Optimal Signal Combining Based on DOA and Angular Spread Using Extended Array Mode Vector

Jung-Sik JEONG
Jun-ichi TAKADA
Kiyomichi ARAKI

IEICE TRANSACTIONS on Communications   Vol.E84-B    No.11    pp.3023-3032
Publication Date: 2001/11/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Antenna and Propagation
DCMP,  zero-forcing,  signal copy,  optimal beamforming,  angular spread,  

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This paper presents the performance of the Directionally Constrained Minimization of Power (DCMP) and the Zero-Forcing (ZF) in the Angular Spread (AS) environment. To obtain the optimal weights for both methods, the Extended Array Mode Vector (EAMV) is employed. It is known that the EAMV represents the instantaneous AS as well as the instantaneous DOA in the slow fading channel. As a result, it is shown that the DCMP and the ZF using the EAMV estimates can improve the Signal-to-Interference-plus-Noise Ratio (SINR) considerably, as compared with those using the Direction of Arrival (DOA) information only. At the same time, the intrinsic problems causing the performance loss in the DCMP and the ZF are revisited. From this, the reasons for the performance deterioration are analyzed, in relation with the AS, the number of samples, the number of antenna elements, and the spatial correlation coefficient of the signals. It follows that the optimal signal combining techniques using the EAMV estimates can diminish such effects.