Institute for Telecommunication Sciences
the research laboratory of the National Telecommunications and Information Administration

Michael G. Cotton; Robert J. Achatz; Yeh Lo; Christopher L. Holloway

Abstract: This report investigates how antenna polarization and directivity affect indoor radio channel bandwidth and signal coverage. Indoor impulse response measurements were taken at 5.8 GHz for four canonical propagation conditions: within a room, down a corridor, from a corridor into a room, and around a corridor corner. Directional linearly-polarized (LP), directional circularly-polarized (CP), and omnidirectional LP antennas were employed, and conclusions were drawn from basic transmission loss, rms delay spread, and cross-polarization discrimination results. Measurements indicated less LP basic transmission loss than CP basic transmission loss for both line-of-sight (LOS) and obstructed (OBS) channels. Also, LP rms delay spread was similar to CP rms delay spread in both LOS and OBS paths. The apparent advantage of using LP signals over CP signals indoors may be attributed to the relatively high degree of circular depolarization measured. Results also supported the use of omnidirectional antennas indoors to improve signal coverage. Omnidirectional measurements, however, demonstrated large delay spreads for some extraneous cases. These cases are emphasized to demonstrate the potential diversity holds for improving bandwidth capacity of indoor communication systems.

Keywords: basic transmission loss; polarization; delay spread; complex impulse response measurements; indoor propagation; cross-polarization discrimination; antenna directivity


To request a reprint of this report, contact:

Lilli Segre, Publications Officer
Institute for Telecommunication Sciences
(303) 497-3572
lsegre@ntia.doc.gov

For technical information concerning this report, contact:

Michael G. Cotton
Institute for Telecommunication Sciences
(303) 497-7346
mcotton@ntia.doc.gov


Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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