The Research Of LTE-Hotspot-Indoor Coexist With Fixed Satellite Service In The3.4-3.6GHz Band

As the development of communication technology, the service of the data traffic is growing explosively. According to the survey,70%of the data traffic is carried out in the buildings and at the hotspots areas. In order to improve the quality of the data service in such areas mentioned above, the LTE indoor hotspot enhancement system (LTE-Hi) is designed and assigned to the frequency band of3.5GHz. However, the band between3.4GHz and3.6GHz is an important part of the extended C-band, which is allotted to the fixed-satellite service (FSS) in our country. Thus the radio mutual interferences may happen between LTE-Hi and FSS. The method of setting protection distance to mitigate the interferences is proposed in this thesis supported by the Important National Science&Technology Specific Projects "Research of Hot spot enhancement technology and standard based on LTE’The theoretical calculation, simulation and filed test are studied in the thesis. The required protection distance for co-channel and adj-channel interferences is analyzed under the different scenarios, such as different transmit power and different off-axis angles.Firstly, the interference model is established and the necessary protection distance in theory is calculated for the FSS and LTE-Hi. Several radio propagation models are studied. We select the appropriate one for LTE-Hi and FSS. The in-band interference power threshold is calculated by the interference protection criteria. Then, the distance is set under the condition that the interference power is equal to the in-band interference power threshold. It is obvious that such distance is the necessary protection distance. Secondly, the Monte Carlo simulation analysis is carried out. The protection distance is increased by the step of50m and the averaged isolation under each protection distance is calculated. The relation curve between isolation and protection distance is plotted. Finally, a field test on the FSS earth station of the ChinaSat-11, ApStar-7interfered by LTE-Hi systems is completed at the Harbin station of State Radio Monitoring Center. The power threshold of the transmitter is searched under the condition that the locations of the two systems are fixed. Then the protection distance from LTE-Hi to FSS is calculated. The recommendations of interference protection are proposed at the last part of the thesis based on the theoretical calculation, simulation analysis and field test.The protection distance studied in the thesis is meaningful to the coexistence between FSS and LTE-Hi for sharing3.4-3.6GHz band and also important to the deployment of LTE-Hi base stations in the future by providing the constraints.