Meaning
Scheduled time interval defines when a Low Power Wide Area Network device is permitted to send data to the base station. The lte-m transmit window is synchronized with the network clock to ensure that multiple devices do not attempt to access the radio medium at the same time. This timing manages the half duplex nature of many IoT modules.
Timing Precision
The device must wake up early to decode the frame number. Within the lte-m transmit window, the terminal aligns its bursts with the resource blocks. Any drift in the oscillator can cause the transmission to overlap with other slots.
This leads to collisions.
Energy Consumption
Restricting the transmission to a specific period allows the device to stay in a deep sleep state for the majority of the time. Because the lte-m transmit window is relatively short, the peak current consumption is concentrated into a brief burst. This behavior is ideal for devices powered by small batteries or energy harvesting systems that need to recover charge between events.
The duty cycle remains very low.
Latency Impact
Data packets are buffered in the local memory until the next available slot. If the lte-m transmit window is infrequent, the delay between a sensor event and the cloud update increases significantly. This trade off between power efficiency and responsiveness is a central consideration when configuring the extended discontinuous reception settings.
