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Title Multiuser Detection Algorithms for CDMA based on the Massage Passing Algorithms (in Japanese)
Authors Shunsuke Horii 、Tota Suko 、Toshiyasu Matsushima
Released Year 2006
Format International Conference
Category Others
Jounal Name IEICE technical report substituted for proc. of 2006 Hawaii, IEICE and SITA Joint Conference on Information Theory (HISC2006)
Jounal Page vol.106, no.60, IT2006-16, pp.17-22
Published Year 2006
Published Month 5
Abstract
(English)
Optimal multiuser detection for the direct sequence code division multiple access (DS-CDMA) channel is known to be NP-hard, i.e., its computational complexity increase exponentially with the number of users. If regarding the detection problem as the probabilistic inference problem, one of the principled approaches to derive the algorithm for the detection problem is to apply the message passing algorithm such as the belief propagation (BP) algorithm and the concave convex procedure (CCCP) on a graph after obtaining the graphical representation of the problem. But it has been reported that the computational complexity of the resulting algorithms are exponentially increasing as the number of users increases since the graphical representation of the detection problem become a complete bipartite graph. Consequently it has been proposed that to reduce the computational complexity through approximating the algorithms with the central limit theorem.\\
 In this paper, we suggest that we can reduce the computational complexity of the message passing algorithms for the detection problem by converting the graph structure, and as a result, the message passing algorithms can be applied in the same way of the definition without approximation.
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