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ELEC60007 Communication Systems


Lecturer(s): Prof Athanassios Manikas

Aims

1) To provide the foundations of a typical wireless Digital Communication System (DCS) and overview its operation.

2) To define the main performance criteria for wireless-DCS and map DCS on “parameter-planes”, with emphasis given to the Energy Utilisation Efficiency and Bandwidth Utilisation Efficiency.

3) To identify the theoretical limits in the performance of wireless-DCS

4) To highlight system trade-offs

5) To extend a conventional wireless-DCS to spread spectrum and multi-carrier systems

6) To provide the foundations of a typical 3G/4G/5G wireless System and overview its operation.

Learning Outcomes


To model, design and analyse modern wireline and wireless Digital Communication Systems

Syllabus

Lecturer(s): Prof Thanassis Manikas

Aims:


1) INTRODUCTORY CONCEPTS: Signal Bandwidth, Auto-correlation, Cross-correlation, Parseval's Theorem, Wiener-Khinchin Theorem, Woodword's Notation and Fourier Transform, AWGN, Tail function.

2) INFORMATION SOURCES: Classification of Information Sources, Discrete Memoryless Sources, Source Entropy, Source Information rate, Joint DMS Sources, Markov Discrete Information Source, Continuous Sources, Measure of Information Generated by a Continuous Source, Gaussian Sources, Entropy Power, Information Sink.

3) COMMUNICATION CHANNELS: Discrete and Continuous Channels, Converting a Continuous to a Discrete Channel, Mutual Information and Equivocation, Capacity of a Channel, Shannon's Capacity Theorem for AWGN and non-Gaussian Channel, Channel Bandwidth and Symbol Rate.

4) WIRELESS COMMS/CHANNELS: Multipaths, Wireless Systems Classification, Wireless SISO (Single-Input, Single-Output) Channels (Propagation Loss, Fading, Delay Spread, Frequency Selective and Frequency Flat Channels, Channel Selectivity and Channel Coherence, Scatterers, Fading and Path Gain/Loss, Log-distance Path-Loss Model, Log-Normal Distribution, Rayleigh, Ricean and Uniform Distributions, Nakagami Distribution, Clusters), Impulse Response of a SISO Channel.

5) PERFORMANCE CRITERIA & LIMITS: introductory concepts, Energy Utilisation Efficiency (EUE), Bandwidth Utilisation Efficiency (BUE), bandwidth expansion factor, signal-to-noise power ration (SNR), probability of error. Shannon's threshold capacity curve, theoretical limits on performance of digital communication systems and the concept of an ideal communication system. The (Pe/SNR, EUE, BUE) parameter planes. Representations of the major communication systems on the parameter planes. Comments, comparisons and discussions. Connection and with Shannon's first coding theorem, Channel capacity and Shannon's second coding theorem. SNR at the output of an “ideal” communication system.


6) DIGITAL MODULATORS/DEMODULATIONS & LINE CODES: Various modellings of digital modulators, constellation diagram of binary and M-ary Systems, examples (M-ary ASK, M-ary PSK, M-ary FSK, QAM. Main types of Line Codes, their autocorrelation function and PSD(f). Examples of connecting systems with Line Codes (wireline Comms),

7) DECISION THEORY: Hypothesis testing, optimum decision criteria, examples. Optimum receiver architectures based on decision criteria. Equivalent optimum architectures using Signal Constellation, Symbol-Error-Rate and Bit-error-rate of binary and M-ary optimum systems.

8) PN-SEQUENCES and PN-SIGNALS: Galois field GF(2) basic theory, shift registers, basic properties of m-sequences, statistical properties of m-sequences, Gold sequences.
Modelling, cross/auto correlation functions and power spectral density of PN-Signals.

9) PRINCIPLES of SPREAD SPECTRUM THEORY and SYSTEMS (SSS): Basic concepts and parameters. Classification and modelling of jammers. Modelling of BPSK and QPSK Direct Sequence SSS in a jamming environment, estimation of SNIR and bit-error-probability. Direct sequence SSS on the (SNR/pe, EUE,BUE) parameter plane. Frequency Hopping SSS.

10) PRINCIPLES OF PCM and PSTN: using concepts and analytical tools presented in the previous topics, the examination of multiplexing and PSTN will be presented, based on the CCITT recommendations for PCM and the associated digital hierarchy. This will include maximum-SNR-non-uniform quantisers, A-law and mu-law companders, differential quantisers, basic concepts of differential PCM.

11) PRINCIPLES of 3G (CDMA), 4G (OFDMA) and 5G (NR): 3GPP, FDD, TDD, Channel Reuse and Reuse Distance, Signal Overlay. 3G Specifications, QPSK1 and QPSK2, Channelisation and Scrambling Codes. Basics of CDMA. Analysis of a DS-CDMA system (bit error rate as a function of EUE, number of users, power control, voice activity factor and sectorisation).
4G: OFDM, OFDMA, SC-FFDMA. 5G: IMT2020, Spinder Diagram, Triangle Diagram, specification and main characteristics, New Radio (NR).

Assessment
Exam Duration: 3:00hrs
Coursework contribution: 20%

Term: Autumn

Closed or Open Book (end of year exam): Closed

Coursework Requirement:
         Laboratory Experiment
         Assessed problem sheets

Oral Exam Required (as final assessment): no

Prerequisite module(s): None required

Course Homepage: http://skynet.ee.ic.ac.uk/notes/notes.html

Book List: