PHY4 – Propagation and channels

Thursday, 8 June 2023, 16:00-17:30, Room G2

Session Chair: Thomas Wilding (Graz University of Technology, Austria)

Efficient Ray-Tracing Channel Emulation in Industrial Environments: An Analysis of Propagation Model Impact
Gurjot Singh Bhatia (Université Paris-Saclay, Laboratoire Des Signaux et Systèmes, France & SIRADEL, France); Yoann Corre (SIRADEL, France); Marco Di Renzo (CNRS & Paris-Saclay University, France)
Industrial environments are considered to be severe from the point of view of electromagnetic (EM) wave propagation. When dealing with a wide range of industrial environments and deployment setups, ray-tracing channel emulation can capture many distinctive characteristics of a propagation scenario. Raytracing tools often require a detailed and accurate description of the propagation scenario. Consequently, industrial environments composed of complex objects can limit the effectiveness of a raytracing tool and lead to computationally intensive simulations. This study analyzes the impact of using different propagation models by evaluating the number of allowed ray path interactions and digital scenario representation for an industrial environment. This study is realized using the Volcano ray-tracing tool at frequencies relevant to 5G industrial networks: 2 GHz (midband) and 28 GHz (high-band). This analysis can help in enhancing a ray-tracing tool that relies on a digital representation of the propagation environment to produce deterministic channel models for Indoor Factory (InF) scenarios, which can subsequently be used for industrial network design.

Depolarisation Model for a BAN Indoor Scenario
Manuel Ferreira (ESTSetúbal/Polytechnic Institute of Setúbal, Portugal); Filipe Cardoso (ESTSetubal/Polytechnic Institute of Setubal and INESC-ID, Portugal); Slawomir Ambroziak (Gdańsk University of Technology Digital Technologies Center, Gdańsk, Poland); Mariella Särestöniemi (Erkki Koiso-Kanttilan katu 1 & Center for Wireless Communication, University of Oulu, Finland); Kenan Turbic (Fraunhofer HHI, Germany); Luis M. Correia (IST/INESC-ID – University of Lisbon & INESC, Portugal)
In this paper, an analysis of depolarisation in Body Area Networks for Body-to-Infrastructure communications based on a measurement campaign in the 5.8 GHz band in an indoor environment is performed. Measurements were made with an offbody antenna transmitting linearly polarised signals and dualpolarised receiving antennas carried by the user on the body. A Normal Distribution with a mean of 2.0 dB and a standard deviation of 4.3 dB is found to be the best fit for modelling crosspolarisation discrimination. The average correlation between the signals received by the orthogonally polarised antennas is below 0.5, showing that polarisation diversity can be used. A model is proposed for the average value of the standard deviation of the cross-polarisation discrimination ratio as a function of the transmitted polarisation, the mobility of users and link dynamics.

Impact of Array Configuration on Head-Mounted Display Performance at mmWave Bands
Alexander Marinšek (KU Leuven, Belgium & University of Ljubljana, Slovenia); Xuesong Cai (Lund University, Sweden); Lieven De Strycker (KU Leuven, Belgium); Fredrik Tufvesson (Lund University, Sweden); Liesbet Van der Perre (KU Leuven, Belgium)
Immersing a user in life-like extended reality (XR) scenery using a head-mounted display (HMD) with a constrained form factor and hardware complexity requires remote rendering on a nearby edge server or computer. Millimeter-wave (mmWave) communication technology can provide sufficient data rate for wireless XR content transmission. However, mmWave channels exhibit severe sparsity in the angular domain. This means that distributed antenna arrays are required to cover a larger angular area and to combat outage during HMD rotation. At the same time, one would prefer fewer antenna elements/arrays for a lower complexity system. Therefore, it is important to evaluate the trade-off between the number of antenna arrays and the achievable performance to find a proper practical solution. This work presents indoor 28 GHz mmWave channel measurement data, collected during HMD mobility, and studies the dominant eigenmode (DE) gain. DE gain is a significant factor in understanding system performance since mmWave channel sparsity and eigenmode imbalance often results in provisioning the majority of the available power to the DE. Moreover, it provides the upper performance bounds for widely-adopted analog beamformers. We propose 3 performance metrics – gain trade-off, gain volatility, and minimum service trade-off – for evaluating the performance of a multi-array HMD and apply the metrics to indoor 28 GHz channel measurement data. Evaluation results indicate, that 3 arrays provide stable temporal channel gain. Adding a 4th array further increases channel capacity, while any additional arrays do not significantly increase physical layer performance.

Extended NYUSIM-Based MmWave Channel Model and Simulator for RIS-Assisted Systems
Aline Habib and Israa Khaled (IMT Atlantique, France); Ammar El Falou (King Abdullah University of Science and Technology (KAUST), Saudi Arabia); Charlotte Langlais (IMT Atlantique Bretagne Pays de la Loire & Lab-STICC, France)
Spectrum scarcity has motivated the exploration of the millimeter-wave (mmWave) band as a key technology to cope with the ever-increasing data traffic. However, in this band, radiofrequency waves are highly susceptible to transmission loss and blockage. Recently, reconfigurable intelligent surfaces (RIS) have been proposed to transform the random nature of the propagation channel into a programmable and controllable radio environment. This innovative technique can improve mmWave coverage. However, most works consider theoretical channel models. In order to fill the gap towards a realistic RIS channel simulator, we extend the 3D statistical channel simulator NYUSIM based on extensive measurements to help model RISassisted mmWave systems. We validate the extended simulator analytically and via simulations. In addition, we study the received power in different configurations. Finally, we highlight the effectiveness of using RIS when the direct link is partially blocked or non-existent.

Propagation Modeling for Physically Large Arrays: Measurements and Multipath Component Visibility
Thomas Wilding and Benjamin J. B. Deutschmann (Graz University of Technology, Austria); Christian Nelson, Xuhong Li and Fredrik Tufvesson (Lund University, Sweden); Klaus Witrisal (Graz University of Technology, Austria)
This paper deals with propagation and channel modeling for physically large arrays. The focus lies on acquiring a spatially consistent model, which is essential, especially for positioning and sensing applications. Ultra-wideband, synthetic array measurement data have been acquired with large positioning devices to support this research. We present a modified multipath channel model that accounts for a varying visibility of multipath components along a large array. Based on a geometric model of the measurement environment, we analyze the visibility of specular components. We show that, depending on the size of the reflecting surface, geometric visibility and amplitude estimates obtained with a super-resolution channel estimation algorithm show a strong correspondence. Furthermore, we highlight the capabilities of the developed synthetic array measurement system.

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