Enhancement of MCMV Capability for Multiuser Detection under Spreading Code Mismatch

Ann-Chen CHANG  Jeng Han SHIU  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.11   pp.3303-3306
Publication Date: 2007/11/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.11.3303
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
MC-CDMA,  multiuser detection,  eigenstructure,  spreading code mismatch,  

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This letter deals with multiuser detection under imprecise knowledge of the received signature codes of all active users for multicarrier code division multiple access (MC-CDMA) systems. The weight vector of the modified multiple constrained minimum variance (MMCMV) is found by projecting the multiple constrained minimum variance (MCMV) weight vector onto a vector subspace constructed from the eigenstructure of the correlation matrix. However, MMCMV still cannot handle the large code-mismatch. Shaping the noise subspace with all estimated active spreading codes, we present an effective approach to achieve more robust capabilities than the MMCMV. Computer simulations show the effectiveness of the proposed detector.