If we want that these devices can communicate with each other. 1
They must use the same protocols. 2
And, we are used to representing these protocols on a graph along two axis with the bitrate as the ordinate 3
with bit per second as unit and the abscissa represents the range. 4
There range is the distance at which none device can communicate with another device, 5
or with a gateway. To represent all this protocol, 6
we will compare them with each other and we'll start with a very well known one, which is the Wi-Fi. 7
In terms of range, we're about 100 meters. 8
That is to say that we're in the range of a house or an apartment, considering that there is attenuation 9
in the walls, and regarding the bitrate, we're around 100 megabits per second. 10
But there are many Wi-Fi standards. 11
So we start on relatively low bitrate values, and with the latest standards, we are much more than 12
100 megabits per second. 13
Then, another protocol that is widely used in the world of the Internet of Things is Bluetooth. 14
The Bluetooth, in terms of range, it's much less than the Wi-Fi. 15
We're rather on a range of about ten meters and in terms of bitrate, we're more around one gigabit per second. 16
In Bluetooth, 17
What is interesting is that the latest standards are more focused on low power consumption. 18
That's why Bluetooth has been renamed BLE for Bluetooth Low Energy in the latest generation. 19
Then if we continue on this graph, we can stay in the world of home automation with Zigbee and for 20
Zigbee we're more or less with a range of 100 meters. 21
The difference between Wi-Fi and Zigbee is that the bitrate is lower and we are talking of a value around 22
one kilobits per second. 23
Zigbee is often used in home automation for connecting switches, for example. 24
Then we can use the network operators such as 2G then 3G, 4G and 5G with bitrates from low to very high 25
value under future 5G. 2G and 3G will disappear in the near future. 26
And we expect that the 2G service will be stopped by 2025 and for the 3G will be more around 2028, depending 27
on how fast 5G is deployed. 28
So, now we're going to move on the other part of the graph. 29
And on that part, we are dealing with very low bitrate and very short range. 30
Here we find a very well known protocol, NFC that we use for contactless payment or access authorization, 31
for example. 32
And finally, we will go to the right part of the graph to find protocols with very high range but with 33
very low bitrate. 34
And that's where we'll find LPWAN for Low Power WAN. 35
We will find here, protocol such as Sigfox, LoRa, along with the other operating network like NB-IoT 36
and then LTE-M. 37
So when we look at this graph, there is something that is surprising. 38
It's that if I consider myself as a user, I would like to have both high speed and long range, which 39
means that all the protocol that are on the top right of this diagram would be better than the other. 40
And all those that are the bottom left would be useless. 41
This is obviously not true for several reasons. 42
First, if we take the case of NFC, for example, NFC has a very particular characteristic, which is 43
security, and when you make a contactless payment, you don't want long range at all. 44
On the contrary, you really want the range to be as low as possible for security reasons. 45
So having a short range in that case was a feature that we were looking for. 46
For the others, we could wonder why Bluetooth and Zigbee are interesting when with 5G we can have higher speed 47
and range. 48
Well, in fact, to be able to compare them properly, we should add a new axis here. 49
And this axis is the power consumption. 50
If we look again at NFC, what is the consumption? 51
It's zero. 52
Why is that? 53
Because the card we use, they are powered by a magnetic field. 54
So there is no battery used during the data transmission. 55
And on the other hand, how can we compare Wi-Fi with LPWAN? 56
The first advantage is the range, as we've seen before. 57
But overall, it's again, the power consumption that we need to take into consideration. 58
So that's why we have a whole bunch of protocol here for which we consider that the bitrate was not 59
the most important property. 60
But on the other hand, we wish to have a much higher range and also a very, very low consumption. 61
In that course, we are going to focus mainly on LoRa, this protocol here. 62
And now that we've understood what is LoRa compared to the others. 63
We're going to focus on the frequency band at lower values.