Patent ID: 6393072
Filing Date: 2002-05-21
Classification: H04L

Abstract:
A method for decoding received data organized into frames and which data is encoded by a finite-state data encoder for transmission over a data channel, said method comprising the steps of:procuring a table of joint statistics representing the probability of occurrence, in a frame, of each of the bits of the frame, for a representative set of source data, given that the corresponding bit in the adjacent frame has a particular logic level, and for the type of data encoder being used; calculating gamma in response to said received data and source statistics signals, to thereby produce gamma signals; generating, from said gamma signals, state probability signals and transition probability signals, said state probability signals representing the probability that said finite-state encoder was in a given state at the time at which the bit currently being evaluated was generated, and said transition probability signals representing the probability of traversing a given pair of states, where the two states are separated by one transition interval; processing said state probability and transition probability signals to produce bit probability signals indicative of the probability that said bit currently being evaluated is in a given logic level; and generating said source distribution signal in response to at least said bit probability signals and the values in said table of joint statistics; and using said source distribution signal as the source statistics signals in computing the said gamma values for decoding the subsequent frame of data.