# Mobile Systems

## Course description

The basic model of digital transmission. Basic concepts of information theory (probability, information, random variables, information sources, entropy, redundancy). Lossless source coding (elimination of redundancy). Loosely source coding (elimination of irrelevance). Information channel. Binary symmetric channel. Gaussian channel. Mutual entropy and information channel capacity. Channel coding. Error detecting and error correcting codes. Examples of channel coding (uncoded transmission, block codes, convolution codes, trellis diagram). Maximum likelihood decoding. Viterbi algorithm.

Baseband transmission.  Linear distortion and inter-symbol interference (ISI). The Nyquist criterion for ISI free transmission. Adaptive equalization and ISI cancellation. The spectrum of baseband signals and spectral efficiency.

Transmission of signals in the higher frequency bands. Digital modulation (amplitude, phase, and frequency modulation). Examples of digital modulation (PAM, FSK, PSK, DPSK, CPM, MSK, GMSK, QAM). Spread spectrum. Multiple access to a common transmission medium.

## Objectives and competences

The course provides basic knowledge in the field of the transmission of information signals, which is the basis of all modern communication systems. The purpose of the course is to acquaint the future engineers with the theoretical basics of efficient and reliable transmission of digital signals through the non-ideal communication channel. The theory provides a useful basis for the subjects in the second degree of the study. In addition to the theoretical foundations, an overview of existing solutions is given, which gives the students a basic understanding of the existing communication systems faced in their everyday life.

## Learning and teaching methods

Lectures on which the student is acquainted with the theoretical basics and lab work, where he learns how to solve some practical problems in the spirit of teamwork.

## Intended learning outcomes

After successful completion of the course, students should be able to:

•  analyze the transmission path,
•  evaluate the suitability of modulation methods for a given transmission path,
•  evaluate the suitability of channel coding for the given transmission path,
• assess the impact of noise on communication quality,
• design a simple digital transmission system.

## Reference nosilca

1. TOMAŽIČ, Sašo. Spectral efficiency. Encyclopedia of wireless and mobile communications. Boca Raton; New York: Taylor & Francis Group: Auerbach Publications, cop. 2008, vol. 2, str. 1095-1099.
2. TOMAŽIČ, Sašo. Comments on spectral efficiency of VMSK. IEEE transactions on broadcasting, 2002, vol. 48, no. 1, str. 61-6
3. TOMAŽIČ, Sašo. Risidual noise reduction in sign algorithm. IEEE signal processing letters, 2000, vol. 7, no. 8, str. 233-234.
4. TOMAŽIČ, Sašo, ŠTULAR, Mitja. Razširjeni spekter v mobilnih komunikacijah: (1) Sistemi z raširjenim spektrom. Elektrotehniški vestnik, 1998, let. 65, št. 5, str. 303-310.
5. BERTOK, Jurij, TOMAŽIČ, Sašo. Sekvenčno dekodiranje konvolucijskih kod. Elektrotehniški vestnik, 1991, let. 58, št. 5, str. 291-301.

## Study materials

1. Tomažič, S., Osnove telekomunikacij I, Založba FE in FRI, Ljubljana 2002
2. Tomažič, S., Digitalne komunikacije, Prenos digitalnih signalov, Založba FE, Ljubljana 2017.
3. Haykin, S., Communication systems, 4th edition, John Wiley & Sons, New York, 2001, 816 str. Glover, I., Grant, P., Digital communications, Prentice Hall, London 1998.

## Bodi na tekočem

Univerza v Ljubljani, Fakulteta za elektrotehniko, Tržaška cesta 25, 1000 Ljubljana