Digi XBee3 XB3M1, User Manual

Page: 131 / 252

Power saving features Airplane mode
Digi XBee3 Cellular LTE-M/NB-IoT Global Smart Modem User Guide 131
Airplane mode
While not technically a sleep mode, Airplane mode is another way of saving power. When set, the
cellular component of the XBee Smart Modem is fully turned off and no access to the cellular network
is performed or possible. Use
AM (Airplane Mode) to configure this mode.
Power Saving Mode (PSM)
To enable PSM, set DO (Device Options) bit 3.
Note For NB-IoT, TCP and SMS support is dependent on the network. Contact your network provider
for details.
Note The cellular module comes out of the PSM low-power state whenever any network activity
occurs, including Remote Manager activity. See Verify the connection between a device and Remote
Manager .
When PSM is enabled, the cellular component spends most of its time in a low power state. In the low
power state the XBee Smart Modem still has an IP address and is registered to the network, which
allows for quick resumption of activity, but is not reachable so cannot receive IP or SMS traffic until it
wakes up. This low power state is used even when taking advantage of XBee sleep features (such as
Pin Sleep or Cyclic Sleep ), rather than powering the cellular component off entirely to ensure
readiness when exiting sleep.
The cellular component wakes to participate in maintaining the network state periodically based on
timers negotiated with the cell tower. It is also triggered to wake up when the user performs any
activity requiring network connectivity such as mobile-originated traffic like sending an SMS or
UDP/TCP traffic. When it wakes up, it spends a short time awake so that it is reachable through the
network at that time and then returns to the low power state.
PSM behavior
Commands exist to influence the PSM behavior when PSM is enabled ( DO bit 3 is set).
Note For NB-IoT, TCP and SMS support is dependent on the network. Contact your network provider
for details.
They are:
n
PA (Requested Active Timer)
n
PU (Requested Tracking Area Update Timer)
PA and PU are the values the XBee Smart Modem requests from the network. The network is free to
assign values other than those which have been requested.
See the LTE-M Deployment Guide from GSMA for a description of what the PSM timers are and what
functions they perform on the network.
Deep Sleep mode
In Deep Sleep mode the cellular component is shut off and the XBee processor is put to sleep.