In 5G wireless communication, PSM stands for Power Saving Mode. PSM is a feature designed to extend the battery life of Internet of Things (IoT) devices by allowing them to enter a low-power state during periods of inactivity. PSM is especially relevant for IoT applications where devices may need to conserve energy while maintaining periodic communication with the network.
Key aspects of PSM in 5G include:
- Objective of PSM:
- The primary objective of PSM is to optimize the power consumption of IoT devices by enabling them to enter a sleep mode during periods of inactivity. This is crucial for extending the battery life of devices that are part of the massive machine-type communication (mMTC) category in 5G.
- Low Power State:
- When a device enters PSM, it transitions into a low-power state where most of its functions are temporarily suspended. This includes turning off unnecessary components and reducing the device’s overall power consumption.
- Periodic Wake-Up:
- Devices in PSM periodically wake up to check for incoming data or signaling from the network. This wake-up interval is configurable, allowing devices to strike a balance between responsiveness and power conservation.
- Mobility Considerations:
- PSM takes into account the mobility patterns of IoT devices. Devices can specify their mobility status to the network, allowing for optimized power management based on whether the device is stationary or in motion.
- Network Support:
- The network supports PSM by managing the communication with devices in a low-power state. When a device wakes up from PSM, it communicates with the network to check for any pending data or commands.
- Timer Values:
- The duration of time that a device spends in PSM is determined by timer values. These values are negotiated between the device and the network during the PSM setup, allowing for flexibility in defining the sleep and wake-up periods.
- Extended Battery Life:
- By allowing devices to spend a significant portion of time in a low-power state, PSM contributes to significantly extending the battery life of IoT devices. This is particularly important for devices deployed in remote or inaccessible locations.
- Support for Various IoT Applications:
- PSM is designed to support various IoT applications with different requirements. For example, devices in agricultural monitoring systems or environmental sensing applications may only need to transmit data periodically, making PSM a suitable power-saving solution.
- UE and Network Coordination:
- PSM involves coordination between the user equipment (UE) and the network. The UE indicates its readiness for PSM, and the network manages the communication with devices in this low-power mode.
- Optimized for mMTC:
- PSM is particularly optimized for mMTC scenarios where a large number of devices coexist, and periodic communication is sufficient for data exchange. It allows networks to efficiently manage the communication needs of a massive number of IoT devices.
- PSM Configuration:
- The configuration of PSM, including the timer values and wake-up intervals, is typically negotiated between the IoT device and the network during the registration process.
- Interworking with Other Power-Saving Mechanisms:
- PSM can work in conjunction with other power-saving mechanisms, such as extended discontinuous reception (eDRX), to further optimize power consumption based on the specific requirements of the IoT application.
In summary, PSM in 5G is a power-saving feature tailored for IoT devices, allowing them to periodically enter a low-power state while remaining responsive to network communication. This enables significant energy savings and extends the operational life of IoT devices in massive machine-type communication scenarios.