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  • Research Article
  • Open Access

Optimal Multiuser Zero Forcing with Per-Antenna Power Constraints for Network MIMO Coordination

EURASIP Journal on Wireless Communications and Networking20112011:190461

  • Received: 31 October 2010
  • Accepted: 12 February 2011
  • Published:


We consider a multicell multiple-input multiple-output (MIMO) coordinated downlink transmission, also known as network MIMO, under per-antenna power constraints. We investigate a simple multiuser zero-forcing (ZF) linear precoding technique known as block diagonalization (BD) for network MIMO. The optimal form of BD with per-antenna power constraints is proposed. It involves a novel approach of optimizing the precoding matrices over the entire null space of other users' transmissions. An iterative gradient descent method is derived by solving the dual of the throughput maximization problem, which finds the optimal precoding matrices globally and efficiently. The comprehensive simulations illustrate several network MIMO coordination advantages when the optimal BD scheme is used. Its achievable throughput is compared with the capacity region obtained through the recently established duality concept under per-antenna power constraints.


  • Throughput Maximization
  • Gradient Descent Method
  • Zero Force
  • Achievable Throughput
  • Downlink Transmission

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Authors’ Affiliations

Electrical & Computer Engineeering, University of Alberta, and TRLabs, Edmonton, AB, Canada, T6G 2V4


© Saeed Kaviani and Witold A. Krzymień. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.