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Wide-band SIMO 1/spl times/2 measurements and characterization of outdoor wireless channels at 1.9 GHz | IEEE Journals & Magazine | IEEE Xplore

Wide-band SIMO 1/spl times/2 measurements and characterization of outdoor wireless channels at 1.9 GHz

Publisher: IEEE

Abstract:

This paper aims at characterizing the spatial wireless channel at 1.9 GHz, based on a 1/spl times/2 measurement chain. A typical campus/residential area and an industrial...View more

Abstract:

This paper aims at characterizing the spatial wireless channel at 1.9 GHz, based on a 1/spl times/2 measurement chain. A typical campus/residential area and an industrial area have been investigated. The measurement equipment is constituted by an 80-MHz transmitter at 1.9 GHz, located at the top of a building. At the receiver, two omnidirectional antennas are connected to a wide-band channel sounder through a switch in order to measure an estimate of the instantaneous vector channel. It is found that the Ricean K-factor and the delay spread are lognormally distributed, while the azimuth spread at the receive side follows a Gaussian distribution. The range dependence of various parameters are pointed out and compared with empirical models. The impacts of antenna spacing and array orientation on the channel correlation are highlighted and compared to theoretical simulation results. Finally, the cross-correlation properties between K-factor, delay spread, azimuth spread, and channel correlation are analyzed.
Published in: IEEE Transactions on Vehicular Technology ( Volume: 53, Issue: 4, July 2004)
Page(s): 1190 - 1202
Date of Publication: 26 July 2004

ISSN Information:

Publisher: IEEE

I. Introduction

In THE last years, there has been a renewed interest for modeling the spatial wireless channel in the framework of multiple-input multiple-output (MIMO) broad-band wireless communication systems. MIMO systems combine the use of antenna arrays at both the base station (BS) and the subscriber end with space–time signal-processing techniques in order to improve the link quality or increase the system capacity. A common assumption in the study of such systems is to consider the fading channels between pairs of transmit and receive antennas as independent identically Rayleigh distributed (Rayleigh i.i.d.). In practice, fading channels might not be Rayleigh distributed due to the existence of a dominant component. Also, channels as seen by different antennas are often correlated, depending on the antenna spacings and polarizations, the possible existence of mutual coupling, the richness of scattering, etc. Fading correlation is shown in [1] and [2] to have a significant impact on the capacity and performance of MIMO systems. A number of recent papers have presented measurement results regarding directional and MIMO channels [3]– [6], each focusing on different aspects. In [3], empirical results characterizing the joint statistical properties of azimuth spread at the BS, delay spread, and shadow fading are analyzed in various environments, using the space-alternating generalized expectation (SAGE) maximization algorithm. In [4], measurements of the directional wide-band channel in downtown Helsinki are reported. Multipaths at the BS are resolved in both space and angle by means of the Unitary ESPRIT algorithm. In [5], azimuth-delay profiles at the BS have been recorded in Japan, by means of a wide-band sounder, together with a rotating receive antenna. In [6], empirical results for fixed macrocellular wireless local area networks (WLANs) are described, with a highlight on the range-dependence behavior of the channel parameters. Regarding the microcellular channel, usual measurements do not simultaneously highlight range-dependent behaviors and link the channel correlation to propagation parameters such as the Ricean K-factor, azimuth, and delay spreads. Finally, most are narrow-band measurements.

References

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