Link Budget Calculator
5G NR and LTE link budget — compute EIRP, RX sensitivity, MAPL, and cell radius using TR 38.901 UMa or COST-231 Hata, whichever fits your frequency.
A link budget is the accounting sheet of an RF link. It sums every gain and loss between the transmitter and the receiver to determine the Maximum Allowable Path Loss (MAPL) — the largest distance-induced attenuation the link can survive while still meeting the target SINR. Once you know MAPL, a propagation model converts it into a cell radius. This calculator implements the textbook 3GPP-style link budget: EIRP minus RX sensitivity minus margins yields MAPL, which is then inverted through a propagation model to produce a cell radius in kilometres. The model follows your carrier frequency: COST-231 Hata is only specified for 1.5-2 GHz, so at 3.5 GHz and above the tool uses TR 38.901 UMa NLOS — the model 3GPP itself uses for NR — and says which one it applied. Tune the defaults to your specific scenario — frequency, bandwidth, required SINR, fade margin, penetration loss — and the numbers update instantly.
Transmitter (gNB / eNB)
Channel
Receiver (UE)
Margins & Losses
How It Works
The calculator performs the following steps:
- EIRP = TX power + TX antenna gain − feeder loss.
- Thermal noise = −174 dBm/Hz + 10·log₁₀(BW_Hz).
- RX sensitivity = thermal noise + noise figure + required SINR.
- MAPL = EIRP − RX sensitivity + RX antenna gain − (fade margin + interference margin + body loss + penetration loss).
- Cell radius is found by inverting the propagation model for d given L = MAPL and f: COST-231 Hata inside 1.5-2 GHz (which also uses h_b), TR 38.901 UMa NLOS outside it.
COST-231 Hata (urban) formula used: L = 46.3 + 33.9·log₁₀(f_MHz) − 13.82·log₁₀(h_b) − a(h_m) + (44.9 − 6.55·log₁₀(h_b))·log₁₀(d_km). It is valid for 1500–2000 MHz strictly, and commonly extrapolated to ~3.5 GHz for 5G mid-band planning.
3GPP References
- • TR 36.942 §4.5 — LTE link budget methodology
- • TR 38.901 — Study on channel model for frequencies from 0.5 to 100 GHz
- • COST-231 Hata urban propagation model (valid 1.5-2 GHz)
- • ITU-R P.1411 — Propagation data for short-range outdoor links
How to use the Link Budget Calculator
- Set the transmitter. Enter the gNB/eNB transmit power, antenna gain, feeder loss and base-station antenna height.
- Describe the channel. Enter the carrier frequency and channel bandwidth (for example 3500 MHz and 100 MHz for n78).
- Set the receiver. Enter the UE antenna gain, noise figure and the required SINR at cell edge.
- Add margins and losses. Enter shadow-fade, interference, body and penetration margins to match your coverage target and environment.
- Read EIRP, sensitivity, MAPL and radius. The tool shows EIRP, RX sensitivity and MAPL, then turns the MAPL into a cell radius via the COST-231 Hata urban model.
Frequently asked questions
- What is MAPL in a link budget?
- MAPL is the Maximum Allowable Path Loss — the largest propagation loss a link can tolerate and still close. In this tool it is EIRP minus the receiver sensitivity, plus the receive antenna gain, minus the combined margins and losses (fade, interference, body and penetration). Feed the MAPL into a propagation model and you get the cell radius.
- How do you calculate EIRP?
- EIRP (Effective Isotropic Radiated Power) is the transmit power plus the antenna gain minus the feeder and cable loss: EIRP = Tx power (dBm) + Tx antenna gain (dBi) − feeder loss (dB). It represents the power as if radiated equally in all directions from an ideal isotropic antenna.
- How is 5G receiver sensitivity calculated?
- Sensitivity is the weakest signal the receiver can still demodulate at the target quality. It is the thermal noise floor over the channel bandwidth (about −174 dBm/Hz plus 10·log10 of the bandwidth in Hz), plus the receiver noise figure, plus the required SINR. A wider channel raises the noise floor, so all else equal a 100 MHz carrier is less sensitive than a 20 MHz one.
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