Title :
A low complexity soft demapping method for expanded M-QAM constellations
Author :
Kinjo, Shigenori
Author_Institution :
Japan Coast Guard Acad., Kure, Japan
Abstract :
Wireless communication systems based on the Tomlinson-Harashima precoding (THP) suffer from modulo operation error in noisy environments. The error leads to a fatal performance degradation when soft-input forward error correction is used because the conventional soft demapper provides erroneous log-likelihood ratio (LLR). In this paper, we propose a low complexity soft demapping method for expanded M-QAM constellations for the THP systems. We apply the conventional fast demapping procedure to the expanded M-QAM constellations, and show that the computational complexity of the developed demapper is successfully reduced. Computer simulations are given to show the effectiveness of the proposed demapper.
Keywords :
MIMO communication; computational complexity; forward error correction; quadrature amplitude modulation; radio networks; statistical testing; MIMO communication systems; THP systems; Tomlinson-Harashima precoding; computer simulations; erroneous log-likelihood ratio; expanded M-QAM constellations; fatal performance degradation; low complexity soft demapping method; modulo operation error; noisy environments; soft-input forward error correction; wireless communication systems; Bit error rate; Computational complexity; Forward error correction; MIMO; Receivers; Vectors;
Conference_Titel :
Circuits and Systems (APCCAS), 2014 IEEE Asia Pacific Conference on
Conference_Location :
Ishigaki
DOI :
10.1109/APCCAS.2014.7032738
