Leveraging Waveform Structure to Develop a Power Scalable AoA Estimation

Mahbuba Sheba Ullah,Ahmed Tewfik,Robert W Heath

doi:10.1109/ojcoms.2021.3134812

Mahbuba Sheba Ullah, Ahmed Tewfik + Show 1 more

Open Access

https://doi.org/10.1109/ojcoms.2021.3134812

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Abstract

In a mmWave mobile device, power consumption resulting from the high sampling rate is a primary concern for angle of arrival (AoA) estimation solutions. In this paper, we provide a power scalable solution for AoA estimation with structured waveforms in a narrowband channel. We design a set of pilot sequences that maintain orthogonality in sub-Nyquist sampling domains. We leverage the sequences’ structure to develop a variable rate decoupling algorithm to separate multiple sources at the receiver using partial knowledge about the pilots. The decoupling enables a feasible, low-complexity AoA estimation for digital architectures with flexible antenna array design. In this paper, we provide one such AoA estimation solution named ADELA for a linear antenna array design. Simulation results show that AoA estimation performance reaches the Cramer-Rao-Bounds (CRBs) for a range of SNRs. The proposed estimator with subsampling factors of 8 or less outperforms two examples of full rate virtual array AoA estimators for unknown waveforms: 2-level nested array and coprime filter bank estimators. Compared to these two examples of virtual array, our method offers an 8 times lower ADC power consumption, and a significantly lower computational complexity.

Highlights

Directional communication with antenna arrays is widely used in mmWave wireless communication
We develop a power scalable AoA estimation solution enabled by a specially designed pilot sequences
Our simulation demonstrates the advantages of pilot design with temporal structure that is leveraged to decouple the pilot sources at variable sub-Nyquist sampling speed

Summary

Introduction

Directional communication with antenna arrays is widely used in mmWave wireless communication. Angle-of-arrival (AoA) of the directional beam helps a receiver to establish and manage a reliable connection in the network [1], design precoder/combiner for massive multi-input multi-output (MIMO) applications [2], [3] and detect a target in massive automotive sensing applications [4]. We develop a power scalable AoA estimation solution enabled by a specially designed pilot sequences. The pilot design adds special structures to the pilot sequences that allows a receiver to detect and separate multiple pilot sequences even when sampled at a fraction of the Nyquist rate. The distinguishing feature of the sub-Nyquist decoupling (detection and separation) of the pilots is that it is done without full knowledge of the pilot sequences. We discuss the motivation behind the key features of our AoA estimator in mmWave applications

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