To calculate the next up-link transmission time, the application layer code is using following statement,
TxDutyCycleTime = APP_TX_DUTYCYCLE + randr (-APP_TX_DUTYCYCLE_RND, APP_TX_DUTYCYCLE_RND);
currently End device is sending the up-link packet (temperature sensor value) after every "TxDutyCycleTime",
requirement is to make "TxDutyCycleTime" configurable to delay the up-link transmission,
can anyone explain why delay is depends on duty cycle?
how to increase the delay between UpLinks after joining?
Beste antwoord door Rick S.Bekijk origineel
Welcome to the IoT Community!
The Duty Cycle was created to guarantee the operation of the network. As we can read in the topic Uplink and Downlink messages and the Duty Cycle, we use the 868 MHz band. The 868 MHz ISM band limits the use of a device up to 1% of the time in the air. LoRaWAN indicates that each time a message is sent in one ISM subband, the device must wait for the remaining time of the work cycle in that band before resending. This means that a sensor that sends a message that lasts 1 second has to be silent for 99 seconds.
Now I have to say that I am not sure if there are any ways to increase the delay between UpLinks after connecting. I will check this with our specialists.
I will come back to you as soon as I have an answer.
thanks for the reply,
can we increase the delay between UpLinks by increasing DutyCycle?
how much dutycycle can be increased in diff bands? or how to calculate it for diff bands?
So for instance if you send a message on SF9, using 250 ms airtime, you then need to be silent in that sub-band for minimum 25 seconds so the duty cycle does not exceed 1%.
But your application may straightaway send another message in another sub-band, should other sub-bands be available, as long as you respect the 1% duty cycle per sub-band.
In addition to the answer of rharte:
KPN is only supporting EU868 and not EU433.
The duty Cycle is deferent between every subband within the EU868.
After joining the Network will sent the delay timer to the device.
After a uplink is possible that the Network will sent a downlink in rx 1 or 2 to change de SF or other mac commands.
That is why the device need to wait before before sending a new uplink.
For example the network can decide to change the timer’s depending of the bandwith of the backhaul or other components of the network.