An FPGA Implementation of an MML-DFE for Spatially Multiplexed MIMO Systems

공간다중화 MIMO 시스템을 위한 MML-DFE기법의 FPGA 구현

  • 임태호 (중앙대학교 전자전기공학부 디지털통신연구실) ;
  • 이규인 (중앙대학교 전자전기공학부 디지털통신연구실) ;
  • 박창환 (중앙대학교 전자전기공학부 디지털통신연구실) ;
  • 정기철 (중앙대학교 전자전기공학부 디지털통신연구실) ;
  • 유성욱 (중앙대학교 전자전기공학부 디지털통신연구실) ;
  • 김재권 (연세대학교 원주캠퍼스 컴퓨터정보통신공학부) ;
  • 조용수 (중앙대학교 전자전기공학부 디지털통신연구실)
  • Published : 2006.11.30

Abstract

The ML-DFE(Maximum Likelihood-Decision Feedback Equalization) can be viewed as either a suboptimal signal detection method for reducing hardware complexity of ML or an enhanced detection method for reducing the effect of error propagation of SIC(Successive Interference Cancellation) in spatially multiplexed MIMO systems such as V-BLAST. The ML-DFE can achieve a higher diversity in rich scattering environments as well as reducing the error propagation effect by combing ML decoding with the DFE. In this paper, an MML-DFE(Modified Maximum Likelihood-Decision Feedback Equalization) is proposed to reduce the hardware complexity of the ML-DFE, without compromising performance. It is shown by FPGA implementation that the proposed MML-DFE can achieve the same performance as the ML-DFE with significantly reduced hardware complexity.

ML-DFE(Maximum Likelihood-Decision Feedback Equalization) 기법은 V-BLAST와 같은 공간다중화 MIMO시스템에서 ML 기법의 구현 복잡도를 줄이기 위한 준 최적 신호검출기법으로 불 수 있다. ML-DFE 기법은 ML 기법과 DFE 기법을 결합하여 오차전파를 줄이면서 rich scattering 환경에서 높은 다이버시티 이득을 얻을 수 있다. 본 논문에서는 ML-DFE 기법과 동일한 성능을 보이면서 연산복잡도를 줄일 수 있는 MML-DFE(Modified Maximum Likelihood - Decision Feedback Equalization) 기법을 제안한다. 또한 FPGA 구현을 통하여 제안된 MML-DFE 기법이 기존 ML-DFE 기법에 비하여 구현복잡도를 크게 감소시키면서 동일한 성능을 유지함을 확인한다.

Keywords

References

  1. A. F. Naguib, N. Seshadri, and A. R. Calderbank, 'Increasing data rate over wireless channel,' IEEE Signal Process. Mag., vol. 17, no. 2, pp. 744-765, Mar. 1998
  2. V. Tarokh, H. jafarkhani, and A. R. Calderbank, 'Space-Time block codes from orthogonal design,' IEEE Trans. Inf. Theory, vol. 45, no. 5, pp. 1456-1467, July 1999 https://doi.org/10.1109/18.771146
  3. D. Shiu and J. M. Kahn, 'Layered space-time codes for wireless communications using multiple transmit antennas,' in Proc. IEEE ICC, pp. 436-440, June 1999
  4. P. W. Wolniansky, G. J. Foschini, G. D. Golden, and R. A. Valenzuela, 'V-BLAST: an architecture for realizing very high data rates over the rich-scattering wireless channel,' in Proc. URSI ISSSE pp. 295-300, Sept. 1998
  5. G. J. Foschini, G. D. Golden, R. A. Valenzuela, and P. W. Wolniansky, 'Simplified processing for high spectral efficiency wirelss communications employing multi-element arrays,' IEEE J. Sel, Areas Commun., vol. 17, pp. 1841-1852, Nov. 1999 https://doi.org/10.1109/49.806815
  6. T. Haustein, A. Forck, H. Gabler, V. Jungnickel, and S. Schiffennuller, 'Real-time signal processing for multiantenna systems: algorithms, optimization, and implementation on an experimental rtest-bed,' EURASIP Journal on Applied Signal Processing, vol.2006, pp.1-21, 2006
  7. W. Wubben, R. Behnke, J. Rinas, V. Kuhn, and K. D. Kammever, 'Efficient algorithm for decoding layered space-time codes,' lEE Electron. Lett., vol. 37, pp. 1348-1350, Oct. 2001 https://doi.org/10.1049/el:20010899
  8. O. M. Darmen, H. E. Garnal, and G. Caire, 'On the complexity of ML detection and the search for the closest lattice point,' IEEE Transactions on Information Theory, vol. 59, no. 10, pp.2400-2414, Oct. 2003
  9. H. Kawai, K. Higuichi, N. Maeda, M. Sawahashi, T. Ito, Y. Kakura, A. Ushirokawa, and H. Seki, 'Likelihood Function for QRM-MLD suitable for soft-decision turbo decoding and its performance for OFCDM MIMO multiplexing in multipath fading channel,' lElCE Trans. Commun., vol. E88-B, no. 1,pp. 47-57, Jan. 2005
  10. W. Choi, R. Negi, and J. M. Cioffi, 'Combined ML and DFE decoding for the V-BLAST system,' in Proc. IEEE ICC, pp. 1243-1248, June 2000