Skip to content


  • Research Article
  • Open Access

Realization of a Spatially Multiplexed MIMO System

  • 1,
  • 1,
  • 1 and
  • 1
EURASIP Journal on Advances in Signal Processing20062006:078349

  • Received: 14 December 2004
  • Accepted: 5 April 2005
  • Published:


Multi-antenna systems can provide improvements in wireless systems increasing spectral efficiency, reliability, range, and system capacity. Herein we show how some of the potentials of MIMO systems can be realized on a simple radio hardware platform by utilizing advanced real-time signal processing and coding. We present a real-time implementation of a 2 by 2 MIMO system employing spatial multiplexing to achieve high spectral efficiency in an indoor non-line-of-sight environment operating in the 1800 MHz range. Well-known processing and coding techniques are employed and our contributions lie in: discussing implementational aspects and solutions often overlooked but critical for high-performance operation; demonstrating the degree to which the simple baseband AWGN model can be used to accurately model/predict the MIMO system on the current hardware; and demonstrating the feasibility of real-time spatial multiplexing achieving up to 15 bps/Hz on a 2 by 2 system in a realistic indoor environment with off-the-shelf radio hardware.


  • Spectral Efficiency
  • MIMO System
  • Hardware Platform
  • Code Technique
  • Spatial Multiplex

Authors’ Affiliations

Department of Signals, Sensors, and Systems, Royal Institute of Technology (KTH), Stockholm, 100 44, Sweden


  1. Foschini GJ, Gans MJ: On limits of wireless communications in a fading environmen when using multiple antennas. Wireless Personal Communications 1998, 6(3):311–335. 10.1023/A:1008889222784View ArticleGoogle Scholar
  2. Telatar IE: Capacity of multi-antenna Gaussian channels. European Transactions on Telecommunications 1999, 10(6):585–595. 10.1002/ett.4460100604MathSciNetView ArticleGoogle Scholar
  3. Zheng L, Tse DNC: Diversity and multiplexing: a fundamental tradeoff in multiple-antenna channels. IEEE Transactions on Information Theory 2003, 49(5):1073–1096. 10.1109/TIT.2003.810646View ArticleGoogle Scholar
  4. Raleigh GG, Cioffi JM: Spatio-temporal coding for wireless communication. IEEE Transactions on Communications 1998, 46(3):357–366. 10.1109/26.662641View ArticleGoogle Scholar
  5. Foschini GJ: Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas. In Tech. Rep.. Lucent Technologies, Murray Hill, NJ, USA; 1996.Google Scholar
  6. Wolniansky PW, Foschini CJ, Golden GD, Valenzuela RA: V-BLAST: an architecture for realizing very high data rates over the rich-scattering wireless channel. Proceedings of URSI International Symposium on Signals, Systems, and Electronics (ISSSE '98), September–October 1998, Pisa, Italy 295–300.Google Scholar
  7. Horseman T, Webber J, Abdul-Aziz MK, et al.: A software and hardware evaluation of revolutionary turbo MIMO OFDM schemes for 5 GHz WLANs. Proceedings of 57th IEEE Semiannual Vehicular Technology Conference (VTC '03), April 2003, Jeju, Korea 4: 2788–2792.Google Scholar
  8. Sampath H, Talwar S, Tellado J, Erceg V, Paulraj A: A fourth-generation MIMO-OFDM broadband wireless system: design, performance, and field trial results. IEEE Communications Magazine 2002, 40(9):143–149. 10.1109/MCOM.2002.1031841View ArticleGoogle Scholar
  9. Zetterberg P: WIreless DEvelopment LABoratory (WIDELAB) equipment base. In Tech. Rep. S3-SB-0316. Department of Signals, Sensors and Systems, Royal Institute of Technology (KTH), Stockholm, Sweden; August 2003.Google Scholar
  10. Ungerboeck G: Trellis-coded modulation with redundant signal sets Part I: Introduction. IEEE Communications Magazine 1987, 25(2):5–11.View ArticleGoogle Scholar
  11. Ungerboeck G: Trellis-coded modulation with redundant signal sets Part II: State of the art. IEEE Communications Magazine 1987, 25(2):12–21.View ArticleGoogle Scholar
  12. Moose PH: A technique for orthogonal frequency division multiplexing frequency offset correction. IEEE Transactions on Communications 1994, 42(10):2908–2914. 10.1109/26.328961View ArticleGoogle Scholar
  13. Fanfoni S, Giancola D, Girola U, Parolari S, Picciriello A, Spagnolini U: Space-time processing for co-channel interference rejection and channel estimation in GSM/DCS systems. Proceedings of URSI International Symposium on Signals, Systems, and Electronics (ISSSE '98), September–October 1998, Pisa, Italy 152–155.Google Scholar
  14. Björck Å: Numerical Methods for Least Squares Problems. SIAM, Philadelphia, Pa, USA; 1996.View ArticleGoogle Scholar
  15. Neumaier A: Solving ill-conditioned and singular linear systems: a tutorial on regularization. SIAM Review 1998, 40(3):636–666. 10.1137/S0036144597321909MathSciNetView ArticleGoogle Scholar
  16. Agrawal D, Richardson TJ, Urbanke R: Multiple-antenna signal constellations for fading channels. IEEE Transactions on Information Theory 2001, 47(9):2618–2626.MathSciNetView ArticleGoogle Scholar
  17. Cioffi J: EE379 Class Reader. Stanford University, Stanford, Calif, USA; 1998.Google Scholar


© David Samuelsson et al. 2006

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.