Rapid Phase Ambiguity Elimination Methods for DOA Estimator via Hybrid Massive MIMO Receive Array

TL;DR

This paper introduces rapid phase ambiguity elimination methods for DOA estimation in hybrid massive MIMO arrays, achieving single time-slot operation, low complexity, and near-CRLB accuracy.

Contribution

The paper proposes three novel methods—Max-RP, Max-RP-QI, and Root-MUSIC plus Max-RP-QI—for fast phase ambiguity removal in hybrid MIMO arrays, with improved accuracy and computational efficiency.

Findings

All methods eliminate phase ambiguity in one time-slot.

Root-MUSIC plus Max-RP-QI reaches the CRLB.

Max-RP and Max-RP-QI have 2-4 dB performance loss compared to CRLB.

Abstract

For a sub-connected hybrid multiple-input multiple-output (MIMO) receiver with $K$ subarrays and $N$ antennas, there exists a challenging problem of how to rapidly remove phase ambiguity in only single time-slot. First, a DOA estimator of maximizing received power (Max-RP) is proposed to find the maximum value of $K$-subarray output powers, where each subarray is in charge of one sector, and the center angle of the sector corresponding to the maximum output is the estimated true DOA. To make an enhancement on precision, Max-RP plus quadratic interpolation (Max-RP-QI) method is designed. In the proposed Max-RP-QI, a quadratic interpolation scheme is adopted to interpolate the three DOA values corresponding to the largest three receive powers of Max-RP. Finally, to achieve the CRLB, a Root-MUSIC plus Max-RP-QI scheme is developed. Simulation results show that the proposed three methods eliminate the phase ambiguity during one time-slot and also show low-computational-complexities. In particular, the proposed Root-MUSIC plus Max-RP-QI scheme can reach the CRLB, and the proposed Max-RP and Max-RP-QI are still some performance losses $2dB\thicksim4dB$ compared to the CRLB.