Digital Communications - 4PMICNU1

Goal(s)

The main objective is to give the basic principle of digital transmission, consisting in sending digital information into physical (analog) channel, ans see current basic techniques. I uses Information Theory results (C. Shannon) to give and interpret achievable performance and position the performance of basic modulations techniques (especially in terms of spectral efficiency and energy efficiency trade-offs). Other objective is to briefly present gives also a brief introduction of present radio-frequency transmission systems (e.g. : Mobile communication).

Content(s)

1. Base-band digital transmission

• line code : M-ary modulation with orthogonal Dictionnaries, Linear Modulations (Pulse-amplitude Modulations), general properties (power, power spectrum density, euclidian distance, energy and spectral efficiencies)
• Performance over AWGN channel case: Matched filter (Correlator), Nyquist criteria (Free Inter-Symbol-Interference criterion)
  2. Carrier frequency digital transmission :
  -Digital modulation : I/Q modulation-demodulation, linear (phase, amplitude, quadrature-amplitude) modulations,
  -Coherent reception (AWGN case): detection theory, performances (bit error rate, spectral efficiency, distance from information theory),

3. Radio transmission systems :
General information about transmission systems (microwave links, satellite links, and radio-mobile communications, introduction to advances transmissions techniques such as CDMA (used in UMTS, ...) and OFDM (used in DVB, TNT, ...).

Part 1 will be treated in depth, while Parts 2 and 3 will be seen only briefly as extensions.

The course will be illustrated by classic Classworks as well as by Labworks sessions. The latter will consist of a guided mini-project consisting of developing a digital communication simulation chain and interpreting the results directly linked to the course. This will will result in the redaction of a report which will be noted (1/3 of the overall mark).

• Basic of Deterministic signal Processing (Analog and Digital)
• Basic of Random Signal Processing (Stationry stochastic process, Correlation and Spectrum, White Gaussian Noise)