LDS01 downlink working sporadically

End Devices (Nodes) Dragino
1

Hello all,

I have some troubles to get the downlink with the Dragino LDS01 working.
The device is connected and is working fine, but for downlinks I often get a rxTimeout.

As a gateway I am using a Dragino LPS8.

The LDS01 is connected, ADR OFF, Fixed DR=5.

AT+CRX1DELAY is set to 5.

e.g. some logging:

LM502:~#
[1173201]***** UpLinkCounter= 21 *****
[1173206]TX on freq 867100000 Hz at DR 5
[1173275]txDone
[1178262]RX on freq 867100000 Hz at DR 5
[1178297]rxTimeOut
[1179267]RX on freq 869525000 Hz at DR 3
[1179310]rxTimeOut

OK+SENT:01

[1233202]***** UpLinkCounter= 22 *****
[1233207]TX on freq 868100000 Hz at DR 5
[1233276]txDone
[1238262]RX on freq 868100000 Hz at DR 5
[1238321]rxDone

OK+SENT:01
[1238330]receive data: rssi = -87, snr = 13, datarate = 5

OK+RECV:00,0B,04,0100003C

[1238471]***** UpLinkCounter= 23 *****
[1238476]TX on freq 868500000 Hz at DR 5
[1238544]txDone
[1243530]RX on freq 868500000 Hz at DR 5
[1243566]rxTimeOut
[1244536]RX on freq 869525000 Hz at DR 3
[1244579]rxTimeOut

OK+SENT:01

[1298472]***** UpLinkCounter= 24 *****
[1298477]TX on freq 867900000 Hz at DR 5
[1298546]txDone
[1303532]RX on freq 867900000 Hz at DR 5
[1303567]rxTimeOut
[1304539]RX on freq 869525000 Hz at DR 3
[1304582]rxTimeOut

OK+SENT:01

Mostly the first downlink after IREBOOT is working an later rather sporadically.
e.g.

LM502:~# AT+IREBOOT=0
OK
[3368]DRAGINO LDS01 Device
[3370]Frequency Band: EU868 v1.2
[3373]OTAA
[3374]DevEui= ***
[3377]class type A
[3378]freq mode intra

[3383]***** UpLinkCounter= 0 *****
[3393]TX on freq 868300000 Hz at DR 5
[3403]Start to Join, method 0, nb_trials:48
[3467]txDone
[8454]RX on freq 868300000 Hz at DR 5
[8488]rxTimeOut
[9460]RX on freq 869525000 Hz at DR 3
[9503]rxTimeOut

[10402]***** UpLinkCounter= 0 *****
[10407]TX on freq 868500000 Hz at DR 5
[10480]txDone
[15467]RX on freq 868500000 Hz at DR 5
[15551]rxDone
+CJOIN:OK
[15562]Joined

[15617]***** UpLinkCounter= 0 *****
[15622]TX on freq 867100000 Hz at DR 5
[15690]txDone
[20677]RX on freq 867100000 Hz at DR 5
[20735]rxDone

OK+SENT:01
[20745]receive data: rssi = -85, snr = 15, datarate = 5

Have you experienced such behaviour or is there some configuration that might be set to get the thing working proper? Or could It be that the message is not directly dequeued for pkt_fwd by the LPS8?

Thanks in advance.

Mark

2

Given that downlinks must be used exceedingly rarely, most of the time you will indeed get an RX timeout for both windows.

The RX window is the opportunity for a downlink, but generally speaking there should not actually be one there. If there usually were, a network with more than a few nodes would rapidly start to jam itself, since a gateway cannot receive any uplinks while it is transmitting a downlink.

3

Thanks for clarification. What about the confirmed transmit type for uplink messages? Considering that the RX window is an “opportunity” this would lead to repeated uplink messages in worst case “nbtrials” times when no confirm package has been recieved by the node.

4

You can’t really use confirmed uplink on TTN, as you’d quickly exceed your 10 downlinks per day limit if each uplink were acked.

Make sure your node is set to transmit in unconfirmed mode.