The Interference Mitigation Method and Field Test in C-Band Between 5G System and FSS Receiver

Abstract

C-band is the most used frequency resource for the 5G development in the worldwide. However, fixed satellite service (FSS) is also deployed in this frequency band in many countries, which will suffer adjacent channel interference from 5G. In this article, we evaluate the interference in the real network deployed by China Unicom. The interference level is determined by network deployment parameters such as the load level of the 5G gNB, the location of the 5G terminals, and the angle between the gNB and the FSS antenna. To avoid the interference, the isolation between satellite and 5G should be improved by increasing the distance or the performance of transceiver. On the other hand, we also need to ensure the flexibility of 5G network deployment. Thus, the method that adding a filter to the FSS receiver is proposed. We test the suitable passband of the filter in the lab environment and verify the effective of this method under the most serious interference in the practical network. Tests have shown that when the filter has 45 dB suppression in the 5G frequency band, the isolation distance can be reduced to 90 m. Therefore, in the actual 5G network environment, the isolation distance between the 5G gNB and the FSS earth station can be further reduced, and a large number of 5G network coverage holes will be avoided.