The course Modern Digital Communication Techniques in taught in IIT Kharagpur as a 4 credit (4 hrs / week) core subject in the Masters program of Telecommunications systems engineering in the department of Electronics and Electrical Communication Engineering. It is taken in the first semester by master degree students, PhD students and Masters by research students. It is also taken as elective by final year UG students. It is also taken as a core subject by Dual degree students who specialize in the field of communication engineering.

Digital communications has had one of the most profound influences in the development of the mankind. It is behind the success of today’s networked society. The objective of this course is to present the engineering principles, theories and practices, which are fundamental to the successful design of a digital communication system.

 

UNIT I

Digitization Techniques for Analog Messages: Introduction - Importance of Digitization Techniques, Elements of Pulse Code Modulation (PCM) - Generation and Reconstruction, Quantization and Coding, Quantization Error, PCM with Noise, Companding in PCM, Time Division Multiplexing(TDM), Delta Modulation, Adaptive Delta Modulation, Differential PCM Systems (DPCM), Adaptive Differential PCM Systems.

 

UNIT II

Base Band Digital Transmission: Digital Signals and Systems – Digital PAM Signals, Transmission Limitations, Power Spectra of Digital PAM, Noise and Errors – Binary Error Probabilities, Matched Filtering, Optimum Filtering. Raised Cosine Filter & Its Spectrum. Eye Diagrams, Zero ISI and Controlled ISI: Conditions on the shape of the pulse and data rate.

 

UNIT III

Band Pass Digital Transmission: Digital Modulation Formats, Coherent Binary Modulation Techniques: Coherent Binary ASK, Coherent BPSK and Coherent BFSK, Coherent Quadrature Modulation Techniques: Coherent QPSK, Error Probability calculation of BASK, BPSK, BFSK, Signal Space representation of BPSK, BFSK, QPSK, Non Coherent Binary Modulation Techniques: Non-Coherent ASK, Non-Coherent FSK, DPSK. Introduction to M-ary Modulation Techniques.

 

UNIT IV

Information Theory: Uncertainty, Information and Entropy, Source Coding Theorem, Huffman Coding: Binary and Ternary; Shannon-Fano Coding; Discrete Memory-less Channels, Mutual Information, Channel Capacity, Channel Coding Theorem, Differential Entropy and Mutual Information for Continuous Ensembles, Channel Capacity Theorem.  

 

UNIT V

Channel Coding-I: Linear Block Codes: Matrix Representation of Linear Block Codes, Syndrome Decoding, Minimum Distance Considerations; Error Detection and Correction of Linear Block Codes;  Hamming codes, Numerical Problems ; Forward Error Correction Systems,  Automatic Retransmission Query (ARQ) systems,Cyclic Codes: Generator Polynomial for the Cyclic Codes, Parity Check Polynomial, Encoder for Cyclic Codes, Calculation of the Syndrome, Introduction to Cyclic Redundancy Check (CRC) Codes,  Numerical Problems in CRC.

UNIT VI

Channel Coding-II: Convolution Codes: Encoding of Convolution Codes using Time DomainApproach and Transform Domain Approach, Code Tree, Trellis Diagram and State Diagram, Maximum-likelihood Decoding of Convolution Codes – Viterbi Algorithm;. Low Density Parity Check (LDPC) Codes, Brief Introduction to Polar Codes;

TEXT BOOKS:

1.  A. Bruce Carlson, & Paul B. Crilly, “Communication Systems – An Introduction to Signals & Noise in Electrical Communication”, McGraw-Hill International Edition, 5th    Edition, 2010.

2.  Digital Communications - Simon Haykin, John Wiley, 2005.

REFERENCES:

• Herbert Taub& Donald L Schilling, “Principles of Communication Systems”, Tata  McGraw-Hill, 3rd Edition, 2009.

• Digital Communications – John Proakis, TMH, 1983.  Communication Systems Analog & Digital – Singh &Sapre, TMH, 2004.

 Digital Communications by Bernard Sklar, Tata McGraw Hill,