Research On Co-channel Interference Mechanism Analysis In Integrated Satellite-5G Networks

The integration of the satellite-5G network can not only provide users with highbandwidth,low-latency,and wide-coverage services.As a supplement to 5G network,Satellite communications can provide many cost-effective solutions.But due to the scarcity of spectrum resources,5G cellular network reuses part of the frequency band of the satellite system.This will lead to inevitable co-frequency link interference problems when sharing spectrum between systems.Therefore,it is essential to adopt appropriate interference management solutions.In this paper,related researches are conducted on the co-frequency interference mechanism in integrated satellite-5G networks.First of all,this paper divides the integrated satellite-5G network architecture into direct access integrated network architecture and indirect access integrated network architecture according to the 3GPP definition of non-terrestrial networks.Based on the analysis of the shared frequency band between the satellite system and the 5G system,the co-frequency link interference of the two network architectures and the propagation mechanism of the interference signal are discussed.Through the deterministic analysis and calculation of the interference signal link,it is clear that the main interference links in the direct access network architecture and the indirect access network architecture are respectively: the interference of the terrestrial 5G base station to the satellite user and the interference of the terrestrial 5G base station to the satellite relay base station.Secondly,aiming at the main interference link between the satellite system and 5G system in the indirect 3GPP access network,this paper proposes the interference mechanism analysis scheme based on the protection zone and the directional antenna design.According to the requirements of the interference to noise ratio of the signals received by the satellite relay base station,the required protection distance between the5 G base station and the satellite relay base station of the satellite is obtained through relevant mathematical analysis and formula derivation.In addition,in order to further study interference between satellite system and terrestrial system,a directional design of the satellite relay base station antenna is carried out on the basis of the space protection distance,and the mathematical method of a random geometric frame is used to analyze the influence of the antenna elevation angle on the probability of normal communication when the satellite relay base station meets the signal interference and noise ratio requirements.Finally,aiming at the main interference link between the satellite system and 5G system in the direct 3GPP access network,this paper proposes the interference mechanism analysis scheme based on the game theory of beamforming and power control.By considering satellite users to feed back channel state information to the terrestrial base station,the terrestrial base station performs beamforming and power control after obtaining the downlink channel state information,and reduces interference to satellite users by adjusting the beamforming vector and transmit power.In order to obtain the best power control strategy and beamforming vector,the game theory method is adopted to optimize the transmit power of the ground base station.While ensuring the quality of service for terrestrial users,it minimizes the interference received by satellite users and at the same time meets the interference threshold requirements of satellite users.However,due to the limited bandwidth of the feedback channel of the base station,all game participants,that is,all users,need to compete for limited channel resources to increase their system capacity.Therefore,to solve this problem,a method of joint power control and feedback rate control is proposed.