Issue link: https://read.uberflip.com/i/1539840
Developing LoRaWAN Devices Technical Recommendation TR007-1.1 ©2021-2025 LoRa Alliance ® Page 17 of 28 The authors reserve the right to change documents without notice. can trigger a catastrophic, self-persisting, radio network overload situation. 544 Note: A typical example of such an uplink frame is a Join-Request, if the 545 implementation of a group of end-devices decides to reset the MAC layer, in the case 546 of a network outage. The entire group of end-devices will start broadcasting Join- 547 Request uplinks and will stop only upon receiving a Join-Accept from the network. 548 For those frame retransmissions, the interval between the end of the RX2 slot and the 549 next uplink retransmission SHALL be random and follow a different sequence for every 550 end-device (for example using a pseudo-random generator seeded with the end- 551 device's address). The transmission duty cycle of such a frame SHALL respect local 552 regulations and the following limits, whichever is more constraining: 553 Aggregated during the first hour following power-up or reset T 0 < t < T 0+1 Transmit time < 36 s per hour 1% duty cycle Aggregated during the next 10 hours T 0+1 < t < T 0+11 Transmit time < 36 s per 10 h 0.1% duty cycle After the first 11 hours, aggregated over 24 hours, where N refers to days, starting at 0 T 0+11 + N × (24 hours/day) < t < T 0 + 35 + N × (24 hours/day), N ≥ 0 Transmit time < 8.7 s per 24 h 0.01% duty cycle Additional back-off algorithms MAY be implemented within each period described above. 554 4.9 Discontinuing Retransmissions 555 4.9.1 Description 556 End-devices will sometimes issue retransmissions (uplink messages with the same content 557 and frame counter as the previous message), to improve message delivery. This is controlled 558 via the NbTrans parameter. Any reception by the end-device in a Class A window explicitly 559 indicates that the message has been received by the network and no additional 560 retransmissions of the same frame counter are needed. 561 4.9.2 Recommended Practice 562 When an end-device retransmits an uplink message multiple times because of NbTrans > 1, 563 it SHALL stop retransmitting the message as soon as it has received any valid Class A 564 downlink. This behavior is fully specified and REQUIRED by LoRaWAN 1.0.4+. 565