摘要 |
A multi-level encoded signal is encoded according to at least an upper-level code and a lower-level code. In a receiver, a modified type of a multistage decoder is deployed. The upper-level code is decoded to produce a sequence of tentative upper-level coding decisions independently of the lower-level code. The lower-level code is next decoded in such a way that the decoding is conditioned upon at least one of the tentative upper-level decisions. The lower-level decoder thereby produces a sequence of lower-level decisions. The upper-level code is then decoded a second time, this time conditioned upon at least one of the lower-level decisions, to produce a second, more reliable sequence of upper-level coding decisions. The lower-level decision sequence and the second upper-level decision sequence are delivered from the decoder as output sequences.
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