Low frequencies (700–900 MHz) travel far and penetrate buildings → coverage. Mid bands (1.8–3.5 GHz) balance reach and capacity. mmWave (24–29 GHz) has huge bandwidth but tiny range → indoor capacity. Ordered low → high:
FDD uses paired spectrum — separate UL and DL frequencies running simultaneously. TDD uses a single frequency split in time between UL and DL, which is why TDD bands (n78, B40/n40) need tight phase sync and slot-format discipline that FDD bands (n28, B3, B8) don't.
| Band | Frequency | Duplex | FR | Role | Samsung radio |
|---|---|---|---|---|---|
n28 | 703–748 / 758–803 MHz | FDD | FR1 | 700 · 5G coverage | band in scope |
B8 / n8 | 880–915 / 925–960 MHz | FDD | FR1 | 900 · coverage, GSM refarm | RF2236-08A · RF6602-08A |
B3 | 1710–1785 / 1805–1880 MHz | FDD | FR1 | 1800 · coverage + capacity, DSS | RF4455 · RF4460 · RF4480 |
B40 / n40 | 2300–2400 MHz | TDD | FR1 | 2300 · TDD capacity | RT4436-40A · RT4448-40A |
B7 | 2500–2570 / 2620–2690 MHz | FDD | FR1 | 2600 · capacity | band in scope |
n41 | 2496–2690 MHz | TDD | FR1 | 2500 · 5G capacity | band in scope |
n77 | 3300–4200 MHz | TDD | FR1 | C-band (extended) | (n78 units cover the sub-range) |
n78 | 3300–3800 MHz | TDD | FR1 | 3.5 · primary 5G capacity | RT8813-78A · MT3212 · MT3234 |
n257 | 26.5–29.5 GHz | TDD | FR2 | mmWave indoor | LTM |
n258 | 24.25–27.5 GHz | TDD | FR2 | mmWave indoor | LTM |
n261 | 27.5–28.35 GHz | TDD | FR2 | mmWave indoor (US) | LTM |
A band is a range; a cell is a specific carrier inside it. In 5G NR that carrier is addressed by an NR-ARFCN (the global frequency raster), and the SSB the UE searches for sits on the GSCN sync raster — so the UE finds the cell without scanning every kilohertz.
| Concept | What it is |
|---|---|
| NR-ARFCN | Global frequency-channel number for the carrier centre on the NR global raster (0–3279165) |
| Channel raster | ΔFRaster step allowed for the carrier within the band (band-specific) |
| GSCN | Global Synchronization Channel Number — the sparse raster where SSB can be placed so the UE finds it fast |
| SSB / SCS | Sub-carrier spacing (FR1 15/30 kHz · FR2 120 kHz) sets slot length and the SSB pattern |
| Range (MHz) | ΔFGlobal | FREF-Offs | NREF-Offs | NR-ARFCN span | F = FREF-Offs + ΔF·(N − NREF-Offs) |
|---|---|---|---|---|---|
| 0 – 3000 | 5 kHz | 0 MHz | 0 | 0 – 599999 | e.g. n28: N=155050 → 775.25 MHz |
| 3000 – 24250 | 15 kHz | 3000 MHz | 600000 | 600000 – 2016666 | e.g. n78: N=636666 → 3549.99 MHz |
| 24250 – 100000 | 60 kHz | 24250.08 MHz | 2016667 | 2016667 – 3279165 | FR2 (n257/n258/n260/n261) |
current-tx-nr-arfcn / current-rx-nr-arfcn per carrier in …/radio-unit-info/carrier-control-info (AU PD SVR25B — see the AU MO tree on the Radios page). Audit rule: RU-reported ARFCN × this formula must land inside the band's licensed block — a mismatch means a mis-declared carrier, and it presents as "mystery interference".Band + duplex set the rules of the cell.
Coverage bands vs capacity bands, FDD vs TDD, FR1 vs FR2 — each dictates a different optimization posture. That completes 1.1 Hardware; from Day 2 the golden-parameter tuning begins.