Iterative Decoding,申请号US20090637868-传众专利搜索

Iterative Decoding

申请公布号：US2010091914(A1)

申请号：US20090637868

申请日期：2009.12.15

申请公布日期：2010.04.15

申请人：

TURIN WILLIAM

发明人：TURIN WILLIAM

分类号：H04L27/00;H04L1/00;H04L5/12;H04L27/06

主分类号：H04L27/00

摘要：This invention provides an iterative process to maximum a posteriori (MAP) decoding. The iterative process uses an auxiliary function which is defined in terms of a complete data probability distribution. The auxiliary function is derived based on an expectation maximization (EM) algorithm. For a special case of trellis coded modulators, the auxiliary function may be iteratively evaluated by a combination of forward-backward and Viterbi algorithms. The iterative process converges monotonically and thus improves the performance of any decoding algorithm. The MAP decoding minimizes a probability of error. A direct approach to achieve this minimization results in complexity which grows exponentially with T, where T is the size of the input. The iterative process avoids this complexity by converging on the MAP solution through repeated maximization of the auxiliary function.