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Sicom, Inc.

Mark J Vanderaar

William H Thesling

A communication system (11) uses concatenated coding in which an inner code is configured to match the needs of an outer code. The inner code is implemented through a pragmatic trellis coded modulation encoder (18) and decoder (34). A parser (50) of the encoder (18) distributes fewer than one user information bit per unit interval (66) to a convolutional encoder (58) which generates at least two convolutionally encoded bits for each user information bit it processes. Exactly one of the convolutionally encoded bits is phase mapped (56) with at least two user information bits during each unit interval (66). The decoder (34) detects a frame sync pattern (48) inserted into the user information bits to resolve phase ambiguities. Phase estimates are convolutionally decoded (100) to provide decoded data estimates that are then used to selectively rotate the phase estimates prior to routing the phase estimates to a slice detector (118).

Pragmatic encoder and method therefor

The optimum decoding of component codes in Block Coded Modulation (BCM) schemes requires the use of the Log-Likelihood Ratio (LLR) as the signal metric. The essence of the invention is a means of accurately approximating the computation of the LLR in a way which is simple to implement directly. The invention, the Log-Likelihood Ratio Planar Approximation (LLRPA), mathematically consists solely of planar equations with fixed point arithmetic that provides both an accurate estimate of the LLR and is easily realized in electronic hardware.

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Medina, OH, United States of America

Mark J Vanderaar