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A novel sensing approach for the single radio frequency (RF) chain millimeter wave systems is proposed. The sensing strategy is inspired from synthetic aperture radar systems, and synthesizes a virtual array manifold vector using a single phased array over temporal measurements. The geometry of the virtual array can be controlled enabling synthesis of both a virtual uniform linear array (ULA) and a virtual sparse linear array starting from a large physical array. Moreover, the proposed sensing can be realized using conventional phased array/analog combiner. Several design parameters of the sensing scheme provide flexibility and are discussed including their impact on initial alignment. The proposed sensing approach allows for a rich set of options for inference. Candidate detection and estimation algorithms are presented and their performance is evaluated.
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Novel Active Sensing and Inference for mmWave Beam Alignment Using Single RF Chain Systems
We propose a novel sensing approach for the beam alignment problem in millimeter wave systems using a single Radio Frequency (RF) chain. Conventionally, beam alignment using a single phased array involves comparing beamformer output power across different spatial regions. This incurs large training overhead due to the need to perform the beam scan operation. The proposed Synthesis of Virtual Array Manifold (SVAM) sensing methodology is inspired from synthetic aperture radar systems and realizes a virtual array geometry over temporal measurements. We demonstrate the benefits of SVAM using Cramer-Rao bound (CRB) analysis over schemes that repeat beam pattern to boost signal-to-noise (SNR) ratio. We also showcase versatile applicability of the proposed SVAM sensing by incorporating it within existing beam alignment procedures that assume perfect knowledge of the small-scale fading coefficient. We further consider the practical scenario wherein we estimate the fading coefficient and propose a novel beam alignment procedure based on efficient computation of an approximate posterior density on dominant path angle. We provide numerical experiments to study the impact of parameters involved in the procedure. The performance of the proposed sensing and beam alignment algorithm is empirically observed to approach the fading coefficient-perfectly known performance, even at low SNR.
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- PAR ID:
- 10541828
- Publisher / Repository:
- arXiv.org
- Date Published:
- Subject(s) / Keyword(s):
- Single radio frequency chain virtual array manifold synthesis coherence interval active sensing direction of arrival hierarchical codebook Bayesian estimation
- Format(s):
- Medium: X
- Institution:
- arXiv.org
- Sponsoring Org:
- National Science Foundation
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