DOI QR코드

DOI QR Code

평균 제곱 투영 오차의 기울기에 기반한 가변 망각 인자 FAPI 알고리즘

Mean Square Projection Error Gradient-based Variable Forgetting Factor FAPI Algorithm

  • 서영광 (부산대학교 전자전기컴퓨터공학과) ;
  • 신종우 (부산대학교 전자전기컴퓨터공학과) ;
  • 서원기 ((주) 넥스윌) ;
  • 김형남 (부산대학교 전자전기컴퓨터공학과)
  • Seo, YoungKwang (Department of Electrical and Computer Engineering, Pusan National University) ;
  • Shin, Jong-Woo (Department of Electrical and Computer Engineering, Pusan National University) ;
  • Seo, Won-Gi (NEXTWILL Co., Ltd.) ;
  • Kim, Hyoung-Nam (Department of Electrical and Computer Engineering, Pusan National University)
  • 투고 : 2013.12.30
  • 심사 : 2014.04.30
  • 발행 : 2014.05.25

초록

본 논문에서는 고속 부공간 추적 기법인 FAPI (Fast Approsimated Power Iteration)에 GVFF RLS (Gradient-based Variable Forgetting Factor Recursive Least Square Error)를 적용한 GVFF FAPI 를 제안한다. 기존의 FAPI는 신호의 공분산 행렬을 추정하기 위해 고정 망각 인자를 사용하기에, 부공간이 지속적으로 변하는 비정재 환경에 적용하기 여려운 단점이 있다. 이러한 문제점을 해결하기 위해, GVFF FAPI는 개선된 MSE (Mean Square Error)의 분석으로부터 유도된 MSE의 기울기 기반의 시변 망각 인자를 사용한다. 또한 GVFF RLS의 망각 인자 업데이트 식을 개선하여 부공간이 지속적으로 변하는 비정재 환경에서 부공간 에러를 줄인다. 개선된 망각 인자 업데이트 식은 MSE의 기울기가 양수이면 망각 인자를 빠르게 감소하게 하고 MSE의 기울기가 음수이면 망각 인자를 천천히 증가시킨다. 모의실험을 통해서 도래각이 지속적으로 변하는 환경에서 GVFF FAPI 알고리즘이 기존의 FAPI 알고리즘보다 작은 부공간 에러를 가지는 것을 보이고, 추적된 부공간을 도래각 추정기법에 적용하였을 때 추적된 도래각의 RMSE (Root Mean Square Error)가 더 작은 것을 확인한다.

This paper proposes a fast subspace tracking methods, which is called GVFF FAPI, based on FAPI (Fast Approximated Power Iteration) method and GVFF RLS (Gradient-based Variable Forgetting Factor Recursive Lease Squares). Since the conventional FAPI uses a constant forgetting factor for estimating covariance matrix of source signals, it has difficulty in applying to non-stationary environments such as continuously changing DOAs of source signals. To overcome the drawback of conventioanl FAPI method, the GVFF FAPI uses the gradient-based variable forgetting factor derived from an improved means square error (MSE) analysis of RLS. In order to achieve the decreased subspace error in non-stationary environments, the GVFF-FAPI algorithm used an improved forgetting factor updating equation that can produce a fast decreasing forgetting factor when the gradient is positive and a slowly increasing forgetting factor when the gradient is negative. Our numerical simulations show that GVFF-FAPI algorithm offers lower subspace error and RMSE (Root Mean Square Error) of tracked DOAs of source signals than conventional FAPI based MUSIC (MUltiple SIgnal Classification).

