5G Link Budget Calculator

Q: Why is the real cell range smaller than free-space?

Free-space assumes line of sight (exponent 2). Real terrain adds clutter and diffraction, modelled with a higher exponent (3.5 urban, 4+ dense), shrinking the range.

Q: Does higher frequency reduce coverage?

Yes. Path loss rises with frequency, so 3.5 GHz 5G has about 10 dB more loss than 1.8 GHz LTE, giving smaller cells.

Tx power (dBm)

Tx antenna gain (dBi)

Cable / feeder loss (dB)

Rx antenna gain (dBi)

Rx sensitivity (dBm)

Frequency (MHz)

Fade margin (dB)

Other margins — body, interference, penetration (dB)

Path-loss exponent n (free space 2.0 · urban 3.5 · dense 4.0)

Defaults model a 3.5 GHz macro downlink (43 dBm, 16 dBi). Free-space range is a line-of-sight upper bound; the n-exponent range is more realistic for real terrain.

How it worksThe link-budget chain

A link budget adds up every gain and loss between transmitter and receiver to find how much path loss the link can tolerate — the MAPL — and hence the range:

EIRP = P_tx + G_tx − L_cable
MAPL = EIRP + G_rx − (fade + other margins) − Rx sensitivity

FSPL(dB) = 32.44 + 20·log₁₀(f_MHz) + 20·log₁₀(d_km)
range (urban) = 10^((MAPL − FSPL@1km) / (10·n))

The maximum allowable path loss is the headline number: any cell whose path loss stays below it is covered. Free-space loss (n = 2) is optimistic; real networks use a path-loss exponent of about 3.5 in urban and 4+ in dense urban areas, which is why the realistic range is far shorter than the line-of-sight figure. 5G mid-band (3.5 GHz) has ~10 dB more path loss than LTE at 1.8 GHz, shrinking the cell.

FAQFrequently asked questions

What is MAPL in a link budget?

MAPL (Maximum Allowable Path Loss) is the largest path loss the link can tolerate while still meeting the receiver's sensitivity. MAPL = EIRP + Rx gain − margins − Rx sensitivity. It directly sets the cell range.

What is EIRP?

EIRP (Effective Isotropic Radiated Power) is the transmit power after antenna gain and feeder loss: EIRP = P_tx + G_tx − L_cable. It is the power an ideal isotropic antenna would need to match your antenna's peak.

Why is the real cell range smaller than free-space?

Free-space loss assumes an unobstructed line of sight (path-loss exponent 2). Real environments add diffraction, clutter and reflections, modelled with a higher exponent (~3.5 urban, 4+ dense), so the realistic range is a fraction of the line-of-sight value.

Does higher frequency reduce coverage?

Yes. Free-space loss rises 20 dB per decade of frequency, so 3.5 GHz 5G has roughly 10 dB more path loss than 1.8 GHz LTE for the same distance, meaning smaller cells and more sites for the same area.

How it worksThe link-budget chain

FAQFrequently asked questions

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