| 摘要 |
TTCM (Turbo Trellis Coded Modulation) decoder design. The design also adapts to any number of devices that perform decoding of Trellis Code Modulation (TCM) signals. After performing initial symbol processing within a data block to generate a number of check point values, the design selectively re-calculates some forward metrics (alphas) and backward metrics (betas), and the design is able to calculate extrinsic (ext) information for each symbol within the data block successively. The data block is subdivided into a number of sub-blocks that are intelligently processed to enable extremely fast processing. Generally speaking, the design performs initial processing starting from both block ends, and upon approaching the block middle, the design begins to process the block using skip backs to previous sub-blocks. The design employs a great deal of parallel and simultaneously processing to provide for very fast computation of the various values required to decode the block.
|
