Optimal Beamforming for Gaussian MIMO Wiretap Channels with Two Transmit Antennas

Mojtaba Vaezi, Wonjae Shin, H. Vincent Poor

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


A Gaussian multiple-input multiple-output wiretap channel in which the eavesdropper and legitimate receiver are equipped with arbitrary numbers of antennas and the transmitter has two antennas is studied in this paper. The input covariance matrix that achieves the secrecy capacity is determined. In particular, it is shown that the secrecy capacity of this channel can be achieved by linear precoding. Precoding and power allocation schemes that maximize the achievable secrecy rate, and thus achieve the secrecy capacity, are developed. The secrecy capacity is then compared with the achievable secrecy rate of generalized singular value decomposition (GSVD)-based precoding, which is the best previously proposed technique for this problem. Numerical results demonstrate that substantial gain can be obtained in secrecy rate between the proposed and GSVD-based precodings.

Original languageEnglish (US)
Article number7990372
Pages (from-to)6726-6735
Number of pages10
JournalIEEE Transactions on Wireless Communications
Issue number10
StatePublished - Oct 2017

All Science Journal Classification (ASJC) codes

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


  • MIMO wiretap channel
  • Physical layer security
  • beamforming
  • linear precoding
  • secrecy rate


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