Low Power Synchronization Signal for IoT Terminal Devices
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Solution Overview
Problem
Power-limited devices, such as IoT devices and wearable devices, face significant power consumption even in RRC idle/inactive states due to periodic paging monitoring and measurement.
Innovation Solution
The implementation of a low power (LP) synchronization signal (LP-SS) and wake-up signal (LP-WUS) that utilize amplitude modulation sequences, such as OOK, to facilitate synchronization and wake-up operations in low power modes, reducing power consumption and maintaining communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the terminal device enters RRC idle/inactive state to reduce power consumption, then power consumption is reduced, but periodic paging monitoring and measurement still consume considerable power
Solution Approach 1:
The patent segments the synchronization signal into two parts: a first synchronization signal for initial synchronization and a second synchronization signal for maintaining synchronization in RRC idle/inactive state. This segmentation allows the terminal to use different signaling mechanisms for different states, reducing power consumption while maintaining communication reliability.
Solution Approach 2:
The patent introduces a wake-up signal as an intermediary mechanism between the network and terminal in RRC idle/inactive state. The wake-up signal triggers the terminal to wake up from low-power mode only when necessary, reducing unnecessary paging monitoring and measurement power consumption while ensuring reliable communication when needed.
2Reliability
If the terminal device monitors paging periodically to maintain communication, then communication reliability is maintained, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by having the network device transmit the wake-up signal before the terminal needs to wake up for paging monitoring. The terminal can detect the wake-up signal in advance and prepare for wake-up, allowing it to remain in low-power mode longer and only wake up when actually needed, thus reducing overall power consumption while maintaining communication reliability.
Solution Approach 2:
The patent uses periodic action through the periodic transmission of synchronization signals and wake-up signals. The first synchronization signal is transmitted periodically to maintain terminal synchronization, and the wake-up signal is transmitted periodically to alert the terminal when paging is available. This periodic mechanism ensures reliable communication while allowing the terminal to stay in low-power mode between periods.
3Use of energy by moving object
If the terminal device uses low power mode to save energy, then power consumption is reduced, but synchronization with the network may be lost
Solution Approach 1:
The patent ensures continuity of useful action by having the network device continuously transmit the second synchronization signal while the terminal is in RRC idle/inactive state. This continuous synchronization signal transmission maintains the terminal's time and frequency synchronization with the network without requiring the terminal to be fully active, thus preserving synchronization precision while maintaining low power consumption.
Solution Approach 2:
The patent implements feedback through the wake-up signal mechanism, where the network device sends feedback information about available paging or communication opportunities to the terminal in low-power mode. This feedback allows the terminal to maintain synchronization awareness and wake up appropriately without continuous high-power monitoring, balancing synchronization precision with power savings.
Data Source
AI summary
Example embodiments of the present disclosure relate to methods, devices, and computer storage medium for communication. A terminal device receives, in a low power (LP) mode and from a network device, an LP synchronization signal based on at least one of: an identity (ID) of a cell group of the network device, an ID of an LP-SS group of the network device, a tracking area ID associated with the network device, or a tracking area code associated with the network device; and detecting a wake-up signal from the network device based on the LP synchronization signal. As such, the terminal device can achieve and maintain the time synchronization with the network device in a certain precision, thus may utilize the synchronization to simplify the detection of wake-up signals, and enhance the detection performance.