Linear Precoding With Low-Resolution DACs for Massive MU-MIMO-OFDM Downlink
Journal article, 2019

We consider the downlink of a massive multiuser (MU) multiple-input multiple-output (MIMO) system in which the base station (BS) is equipped with low-resolution digital-to-analog converters (DACs). In contrast to most existing results, we assume that the system operates over a frequency-selective wideband channel and uses orthogonal frequency division multiplexing (OFDM) to simplify equalization at the user equipments (UEs). Furthermore, we consider the practically relevant case of oversampling DACs. We theoretically analyze the uncoded bit error rate (BER) performance with linear precoders (e.g., zero forcing) and quadrature phase-shift keying using Bussgang's theorem. We also develop a lower bound on the information-theoretic sum-rate throughput achievable with Gaussian inputs, which can be evaluated in closed form for the case of 1-bit DACs. For the case of multi-bit DACs, we derive approximate, yet accurate, expressions for the distortion caused by low-precision DACs, which can be used to establish the lower bounds on the corresponding sum-rate throughput. Our results demonstrate that, for a massive MU-MIMO-OFDM system with a 128-antenna BS serving 16 UEs, only 3-4 DAC bits are required to achieve an uncoded BER of 10(-4) with a negligible performance loss compared to the infinite-resolution case at the cost of additional out-of-band emissions. Furthermore, our results highlight the importance of considering the inherent spatial and temporal correlations caused by low-precision DACs.

linear precoding

Bussgang's theorem

orthogonal frequency-division multiplexing

low-resolution digital-to-analog converter

Massive multiuser multiple-input multiple output

Author

Sven Jacobsson

Chalmers, Electrical Engineering, Communication and Antenna Systems, Communication Systems

Ericsson, Göteborg

Giuseppe Durisi

Chalmers, Electrical Engineering, Communication and Antenna Systems, Communication Systems

Mikael Coldrey

Ericsson, Göteborg

Christoph Studer

Cornell University

IEEE Transactions on Wireless Communications

1536-1276 (ISSN)

Vol. 18 3 1595-1609

Subject Categories

Telecommunications

Communication Systems

Signal Processing

DOI

10.1109/TWC.2019.2894120

More information

Latest update

4/8/2019 1