Decorrelation Performance of Spatial Smoothing Preprocessing at Transmitter in the Presence of Multipath Coherent Waves

Natsumi ENDO  Hiroyoshi YAMADA  Yoshio YAMAGUCHI  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.9   pp.2297-2302
Publication Date: 2007/09/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.9.2297
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on 2006 International Symposium on Antennas and Propagation)
Category: Smart Antennas
DOA estimation,  decorrelation preprocessing,  multipath,  spatial smoothing preprocessing,  

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Direction of arrival estimation of coherent multipath waves by using superresolution technique often requires decorrelation preprocessings. Spatial smoothing preprocessings are the most popular schemes as the techniques. In mobile environment, position change of the target/transmitter often brings us decorrelation effect. In addition, multiple signals transmitted by an antenna array, such as a MIMO transmitter, can also cause the same effect. These effects can be categorized as the spatial smoothing preprocessing at the transmitter. In this paper, we analyze the spatial smoothing effect at the transmitter in the presence of multipath coherent waves. Theoretical and simulation results show that the spatial smoothing at the transmitter has a good feature in comparison with the conventional SSP at the receiving array. We also show that better decorrelation performance can be obtained when the SSPs at the transmitter and receiving array are applied simultaneously.