Issue link: https://read.uberflip.com/i/1539840
Developing LoRaWAN Devices Technical Recommendation TR007-1.1 ©2021-2025 LoRa Alliance ® Page 12 of 28 The authors reserve the right to change documents without notice. the 500 kHz channels. For AU915, these Join Requests SHOULD be sent at DR2 and DR6 354 respectively. Join Request attempts SHOULD select one of the 8 channel banks and then 355 randomly select a channel within that channel bank. A channel from each distinct channel 356 bank SHOULD be used without repeating bank usage. After a single channel has been 357 attempted from each channel bank, another cycle of attempts SHOULD be made using one 358 of the remaining seven unused channels from each bank, again in random fashion. This 359 continues until all channels in each bank are used once in a cycle of 72 Join Request attempts. 360 4.3 Detecting Loss of Network Connectivity 361 4.3.1 Description 362 An end-device may lose connectivity with a network for a variety of reasons: 363 1 The end-device has moved and is no longer in coverage, either while using its current 364 radio frequency (RF) configuration or regardless of its RF configuration. 365 2 The network conditions have changed (new interference, gateways have been 366 reconfigured, etc.), resulting in loss of coverage. 367 3 The network has lost state synchronicity with the end-device (session keys were lost, 368 frame counters are out-of-sync, etc.). 369 4 The network operator has ceased operating the network. 370 The end-device may use several techniques to detect and mitigate these conditions. 371 4.3.2 Recommended Practice 372 End-devices with Adaptive Data Rate (ADR) enabled (both the end-device and the network 373 assert the ADR bit), SHALL follow the ADR back-off procedure described in the LoRaWAN 374 Link Layer specification. This procedure uses ADRAckReq and the receipt of Class A 375 downlinks to test connectivity and will gradually restore the end-device's default ADR 376 configurations in a stepwise manner. Ultimately the end-device is configured to use all default 377 channels at maximum transmit power and lowest data rate. For fixed channel plan regions, 378 this requires that ALL channels are enabled. For dynamic plan regions, this requires that the 379 default (or join) channels are enabled in addition to any dynamically configured channels. 380 ADRAckReq remains set after returning to default ADR configuration. An additional 381 ADR_ACK_LIMIT uplinks sent with no Class A downlink received is strongly 382 RECOMMENDED. When no Class A downlinks have been received after that extended 383 period, the end-device MAY consider network connectivity to be lost. 384 End-devices not being controlled through ADR MAY test network connectivity in a similar 385 manner but SHALL use a technique other than ADRAckReq to request a downlink from the 386 network. If these methods are not part of the end-device's normal operating mode, it is 387 RECOMMENDED that they be used only occasionally (in the same manner ADRAckReq is 388 used). End-devices that employ these methods as part of their normal operation, but are also 389 controlled through ADR, MAY use these techniques to augment the ADRAckReq based back- 390 off. Several examples of such techniques are: 391 1 Send a confirmed uplink (which may contain no application payload), to request an 392 acknowledgement from the network. 393