On the secrecy degrees of freedom of the multiantenna block fading wiretap channels

Mari Kobayashi, Pablo Piantanida, Sheng Yang, Shlomo Shamai

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


We consider a practical scenario of the Gaussian multiantenna wiretap channel where a transmitter with no channel state information wishes to send a confidential message to its legitimate receiver in the presence of an eavesdropper. It has been known that the secrecy capacity of such a channel does not scale with signal-to-noise ratio under general conditions. Taking into account the different temporal fading structures at the legitimate receiver and the eavesdropper, we characterize lower and upper bounds on the secrecy degrees of freedom (s.d.o.f.) of the channel at hand. Our results show that a positive s.d.o.f. can be ensured whenever two receivers experience the asynchronous variation. Remarkably, simple linear precoding schemes provide the optimal s.d.o.f. in most cases of interest by aligning either the confidential signal at the eavesdropper or the artificial noise at the legitimate receiver.

Original languageEnglish
Article number5873149
Pages (from-to)703-711
Number of pages9
JournalIEEE Transactions on Information Forensics and Security
Issue number3 PART 1
StatePublished - Sep 2011
Externally publishedYes


  • Channel state information
  • information security
  • multiple antennas
  • time-varying channel


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