PCI conflict checker
Check a list of physical cell identities for direct collisions and mod-3 / mod-30 interference risk.
4 cells parsed.
- mod-3 overlap (PSS): Site A / Sector 1 (PCI 12) and Site A / Sector 2 (PCI 45)
- Direct collision: Site A / Sector 1 (PCI 12) and Site B / Sector 1 (PCI 12)
- mod-3 overlap (PSS): Site A / Sector 1 (PCI 12) and Site C / Sector 1 (PCI 75)
- mod-3 overlap (PSS): Site A / Sector 2 (PCI 45) and Site B / Sector 1 (PCI 12)
- mod-3 overlap (PSS): Site A / Sector 2 (PCI 45) and Site C / Sector 1 (PCI 75)
- mod-3 overlap (PSS): Site B / Sector 1 (PCI 12) and Site C / Sector 1 (PCI 75)
| Cell | PCI | Group | Sector |
|---|---|---|---|
| Site A / Sector 1 | 12 | 4 | 0 |
| Site A / Sector 2 | 45 | 15 | 0 |
| Site B / Sector 1 | 12 | 4 | 0 |
| Site C / Sector 1 | 75 | 25 | 0 |
The formula
PCI (0–503) splits into a group and a sector: PCI = 3 × group + sector (3GPP TS 36.211), group 0–167, sector 0–2.
- Same PCI on cells that can hear each other: a direct collision — phones can't tell them apart.
- Same PCI mod 3: shared primary sync sequence (PSS) — degrades cell search.
- Same PCI mod 30: shared secondary sync group (SSS) — smaller but real risk.