The Sigfox Micro basestation has been announced during the last Sigfox Connect event in Berlin. The base-station allow to extend the Sigfox public network, at low price, for your private location.

This post is detailing my experience with the micro base-station and the field test I’ve made on an industrial site.

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Sigfox Micro-Basestation characteristics

The Sigfox Micro-Basestation is an indoor / outdoor basestation made to extend the Sigfox public network. You can’t use it to create a private network actually. Even with the added cellular connectivity you can install it outdoor with the casing shown on the right.

The antenna is integrated and you have no option to add an external antenna. This option would have been really good but I assume Sigfox wants you to go to the mini-basestation if you need a larger coverage and a fix roof installation.

Sigfox is an asymetric network where the receiver hardware complexity is really higher than the emitter hardware complexity. The micro-basestation is a highly performant hardware with Sigfox dedicated FPGA for radio reception. This hardware is different from the Sigfox mini and standard basestations used by the operator in the public network. The main difference is related to the capacity of the micro base-station to proceed messages received in parallel. The micro-basestation is able to receive up-to 3 messages in parallel but not more. This includes the local messages you send as the distant messages sent by third party on the public network. Basically this can be a limitation for a dense area but in another hand, you should not need a micro gateway in a dense area where the public network is deployed.

The micro-basestation is a really good solution to cover at low cost deep indoor building or parking when the coverage is limited. It’s also a nice solution to cover industrial sites world-wide when the public network has not yet been deployed in your location. The public price may be about some hundreds of euro all included. The distribution network is still not totally clear. It seems they will be distributed by the Sigfox Network Operators (SNO). This is a negative point as the best way to make an easy access to the technology is to allow a direct distribution form the main resellers like mouser, digikey, element14, amazon …

Configure the Micro Base Station

The installation is really easy, the Sigfox micro-base-station is powered over Ethernet (PoE). It comes with a PoE injector and an associated power supply. The PoE injector is really looking like a PoE splitter so basically you will plug it incorrectly !! We have been a lot connecting it in reverse direction. So take a look to the documentation to ensure connecting it correctly. If you did not did it, you won’t see any led on.

Once correctly powered, you will see a led switching ON (red/orange/green) on the corner of the micro basestation. The stable Green LED is indicating the base-station as connected and ready.

The Sigfox Micro Base Station will be able to be configured with a web interface. Actually if you connect to the Sigfox micro base-station IP you will get a status page. This will help you to monitor the basestation status remotely. I would have expected an API endpoint for getting better monitoring. I expect Sigfox will provide a backend solution to monitor and alarm the micro base-stations.

The Web application will later allow to configure the Sigfox micro-basestation. This should be available on Q1 2019. Actually you setup it with an Android application (Sigfox Access Station Utility). This application is not compatible with all the android smartphone so you could not find it in the Play Store.

The application communicates with the Sigfox basestation using the USB connectivity. The Sigfox Basestation acts as an USB master for the phone.

Configure the LTE/4G Link

The Sigfox Micro Base Station is able to communicate over 3G/4G networks instead of Ethernet. This allows to install it everywhere in an easy way. The Sigfox Base-Station actually supports only two 3G & 4G dongles (HUAWEI MS2131i or MS2372h). They seems to be a bit outdated but easy to find on aliexpress for about 45€.

You may inactivate the Sim card PIN. I did not saw any place to set it up in the Sigfox tool. You can put the SIM card into a cellphone and inactivate the code in the security settings

Then you can setup the mobile connectivity ( APN, login, password…) with the Sigfox Access Station Utility. Go to Network tab, select Cellular and set the requested parameters. Then enter the information and click on Update Configuration button.

Once done, remove the cellphone USB cable. Plug the 4G dongle in the USB connector and reboot the Sigfox Micro Base-station.

Communications

The Sigfox micro base-station uses a VPN connect to Sigfox backend. This way the data are secured regarding the network operators transporting the base-station data. When a base-station is installed on a private network the messages can’t be accessed by the owner of this private network.

You can estimate the Sigfox communication volume to 10M-12M Bytes per day for a low device traffic. I’ve seen 6MB upload and 4MB download per day. This is a minimal 300MB-400MB monthly consumption if you need to size your cellular subscription.

This is twice the traffic I have with my LoRaWan gateway. In another hand the LoRaWan gateway I use with TTN do not use VPN and transport clear text json (with LoRaWan encrypted payload) over UDP.

For the test I’ve been using Soracom cellphone M2M data offering. This company proposes IoT communications with wold-wide Cellphone data SIMs and Sigfox subscriptions. Billing is based on real data consumption.

Field test

To test the Sigfox micro base-station, I’ve try to deploy it is a real industrial situation. I did not optimize its installation. I’ve deployed the base-station near my work desk in the industrial site where I’m working. The chosen place was really bad for many reasons:

• It was inside a building with really large wall
• It was on the 2nd floor of a 4 stairs building
• There was another big building in front of it
• The basestation was near a window (so far away the other side of the building)
• It was partially hide by the metallic window contour
• It has different computer and possible noise source really close.

According to this situation I was not especially expecting extraordinary results.

This is why the results surprised me. Basically the micro-basestation is covering the entire site. I’ve made my tests outdoor due to building access restriction. The following map shows (with white +) the locations around where RSSI is large enough to allow a indoor-indoor communications.

As a comparison I’ve made in parallel the same test with a LoRaWan Kerlink iFemToCell Gateway installed in the exact same conditions. The following map show the results with a SF7 Spread Factor (and a larger number of repeats and communication on the industrial site).

Even if we see a big difference, you need to keep in mind how the tests conditions were difficult. The installation of the base-stations did not allow a correct radio performance. In a normal installation situation a LoRaWAN gateway is covering a whole site of a such size. As an example of this, with an external antenna installed on my roof top I’m covering most of the industrial sites of the company I’m working for in this city.