Patent ID: 7447280

Claim:
A method executed in a receiver for maximum a posteriori (MAP) decoding of an input information sequence, X, that includes steps of receiving a signal, forming a received sequence Y, decoding the received sequence, and outputting a decoded result, where the decoding is characterized by: iteratively maximizing an auxiliary function that includes a product of elements p ij (XY) of a probability distribution matrix P(X,Y) where the input information signal travels through a channel represented by a Hidden Markov Model (HMM) to reach said receiver, and said auxiliary function is proportionally related to ∏ t = 1 T ⁢ p t - 1 , i ⁡ ( X t , Y t ) ⁢ ⁢ where ⁢ ⁢ p ij ⁡ ( X , Y ) = Pr ⁡ ( j , X , Y | i ) , are conditional probability density functions of an information element X of information sequence X that corresponds to a received element Y of sequence Y after the HMM transfers from a state i to a state j.