Experimental Evaluation of Space Diversity Schemes at a Base Station in a Microcellular Environment at 900 MHz and 1800 MHz

Abstract

The aim of this paper is to evaluate experimentallythe performance of different space diversity schemesat the base station end in a semi-urban microcellularenvironment. The receiving antennas were separated inhorizontal, vertical or compound direction in order toprovide decorrelated signals. The superior receivedsignal was chosen based on the selection combiningcriterion. A measurement campaign was conducted atboth appropriate frequency bands (900 MHz and 1800 MHz) for mobiletelecommunications. Measurements wereperformed along the route containing bothline-of-sight (LOS) and non-line-of-sight (NLOS)paths. The measured data was analyzed and signalcross-correlations, signal mean levels of individualreceiving branches and diversity gains of differentreceiving antenna separations (horizontal, verticaland compound) were evaluated. According to themeasurements, low signal cross-correlations andreasonable diversity gain at the base station end canbe achieved even with ≤4λ separation ofthe receiving antennas in any direction at both 900 MHz and 1800 MHz frequencybands. The obtained resultsalso showed that horizontal, vertical and compoundspace diversity gains are almost the same. Hence,spatially small and variable antenna configurationsfor space diversity reception can be applied at thewall installations in a microcellular environment.