| Abstract [eng] |
Within less than 10 years since 4G technology has started, there is already a demand for high data traffic in many spheres of industry and casual life. The load of the mobile network is growing every year in Lithuania and other countries. This problem could be overcome with implementation of new 5G network technology, which could provide communications with much higher data transfer speed and applications in many industrial spheres as well. The pioneer frequency bands in EU are 700 MHz, 3500 MHz and 26 GHz where no mobile networks were used before. It is still a task to implement these bands with existing networks and minimal interference with non-EU countries that use these bands for different purposes. The aim of this work is to overview all three pioneer frequency bands designed for 5G communication to be established in EU by analyzing implementation on mobile connectivity and compatibility with already used communication networks in Lithuania and evaluating the prospects of 5G technology installation in the region. The main conclusions of this work are: 1. Theoretical and experimental results on the 700 MHz band have shown that there is high level of harmful interference in 713-718 MHz band because of neighbouring non-EU countries terrestrial television use, therefore the IMT network cannot be used in the region. With bands of 718-723 MHz and 720.5-725.5 MHz the interference levels are lower so the 5G network could be established, however due to television use on band 770 MHz, the power of these antennas should be lowered but with loss of servicing zone. So, the implementation of 5G in Lithuania in 700 MHz band is very complicated if terrestrial television is still in use. 2. Even though theoretical calculations show that IMT base stations should work when C/(I+N) ration positive, the experimental results on 700 MHz band show that signals from the network are not recognized if I is above -100 dBm. This can be concluded that in zones of high level interference there is high disagreement between experiment and theoretical results. 3. On radio frequency band of 3500 MHz the theoretical and experimental results best coincide when using P.2001 recommendation and 10% time probability. The worst results are obtained when using P.1546 recommendation and 10% time probability. 4. Theoretical calculations on 3500 MHz band show that the establishing of mobile network in Lithuania is not likely possible without common agreement with Russia – according to calculations on ITU-R P.452 propagation model, due to high levels of interference the closest mobile stations must be further than 170 km away from Russia border. Based on long term interference method the distortion in terrestrial station was 26 dB higher than allowed, and in short term - 50,8 dB than allowed. The only possibility of 5G network use could be fixed service stations. 5. Based on international agreements on 26 GHz band in Lithuania, harmful interference appears in 60 km zone from the border. Synchronisation could solve this problem. |
