| Summary: | 碩士 === 國立臺灣海洋大學 === 導航與通訊系 === 93 === This study investigates the MISO, one of the special case of MIMO, the statistical analysis for the multiple transmit antenna array with various antenna spacing, d in an indoor LOS light clutter gymnasium. There is no intention to evaluate the system performance either beamforming array antenna or spatial division antenna, but focus on the statistical distribution of the signal strength and time delay spread based on the measurement data in the indoor Line-of-Sight environment. For wireless communications, the difference between beamforming and spatial division of the down-link is dependent on:
(1) Mutually independent or fully correlated amongst antennas over multipath fading channel.
(2) The systems performance effectively contributed by Array Gain or Diversity Gain.
(3) Antenna spacing vs. channel correlation and delay spread.
The MS was moved along a specified line over a distance 5m( 30λ) using 1.87GHz carrier frequency. The BS consists of 5 uniform linear array dipole antennas. The correlation matrix and delay spread are derived based on measurement data. The maximum-to-minimum-eigenvalue-ratio value (MMEVR) and its standard deviation of eigenvalues are also calculated to validate which indicates λ/2 spacing has better performance in terms of the signal strength (higher eigenvalue) and low delay spread, our results than those with spacing λ/2. It is also concluded that both parameters do not make difference for antenna spacing larger than λ/2 under LOS light clutter indoor radio propagation. From our analysis, it indicates that has the better orthogonal channel (i.e. better S/N) that is suitable for spatial division in a MIMO system, while its standard variation of these eigenvalues indicates larger than others. Meanwhile the loss of orthogonal channel (partially correlated) is also existed.
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