Optimization of Nonlinear Signal Constellations for Real-World MIMO Channels

Bruno Clerckx, Luc Vandendorpe, Danielle Vanhoenacker-Janvier, Claude Oestges

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


The performance of spatial multiplexing (SM) multiple-input multiple-output (MIMO) communication systems is highly dependent on the richness of scattering, the presence of dominant components, and the interelement spacings. In this paper, a new interpretation of the impact of transmit correlation on the performance of SM is given based on a so-called "symbol-related array factor." Nonlinear signal constellations for SM over real-world fading channels are then designed by minimizing an estimate of the average symbol error rate under an average transmit power constraint. The new transmission scheme exploits the spectral efficiency advantage of SM and the robustness of eigen-beamforming. Through simulations, it is shown to be more robust against fading correlations and high Ricean K-factors than SM using the classical phase shift keying (PSK) and quadrature amplitude modulation (QAM) constellations. The symbol error rate performance of this scheme is not affected by a change in the propagation environment or the interelement distance. Furthermore, if the scheme is used on the uplink, no explicit rate-consuming feedback link from the base station to the mobile station is required.

Original languageEnglish
Pages (from-to)894-902
Number of pages9
JournalIEEE Transactions on Signal Processing
Issue number4
Publication statusPublished - 2004 Apr

Bibliographical note

Funding Information:
Manuscript received December 12, 2002; revised April 17, 2003. The work of B. Clerckx and C. Oestges was supported by the Belgian Fund FRIA and the Belgian NSF, respectively. The associate editor coordinating the review of this paper and approving it for publication was Dr. Rick S. Blum.


  • Beamforming
  • Correlated channels
  • Multiple-input multiple-output (MIMO)
  • Space-time coding
  • Spatial multiplexing

ASJC Scopus subject areas

  • Signal Processing
  • Electrical and Electronic Engineering


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