No abstract

No abstract

No abstract

For the sake of new radio devices to conform to respective standards, implementing functionality such as cognitive radio, Long Term Evolution beyond 2x2, or Global Navigation Satellite Systems, a demand for extensive testing arises. A promising solution is the validation inside an Over-the-Air testbed that creates a virtual electromagnetic environment using wave-field synthesis. This paper analyzes the polarimetric accuracy of a wave field generated by a hemispheric (3D) antenna arrangement. As most radio devices have a flat shape (e. g. smart phones, tablets, compact cognitive radio antennas) or a metallic backplane along a defined surface, the complexity of the optimization problem can be reduced. Analyzing the wave-field synthesis accuracy, it has to be kept in mind that for most radio devices the signal-to-noise ratio is limited in a range between 0-30 dB, which indirectly defines the upper limits of the required wave-field synthesis accuracy

The quality of service of mobile satellite reception can be improved by using multi-satellite diversity (angle diversity). The recently finalised MiLADY project targeted therefore on the evaluation and modelling of the multi-satellite propagation channel for land mobile users with focus on broadcasting applications. The narrowband model combines the parameters from two measurement campaigns: In the U.S. the power levels of the Satellite Digital Audio Radio Services were recorded with a high sample rate to analyse fast and slow fading effects in great detail. In a complementary campaign signals of Global Navigation Satellite Systems (GNSS) were analysed to obtain information about the slow fading correlation for almost any satellite constellation. The new channel model can be used to generate time series for various satellite constellations in different environments. This article focuses on realistic state sequence modelling for angle diversity, confining on two satellites. For this purpose, different state modelling methods providing a joint generation of the states 'good good', 'good bad', 'bad good' and 'bad bad' are compared. Measurements and re-simulated data are analysed for various elevation combinations and azimuth separations in terms of the state probabilities, state duration statistics, and correlation coefficients. The finally proposed state model is based on semi-Markov chains assuming a log-normal state duration distribution.