Article

Design of Low-Density Parity-Check Codes for Modulation and Detection

Bell Labs., Crawford, NJ, USA
IEEE Transactions on Communications (Impact Factor: 1.99). 05/2004; 52(4):670 - 678. DOI: 10.1109/TCOMM.2004.826370
Source: IEEE Xplore

ABSTRACT

A coding and modulation technique is studied where the coded bits of an irregular low-density parity-check (LDPC) code are passed directly to a modulator. At the receiver, the variable nodes of the LDPC decoder graph are connected to detector nodes, and iterative decoding is accomplished by viewing the variable and detector nodes as one decoder. The code is optimized by performing a curve fitting on extrinsic information transfer charts. Design examples are given for additive white Gaussian noise channels, as well as multiple-input, multiple-output (MIMO) fading channels where the receiver, but not the transmitter, knows the channel. For the MIMO channels, the technique operates within 1.25 dB of capacity for various antenna configurations, and thereby outperforms a scheme employing a parallel concatenated (turbo) code by wide margins when there are more transmit than receive antennas.

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Available from: Alexei Ashikhmin, Dec 05, 2014
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    • "An equivalent model called herein the " virtual " channel is given by [12] y = Σ H Σ G V h G x + n, (3) where Σ H and Σ G are diagonal matrices containing the singular values of H, G, respectively and V G is the matrix of the right singular vectors of G. When LDPC is employed in this MIMO system, the overall utilization in b/s/Hz is determined by the mutual information between the transmitting branches x and the receiving ones, y [6], [7]. It is shown [12] that the mutual information between x and y, I(x; y), is only a function of W "
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    • "In this work, we analytically study the criterion for matching 44 the source statistics with source coding rate using an innovative 45 PEXIT chart technique. EXIT chart [11] is an accurate and con-46 venient tool for predicting the performance of LDPC codes. It 47 was introduced into D-LDPC code systems in [1] and extended 48 to P-LDPC codes in [12] as PEXIT chart. "

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    • "In this work, we analytically study the criterion for matching 44 the source statistics with source coding rate using an innovative 45 PEXIT chart technique. EXIT chart [11] is an accurate and con-46 venient tool for predicting the performance of LDPC codes. It 47 was introduced into D-LDPC code systems in [1] and extended 48 to P-LDPC codes in [12] as PEXIT chart. "
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