Franco Fuschini

Ray-Tracing-Based mm-Wave Beamforming Assessment

The use of large-size antenna arrays to implement pencil-beam forming techniques is becoming a key asset to cope with the very high throughput density requirements and high path-loss of future millimeter-wave (mm-wave) gigabit-wireless applications. Suboptimal beamforming (BF) strategies based on search over discrete set of beams (steering vectors) are proposed and implemented in present standards and applications. The potential of fully adaptive advanced BF strategies that will become possible in the future, thanks to the availability of accurate localization and powerful distributed computing, is evaluated in this paper through system simulation. After validation and calibration against mm-wave directional indoor channel measurements, a 3-D ray tracing model is used as a propagation-prediction engine to evaluate performance in a number of simple, reference cases. Ray tracing itself, however, is proposed and evaluated as a real-time prediction tool to assist future BF techniques.

Directional characterization of the 60 GHz indoor-office channel

Directional, dual-link, quad-polarized 60GHz channel measurements have been carried out in a small-office environment. Purpose of the measurements is to study the directional properties of the channel in view of future multi-gigabit system adopting beam-forming or macro-diversity solutions. The impact of polarization on the characteristics of the channel is also addressed in the study.

A Mixed Rays—Modes Approach to the Propagation in Real Road and Railway Tunnels

These days, security and efficiency of transportation networks are usually supported by wireless communication systems. In all cases, the radio-link reliability strongly depends on propagation properties and, therefore, effective prediction tools and models are requested in the design and planning phases of the radio system. In this paper, a mixed rays-modes approach to the propagation modeling in real tunnels is presented. The propagating field is computed as the superimposition of many characteristic modes, whose amplitudes are properly estimated thanks to a limited and, therefore, fast ray-tracing procedure; the geometrical optics rules are also used to model the main effects of the possible tunnel curvature. Moreover, an equivalent wall roughness is introduced in order to approximately account for the actual tunnel transversal shape and for the presence of inner elements and objects. The model is compared with some other different existing models and with measurements carried out inside an underground line in a neighborhood of Naples. The achieved performance is in line with the published scientific data.

Interleaved-MIMO DAS for Indoor Radio Coverage: Concept and Performance Assessment

Distributed antenna systems (DAS) represent a suitable method for extending multiple-operator radio coverage into indoor premises, tunnels, etc. With the advent of 4G (and beyond) mobile communications systems and of multiple input-multiple output (MIMO) transmission techniques, a common problem for wireless operators is how to upgrade existing DAS systems to the MIMO technology in a cost-effective way. In this paper novel indoor solutions based on the combination of DAS and MIMO transmission techniques (Interleaved-MIMO DAS solutions) are proposed, and their performance is investigated in realistic cases with the aid of measurements, ray tracing simulations, and LTE link-level simulations.

A Meaningful Indoor Path-Loss Formula

A simple indoor path-loss formula is proposed that is both simple and physically sound, as it accounts for major propagation processes taking place in indoor environment: namely wave-divergence and obstruction. The formula is shown to well reproduce the path-loss versus distance trend in different indoor environments. Moreover, its parameters are closely related to major environment characteristics, and therefore the formula can be parameterized in simple cases even without resorting to measurement-based tuning.

Consolidating the Electromagnetic Education of Graduate Students Through an Integrated Course

In the context of an international, English-spoken, post-graduate Telecommunications Engineering program, the Faculty of Engineering of the University of Bologna, Italy, offers a course “Electromagnetic Technologies for Link Design,” conceived for both telecommunications students and Masters students from various engineering fields, all with very different Bachelor degree backgrounds. The course addresses the increasing demand from industry for engineers who are comprehensively educated, rather than extremely specialized. The course lecturers have expertise in various areas of applied electromagnetics and use a deductive approach to show diverse applications, all grounded in the same basic electromagnetic concepts.

A statistical approach to the evaluation of the coverage area of UHF RFID systems

In the field of RFID technology, the shift from the traditional HF band to the UHF one exposes the system to the typical impairments due to radio-wave propagation. These effects are related to the environmental properties and can have a strong impact on the system performance, which is often reduced and worsened with respect to the reference, free space case. Therefore, reliable models for the prediction of UHF RFID system performance in real environment are requested. This work proposes a statistical approach to the evaluation of the coverage area and probability in UHF RFID systems operating in real scenarios; the model is described in its theoretical fundamentals and is tested over some measurements carried out in a couple of realistic cases. The comparison shows a quite satisfactory agreement.

Interleaved-MIMO DAS for Indoor Radio Coverage: Guidelines for Planning

The combination of distributed antenna systems (DAS) and multiple input multiple output (MIMO) schemes opens the way to a variety of coverage solutions for indoor environment. In this paper interleaved-MIMO (i-MIMO) DAS indoor coverage extension strategies are studied. Their performance in high-order MIMO cases is investigated in realistic conditions through LTE-A link-level simulations, based on statistical data extracted from radio channel measurements; the impact of the deployment strategy on performance is then evaluated and useful planning guidelines are derived to determine the optimum deployment for a given propagation environment.

Experimental Investigation of the Effects of Snowdrifts and Ice Deposit on Linear Wire Antennas at 2.4 GHz

An experimental evaluation of the possible effects produced on wireless links operating at 2.4 GHz by snow and ice accumulation over the antennas is presented. The measurement outcomes show that an additional loss increasing with the dimension of the snow/ice coating must be expected. If the antenna is only partly covered, snow and ice seem to produce similar extra loss, whereas ice appears a much more serious threat than snow if the antenna is completely submerged. The achieved experimental data are in a rather satisfactory agreement with the analytical prediction carried out with an existing theoretical model.

Study of indoor radio coverage solutions based on Interleaved-MIMO DAS

In the present work, the performance of indoor deployment solutions based on the combination of Distributed Antenna Systems (DAS) and MIMO transmission techniques (Interleaved-MIMO DAS solutions) is investigated for high-order MIMO schemes with the aid of LTE link level simulations. Planning guidelines for linear and 2D coverage solutions based on Interleaved-MIMO DAS are then derived.