J4 ›› 2011, Vol. 38 ›› Issue (2): 42-46.doi: 10.3969/j.issn.1001-2400.2011.02.008

• Original Articles • Previous Articles     Next Articles

Low complexity iterative demapping algorithm in BICM systems

MA Zhuo;DU Shuanyi;WANG Xinmei   

  1. (State Key Lab. of Integrated Service Networks, Xidian Univ., Xi'an  710071, China)
  • Received:2010-03-24 Online:2011-04-20 Published:2011-05-26
  • Contact: MA Zhuo E-mail:zma@mail.xidian.edu.cn

Abstract:

The complexity of the iterative Demapping algorithm in Bit-Interleaved Coded Modulation systems is related to the product of the order of modulation and the constellation points number, so that it is not suitable for real-time applications. To reduce its complexity, we give a shortcut calculation based on the Hard Decision Feedback for the BICM system using LDPC codes. A soft information calculation algorithm based on the decision boundary is used in the first iteration, where no feedback information is available to be used. Simulation result shows that the BWE performance of the algorithm proposed in the AWGN channel has only a distance of 0.04~0.06dB from the soft information iteration algorithm. On the other hand, the calculation complexity of this algorithm is only related to the order of the modulation, which is more suitable for application.

Key words: bit-interleaved coded modulation, iterative demapping, decision feedback, channel coding, low density parity-check code