An Effective CDMA Multi-User Detection Scheme-Orthogonal Decision-Feedback Detection and Its Performance Analysis

Xiao Hua CHEN  Hak-Keong SIM  Pang Shyan KOOI  

IEICE TRANSACTIONS on Communications   Vol.E80-B   No.1   pp.145-155
Publication Date: 1997/01/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Mobile Communication
CDMA,  multi-user detection,  decision-feedback,  

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A novel CDMA multi-user detection scheme, orthogonal decision-feedback detector (ODFD), is proposed for a synchronous CDMA system in this paper. It is robust for its near-far resistance and high multi-user detection efficiency with a performance similar to that of decorrelating decision-feedback detector (DDFD) but with a reduced complexity. The ODFD scheme employs a match-filter bank that matches a set of ortho-normal sequences. The ortho-normal sequences are generated by the Gram-Schmidt orthogonalisation procedure based on the spreading codes. The ODFD algorithm involves only with the ortho-normal coefficient-matrix which requires no frequent recalculations even when system parameters change. Successive decision-feedback detection is carried out immediately at the output of the ODFD match-filter bank without matrix inversion operations, resulting in a much simplified structure.