Patent ID: 9143273
Filing Date: 2015-09-22
Classification: H04L

Abstract:
1. A multilevel differential decoding device for a QAM modulation communication system which uses QAM modulation, comprising: a synchronous detection part for receiving a signal in which differential encoding has been performed on first two most significant bits of an N-bit transmission symbol, where N≧4 holds; an MSB coordinate rotating part for performing coordinate rotation based on information of the first two most significant bits out of a reception symbol of the signal received via the synchronous detection part; an MSB symbol likelihood generating part for generating likelihood with respect to the first two most significant bits after differential decoding, with use of two sets of bit strings at different points in time for which coordinate rotation has been performed based on the first two most significant bits; an LSB symbol likelihood generating part for generating likelihood with respect to less significant bits out of the reception symbol of the received signal that are (N−2) bits on a least significant side; and a soft decision error correction decoding part for generating a decoded signal by performing error correction decoding processing with use of the likelihood of the first two most significant bits which has been generated by the MSB symbol likelihood generating part and the likelihood of the less significant bits which has been generated by the LSB symbol likelihood generating part.