Study of Realistic Antenna Patterns in 5G mmWave Cellular Scenarios

Large antenna arrays and millimeter-wave (mmWave) frequencies have been attracting growing attention as possible candidates to meet the high requirements of future 5G mobile networks. In view of the large path loss attenuation in these bands, beamforming techniques that create a beam in the direction of the user equipment are essential to perform the transmission. For this purpose, in this paper, we aim at characterizing realistic antenna radiation patterns, motivated by the need to properly capture mmWave propagation behaviors and understand the achievable performance in 5G cellular scenarios. In particular, we highlight how the performance changes with the radiation pattern used. Consequently, we conclude that it is crucial to use an accurate and realistic radiation model for proper performance assessment and system dimensioning.Comment: to be published in 2018 IEEE ICC Communications QoS, Reliability, and Modeling Symposium (ICC18 CQRM), Kansas City, USA, May 201

The Early and Middle Holocene Lithic Industries of Ifri n’Etsedda (Eastern Rif, Morocco)

Archaeological research has been carried out in the Eastern Rif (Morocco) since 1995 by a collaborative Moroccan-German research team. A major topic of the project is the transition from hunting-gathering to food production and related cultural developments. Innovations such as pottery and domesticated species appeared around 7.6 ka calBP. The cultivation of cereals and pulses is evident at that time. Two of the most important sites in the area are Ifri Oudadane and Ifri n’Etsedda. Both provide Epipaleolithic as well as Neolithic deposits. While innovative technologies such as pottery production and cultivation indicate external influences, lithic artifacts demonstrate local technological and behavioral traditions. Therefore, the study of lithic industries is crucial to understanding the nature of cultural continuity and discontinuity between the hunting-gathering and agricultural populations in the Eastern Rif. Ifri n’Etsedda provides two distinct Epipaleolithic deposits and thus offers the opportunity to study possible changes throughout the Epipalaeolithic and relationship to the later Early Neolithic (ENC). In combination with the earlier phases of Early Neolithic assemblages (ENA, ENB) at Ifri Oudadane, we are now in a better position to understand the development of early-to-mid Holocene lithic technology in the Eastern Rif. We show that the lithic record of Ifri n’Etsedda does not indicate any significant change in raw material supply, blank production, and tool distribution from the Early Epipaleolithic to the Early Neolithic B. Therefore, we argue for behavioral continuity from the Epipaleolithic to the Neolithic period. In contrast, the assemblages of the Early Neolithic C show changes in lithic technology

Motion Estimation and Compensation in Automotive MIMO SAR

With the advent of self-driving vehicles, autonomous driving systems will have to rely on a vast number of heterogeneous sensors to perform dynamic perception of the surrounding environment. Synthetic Aperture Radar (SAR) systems increase the resolution of conventional mass-market radars by exploiting the vehicle's ego-motion, requiring a very accurate knowledge of the trajectory, usually not compatible with automotive-grade navigation systems. In this regard, this paper deals with the analysis, estimation and compensation of trajectory estimation errors in automotive SAR systems, proposing a complete residual motion estimation and compensation workflow. We start by defining the geometry of the acquisition and the basic processing steps of Multiple-Input Multiple-Output (MIMO) SAR systems. Then, we analytically derive the effects of typical motion errors in automotive SAR imaging. Based on the derived models, the procedure is detailed, outlining the guidelines for its practical implementation. We show the effectiveness of the proposed technique by means of experimental data gathered by a 77 GHz radar mounted in a forward looking configuration.Comment: 14 page

Lens based switched beam antenna for a 5G smart repeater

A 16 switched beam lens based antenna with a coverage area of ±30° in the horizontal plane and from 0 to -20° in the vertical plane has been built and tested. The intended use of the antenna is as part of a smart repeater servicing the coverage area of a 5G wireless communication system operating in the n258 band of the 5G Frequency Range 2, from 24.25 to 27.5 GHz. The antenna has been built using state-of-the-art materials and components in order to assess the performance of this antenna concept. The overall antenna losses including the feeding network are of the order of 8 dB and the realized gain in the 80% of the coverage area is above 11 dB.This work was funded in part by AEI: PID2019-107885GB-C31/AEI/10.13039/501100011033 and HUAWEI TECHNOLOGIES Italia S.r.lPeer ReviewedPostprint (author's final draft

Multi-Vehicular Beam Space Learning for Channel Estimation in 6G V2X Systems

Channel knowledge is a fundamental requirement for accurate analog-digital beamforming in hybrid MIMO systems. Conventional channel estimation techniques, e.g., unconstrained maximum likelihood, cannot be used to directly estimate the full MIMO channel in hybrid systems, as the analog beamforming limits the channel observation to the digital side only. We propose a two-stage channel estimation procedure for 6G Vehicle-to-Everything (V2X) systems, leveraging multiple recurrent vehicle passages over the same location, properly clustered in space, in both the analog beam training (stage 1) and the algebraic digital channel estimation (stage 2). We show that the proposed method practically matches the perfect channel knowledge performance on a wide range of Signal-to-Noise Ratio (SNR) values, discussing its behavior with respect to the cluster size

5_figures+mapfiles

R-Markdown file. This contains the in house scripts used to process raw data files and run all downstream analyses reported in our paper. The script includes code to smooth recombination maps, generate motif density files, test correlations and and fit linear models to examine the relationship between motif density and recombination rate, at different smoothing scales, in Dmel and Dsim. Details can be found in our paper