how can i resend message until receive ack? (when channel is busy))

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  • January 23, 2020 at 2:47 am #30184
    tkddlf4209@gmail.com
    Participant

    In API Doc
    AT+ACK command means below

    The maximum number of times the end device tries to retransmit an unacknowledged packet. Options are from 1
    to 8. (isn’t acknowledged not unacknowledged?)

    If the channel is busy, the AT + ACK parameter is changed to 1-8 to resend the message, but the message transmission ends immediately with the message “channel is busy”.

    How do I retransmit until I receive an ACK message when the channel is busy?

    thanks

    January 23, 2020 at 7:52 am #30189
    Jason Reiss
    Keymaster

    What Channel Plan is being used?
    The “channel is busy” would only be expected if LBT is enabled.

    retransmit an unacknowledged packet

    This is correct, if the packet was acknowledged there would be no retransmission. Perhaps you are confusing with Confirmed/Unconfirmed Uplinks.

    January 29, 2020 at 10:12 pm #30210
    tkddlf4209@gmail.com
    Participant

    then, Is it right to disable the LBT option to retrasmit messages when this channel is busy? (with AT+ACK=1 or more)

    I have one more question

    i using Lora Gateway made in RAK
    Lora packet Logger in RAK gateway show uplink & downlink(ACK) message correctly when i send AT+SEND message , But not receive ACK Message in Multitech Lora Module sometimes why is that? (is not channel busy)

    so If AT+ACK set to 2 or more
    Although the ACK message is sent from the ARK Lora gateway to the downlink, the Multitech module does not recognize the ACK and resends the uplink message according to the number of retransmissions set by the AT + ACK option.

    I tried to increase the Recv time to 3 seconds to receive the ACK message, but the phenomenon still occurs.

    * RAK Lora Gateway Packet Logger INFO (Uplink & Downlink(ACK))
    – Uplink
    {
    “fType”: 0,
    “freq”: 922900000,
    “chan”: 4,
    “tmst”: 1200072524,
    “rfch”: 1,
    “stat”: 1,
    “rssi”: -125,
    “size”: 62,
    “modu”: “LORA”,
    “datr”: “SF12BW125”,
    “codr”: “4/5”,
    “lsnr”: -18.8,
    “data”: “gKCZGgCgRAABmtJznW1eIs1klm8fsMorz2n6MCRDn/bKKv8UhhnDw7qHBbQPq9lz9NOOdoEMzqTGQz3OAHc=”
    }{
    “MHDR”: {
    “MType”: “Confirmed Data Up”,
    “RFU”: 0,
    “Major”: 0
    },
    “MACPayload”: {
    “FHDR”: {
    “DevAddr”: “001A99A0”,
    “FCtrl”: {
    “ADR”: true,
    “ADRACKReq”: false,
    “ClassB”: false,
    “ACK”: true,
    “FOptsLen”: 0
    },
    “FCnt”: 68
    },
    “FPort”: 1,
    “FRMPayload”: “01 9A D2 73 9D 6D 5E 22 CD 64 96 6F 1F B0 CA 2B CF 69 FA 30 24 43 9F F6 CA 2A FF 14 86 19 C3 C3 BA 87 05 B4 0F AB D9 73 F4 D3 8E 76 81 0C CE A4 C6 ”
    },
    “MIC”: “3DCE0077”
    }

    – downlink
    {
    “fType”: 0,
    “freq”: 922900000,
    “mode”: “timerstamped”,
    “tmst”: 1201072508,
    “rfch”: 0,
    “powe”: 23,
    “prea”: 8,
    “ncrc”: false,
    “modu”: “LORA”,
    “datr”: “SF12BW125”,
    “codr”: “4/5”,
    “ipol”: true,
    “size”: 18,
    “data”: “oKCZGgCwNQABWSVBpbjK6J0w”
    }{
    “MHDR”: {
    “MType”: “Confirmed Data Down”,
    “RFU”: 0,
    “Major”: 0
    },
    “MACPayload”: {
    “FHDR”: {
    “DevAddr”: “001A99A0”,
    “FCtrl”: {
    “ADR”: true,
    “RFU”: 0,
    “FPending”: true,
    “ACK”: true,
    “FOptsLen”: 0
    },
    “FCnt”: 53
    },
    “FPort”: 1,
    “FRMPayload”: “01 59 25 41 A5 ”
    },
    “MIC”: “CAE89D30”
    }

    Summary: The RAK Lora Gateway logs the downlink ACK message for the uplink, but the Multitech Lora Module often fails to receive the ACK.

    Lora Module same as manufacturer (RAK) works without problem

    Is there an option to change with AT command?

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