DocumentCode :
23357
Title :
Max-Log-MAP Soft Demapper with Logarithmic Complexity for 
-PAM Signals
Author :
Xiang Liu ; Kosakowski, Martin
Author_Institution :
BlackBerry Deutschland GmbH, Bochum, Germany
Volume :
22
Issue :
1
fYear :
2015
fDate :
Jan. 2015
Firstpage :
50
Lastpage :
53
Abstract :
A max-log-MAP soft demapping algorithm with logarithmic complexity is proposed for M-PAM signals. Its algorithm complexity is only Θ(logM) for M-PAM signals, in contrast to Θ(MlogM) as achieved by the conventional max-log-MAP algorithm using exhaustive search. The algorithm applies to both Gray-coded and natural-coded signals. The max-log-MAP algorithm with logarithmic complexity may be straightforwardly extended to rectangular QAM signals when the rectangular QAM signal can be decomposed into two independent PAM signals.
Keywords :
computational complexity; maximum likelihood estimation; pulse amplitude modulation; quadrature amplitude modulation; Θ(MlogM); Θ(logM); Gray-coded signal; M-PAM signals; exhaustive search; logarithmic complexity; max-log-MAP soft demapper; max-log-MAP soft demapping algorithm; natural-coded signal; rectangular QAM signal; Approximation algorithms; Approximation methods; Complexity theory; Decoding; Pragmatics; Quadrature amplitude modulation; Signal processing algorithms; Demapper; LLR; PAM; QAM; max-log-MAP;
fLanguage :
English
Journal_Title :
Signal Processing Letters, IEEE
Publisher :
ieee
ISSN :
1070-9908
Type :
jour
DOI :
10.1109/LSP.2014.2346786
Filename :
6876151
Link To Document :
