Frequency-Domain Iterative Parallel Interference Cancellation for Multicode Spread-Spectrum MIMO Multiplexing

Akinori NAKAJIMA  Deepshikha GARG  Fumiyuki ADACHI  

IEICE TRANSACTIONS on Communications   Vol.E91-B   No.5   pp.1531-1539
Publication Date: 2008/05/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e91-b.5.1531
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
spread-spectrum,  MIMO multiplexing,  frequency-domain iterative PIC,  mobile communication,  

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Very high-speed data services are demanded in the next generation wireless systems. However, the available bandwidth is limited. The use of multi-input multi-output (MIMO) multiplexing can increase the transmission rate without bandwidth expansion. For high-speed data transmission, however, the channel becomes severely frequency-selective and the achievable bit error rate (BER) performance degrades. In our previous work, we proposed the joint use of iterative frequency-domain parallel interference cancellation (PIC) and two-dimensional (2D) MMSE-FDE for the non-spread single-carrier (SC) transmission in a frequency-selective fading channel. The joint use of PIC and 2D MMSE-FDE can effectively suppress the inter-path interference (IPI) and the inter-code interference (ICI), resulting from the channel frequency-selectivity, and the interference from other antennas simultaneously. An iterative PIC with 2D MMSE-FDE has a high computational complexity. In this paper, to well suppress the interference from other antennas while reducing the computational complexity, we propose to replace 2D MMSE-FDE by 1D MMSE-FDE except for the initial iteration stage and to use multicode spread-spectrum (SS) transmission instead of the non-spread SC transmission. The BER performance of the proposed scheme in a frequency-selective Rayleigh fading channel is evaluated by computer simulation to show that the proposed scheme can basically match the BER performance of 2D MMSE-FDE with lower complexity.