A low complexity soft demapping method for expanded M-QAM constellations

Author

Kinjo, Shigenori

Author_Institution

Japan Coast Guard Acad., Kure, Japan

fYear

2014

fDate

17-20 Nov. 2014

Firstpage

137

Lastpage

140

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems (APCCAS), 2014 IEEE Asia Pacific Conference on

Conference_Location

Ishigaki

Type

conf

DOI

10.1109/APCCAS.2014.7032738

Filename

7032738