Theory of Communication
FEKT-NTSDAcad. 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 lectures 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 professional trainings 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
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)
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)
Planned learning activities and teaching methods
Teaching methods comprehend lectures, computer exercises, laboratory measurements and professional trainings. The MATLAB software is used for computer exercises. Laboratory measurements proceed with the aid of specially prepared electronic instruments, Agilent 33220A generators and Tektronix TDS 2002 scopes. Professional trainings are focused on computation of practical examples from the field of communication and data transmission.
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 10 points for all laboratory measurements, during them student always obtain points at the end of each lesson when teacher verify correctness of results measured and conclusions stated in the given protocol,
- up to 10 points for the professional trainings according to the result of written examination of student’s knowledge which is usually in the program of the 5th training,
- up to 10 points for all computer exercises, during them student obtain points for correctly processed tasks,
- up to 70 points for compulsory exam, which has a written form and only students who passed all laboratory measurements and professional trainings 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. Basic waveform representations of binary digits. Line codes.
2) Digital communication system. Mediums for data transfer.
3) Noise in communication systems. Receiving of noised signal.
4) Amplitude and frequency modulations and keyings.
5) Phase modulation and keying. Problems of BPSK data transfer.
6) Digital modulations with harmonic carrier (QPSK, 8PSK, O-QPSK, MSK, FFSK, GMSK).
7) Digital modulations with harmonic carrier (π/4-DQPSK, 8PSK, MQAM, CAP).
8) Reduction of intersymbol interference (ISI). Equalizers. Synchronization. Scrambling.
9) Synchronization. Scrambling. Methods of error control. Pulse modulations (PAM, PWM, PDM, PPM).
10) Digital representations of analog signals. Quantization. Pulse coded modulations (PCM, DPCM, DM, SDM).
11) Multiplexing and multiple access. Orthogonal frequency division multiplex (OFDM).
12) Modulations in optoelectronics. Effect of the noise in passband.
13) Introduction to the information theory. Coding. 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.
Specification of controlled education, way of implementation and compensation for absences
All laboratory measurements and professional trainings are compulsory. If the student duly apologize his/her absence, missed exercises, measurements and trainings could be repeated in agreement with the teacher, usually at the last week of the teaching period.
Type of course unit
39 hours, optionally
Teacher / Lecturer
13 hours, optionally
Teacher / Lecturer
Exercise in computer lab
13 hours, compulsory
Teacher / Lecturer
13 hours, compulsory
Teacher / Lecturer