The best graphic demo of the three types of 5G interference, and a comparison of the viability of two types of band-pass filter solutions.

Satellite telecommunication has advantages of broad coverage, high efficiency, and high availability, it has been widely used in telecommunication and TV broadcasting. In recent years, along with the cellular 5G deployment, satellite signals are severely interfered by 5G since they are operating in adjacent frequencies.

This is a typical satellite TVRO system, the antenna receives the signal from the satellite, then the receiver (IRD) amplifies the signal, decodes it and send to TV.

We test to receive the 3740V TV channel from APSTAR-7 satellite. Normally the TV and spectrum is clear of any interference.

After a 5G base station is deployed in the nearby facility, the TV reception becomes abnormal. The spectrum analyzer shows a cluster of jumping carriers nearby our target TV signal, it is the 5G carrier who causes the problem.

There are three types of 5G interference. Type 1: Co-frequency interference. The 5G operates in the same frequency as the satellite in the 3.4-3.6GHz band. With over thousands of times of power magnitude, 5G totally overwhelms the satellite in this band. Type 2: Spurious interference. Some 5G equipment emits spurious carriers outside of its working frequency bands, interfering into the satellite in 3.7-4.2GHz band. Type 3: Saturation interference. Although in difference frequency band, the 5G is so powerful that it still manages to drive the LNB amplifiers to saturation point, then satellite TVRO stops working.

To solve the problem, we should stop the 5G signals from entering into the satellite receiving system. 5G operates in 3.4-3.6GHz band, satellite operates in 3.4-4.2GHz band. By installing a band-pass-filter in front of the LNB, we can filter off the 5G signal, only reserves the satellite signals in 3.7-4.2GHz band.

It is important to note that the 5G frequency used by local mobile operators are different in many regions, the model of the band-pass-filter should also vary. These are two typical models, the one in the left is upgraded to eliminate very serious 5G interference, it is suitable for situation where 5G base station is very close-by, or the frequency of the target satellite signal is close to 5G‘s. Its high performance comes with a compromise on its insertion loss, which decreases the satellite link margin by 1.5 dB. The right one is more commonly used in general situations, it performs decently with relatively low costs.

Once caught in 5G interference, satellite users should investigate the nearby 5G base station deployment, and its working frequencies, so as to come up with an appropriate band-pass-filter solution.