Patent Number: 7,089,481

Title: High speed arithmetic operations for use in turbo decoders

Abstract: Techniques for performing substantially concurrent add-compare-select-add operations and substantially concurrent compare-select-add operations for use in turbo decoders are provided. In one aspect of the invention, a technique for processing data in accordance with a turbo decoder comprises the following steps. Data values of two sets of input data are respectively added to generate a set of sums. Substantially concurrent with the addition step, correction values are respectively added to the sums to generate a set of corrected sums. Substantially concurrent with the respective input data value and correction value addition steps, the sums are compared against one another, and an absolute value of a difference between the sums is compared against base and bound values. Then, one of the corrected sums is selected based on the comparison steps. Preferably, respective sub-steps within the input value addition step, the correction value addition step, and the comparison step are performed concurrently.

Inventors: D'Arcy; Paul Gerard (Chelmsford, MA), Pillai; Rajan V. K. (Atlanta, GA)

Assignee: Agere Systems Inc.

International Classification: H03M 13/00 (20060101)

Expiration Date: 8/08/02018