I’ve came across some articles about ICC, UISS and SIAC too. These are some features used to realize the DFCA function on GSM. It’s suppose to synchronize (either using GPS or software clock generator) the time frames of each BTS under one BSC in pairs and in a circular order. A pair would require around 5 mins to sync, as it needs to collect enough MRs and has to be processed at the BSC end. During information collection process, some signaling channels would be taken up.
All these functions are suppose to reduce interference and/or use as an anti interference technology.
I’m not sure if the technology has been deployed anywhere in the world yet. Do keep me inform if you have any information regarding DFCA.