A.104 Use case of UL remote interference identification

28.5523GPP5G performance measurementsManagement and orchestrationRelease 18TS

When atmospheric ducting phenomenon happens, radio signals can travel a relatively long distance, and the propagation delay goes beyond the gap. In this case, the downlink signals of an aggressor base station can travel a long distance and interfere with the uplink signals of a victim base station that is far away from the aggressor. Such interference is termed as ‘remote interference’. When it happens, the IoT of the victim base station demonstrates a "sloping" characteristic, the closer the uplink symbol is to gap, the higher interference it experienced. The reason behind this is that, the remote interference is caused by accumulated signals from a number of remote base stations with different distances.

This type of interference affects the effective reception of SRSs, resulting in a series of problems affecting user experience, such as call drops, access failures, and low rates. Therefore, some related measurements, such as GP symbol interference, SRS symbol interference and PUSCH symbol interference measurement, are needed to monitor/detect remote interference.