Ising Machines' Dynamics and Regularization for Near-Optimal Large and Massive MIMO Detection

Abstract

Optimal MIMO detection has been one of the most challenging and computationally inefficient tasks in wireless systems. We show that the new analog computing techniques like Coherent Ising Machines (CIM) and Oscillator-based Ising Machines (OIM) are promising candidates for performing near-optimal MIMO detection. We illustrate a fundamental problem with using classical, optical or quantum mechanical Ising Machines for MIMO detection: the error floor problem, which is a major bottleneck to practical deployments of Ising machine-based MIMO detectors. We propose a novel regularized Ising formulation for MIMO detection that mitigates the error floor and further evolves it into an algorithm that achieves near-optimal MIMO detection. Massive MIMO systems, that have a much larger number of antennas at the Access point (AP) than at the users, allow linear detectors to be near-optimal. However, the simplified detection in these systems comes at the cost of overall throughput, which can be improved by supporting more users. We show that our methods allow us to add more transmitter antennas/users and increase the overall throughput of the cell by several folds. We further show that our methods allow us to operate using much aggressive modulation and coding schemes and hence achieve much higher throughput. We demonstrate that, for a 16 × 16 large MIMO system, our methods achieve around 2.5× more throughput in mid-SNR regime (≈ 12dB) and 2× more throughput in high-SNR regime( > 20dB) than MMSE.

Quantum Annealing for Next-Generation MU-MIMO Detection: Evaluation and Challenges

“…This section discusses the basics of QA and focuses on specifics relevant to the MIMO detection problem, with emphasis on aspects not covered in other publications. For detailed information, the reader is referred to references such as [13], [14], [18], [19].…”

“…Note that this operation will make the effective channel matrix wider for 16-QAM and higher-order modulation. The matrix Q is defined as [18]…”

“…Here we evaluate the BER of QA MIMO detection and compare it to classic detection algorithms. It should be noted that some QA MIMO-related works, e.g., [14], [18], make use of the solution obtained by a conventional detection algorithm (such as ZF) to improve the error performance of the QA approach. This work does not assume knowledge of a previous solution.…”

A Phase Model of the Bio-Inspired NbOx Local Active Memristor under Weak Coupling Conditions

“…Based on phase dynamics, it is a good idea to build an Ising computer to solve NP-hard problems. At present, there are many ways to implement the oscillator element [29][30][31][32][33][34][35][36][37][38][39][40]. However, the current oscillator implementations also have some shortcomings and problems.…”