Computation of soft bits for a turbo decoder in a communication receiver
AssigneeNEC Corporation
InventorThanh Ngoc Bui
Life of this patent
Estimating the term…
Abstract
A device (20) for computing a threshold Sthi used in demodulating a quadrature amplitude modulated (QAM) signal to generate a plurality of soft bits per received symbol for input to a turbo decoder, the device including: means (30) for computing the mean amplitude A of the received symbols and multiplying the mean amplitude A by of the received symbols and multiplying the mean amplitude A by a constant Ci for a square QAM constellation with 4m points, such that Sthi=A×Ci where m is a positive integer and i is a positive integer from 1 to (√4m-1)−1.
Claims11
A method on a communication receiver having a soft bit generator and a turbo decoder, the method for computing a threshold Sthi used in demodulating a quadrature amplitude modulated (QAM) signal received by the communication receiver to generate a plurality of soft bits per received symbol for input to the turbo decoder, the method including the steps of:
- the soft bit generator:
- computing a mean amplitude A of the received symbols;
- multiplying the mean amplitude A by a constant Ci for a square QAM constellation with 4m points, such that
- Sthi=A×Ci
- where m is a positive integer and I is a positive integer from 1 to (√{square root over (4m-1)})−1;
- computing one or more of the soft bits from the threshold Sthi;
- and
- outputting the computed soft bits to the turbo decoder.
A device within a communication receiver for computing a threshold Sthi used in demodulating a quadrature amplitude modulated (QAM) signal received by the communication receiver to generate a plurality of soft bits per received symbol for input to a turbo decoder, the device including:
- means for computing a mean amplitude A of the received symbols and multiplying the mean amplitude A by of the received symbols and multiplying the mean amplitude A by a constant Ci for a square QAM constellation with 4m points, such that
- Sthi=A×Ci
- where m is a positive integer and i is a positive integer from 1 to (√{square root over (4m-1)})−1;
- means for computing one or more of the soft bits from the threshold Sthi;
- and
- means for outputting the computed soft bits to the turbo decoder.
A device within a communication receiver for generating soft bits per received symbol for input to a turbo decoder used in demodulating a quadrature amplitude modulated (QAM) signal received by the communication receiver, the device including:
- means for computing a mean amplitude A of the received symbols and multiplying the mean amplitude A by a constant Ci for a square QAM constellation with 4m points, such that
- Sthi=A×Ci
- where m is a positive integer and i is a positive integer from 1 to (√{square root over (4m-1)})−1;
- and
- means for computing one or more of the soft bits from the threshold Sthi;
- and
- means for outputting the computed soft bits to the turbo decoder.
Dependencies are inferred from the claim text.