Low complexity DOA estimation using AMP with unitary transformation and iterative refinement

Mao, Yiwen; Luo, Man; Gao, Dawei; Guo, Qinghua

doi:10.1016/j.dsp.2020.102800

Cited by 11 publications

(1 citation statement)

References 26 publications

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“…Inspired by [16], the work in [17] discovered that AMP can still work well for a general system transfer matrix when a unitary transform of the original model is used, where the unitary transformation is used to diagonalize the system transfer matrix, e.g., the unitary matrix for transformation can be the conjugate transpose of the left singular matrix of a general system transfer matrix, or it can be simply a discrete Fourier transform (DFT) matrix for a circulant system transfer matrix. This variant to AMP is called UTAMP for convenience, which has been developed for low complexity robust sparse Bayesian learning [18], low complexity robust bilinear recovery [19], low complexity robust inverse synthetic aperture radar (ISAR) imaging with high Doppler resolution [20], low complexity direction of arrival (DOA) estimation [21], etc. It will be shown in this paper that UTAMP is well suitable for OTFS because the channel matrix in the DD domain is a block circulant matrix with circulant block (BCCB), which can be efficiently diagonalized using the 2D fast Fourier transform (FFT) algorithm.…”

Section: Introductionmentioning

confidence: 99%

Iterative Detection for Orthogonal Time Frequency Space Modulation with Unitary Approximate Message Passing

Yuan

Liu

Yuan

et al. 2020

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The orthogonal time frequency space (OTFS) modulation has emerged as a promising modulation scheme for high mobility wireless communications. To harvest the time and frequency diversity promised by OTFS, some promising detectors, especially message passing based ones, have been developed by taking advantage of the sparsity of the channel in the delay-Doppler domain. However, when the number of channel paths is relatively large or fractional Doppler shift has to be considered, the complexity of existing detectors is a concern, and the message passing based detectors may suffer from performance loss due to the short loops involved in message passing. In this work, we investigate the design of OTFS detectors based on the approximate message passing (AMP) algorithm. In particular, AMP with unitary transformation (UTAMP) based detectors are developed, which enjoy the structure of the channel matrix and allow efficient implementation, e.g., by exploiting the property of block circulant matrix with circulant block (BCCB), the complexity of the UTAMP-based detector per symbol is in the order of the logarithm of OTFS block length. In addition, the estimation of noise variance is incorporated into the UTAMPbased detectors (while existing detectors assume perfect noise variance). Thanks to the robustness of UTAMP relative to AMP, the UTAMP-based detectors are able to deliver much better performance, and outperform state-of-the-art detectors significantly. The investigations are also extended to iterative joint detection and decoding in a coded OTFS system, where the OTFS detectors are integrated into a powerful turbo receiver, leading to a considerable performance gain.

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