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The aim of this paper is to present the results of a measurement campaign focused on the evaluation of penetration loss into buildings in an urban area as a function of the elevation angle. An empirical model to predict penetration loss into buildings is developed based on measured data obtained using a remote-controlled airship. The impact on penetration loss of different buildings and user positions within the buildings is presented. The measured data are evaluated as a function of the elevation angle. The measurement campaign was carried out at 2.0 GHz and 3.5 GHz carrier frequencies, representing the frequency band for high altitude platform third-generation mobile systems and, potentially, next generation mobile systems, mobile WiMAX, for example, the new penetration loss model can be used for system performance simulations and coverage planning.

An investigation into the impact of antenna radiationpatterns on the performance of a 3G mobile communication system provided a single high-altitude platform (HAP) is presented. Use of elliptical and circular beam antennas is examined for a 91-cell system. Crucial performance parameters are shown to be the mainlobe power roll-off and sidelobe level. It is presented that the optimum power roll-off from cell center to the cell edge ranges between 10-35 dB, which is dependent on the types of antennas used, sidelobe level, and antenna gain strategy employed. Elliptical beam antennas are proven to provide the best solution, but circular beam antennas with their gain adjusted to reduce the degree of cell overlap and compensate for increasing path loss are shown to provide similar performance, with the advantage that they are practically more realizable. It is shown that poorer overlap performance can be partially compensated for by an increased power roll-off at the cell edge, a strategy that is employed in the case of the gain adjusted circular beam antennas.The impact of cell radius and elevation angles is also assessed.

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