Decoder employing viterbi decoding method for decoding coded multi-valued signal
AssigneeFujitsu Limited
InventorsKohji Takahashi, Tadashi Nakamura, Kenichi Oide
Life of this patent
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Abstract
A Viterbi decoder decodes a received signal having Ich and Qch components obtained by modulating a convolutional coded multi-valued QAM signal. The Viterbi decoder includes a first unit which inputs the received signal having the Ich and Qch components, a second unit which finds Euclidean distance between a predetermined signal point, which is one of a plurality of predetermined signal points allocated on a plane formed of Ich and Qch axes orthogonally crossed, and a signal point of the received signal, and a third unit which performs a Viterbi decoding based on the Euclidean distance obtained by the second unit.
Claims16
A Viterbi decoder for decoding a received signal having Ich and Qch components, which are obtained by demodulating a convolutional coded multi-valued quadrature amplitude modulated signal, the Viterbi decoder comprising:
- first means for inputting the received signal having the Ich and Qch components, which respectively include a main signal and an error signal;
- second means operatively connected to the first means (FF1) for finding Euclidean distance between a predetermined signal point, which is one of a plurality of predetermined signal points allocated on a plane formed of Ich and Qch axes orthogonally crossed, and a signal point corresponding to the Ich and Qch components of the received signal;
- and
- third means operatively connected to the second means for performing a Viterbi decoding based on the Euclidean distance obtained by the second means,
- wherein the plane has a plurality of domains divided in advance, and the second means includes a first circuit for providing a selection signal, which corresponds to one of the plurality of domains, where the received signal is positioned, and a second circuit for obtaining a calculated Euclidean distance value by applying the error signals of the Ich and Qch components of the received signal to a calculating expression selected by the selection signal.
Dependencies are inferred from the claim text.