Open AccessEvaluation of an error correction function using correlation characteristics of spread codes in CDMA-based transmission methods
Author(s) -
Hidetaka Mochizuki,
Hideo Nakamura
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1780/1/012036
Subject(s) - code division multiple access , computer science , transmission (telecommunications) , electronic engineering , algorithm , qam , quadrature amplitude modulation , modulation (music) , correlation function (quantum field theory) , bit error rate , telecommunications , decoding methods , engineering , physics , acoustics , spectral density
In previous researches, we have proposed novel modulation methods such as the CDMA-QAM method in which Code-Division Multiple Access (CDMA) and Quadrature Amplitude Modulation (QAM) are combined, and applied these methods for improvement of railway signalling systems. Although a rail is used as a transmission medium, there are severe conditions for transmission, such as strong attenuation at frequencies above about 10 kHz. To overcome this restriction, we attempted to improve the S/N characteristics in our proposed method. Specifically, we focused on correlation characteristics of spread codes which are used in CDMA. In this paper, we show that an error correction function that does not require additional bits for such correction can be realized by using the correlation characteristics. We evaluated the effectiveness of this correction method and conducted computer simulations in which the method was employed for CDMA-based transmission.