Multiuser-MIMO Systems Using Comparator Network-Aided Receivers With 1-Bit Quantization

TL;DR

This paper introduces a novel low-resolution multiuser MIMO receiver architecture using comparator networks with 1-bit ADCs, improving performance in terms of BER and sum rate by exploiting virtual channels and advanced estimation techniques.

Contribution

It proposes a new comparator network-aided receiver design with low-resolution ADCs, along with tailored channel estimation and detection methods that outperform conventional 1-bit MIMO systems.

Findings

Comparator networks with virtual channels outperform additional antennas in BER.

The proposed channel estimation improves sum rate performance.

Simulation confirms superior BER, MSE, and sum rate over traditional 1-bit MIMO.

Abstract

Low-resolution analog-to-digital converters (ADCs) are promising for reducing energy consumption and costs of multiuser multiple-input multiple-output (MIMO) systems with many antennas. We propose low-resolution multiuser MIMO receivers where the signals are simultaneously processed by 1-bit ADCs and a comparator network, which can be interpreted as additional virtual channels with binary outputs. We distinguish the proposed comparator networks in fully and partially connected. For such receivers, we develop the low-resolution aware linear minimum mean-squared error (LRA-LMMSE) channel estimator and detector according to the Bussgang theorem. We also develop a robust detector which takes into account the channel state information (CSI) mismatch statistics. By exploiting knowledge of the channel coefficients we devise a mean-square error (MSE) greedy search and a sequential signal-to-interference-plus-noise ratio (SINR) search for optimization of partially connected networks. Numerical results show that a system with extra virtual channels can outperform a system with additional receive antennas, in terms of bit error rate (BER). Furthermore, by employing the proposed channel estimation with its error statistics, we construct a lower bound on the ergodic sum rate for a linear receiver. Simulation results confirm that the proposed approach outperforms the conventional 1-bit MIMO system in terms of BER, MSE and sum rate.