TURBO DECODER USING BINARY LOGMAP ALGORITHM AND PERFORMING METHOD OF THE SAME

摘要

PURPOSE: A turbo decoder using binary logmap algorithm and a performing method of the same are provided to perform a high-rate decoding by applying a binary logmap algorithm to a turbo decoder. CONSTITUTION: A split(61) divides an addition of metric into an integer part and a decimal part. A comparator(62) seeks for a maximum integer value and a minimum integer value from the integer part. A subtracter(64) seeks for a difference between the maximum integer value and the minimum integer value. A lookup table(63) seeks for a binary exponential value from the decimal part. A shifter(65) shifts the binary exponential value as much as the difference between the maximum integer value and the minimum integer value. An adder(66) adds the shifted binary exponential value to the decimal part. A log preprocessor(67) and a lookup table(68) perform a binary logarithmic process of the decimal part and seek for an ultimate value of the decimal part. An adder(69) adds the ultimate value to the decimal part and seeks for an ultimate binary function value. A subtracter(80) seeks for an LLR(log-likelihood ratio).