Constrained Channel Coding Using a Reduced Number of Arithmetic String Coding Steps Per Cycle
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
This invention relates to the expansion of the bit strings from the Markov binary source into longer strings characteristic of a (d,k) constrained channel code using an arithmetic string decoder having a selected shift and add to event decoding operation. A (d,k) code is described by a (k+1) state finite state machine (FSM), with states 0,1,...,k. Binary alternatives (flux reversal or no flux reversal) occur at states d,d+1,...,k-1. In these states channel information is conveyed. Corresponding to each of these states is a Shannon probability for each alternative which maximizes the information-carrying capacity of the constrained channel. A binary arithmetic code can be used for approximating probabilities in this range.