A RAN engineer asked me for an Excel macro to visualize per-PRB interference counters.
The request sounded simple: load a file and draw a heatmap. But the chart was not the hard part. The hard part was making the result repeatable and technically honest.
So I built a small free browser tool instead.
273 PRBs is one configuration, not a rule
It is tempting to create 273 fixed columns because that is a familiar NR case. But the PRB count depends on bandwidth and subcarrier spacing. Real exports can also contain partial or non-continuous ranges.
The parser detects the PRB indices present in the file. The heatmap keeps every value, fits the complete range to the screen by default, and displays selected tick labels only. Exact values remain available on hover.
dBm values need power-domain averaging
An arithmetic mean is correct for many raw counters. It is not physically correct for power expressed in dBm.
For dBm values I use:
mean_dBm = 10 * log10(mean(10^(value_dBm / 10)))
For example, the arithmetic mean of -100 dBm and -110 dBm is -105 dBm. The power-domain mean is about -102.6 dBm. That difference matters when engineers compare PRBs or apply thresholds.
The tool therefore asks for the unit and whether higher or lower values represent more interference. It does not label a PRB as good or bad without an explicit threshold and counter meaning.
OSS exports do not all look the same
The importer supports:
- Wide rows such as
timestamp, cell_id, PRB_0, PRB_1, ... - Long rows such as
timestamp, cell_id, prb, interference - Single snapshots without a timestamp
- CSV separators using comma, semicolon, or tab
- XLSX worksheets and several cells
Automatic detection is useful, but the user can always correct the column mapping before analysis.
The privacy boundary should be visible
Network counter exports can contain sensitive identifiers. Parsing runs in a Web Worker, directly in the browser. The tool does not upload imported content, filenames, cell IDs, headers, or values.
The repository includes synthetic demo files, unit tests, end-to-end tests, and a network privacy test with unique sentinels. No real customer or vendor export is included.
Why make a dedicated tool?
A one-off chart can look convincing and still hide wrong assumptions. A reusable engineering tool gives the same parser, unit rules, calculations, limits, and exports every time.
You can try the tool without an account:
Open the 5G NR PRB Interference Visualizer
The generic engine is open source under MIT:
This is an independent, vendor-neutral visualization tool. Compatibility depends on the structure and meaning of the exported counters.
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