A new beamforming structure based on transmit-MRC for closed-loop MIMO systems

Seok Hwan Park, Heunchul Lee, Sang Rim Lee, Inkyu Lee

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


This paper proposes an efficient beamforming scheme which attains optimality as singular value decomposition (SVD) based systems with low complexity utilizing transmit maximum-ratio combining (TMRC) techniques. The TMRC scheme is the optimum structure for single beamforming systems in terms of received signal-to-noise ratio (SNR) in multiple-input single-output (MISO) channels. In this paper, we generalize the TMRC scheme to multiple beamforming multiple-input multipleoutput (MIMO) systems which support more than one data stream in coded systems. We express each beamforming vector as a linear combination of TMRC vectors whose coefficients are optimized in a successive manner. Optimization of the beamforming vector is followed by the decorrelation process. All TMRC vectors used as a basis of the remaining beamforming vectors are made orthogonal to previously computed beamforming vectors. Exploiting the concept of the gradient ascent algorithm, we propose a simple non-iterative method of computing the precoder which obtains the near optimal performance. Also we derive a closed form expression of the output SNR distribution for the proposed scheme. Simulation results demonstrate that the proposed scheme achieves the almost identical link performance as the SVD-based system for arbitrary configurations with reduced complexity.

Original languageEnglish
Pages (from-to)1847-1856
Number of pages10
JournalIEEE Transactions on Communications
Issue number6
Publication statusPublished - 2009


  • Closed-loop multiple-input multiple-output (MIMO) systems
  • Transmit beamforming

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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