키워드

참고문헌

  1. J. Landon, B.D. Jeffs, Karl F. Warnick, "Model-Based Subspace Projection Beamforming for Deep Interference Nulling," IEEE Trans, Signal Processing, vol 60, no 3, pp. 1215-1228, Mar. 2012. https://doi.org/10.1109/TSP.2011.2177825
  2. S. Dib, M. Barkat, M. Grimes, "PAST and OPAST algorithms for STAP in monostatic airborne radar," International Symposium on Innovations in Intelligent Systems and Applications, pp. 177-181, Jun. 2011.
  3. Pu Wang, Man-On Pun, Z. Sahinoglu, "Low-complexity stap via subspace tracking in compound-Gaussian environment," IEEE Radar Conference, pp. 356-361, May 2011.
  4. K. Kumatani, J. McDonough, B. Raj, "Maximum kurtosis beamforming with a subspace filter for distant speech recognition," IEEE Workshop on. Automatic Speech Recognition and Understanding, pp. 179-184, Dec. 2011.
  5. Christos G. Tsinos, Kostas Berberidis, "Blind Opportunistic Interference Alignment in MIMO Cognitive Radio Systems," IEEE Emerging and Selected Topics in Circuits and Systems, vol. 3, no. 4, pp. 626-639, Dec. 2013. https://doi.org/10.1109/JETCAS.2013.2284611
  6. Olutayo O. Oyerinde, Stanley H. Mneney, "Regularized Adaptive Algorithms-Based CIR Predictors for Time-Varying Channels in OFDM Systems," IEEE Signal Processing Letters, vol. 18, no. 9, pp. 505-508, Sep. 2011. https://doi.org/10.1109/LSP.2011.2160942
  7. P. Comon, G.H. Golub, "Tracking a few extreme singular values and vectors in signal processing," Proceedings of the IEEE, vol. 78, no. 8, Aug. 1990.
  8. B. Yang, "Projection Approximation Subspace Tracking," IEEE Trans. Signal Processing, vol. 43, no. 1, pp. 95-107, Jan. 1995. https://doi.org/10.1109/78.365290
  9. R. Badeau, B. David, and G. Richard, "Fast Approximated Power Iterations Subspace Tracking," IEEE Trans. Signal Processing, vol. 53, no. 9, pp. 2931-2941, Aug. 2005. https://doi.org/10.1109/TSP.2005.850378
  10. P.Strobach, "The fast recursive row-Householder subspace tracking algorithm," Signal Processing, vol. 89, no. 12, pp. 2514-2528, Dec, 2009. https://doi.org/10.1016/j.sigpro.2009.04.012
  11. Xenofon G. Doukopoulos, George V. Moustakides, "Fast and Stable Subspace Tracking," IEEE Trans. Signal Processing, vol. 56, no. 4, Apr. 2008.
  12. S. Bartelmaos and K. Abed-Meraim, "Principal and minor subspace tracking: Algorithms & stability analysis," in Proc. ICASSP, Toulouse, France, pp. 560-563, May 2006.
  13. Rong Wang, Minli Yao, Daoming Zhang, Hongxing Zou, "Stable and Orthonormal OJA Algorithm with low complexity," IEEE Signal Processing Letters, vol. 18, no. 4, pp. 211-214, Apr. 2011.
  14. Shu-Hong Leung and C.F. So, "Gradient-Based Variable Forgetting Factor RLS Algorithm in Time-Varying Environments," IEEE Trans. Signal Processing, vol. 53, no. 8, Aug. 2005.
  15. P. Strobach, "Low-rank adaptive filters," IEEE Trans. Signal Processing, vol. 44. no. 12, pp. 293-2947, Dec. 1996.
  16. S. Haykin, "Adaptive Filter Theory", Englewood Cliffs. NJ: Prentice Hall, 4th ed, 2002.
  17. B. Yang and J. F. Bohme, "Rotation based RLS algorithms: Unified derivations, numerical properties and parallel implementations," IEEE Trans. Signal Processing, vol. 40, no. 5, pp. 1151-1167, May 1992. https://doi.org/10.1109/78.134478
  18. R. Badeau, B. David, and G. Richard, "Approximated power iterations for fast subspace tracking," Signal Processing and Its Applications, 2003. Proceedings. Seventh International Symposium on, vol. 2, pp. 583-586, Jul. 2003.
  19. R.O. Schmidt, "Multiple emitter location and signal parameter estimation," IEEE Trans. AP, vol. 34, no. 3, pp. 276-280, Mar. 1986. https://doi.org/10.1109/TAP.1986.1143830
  20. R. Kumaresan and D.W. Tufts, "Estimating the angles of arrival of multiple plane waves," IEEE Trans. Aerosp. Elect. Systems, vol. AES-19, pp. 134-139, Jan. 1983. https://doi.org/10.1109/TAES.1983.309427
  21. Young-Kug Pyeon, Ki-Sung Kang, Sang-Heung Shim, Sang-Ok, Yoon, and Jun-Seok Lim "VFF-PASTd for Nonstationary DOA Estimation," IEIE, vol 41, no. 2, pp. 115-120, Jul. 2004.
  22. D. T. M. Slock, T. Kailath, "Fast transversal filters with data sequence weighting," IEEE Trans. Acoust., Speech, Signal Processing, vol. 33, no. 3, pp. 346-359, Mar. 1989.
  23. B. Toplis, S. Pasupathy, "Tracking Improvements in fast RLS algorithms using a variable forgetting factor," IEEE trans. Acoust., Speech, Signal Processing, vol. 36, no. 2, pp. 206-227, Feb. 1988. https://doi.org/10.1109/29.1514
  24. R.D. DeGroat, "Subspace Tracking," CRC Press LLC, 1999.