Sufficiency in Statistical Signal Processing

The course aims to provide students with the necessary knowledge about the systems for transmission and reception of information in digital form and over a real communication channel.

Learning Outcomes.

Knowledge and understanding

After the course the student should understand the following aspects of digital communication systems

* Performances of modulation formats.

* Channel capacity and channel coding techniques.

* Equalization techniques for band-limited channels.

* Countermeasures against Fading channels

Applying knowledge and understanding

After the course the student should be able to

* Compute the probability of error of a digital modulation scheme.

* Design optimum and sub-otimum receivers  for digital communications.

* Design adaptive equalizers to combat intersymbol interference and fading.

Making judgements

Students should acquire the ability to compare pros and cons of different approaches to the solution of a specific problem through examples and problems.

Communication

The ability to communicate on technical topics should be acquired by discussing in a rigorous way not only concepts and tools of digital communications, but also the adopted solution to a specific problem.

Learning skills

Selected problems will be proposed that require elaborating on introduced concepts and methods, also with the help of selected readings suggested by the instructor (from the list of references). Identifying solutions to non trivial problems will be  important to be ready for autonomous lifelong learning.

Classroom lectures given by the instructor using the board.

Oral. The student must answer to 3 questions about the entire course syllabus; each question is worth 10/30 for a total of 30/30. Examination time is between 30 and 60 minutes.

Office Hours: By appointment; contact the instructor by E-Mail (francesco.bandiera@unisalento.it), Telegram (@francescobandiera) or at the end of class meetings.

Course Contents

Part I – Introduction. Summary about digital modulation schemes. Linear modulations (PAM, PSK, QAM) and orthogonal modulations (FSK, PPM). Bandwidth efficiency, power efficiency, comparisons. Probability of error of M-PAM and M-FSK. Union bound on the probability of error. Non coherent FSK: optimum receiver design and bandwidth requirements. Qualitative performance assessment. (11 hours).

Part I - Channel Capacity and Channel Coding. Channel models and capacity. Channel coding theorem. Linear block codes. Hamming codes. Cyclic codes. Performance analysis of coded systems. Hard and soft decoding. Interleaving. Convolutional Codes. Block-diagram of the encoder. Representations: tree, trellis, state-diagram, transfer function. Decoding: maximum likelihood sequence detector and Viterbi algorithm. Performance analysis with soft and hard decisions decoding. (30 hours)

Part III - Digital Transmission over real channels. Design of communication systems for the bandlimited channel. Channel models. Inter Symbols Interference (ISI). Nyquist criterion and eye diagram. Equalization. The optimum receiver for channels with ISI: maximum likelihood sequence detector and Viterbi algorithm revisited. Performance analysis. Linear equalization methods: zero forcing (ZF) and minimum mean squared error (MMSE). Performance analysis. Non linear equalizers (decision-feedback). Adaptive Equalization. Adaptive linear equalizers: ZF, least mean squares (LMS), recursive least squares (RLS). Convergence properties and performance analysis. Blind equalization: maximum likelihood, per survivor processing, multiple signals classification (MUSIC). Digital Transmission over Multipath Fading Channels. Channel Models and classification. Channel selectivity in time and/or frequency. Transmission of digitally-modulated signals over the flat/flat channel: diversity reception techniques and performance analysis. Digital transmission over the frequency-selective fading channel: RAKE receiver and its performance. Adaptive implementations. (40 hours)

[1] J. G. Proakis, “Digital Communications”, McGraw Hill, 4th Ed., 2004.

[2] J. M. Wozencraft, I. M. Jacobs, “Principles of Communication Engineering,” Waveland Press (reprint 1990).

Other useful references

-         J. G. Proakis M. Salehi, “Digital Communications,” McGraw Hill, 5th Ed., 2008.

-         T. M. Cover, J. A. Thomas, “Elements of Information Theory,” Wiley, 1991.

-         A. H. Sayed, “Fundamentals of Adaptive Filtering,” John Wiley and Sons, 2003.

-         V. Pless, “Introduction to the Theory of Error-Correcting Codes,” Wiley, 1998.

 

-         Scientific papers highlighted by the instructor.