Reconfigurable Low Density Parity Check (LDPC) Code Interleaving for SIO and MIMO OFDM Systems

This contribution derives an algorithm for optimizing the mapping of irregular and systematic low density parity check (LDPC) code word bits onto orthogonal frequency division multiplexing (OFDM) carriers in the context of a frequency selective fading channel in both, a single-transmit single-receive (SISO channel) and multiple-transmit multiple-receive (MIMO channel) antennas scenario. The absolute values of the frequency domain channel coefficients are assumed to be known and the LDPC code to be given (contrary to existing proposals where the LDPC code is optimized with respect to a given propagation channel). The proposed solution can alternatively be interpreted as an adaptive interleaver (which is inherently available in software defined radio type of system implementations) optimized for a given channel impulse response. In a typical WLAN (IEEE802.11n) scenario, the proposed mapping technique improves the system performance by up to approx. 0.7 dB compared to a linear (direct) mapping

[1]  Robert G. Gallager,et al.  Low-density parity-check codes , 1962, IRE Trans. Inf. Theory.

[2]  Leonard J. Cimini,et al.  Analysis and Simulation of a Digital Mobile Channel Using Orthogonal Frequency Division Multiplexing , 1985, IEEE Trans. Commun..

[3]  Radford M. Neal,et al.  Near Shannon limit performance of low density parity check codes , 1996 .

[4]  Joachim Hagenauer,et al.  Iterative decoding of binary block and convolutional codes , 1996, IEEE Trans. Inf. Theory.

[5]  Daniel A. Spielman,et al.  Analysis of low density codes and improved designs using irregular graphs , 1998, STOC '98.

[6]  Ali N. Akansu,et al.  Orthogonal transmultiplexers in communication: a review , 1998, IEEE Trans. Signal Process..

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

[8]  Sae-Young Chung,et al.  Analysis of sum-product decoding of low-density parity-check codes using a Gaussian approximation , 2001, IEEE Trans. Inf. Theory.

[9]  Sae-Young Chung,et al.  On the design of low-density parity-check codes within 0.0045 dB of the Shannon limit , 2001, IEEE Communications Letters.

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

[11]  Preben E. Mogensen,et al.  A stochastic MIMO radio channel model with experimental validation , 2002, IEEE J. Sel. Areas Commun..

[12]  David Declercq,et al.  Optimized Irregular Low-Density Parity-Check Codes for Multicarrier Modulations over Frequency-Selective Channels , 2004, EURASIP J. Adv. Signal Process..