US 6,487,694 B1 · Method and apparatus for turbo-code decoding a convolution encoded data frame using symbol-by-symbol traceback and HR-SOVA

Abstract

The apparatus includes a first SOVA decoder that generates a first path reliability value from a channel value, a parity symbol and a first a priori likelihood value. A first decorrelation unit generates a first extrinsic symbol reliability value by decorrelating the channel value and the first a priori likelihood value from the path reliability value. A first symbol reliability saturation unit saturates the first extrinsic symbol reliability value to generate a first saturated extrinsic symbol reliability value. A first interleaver interleaves the first saturated extrinsic symbol reliability value to generate a second a priori likelihood value. A second interleaver interleaves the channel value to generate an interleaved channel value. A second SOVA decoder generates a second path reliability value from an interleaved parity symbol, the second a priori likelihood value, and the interleaved channel value. A second decorrelation unit generates 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. A second symbol reliability saturation unit saturates the second extrinsic symbol reliability value to generate a second saturated extrinsic symbol reliability value. A first de-interleaver de-interleaves the second saturated extrinsic symbol reliability value to generate the first a priori likelihood value. A second de-interleaver de-interleaves the second extrinsic symbol reliability value to generate a decoded message. Additionally, the path reliability value are saturated. Advantages include simplified hardware implementations having improved BER characteristics and faster convergence, requiring fewer decoding iterations to generate a result.

Claims17

Dependent claims

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.

8 more elements

A TURBO-code decoding apparatus configured to decode a convolution encoded data frame using symbol-by-symbol traceback and APRI-SOVA, the apparatus comprised of:

a first SOVA decoder configured to generate a first path reliability value from a channel value and a parity symbol of the encoded frame, and a first a priori likelihood value;
a first decorrelation unit configured to generate a first extrinsic symbol reliability value by decorrelating the channel value and the first a priori likelihood value from the path reliability value;
a first symbol reliability saturation unit configured to saturate the first extrinsic symbol reliability value to generate a first saturated extrinsic symbol reliability value;
a first interleaver configured to interleave the first saturated extrinsic symbol reliability value to generate a second a priori likelihood value;
a second interleaver configured to interleave the channel value to generate an interleaved channel value;
a second SOVA decoder configured to generate 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;
a second decorrelation unit configured to generate 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;
a second symbol reliability saturation unit configured to saturate the second extrinsic symbol reliability value to generate a second saturated extrinsic symbol reliability value;
a first de-interleaver configured to de-interleave the second saturated extrinsic symbol reliability value to generate the first a priori likelihood value as an input to the first SOVA decoder;
and
a second de-interleaver configured to de-interleave the second path reliability value to generate a decoded message of the convolution encoded data frame.

8 more elements

Dependencies are inferred from the claim text.

Method and apparatus for turbo-code decoding a convolution encoded data frame using symbol-by-symbol traceback and HR-SOVA

Life of this patent

Method and apparatus for turbo-code decoding a convolution encoded data frame using symbol-by-symbol traceback and HR-SOVA

Life of this patent

Abstract

Claims17