Reducing Detection Complexity of MIMO-OFDM by Using New Nulling Vectors

Ming LEI  Hiroshi HARADA  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.2   pp.392-396
Publication Date: 2007/02/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.2.392
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
MIMO,  OFDM,  V-BLAST,  nulling vector,  

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We propose new nulling vectors for the subcarrier grouping based low-complexity detection scheme of V-BLAST (vertical Bell Laboratories layered space-time) coded MIMO-OFDM. In each subcarrier group, the center subcarrier uses the conventional ZF-DFE (zero-forcing decision-feedback- equalization) algorithm and the non-center subcarriers use the reduced-complexity ZF-DFE with the new nulling vectors. The subcarrier grouping based detection scheme, ZF-DFE-SG, can significantly reduce the detection complexity compared with ZF-DFE-EX which exhaustively applies the conventional ZF-DFE at each subcarrier independently. The performance loss is very small. We conduct the simulations for channel coded V-BLAST OFDM system under estimated channel frequency responses. It is shown the complexity can be reduced by 80.6% with only 1.0 dB performance loss for a 44 system.