Optimal Variable Length Codes (Arbitrary Symbol Cost and Equal Code Word Probability)

The problem of constructing minimum-redundancy prefix codes for the general discrete noiseless channel without constraints is solved for unequal code letter costs, provided that the symbols encoded are assumed to be equally probable. A graphical technique is developed for solving the problem for which the code words are equally probable and are constructed from r symbols where r is greater than or equal to two. A method is given for constructing an optimal exhaustive prefix code. This method is then generalized to the extent that the exhaustive constraint is deleted, thereby resulting in an algorithm, designated ACE for arbitrary symbol cost and equal code word probability, which solves the stated problem. Abstract © Elsevie