Patent ID: 7860194
Filing Date: 2010-12-28
Classification: H04B,H04L

Abstract:
1. An apparatus for normalizing input soft metric to a channel decoder in a wireless communication system, comprising: a demapper for generating a soft metric per bit for a received modulated symbol; and a normalizer for receiving the soft metric, computing a normalized log likelihood ratio (LLR) by using a modulation order of the received modulated symbol and a noise variance value to the soft metric, transforming the normalized LLR into a number of bits, and outputting the transformed LLR to the channel decoder, wherein the normalizer comprises: a transformation table for transforming the noise variance value computed from a channel estimate of the received modulated symbol into a ratio of a constant value to the noise variance value; a multiplier for multiplying the soft metric output from the demapper by the received ratio of the constant value to the noise variance value, and outputting the normalized LLR; and a rounding/clipping section for transforming the normalized LLR into the number of bits and outputting the transformed LLR to the channel decoder.