| Summary: | 碩士 === 國立交通大學 === 電信研究所 === 83 === An adaptive beam pattern diversity scheme for reducing the
fading effects in a mobile environment is presented. The main
concept of the proposed diversity technique is to form two
reception beams encompassing the incoming fading signals. The
optimum beamformers are then constructed so as to minimize the
crosscorrelation coefficient between two beam outputs. The
beam patterns should possess low sidelobes for interference
rejection and mutual symmetry for equal power diversity
signals. To maintain an accurate look direction, a
localization method is also proposed. First, the source angle
estimate is obtained by comparing two sets of fixed Chebyshev
beams for equal output power. Second, range estimation is
accomplished by training a curve fitting unit (CFU) with the
data emitted from different subcells in the field of interest.
The CFU is constructed to memorize the relationship among
various incoming angles, ranges, and the corresponding squared
magnitudes of beam space crosscorrelation coefficients
(BSCCC). Specifically,it is used as a mapping from the squared
magnitude of BSCCC to the range estimate. We demonstrate that
the proposed adaptive beam patten diversity scheme working in
conjunction with the location estimator provides an appropriate
solution for fading phenomenon in the presence of complicated
interference.
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