The MIMO wiretap channel decomposed

Anatoly Khina, Yuval Kochman, Ashish Khisti

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The problem of sending a secret message over the Gaussian multiple-input multiple-output (MIMO) wiretap channel is studied. While the capacity of this channel is known, it is not clear how to construct optimal coding schemes that achieve this capacity. In this paper, we use linear operations along with successive interference cancellation to attain effective parallel single-antenna wiretap channels. By using independent scalar Gaussian wiretap codebooks over the resulting parallel channels, the capacity of the MIMO wiretap channel is achieved. The derivation of the schemes is based upon joint triangularization of the channel matrices. We find that the same technique can be used to rederive capacity expressions for the MIMO wiretap channel in a way that is simple and closely connected to a transmission scheme. This technique allows to extend the previously proven strong security for scalar Gaussian channels to the MIMO case. We further consider the problem of transmitting confidential messages over a two-user broadcast MIMO channel. For that problem, we find that derivation of both the capacity and a transmission scheme is a direct corollary of the proposed analysis for the MIMO wiretap channel.

Original languageAmerican English
Article number7937907
Pages (from-to)1046-1063
Number of pages18
JournalIEEE Transactions on Information Theory
Issue number2
StatePublished - Feb 2018

Bibliographical note

Publisher Copyright:
© 2017 IEEE.


  • Confidential broadcast
  • Dirty-paper coding
  • MIMO channel
  • Matrix decomposition
  • Successive interference cancellation
  • Wiretap channel


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