Secrecy capacity of a class of orthogonal relay eavesdropper channels

Vaneet Aggarwal, Lalitha Sankar, A. Robert Calderbank, H. Vincent Poor

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Scopus citations


The secrecy capacity is developed for a class of relay channels with orthogonal components and a passive eavesdropper node. The relay and destination receive signals from the source on two orthogonal channels such that the destination also receives transmissions from the relay on its channel. The eavesdropper can overhear either one or both of the orthogonal channels. Inner and outer bounds on the secrecy capacity are developed for both the discrete memoryless and the Gaussian channel models. For the discrete memoryless case, the secrecy capacity is shown to be achieved by a partial decode-and-forward (PDF) scheme when the eavesdropper can overhear only one of the two orthogonal channels. Two new outer bounds are presented for the Gaussian model using recent capacity results for a Gaussian multi-antenna channel with a multi-antenna eavesdropper. The outer bounds are shown to be tight for two sub-classes of channels. The first sub-class is one in which the source and relay are clustered and the eavesdropper overhears on only one of the two channels for which the PDF strategy is optimal. The second is a sub-class in which the source does not transmit to the relay for which a noise-forwarding strategy is optimal.

Original languageEnglish (US)
Title of host publicationInformation Theory and Applications Workshop, ITA 2009
Number of pages6
StatePublished - 2009
EventInformation Theory and Applications Workshop, ITA 2009 - San Diego, CA, United States
Duration: Feb 8 2009Feb 13 2009

Publication series

NameInformation Theory and Applications Workshop, ITA 2009


OtherInformation Theory and Applications Workshop, ITA 2009
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • Computer Science Applications
  • Information Systems


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