SMI Adaptive Beamforming Based on Frequency-to-Time Pilot Transform for OFDM System

Ming LEI  Hiroshi HARADA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E89-B   No.8   pp.2261-2265
Publication Date: 2006/08/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.8.2261
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
Keyword: 
OFDM,  adaptive antenna array,  sample matrix inverse (SMI),  adaptive beamforming,  

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Summary: 
We propose an adaptive beamforming scheme for the combination of orthogonal frequency division multiplexing (OFDM) and adaptive antenna array. The combinational scheme is characterized by the sample matrix inverse (SMI) algorithm, frequency-to-time pilot transform and pre-FFT combination. For every OFDM block containing both data and pilot symbols, we transform the frequency-domain pilot symbols to the corresponding time-domain components. One of the obvious advantages of this transform is that the time interval of the antenna weight vector update can be reduced to only one OFDM sample interval, from one OFDM block interval of the conventional beamforming scheme in which the transform is not applied. This feature can greatly accelerate the convergence of SMI beamforming. The simulation results verify that the proposed beamforming scheme is capable of improving the convergence behavior significantly.