MMSE based block diagonalization for cognitive radio MIMO broadcast channels

Kyoung Jae Lee, Inkyu Lee

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


In this paper, we present a linear precoder design for cognitive radio (CR) multi-user multiple-input multiple-output (MU-MIMO) downlink systems where unlicensed secondary users (SUs) can simultaneously utilize the same spectrum used by a licensed primary user (PU). Although a zero-forcing block diagonalization (ZF-BD) precoder is extended to the CR network with the PU, a transmit power boost problem occurs. Therefore, we propose a regularized BD precoder method based on the minimum mean-squared error (MMSE) criteria subject to the interference power constraint under a predetermined threshold for the PU. As a result, the proposed CR-MMSE-BD scheme improves the signal-to- interference-plus-noise ratio at each SU's receiver, compared to the ZF-BD based method. The simulation results demonstrate that the proposed algorithm outperforms the ZF based technique for CR MU-MIMO downlink systems.

Original languageEnglish
Article number6002431
Pages (from-to)3139-3144
Number of pages6
JournalIEEE Transactions on Wireless Communications
Issue number10
Publication statusPublished - 2011 Oct


  • Cognitive radio
  • block diagonalization (BD)
  • minimum mean-squared error (MMSE)
  • multi-user MIMO

ASJC Scopus subject areas

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


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