Patent ID: 6487694
Filing Date: 2002-11-26
Classification: H03M

Abstract:
A method for TURBO-code decoding a convolution encoded data frame using symbol-by-symbol traceback and APRI-SOVA, the method comprising steps of:generating a first path reliability value from a channel value and a parity symbol of the encoded frame, and a first a priori likelihood value using a first SOVA decoder; generating a first extrinsic symbol reliability value by decorrelating the channel value and the first a priori likelihood value from the first path reliability value; saturating the first extrinsic symbol reliability value to generate a first saturated symbol reliability value; interleaving the first saturated reliability value to generate a second a priori likelihood value; interleaving the channel value to generate an interleaved channel value; generating a second path reliability value from an interleaved parity symbol of the encoded frame, the second a priori likelihood value, and the interleaved channel value using a second SOVA decoder; generating a second extrinsic symbol reliability value by decorrelating the interleaved channel value and the second a priori likelihood value from the second path reliability value; saturating the second extrinsic symbol reliability value to generate a second saturated symbol reliability value; de-interleaving the second saturated symbol reliability value to generate the first a prior value as an input for the first SOVA decoder; and repeating the aforementioned steps until each symbol of the convolution encoded data frame is processed and the convolution encoded data frame is decoded.