A Low-Complexity Soft-Output wMD Decoding for Uplink MIMO Systems with One-Bit ADCs

This paper considers an uplink multiuser multipleinput-multiple-output (MU-MIMO) system with one-bit analogto-digital converters (ADCs), in which K users with a single transmit antenna communicate with one base station (BS) with Nr receive antennas. In this system, a novel MU-MIMO detection method, named weighted minimum distance (wMD) decoding, was recently proposed, as a practical approximation of maximum likelihood (ML) detector. Despite of its attractive performance, the wMD decoding has two limitations to be used in practice: i) the hard-decision outputs degrade the performance of a following channel code; ii) the computational complexity grows exponentially with the K. To address them, we first present a soft-output wMD decoding that efficiently computes soft metrics (i.e., log-likelihood ratios) from one-bit quantized observations. We then reduce the complexity of the soft-output wMD decoding by introducing hierarchical code partitioning. Simulation results demonstrate that the proposed method significantly outperforms the other MIMO detectors with a comparable complexity.