Radio Configurations

Sigfox has a global coverage network, operating in unlicensed bands worldwide, with radio frequencies ranging from 862 to 928 MHz. Using unlicensed bands enable devices to send their data to the cloud while using little power, at very low cost. 

However, due to local regulations, laws or other operating constraints, the network configuration can differ from one country to the other.

Global operations are currently split into six geographical zones: from RC1 to RC6. More can come as the network adds new countries.

Each zone has a different set of parameters which clearly dimension the device hardware implementation: mainly frequency range, maximum radiated power, and radio front end specificities. 

Geographical zones

The current 6 zones with Sigfox radio configurations are:
  • RC1:
    • Europe: Belgium, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland, United Kingdom.
    • Overseas France: French Guiana, French Polynesia, Guadeloupe, Martinique, Mauritius, Mayotte, New Caledonia, Reunion.
    • Middle East and Africa: Iran, Kenya, Oman, South Africa, Tunisia, United Arab Emirates.
  • RC2: Brazil, Canada, Mexico, Puerto Rico, USA.
  • RC3: Japan.
  • RC4:
    • Latin America: Argentina, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Panama, Peru, Uruguay.
    • Asia Pacific: Australia, Hong Kong, Malaysia, New Zealand, Singapore, Taiwan, Thailand.
  • RC5: South Korea.
  • RC6: India.

See the Sigfox Coverage page to view radio presence in the whole world, and the name of all local Sigfox Operators.

RC technical details

Sigfox Radio Configuration (RC) defines the radio parameters in which the device shall operate: Sigfox operating frequencies, output power, spectrum access mechanism, throughput, coexistence with other radio technologies, etc.

Each radio configuration includes 4 uplink classes: 0u, 1u, 2u, and 3u.

The Sigfox network globally works within the ranges from 862 to 928 MHz. But not all RCs require such a wide range of operation.

  RC1 RC2 RC3 RC4 RC5 RC6
Uplink center frequency (MHz) 868.130 902.200 923.200 920.800 923.300 865.200
Downlink center frequency (MHz) 869.525 905.200 922.200 922.300 922.300 866,300
Uplink data rate (bit/s) 100 600 100 600 100 100
Downlink data rate (bit/s) 600 600 600 600 600 600
Sigfox recommended EIRP (dBm) 16 24 16 24 14 16
Specifics Duty cycle 1% * Frequency hopping ** Listen Before Talk *** Frequency hopping ** Listen Before Talk ***  
  • * Duty cycle is 1% of the time per hour (36 seconds). For an 8 to 12 bytes payload, this means 6 messages per hour, 140 per day.
  • ** Frequency hopping: The device broadcasts each message 3 times on 3 different frequencies. Maximum On time 400 ms per channel. No new emission before 20 s.
  • *** Listen Before Talk: Devices must verify that the Sigfox-operated 200 kHz channel is free of any signal stronger than −80 dBm before transmitting. 

Sigfox’s high limit EIRP recommendation is included in each column although regulations sometimes allow for more radiated power than the Sigfox recommendation.

Sigfox’s recommendation is set to comply with the Sigfox technological approach of:

  • Low current consumption
  • Balanced link budget between uplink and downlink communication

About Sigfox Classes

What are Sigfox classes?

Sigfox defines an uplink classification for each RC, which applies to every device and is assessed when passing the Sigfox Ready certification.

These classes are ranked from strongest to weakest: U0, U1, U2, and U3. They indicate the RF radiated performance of a device, which can have a significant impact on the message success rate. They are based on EIRP (effective isotropic radiated power) intervals.

Simply put, a U0 device enjoys a much better message reception than a non-U0 device. This means better user feedback and fewer support requests for your team.

For instance, in RC1, U0 must have a low EIRP limit of 12 dBm. In RC2, the low limit is at 20 dBm. See more in this document.

Therefore, while not mandatory, U0 is the class to aim for when building a device in the majority of use-cases. It is the best way to ensure Sigfox Network Service delivery at nominal performance level. In essence, the network is deployed to connect U0 devices.

Tips to improve emission power

Anything that is added between the module and the open air can lower the EIRP of your device: the antenna itself can lower EIRP by 2 dBm, the casing also has a strong impact, the way the insides of the device is organized can have an impact, same for the ground plane, etc.

