Multiple-Pass Decision-Directed Channel Estimation for Highly Mobile MIMO Communications

In multiple-input multiple-output (MIMO) wireless communication systems employing coherent detection, good performance depends on the availability of accurate channel estimates. This is a significant challenge in mobile MIMO systems where the channel coefficients change too rapidly for the effective use of traditional training methods. In this paper, we present a multiple-pass decision-directed scheme for channel estimation and symbol decoding in scenarios for which the MIMO channel varies rapidly. In this scheme, pilot symbols are embedded over a block of data symbols at the transmitter, and the receiver uses this pilot information to iteratively optimize the channel and symbol estimates over the entire symbol block. The optimization is carried out over a posterior distribution which incorporates information about the channel model and noise properties. The conjugate gradient algorithm is used to jointly optimize the channel estimates over the block. Simulations show the benefits of using embedded training and demonstrate the utility of this multiple-pass method

[1]  K. J. Ray Liu,et al.  Performance analysis for pilot-embedded data-bearing approach in space-time coded MIMO systems , 2005, Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005..

[2]  Alister G. Burr,et al.  Iterative channel estimation for turbo equalization over MIMO double selective fading channels , 2004, IEEE 60th Vehicular Technology Conference, 2004. VTC2004-Fall. 2004.

[3]  Albert Tarantola,et al.  Inverse problem theory - and methods for model parameter estimation , 2004 .

[4]  Ronald A. Iltis,et al.  Data detection and soft-Kalman filter based semi-blind channel estimation algorithms for MIMO-OFDM systems , 2005, IEEE International Conference on Communications, 2005. ICC 2005. 2005.

[5]  Ananthram Swami,et al.  Improved channel estimation using superimposed training , 2004, IEEE 5th Workshop on Signal Processing Advances in Wireless Communications, 2004..

[6]  A. Ranheim.  A decoupled approach to adaptive signal separation using an antenna array , 1999 .

[7]  A. Paulraj,et al.  Blind estimation of multiple co-channel digital signals using an antenna array , 1994, IEEE Signal Processing Letters.

[8]  A. Lee Swindlehurst,et al.  Analysis of a decision directed beamformer , 1995, IEEE Trans. Signal Process..

[9]  Magnus Sandell,et al.  Iterative channel estimation with MIMO MMSE-turbo equalisation , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[10]  Haidong Zhu,et al.  Pilot embedding for joint channel estimation and data detection in MIMO communication systems , 2003, IEEE Communications Letters.

[11]  Richard D. Wesel,et al.  Multi-input multi-output fading channel tracking and equalization using Kalman estimation , 2002, IEEE Trans. Signal Process..

[12]  He Zishu,et al.  MIMO channel tracking based on Kalman filter and MMSE-DFE , 2005, Proceedings. 2005 International Conference on Communications, Circuits and Systems, 2005..

[13]  Fredrik Tufvesson,et al.  Channel estimation with superimposed pilot sequence , 1999, Seamless Interconnection for Universal Services. Global Telecommunications Conference. GLOBECOM'99. (Cat. No.99CH37042).