ABP mDot downlink issues?

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  • July 24, 2017 at 5:35 pm #20305
    fleebag
    Participant

    I was wondering if anyone has gotten the mDot to successfully receive an ACK or Downlink packet?? My setup is:

    * the mDot (US915) with
    * a mirakonta-like gateway and
    * the brocaar’s gateway bridge, loraserver, and lora-app-server.

    On the Lora server, I’m setting the RX1 datarate offset to “10,” and the RX2 datarate to “8”.

    I’m seeing the downlink get transmitted by the gateway (I’m observing the radio bursts with GQRX) but the mDot doesn’t show that it’s received the data. For both the ACK and the recv() function, it returns a “-5” error code (Operation timed out).

    Is there anything else I should consider when configuring the mDot or the LoraServer for Downlink communications?

    Thanks!

    July 25, 2017 at 7:48 am #20308
    Jason Reiss
    Keymaster

    Try rx1 offset of 0.

    Uplink frequency and datarate will determine the downlink response parameters. A DR Offset of 10 is outside of allowed values in LoRaWAN, range is 0-3.

    July 25, 2017 at 12:09 pm #20336
    fleebag
    Participant

    Hi Jason! Thanks for the response!

    I changed that recently from 0 to 10 because I interpreted a TTN documented data rates for US915 up-to-downlink was pretty much read as ten… but I misread it, and found the actual datarate offsets you mentioned in the Regional Parameters. I’ll change it back! 🙂

    Unfortunately, the thing is that before I changed it to 10, it still had an “Operation Timed out” with the offset of zero..? (And I just tested it now, and I’m still not receiving ACKs or downlinks in either RX1 or RX2)

    I’m assuming that the rx2 rate of 8 is correct, according to section 2.2.7 of the LoraWan Regional Parameters (ver1.0-20161012)? (btw, the rx2 datarate was the same… I tried it at 0 for a while, and then recently changed it to 8 and the mDot didn’t receive ACKs or data in either datarate…)

    Thanks!

    • This reply was modified 7 years, 9 months ago by fleebag. Reason: clarity
    • This reply was modified 7 years, 9 months ago by fleebag. Reason: added explanation of rx2 DR
    July 25, 2017 at 1:40 pm #20344
    fleebag
    Participant

    Okay, looking at Lora.h the default for RX2 is 0, but I’m still having issues with ACKs and Downlinks. 🙁

    July 25, 2017 at 1:53 pm #20345
    Jason Reiss
    Keymaster

    Did you call setPublicNetwork(true) ?

    July 25, 2017 at 2:53 pm #20346
    fleebag
    Participant

    I tried it just now. Funny because it goes from public to private to back to public (when I call the function)…

    [INFO] Initialize channels…
    [INFO] Initialize datarates…
    [INFO] Set radio to Public Mode
    [INFO] mDot Ready
    [INFO] mbed-os library version: 139
    [INFO] defaulting Dot configuration
    [INFO] changing network join mode to MANUAL
    [INFO] Initialize channels…
    [INFO] Initialize datarates…
    [INFO] Set radio to Private Mode
    [INFO] Set radio to Public Mode
    [INFO] Initialize channels…
    [INFO] Initialize datarates…

    Unfortunately the ACKs/downlinks are still not being received. :-/

    July 25, 2017 at 4:59 pm #20349
    Jason Reiss
    Keymaster

    Increase the log level to 6 on mdot and you will see tx and rx frequencies and datarates used for windows.

    July 25, 2017 at 8:40 pm #20350
    fleebag
    Participant

    Ah ok. I changed to TRACE_LEVEL.