There are best practices to follow when building a device, that will ensure maximal emission power:

  • Plan for U0 at the very start of your project. That means integrating the complete RF design (including antenna and mechanical designs) early on, to maximize your chances to be U0 without having to deeply rework your plan later on.
  • Start with a powerful radio base. For instance, choose a very good module/transceiver, so that weakening elements cannot bring the device's EIRP lower than 12 dBm. This means choosing a module/transceiver according to your target RCs. For instance, in RC1, use a module/transceiver that can broadcast at least at 19 to 20 dBm.
  • Choose your antenna carefully. Better yet: hire an antenna specialist. You can find some on Sigfox Partner Network.
  • Never use a metal casing for the radio part! Prefer a plastic casing. Note that you can choose to have part of your device in a metal casing, provided that the device will be placed on a metal support (antenna, etc.).
  • Leave room within the device, to favor a bigger antenna. This might mean a slightly bigger casing.
  • Test the complete device, not with just a PCB and an antenna: include the casing and any other component that might have an impact on emission.

The two best tips:

  • Aim for U0.
  • Hire an antenna designer early on.

When is U1 enough?

You should always aim for the U0 class. Because the Sigfox coverage is calculated for U0 devices, non-U0 devices might not get the coverage they need. Try simulating coverage for U1 to U3 in the Sigfox backend and see whether it suits your project's needs.

That being said, U0 is not mandatory, U1 or even U2 might be enough when some conditions are available:

  • The device is located in a fixed location, with a dense network.
  • The device is located outside, on a high tower.

In any other case, U0 should be the target. The Sigfox Device Cookbook has a whole section dedicated to matching use-case and device class.

Keep in mind that it is very hard to update a U1 device to a U0 one. If you chose to commercialize a U1 device and you get bad customer feedback about the reception, you will have to rework your device from the start in order to reach U0. It is much easier to aim for U0 right from the start.

Energy consideration

With a good antenna design, you can lower the device's radiated power on purpose from U0 to U1 or even U2, thus saving energy.
However, this implies to have perfect network conditions and a close monitoring of the message success rate. This can mean improving the local network by adding Micro Base Stations, which are specificically created for Smart Building and Smart Warehouse usecases.

For example, if you set the transceiver output power at 0dB instead of 14dB you can save about 50% power. This output power can be changed by downlink after installation to optimize the battery life when level of reception is good enough and position is fixed.

The transceiver output power can also be set at factory level for energy-saving purpose. You have to know what you are doing here (see the "When is U1 enough?" section)! In that case, class U1 or U2 doesn’t mean the hardware is not U0 capable.

How to achieve multi-RC?

Devices can be adapted to one or several Radio Configurations, which are primarily defined by the frequency range that is used, and the radiated power for the device.

Building a multi-RC device implies many aspects that must be taken into consideration:

  • Business case for having a multi-RC device,
  • Available space on the PCB,
  • Energy consumption,
  • Device performance,
  • Modularity and potential evolution,
  • Quantity of devices you expect to build/sell,
  • Manufacturing price, 
  • etc.

All of this also ties up with your technical team: which technology they are used to work with, what their radio skills are, etc.

Because of this, it is most of the time more interesting to build per-RC variations of your device, rather than invest in integrating more than one RC on a single device.

All in all, it all comes down to having a solid business case: whether you can justify the price and additional work or not, or if multi-RC is an explicit request from your client/market.

About Sigfox Monarch

Sigfox Monarch provides a unique radio recognition feature of the Sigfox network. It enables devices to manage the radio frequency changes, without any additional hardware such as GPS or Wi-Fi chipset.

This feature enables devices to run seamlessly in all parts of the world, by automatically recognizing and adapting to the local radio frequency standards. It unlocks endless use cases in logistics and supply chain, the consumer industry, and in the automated maintenance for the shipping, aircraft and railway industries. 

RC-specific technical information

Radio Configuration can have local peculiarities, which you should be aware of when developing your device.

This section lists the peculiarities which we are aware of.

RC3c: Managing noisy environment

Listen Before Talk (LBT) is a feature specified by the Japanese regulatory authority ARIB, that mandates devices to verify that the Sigfox operated 200 kHz channel is free of any signal stronger than −80 dBm before transmitting.

Recent field testing in RC3c/Japan revealed that Sigfox devices can be installed in very noisy RF environment that can potentially block message transmission due to the LBT mechanism, and consequently drastically decrease message transmission success rate.

The impact on the Quality of Service can be very serious. The application note below aims at educating device partners on such complex RF environment as well as providing guidance on different technical topics (Hardware, Software, Testing, etc.) to maximize the Message Success Rate.