5G NR PCI Planning Guide

PCI structure

PCI = 3 * N_ID^(1) + N_ID^(2)

Where:
  N_ID^(2) = PCI mod 3 (derived from PSS, 0 to 2)
  N_ID^(1) = PCI div 3 (derived from SSS, 0 to 335)

Total PCI range: 0 to 1007 (1008 values)

Planning rules

1. No PCI collision in first order neighbor set (exact PCI match)
2. No mod 3 conflict (PSS correlation reduces cell detection)
3. No mod 30 conflict (DMRS sequence correlation on data channels)
4. No PCI confusion in second order neighbor set
5. Reuse PCIs from geographically distant clusters
6. Avoid same SSB beam index for directly visible neighbors in FR2

Allocation example

New site S0 with 5 neighbor sites:
  S1: PCIs 12, 13, 14 (mod 3: 0, 1, 2 ; mod 30: 12, 13, 14)
  S2: PCIs 33, 34, 35 (mod 3: 0, 1, 2 ; mod 30: 3, 4, 5)
  S3: PCIs 66, 67, 68 (mod 3: 0, 1, 2 ; mod 30: 6, 7, 8)
  S4: PCIs 99, 100, 101 (mod 3: 0, 1, 2 ; mod 30: 9, 10, 11)
  S5: PCIs 132, 133, 134 (mod 3: 0, 1, 2 ; mod 30: 12, 13, 14)

Allocation for S0 (avoid all conflicts):
  Sector 1 (mod 3 = 0): PCI 18 (mod 30 = 18, no conflict)
  Sector 2 (mod 3 = 1): PCI 19 (mod 30 = 19, no conflict)
  Sector 3 (mod 3 = 2): PCI 20 (mod 30 = 20, no conflict)

PCI conflict detection on your device

HiCellTek RF Monitor highlights in real time any neighbor that shares PCI mod 3 or mod 30 with the serving cell. Essential for cluster audits and post optimization verification.