Wireless Standards and Protocols IoT and LPWAN Informational

What is the link budget for a LoRaWAN device at maximum spreading factor?

What is the link budget for a LoRaWAN device at maximum spreading factor (SF12)? The LoRaWAN link budget at SF12 is one of the most generous in all wireless communication, enabling multi-kilometer range with milliwatt-level transmitters: (1) Link budget calculation: TX power: +14 dBm (typical for EU 868 MHz regulation) or +22 dBm (with SX1262 in US 915 MHz). TX antenna gain: +2 dBi (quarter-wave monopole). EIRP: +14 + 2 = +16 dBm (EU) or +22 + 2 = +24 dBm (US). RX sensitivity at SF12, 125 kHz BW: -137 dBm. RX antenna gain: +3 dBi (gateway antenna, vertical collinear). Total link budget: EIRP - sensitivity + RX antenna gain = 16 - (-137) + 3 = 156 dB (EU) or 24 - (-137) + 3 = 164 dB (US). (2) Available margin: free-space path loss at 868 MHz, 10 km: FSPL = 20 log(10000) + 20 log(868e6) + 20 log(4π/c) = 80 + 178.8 + (-147.6) = 111.2 dB. Margin at 10 km: 156 - 111 = 45 dB (EU) or 164 - 111 = 53 dB (US). This 45-53 dB margin accounts for: building penetration loss: 10-25 dB (depending on material). Foliage/obstruction loss: 5-15 dB. Fading margin (log-normal shadowing): 10-15 dB. Cable/connector losses at gateway: 1-3 dB. Even after all losses: 0-20 dB of margin remains at 10 km. In rural LOS: ranges of 15-30 km are frequently achieved. (3) What limits the range: in practice, LoRaWAN range is limited by: obstructions (buildings, terrain), not link budget. The link budget is so generous that the limiting factor is usually the path profile (hills, buildings) rather than the raw power. Gateway antenna height is the most impactful factor: raising the gateway antenna from 5 m to 30 m typically doubles or triples the coverage area. (4) Data rate at maximum range: at SF12 with 125 kHz: data rate = 250 bps. A 20-byte payload takes approximately 1.5 seconds of airtime. Duty cycle at 868 MHz (1%): one transmission every 150 seconds. This limits the application to infrequent reporting (1 message every 2.5 minutes maximum).

Category: Wireless Standards and Protocols

Updated: April 2026

Product Tie-In: IoT Modules, Filters, Antennas

LoRaWAN SF12 Link Budget

The LoRaWAN link budget at SF12 exceeds that of any other consumer/IoT technology, rivaling satellite communication in its ability to close the link over extreme distances.

Comparison to Other Technologies

(1) LoRa SF12: link budget ≈ 156-164 dB. BLE 5 Long Range (coded PHY, 125 kbps): TX +8 dBm, RX -103 dBm → 111 dB link budget. NB-IoT: TX +23 dBm, RX -141 dBm → 164 dB (comparable to LoRa US). Wi-Fi (802.11ax, MCS0, 20 MHz): TX +20 dBm, RX -95 dBm → 115 dB. (2) LoRa achieves its link budget through: ultra-narrow noise bandwidth (125 kHz → low noise floor), chirp spreading (20 dB processing gain at SF12), and sub-GHz frequency (lower path loss than 2.4/5 GHz). The cost: 250 bps data rate (4000× slower than BLE, 1,000,000× slower than Wi-Fi).

LoRaWAN Link Budget

TX: +14 dBm (EU) / +22 dBm (US)
RX @ SF12: -137 dBm, BW 125 kHz
Link budget: 156 dB (EU) / 164 dB (US)
FSPL at 868 MHz, 10 km: 111 dB
Margin at 10 km: 45-53 dB (excellent)

Common Questions

Frequently Asked Questions

What is the maximum real-world LoRa range?

World records: 832 km (balloon-to-ground, line of sight, 2017). Typical real-world: rural: 10-15 km (ground level). Suburban: 3-8 km. Urban: 1-3 km. Building-to-building: 500 m-2 km. The range is determined more by obstruction losses than by the link budget. Raising the gateway to 30-50 m height dramatically improves coverage.

How do I improve LoRaWAN coverage?

In order of impact: (1) Raise the gateway antenna height (from 5 m to 30 m: 2-3× coverage area improvement). (2) Use a higher-gain gateway antenna (collinear vertical, 6-8 dBi instead of 3 dBi). (3) Add more gateways (the cheapest way to fill coverage gaps). (4) Use SF12 on edge devices (maximum sensitivity). (5) Improve device antenna efficiency (avoid poorly matched or detuned antennas).

Why is the US link budget 8 dB better than EU?

The US FCC allows +30 dBm conducted power at 915 MHz (with FHSS), while EU ETSI limits to +14 dBm ERP at 868 MHz. This 8 dB difference in TX power translates directly to 8 dB more link budget. In the US: use the SX1262 PA at +22 dBm (or the full +30 dBm with external PA and FHSS compliance). In Europe: the lower power is partially compensated by lower path loss at 868 MHz (3 dB less than 915 MHz) and lower ambient noise.

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