Optimal Lossless Source Codes for Timely Updates

Mayekar, Prathamesh and Parag, Parimal and Tyagi, Himanshu (2018) Optimal Lossless Source Codes for Timely Updates. In: IEEE International Symposium on Information Theory (ISIT), JUN 17-22, 2018, Vail, CO, pp. 1246-1250.

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Abstract

A transmitter observing a sequence of independent and identically distributed random variables seeks to keep a receiver updated about its latest observations. The receiver need not be apprised about each symbol seen by the transmitter, but needs to output a symbol at each time instant t. If at time t the receiver outputs the symbol seen by the transmitter at time U(t) <= t, the age of information at the receiver at time t is t - U(t). We study the design of lossless source codes that enable transmission with minimum average age at the receiver. We show that the asymptotic minimum average age can be attained (up to a constant bits gap) by Shannon codes for a tilted version of the original pmf generating the symbols, which can be computed easily by solving an optimization problem. Underlying our construction for minimum average age codes is a new variational formula for integer moments of random variables, which may be of independent interest.

Item Type:	Conference Proceedings
Series.:	IEEE International Symposium on Information Theory
Publisher:	IEEE
Additional Information:	Copy right for this article belong to IEEE
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	24 Nov 2018 14:29
Last Modified:	24 Nov 2018 14:29
URI:	http://eprints.iisc.ac.in/id/eprint/61134

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