A linear criterion to optimize irregular LDPC codes for OFDM communications

This paper deals with optimized channel coding for OFDM transmissions (COFDM) over frequency selective channels using irregular low-density parity-check codes. Firstly, we introduce a new characterization of the LDPC code irregularity called "irregularity profile". Then, using this parameterization, we optimize the LDPC codes using the criterion based on the minimization of the convergence threshold. The optimization of this criterion is done using the Gaussian approximation technique. Simulations illustrate the good performance of our approach for different transmission channels.