A New Blind Beamforming and Hop-Timing Detection for FH Communications

Abdul Malik NAZARI  Yukihiro KAMIYA  Ko SHOJIMA  Kenta UMEBAYASHI  Yasuo SUZUKI  

Publication
IEICE TRANSACTIONS on Communications   Vol.E94-B   No.5   pp.1234-1242
Publication Date: 2011/05/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.1234
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Antenna and Propagation Technologies Contributing to Diversification of Wireless Technologies)
Category: Adaptive Array Antennas
Keyword: 
array signal processing,  constant modulus algorithm,  fading channel,  frequency hopping communications,  hop-timing,  

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Summary: 
Hop-timing detection is of extreme importance for the reception of frequency hopping (FH) signals. Any error in the hop-timing detection has a deleterious effect on the performance of the receiver in frequency hopping (FH) communication systems. However, it is not easy to detect the hop-timing under low signal to noise power ratio (SNR) environments. Adaptive array antennas (AAA) have been expected to improve the performance of FH communication systems by beamforming for the direction of arrival of the desired signal. Since the conventional AAA exploits at least the coarse synchronization for dehopping of FH signals before achieving the beamforming, any fault in the hop-timing detection causes the deterioration of the performance of AAA. Using AAA based on the constant modulus algorithm (CMA), this paper proposes a new method for blind beamforming and hop-timing detection for FH signals. The proposed method exploits both the spatial and temporal characteristics of the received signal to accomplish the beamforming and detect the hop-timing without knowing any a priori information such as fine/coarse time synchronization and training signal. The performance verifications of the proposed method based on pertinent simulations are presented.