Calculator for Link Budget IoT - NB-IoT, LoRaWAN and 5G
Calculate RF link budget for NB-IoT, LoRaWAN (EU 868 MHz / US 915 MHz) and 5G NR with pre-configured technical presets. Estimate device IoT battery life. Friis FSPL formula verified (VERIFIED). Client-only, no data sent to server (D-53-07).
The link budget IoT determines whether a wireless device can communicate with the base station or gateway at a certain distance. The loss of path in free space (FSPL, Free-Space Path Loss) is calculated using Friis' formula: FSPL (dB) = 20 log10(d_km) + 20 log10(f_MHz) + 32.45. The link budget margin and the difference between the received power and the minimum sensitivity of the receiver.
NB-IoT (3GPP Release 13+) opera su bande LTE degli operatori (tipicamente 900 MHz in EU) con un MCL (Maximum Coupling Loss) di 164 dB [ASSUMED] - ideale per dispositivi in ambienti difficili. LoRaWAN (LoRa Alliance TS001) usa bande ISM non licenziate (868 MHz EU, 915 MHz US) con sensibilita fino a -137 dBm in SF12 BW125 [ASSUMED], raggiungendo 15-30 km in ambiente rurale. 5G NR offre throughput molto maggiore ma range limitato (tipicamente 0.1-2 km in ambiente urbano per la banda n78 a 3.5 GHz) [ASSUMED].
Values preset for sensitivity, TX power and antenna gain are assumed based on 3GPP and LoRa Alliance specifications. Must be verified against official radio module datasheets before deployment. FSPL calculation is verified; margin thresholds (10 dB = acceptable) are empirical engineering rules [ASSUMED].
Source RF: Friis transmission equation [VERIFIED]; 3GPP TS 36.101/38.101/TR 45.820 (preset NB-IoT/5G - [ASSUMED]); LoRa Alliance TS001 (preset LoRaWAN - [ASSUMED]). Normative version: IOT-RF-PRESETS-2026 (valid until 2026-07-21).
Section A - RF Link Budget Calculation
Preset values [ASSUMED] - verify against official module datasheet before deployment.
Parameter RF
Result Link Budget
Enter RF parameters and press "Calculate Link Budget" to get FSPL and margin.
Section B - Battery Life Estimation for IoT Devices
Battery Parameters
Life Worth Fighting For
Insert capacity (mAh) and average current (mA) to estimate battery life.
Frequently Asked Questions
What is FSPL and how is it calculated?
Free-Space Path Loss and radio signal power loss in free space, without obstacles. Calculated using Friis formula: FSPL (dB) = 20 log10(d_km) + 20 log10(f_MHz) + 32.45. For LoRaWAN at 915 MHz over 15 km: FSPL = 23.52 + 59.23 + 32.45 = 115.2 dB. At higher frequencies (5G 3.5 GHz), FSPL is significantly greater for the same distance.
What is the difference between NB-IoT and LoRaWAN?
NB-IoT is a 3GPP standard that operates on mobile operator LTE bands (800-900 MHz typical in EU). Requires SIM and subscription but offers widespread coverage from operators. LoRaWAN is a proprietary protocol (LoRa Alliance) operating on unlicensed ISM bands (868 MHz EU, 915 MHz US). Offers high range (15-30 km in rural areas) and low consumption, with gateway infrastructure managed by the deployer. 5G NR is the fifth generation cellular technology with shorter range but much higher throughput.
What does a 10 dB margin mean?
Link budget margin represents the "cushion" of power available beyond the minimum required for connection. A 10 dB margin is considered adequate for production systems as an empirical rule [ASSUMED - the precise value depends on the system availability requirements]. Margins 0-9 dB indicate a marginal link subject to interruptions in adverse conditions. Negative margins mean the connection is not practicable at the specified distance.
How do I calculate average battery life?
