Log approximate factor operation manner for the decoding in the receiver of the portable communication system and log

摘要

And apparatus (LLR) calculation method log approximation ratio for decoding in a receiver of a mobile communication system is provided. Such a method and apparatus is, domain bits that determines the selection bits to distinguish four quadrants of the constellation diagram of the signal points of transmission symbols, and divides the signal points in each area of ​​4 quadrants by the modulation order of the transmitted symbols After divided into real and imaginary components of the received signal as a function of the number of area bits to determine, is determined, and computes the absolute value of the real and imaginary components, and repeating the operation to origin movement, for the selected bit I calculates the log approximation ratio. It is also possible each time the received signal and origin movement is received, to reduce the log approximation ratio for the corresponding domain bits.