METHOD AND APPARATUS FOR CALCULATING LOG LIKELIGDDO RATIO IN COMMUNICATION SYSTEM

摘要

A method and an apparatus for calculating an LLR in a communication system are provided to obtain an accurate LLR value without a large complexity by using a recursive calculation scheme. An LLR(Log Likelihood Ratio) in a communication system to adopt a high order modulation scheme, is calculated. A closest index to a predetermined bit of a received symbol is set as a start index(410). An initial value for a partial LLR function is calculated according to a distance from the start index to a current index(430). Partial LLR values for respective indexes are calculated by using a recursion process according to the distance from the calculated initial value to the current index(440). All LLR values for the received symbols are calculated based on the calculated LLR values(450).