New episode of my LPWAn post series, this time, about the network architecture and the role of the network kernel.
The network architecture is different than a classical IP communication from client to server: the LPWAn architecture is based on a kernel network allowing the protocol transformation from the Sigfox / LoRaWan world to the IP-Internet world.
In the LPWAn protocol the addressing is limited to one device address only to reduce the frame size and as a consequence all the frame have to be captured by a central system: the network kernel. It will route the message correctly to the end user application based on device association made on registration.
This post is related to a french video (as usual) and detailed in the following part of this post.
The Things Network (TTN) is a global LoRaWan public network kernel based on crowd-source infrastructure. This initiative sounds really interesting in my point of view because it breaks one of the main LoRaWan issues : the country based operators organization.
Related to this good point, the negative point is the current area covered by a such network limited to the contributor localization, generally in the main cities.
That said, I’m convinced : when you want to create a private LoRaWan network you have to manage a network kernel managing gateways, device authorizations… You can do it yourself, you can pay someone to do it for you or, eventually, you can lever TTN for this use. As a counterpart you will extend the network and offer this benefit to any around. That way it makes sense and gives large opportunities to the networks and it’s private users.
Long introduction for a technical topic … How to join this network once you have a Kerlink LoRa Iot station available ? Continue reading →
Episode 3 & 4 of my Youtube series about LPWAN is about antennas for LPWAN and impact on object design. The episode 4 go deeper on the way to improve radio performance by tuning and adapting antennas with matching circuit.
As usual, this series of post are summarizing in English the content of my French video on youtube.
The RF 868MHz is a public bandwidth European Low Power Networks (LPWAN) as Sigfox and LoRaWan are using for communicating.
This bandwidth is regulated by different norms like ERC-REC-70-3E in Europe and have national norms in relation. In France ARCEP 2014-1263 seems to be the last one validated in the JO on the 30th of January 2015. The following video is a second episode of my VLOG on LPWan technologies. As usual, the video is in French but this post will give you a overview in english.
I’m actually doing some experiment with the French LoraWan network operated by Objenious. To receive the message on your backend application, one of the way is to build a callback function to proceed the data.
Due to LoraWan protocol, you have different type of possible callback like for: joining network, uplink messages and downlink report.
This post gives an exemple on how to implement an uplink message callback handler, with php, for your application backend server.
Today Sigfox is releasing a really good document about antenna design. This pretty document can be found following this link (available on July 7th). This document from TI also contains really well detailed information about the alchemy of antennas and the different kind of product you can find. From Silicon Labs you also have an interesting development kit for 868 antennas with performance published in this application note.
This is to say antenna is one of the most important part of a 868 object, as for Sigfox as for LoRa where the problem is basically the same. I discussed with different sigfox object designed and every-time the antenna was a big project issue. Some has payed about 10-15k€ to get a custom optimized design.
I never experiment a custom design but I made test with various antennas and the purpose of this post will be to give you my feedback on the different solutions.
After making LoRaWan test in a city environment, I make some test in a rural environment with the objective of evaluating the capability for being used in connected farming environment.
The result is really like what we have got in a city, eventually better in a way as the antenna position was on altitude. The following map makes with 6kbps communication shows the coverage. You can see that the coverage is really limited on the Eastern direction. This is due to higher mountains this way. Mountain are the main limiting elements and as you can see, even on short distance communication they are blocking any signal.
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