Publications de Satish Babu Korada

Exchange of Limits: Why Iterative Decoding Works

We consider communication over binary-input memoryless output-symmetric channels using low-density parity-check codes and message-passing decoding. The asymptotic (in the length) performance of such a combination for a fixed number of iterations is given b ...

2011

Polar Codes: Characterization of Exponent, Bounds, and Constructions

Rüdiger Urbanke, Satish Babu Korada, Eren Sasoglu

Polar codes were recently introduced by Arikan. They achieve the capacity of arbitrary symmetric binary-input discrete memoryless channels under a low complexity successive cancellation decoding strategy. The original polar code construction is closely rel ...

2010

Tight Bounds on the Capacity of Binary Input random CDMA Systems

Nicolas Macris, Satish Babu Korada

We consider multiple access communication on a binary input additive white Gaussian noise channel using randomly spread code division. For a general class of symmetric distributions for spreading coefficients, in the limit of a large number of users, we pr ...

2010

Polar Codes are Optimal for Lossy Source Coding

Rüdiger Urbanke, Satish Babu Korada

We consider lossy source compression of a binary symmetric source using polar codes and the low-complexity successive encoding algorithm. It was recently shown by Arikan that polar codes achieve the capacity of arbitrary symmetric binary-input discrete mem ...

Institute of Electrical and Electronics Engineers2010

An empirical scaling law for polar codes

Rüdiger Urbanke, Emre Telatar, Andrea Montanari, Satish Babu Korada

IEEE2010

Polar codes for Slepian-Wolf, Wyner-Ziv, and Gelfand-Pinsker

Rüdiger Urbanke, Satish Babu Korada

2010

Polar codes for channel and source coding

Satish Babu Korada

The two central topics of information theory are the compression and the transmission of data. Shannon, in his seminal work, formalized both these problems and determined their fundamental limits. Since then the main goal of coding theory has been to find ...

EPFL2009

Polar Codes: Characterization of Exponent, Bounds, and Constructions

Rüdiger Urbanke, Satish Babu Korada, Eren Sasoglu

Polarization codes were recently introduced by Ar\i kan. They are explicit code constructions which achieve the capacity of arbitrary symmetric binary-input discrete memoryless channels (and even extensions thereof) under a low complexity successive decodi ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2009

Exact Solution of the Gauge Symmetric p-Spin Glass Model on a Complete Graph

Nicolas Macris, Satish Babu Korada

We consider a gauge symmetric version of the p-spin glass model on a complete graph. The gauge symmetry guarantees the absence of replica symmetry breaking and allows to fully use the interpolation scheme of Guerra to rigorously compute the free energy. In ...

2009

Polar Codes are Optimal for Lossy Source Coding

Rüdiger Urbanke, Satish Babu Korada

We consider lossy source compression of a binary symmetric source with Hamming distortion function. We show that polar codes combined with a low-complexity successive cancellation encoding algorithm achieve the rate-distortion bound. The complexity of both ...

2009

Performance of Polar Codes for Channel and Source Coding

Rüdiger Urbanke, Satish Babu Korada, Nadine Hussami

Polar codes, introduced recently by Arikan, are the first family of codes known to achieve capacity of symmetric channels using a low complexity successive cancellation decoder. Although these codes, combined with successive cancellation, are optimal in th ...

2009

A Class of Transformations that Polarize Binary-Input Memory less Channels

Satish Babu Korada, Eren Sasoglu

A generalization of Arikan's polar code construction using transformations of the form G(circle times n) where G is an l x l matrix is considered. Necessary and sufficient conditions are given for these transformations to ensure channel polarization. It is ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2009

On Broadcast with a Common Message over Networks

Dinkar Vasudevan, Satish Babu Korada

We consider the following communication problem over a directed graph. A source node wants to transmit a common message to a set of receiver nodes along with a private message to each of the receivers. We show a class of networks for which the achievable r ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2008

Broadcast and Slepian-Wolf multicast over Aref Networks

Dinkar Vasudevan, Satish Babu Korada

We consider source coding over Aref networks. In particular we consider the following two problems: (i) multicasting correlated sources to a set of receivers, (ii) broadcasting sources to their respective receivers. For the first problem we show necessary ...

2008

Concentration of Magnetization for Linear Block Codes

Nicolas Macris, Shrinivas Kudekar, Satish Babu Korada

We consider communication over the binary erasure and the binary additive white gaussian noise channels using fixed linear block codes and also appropriate ensembles of such codes. We show concentration of the magnetization over the channel realizations an ...

2008

Exchange of Limits: Why Iterative Decoding Works

Rüdiger Urbanke, Satish Babu Korada

We consider communication over binary-input memoryless output-symmetric channels using low-density parity-check codes under MP decoding. The asymptotic (in the length) performance of such a combination for a fixed number of iterations is given by density e ...

2008

Exact solution for the conditional entropy of Poissonian LDPC codes over the Binary Erasure Channel

Nicolas Macris, Shrinivas Kudekar, Satish Babu Korada

We consider communication over a binary erasure channel with low density parity check codes and optimal maximum a posteriori decoding. It is known that the problem of computing the average conditional entropy, over such code ensembles, in the asymptotic li ...

2007

On the Capacity of a Code Division Multiple Access System

Nicolas Macris, Satish Babu Korada

We consider multiuser communication on a binary input additive white Gaussian noise channel using Randomly Spread-Code Division Multiple Access. We show concentration of various quantities of the system including the capacity and the free energy. We also o ...

2007

On the concentration of the capacity for a code division multiple access system

Nicolas Macris, Satish Babu Korada

We prove the concentration of the capacity, in the large system limit, for a code division multiple access system over an additive white Gaussian noise channel, with Gaussian signature sequences and {\it binary input} symbols. The probabilistic tools that ...

2007

Exact Solution of a p-Spin Model and its Relationship to Error Correcting Codes

Nicolas Macris, Satish Babu Korada

2006