    [INFO] Configure radio for TX
    [DEBUG] Session pwr: 20 ant: 3 max: 30
    [DEBUG] Radio Power index: 20 output: 19 total: 22
    [DEBUG] TX PWR: 20 DR: 0 SF: 10 BW: 0 CR: 1 PL: 8 CRC: 1 IQ: 0
    [INFO] Configure radio for TX
    [DEBUG] Session pwr: 20 ant: 3 max: 30
    [DEBUG] Radio Power index: 20 output: 19 total: 22
    [DEBUG] TX PWR: 20 DR: 0 SF: 10 BW: 0 CR: 1 PL: 8 CRC: 1 IQ: 0
    [DEBUG] mDotEvent – TxDone
    [TRACE] Event: OK
    [TRACE] Flags Tx: 1 Rx: 0 RxData: 0 RxSlot: 0 LinkCheck: 0 JoinAccept: 0
    [TRACE] Info: Status: 0 ACK: 0 Retries: 0 TxDR: 0 RxPort: 0 RxSize: 0 RSSI: 0 SNR:0
    [TRACE] RX1 on freq: 924500000
    [TRACE] RX DR: 10 SF: 10 BW: 2 CR: 1 PL: 8 STO: 12 CRC: 1 IQ: 1
    [TRACE] Stats: Up: 296 Down: 0 DupTx: 0 CRC Errors: 0
    [INFO] Rx Window 1
    [DEBUG] mDotEvent – MissedAck : retries 0
    [TRACE] Event: RX_TIMEOUT
    [TRACE] Flags Tx: 0 Rx: 0 RxData: 0 RxSlot: 1 LinkCheck: 0 JoinAccept: 0
    [TRACE] Info: Status: 3 ACK: 0 Retries: 0 TxDR: 0 RxPort: 0 RxSize: 0 RSSI: 0 SNR:0
    [TRACE] RX2 on freq: 923300000
    [TRACE] RX DR: 8 SF: 12 BW: 2 CR: 1 PL: 8 STO: 12 CRC: 1 IQ: 1
    [TRACE] Stats: Up: 296 Down: 0 DupTx: 0 CRC Errors: 0
    [INFO] Rx Window 2
    [DEBUG] mDotEvent – MissedAck : retries 0
    [TRACE] Event: RX_TIMEOUT
    [TRACE] Flags Tx: 0 Rx: 0 RxData: 0 RxSlot: 2 LinkCheck: 0 JoinAccept: 0
    [TRACE] Info: Status: 3 ACK: 0 Retries: 0 TxDR: 0 RxPort: 0 RxSize: 0 RSSI: 0 SNR:0
    [ERROR] ACK not received
    [ERROR] failed to send data to gateway [-5][Operation Timed Out]
    [INFO] Uplink frame counter: 296
    [ERROR] No packet received
    [ERROR] failed to recv: [-5][Operation Timed Out]
    [INFO] Downlink frame counter: 0
    [INFO] sleeping 10s or until interrupt on DIO7 pin
    [INFO] application will resume after waking up�[INFO] light: 36525 [0x8EAD]
    [DEBUG] Send with tx timeout 5000
    [INFO] Preparing frame

    So I bumped the DR for RX2 back up to 8.
    Above is what showed up during the time in which my downlink data de-queued from the server… I’m unfortunately still getting the Operation Timed Out errors for both downlinks and acks…argh.

    August 1, 2017 at 9:36 pm #20498
    Robert Rodriguez
    Participant

    I am experiencing this same issue. Lost ACKS and Timeouts seemed to have started consistently happening out of the blue. I have tried several xdots with the same results. Even using AT commands.

    August 2, 2017 at 9:55 am #20509
    fleebag
    Participant

    I’m also going to post a link to an mbed forum post. It didn’t solve my problem, but it’s where I first learned about using recv().

    The linked code at the end applies to OTAA and apparently an older version of mbed OS, so it didn’t really plug straight into my example code.

    • This reply was modified 7 years, 9 months ago by fleebag. Reason: Text after the href disappeared. Moved to make it visible
    • This reply was modified 7 years, 9 months ago by fleebag. Reason: Link disappeared, rearranging to try to get everything to show
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    August 9, 2017 at 7:13 pm #20582
    fleebag
    Participant

    I’ve gotten Arduino Nano with LMiC to read my downlinks… so I’m back to wrestling with the mDot.

    Currently the mDot’s rx2 is SF12 while the Loraserver is sending out RX2 at SF10.

    Anyone know how to change RX2’s expected spread factor?

    August 9, 2017 at 7:26 pm #20583
    Jason Reiss
    Keymaster

    At+MAC=CMD

    Send a mac command from server or inject mac command to change sessio n rx param per lorawan.

    August 9, 2017 at 7:40 pm #20584
    fleebag
    Participant

    Ok thanks!

    Also, I just reset my Downlink frame counter to zero, even though loraserver’s uplink counter reset when I reset the mDot with an iteration of my firmware.
    I also set the Datarate in the backend to 8 (SF12BW500). (I’ve switched between 8 and zero several times already)

    And it’s finally switched over to sending txpks at 12/500 to my gateway.

    So maybe Robert Rodriguez should look into resetting the back end’s downlink counter?

    Jason, thank you so much for your attention to this thread!

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