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The aim of this paper is to evaluate experimentally the relationships between cross-polarization discrimination (XPD), signal cross correlation, and polarization diversity gain with horizontally/vertically (HV) polarized reception at the base-station (BS) end at 1800 MHz. The performance of the horizontal/vertical polarization diversity scheme was also compared with a diversity scheme with 645 slanted polarizations and horizontal space diversity at 1800 MHz in a personal communication system (PCS) mobile network. A measurement campaign was conducted in small/micro cells in different types of areas, taking into account the influence of mobile antenna inclination. According to the measurements, XPD values for horizontal/vertical polarizations vary between 5-15 dB, depending on the environment. Furthermore, XPD values depend highly on the radio propagation path between the BS and mobile station (MS) due to line-of-sight (LOS) and nonline-of-sight (NLOS) situations. Signal cross correlations of horizontal and vertical polarizations in both LOS and NLOS situations were clearly below 0.7, which is the generally accepted value to have a reasonable improvement at the receiving end with diversity. Finally, the results showed that almost equal diversity gain and system performance in a PCS network at 1800 MHz can be achieved in small/micro cells in different environments with 645 slanted polarizations at the BS end when comparing results with horizontal space diversity. The performance of horizontal/vertical polarization diversity scheme was approximately 1 dB worse than horizontal space diversity.

Absfrucf-The aim of this paper is to evaluate the impact of the base station mechanical antenna downtilt scheme on the downlink capacity of a 6-sectored WCDMA cellular network of 33" horizontal beamwidth antennas. The etTect of the base station antenna height and vertical beamwidth together with site spacing was evaluated in a macrocellular environment and observations were made based on system level simulations utilizing a Monte Carlo approach. The results show that downlink capacity of a WCDMA cellular network obviously depends on the mechanical downtilt angle and the capacity enhancements are based on reduction o f other-cell interference. Moreover, the soft and softer handover areas are changed according to mechanical downtilt angle, which clearly depends on the base station antenna height and vertical heamwidth together with site spacing.

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A data-mining framework for analyzing a cellular network drive testing database is described in this paper. The presented method is designed to detect sleeping base stations, network outage, and change of the dominance areas in a cognitive and self-organizing manner. The essence of the method is to find similarities between periodical network measurements and previously known outage data. For this purpose, diffusion maps dimensionality reduction and nearest neighbor data classification methods are utilized. The method is cognitive because it requires training data for the outage detection. In addition, the method is autonomous because it uses minimization of drive testing (MDT) functionality to gather the training and testing data. Motivation of classifying MDT measurement reports to periodical, handover, and outage categories is to detect areas where periodical reports start to become similar to the outage samples. Moreover, these areas are associated with estimated dominance areas to detected sleeping base stations. In the studied verification case, measurement classification results in an increase of the amount of samples which can be used for detection of performance degradations, and consequently, makes the outage detection faster and more reliable.