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We're going to focus here on the LoRa transmission from one end device to a gateway.
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For the moment, you can consider the gateway as a simple LoRa receiver, and I picked up randomly one
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of the receiver frame on the gateway logs.
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What kind of information do we have here?
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First of all, we can check that we use the 868 megahertz band on a specific channel, which is in this
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case, 867.9.
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There is also the spreading factor.
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The one used for this packet is SF12.
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And finally there is the data size of 52 bytes.
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This is simply the payload carried by the lower frame.
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If I click on this packet, I have some additional details.
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First, I see that this device is operated by Bouygues Telecom.
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It doesn't belong to me.
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And yet I received the packet on my gateway.
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Yes, my gateway is the LoRa receiver
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And it receives every LoRaWAN frames in its range.
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It will be up to the server to verify if it will accept it or not, but we will see that later.
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I have also the detail of the payload.
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However, it's obviously encrypted and I can't understand it because of course I don't have the corresponding
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encryption keys.
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If I go into the details of the transmission, I have information that is related to the radio frequency
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transmission.
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I find that the received power of my gateway is -121 dBm.
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This is the RSSI.
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I also have the information that the signal over noise ratio on my gateway is minus 2 dB and again,
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my gateway reminds me the channel used: 867.9 megahertz.
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There are also other information that we will have to explain: "air time", "bandwidth", "frame counter", "device adress"
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and "CR" for Coding Rate.
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Some information are part of the LoRa modulation and some others are part of the LoRaWAN protocol.
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But again, no worries.
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We'll take it step by step.