Correctly identifying a base station (gNB) is critical for site surveying and network verification. In the 3GPP 5G NR specification, the NR Cell Identity (NCI) is a 36-bit value — but how it’s split between the gNB ID (tower) and Cell ID (sector) varies between operators.
The NR Cell ID Format Tool handles this automatically for 50+ carriers worldwide, or lets you set a custom bit-split for private networks.
The Problem
Without the correct bit-split, your NCI will yield a “gNB ID” that doesn’t exist in any cell database. For example:
- O2 UK uses 22 bits for gNB ID / 14 bits for Cell ID
- Vodafone UK uses 24 bits for gNB ID / 12 bits for Cell ID
- EE UK uses 24 bits for gNB ID / 12 bits for Cell ID
If you apply the wrong split, you’ll get a completely different tower number — making it impossible to cross-reference with planning databases or drive test tools.
Auto-Detection Engine
CellInfo automatically detects your carrier’s MCC/MNC and applies the correct bit-split. Over 50 carriers are pre-configured across:
- 🇬🇧 United Kingdom (O2, Vodafone, EE, Three)
- 🇺🇸 United States (T-Mobile, AT&T, Verizon)
- 🇩🇪 Germany (Telekom, Vodafone, O2)
- 🇫🇷 France (Orange, SFR, Bouygues, Free)
- 🇦🇺 Australia (Telstra, Optus, TPG)
- 🇮🇳 India (Jio, Airtel, Vi)
- 🇯🇵 Japan (NTT Docomo, au, SoftBank)
- And many more…
No configuration needed — just connect to a 5G SA network and the correct format is applied automatically.
Manual Bit-Split Override
For private networks, newly deployed carriers, or testing environments where the auto-detection doesn’t have your operator:
- Open the 5G Lab tab
- Find the NR Cell ID Format card
- Tap Custom to switch from auto-detection to manual mode
- Adjust the slider to set your gNB bit length (20–32 bits)
The Cell ID bits are calculated automatically (36 minus your gNB bits).
When to use manual mode:
- Private 5G networks (MCC 001 or MCC 999)
- New carrier deployments not yet in the database
- When your gNB ID doesn’t match a known tower database
Live NCI Calculator
Paste or type any 36-bit NCI value to see its breakdown instantly:
- Input: Full NCI (e.g. 231735821)
- Output: gNB ID + Cell ID based on your current bit-split setting
Use this to validate data from outdoor surveys, colleague reports, or external tools.
Identifiers Explained
| Identifier | Bits | Purpose |
|---|---|---|
| NCI | 36 | Full NR Cell Identity (unique within PLMN) |
| gNB ID | 22–32 | Tower identifier (varies by operator) |
| Cell ID | 4–14 | Sector/antenna within the tower |
| PCI | 0–1007 | Physical signal identifier (radio-level) |
Why It Matters
Without the correct format, your NCI will yield a “gNB ID” that doesn’t exist in your cell database. This tool ensures 100% accuracy in base station mapping — essential for:
Identifying specific sectors for interference analysis
Drive testing and coverage verification
Site surveying and planning validation
Cross-referencing with operator tower databases