Theory of Communication
FEKT-LTSDAcad. 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. The theoretical information obtained at tutorials are subsequently verified by laboratory measurements with specially designed instruments and also by computer simulations with models built in the MATLAB-SIMULINK environment. During the tutorials students learn how to compute basic parameters needed for communication system design using practical examples.
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, solve linear equations and use the MATLAB software. In general, the bachelor level knowledge from the area of mathematics and physics are required.
Recommended optional programme components
Recommended or required reading
ČÍŽ R. Principy modulací a přenosu sdělovacích signálů pro integrovanou výuku VUT a VŠB-TUO. 1. vyd. Brno : Vysoké učení technické v Brně, 2014. 140 s. ISBN 978-80-214-5117-9. (CS)
DOBEŠ J., ŽALUD V. Moderní radiotechnika. 1. vyd., Praha : BEN, 2006. 768 s. ISBN 80-7300-132-2 (CS)
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)
PROAKIS J. G. Digital Communications. 4th ed., New York (USA) : McGraw-Hill, 2001. 1002 p. ISBN 0-07-232111-3 (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)
Planned learning activities and teaching methods
Teaching methods comprehend lectures, computer exercise and laboratory measurement. The MATLAB software is used for computer exercises. Laboratory measurement proceed with the aid of specially prepared electronic instruments, Siglent SDG2042X generators and Keysight DSOX2012A scopes. Student have to process six assignments during the course.
Assesment methods and criteria linked to learning outcomes
The final grade depends on total sum of points obtained during the laboratory measurements, computer simulations, professional trainings and written exam of the course. Student can get:
- up to 25 points for five assignments,
- up to 5 points for laboratory measurements,during them student obtain points for correctly measured results and conclusions stated in the given protocol,
- up to 5 points for computer exercises, during them student obtain points for correctly processed tasks,
- up to 65 points for the compulsory exam, which has a written form and only students who passed the laboratory measurements and computer exercises and who submitted all processed assignments are able to take a make-up it. If the examinator has a problem with the evaluation of the written exam, he/she can put supplement oral questions to the student.
Language of instruction
1) Signals in communication systems (continuous, discrete). Basic waveform representation of binary digits. Line codes. Noise in communication systems. Receiving of disturbed signal.
2) Amplitude and frequency modulations and keyings. Phase modulation and keying. Problems of BPSK data transfer.
3) Modern discrete modulations with harmonic carrier (QPSK, 8PSK, OK-QPSK, MSK, FFSK, GMSK, pi/4-DQPSK, MQAM). Reducing of intersymbol interference (ISI). Equalizers. Synchronization. Scrambling.
4) Digital representation of analog signal. Quantization. Pulse modulations (PAM, PDM, PPM, PWM, PCM, DPCM, DM, SDM). Multiplexing and multiple access. OFDM.
5) Modulations in optoelectronics. Effect of the noise in passband. Introduction to the information theory. Trellis coding.
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.
Specification of controlled education, way of implementation and compensation for absences
All laboratory measurements and computer exercises are compulsory. If the student duly apologize his/her absence, missed exercises and measurements could be repeated in agreement with the teacher. The processing and sending of the all assignments in time is compulsory too.
Type of course unit
26 hours, optionally
Teacher / Lecturer
13 hours, optionally
Teacher / Lecturer
Exercise in computer lab
13 hours, compulsory
Teacher / Lecturer
13 hours, compulsory
Teacher / Lecturer