LPWA networks needs antennas and gateway to receive the device communication and transfer them to a network kernel. You can take a look to my post on the LPWA network architecture for more details.

In the LoRaWan ecosystem we call the first part of this network architecture a gateway. There are different kind of gateway : The network operator gateway with a big and efficient antenna, capable to support external weather like the Kerlink IoT Station and some low costs solution you can deploy at home or within a building (indoor) to cover a local device fleet.

The Kerlink Wirenet iFemtoCell device is a such type of gateway. this post will review how to get start with it and what we can expect in term of coverage.

Introduction

The Kerlink Wirenet iFemtoCell is a white peace of plastic looking really cheap but made to be unobtrusive. As usual the delivered documentation is light as nothing and once you plug it to power you see green lights but you are like a chicken with a knife. That’s for the first feeling you have once the box opened.

In term of hardware the solution is really nice : inexpensive price and the same performance as the IoT stations.

The documentation is accessible one the Kerlink wiki (http://wikikerlink.fr) where you need to have a login & password. So the first step once you open the box is to find a kerlink contact and request an access to the documentation, this will take a while and waste your time.

Getting start

The first time you need to connect it on you LAN to make the initial configuration. The device is configured to get an IP from a DHCP so you have to find the device IP from you router. The device name is like klk-wifc_XXXXXX where XXXXXX is the end of the device id as written on the back of the device.

Once done you can reach the administration page and jump back instantaneously about 20 years back on the first days of Internet. You may also note that this page requesting for your Wifi credential is not secured. back in the 1990th I said.

You may register the MAC address of the gateway in your DHCP to ensure the IP used by the station will be fixed.

Update the firmware

From your LAN or WLAN you can access the gateway using ssh. You can loggin as root with using as password pdmk-XXXXXX where XXXXXX is the end of the device id written on the back as BoardID.

My device version was 2.4.x and the first step was to upgrade the firmware to 3.1.3. The wiki explains how to do it and you should refer to it to avoid failure. Basically this step is simple : you transfer the .ipk file to the station in directory /user/.updates, flag a sw update using kerosd -u command and reboot to execute the upgrade.

You can check the version with the following command

cat /tmp/sys_startup_status.json | grep sw_version

The other way to manage upgrade is to use an USB storage to push the firmware. This way you can upgrade device deployed where you network access are restricted. Before going this way it is recommended to change the default password protecting the usb installation.

At this time you jump from the 90s to the 21th century ! wahooo !

Hard point to find in the wiki, the default login/pass is admin/admin…

Once logged you will not have a lot more setting than IP settings & WLAN settings. You can’t change the default password from the web interface, this point could be improved.

Add a packet forwarder

Kerlink station are not really ready for use. We could expect a such thing from a small device like the Wirenet iFemtoCell but in another hand we are also expecting to use the kernel network of our choice and packet forwarder is usually related to this. In my opinion a such device may have some of the main network kernel provider installed as default and configurable through the WebUi. May be for later versions with a market more mature.

To connect to TheThingsNetwork, the packet forwarder you can use is the Semtech packet forwarder (downloadable from kerlink wiki as an ipk). It is installed the same way as a new firmware.

Then you need to modify the /user/spf/etc/global_conf.json file

"gateway_conf": { 
 "gateway_ID": "7276FF00390300A0", 
 "server_address": "router.eu.thethings.network", 
 "serv_port_up": 1700, 
 "serv_port_down": 1700, 
 "keepalive_interval": 10, 
 "stat_interval": 30, 
 "push_timeout_ms": 100, 
 "forward_crc_valid": true, 
 "forward_crc_error": false, 
 "forward_crc_disabled": true 
}

The gateway ID to be set is located in the local_conf.json file. Once done, reboot the gateway.

Now you can create the gateway in the TTN console selecting a legacy packet forwarder. (note : the TTN will propose you different server & port but you need to use the one above)

At this point it work, the gateway is up & running on TheThingsNetwork.

If your firmware is 3.3.3 or earlier you must make some change in the /user/spf/bin/execute_spf.sh file. As the IpTables rules have been changed you need to replace the iptable -A option by a -I (i upercase). Otherwise your iFemToCell will never connect to TTN.

Add the cellular communication

The iFemToCell is compatible with Huaweu E3372 LTE usb Stick for cellular communication. The first step is to plug the Usb stick into the USB port and this is not the easiest part as the key is a little bit too large for the kerlink box.

To find the documentation, you need to connect to kerlink wiki, then go to the network management section and then click on the firmware you have (the version can be found in the web admin page of your gateway)

To configure cellular connectivity you need to connect to the station with SSH and make some changes:

In the file /etc/network/connman/main.conf

DefaultAutoConnectTechnologies = cellular, ethernet, wifi
PreferredTechnologies = cellular, ethernet, wifi

If you are using a firmware under 3.3.3

Run lsusb command,

If your device id is  Bus 001 Device 005: ID 12d1:14dc you need to follow the workaround describes in the kerlink wiki otherwise the modem is not detected.

Note that after a reboot the Dongle is not anymore usable … The procedure should be automated ? Apparently the last version of firmware 3.3.3 does not have to apply this workaround so I assume the best way is to upgrade if you have this version of LTE stick.

Now we can configure the LTE provider. By default for France you have Orange & SFR, to add bouygues you can add the following lines in the /etc/network/ofono/provisioning file

[operator:208,20] 
internet.AccessPointName=m2minternet 
[operator:208,21] 
internet.AccessPointName=m2minternet 
[operator:208,88] 
internet.AccessPointName=m2minternet

# you can also try
# BOUYGUES
[operator:208,20]
internet.AccessPointName=mmsbouygtel.com
internet.AuthenticationMethod=pap

Now we can stop & restart ophono after some cleaning

/etc/init.d/ofono stop
rm -rf /etc/network/ofono/**SIM_ID*
/etc/init.d/ofono start

Then activate gsm

# netctl --configure
# netctl --reconnect-cellular

These steps done you should be connected using cellular network.

You should see something like when typing ifconfig command

ppp0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 
 inet addr:10.212.32.165 P-t-P:10.212.32.165 Mask:255.255.255.255

You can now reboot the Kerlink to ensure you reconnect on bootup.

Note: with version 3.4.4 some new tools are provided. As an example you can verify the configuration with the gsmdiag.py script providing a txt based report.

Some other default settings are also provided in the ofono config: the AuthenticationMethod is chap and for some providers, pap is recommanded

internet.AuthenticationMethod=pap