For countries like Korea, LBT is required. All devices must use LBT. It seems like sx1301 + sx1272 chip + FPGA are required to support LBT on a gateway.
I’d like to know if The Things Gateway supports LBT.
@arjanvanb, I’ve read your comment before I posted my question on the forum. LoRaWAN may not mandate LBT but Korean regulation mandates LBT. The current KR920-923 ISM band regulation exclusively uses LBT to maximize the MACPayload.
It’s why I need LBT support if I wanted to use any device (including gateways) in Korea.
I wondering about “use LBT to maximize the MACPayload”.
Regardless of the size of the data i want to send, LBT is just listening channel before data sent.
Q1. If i use LBT and check out channel is free, can i sent maximum length of payload ??
Q2. At this time, Why LoRaWAN devices does not use LBT or not implemented yet??.
In wireless sensor network, many nodes use LBT or CSMA/CA to avoid collision which has power consumption but do that.
In which region? And how are you going to meet RX windows timing requirement?
This functionality was removed from Semtech reference sources more than year ago. First, it turns LoRa from Long Range to Short Range. Second, it’s almost useless due to “hidden node problem”.
i have another question about RX windows and gateway.
Q1. After Node transmit(Tx), gateway will transmit ACK or data(If it presence) to RX1 window. But if there is a collision at RX1 window, how gateway know this and the gateway sends data to RX2 window?
It might be able to detect a collision, but even if no collision occurred then it would not know if the node received the data.
It’s not like RX2 is used when RX1 fails: just one window is selected by the backend (it’s not up to a gateway to decide), and TTN prefers RX2 so probably skips RX1 altogether.
So, if a node requests an ACK for an uplink but does not receive it, or if an application requests an ACK for a downlink but does not get it, then they need to decide for themselves to try again.