arXiv subjects

Zhuoxiang Ren

Publications and source records attributed to Zhuoxiang Ren.

3 recordsLinked to original sources

arXiv2024

Neural-Network-based NLOS Identification in Angular Domain at 60-GHz

This paper introduces an identification method that determines whether a millimeter-wave wireless transmission using directional antennas is being established over a line-of-sight (LOS) or a non-line-of-sight (NLOS) cluster for indoor localization applications. The proposed technique utilizes the channel power angular spectrum that is readily available from a beam training process. In particular, the behavior of five different channel metrics, namely the spatial-domain, time-domain, and frequency-domain channel kurtosis, the mean excess delay, and the RMS delay spread, is analyzed using maximum likelihood ratio and artificial neural network. A noticeable difference between LOS and NLOS clusters is observed and assessed for identification. Hypothesis testing shows errors as low as 0.01-0.02 in simulation and 0.04-0.07 in measurements at 60 GHz.

eess.SP↗

arXiv2023

Self-biased magnetoelectric Ni/LiNbO3/Ni for body embedded electronic energy harvesters

In this study, we present the fabrication and characterization of Ni/LiNbO3/Ni trilayers using RF sputtering. These trilayers exhibit thick Ni layers (10 microns) and excellent adherence to the substrate, enabling high magnetoelectric coefficients. By engineering the magnetic anisotropy of Nickel through anisotropic thermal residual stress induced during fabrication, and by selecting a carefully chosen cut angle for the LiNbO3 substrate, we achieved a self-biased behavior. We demonstrate that these trilayers can power medical implant devices remotely using a small AC magnetic field excitation, thereby eliminating the need for a DC magnetic field and bulky magnetic field sources. The results highlight the potential of these trilayers for the wireless and non-invasive powering of medical implants. This work contributes to the advancement of magnetoelectric materials and their applications in healthcare technology.

cond-mat.mtrl-sci↗

arXiv2021

Angular Clustering of Millimeter-Wave Propagation Channels with Watershed Transformation

An angular clustering method based on image processing is proposed in this paper. It is used to identify clusters in 2D representations of propagation channels. The approach uses operations such as watershed segmentation and is particularly well suited for clustering directional channels obtained by beam-steering at millimeter-wave. This situation occurs for instance with electronic beam-steering using analog antenna arrays during beam training process or during channel modeling measurements using either electronic or mechanical beam-steering. In particular, the proposed technique is used here to cluster two-dimensional power angular spectrum maps. The proposed clustering is unsupervised and is well suited to preserve the shape of clusters by considering the angular connection between neighbor samples, which is useful to obtain more accurate descriptions of channel angular properties. The approach is found to outperform approaches based on K-Power- Means in terms of accuracy as well as computational resource . The technique is assessed in simulation using IEEE 802.11ad channel model and in measurement using experiments conducted at 60 GHz in an indoor environment.

eess.SP↗