Broadcom Corporation

Thomas A Hughes, Jr

Kelly Brian Cameron

Hau Thien Tran

Ba-Zhong Shen

Christopher R Jones

A method for parallel concatenated (Turbo) encoding and decoding. Turbo encoders receive a sequence of input data tuples and encode them. The input sequence may correspond to a sequence of an original data source, or to an already coded data sequence such as provided by a Reed-Solomon encoder. A turbo encoder generally comprises two or more encoders separated by one or more interleavers. The input data tuples may be interleaved using a modulo scheme in which the interleaving is according to some method (such as block or random interleaving) with the added stipulation that the input tuples may be interleaved only to interleaved positions having the same modulo-N (where N is an integer) as they have in the input data sequence. If all the input tuples are encoded by all encoders then output tuples can be chosen sequentially from the encoders and no tuples will be missed. If the input tuples comprise multiple bits, the bits may be interleaved independently to interleaved positions having the same modulo-N and the same bit position. This may improve the robustness of the code. A first encoder may have no interleaver or all encoders may have interleavers, whether the input tuple bits are interleaved independently or not. Modulo type interleaving also allows decoding in parallel.

Parallel concatenated code with soft-in soft-out interactive turbo decoder

Parallel concatenated code with soft-in-soft-out interactive turbo decoder

Inverse function of min*:min*&#x2212; (inverse function of max*:max*&#x2212;). Two new parameters are employed to provide for much improved decoding processing for codes that involve the determination of a log corrected minimal and/or a log corrected maximal value from among a number of possible values. Examples of some of the codes that may benefit from the improved decoding processing provided by the inverse function of min*:min*&#x2212; (and/or inverse function of max*:max*&#x2212;) include turbo coding, parallel concatenated trellis coded modulated (PC-TCM) code, turbo trellis coded modulated (TTCM) code, and low density parity check (LDPC) code among other types of codes. The total number of processing steps employed within the decoding of a signal is significantly reduced be employing the inverse function of min*:min*&#x2212; (and/or inverse function of max*:max*&#x2212;) processing.

Inverse function of min*:min*- (inverse function of max*:max*-)

Single stage implementation of min*, max*, min and/or max to perform state metric calculation in soft-in soft-out (SISO) decoder. This allows for calculation of state metrics in an extremely efficient, fast manner. When performing min or max calculations, comparisons are made using 2 element combinations of the available inputs. Subsequently, logic circuitry employs the results of the 2 element comparisons the smallest (min) or largest (max) input. The max or min implementations may be employed as part of the max* and/or min* implementations. For max* and/or min* implementations, simultaneous calculation of appropriate values is performed while determining which input is the smallest or largest. Thereafter, the determination of which input is the smallest or largest is used to select the appropriate resultant value (of the values calculated) for max* and/or min*. Various degrees of precision are employed for the log correction values within the max* and/or min* implementations.

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Dana Point, CA, United States of America

Thomas A Hughes, Jr