IA/0128 - PERVASIVE WIRELESS COMMUNICATIONS
Academic Year 2019/2020
Free text for the University
GIUSEPPE MAZZARELLA (Tit.)
GIOVANNI ANDREA CASULA
- Teaching style
- Lingua Insegnamento
|[70/91] INTERNET ENGINEERING||[91/00 - Ord. 2018] INGEGNERIA DELLE TECNOLOGIE PER INTERNET||10||100|
The general goals of the course is first to describe in detail the propagation models for an electromagnetic signal in an rich-scattering environment, such as the urban and indoor environment, and then to present methods for the analysis and the design of wireless devices which must work close to the human body or, more generally, in an indoor environment.
In particular, in the first module of the course, the mechanisms of propagation of an electromagnetic signal in environments with high scattering, like the urban environment, will be describe in detail. The methods of evaluation of attenuation will be examined both for the indoor propagation, and for the passage of the signal from outdoor to indoor environments. The student, at the end of the module, will acquire knowledge and understanding of the electromagnetic field behavior in the presence of multipath and slow fading, and will be able to apply this knowledge to design antennas and wireless systems working in such conditions, also thanks to the exercises presented during the course itself.
Then, techniques of analysis and design of wireless devices that must work close to the human body, or in any case in an indoor environment, will be presented in the second module. In more detail, at the end of the module the student will acquire the necessary knowledge to design antennas and wireless devices that work in such conditions. Obviously, being a course for a Second Level Degree, the focus has been on a single application, namely the Radiofrequency Identification (RFID), examining all the technical aspects and linking them to the constraints and opportunities that these applications have. And using them as a reference to discuss other applications, such as Power Wireless Transfer or On-Body Communications. Also for the placement of the course, the student will also acquire knowledge on the state of the art industrial for these services, and the limitations, including legal, to their use.
The chosen way to verify the preparation will develop the communication skills as required to an engineer.
A good knowledge of Applied Electromagnetics topics, in particular those related to antennas, is required. A knowledge of the fundamentals of "Design of Wireless Systems" is strongly recommended for a more effective understanding of the course topics.
The course is divided into two modules. The first deals with indoor communications and the second will be focused on a in-depth discussion of RFId systems and Weareble Antennas.
The first module of the course describes the attenuation mechanisms in complex environments, particularly in environments affected by multipath and slow fading. The methods for estimating the attenuation will be examined both for indoor propagation, and in the passage of the electromagnetic signal from outdoor to indoor environments. Moreover, also the attenuation through walls will be calculated, in order to have a reasonable estimate also of the absorption due to the dissipative obstacles existing in the propagation environment. Part of the course is dedicated to MIMO systems, and to diversity (spatial, in time, in frequency, in polarization), used in wireless communications to compensate for the fading affecting the signal due to the multipath. In addition, the level of interfering signals will be estimated, and the identification of the main sources that can cause interference depending on the wireless application of interest, since, because of these sources, due to other applications that work at the same frequency, or frequencies close to that of interest, there is a worsening of the signal to noise ratio.
The second module will be focused on the analysis and design of microwave RFId systems, in particular in the UHF band, covering all aspects of the system, from the radio ones, to those related to signals and modulation up to the circuital aspects. The choice to focus on a system, obviously very relevant for applications, is linked not only to professional aspects, but also to highlight how the technological and regulatory constraints on the one hand and the freedom of performance on the other orient, in cnnection with the economic requests, the design choices. Some aspects of the system will be discussed in a broader form, not limited to the RFId system (for example, the mixers) or will be generalized to further applications, such as Wireless Power Transfer. Since RFID tags often work in the presence of lossy materials, or close to the human body, these aspects naturally lead to the second part of the course, related to wearable antennas. For this topic, after an examination of the problems that the human body, and similar materials from the electromagnetic point of view, put on radio communications, some examples of use will be shown. Among these, the UWB communications, which are a state-of-the-art system for on-body communications, will be described in greater detail.
There will be a fairly balanced division between lectures and practical activities. In particular, the lectures will be both training and practical, with numerical examples of application of the relationships described in the theoretical part, and with extensive description and considerations on the consequent impact on the implementation of the system in question. Practical activities will be mainly based on the use of commercial electromagnetic simulators, through which will be analyzed and designed appropriate wireless systems that highlight the problems and concepts expressed during the theoretical lessons.
Verification of learning
This course is strongly oriented to the design of component for wireless communications. Therefore, to get the highest grade requires to be able to apply all the competencies acquired during the lectures.
For this reason, during the course, students will be asked to develop topics covered during the exercises, with the drafting of a report. In addition, to pass the exam, the student is expected both to expose to the class, at a significantly deeper level, a topic, chosen among those presented in the first module, covered during the lectures, with a presentation of 15-20 minutes (which could be replaced by a standard oral examination on the topics of the first module), and a project activity on the topics of the second module to be carried out (outside the lesson time) in small groups, which will require not only the project but also the analysis of the problem, all documented by the preparation of a final report. The presented reports are then scheduled for discussion during the final exam.
The final grade will take into account the knowledge, skills and competences acquired. In particular, a reasonable level of knowledge, combined with even minimal skill, is a necessary condition for a positive result.
K. Fujimoto: Mobile Antenna Systems Handbook - Ed. Artech House;
R. Vaughan, I. Bach Andersen: Channels Propagation and Antennas for Mobile Communications - Ed. IEE;
F De Flaviis et al.:Multiantenna Systems for MIMO Communications - Ed. Morgan & Claypol;
D.M. Dobkin: The RF in RFId - Ed. Newnes;
N. Shinohara - Wireless Power Transfer via Radiowaves - Ed. Wiley
P.S. Hall, Y. Hao: Antennas and Propagation for Body-Centric Wireless Communications - Ed. Artech House;
T. Zwick et al (Eds): Ultra-wideband RF System Engineering - Ed. Cambridge Univ. Press;
Review articles on scientific journal;
Review articles will be made available inside the University internet domain.