Managing Visited Network NAS Signaling Overrides during Cellular IoT Roaming
Managing visited cellular network NAS overrides requires firmware that accepts assigned timers, prevents aggressive attach retries, and protects battery life.
PSM Power Saving Mode
Meaning
Low-power states in mobile communication standards allow devices to remain registered with the network while disabling their receiver and transmitter circuits. Activating psm power saving mode enables a cellular modem to sleep for extended periods, running into days or weeks, without losing its network attachment. This capability eliminates the need to perform a full registration routine when the device wakes up to send data.
It extends the operating life of battery-powered endpoints.
Operational Cycle
Timer configurations are negotiated between the device and the base station during the initial registration phase. After the negotiated active timer expires, the modem enters psm power saving mode to shut down its internal circuitry while the network reserves its session parameters. This mechanism ensures that the device can wake up instantly to transmit data without undergoing a new attach cycle.
It prevents the network from releasing the registered IP address.
Power Conservation
Modems consume less than three microamps during the sleep phase. This low draw allows devices to operate for multiple years on standard batteries.
Registration Control
The network holds incoming packets and notifications until the device wakes up. The psm power saving mode configuration ensures that the modem is only reachable when it initiates communication with the server. However, this mode does not permit the network to wake up the device on demand or trigger real-time downlink messages.