Past Events

TBA

I discuss the family of methods known under the names of BeliefPropagation (BP) in artificial intelligence, Message Passing(MP) in computer science/information theory, and Bethe-Peierls(still BP) approximation in statistical physics. These BP/MPmethods offer efficient and distributed algorithmic solutions,along with rich theoretical guarantees, for variety of problemsin statistical inference and optimization. The power of BP/MPwill be illustrated on examples from error-correction, particletracking in fluid mechanics and switching control over powergrids.

Gossip algorithms are a class of decentralized solutions to theproblem of achieving consensus in a network of agents. Theyhave attracted recent research interest because they are simpleand robust -- attractive qualities for wireless ad-hoc and sensornetworks. Unfortunately, the standard gossip protocol convergesvery slowly for many popular network models. I will discuss threeways to leverage properties of the network to achieve fasterconvergence : routing, broadcast, and mobility. Joint work with Alex G. Dimakis, Tuncer Can Aysal, Mehmet ErcanYildiz, Martin Wainwright, and Anna Scaglione.

WiMAX 2 is a key component of the 4G wireless system. Among many new techniques adoptedin WiMAX 2, transmit beamforming plays an essential role in delivering mobile broadbandservice reliably over an extended coverage. It enhances the received signal quality byexploiting the channel knowledge at the transmitter. In practice, channel feedback isrequired for the base station to acquire the channel knowledge. Since the channelfeedback consumes a large overhead, several schemes were proposed in the IEEE 802.16mtask group for efficient feedback.

Summary: In this talk we will present a brief overview of the MIMAX project, whose goal is to develop a compact and low-power consuming RF-MIMO transceiver, which performs adaptive signal combining in the radio-frequency (RF) domain. Assuming perfect channel knowledge, we will consider in detail the problem of designing the transmit and receive RF beamformers under orthogonal frequency division multiplexing (OFDM) transmissions.

Abstract:Radio frequency interference (RFI) is a key limiting factor in communication performance of Wi-Fi, WiMax, cellular, and other wireless data communication systems. Sources of RFI include 1. other wireless users/services operating in the same frequency band, a.k.a. co-channel interference, 2. nearby electronic equipment, such as microwave ovens radiating in the 2.4 GHz band, and 3. the computational platform itself, including clock circuitry and power saving subsystems in laptops and notebooks.

Abstract In this talk we will present a fundamental role that directed information and causal conditioning has in communication with feedback, gambling with causal side information and estimation.We will begin by defining and establishing some key properties of the notions of causal conditioning and directed information.

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Abstract:The design goal of communication networks is to transport information from a generating source to an intended destination. Of the many ways this can be accomplished, there are networks designed to maximize properly selected optimality criteria. This talk is concerned with basic principles governing the associated optimization problem for wireless communication networks in the presence of fading.

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