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Probability Based Arithmetic Codes for (d,k) Channels

IP.com Disclosure Number: IPCOM000049963D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09

Publishing Venue

IBM

Related People

Authors:
Langdon, GG Todd, SJP [+details]

Abstract

This invention relates to a method for fixed rate channel coding which uses arithmetic coding. It is a fixed rate probability-based arithmetic code. By fixed rate it is meant that given the length of a data string, its channel string will have a known length within a few channel time units. The difference between actual length and predicted length is bounded above by a few bits no matter how long the data string. The predicted vs. actual length is due to the "end effect" property of all arithmetic codes. Prior-art fixed rate arithmetic codes are length based, wherein the augend is a function of the fractional length and the length recursion proceeds by addition. No rounding is done during the coding process.