Issue link: https://read.uberflip.com/i/1428395
LoRaWAN ® L2 1.0.4 Specification © 2020 LoRa Alliance ® Page 52 of 90 The authors reserve the right to change specifications without notice. Class B is enabled by the following process: 1649 The end-device application requests the LoRaWAN layer to enable Class B mode. The 1650 LoRaWAN layer in the end-device searches for a beacon. To accelerate beacon discovery, 1651 the LoRaWAN layer MAY use the DeviceTimeReq MAC command. 1652 Once the end-device has found a beacon, it MAY enable Class B mode. 1653 Once Class B is enabled, the MAC layer SHALL set to 1 the ClassB bit of the FCtrl field 1654 of every uplink frame transmitted to remain Class B-enabled. This bit signals to the server 1655 that the end-device has enabled Class B. 1656 The MAC layer SHOULD autonomously schedule a reception slot for each beacon and each 1657 ping slot. The end-device SHALL take into account the maximum possible clock drift in the 1658 scheduling of the beacon reception slot and ping slots. When a downlink is successfully 1659 demodulated during a ping slot, it SHALL be processed similarly to a downlink as described 1660 in the LoRaWAN Class A specification. 1661 A mobile end-device SHOULD periodically inform the Network Server of its location to 1662 update the downlink route. This is done by transmitting a normal (possibly empty) 1663 unconfirmed or confirmed uplink. The end-device LoRaWAN layer SHALL appropriately set 1664 the ClassB bit to 1 in the frame's FCtrl field. This can be done more efficiently if the end- 1665 device detects that it is moving by analyzing the beacon content. In that case, to avoid 1666 systematic uplink collisions, the end-device SHALL apply a random delay (as defined in 1667 Section 13.6) between having received the beacon and transmitting the uplink. 1668 During any Class A downlink, the Network Server MAY change the end-device's ping-slot 1669 downlink frequency or data rate by sending a PingSlotChannelReq MAC command and 1670 receiving the corresponding PingSlotChannelAns. 1671 The end-device MAY change the periodicity of its ping slots at any time. To do so, it SHALL 1672 temporarily disable Class B operation (unset ClassB bit in its uplink frames) and send a 1673 PingSlotInfoReq to the Network Server. Once this command is acknowledged, the end- 1674 device MAY re-enable Class B operation with the new ping-slot periodicity. 1675 If no beacon has been received for a given period (as defined in Section 12.2), 1676 synchronization with the Network is lost. The end-device LoRaWAN layer SHALL stop 1677 setting the ClassB bit in all uplinks, which informs the Network Server that the end-device 1678 has disabled Class B mode. 1679 1680