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Angle differential‐QAM scheme for resolving phase ambiguity in continuous transmission system
Author(s) -
Hwang JengKuang,
Chiu YuLun,
Liao ChiaShu
Publication year - 2008
Publication title -
international journal of communication systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.344
H-Index - 49
eISSN - 1099-1131
pISSN - 1074-5351
DOI - 10.1002/dac.914
Subject(s) - differential coding , quadrature amplitude modulation , qam , computer science , additive white gaussian noise , fading , decoding methods , phase shift keying , transmission (telecommunications) , differential (mechanical device) , algorithm , transmission system , telecommunications , topology (electrical circuits) , channel (broadcasting) , mathematics , physics , bit error rate , combinatorics , thermodynamics
An angle differential quadrature amplitude modulation (ADQAM) scheme is proposed to solve phase ambiguity problem in non‐data‐aided continuous transmission system with square QAM constellation. Starting from the 16‐ADQAM case, we derive differential encoding and decoding schemes in terms of two differential angles and use a solar system analogy for explanation. The 16‐ADQAM system incurs only about 0.5‐dB performance degradation compared with the coherent 16‐QAM system under AWGN channel. Generalization of flat fading channel and higher‐level ADQAM is straightforward. Copyright © 2007 John Wiley & Sons, Ltd.