Sigfox Ultra-Narrowband Transmission

Explore 3D-UNB time, frequency, and space diversity with a live spectrum workbench

animation

sigfox

lpwan

protocols

diversity

radio

An interactive Sigfox Ultra-Narrowband workbench showing 100 Hz channels, 3D diversity, payload limits, radio configuration tradeoffs, base-station reception, and cloud deduplication.

Sigfox 0G Ultra-narrowband LPWAN radio

Sigfox UNB sends tiny messages in narrow radio slices.

Use this workbench to see why Sigfox devices can stay simple: a small payload is sent as one or three narrow radio bursts, base stations listen across the band, and the cloud keeps one clean application message.

100 Hz Typical uplink burst width

3D Time, frequency, space diversity

12 bytes Maximum uplink payload

140/day Common duty-cycle design cap

3D-UNB Transmission Workbench

Adjust payload, radio configuration, copy count, noise, and interference. The spectrum, timeline, base station cards, and diagnosis update together.

Ready to transmit

Live spectrum and receiver view

RC1: 192 kHz uplink band around 868.130 MHz

Controls

Use presets for common radio situations, or tune each parameter. Step mode moves one stage at a time.

Scenario

Radio configuration

Transmission diversity

Uplink payload bytes

4 bytes

Narrowband interference

20%

Receiver link margin

16 dB

Clear field: all three copies are likely to reach at least one base station.

4 bytes Uplink payload

Fits inside the 12-byte Sigfox uplink limit.

1.45 s x 3 Frame airtime

Shorter payloads reduce radio-on time.

31.0 dB Noise bandwidth benefit

Compared with a 125 kHz reference receiver bandwidth.

3 copies Radio diversity

Frequency, time, and base-station space improve resilience.

Message delivered

At least one burst reaches at least one base station, so Sigfox Cloud can forward one deduplicated event.

What the learner should infer

UNB is not high throughput. Its strength is making small, infrequent reports robust with minimal device complexity.

What is moving?

The colored radio peaks are copies of the same device message. Their width is exaggerated so a 100 Hz burst is visible.

Why it matters

A narrow receiver bandwidth captures less noise. That helps tiny battery devices send small messages over long range.

Try first

Press Play, then switch to the interferer preset. Watch one copy fail while another frequency or base station still receives.

What to notice

The application does not receive three messages. Sigfox Cloud deduplicates radio copies and forwards one event.

1. Pack payload

Sensor data must fit into 0 to 12 uplink bytes. Binary packing matters.

2. Pick frequency

The device selects narrow carrier frequencies inside its regional allocation.

3. Send burst

A 100 Hz uplink concentrates energy in a narrow receiver bandwidth.

4. Add diversity

Optional extra bursts add time and frequency diversity at the cost of energy.

5. Hear in space

Several base stations can receive the same message with different RSSI/SNR.

6. Deduplicate

The cloud removes duplicate radio copies before the application callback.

Compact Quick Reference

Concept	Teaching value	Accuracy notes	Design consequence
Uplink payload	0 to 12 bytes excluding protocol headers.	Shorter messages can use shorter predefined frame times.	Pack binary fields; avoid ASCII strings unless the report is tiny.
Downlink payload	8 bytes, device-requested.	The network cannot push whenever it wants; the device must ask during an uplink flow.	Use downlink sparingly for compact configuration or commands.
3D-UNB	Diversity in time, frequency, and receiving base-station space.	Sigfox radio specs allow one or three uplink radio bursts.	Three copies improve resiliency but use more airtime and energy.
Duty-cycle region	RC1-style operation commonly maps to 36 s/hour at 1% duty cycle.	For 8 to 12 byte payloads, Sigfox documents about 6 messages/hour or 140/day.	Design for infrequent reports, alarms, or status changes.
Frequency hopping region	Some RCs require frequency hopping or listen-before-talk behavior.	Radio configuration, data rate, band, power, and access rules vary by region.	Never hard-code Europe-only radio assumptions into global device firmware.

Formula trace

Receiver noise scales with bandwidth. A useful teaching comparison is:

10 log10(125000 Hz / 100 Hz) = 31.0 dB

This is a bandwidth comparison, not a guarantee that every deployment gets 31 dB more link margin.

Reliability model

If copy success is independent with probability p, then:

P(any copy) = 1 - (1 - p)^n

Real networks also depend on fading, interference, antenna quality, deployment density, and local rules.

Common misconception

Triple transmission is not an acknowledgment. It is redundancy before the cloud. The application normally sees one deduplicated message, not three commands to process.

Deeper technical notes for advanced learners

Sigfox documentation names the radio protocol 3D-UNB: time diversity, frequency diversity, and space diversity. A device can transmit one burst for lower energy or three bursts for increased resiliency. Regional radio configurations set the center frequencies, uplink data rates, access mechanism, and power guidance. The workbench compresses time and exaggerates spectral width so the learning object is visible; the labels preserve the real units.

For payload size, the platform constrains application data to 12 uplink bytes and 8 downlink bytes. Downlink is device-managed: the device requests the downlink during an uplink exchange, then the network later sends the response if available. That is why this page treats Sigfox as excellent for small reports and poor for large transfers, real-time control, or firmware delivery over the UNB link alone.

Guided Practice

1. See the default

Press Play in Clear field.
Confirm that three bursts appear at different frequency offsets.
Notice that the cloud delivers one deduplicated event.

2. Stress frequency diversity

Select Narrow interferer.
Step through the bursts.
Find which copy lands closest to the interferer and whether another copy survives.

3. Compare energy choices

Select One burst, then switch back to Three radio bursts.
Compare the frame airtime and delivery diagnosis.
Explain when you would accept less resilience to save energy.