The goals of the course are (i) to teach students the peculiar characteristics of wireless communication (in the wider area of digital communications), (ii) to make students able to understand and apply the techniques for addressing the challenges in the design of a wireless communication system and (iii) to make student understand the reasons behind the fundamental solutions adopted in the current advanced wireless technologies. In fact, with respect to other physical media, wireless communication is supposed to face three fundamental issues: very limited available frequency bandwidth, fading and signal dispersion phenomena in the channel and interference generated by coexisting signals. The course provides the instruments for modeling these aspects and understanding their impact on performance, and the technological solutions for addressing or limiting them. Each topic related to the use of specific models is treated both theoretically and practically.

1-  Knowledge and understanding

Students will learn how to:

- define mathematical and statistical models for the analysis of wireless channels;

- analyze performance of digital modulation scheme in presence of random fading;

- analyze performance and limits of the fundamental solutions for wireless communication: diversity techniques, multiple antennas, adaptive systems;

- identify trade-offs between performance and design requirements;

- identify the role of system components and their relations.

2-  Applying knowledge and understanding

Students will be able to:

- dimension the fundamental parameters (bandwidth, power, modulation, ...) of a radio transceiver given the performance requirements;

- evaluate the performance of a wireless link in different propagation environments;

- apply the mathematical and statistical models learned.

3-  Making judgements

Students will be able to:

- understand the fundamental tradeoffs in the design of wireless systems;

- identify how the wireless channel characteristics impact the design of the system and its performance

- recognize the design potential of advanced wireless technologies (e.g. multiple antennas, cooperation, smart resource allocation).

4-  Communication

- Describe, exploiting also appropriate mathematical formulations, a wireless technology or a wireless communication topic at different levels of detail.

- In the case of a project, present an advanced topic with a brief presentation and talk (not mandatory).

Wireless Communications


1. Introduction

The radio spectrum.

Classification and characteristics of wireless systems.

2. Wireless channel models

Channel attenuation. Pathloss.

Random components: shadowing and multipath propagation.

Doppler effect. Impulse response.

Statistical and empirical models.

3. Digital modulation for wireless systems

Single carrier modulations: amplitude and phase modulation, continuous phase modulation (CPM).

Multicarrier modulations, OFDM.

Spectral density of the modulated signals.

Performance evaluation in presence of fading.

4. Techniques for efficient transmission on wireless channels

Diversity techniques.

Adaptive modulation.

Coding (ARQ, interleaving).

Multiple antennas and spatio-temporal coding. MIMO systems. 

5. Wireless Multiple access

Review of time and frequency division methods.

Code division access (CDMA).

OFDMA, SC-FDMA.

Advanced resource allocation techniques.

6. Wireless networks

Fundamentals on cellular systems.

Frequency reuse, interference computation, techniques for limiting interference. 

7. Wireless systems

Third generation cellular systems (UMTS, HSPA), 4G (LTE, LTE-A) and evolution towards 5G.

Evolution in wireless local and personal area networks (IEEE 802.11, IEEE 802.15).

Students are required to know the principles of communications systems and digital communications. They are also expected to have a basic knowledge of probability theory.

The assessment will be based on a written exam at the end of the course, possibly completed by an oral one.

The written exam is composed by 3 problems and each problem includes 3-4 questions, partly to be solved (exercises) and partly to be answered according to the knowledge and understanding of the course topics. After the written exam, the following results can be proposed: not sufficient (the exam has to be repeated), oral (an oral exam is mandatory for having a final score), a score between 18 and 30 cum laude (the oral exam is not mandatory but it can be requested by the student).

The oral starts with the discussion of the written exam and then it can be extended to other questions.

The written exam can be replaced by a project, typically in Matlab, on one of the recent wireless technologies; in this case the oral is mandatory, it starts with the presentation of the project and then it is focused on the other topics of the course.