LoRaWAN ADR Analysis
LoRaWAN ADR Analysis
SimulationLoRaWANAdaptive data rate
LoRaWAN ADR Analysis
Explore Adaptive Data Rate behavior and see how measured SNR becomes a discrete spreading-factor and transmit-power recommendation.
Available ADR margin
Quantised adjustments
Recommended spreading factor
Recommended TX power
TryEnter -10 dB for Measured SNR and select Calculate ADR step. Repeat with a stronger SNR while keeping the required SNR and installation margin unchanged.
ObserveStarting at -10 dB, ADR margin increases with measured SNR and crosses discrete thresholds; the recommendation lowers spreading factor or transmit power in steps.
ExplainAvailable margin equals the -10 dB measurement minus required SNR and safety margin. Dividing that surplus by the configured step size quantises the adjustment.
Technical boundariesThis single-link calculation omits gateway diversity, fading and interference distributions, regional channel plans, duty-cycle scheduling, retries, mobility, and vendor-specific network-server logic.
Colour keyLoRaWAN identitycurrent selectionSNR referencesafe adjustmenthold marginlink deficit
ADR Analysis Results
5.0 dBADR margin after installation reserve
1 stepWhole policy steps available
SF11Recommended spreading factor
14 dBmRecommended transmit power
0.50×Airtime versus current SF
2.0×Approximate packet capacity gain
SNR Requirements by Spreading Factor
ADR Decision Logic
- Measure. Use a stable uplink SNR history and identify the evidence value.
- Reserve. Subtract the SF requirement and installation margin.
- Lower SF first. Spend positive steps on faster data rates until SF7.
- Then lower power. Spend remaining steps without crossing the configured minimum.
One safe data-rate step is available.The model recommends SF11 while retaining 14 dBm.
ADR evidence and policy reference
Margin is evidence after reserve
Measured SNR alone is not the adjustment budget. The server compares that evidence with the demodulation requirement for the current spreading factor, then subtracts the installation margin reserved for fading, obstruction change, and measurement uncertainty.
A positive remainder means the link has surplus in this simplified model. A negative remainder means ADR must preserve or increase robustness; it must not spend margin that the evidence does not contain.
ADR margin = measured SNR − required SNR − installation margin
Quantisation prevents tiny reactions
The configured step size converts continuous SNR margin into whole policy actions. With a 3 dB step, 2.9 dB of surplus produces no adjustment, while 3.0 dB produces one. This threshold behaviour is why the recommendation can remain unchanged as the SNR slider moves.
The teaching sequence spends available actions on spreading factor first, down to SF7, then on transmit power without crossing the selected minimum. Real network servers can use different regional and vendor policies.
Nsteps = floor(ADR margin / policy step size), when margin ≥ 0
History matters more than one lucky uplink
A production server normally evaluates a history of uplinks received by one or more gateways. A single unusually strong packet can result from a temporary channel or placement state. A stable maximum, average, percentile, or vendor-specific statistic is safer evidence for a persistent radio change.
The SNR history samples control records that policy context but this calculator deliberately uses the entered measured value directly. That keeps the arithmetic inspectable while the Technical boundaries card names the omitted gateway-diversity and fading distributions.
Check airtime, capacity, and battery together
Lowering spreading factor shortens symbol duration. For this comparison, every one-step reduction halves the approximate airtime ratio, so the device transmits for less time and the shared channel can carry more packets. Those are directional planning indicators rather than a packet-level regional compliance result.
Transmit-power reduction can save additional energy once data rate reaches SF7. The correct endpoint is not minimum power at any cost: it is the lowest airtime and power combination that retains the chosen installation reserve in measured field conditions.
| Margin below 0 dB |
Hold SF and TX power |
No surplus is available to spend |
SNR distribution, loss rate, gateway count, obstruction state |
| Positive margin below one step |
Hold current settings |
The policy threshold has not been crossed |
More uplinks before treating the change as persistent |
| One or more steps, SF above 7 |
Lower spreading factor first |
Shorter airtime improves channel use and packet energy |
Post-change delivery and reserved fade margin |
| Steps remain at SF7 |
Lower TX power to the configured floor |
Data rate cannot rise further in this model |
Receiver margin and packet loss after every power change |
| Mobile or rapidly changing link |
Use ADR cautiously |
Historic evidence may not predict the next location |
Mobility state and device-side fallback behaviour |
Worked check
Subtract the required SNR and configured safety margin from the measured maximum SNR. Divide the remaining margin by the ADR step size to find the permitted data-rate or TX-power adjustment.