Publications by Rüdiger Urbanke

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We analyze iterative coding for the frame-synchronous binary-input discrete-time Gaussian multiple access channel. Using the method of Density Evolution, we optimize degree distributions to exhibit code ensembles whose iterative decoding thresholds are only few tenths of dB away from the Shannon limit.

We determine the stability condition of low-density parity-check codes under both bitwise and blockwise maximum a posteriori decoding. As a consequence, we prove that the stability condition determines an upper bound on both the bitwise and the blockwise m ...

We consider the asymptotic behavior of the polarization process for polar codes when the blocklength tends to infinity. In particular, we study the asymptotics of the cumulative distribution P(Z(n)

We consider chains of random constraint satisfaction models that are spatially coupled across a finite window along the chain direction. We investigate their phase diagram at zero temperature using the survey propagation formalism and the interpolation met ...

Modern machine learning models with very high accuracy have been shown to be vulnerable to small, adversarially chosen perturbations of the input. Given black-box access to a high-accuracy classifier f, we show how to construct a new classifier g that has ...

In this paper we investigate the behaviour of iteratively decoded low-density parity-check codes over the binary erasure channel in the so-called "waterfall region". We show that, according to a simplified model, the performance curves in this region follow a very basic scaling law. This scaling law together with the error floor expressions developed previously can be used for fast finite-length optimization of low-density parity-check codes.

We study the stability of low-density parity-check codes under blockwise or bitwise maximum a posteriori decoding, where transmission takes place over a binary-input memoryless output-symmetric channel. Our study stems from the consideration of constructin ...

We present a coding paradigm that provides a new achievable rate for the primitive relay channel by combining compress-and-forward and decode-and-forward with a chaining construction. In the primitive relay channel model, the source broadcasts a message to ...

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 ...

We present polar coding schemes for the 2-user discrete memoryless broadcast channel (DM-BC) which achieve Marton's region with both common and private messages. This is the best achievable rate region up to date, and it is tight for all classes of 2-user ...

We study the capacity regions of various broadband degraded broadcast channels including the degraded Poisson broadcast channel and the degraded very-noisy broadcast channel. It is shown that in the absence of dark current the capacity region of the degraded Poisson broadcast channel is achievable with a simple time-sharing strategy, and an analogous result is proved for the degraded very-noisy broadcast channel with binary inputs. Conditions are derived for time-sharing to be optimal for a general degraded

Machine unlearning is essential for meeting legal obligations such as the right to be forgotten, which requires the removal of specific data from machine learning models upon request. While several approaches to unlearning have been proposed, existing solutions often struggle with efficiency and, more critically, with the verification of unlearning—particularly in the case of weak unlearning guarantees, where verification remains an open challenge. We introduce a generalized variant of the standard unlearni

We derive the average weight distribution function and its asymptotic growth rate for low-density parity-check (LDPC) code ensembles. We show that the growth rate of the minimum distance of LDPC codes depends only on the degree distribution pair. It turns ...

We consider lossy compression of a binary symmetric source by means of a low-density generator-matrix code. We derive two lower bounds on the rate distortion function which are valid for any low-density generator-matrix code with a given node degree distri ...

Privacy in federated learning is crucial, encompassing two key aspects: safeguarding the privacy of clients' data and maintaining the privacy of the federator's objective from the clients. While the first aspect has been extensively studied, the second has ...

Potential functionals have been introduced recently as an important tool for the analysis of coupled scalar systems (e.g. density evolution equations). In this contribution we investigate interesting properties of this potential. Using the tool of displace ...

Rüdiger Urbanke

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Achieving General Points in the 2-User Gaussian MAC Without Time-Sharing or Rate-Splitting by Means of Iterative Coding

The Stability Condition of LDPC Codes Under MAP Decoding

On the scaling of polar codes: I. The behavior of polarized channels

Threshold Saturation in Spatially Coupled Constraint Satisfaction Problems

Constructing a provably adversarially-robust classifier from a high accuracy one

Finite-Length Scaling for Iteratively Decoded LDPC Ensembles

The Stability of Low-Density Parity-Check Codes and Some of its Consequences

Maximum a posteriori decoding and turbo codes for general memoryless channels

A New Coding Paradigm for the Primitive Relay Channel

Performance of Polar Codes for Channel and Source Coding

Achieving Marton's Region for Broadcast Channels Using Polar Codes

On Wide Band Broadcast Channels

Efficient Machine Unlearning by Model Splitting and Core Sample Selection

Weight Distribution of Low-Density Parity-Check Codes

Lower Bounds on the Rate-Distortion Function of Individual LDGM Codes

Correction to “Multiple-Antenna Signal Constellations for Fading Channels”

Capacity-achieving ensembles for the binary erasure channel with bounded complexity

Federated One-Shot Learning with Data Privacy and Objective-Hiding

Finite-Length Scaling for Iteratively Decoded LDPC Ensembles

Analysis of Coupled Scalar Systems by Displacement Convexity