| 摘要 |
A multilevel coded modulation scheme trellis encodes a portion of the input data, and the resulting encoded stream is used to identify a partic ular one of a predetermined number of subsets of symbols of a predetermined signal constellation. The remaining input data is coded using a Reed-Solomon (RS) code whose output is used to select for transmission a particular symbol from the identified subset. In applications in which phase hits or other channel phenomen a may cause the received signal points to be phase-rotated versions of the signal points that were transmitted, differential encoding is included in the overall c oded modulation scheme. In different embodiments, the differential encoding/decoding and RS encoding/decoding are in different orders. In one such embodiment, overlapped multilevel codes are used to preserve the advantages afforded by taki ng a multilevel coding approach.
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