US 7,587,659 B2
Efficient front end memory arrangement to support parallel bit node and check node processing in LDPC (Low Density Parity Check) decoders
Hau Thien Tran, Irvine, Calif. (US); Kelly Brian Cameron, Irvine, Calif. (US); and Ba-Zhong Shen, Irvine, Calif. (US)
Assigned to Broadcom Corporation, Irvine, Calif. (US)
Filed on Jun. 30, 2005, as Appl. No. 11/171,727.
Application 11/171727 is a continuation in part of application No. 10/264647, filed on Oct. 04, 2002, granted, now 7,065,695, filed on Jun. 20, 2006.
Claims priority of provisional application 60/615722, filed on Oct. 04, 2004.
Claims priority of provisional application 60/632237, filed on Dec. 01, 2004.
Claims priority of provisional application 60/384698, filed on May 31, 2002.
Claims priority of provisional application 60/384464, filed on May 31, 2002.
Prior Publication US 2005/0262421 A1, Nov. 24, 2005
Int. Cl. H03M 13/03 (2006.01); H03M 13/00 (2006.01)
U.S. Cl. 714—794  [714/758] 10 Claims
OG exemplary drawing
 
1. A decoder that is operable to decode an LDPC (Low Density Parity Check) coded signal, the decoder comprising:
a controller that provides a modulation/code signal indicating at least one of a respective code rate and a respective modulation corresponding to each respective symbol of the LDPC coded signal, each symbol of the LDPC signal having a respective in-phase (I) value, a respective quadrature (Q) value, and a respective signal to noise ratio;
a metric generator circuitry that includes a symbol metric calculator circuitry and a bit metric calculator circuitry, wherein:
the symbol metric calculator circuitry, coupled to the controller, processes a respective symbol's I value using a respective plurality of predetermined I coefficients and processes the respective symbol's Q value using a respective plurality of predetermined Q coefficients selected based on the modulation/code signal thereby generating a plurality of symbol metrics corresponding to the respective symbol;
the bit metric calculator circuitry, coupled to the symbol metric calculator circuitry and to the controller, includes a plurality of min* (min-star) processing circuitries, that processes the plurality of symbol metrics corresponding to the respective symbol thereby generating a respective plurality of bit metrics based on the modulation/code signal;
a plurality of macro circuitries, coupled to the bit metric calculator circuitry, such that each of the plurality of macro circuitries includes:
a corresponding metric memory that performs dual port memory management on respective pluralities of bit metrics; and
a corresponding plurality of bit/check processor circuitries that employs at least one respective plurality of bit metrics to update bit edge messages and check edge messages; and
a hard limiter, coupled to the plurality of macro circuitries, that generates a hard decision corresponding to at least one bit encoded within the LDPC coded signal based on a most recently updated plurality of bit edge messages.