Accurate Source Number Detection Using Pre-Estimated Signal Subspace

Yoshihisa ISHIKAWA
Hiroyuki ARAI

IEICE TRANSACTIONS on Communications   Vol.E89-B    No.12    pp.3257-3265
Publication Date: 2006/12/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.12.3257
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Software Defined Radio Technology and Its Applications)
source number detection,  array antenna,  AIC,  MDL,  MUSIC method,  beamformer method,  

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This paper presents a scheme for accurately detecting the number of incident waves arriving at array antennas. The array antenna and MIMO techniques are developing as 4th generation mobile communication systems and wireless LAN technologies, and the accurate estimation of the propagation environment is becoming more important. This paper emphasizes the accurate detection of the number of incident waves; one of the important characteristics in multidirectional communication. There are some recent papers on accurate detection but they have problems of estimation accuracy or computational cost in severe environment like low SNR, small number of snapshots or waves with close angles. Hence, AIC and MDL methods based on statistics and information theory are still often used. In this paper, we propose an accurate estimation method of the number of arrival signals using the orthogonality of subspaces derived from preliminary estimation of signal subspace. The proposed method accurately estimates the number of signals also in severe environments where AIC and MDL methods can hardly estimate. We evaluate the performance of these methods through some computer simulation and experiments in anechoic chamber.