Contribution to the millimeter-wave propagation characterization for satellite and 5g wireless links

Resumo

The future spectral saturation in the SHF band in satellite systems, together with the crowding of the currently used bands and the increasing demand of high-speed data transfer in wireless communication systems have led to consider millimeter-wave frequencies (from 10 to 300 GHz) for allocating new applications both for satellite and terrestrial systems. The objective of this research is to contribute in the characterization and modeling of the millimeter-wave propagation channel —specifically for satellite links in the Ka and Q/V bands and in indoor wireless links at frequencies (26 and 39 GHz) that will be used in the future 5G systems— by collecting, processing and analyzing experimental propagation channel data. This objective is convenient since the channel propagation for these systems has not been fully characterized. For satellite propagation analyzes, data with a high availability have been used: 5 years of measurements of the KA-SAT satellite beacon in the Ka-band and 4 years of measurements of the Alphasat satellite Q-band beacon, together with ancillary meteorological information. Relevant contributions have been obtained regarding fade dynamics −fade (FD) and inter-fade (IFD) duration−, diversity techniques −time (TD) and orbital (OD) diversity− and the variability of statistics (rainfall rate, excess attenuation and fade dynamics), issues that have not been thoroughly treated in previous works. Regarding FD and IFD, a modeling effort has been carried out with several function combinations. The two log-normal function is the best option to model the FD probability of occurrence and fraction of time distributions. Also, it was concluded that this function can be used for fitting the IFD probability of occurrence and inter-fading time distributions for durations shorter than 10^6 s (for higher durations, a third function must be used). The possible TD gains have been derived and compared with four models (Matricciani TD, ONERA, Greece and Joint Probability). From that, comparably good results have been obtained. The OD results were derived after a frequency scaling procedure and two models (Matricciani OD and NTUA) have been tested. It was found that in the Q-band TD gain with a delay ranging from 3 to 5 minutes may emulate the OD gain with the available angular separation (18.1°), allowing a complementary use between these techniques. The millimeter-wave indoor experimental equipment was set up and calibrated. This and the data processing of the measurements have been treated thoroughly. Two kinds of measurements were gathered: path loss and MIMO (Multiple Input Multiple Output), both at line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. Path loss measurements were taken in a corridor scenario with two sets of antennas: horns and omnidirectional. These results were fitted with several functions, and the obtained coefficients compared with models specifically developed for millimeter-wave (such as the METIS, the 3GPP TR 38.901, the 5GCM, the mmMAGIC and the ITU-R Rec. P.1238-9), showing similarities in some cases. The expected waveguide-like propagation effect for LOS condition and a higher path loss in NLOS than in free space have been obtained. MIMO measurements have been gathered at 39 GHz with a 2×2 omnidirectional antennas setup, and the channel capacity has been tested using the condition number of the channel matrices .