The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 2006
Filed:
Sep. 12, 2001
Hau Thien Tran, Irvine, CA (US);
Kelly B. Cameron, Irvine, CA (US);
Thomas A. Hughes, Dana Point, CA (US);
Hau Thien Tran, Irvine, CA (US);
Kelly B. Cameron, Irvine, CA (US);
Thomas A. Hughes, Dana Point, CA (US);
Broadcom Corporation, Irvine, CA (US);
Abstract
Method and apparatus for Min star calculations in a Map decoder. Min star calculations are performed by a circuit that includes a first circuit that performs an Min(A,B) operation simultaneously with a circuit that calculates a −log(1+e) value. The sign bit of the A−B calculation is used to select whether A or B is a minimum. The A−B calculation is also used to select either −log(1+e) or −log(1+e) as the correct calculation. In order to hasten the selection of either −log(1+e) or −log(1+e) as the correct calculation the apparatus does not wait for the A−B calculation to complete. Any bit of the A−B calculation between the third bit and final (sign bit) can be used for the selection. If an incorrect value is selected a log saturation circuit may correct the value. In addition an offset may be added −log(1+e) or −log(1+e) to assure that the calculation does not become negative, necessitating the use of an additional sign bit thereby increasing circuit complexity and slowing down the calculation. Additionally the log terms are computed based on a partial result of the A−B calculation.