What are the two 5G frequency ranges FR1 and FR2, and what is the fundamental trade-off between them?
FR1 spans 450 MHz–6 GHz (sub-6) and FR2 spans 24–52 GHz (millimetre wave). Higher frequencies (FR2/mmWave) give much higher data rates but over much shorter distances — there is a negative relationship between frequency and range.
The two ranges:
| Range | Spectrum | Character |
|---|---|---|
| FR1 | 450 MHz – 6 GHz | "sub-6 GHz" — good range, moderate speed |
| FR2 | 24 GHz – 52 GHz | mmWave (millimetre wave) — huge speed, short range |
The core physics — frequency vs. range trade-off:
The higher the frequency, the shorter the range.
mmWave (radio frequencies roughly 30–300 GHz) promises incomparably better transmission speeds, but suffers high attenuation — the signal loses strength quickly when absorbed by air or moisture. This is why 5G distinguishes low (600–850 MHz), mid (2.5–3.7 GHz), and high (25–39 GHz) spectrum, each with different characteristics: higher bands give better speed at the cost of coverage.
The deployment consequence: mmWave needs pico-cells (cell diameter 10–100 m) and therefore a massive, dense roll-out of new base stations — you can't cover a country with mmWave the way you can with sub-6.
Tip: FR1 = "reach," FR2 = "speed." The whole small-cell story below is a direct consequence of choosing mmWave for the high-speed band.
Go deeper:
5G mmWave: Millimetre Wave (Electronics Notes) — why FR2 signals don't pass through walls, drop to ~200–300 m outdoors, and need beamforming — the propagation physics behind the FR1/FR2 split.- An Introduction to the 5G Frequency Spectrum (Knowles) — a clear FR1-vs-FR2 breakdown with the actual sub-6 GHz and mmWave band numbers and the speed-vs-coverage trade-off charted out.