LDPC Codes Performance using MaxLog-MAP Algorithm for High Order Constellations

  IJETT-book-cover  International Journal of Recent Engineering Science (IJRES)          
© 2019 by IJRES Journal
Volume-6 Issue-3
Year of Publication : 2019
Authors : Latifa Mostari


MLA Style: Latifa Mostari "LDPC Codes Performance using MaxLog-MAP Algorithm for High Order Constellations" International Journal of Recent Engineering Science 6.3(2019):22-25. 

APA Style: Latifa Mostari, LDPC Codes Performance using MaxLog-MAP Algorithm for High Order Constellations. International Journal of Recent Engineering Science, 6(3),22-25.

The exact calculation, LLR (Log-Likelihood Ratio) or APP (A Posteriori Probability) of the QAM (Quadrature Amplitude Modulation) demapping involves complicated operations. Several algorithms have been introduced to simplify the calculation of the LLR, such as a pragmatic algorithm, Max-Log-MAP algorithm. In this work, we apply the Max-Log-MAP algorithm for binary LDPC codes. Simulation results show that the LDPC codes using the Max-Log-MAP algorithm for 16-QAM and 64-QAM constellations can achieve a good performance of binary LDPC codes with a simple calculation over Gaussian and Rayleigh channels.

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LDPC codes, LLR, Max-log-Map algorithm, Pragmatic algorithm, QAM mapping, Sum-Product Algorithm.