Digital communications


Digital communications is the study of physical layer transmission and reception strategies in communications equipment such as mobile communication devices, high-speed ethernet, optical communications and subscriber-line communications. It comprises the areas of (i) statistical modelling of communication channels (ii) design of coding and modulation systems for error resiliency (iii) design of demodulation and decoding strategies and the associated methods for assessing their performance. In addition to providing an overview of communication channels and classical modulation strategies, this course takes a hands-on approach by focusing on the details of a few critical elements of digital communications pertaining to modern wireless transceivers, both coherent and non-coherent.

Teaching and Learning Methods :: Lectures and hands-on lab sessions in MATLAB using signals acquired from local 4G networks.

Course Policies : Attendance to lab sessions is mandatory.




.1. Elements of a digital communication system: Coding, Modulation, Communication channels, Maximum-Likelihood Receivers 2. Basic mathematics required for the analysis and design of digital communication sysetms

                a) Definitions of Energy and Power signals (deterministic and random)

                b) statistical characterization of noise processes

                c) Orthonormal Projections and Shannon Sampling

                d) decision theory

3. Common modulation formats and associated maximum-likelihood receivers

                a) coherent reception

                b) non-coherent reception

4. OFDM transceivers

Lab Sessions. All lab sessions are carried out using signal acquisitions done during the lab sessions with the students using live 4G LTE signals transmitted in the vicinity of EURECOM. The students will be able to work with highly realistic digitized broadband radio signals in order to understand the difficulties of building a digital radio receiver. The receivers are built in an offline (i.e. non real-time) MATLAB environment.

                Lab session A) Non-coherent reception of the 4G Primary Synchronization Signal. This lab session highlights time-domain non-coherent reception procedures for a ternary-modulated signal along with the basic procedures of time and frequency synchronization.

                Lab session B) quasi-coherent reception of the 4G Secondary Synchronization Signal. This lab session highlights frequency-domain OFDM deframing, channel estimation, maximum-likelihood reception of an M-ary waveform.

                Lab session C) Demodulation of the Physical Broadcast channel. This lab session highlights more complex frequency-domain OFDM deframing, channel estimation for multi-antenna transmission and maximum-likelihood reception of the Alamouti space-time code.

Learning outcomes:

The students obtain a solid understanding of a modern OFDM (orthogonal frequency-division multiplexing) transmission and reception system. This should serve as a basis for understanding the jargon used in technical documents (e.g. standardization) pertaining to the transmission component of many current communication systems. For most, it will also serve as a first experience in modern digital transceiver design.

Nb hours : 42 , 21 hours of lab sessions.

Grading Policy : 50% final exam, 50% grading lab session.