82069 - Electromagnetic Propagation for Wireless Systems M

Course Unit Page

Academic Year 2018/2019

Learning outcomes

Mastery in engineering electromagnetic topics related to wave propagation. Knowledge of the main properties of radio propagation in real environment, expertise on path-loss models, multipath propagation modeling and radio channel wideband characterization. General comprehension of MIMO systems, diversity and spatial multiplexing techniques. Awareness of the main coverage and planning strategies for cellular radio, broadcasting and wireless systems. Assessment of wireless systems efficiency.

Course contents

Part I – Fundamentals of Electromagnetic Theory.

Maxwell’s Equations

Coordinate systems, Vector operators. Maxwell’s Equations in integral and differential form. Constitutive relations. Boundary Conditions. Sinusoidal fields and complex notation. Maxwell’s Equations for time-harmonic fields. Vector Potential. Field generated by a point, surface and volume source. Spherical Waves.

Basic properties of the electromagnetic field

Polarization of the electromagnetic field. Power balance and Poynting Theorem. Perfect conductors, surface currents, Equivalence theorems and Image principle.

Plane waves

Plane waves in lossless and lossy media. Energy density and wave impedance. Reflection and transmission of plane waves

Field propagation in homogeneous media.

Expression of a field as an integral of plane waves. Concept of spatial frequency. Relationship between far field and source field. Near field and far field. Diffraction phenomena. Radiation vector and far field. Spherical waves. Basic radiation quantities

Elements of guided wave propagation

Longitudinal-transversal decomposition of Maxwell’s Equations. Concept of mode. Cutoff frequency. Simple examples: Dielectric slab waveguide and parallel plane metal waveguide

Geometrical Theory of Propagation

From Maxwell’s to Geompetrical Optics equations. Ray based description of wireless propagation. Tracking of the reays trajectories and computation of the electromagnetic field along the rays.

 

Part II – Propagation in Wireless Systems

Wireless propagation in real environment

From ideal (Friis formula) to real propagation. Fading effects: radio link obstruction and multipath propagation. Dependence of a wireless digital system performance on the propagation conditions.

Introduction to the environmental effects. Example: impact of the terrain on the radio link, atmospheric effects on wireless links. Tropospheric and ionospheric propagation.

Radio channel modelling: narrowband and wideband characterization

Narrowband analyses of field distribution: path loss, shadowing and fast fading. Okumura-Hata formula and shadowing models. Radio Coverage of a single cell.

Multipath effects and input-output functions of the (mobile) radio channel

Radio coverage: narrowband field prediction models.

Wideband characterization of propagation (Delay Spread, Angle Spread, etc.) and wideband propagation models (rays models).

Multi-antenna systems

MIMO solutions and techniques for fading mitigation / channel capacity increase: spatial diversity, beamforming and spatial multiplexing

Introduction to cellular wireless systems

Cellular tessellation and radio resource management, spatial reuse. Introduction to the multiple access techniques: TDMA, FDMA, CDMA and SDMA. Multi-user MIMO: Zero Forcing and Geometric Beamforming.

Readings/Bibliography

Course slides and notes.

D.A. McNamara. C.W.I Pistorius, J.A.G. Malherbe, Introduction to the uniform geometrical theory of diffraction, Artech House, 1990.

H. L. Bertoni, Radio Propagation for Modern Wireless Systems, Prentice Hall, 2000

N. Costa, S. Haykin, Multiple-Input Multiple Output Channel Models – Theory and Practice, Wiley& Sons, 2010

Teaching methods

The course includes lectures given by the professor, and exercises carried out by the professor as well as assigned to the students.

Assessment methods

The exam is organized into a written and a following oral discussion.

The written test consists of further two parts:

(i) a multiple-choice test on the general theory of electromagnetism. It lasts about 30 minutes, and the use of personal notes or other supporting material is strictly forbidden;

(ii) a full exercise on topics related to electromagnetic propagation in wireless links and networks. The use of books, notes and pocket calculator is here allowed (access to the web and to any particular software tool is on the contrary forbidden).

The outcome of the written test should be positive (i.e. at least 6 out of 10 for the multiple-choice test, and 18 out of 30 for the full exercise) in order to proceed with the oral discussion.

The oral discussion (15 min approx.) aims at assessing the comprehension of the main concepts explained during the course.

The final mark is a synthetic, weighted evaluation of the outcomes of the written and oral parts.

Taking the written and oral tests within the same exam session is strongly recommended; in any case the validity of the written test score is limited to the current academic year.

Teaching tools

Blackboard, PC, projector.

Office hours

See the website of Franco Fuschini

See the website of Giovanni Tartarini