ComNum - Séminaires

Le 06/06/2019 [ComNum seminar] Wireless Networks via the Cloud: An Information Theoretic View

Auteur(s) & Affilliation(s) du séminaire :

Prof. Shlomo Shamai

Présentation du séminaire :


at 11am in Amphi Grenat


Abstract:  


Cloud based wireless networks named also as Cloud Radio Access Networks (C-RANs) emerge as appealing architectures for next-generation wireless/cellular systems whereby the processing/encoding/decoding is migrated from the local base-stations/radio units (RUs) to a control/central units (CU) in the "cloud". The network operates via fronthaul digital links connecting the CU and the RUs (operating as relays). The uplink and downlink are examined from a network information theoretic perspective, with emphasis of simple oblivious processing at the RUs, which is attractive also from the practical point of view. The analytic approach, applied to simple wireless/cellular models illustrates the considerable performance gains associated with advanced network information theoretically inspired techniques, carrying also practical implications. An outlook, pointing out interesting theoretical directions, referring also to Fog radio access networks (F-RAN), concludes the presentation.

Biography:

Professor Shlomo Shamai is a distinguished professor at the Department of Electrical engineering at the Technion ? Israel Institute of Technology. Professor Shamai is an information theorist and winner of the 2011 Shannon Award. Shlomo Shamai received the B.Sc., M.Sc., and Ph.D. degrees in electrical engineering from the Technion, in 1975, 1981 and 1986 respectively. During 1975-1985 he was with the Israeli Communications Research Labs. Since 1986 he is with the Department of Electrical Engineering at the Technion?Israel Institute of Technology, where he is now the William Fondiller Professor of Telecommunications. His research areas cover a wide spectrum of topics in information theory and statistical communications. Prof. Shamai is an IEEE Fellow and a member of the International Union of Radio Science (URSI

Contact(s) :

Le 23/05/2019 [ComNum PhD's seminar] Compression with random access

Auteur(s) & Affilliation(s) du séminaire :

Shashank Vatedka

Présentation du séminaire :

at 1pm in A301


Abstract:

In compressing large files, it is often desirable to be able to efficiently recover and update short fragments of data. Classical compression schemes such as Lempel-Ziv are optimal in terms of compression rate but local recovery of even one bit requires us to decompress the entire codeword. Let us define the local decodability of a compression scheme to be the minimum number of codeword bits that need to be read in order to recover a single bit of the message/raw data. Similarly, let the update efficiency be the minimum number of codeword bits that need to be modified in order to update a single message bit. For a space efficient (entropy-achieving) compression scheme, what is the smallest local decodability and update efficiency that we can achieve? Can we simultaneously achieve small local decodability and update efficiency, or is there a tradeoff between the two? All this, and more (including a new compression algorithm) will be discussed in the talk.

Contact(s) :

Ciblat Philippe

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