Apparatus for processing passive intermodulation products

An apparatus for a communication system, the communication system comprising transmitters being configured to operate in multiple transmission frequency bands, the apparatus comprising:

• at least one processor;
• and
• at least one memory including computer program code, the at least one memory and computer program code being configured, with the at least one processor, to cause the apparatus to perform:
• capturing a set of over-the-air signals at distinct frequency bands of the multiple transmission frequency bands;
• aligning in time the set of signals using delays between the set of signals and a received signal at a selected receiver of the communication system;
• and
• combining the set of aligned signals to generate a composite signal;
• estimating an interference signal that is caused by the set of signals at the selected receiver by weighting the composite signal using a set of one or more calibrated parameters for the estimation.