One-Bit Successive-Cancellation Soft-Output (OSS) Detector for Uplink MU-MIMO Systems with One-Bit ADCs

Abstract

We study an uplink multiuser multiple-input multiple-output (MU-MIMO) system with one-bit analog-to-digital converters (ADCs) in which one base station (BS) with N-r receive antennas serve K users with a single antenna. For this system, the soft-output (SO) detector was recently proposed where a soft-metric (e.g., a log-likelihood ratio (LLR)) is computed from a hard-decision channel output by introducing a novel distance measure in the binary Hamming space. This makes it possible to be naturally incorporated into the state-of-the-art channel codes (e.g., low-density parity-check code or polar code). In this paper, we further improve the performance of the SO detector by exploiting a priori information (e.g., the previously decoded messages), which is called the one-bit successive-cancellation soft-output (OSS) detector. The key idea of the proposed OSS detector is that each user k's message is decoded sequentially via the associated channel decoder k in ascending order and a refined search-space is constructed using the previously decoded messages (i.e., the enhanced LLRs are generated). We then present a multiple OSS detector by taking into account a more practical scenario where the BS is equipped with multiple channel decoders. In addition, we propose an efficient way to determine a good decoding order by introducing a novel set-distance measure. Finally, simulation results demonstrate that the proposed OSS detector can significantly improve the existing SO detector for the coded MU-MIMO systems with one-bit ADCs.