization paradigm is also applicable to downlink precoding in massive MU-MIMO mmWave systems [41] and could be used in other applications where matrix-vector products must be computed at high rates or with low power consumption-an investigation of other applications is part of ongoing research.…”