METHOD FOR REMOTE INTERFERENCE DETECTION AND MITIGATION
A method of mitigating remote interference caused by an aggressor base station on a victim base station in an Open Radio Access Network (O-RAN) system includes: adjusting, by the aggressor base station, a time domain position of a first remote interference management reference signal (RIM-RS) transmission from the aggressor base station to the victim base station to ensure the transmitted RIM-RS arrives at the victim base station coincidentally with a sounding reference signal (SRS) received by the victim base station; deriving, by the victim base station based on the received first RIM-RS, an angle of arrival (AoA) of the RIM-RS received from the aggressor base station; forwarding, by the victim base station, the angle of arrival (AoA) value for the RIM-RS to a controller module; and adjusting, by the controller module, an angle of departure (AoD) of a second RIM-RS transmission from the aggressor base station.
1 . A method of mitigating remote interference caused by an aggressor base station on a victim base station in an Open Radio Access Network (O-RAN) system, comprising:
adjusting, by the aggressor base station, a time domain position of a first remote interference management reference signal (RIM-RS) transmission from the aggressor base station to the victim base station to ensure the transmitted RIM-RS arrives at the victim base station coincidentally with a sounding reference signal (SRS) symbol slot at the victim base station;
deriving, by the victim base station based on the received first RIM-RS, at least an angle of arrival (AoA) of the RIM-RS received from the aggressor base station;
forwarding, by the victim base station, the angle of arrival (AoA) value for the RIM-RS to a controller module; and
adjusting, by the controller module, an angle of departure (AoD) of a second RIM-RS transmission from the aggressor base station.
2 . The method according to claim 1 , further comprising:
deriving, by the victim base station based on the received first RIM-RS, at least a level of interference caused by the first RIM-RS received from the aggressor base station to the victim base station.
3 . The method according to claim 2 , wherein the controller module transmits a target AoD of the second RIM-RS to the aggressor base station, and the aggressor base station transmits the second RIM-RS at the target AoD to mitigate the remote interference caused by the aggressor base station.
4 . The method according to claim 3 , wherein the target AoD is implemented by the aggressor base station by applying a new set of beamforming weights to the RIM-RS signal to achieve a vertical angle corresponding to the target AoD.
5 . The method according to claim 2 , further comprising:
deriving, by the victim base station based on the received second RIM-RS, an AoA of, and a level of interference caused by, the second RIM-RS received from the aggressor base station;
forwarding, by the victim base station, the AoA value and the level of interference caused by the second RIM-RS to the controller module; and
determining, by the controller module, whether the level of interference caused by the second RIM-RS has reached a specified minimum level.
6 . The method according to claim 5 , further comprising:
in the case the level of interference caused by the second RIM-RS has reached the specified minimum level, informing the aggressor base station by the controller module of no further AoD adjustment.
7 . The method according to claim 5 , further comprising:
in the case the level of interference caused by the second RIM-RS has not reached the specified minimum level, adjusting by the controller module an AoD of a third RIM-RS transmission from the aggressor base station.
8 . The method according to claim 7 , wherein the controller module transmits a target AoD of the third RIM-RS to the aggressor base station, and the aggressor base station transmits the third RIM-RS at the target AoD to mitigate the remote interference caused by the aggressor base station.
9 . The method according to claim 7 , further comprising:
iteratively performing the steps of i) deriving, by the victim base station, an AoA of, and a level of interference caused by, each respective RIM-RS received from the aggressor base station, and ii) adjusting by the controller module an AoD of each subsequent RIM-RS transmission from the aggressor base station, until the level of interference caused by RIM-RS transmission reaches the specified minimum level.
10 . The method according to claim 7 , wherein the controller module is one of i) an operations, administration and maintenance (OAM) controller module, or ii) a radio access network intelligent controller (RIC).
11 . The method according to claim 6 , further comprising:
performing, by the aggressor base station based on the AoD of the second RIM-RS, a spatial interference mitigation including one of beam nulling or beam muting.
12 . The method according to claim 6 , further comprising:
performing, by the victim base station based on the AoA of the second RIM-RS, a spatial interference mitigation including one of beam nulling or beam muting.
13 . The method according to claim 11 , further comprising:
performing, by the victim base station based on the AoA of the second RIM-RS, a spatial interference mitigation including one of beam nulling or beam muting.
14 . The method according to claim 2 , wherein the adjusting of the time domain position of the first RIM-RS transmission from the aggressor base station to the victim base station is based on i) a propagation time of a previously transmitted RIM-RS preceding the first RIM-RS between the aggressor base station and the victim base station, and ii) the time domain position of the SRS symbol slot in the victim base station.
15 . The method according to claim 5 , wherein the adjusting of the time domain position of the first RIM-RS transmission from the aggressor base station to the victim base station is based on i) a propagation time of a previously transmitted RIM-RS preceding the first RIM-RS between the aggressor base station and the victim base station, and ii) the time domain position of the SRS symbol slot in the victim base station.