15.4 Beaconing precise timing

1. The beacon is sent every 128 seconds starting at 00:00:00 Coordinated Universal Time
2. (UTC), 1 January 1970 plus NwkID plus TBeaconDelay. Therefore the beacon is sent at
3. B_T = k 128 + *NwkID + TBeaconDelay
4. seconds after 00:00:00 Coordinated Universal Time (UTC), 1 January 1970
5. wherebyk is the smallest integer for which
6. k 128 +*NwkID>T
7. whereby
8. T = seconds since 00:00:00 Coordinated Universal Time (UTC), 1 January 1970.

1. Whereby TBeaconDelay is a network specific delay in the [0:50] ms range.
2. TBeaconDelay may vary from one network to another and is meant to allow a slight
3. transmission delay of the gateways. TBeaconDelay must be the same for all gateways of a
4. given network. TBeaconDelay must be smaller than 50 ms. All end-devices ping slots use
5. the beacon transmission time as a timing reference, therefore the network server as to take
6. TBeaconDelay into account when scheduling the class B downlinks.

30