Title :
Improvement of BP-based CDMA multiuser detection by spatial coupling
Author :
Takeuchi, Keigo ; Tanaka, Toshiyuki ; Kawabata, Tsutomu
Author_Institution :
Dept. Commun. Eng. & Inf., Univ. of Electro-Commun., Chofu, Japan
fDate :
July 31 2011-Aug. 5 2011
Abstract :
Kudekar et al. proved that the belief-propagation (BP) threshold for low-density parity-check codes can be boosted up to the maximum-a-posteriori (MAP) threshold by spatial coupling. In this paper, spatial coupling is applied to randomly-spread code-division multiple-access (CDMA) systems in order to improve the performance of BP-based multiuser detection (MUD). Spatially-coupled CDMA systems can be regarded as multi-code CDMA systems with two transmission phases. The large-system analysis shows that spatial coupling can improve the BP performance, while there is a gap between the BP performance and the individually-optimal (IO) performance.
Keywords :
code division multiple access; maximum likelihood decoding; multiuser detection; parity check codes; BP-based CDMA MUD; IO performance; MAP threshold; belief-propagation-based code-division multiple-access multiuser detection; individually-optimal performance; large-system analysis; low-density parity-check code; maximum-a-posteriori threshold; multicode CDMA system; spatial coupling; Couplings; Equations; Mathematical model; Multiaccess communication; Multiuser detection; Potential energy; Receivers;
Conference_Titel :
Information Theory Proceedings (ISIT), 2011 IEEE International Symposium on
Conference_Location :
St. Petersburg
Print_ISBN :
978-1-4577-0596-0
Electronic_ISBN :
2157-8095
DOI :
10.1109/ISIT.2011.6033789
