Rak4630 is not receiving my downlink packet

WisBlock
#1

Title: Issue with Direct Downlink Transmission from WM1302 Gateway

Hello RAK Community,

I hope this message finds you well. I’m currently working with the WM1302 gateway and attempting to send downlink packets directly to end nodes without using a network server. I’ve encountered an issue where although the data seems to be transmitted from the module, it’s not being received at the node end.

Details:

  • Gateway Model: WM1302
  • Issue Summary: Unable to receive downlink messages on end nodes.
  • Scenario: Attempting to bypass the network server for direct downlink transmission.
  • Observations: The code for transmitting data from the gateway appears to be working without errors.

Questions:

  1. Is it technically feasible to send downlink messages directly from the gateway without using a network server?
  2. Are there specific considerations or configurations that need to be addressed for direct downlink transmission?
  3. Could security concerns be a factor in the lack of reception on the node end?

I appreciate any insights, guidance, or suggestions the community can provide to help resolve this issue. Thank you in advance for your assistance.

Best regards, Stalin T John

#2

Welcome to the forum @stalin

Unless your Gateway is running the LoRaWAN server as well (like you can do on our WisGate Edge gateways), you cannot send a downlink to the node from the gateway. The gateway doesn’t know the encryption keys.
Downlinks can be only initiated from a LoRaWAN server.

#3

I received the data in the gateway (wm1302) after transmitting it from the end node (rak4630).I want to send data back to the end nodes from the gateway; is this possible using Lora wan communication? I have a code for transmitting data over a gateway. Will be attached this to.

https://github.com/will127534/SX1302_Arduino_Library/tree/main/examples/test_loragw_tx

#4

Not sure what you actually want to do.
The code you linked to is sending LoRa (NOT LoRaWAN) packets over the SX1302. To be able to receive these packets, you have to set your RAK4630 into LoRa P2P mode, set the same BW/SF/CR/… than on the WM1302. Then you have to set the RAK460 into RX mode and you should be able to receive the data.

But all of that has nothing to do with LoRaWAN. This is just sending packets over LoRa without using the LoRaWAN protocol.

#5

yes, i tried with the p2p receiver code in rak4630 but not able to receiving https://github.com/RAKWireless/WisBlock/tree/master/examples/RAK4630/communications/LoRa/LoRaP2P

Screenshot 2023-11-21 145126
Screenshot 2023-11-21 1451261830×784 168 KB

#7

Are you sure the coding rate, preamble length and IQ inversion are set the same. I don’t see these settings in the WM1302 settings.

image
image1545×481 234 KB

Can you check (e.g. with a SDR) if the WM1302 is actually sending something?

#8

uint16_t preamble = 8;
pkt.coderate = CR_LORA_4_5;
bool invert_pol = false;
yes ,there are the values mentioned in the gateway code.

(https://github.com/will127534/SX1302_Arduino_Library/tree/main/examples/test_loragw_tx)
#9

Are you sure the WM1302 is sending the packets?
I see errors in the log of the WM1302:

image
image1638×714 112 KB

#10

Yes, it is transmitting the packets, but just for ten times before the gateway is forcibly closed. The actual log that has been attached to this.

INFO: selecting TX Gain LUT index 0
INFO: Applying IQ offset (i:0, q:0)
Setting LoRa syncword 0x34
Disable Fine Sync
Low datarate optimization DISABLED
INFO: tx_start_delay=47413 (48000, radio_bw_delay=19, filter_delay=504, modem_delay=64)
Start Tx: Freq:865000000 SF7 size:20 preamb:8
TX done
INFO: selecting TX Gain LUT index 0
INFO: Applying IQ offset (i:0, q:0)
Setting LoRa syncword 0x34
Disable Fine Sync
Low datarate optimization DISABLED
INFO: tx_start_delay=47413 (48000, radio_bw_delay=19, filter_delay=504, modem_delay=64)
Start Tx: Freq:865000000 SF7 size:20 preamb:8
in 0
ERROR: sx1302_tx_abort: TIMEOUT on TX abort
WARNING: failed to get abort TX on chain

#11

Then I am not sure what the problem is. I have RAK4630 working in P2P mode in a Mesh network without problems.
I have no experience with the WM1302, so I can’t help fixing it.

#12

Run a quick test with two RAK4631’s and both sides are receiving the packet from each other.

image
image1405×1000 106 KB

#13

Thank you so much for your feedback :+1:

#14

https://github.com/will127534/SX1302_Arduino_Library/tree/main/examples/test_loragw_tx
I think its a lorawan based code, can you make sure.

#15

https://github.com/RAKWireless/WisBlock/blob/master/examples/RAK4630/communications/LoRa/LoRaWAN/LoRaWAN_OTAA_ABP/LoRaWAN_OTAA_ABP.ino
is this lorawan based code? inside the code how the lorawan_rx_handler function is working,does it need any network server support and by using any lorawan transmit code is it possible to receive data on RAK.

#16

This one:

Is for a gateway, not for an end node

This one is for a LoRaWAN application. You need a gateway and setup the device on a LoRaWAN server

#17

yes,i have the gateway ,so i need to receive data from that gateway baseband chip sx1302.for that what are the thinks need to look.here in the rak code lorawan_rx_handler function is there how can i get to call this function.I have a sender code that sends data from gateway https://github.com/will127534/SX1302_Arduino_Library/tree/main/examples/test_loragw_tx

#18

The code LoRaWAN_OTAA_ABP.ino is for LoRaWAN, not for LoRa P2P it cannot receive LoRa P2P packets.

If you are trying to send a data packet over LoRa P2P then you need to run on the RAK4620 the LoRa P2P code LoRaP2P

And, as I explained already, the P2P parameters on both sides have to be identical.

I have no idea whether this test_loragw_tx.ino code is sending P2P packets or simulates LoRaWAN packets. Maybe you need to clarify this first with the writers of that code.