Opportunistic secrecy with a strict delay constraint

Karim Khalil, O. Ozan Koyluoglu, Hesham El Gamal, Moustafa Youssef

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


We investigate the delay limited secrecy capacity of the flat fading channel under two different assumptions on the available transmitter channel state information (CSI). The first scenario assumes perfect prior knowledge of both the main and eavesdropper channel gains. Here, upper and lower bounds on the delay limited secrecy capacity are derived, and shown to be tight in the high signal-to-noise ratio (SNR) regime. In the second scenario, only the main channel CSI is assumed to be available at the transmitter where, remarkably, we establish the achievability of a non-zero delay-limited secure rate, for a wide class of channel distributions, with a high probability. In the two cases, our achievability arguments are based on a novel two-stage key-sharing approach that overcomes the secrecy outage phenomenon observed in earlier works.

Original languageEnglish (US)
Article number6630484
Pages (from-to)4700-4709
Number of pages10
JournalIEEE Transactions on Communications
Issue number11
StatePublished - Nov 2013


  • Delay limited communication
  • Information theory
  • Physical layer security
  • Wiretap channel
  • key agreement

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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