13.1 Definitions

1. To operate successfully in Class B the end-device must open reception slots at precise
2. instants relative to the infrastructure beacon. This section defines the required timing.
3. The interval between the start of two successive beacons is called the beacon period. The
4. beacon frame transmission is aligned with the beginning of the BEACON_RESERVED
5. interval. Each beacon is preceded by a guard time interval where no ping slot can be placed.
6. The length of the guard interval corresponds to the time on air of the longest allowed frame.
7. This is to insure that a downlink initiated during a ping slot just before the guard time will
8. always have time to complete without colliding with the beacon transmission. The usable
9. time interval for ping slot therefore spans from the end of the beacon reserved time interval
10. to the beginning of the next beacon guard interval.

1. The beacon frame time on air is actually much shorter than the beacon reserved time
2. interval to allow appending network management broadcast frames in the future.
3. The beacon window interval is divided into 2¹² = 4096 ping slots of 30 ms each numbered
4. from 0 to 4095.
5. An end-device using the slot number N must turn on its receiver exactly Ton seconds after
6. the start of the beacon where:

22 Ton = beacon___reserved + N * 30 ms

©2016 LoRa™ Alliance Page 45 of 70

The authors reserve the right to change specifications without notice.

LoRaWAN Specification