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TS001-1.0.4 LoRaWAN® L2 1.0.4 Specification

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LoRaWAN ® L2 1.0.4 Specification © 2020 LoRa Alliance ® Page 72 of 90 The authors reserve the right to change specifications without notice. All end-device ping slots SHALL use the start of the receipt of the preamble of the Class B 2193 beacon as a timing reference. Therefore, the Network Server SHALL take T BeaconDelay into 2194 account when scheduling the Class B downlinks. 2195 13.6 Network Downlink Route Update Requirements 2196 When the Network attempts to communicate with an end-device using a Class B downlink 2197 slot, it SHOULD transmit the downlink from the gateway closest to the end-device when the 2198 most recent uplink was received. Therefore, the Network Server SHOULD keep track of the 2199 approximate position of every Class B end-device. 2200 Whenever a Class B end-device moves and changes cells, it SHALL communicate with the 2201 Network Server in order to update its downlink route. This update is performed simply by 2202 sending a confirmed or unconfirmed uplink, possibly without applicative payload. 2203 The end-device can communicate in accordance with two basic strategies: 2204 Systematic periodic uplink: This is the simplest method as it does not require 2205 demodulation of the gateway-specific field of the beacon. It is applicable only to slowly 2206 moving or stationery end-devices. No requirements are imposed on such periodic uplinks. 2207 Uplink on cell change: The end-device can demodulate the optional gateway-specific field 2208 of the beacon. It detects that the ID of the gateway broadcasting the beacon it demodulates 2209 has changed and sends an uplink. In that case, the end-device SHALL respect a pseudo- 2210 random delay within the range of [0s:120s] between the beacon demodulation and the 2211 uplink transmission to ensure that the uplinks of multiple Class B end-devices entering or 2212 leaving a cell during the same beacon period will not systematically occur at the same time 2213 immediately after the beacon broadcast. 2214 Failure to report a cell change can result in a Class B downlink being temporarily not 2215 operational. 2216

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