Average consumption depends on the IoT device duty cycle. For NB-IoT in PSM or eDRX mode, average consumption can drop to a few microamperes. For LoRaWAN with hourly transmission (SF12), typical current is 1-5 mA. Check radio module datasheets for actual values during transmit, receive, and sleep modes. The tool uses an 0.8 derating factor [ASSUMED] for effective battery capacity.
The results are accurate for real installations?
The FSPL formula by Friis is exact for free space [VERIFIED] but does not account for obstacle attenuation (trees, buildings), multipath, fading, and atmospheric conditions. The preset sensitivity and power values are [ASSUMED] and must be verified against the official module datasheets. For real installations, add a fade margin (typically 10-20 dB) to the estimated losses and conduct field measurements.
How is it used?
- Select IoT TechnologyUse pre-defined technological presets (NB-IoT, LoRaWAN EU, LoRaWAN US, 5G NR) to pre-compile typical parameters, or manually enter frequency, transmit power, antenna gain, and receiver sensitivity. All preset values are [ASSUMED] and must be verified against official 3GPP or LoRa Alliance specifications.
- Insert distance and RF parametersInsert distance in km between device and gateway/base station. Free Space Path Loss (FSPL) is calculated using Friis formula: FSPL (dB) = 20 log10(d_km) + 20 log10(f_MHz) + 32.45. Calculation occurs in browser - no data sent to server.
- Interpret the margin of connectionBorder RF shows if link is closed (>= 0 dB) and by what margin. Margin >= 10 dB considered adequate for production systems [ASSUMED - empirical engineering rule]; 0-9 dB marginal; < 0 dB means the connection is not practicable at that distance.
- Calculate Battery LifeInsert battery capacity (mAh) and average power consumption (mA) of the IoT device. The tool calculates estimated lifespan in hours and days, applying a 0.8 factor (80% usable capacity - empirical rule).
Practical example: Rural LoRaWAN 15km
Scenario: Soil moisture sensor LoRaWAN-US at 15 km from the gateway. Preset parameters for LoRaWAN-US.
- Distance: 15 km | Frequency: 915 MHz | Transmit Power: +14 dBm
- FSPL = 20 log10(15) + 20 log10(915) + 32.45 = 23.52 + 59.23 + 32.45 = 115.20 dB (Verified)
- Margin = 14 + 2 (TX antenna) + 5 (RX antenna) - 115.20 - (-137) = 42.80 dB
- Result: margin 42.8 dB - SUFFICIENT. Confirm that LoRaWAN is ideal for long-range rural applications.
Note: This is a gold test case for the tool (tolerance 0.05 dB). Preset parameters [ASSUMED] - verify with datasheet Semtech SX1276 or specify LoRa Alliance TS001 before deployment.
IoT Glossary for RF
- Free Space Path Loss
- Loss of signal power in free space (without obstacles). Calculated using the Friis formula: FSPL (dB) = 20 log10(d_km) + 20 log10(f_MHz) + 32.45.
- Margin Link Budget
- Margin between received power and minimum receiver sensitivity. Positive margin = closed link; > 10 dB = suitable for production [assumed empirical rule]; < 0 dB = impractical link.
- NB-IoT
- Narrowband IoT (3GPP Release 13+). LPWAN technology operating on LTE operator bands. Ideal for devices in harsh environments (bases, counters). Requires SIM and operator subscription.
- Low Power Wide Area Network
- Long Range WAN (LoRa Alliance). LPWAN protocol on unlicensed ISM bands: 868 MHz (EU), 915 MHz (US). Sensitivity SF12 up to -137 dBm [ASSUMED Semtech SX1276]. Range 15-30 km in rural areas, ultra-low power consumption.
- Receiver sensitivity
- Minimum power level (in dBm, negative value) that the receiver can correctly decode. Depends on Spreading Factor (LoRaWAN SF7-SF12), bandwidth, and chip technology. Lower values = better sensitivity.
Do you need a professional RF analysis?
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