35167 - Communication Systems: Theory and Measurement M

Learning outcomes

The main concepts for the design criteria of analog and digital communication systems are introduced. The fundamentals concerning transmission on band-pass channel in a realistic environment and basic ideas on multiple access techniques are provided. Finally some application examples such as digital radio links, satellite systems, short range wireless communication and mobile networks are investigated. Seminars are included in the lectures given by experts from Telecommunication industry.

Course contents

(Module 2 – Prof. Dardari)

· Introduction to wireless systems.

1. Introduction to the course: Evolution of communication systems.
2. Recalls: Real and complex Gaussian random variables. Rayleigh, exponential and chi-square statistics. Real and complex Gaussian vectors. Basic matrix algebra, eigenvalue and single-value decomposition (SVD).
3. The wireless channel: Main characteristics. Frequency and time selectivity of the wireless channel. Coherence time and bandwidth. Multipath propagation: the tapped delay line model. The Clarke model: Rayleigh fading, Jakes spectrum.
4. Geometric representation of signals. Low-pass discrete-time equivalent model of band-pass signals. Exercises.

· Detection theory fundamentals.

1. Introduction to detection theory. Hypothesis test: the MAP criterium for the minimum probability of error. The maximum likelihood (ML) test. Examples.
2. Optimal detection of 2 waveforms in AWGN: correlator and matched filter receivers. Examples.

· Optimal transmission in bandlimited non-selective channels.

1. Linear modulations: Constellation and spectral characteristics. The conventional signal-to-noise ratio Eb/No. Optimal transmission in AWGN: MAP and ML criteria. Particular case: symbol-by-symbol detection. General expression of the (un-coded) probability of error: union bound.
2. Examples of constellations and associated (un-coded) probability of error: L-ASK, L-PSK, M-QAM. Definition of spectral efficiency and considerations on the trade-off between spectral and energy efficiency.

· Transmission in the presence of channel selectivity.

1. Transmission in the presence of flat fading. Link budget criteria in the presence of fast and slow fading: outage probability and average probability of error.
2. Optimal transmission in the presence of frequency selectivity: the MLSE receiver. Suboptimal schemes for adaptive equalization: Linear equalizers.
3. OFDM technique and its applications.
4. Example: The digital video broadcasting standard (DVB)

· Multi-antenna systems (MIMO).

1. Definitions. Effect of the propagation environment (LOS, rich NLOS, keyhole).
2. SIMO system: maximal ratio combining (MRC).
3. MISO system with and without channel state information at the transmitter (CSIT): optimal scheme with CSIT (SVD-MIMO), beamforming and Alamouti scheme (no CSIT).
4. Hints on V-BLAST, Zero-forcing, MMSE, and SIC receivers. Multi-user MIMO and massive MIMO (hints).

(Module 1 – Prof. Pasolini)

· Laboratory activity

1. Introduction to Matlab simulation software
2. Design and implementation of functional blocks for the generation of modulated signals
3. Design and implementation of functional blocks for the decoding of modulated signals
4. Use of software defined radio devices

Readings/Bibliography

The acquisition of dedicated books is not required. Lecture slides are available on Moodle.

Bibliography for further deepening:

D. Tse and P. Viswanath, "Fundamentals of Wireless Communications", Cambridge University Press, 2005.

A. Goldsmith “Wireless Communications”, Cambridge University Press, 2005

J.Proakis, “Digital Communications”, Mc Graw Hill.

J.D. Parsons, “The Mobile Radio Propagation Channel”, Second Edition, John Wiley & Sons.

Oreste Andrisano, Davide Dardari "Appunti di Sistemi di Telecomunicazione: elementi di progetto di sistemi radiomobili”, Esculapio, Bologna, 2001.

Teaching methods

The course is composed of 2 modules for a total of 9 CFUs, of which 6 CFUs as frontal lectures (Module 2) and 3 CFUs as experimental activity (Module 1). The experimental activity takes place in the laboratory with the objective to let the student familiar with the design and simulation tools (Matlab) used to generate and measure modulated signals. The activity is organized in groups of 2-3 students each.

In consideration of the type of activity and teaching methods adopted, the attendance of this training activity requires the prior participation of all students in modules 1 and 2 of training on safety, [https: //elearning-sicurezza.unibo .it /] in e-learning mode.

Assessment methods

An oral exam, comprehensive of the two modules, will assess skills acquired during the course and evaluate the achievement of the educational objectives:

• Knowledge of the principles of digital communication systems
• Knowledge of the main design techniques when operating in the presence of anomalous propagation conditions
• Skills in analyzing and designing a wireless communication link
• Knowledge of laboratory tools for the generation and analysis of modulated signals.

The final exam assessment will be based on three specific questions related to the main objectives of the course. One out of the three questions may regard solving design and analysis exercises related to communication systems.

Teaching tools

Educational material: Lecture notes presented in class will be available to students in electronic format through the School Intranet (Moodle).

Experimental activity using Matlab and laboratory instrumentation (function generator, oscilloscope, spectrum analyzer, software defined radios).

Office hours

See the website of Davide Dardari

See the website of Gianni Pasolini