Theory of Communication
FEKT-NTOCAcad. year: 2019/2020
The course deals with principals, methods and characteristics of communication systems. It focuses on modern digital systems and modulation methods in particular. However, student of the course can also intensify his/her knowledge of analog modulations, their parameters and implementations. At the same time, student learns lot of technical terms and expands his/her vocabulary for the field of communication technology.
Learning outcomes of the course unit
Student, who passed the course, is able:
- to distinguish basic types of binary signals, to compute and draw their spectra and describe principles and characteristics of the most widely used line codes,
- to list individual blocks of the digital communication system and explain their functions,
- to describe additive white Gaussian noise (AWGN) channel model, to define bit error rate, to compute probability of error reception in case of both baseband and passband binary signal transmission affected by AWGN,
- to describe principles, to define parameters and to list characteristics of basic and modern modulation methods,
- to explain the cause of intersymbol interferences (ISI) and Nyquist strategy of zero ISI in sampling moments, to draw and describe impulse responses of both raised cosine and Gaussian shaping filters,
- to describe the principle of channel equalization, to explain operations of adaptive equalizer and decision feedback equalizer,
- to explain the principle and importance of synchronization in the communication system, to explain the purpose of scrambling, to design the block diagram of a simple self-synchronizing scrambler,
- to describe principles of the automatic repeat request (ARQ) and the forward error correction (FEC), to explain the principle of interleaving, to describe methods of block and convolutional interleaving,
- to explain the difference between natural and uniform methods of sampling, the cause of aperture distortion and methods of its suppression,
- to describe principles of the pulse width modulation (PWM), the pulse position modulation (PPM) and the pulse density modulation (PDM),
- to explain the difference between uniform and non-uniform methods of quantization, to compute the power of the quantization noise, to draw the graphs of compressor and expander transfer functions,
- to describe principles and to list basic characteristics of pulse coded modulations (PCM, DPCM, DM, ADM, SDM),
- to explain principles of basic methods of signal multiplexing and multiple access,
- to describe and design the orthogonal frequency division multiplex (OFDM), to define its basic parameters and to list its typical characteristics and examples of application,
- to describe basic types of intensity modulations of light used in optoelectronics,
- to define and compute basic quantities used in the information theory (self-information, entropy, redundancy, mutual information, channel capacity), to explain the principle of the trellis coded modulation (TCM).
Student, who enrolls for the course, should know basic definitions and characteristics of signals and systems with both continuous and discrete time, including their mathematical description and representation in the frequency domain, and also know basic types of probability density and distribution functions and have knowledge of the signal sampling and filtration. It is also assumed that student can compute the derivative and integral of a function, modify equations with logarithms, complex numbers and trigonometric functions and solve linear equations. In general, the bachelor level knowledge from the area of mathematics and general English language competence are required.
Recommended optional programme components
Recommended or required reading
PROAKIS J. G. Digital Communications. 4th ed., New York (USA) : McGraw-Hill, 2001. 1002 p. ISBN 0-07-232111-3 (EN)
HAYKIN S., MOHER M. Introduction to Analog & Digital Communications. 2nd ed., New Jersey (USA) : John Wiley & Sons, 2007. 515 p. ISBN 0-471-43222-9 (EN)
SKLAR B. Digital Communications. 2nd ed. Upper Saddle River (USA) : Prentice Hall, 2003. 1080 p. ISBN 0-13-084788-7 (EN)
XIONG F. Digital Modulation Techniques. 1st ed. Norwood (USA) : Artech House, 2000. 653 p. ISBN 0-89006-970-0 (EN)
HSU H. P. Schaum's Outline of Theory and Problems of Analog and Digital Communications. 2nd ed., New York (USA) : McGraw-Hill, 2003. 331 p. ISBN 0-07-140228-4 (EN)
GITLIN R. D., HAYES J. F., WEINSTEIN S. B. Data Communications Principles. New York (USA) : Plenum Press, 1992. 733 p. ISBN 0-306-43777-5 (EN)
Planned learning activities and teaching methods
During the lectures, the theory is explained with the aid of MATLAB-SIMULINK models and solution of practical examples. The Moodle e-learning software is used for the final testing of students’ knowledge.
Assesment methods and criteria linked to learning outcomes
The final grade depends on the number of correctly answered questions of the final computer quiz prepared using the Moodle e-learning software. Student can obtain from 0 to 100 points in total. The 50 points is the minimum which corresponds with just half of correctly answered questions.
Language of instruction
1) Signals in communication systems. Basic waveform representations of binary digits. Modulation rate and bit rate.
2) Line codes. Required channel bandwidth. General digital communication system.
3) Noise in communication systems. AWGN channel. Probability of error. Matched filter. Correlation receiver.
4) Amplitude modulation, frequency modulation and phase modulation.
5) Amplitude shift keying, frequency shift keying and phase shift keying.
6) Modern digital modulations with harmonic carrier (QPSK, 8PSK, OK-QPSK, MSK, FFSK, GMSK, pi/4-DQPSK, MQAM, CAP).
7) Effect of the noise in passband. Modulations in optoelectronics.
8) Digital representation of analog signal. Quantization. Pulse modulations.
9) Reduction of intersymbol interference (ISI). Synchronization. Scrambling.
10) Methods of error control. Interleaving.
11) Equalization of channel transfer function.
12) Multiplexing and multiple access. Spread spectrum systems. Orthogonal frequency division multiplex (OFDM).
13) Introduction to the information theory. Trellis coded modulation (TCM).
Give basic information about signals, methods, principles and parameters of communication systems, especially the digital systems, and also about negative effects on the bit error rate speed of transmission. To acquaint students with English terminology, lexicon, and specificity of English technical texts in the area of modern communication technologies using the set of lectures focused on the explanation of their principles.
Specification of controlled education, way of implementation and compensation for absences
Only the passing of the final computer quiz is compulsory (see the criteria linked to learning outcomes).