Well one is availability, I’ve had gateways like this since October, but also customisation. For example I can plug in a $10 3G USB dongle and have a 3G ready gateway very quickly, I can add Power over Ethernet or a watchdog circuit using the same methods people have been doing on Raspberry Pis and the like for ages.
Also being Linux based its very easy to configure remote access via SSH/VPN or use something like Resin.io for configuration management.
Of course if you don’t need any of this, only want a gateway you can plug in at your home or office then the TTN gateway should be just what you need.
so if you have for example 6 nodes in your house, and they all point to the same frequency, that will work off course, but the gateway will miss a message if several nodes start transmitting at the same time (collision) a real gateway will not miss these packets, up to 8 simultaniously on all frequencies and SF’s.
…but only one per combination of frequency and spreading factor, right? In other words: a full gateway will also not be able to decode 8 messages if they collide (that is: if they use the same frequency and the same SF at the same time). At best, a gateway will then be able to decode one of the messages.
If nodes use different frequencies (channels) or the same frequency but different spreading factors (sub-channels), then a true gateway can indeed receive multiple messages.
Indeed, some single channel gateways can detect a signal on all SFs of a single channel. But once detected, unlike full gateways, they can only decode one at a time.
As an aside: I think you’re confusing Channel Activity Detecting (CAD) with Listen Before Talk (LBT). No single channel gateway I know does LBT, and given the tightly defined receive windows in LoRaWAN, I think no full gateway can use LBT either. They simply need to send when the time has come, regardless if anyone else is sending too.
As lora is capeable of having multiple transmissions at the same time I do not expect this to be a big issue. Also the fact that up and downlink are kind of a “different path” helps.
But not on the same frequency and SF. (Of course, multiple nodes can send on the same frequency and SF, but a gateway will receive at most one.)
Not sure what you mean, and probably a different topic: gateways are half-duplex. So if a gateway transmits, it cannot listen at all That’s one of the reasons why downlinks are so “expensive” for the network.
Full LoRaWAN gateways are able to receive multiple transmissions, not transmit multiple streams at the same time. Also as a gateway has one antenna which is switched from the receivers to the transmitter while transmitting the gateway can’t receive while transmitting.
But then only for broadcasting, right? Given the defined receive windows, a gateway could tell some backend that RX1 is busy, but for RX2 it has no other choice than just send. (Or keep silent and discard the packet.)
No, if local regulations do not allow transmission when another device is sending the only right choice is to discard the packet and tell the back-end it was not sent.
I am following this blog and i am taking away that my one channel gateway LG-01 dragino will not be able to communicate with the nodes of different SFs. Am i right? Please correct if i am wrong.
Can you give insights on how to do it also?
That’s one of the reasons why downlinks are so “expensive” for the network.