LTE / 5G Link Budget and MAPL Calculator (DL and UL)
Find which link limits your coverage, uplink or downlink.
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LTE / 5G Link Budget and MAPL Calculator (DL and UL) by TheCalcTools
How the LTE / 5G Link Budget and MAPL Calculator (DL and UL) works
Downlink: the per-resource-element power (transmit power ÷ 12 × PRBs) plus antenna gain minus feeder loss, compared with the minimum RSRP at the cell edge.
Uplink: UE power minus the base station sensitivity (noise floor of the allocated PRBs + noise figure + required SINR), plus gains and TMA.
Margins for penetration, body, shadow fading and interference apply to both.
The formula
Worked example
Using the default values shown in the calculator:
| gNB/eNB transmit power (dBm) | 46 dBm |
|---|---|
| Carrier bandwidth | 20 MHz (100 PRB) |
| Base station antenna gain (dBi) | 17 |
| Feeder and connector loss (dB) | 1.5 |
| Minimum RSRP at cell edge (dBm) | -110 |
| UE transmit power (dBm) | 23 |
| UL PRBs allocated at the edge | 10 |
| Base station noise figure (dB) | 3 |
| Required uplink SINR (dB) | -3 |
| Tower-mounted amplifier gain (dB) | 0 |
| Penetration / building loss (dB) | 12 |
| Body loss (dB) | 3 |
| Shadow fading margin (dB) | 8 |
| Interference margin (dB) | 3 |
- DL MAPL = 46 − 10 log₁₀(1,200) − 1.5 + 17 + 110 − 12 − 3 − 8 − 3 = 114.7 dB.
- UL sensitivity = -111.4 dBm; UL MAPL = 123.9 dB. The Downlink limits coverage by -9.2 dB.
Result:
| Downlink MAPL (dB) | 114.7 |
|---|---|
| Uplink receiver sensitivity (dBm) | -111.4 |
| Uplink MAPL (dB) | 123.9 |
| Coverage-limiting MAPL (dB) | 114.7 |
| Limiting link | Downlink |
| Imbalance (DL − UL, dB) | -9.2 |
Frequently asked questions
Why is the uplink usually the limit?
A phone transmits only about 23 dBm versus 46 dBm or more from the base station, so the uplink budget runs out first unless the base station receive chain is very good.
How can I fix an uplink-limited cell?
Reduce feeder loss (RRH on the tower), add a TMA, use uplink carrier aggregation or a lower frequency anchor, or reduce margins by antenna height and tilt optimisation.
Sources and further reading
- 3GPP TS 36.211 / 36.213 / 36.101 (LTE)
- 3GPP TS 38.101-1: NR UE radio transmission and reception, Range 1
- Wikipedia: Link budget
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.