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We saw in a previous video the comparison between the LoRa modulation and the other protocols of the
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Internet of Things.
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We also saw that the LoRa modulation aims to be long range but with a very low bitrate. For transmission,
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LoRa use free bands.
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And in Europe, free bands mean that there is no need for authorisation.
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And there is also no additional fees.
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I wrote down in the table below a few of these free bands in Europe.
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They are not all mentioned, but these are the main ones.
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And among these free bands, we'll try to see where LoRa is located.
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So first of all, we have the band commonly used for Wi-Fi, Bluetooth BLE and a 2.4 GHz band is
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also used for Zigbee protocol, which I remind you is used for home automation.
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The 5 GHz band is also used for Wi-Fi.
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NFC used for contactless payment is in the 13.56 MHz band, but there is now the 433 MHz potentially
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used by LoRa.
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But of course among a lot of other systems, and in that band there is a very well-known one which is
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the Walkie-Talkie, but obviously not part of the Internet of Things.
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LoRa also uses 868 MHz band with its competitor Sigfox and again many other protocols. Between
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868 and 433,
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how will you make the choice?
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You can choose 433 MHz if you only use the LoRa modulation for your transmission.
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But as soon as you want to use LoRaWAN infrastructure, you don't have a choice because the LoRaWAN
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protocol needs to follow the frequency plan of its network server and it's always 868 MHz in Europe.
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There is also the possibility to use LoRaWAN in the 2.4 GHz band, but it's not so common yet.
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The main advantage of that 2.4 GHz band is that it's a world wide free band, which is not the
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case for 868.
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Remember also that we have to be careful with high frequencies because the higher the frequency, the
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lower the range.
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So, now that we know more about the frequency use, we will try to understand how hundreds, and even thousands
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of communicating devices will be able to transmit information on the same 868 MHz band
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while ensuring that at the end, all messages sent are demodulated without errors.
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And for that, we'll see three techniques that I'm going to explain in the next chapter.