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Capacité d'un canal

La capacité d'un canal, en génie électrique, en informatique et en théorie de l'information, est la limite supérieure étroite du débit auquel l'information peut être transmise de manière fiable sur un canal de communication. Suivant les termes du théorème de codage du canal bruyant, la capacité d'un canal donné est le débit d'information le plus élevé (en unités d'information par unité de temps) qui peut être atteint avec une probabilité d'erreur arbitrairement faible. La théorie de l'information, développée par Claude E. Shannon en 1948, définit la notion de capacité de canal et fournit un modèle mathématique permettant de la calculer. Le résultat clé stipule que la capacité du canal, telle que définie ci-dessus, est donnée par le débit maximum de l'information mutuelle entre l'entrée et la sortie du canal, où la maximisation se fait par rapport à la distribution de l'entrée. La notion de capacité du canal a été au cœur du développement des systèmes de communication modernes, filaires et sans fil, avec l'avènement de nouveaux mécanismes de codage de correction d'erreurs qui ont permis d'atteindre des performances très proches des limites promises par la capacité du canal. Bande passante Débit binaire Néguentropie Redondance Expéditeur, compression de données, récepteur Théorème de Shannon-Hartley Efficacité spectrale Throughput MIMO László Lovász (1979), « On the Shannon Capacity of a Graph », IEEE Transactions on Information Theory, IT-25 (1): 1–7, doi: 10.1109/tit.1979.1055985. Thomas M. Cover ; Joy A. Thomas (2006). « Chapter 7: Channel Capacity ». Elements of Information Theory (Second ed.). Wiley-Interscience. pp. 206–207. . Thomas M. Cover, Joy A. Thomas (2006). Elements of Information Theory. John Wiley & Sons, New York. . David Tse, Pramod Viswanath (2005), Fundamentals of Wireless Communication, Cambridge University Press, UK, . The Handbook of Electrical Engineering. Research & Education Association. 1996. p. D-149. . Catégorie:Théorie de l'information Catégorie:Théorie des télécommunications Catégori

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Exercices associés (4)

Tube irrégulier

An incompressible liquid circulates in a tube. At a certain location, the section of the tube strongly decreases (cf. figure). The continuity equation indicates us that :

\frac{\partial\rho}{\partial t} + \nabla\cdot \rho \vec{v} = 0~.

Show that this is equivalent to the simpler equation:

\quad \langle v_n\rangle=\frac{1}{S_n}\iint_{S_n}\vec{v}\cdot d\vec{\sigma} ~.$$ If we add to the figure the velocity vectors as well as the vect

Excitation d un oscillateur harmonique vertical

A mass m is suspended on a spring of natural length l₀ and of elastic constant k. The spring is attached to a piston. The vertical motion of the piston is described by the equation s(t)u2004=u2004s₀cosu2006(ωt)xa0.

Give explicit expressions for the external forces and determine the equation of motion.
Show that the equation of motion can be recast as, $\ddot{x}\left(t\right) + c_1\,x\left(t\right) = c_1\,s\left(t\right)\ ,$ where x(t)u2004=u2004z(t)u2005+u2005c₂ with z(t) the vertica

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A few days after the events narrated in the famous fable[1], the crow and the fox meet again. Having learned from its mistakes, the crow is determined not to be fooled again by the fox’s flattery. The fox, however, is set on getting a second piece of cheese. This time , it chooses a more direct method and throws a stone at the crow to scare it. It works beyond expectations: as soon as the stone is thrown, the crow drops the cheese. The crow is perched on a tree of height H; the fox is a distance L from the

Modèle de choc élastique

A chariot considered as a material point of mass m moves without friction on an horizontal plane; a spring of constant k is mounted at one end of the chariot. Through this spring, the chariot that has a speed v₀, collides with a fixed wall (considered as having an infinite mass); the spring first contracts, then expands, and the chariot moves in the opposite direction. We assume that the collision is perfectly elastic, i.e. the mechanical energy is conserved.

Determine the time interval Δt during which

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Understanding the Haar Basis for Grayscale Image Compression

A Basis for Grayscale Images[1]¶

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Fairness Week 2: COMPAS and Fairness in Machine Learning – Solutions

Fairness Week 2: Predicting recidivism¶{.anchor-link} {#Fairness-Week-2:-Predicting-recidivism}

How to use this notebook Simply read the text and follow the instructions.
This notebook contains code cells, which can be modified and must be executed to see the result of their content.
To execute a cell, select it and click on the play button (▶) in the tool bar, or type Shift + Enter or Ctr + Enter. As the variables contained in a cell are stor

Exercices associés (4)

Tube irrégulier

An incompressible liquid circulates in a tube. At a certain location, the section of the tube strongly decreases (cf. figure). The continuity equation indicates us that :

\frac{\partial\rho}{\partial t} + \nabla\cdot \rho \vec{v} = 0~.

Show that this is equivalent to the simpler equation:

\quad \langle v_n\rangle=\frac{1}{S_n}\iint_{S_n}\vec{v}\cdot d\vec{\sigma} ~.$$ If we add to the figure the velocity vectors as well as the vect

Excitation d un oscillateur harmonique vertical

Give explicit expressions for the external forces and determine the equation of motion.
Show that the equation of motion can be recast as, $\ddot{x}\left(t\right) + c_1\,x\left(t\right) = c_1\,s\left(t\right)\ ,$ where x(t)u2004=u2004z(t)u2005+u2005c₂ with z(t) the vertica

Le corbeau et le renard

Modèle de choc élastique

Determine the time interval Δt during which

Capacité d'un canal

Chattez avec Graph Search

Fairness Week 2: Predicting recidivism¶{.anchor-link} {#Fairness-Week-2:-Predicting-recidivism}

Fairness Week 2: Predicting recidivism¶{.anchor-link} {#Fairness-Week-2:-Predicting-recidivism}

Informative yet compact monitoring for building retrofits: Joint information entropy–based measurement system design applied to a real office building

A Finite-Sample Strong Converse for Binary Hypothesis Testing via (Reverse) Rényi Divergence

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