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:
Oct. 30, 2012
Filed:
Apr. 21, 2009
Dayong Chen, Cary, NC (US);
Dayong Chen, Cary, NC (US);
Telefonaktiebolaget L M Ericsson (Publ), Stockholm, SE;
Abstract
A demodulator is provided that functions as a reduced-state equalizer and produces reliable soft bit values. According to an embodiment, soft bit values are generated for a sequence of transmitted symbols using a demodulator by updating an M-state trellis managed by the demodulator responsive to a transition from symbol time n−1 to symbol time n, where M is a function of the number of bits per symbol in the sequence of transmitted symbols. Survivor metrics associated with the M states of the trellis are saved each symbol time so that the demodulator can calculate soft bit values with regard to transitions from symbol time n+D−1 to symbol time n+D. The survivor metrics indicate the probability that each respective state represents the transmitted symbol associated with symbol time n+D−1. The trellis is traced back through to calculate soft bit values for a symbol detected at symbol time n−D based on survivor metrics saved for the M states at symbol time n−D.