Journal of Communications and Networks

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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Fixed-Complexity Sphere Encoder for Multi-User MIMO Systems

  • Mohaisen, Manar (Graduate School of Information Technology and Telecommunications, Inha University) ;
  • Chang, Kyung-Hi (Graduate School of Information Technology and Telecommunications, Inha University)
  • Received : 2009.09.18
  • Accepted : 2010.10.20
  • Published : 2011.02.28
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Abstract

In this paper, we propose a fixed-complexity sphere encoder (FSE) for multi-user multi-input multi-output (MU-MIMO) systems. The proposed FSE accomplishes a scalable tradeoff between performance and complexity. Also, because it has a parallel tree-search structure, the proposed encoder can be easily pipelined, leading to a tremendous reduction in the precoding latency. The complexity of the proposed encoder is also analyzed, and we propose two techniques that reduce it. Simulation and analytical results demonstrate that in a $4{\times}4$ MU-MIMO system, the proposed FSE requires only 11.5% of the computational complexity needed by the conventional QR decomposition with M-algorithm encoder (QRDM-E). Also, the encoding throughput of the proposed encoder is 7.5 times that of the QRDM-E with tolerable degradation in the BER performance, while achieving the optimum diversity order.

Keywords

References

  1. H. Weingarten: Y. Steinberg, and S. Shamai, "The capacity region of the Gaussian multlple-mput multiple.output broadcast channel," IEEE Trans. Inf. Theory, vol. 52, no. 9, pp. 3936-3964, Sept. 2006.
  2. M. Costa, "Writing on dirty paper," IEEE Trans. Inf. Theory, vol. 29, pp. 439-441, May 1983. https://doi.org/10.1109/TIT.1983.1056659
  3. C. Peel, B. Hochwald, and L. Swindlehurst, "A vector.perturbation tech. nique for near-capacity multiantenna multiuser communication - Part I: Channel inversion and regularization," IEEE Trans. Commun., vol. 53, no. 1, pp.195-202, Jan. 2005. https://doi.org/10.1109/TCOMM.2004.840638
  4. M. Tomlinson, "New automatic equalizer employing modulo arith. metic,"Electronics Letters, vol. 7, pp. 138-139, Mar. 1971. https://doi.org/10.1049/el:19710089
  5. H. Harashima and H. Miyakawa, "Matched.transmission technique for channels with intersymbol interference," IEEE Trans. Commun., vol. 20, no.4,pp. 774-780, Aug. 1972. https://doi.org/10.1109/TCOM.1972.1091221
  6. B. Hochwald, C. Peel, and L. Swindlehurst, "A vector-perturbation technique for near-capacity multiantenna multiuser communication - Part II: Perturbation," IEEE Trans. Commun., vol. 53, no. 3, pp. 537-544, Mar. 2005. https://doi.org/10.1109/TCOMM.2004.841997
  7. J. Z. Zhang and K. J. Kim, "Near-capacity MIMO multiuser precoding With QRD-M algorithm;' in Proc. IEEE ACSSC., Nov. 2005, pp. 1498- 1502.
  8. L. Barbero and J. Thompson, "Performance analysis of a fixed-complexity sphere decoder in high-dimensional MIMO systems," in Proc. IEEE ICASSP., May 2006, pp. 557-560.
  9. R. Habendorf and G. Fettweis. "On ordering optimization for MIMO systems with decentralized receivers," in Proc. IEEE VTC., May 2006, pp. 1844-1848.
  10. D. Wubben, R. Bohnke, V. Kuhn, and K.-D. Kammeyer, "MMSE extension of V-BLAST based on sorted QR decomposition," in Proc. IEEE VTC., Oct. 2003, pp. 508-512.
  11. L. Barbero and J. Thompson, "Rapid prototyping of the sphere decoder for MIMO systems" in Proc. lEE/EURASIP Conf. DSP enabled Radio, 2005.
  12. J. Liu and W. Krzymien, "Improved Tomlinson-Harashima precoding for the downlink for multi-user MIMO systems," Canadian J. Electr. Comput. Eng., vol. 32, no. 3, pp. 133-144, 2007.
  13. C. -B .. Chac, S. Shim, and R. Heath, Jr., "Block diagonalized vector perturbation for multiuser MIMO systems," IEEE Trans. Wireless Commun., vol. 7, no. 11, pp. 4051-4057, Nov. 2008.