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US 8,020,078 B2Granted
Methods and apparatus for reducing error floors in message passing decoders
AssigneeQUALCOMM Incorporated
InventorTom Richardson
Life of this patent
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AssigneeQUALCOMM Incorporated
InventorTom Richardson
Estimating the term…
An iterative message passing decoder, e.g., an LDPC decoder, operating in conjunction with a soft input-soft output signal processing unit, e.g., an ISI detector, has an error floor performance region influenced by the decoder's sub-optimal message passing nature. Error floor reduction is achieved by a simple message re-initialization mechanism. Decoder edge states, e.g., constraint to variable node messages in decoder memory, are reinitialized, e.g., for an iteration, during the decoding after soft values provided by signal processing unit have improved. During the message re-initialization and for some subsequent amount of iterative decoder processing, extrinsic information fed back from the decoder to the signal processing unit and/or soft values delivered to the decoder from the signal processing unit, in an outer communications loop, is temporarily frozen, e.g., using a switch and a buffer. Then, the outer communications loop is restored as the decoding continues, achieving improved decoding performance.
An apparatus for performing decoding operations, said apparatus comprising:
An apparatus for performing decoding operations, said apparatus comprising:
A method for performing decoding operations, said method comprising:
A memory having a routine for controlling a processor to perform the following operations:
Dependencies are inferred from the claim text.