New results on the capacity of the gaussian cognitive interference channel

Stefano Rini*, Daniela Tuninetti, Natasha Devroye

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

16 Scopus citations

Abstract

The capacity of the two-user Gaussian cognitive interference channel, a variation of the classical interference channel where one of the transmitters has knowledge of both messages, is known in several parameter regimes but remains unknown in general. In this paper, we consider the following achievable scheme: the cognitive transmitter pre-codes its message against the interference created at its intended receiver by the primary user, and the cognitive receiver only decodes its intended message, similar to the optimal scheme for "weak interference"; the primary decoder decodes both messages, similar to the optimal scheme for "very strong interference". Although the cognitive message is pre-coded against the primary message, by decoding it, the primary receiver obtains information about its own message, thereby improving its rate. We show: (1) that this proposed scheme achieves capacity in what we term the "primary decodes cognitive" regime, i.e., a subset of the "strong interference" regime that is not included in the "very strong interference" regime for which capacity was known; (2) that this scheme is within one bit/s/Hz and a factor two of capacity for a large set of parameters, thus improving the best known constant gap result; (3) we provide insights into the trade-off between interference pre-coding at the cognitive encoder and interference decoding at the primary receiver.

Original languageEnglish
Title of host publication2010 48th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2010
Pages637-644
Number of pages8
DOIs
StatePublished - 1 Dec 2010
Event48th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2010 - Monticello, IL, United States
Duration: 29 Sep 20101 Oct 2010

Publication series

Name2010 48th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2010

Conference

Conference48th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2010
CountryUnited States
CityMonticello, IL
Period29/09/101/10/10

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