Capacity of cognitive interference channels with and without secrecy

Yingbin Liang, Anelia Somekh-Baruch, H. Vincent Poor, Shlomo Shamai, Sergio Verdú

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139 Scopus citations


Like the conventional two-user interference channel, the cognitive interference channel consists of two transmitters whose signals interfere at two receivers. It is assumed that there is a common message (message 1) known to both transmitters, and an additional independent message (message 2) known only to the cognitive transmitter (transmitter 2). The cognitive receiver (receiver 2) needs to decode messages 1 and 2, while the noncognitive receiver (receiver 1) should decode only message 1. Furthermore, message 2 is assumed to be a confidential message which needs to be kept as secret as possible from receiver 1, which is viewed as an eavesdropper with regard to message 2. The level of secrecy is measured by the equivocation rate. In this paper, a single-letter expression for the capacity-equivocation region of the discrete memoryless cognitive interference channel is obtained. The capacity-equivocation region for the Gaussian cognitive interference channel is also obtained explicitly. Moreover, particularizing the capacity-equivocation region to the case without a secrecy constraint, the capacity region for the two-user cognitive interference channel is obtained, by providing a converse theorem.

Original languageEnglish
Pages (from-to)604-619
Number of pages16
JournalIEEE Transactions on Information Theory
Issue number2
StatePublished - 2009
Externally publishedYes

Bibliographical note

Funding Information:
Manuscript received December 18, 2007; revised September 30, 2008. Current version published February 04, 2009. The material in this paper was presented in part at the 45th Annual Allerton Conference on Communication, Control, and Computing, Monticello, IL, September 2007. The work of Y. Liang and H. V. Poor was supported by the National Science Foundation under Grants ANI-03-38807, CNS-06-25637, and CCF-07-28208. The work of A. Somekh-Baruch was supported by a Marie Curie Outgoing International Fellowship within the 6th European Community Framework Programme. The work of S. Shamai and S. Verdú was supported by the US–Israel Binational Science Foundation. The work of S. Verdú was also supported by the National Science Foundation under Grant CCF-0635154.

Funding Information:
Dr. Somekh-Baruch received the Tel-Aviv University program for outstanding B.Sc. students scholarship, the Viterbi scholarship, the Rothschild foundation scholarship for postdoctoral studies, and the Marie Curie Outgoing International Fellowship.


  • Capacity-equivocation region
  • Cognitive communication
  • Confidential messages
  • Interference channel
  • Rate splitting
  • Secrecy capacity region


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