High-Order Modulation Large MIMO Detector Based on Physics-Inspired Methods

TL;DR

HOPbit is a physics-inspired MIMO detector that transforms detection into a higher-order optimization problem, enabling rapid convergence and near-optimal performance for high-order modulations in large MIMO systems.

Contribution

It introduces a novel approach that maintains gray-coded mapping while solving HUBO problems with p-bits, improving convergence and accuracy over existing methods.

Findings

HOPbit outperforms ParaMax by several orders of magnitude in BER.

HOPbit achieves lower BER than traditional detectors.

It effectively handles high-order modulations in large MIMO systems.

Abstract

Applying quantum annealing or current quantum-/physics-inspired algorithms for MIMO detection always abandon the direct gray-coded bit-to-symbol mapping in order to obtain Ising form, leading to inconsistency errors. This often results in slow convergence rates and error floor, particularly with high-order modulations. We propose HOPbit, a novel MIMO detector designed to address this issue by transforming the MIMO detection problem into a higher-order unconstrained binary optimization (HUBO) problem while maintaining gray-coded bit-to-symbol mapping. The method then employs the simulated probabilistic bits (p-bits) algorithm to directly solve HUBO without degradation. This innovative strategy enables HOPbit to achieve rapid convergence and attain near-optimal maximum-likelihood performance in most scenarios, even those involving high-order modulations. The experiments show that HOPbit surpasses ParaMax by several orders of magnitude in terms of bit error rate (BER) in the context of 12-user massive and large MIMO systems even with computing resources. In addition, HOPbit achieves lower BER rates compared to other traditional detectors.