Publications by Chien-Yi Wang | EPFL Graph Search

Information-Theoretic Caching: The Multi-User Case

Michael Christoph Gastpar, Chien-Yi Wang, Sung Hoon Lim

In this paper, we consider a cache aided network in which each user is assumed to have individual caches, while upon users’ requests, an update message is sent through a common link to all users. First, we formulate a general information theoretic setting ...

Institute of Electrical and Electronics Engineers2017

A New Converse Bound for Coded Caching

Michael Christoph Gastpar, Chien-Yi Wang, Sung Hoon Lim

An information-theoretic lower bound is developed for the caching system studied by Maddah-Ali and Niesen. By comparing the proposed lower bound with the decentralized coded caching scheme of Maddah-Ali and Niesen, the optimal memory--rate tradeoff is char ...

2016

Information-Theoretic Caching: Sequential Coding for Computing

Michael Christoph Gastpar, Chien-Yi Wang, Sung Hoon Lim

Under the paradigm of caching, partial data are delivered before the actual requests of users are known. In this paper, this problem is modeled as a canonical distributed source coding problem with side information, where the side information represents th ...

Institute of Electrical and Electronics Engineers2016

Information Theoretic Caching: The Multi-User Case

Michael Christoph Gastpar, Chien-Yi Wang, Sung Hoon Lim

In this paper, we present information theoretic inner and outer bounds on the fundamental tradeoff between cache memory size and update rate in a multi-user cache network. Each user is assumed to have individual caches, while upon users’ requests, an updat ...

Ieee2016

Information-Theoretic Caching

Michael Christoph Gastpar, Chien-Yi Wang, Sung Hoon Lim

Motivated by the caching problem introduced by Maddah-Ali and Niesen, a problem of distributed source coding with side information is formulated, which captures a distinct interesting aspect of caching. For the single-user case, a single-letter characteriz ...

2015

Interactive Computation of Type-Threshold Functions in Collocated Gaussian Networks

Michael Christoph Gastpar, Chien-Yi Wang

In wireless sensor networks, various applications involve learning one or multiple functions of the measurements observed by sensors, rather than the measurements themselves. This paper focuses on the class of type-threshold functions, e.g., the maximum an ...

Institute of Electrical and Electronics Engineers2015

Function Computation over Networks : Efficient Information Processing for Cache and Sensor Applications

Chien-Yi Wang

This thesis looks at efficient information processing for two network applications: content delivery with caching and collecting summary statistics in wireless sensor networks. Both applications are studied under the same paradigm: function computation ove ...

EPFL2015

Approximate Ergodic Capacity of a Class of Fading Two-User Two-Hop Networks

Michael Christoph Gastpar, Chien-Yi Wang

The fading AWGN two-user two-hop network is considered where the channel coefficients are independent and identically distributed (i.i.d.) according to a continuous distribution and vary over time. For a broad class of channel distributions, the ergodic su ...

Institute of Electrical and Electronics Engineers2014

On Distributed Successive Refinement with Lossless Recovery

Michael Christoph Gastpar, Chien-Yi Wang

The problem of successive refinement in distributed source coding and in joint source-channel coding is considered. The emphasis is placed on the case where the sources have to be recovered losslessly in the second stage. In distributed source coding, it i ...

2014

Computation Over Gaussian Networks With Orthogonal Components

Michael Christoph Gastpar, Chien-Yi Wang

Function computation over Gaussian networks with orthogonal components is studied for arbitrarily correlated discrete memoryless sources. Two classes of functions are considered: 1) the arithmetic sum function and 2) the type function. The arithmetic sum f ...

Institute of Electrical and Electronics Engineers2014

Multi-round computation of type-threshold functions in collocated Gaussian networks

Michael Christoph Gastpar, Chien-Yi Wang

In wireless sensor networks, various applications involve learning one or multiple functions of the measurements observed by sensors, rather than the measurements themselves. This paper focuses on the computation of type-threshold functions which include t ...

2013

Computation over Gaussian networks with orthogonal components

Michael Christoph Gastpar, Chien-Yi Wang

Function computation of arbitrarily correlated discrete sources over Gaussian networks with multiple access components but no broadcast is studied. Two classes of functions are considered: the arithmetic sum function and the frequency histogram function. T ...

2013

Approximate Ergodic Capacity of a Class of Fading 2-user 2-hop Networks

Michael Christoph Gastpar, Chien-Yi Wang

We consider a fading AWGN 2-user 2-hop network in which the channel coefficients are independently and identically distributed (i.i.d.) drawn from a continuous distribution and vary over time. For a broad class of channel distributions, we characterize the ...

Ieee2012