Sigfox phase decoding
Sigfox is a LPWAn communication technology and network dedicated to IoT. The specificity of this solution is related to the LPWAn caracteristics : communicating Low Power (25mW) and Wide Area (60km).
This is possible thanks to particular radio characteristics and modulation. This post will describes how it works at radio level and protocol level.
Sigfox is a LPWA network using the free radio frequency to communicate. There radio frequencies are changing in the different zone (Europe, America, Asia…) When you are developing a device you need to test it but you are not authorized to use all these frequency from the country you are.
The Sigfox emulator is a solution for this : it allows to directly connect your device and analyze the transmission whatever the frequency you are using is. The Sigfox emulator kit is an SDR dongle with a Sigfox software for understanding, decoding the sigfox signals.
You can wire your transmitter to this receiver to not emit the signal over-the-air and legally use a non authorized frequency in your country. When you are using an authorized frequency you can simply communicate over the air.
Sigfox has just published a documentation on the technical basis of the network. This pdf document is a good summary of all what you need to know to get start on the technology.
The document is attached here Sigfox technical overview
To complete this overview you can also take a look to my different post & video
Once you have found the great idea of the year and you want to start implementing your first prototype it is time to choose the right technology. Some would say you should not choose at this step and implement both at end but in my point of view it looks like and economical mistake to do this way. Prototype is to demonstrate and final product. It can request another technology, for sure. But in my point of view the best is to take the right one at the beginning. For most LoRa and Sigfox are both equivalent or for some others one is over the other one, best depends who you ask. In my point of view, if I consider my 2-3 years sigfox experience and my starting experience on LoRa with 1 year background research on it, there is no magic answer. Context of your idea is the keypoint then you have some technical elements to take into account to finalize your decision.
This post will try to illustrate where each of the technology is the best and give you some decision keypoints.
This post is mostly a remember for myself … The formula to get the right antenna size is the following one.
Wavelengh = 300 / FmHz
As an example 300 / 868Mhz = 0,345 m
Then the antenna will be 1/2 wave = 17,28cm or 1/4 wave = 8,64cm
Internet is providing more and more bandwidth to transfer files and files are bigger and bigger. One thing is not changing, it is latency as distance still the same over the time. When a protocol requires acknowledgment between blocks of transfer this latency is limiting the throughput like explained in this post.
The throughput is really different depending on the protocol in use to transfer the file. As I did not found something giving a lot of data to compare the existing protocol, i’ll try to get figures myself and detail here.
Since a couple of day at work I had to investigate on some network issues for an application, it seems that we have a strange ARP configuration that may be the main issue… by the way, I discovered another strange thing where icmp packets sent in burst mode (like a flood) are lost at variable rates. Here is the note on my investigations
piwan.org
PIWan project : Here is a new, quick & dirty project to be done with a raspberry PI : At work we currently have to simulate our application for a worldwide usage. We have really great tools for that but they need expertise and specific campaigns. The purpose of this document is to describe a RPI based solution with two Ethernet cards and some clever command lines to simulate a wan network for developers. The advantage of this solution will be to cost less than 100euros and will be easy to use with the right documentation.
See next pages for implementation details: