Passive Intermodulation Mitigation (PIM)
The usage of low and high bands in cellular networks exposes network performance to the passive inter-modulation between these bands causing interference and performance degradation. Passive inter-modulation could be caused by an internal imperfection within the transmission system such as a bad connector or bad antenna. It also could be caused by an external cause such as an old metal ladder or wrong stealth material.
To address efficiently, investigate and mitigate PIM issues, RF performance engineers, OSS experts, field crews, and project managers teamed up to closely look and resolve the issues. Typical project flow as following:
- Study spectrum to determine potential PIM frequencies
- Establish KPIs screening criteria to shortlist sites with potential PIM issues
- Audit site parameters that is directly related to PIM
- Send crews to shortlisted sites to determine if PIM is internal or external
- Rectify internal PIM issues in the field and use PIM testers and OSS to clear the site
- If external PIM, perform external PIM hunting using proper equipment
- Track fixed sites to confirm KPIs compliance
