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ABSTRACT: Equipment which has the capabilities of multipath measurement and
also for wideband (16 MHz) digital simulation of a land mobile radio
channel is described. Since the equipment has the capability for
reproducing measured multipath, the authors propose to use measured data
(successive impulse response sequences) to make a standard propagation
model. This can then be used as an alternative to the conventional
simplified model for developing and evaluating radio equipment operating
in the land mobile multipath environment. In the multipath measurement
mode, the equipment has the capability to store signals from multiple
receiving antennas. One can use three-dimensional antenna array on
vertical and horizontal polarizations simultaneously. Consequently, one
can measure arbitrary incoming path directions. This capability is
useful for developing and evaluating adaptive arrays and space diversity
antennas as countermeasures to channel distortion in the multipath
propagation environment
Vehicular Technology Conference, 1992, IEEE 42nd; 06/1992
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ABSTRACT: Experimental and calculated results of propagation characteristics
above 1 GHz for microcellular land mobile radio in an urban area are
described. Measurements were made at 1.5 GHz and 2.6 GHz with a fixed
antenna located at the side of the road at a height of 5.3 m. Data were
taken with an omnidirectional antenna at 2 cm intervals along the
measured routes. Tall buildings line the measured routes on both sides.
According to the experimental and calculated results, the propagation
loss is dominated by interference among the direct ray and specularly,
building-reflected and mobile-reflected rays in the line-of-sight
propagation environment, and by interference between specular rays and
building-diffracted rays in shadowed propagation. Therefore, in
line-of-sight propagation, the median of propagation loss is similar to
the free-space loss. In shadowed propagation, however, the median is not
determined only by the base-to-mobile antenna distance
Vehicular Technology Conference, 1990 IEEE 40th; 06/1990
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ABSTRACT: Urban measurements were carried out in the Tokyo metropolitan area
and rural measurements in the Hiraiso region. Radio propagation loss was
measured at 2 cm intervals along the measuring routes, and median
propagation losses in the three frequency bands was compared. In the
urban experiment, the influence of obstacles on median values of radio
propagation loss is almost the same in the three frequency bands except
for the constant propagation loss factor, which is different for each
frequency. The average difference in the median value of propagation
loss between the 1.5 GHz band and the 2.3 GHz band is about 5 dB, while
that between the 1.5 GHz band and the 2.6 GHz band is about 8 dB
Vehicular Technology Conference, 1989, IEEE 39th; 06/1989
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ABSTRACT: The authors consider practical approaches to multiple-access communication in spread-spectrum mobile radio. Efficient field test and data processing methods are given, and the field test results are described. Bit-error-rate (BER) performance with both one and four interferers is measured, with good agreement between field and laboratory results. In the single interferer case, the BER is 10<sup>-1 </sup> when a mobile transmitter located 350 m from the base station interferes with a mobile transmitter 3.5 km away. In the case of interferers, for DUR (desired-to-undesired signal ratio) of -20 dB, the BER approaches 10<sup>-2</sup>. The performance of synchronous code-division multiaccess (CDMA), in which the frame timing of hopping patterns among users is synchronized, is also measured. The improvement obtained by using synchronous CDMA amounts to 15 dB compared with the use of asynchronous CDMA
Electrotechnics, 1988. Conference Proceedings on Area Communication, EUROCON 88., 8th European Conference on; 07/1988
