EXIT analysis of M-algorithm based MIMO detectors and LDPC code design optimization

This paper investigates joint design and optimization of both low density parity check (LDPC) codes and M-algorithm based detectors including iterative tree search (ITS) and soft-output M-algorithm (SOMA) in multiple-input multiple-output (MIMO) systems via the tool of extrinsic information transfer (EXIT) charts. First, we present EXIT analysis for ITS and SOMA. We indicate that the extrinsic information transfer curves of ITS obtained by Monte Carlo simulations based on output log-likelihood rations are not true EXIT curves, and the explanation for such a phenomenon is given, while for SOMA, the true EXIT curves can be computed, enabling the code design. Then, we propose a new design rule and method for LDPC code degree profile optimization in MIMO systems. The algorithm can make the EXIT curves of the inner decoder and outer decoder match each other properly, and can easily attain the desired code with the target rate. Also, it can transform the optimization problem into a linear one, which is computationally simple. The significance of the proposed optimization approach is validated by the simulation results that the optimized codes perform much better than standard non-optimized ones when used together with SOMA detector.

[1]  Yong Wang,et al.  A vision from the future: beyond 3G TDD , 2005, IEEE Commun. Mag..

[2]  Xiaohu You,et al.  The FuTURE Project in China , 2005, IEEE Commun. Mag..

[3]  Paul H. Siegel,et al.  Design of multi-input multi-output systems based on low-density Parity-check codes , 2005, IEEE Transactions on Communications.

[4]  Mathini Sellathurai,et al.  Turbo-MIMO for wireless communications , 2004, IEEE Communications Magazine.

[5]  Dharmendra S. Modha,et al.  Extended bit-filling and LDPC code design , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[6]  Zhi-Quan Luo,et al.  Soft quasi-maximum-likelihood detection for multiple-antenna wireless channels , 2003, IEEE Trans. Signal Process..

[7]  Bhaskar D. Rao,et al.  LDPC-coded MIMO systems with unknown block fading channels: soft MIMO detector design, channel estimation, and code optimization , 2006, IEEE Transactions on Signal Processing.

[8]  Stephan ten Brink,et al.  Extrinsic information transfer functions: model and erasure channel properties , 2004, IEEE Transactions on Information Theory.

[9]  Guosen Yue,et al.  Analysis and Design of Finite-Length LDPC Codes , 2007, IEEE Transactions on Vehicular Technology.

[10]  Zhang Ping,et al.  A Novel Low-Complexity Iterative Receiver for MIMO-BICM Systems , 2007 .

[11]  Stephan ten Brink,et al.  Convergence behavior of iteratively decoded parallel concatenated codes , 2001, IEEE Trans. Commun..

[12]  Rüdiger L. Urbanke,et al.  The capacity of low-density parity-check codes under message-passing decoding , 2001, IEEE Trans. Inf. Theory.

[13]  Guosen Yue,et al.  Performance analysis and design optimization of LDPC-coded MIMO OFDM systems , 2004, IEEE Trans. Signal Process..

[14]  Gianluigi Ferrari,et al.  Serial concatenation of LDPC codes and differential modulations , 2005, IEEE Journal on Selected Areas in Communications.

[15]  Tricia J. Willink,et al.  Iterative tree search detection for MIMO wireless systems , 2005, IEEE Transactions on Communications.

[16]  Stephan ten Brink,et al.  Achieving near-capacity on a multiple-antenna channel , 2003, IEEE Trans. Commun..

[17]  Peter J. McLane,et al.  Reduced-complexity equalization techniques for ISI and MIMO wireless channels in iterative decoding , 2008, IEEE Journal on Selected Areas in Communications.

[18]  K. Wong The soft-output m-algorithm and its applications , 2006 .

[19]  Joachim Hagenauer,et al.  The List-Sequential (LISS) Algorithm and Its Application , 2007, IEEE Transactions on Communications.

[20]  Stephan ten Brink,et al.  Design of low-density parity-check codes for modulation and detection , 2004, IEEE Transactions on Communications.

[21]  M. J. Gans,et al.  On Limits of Wireless Communications in a Fading Environment when Using Multiple Antennas , 1998, Wirel. Pers. Commun..

[22]  Rüdiger L. Urbanke,et al.  Design of capacity-approaching irregular low-density parity-check codes , 2001, IEEE Trans. Inf. Theory.

[23]  Stephen P. Boyd,et al.  Convex Optimization , 2004, Algorithms and Theory of Computation Handbook.