RF Interference - Practical Perspective

RF engineers would be able to reach plenty of online resources & technical references explaining each type of interference source and how we can mitigate its impact on our legacy networks or the 5G NR network, especially with 5G which is still on our learning curve coming with multiple unknowns. Let's define the different types of interference sources as follows,

1- Internal Interference: this basically results from the consequences of improper network installation, inaccurate antenna alignment, faulty RF components or wrong sector/frame configuration during the commissioning/optimization phase (to be addressed later in next articles). PIM (Passive Intermodulation) represents the worst consequence of either low-rated PIM or faulty components installed on the mobile tower, typically, this issue can be easily discovered using the built-in PIM detection tool of your spectrum analyzer.

2- External Interference: this type of interference represents more than 70% of network performance issues, and the mobile operator starts recognizing this issue only upon receiving multiple complaints from their subscribers or from their back-office performance counters. The external source of interference could be home repeaters, jammers, or other networks operating at the same frequency/range.

For quick & accurate interference detection, suspicious/candidate areas of interference, network performance error/indicator (i.e. RTWP, ..etc), and the highly impacted frequency range or channel frequencies have to be identified. What else do you think is required to start hunting for your interference source?

The ultimate goal of interference hunting campaign is always to characterize the interference pattern and identify the interferer's location. Do you think a traditional spectrum analyzer (swept-tuned analyzer) would be enough for this mission? Does it require an RTSA (Real-time Spectrum Analyzer)? does it depend on the expertise of your RF engineer? do you think a waterfall (spectrogram) function would help in identifying the instantaneous (rapidly-changing) interference sources?