Wireless Time Reference Scheduling for Low-Power Synchronization
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Solution Overview
Problem
Wireless communication devices and network access nodes face challenges in maintaining a common time reference during low power modes due to oscillator drift and temperature variation, which become more prominent with extended periods of inactivity.
Innovation Solution
A method for wireless communication devices and network access nodes to negotiate and agree on desired and actual timings of timing signals, allowing devices to switch to a low power mode while maintaining an accurate time reference through periodic signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the wireless communication device enters low power mode to reduce power consumption, then power consumption is reduced, but time reference accuracy deteriorates due to oscillator drift and temperature variation
Solution Approach 1:
The device performs preliminary actions by determining desired timings of timing signals before entering low power mode. The device calculates and stores the expected timing information in advance, allowing it to maintain time reference accuracy without continuous network communication during the low power state.
Solution Approach 2:
The device uses feedback mechanisms by receiving timing signals from the network access node at predetermined intervals and comparing actual timings with desired timings. This feedback loop enables the device to adjust and maintain accurate time reference despite being in low power mode, resolving the contradiction between power saving and time accuracy.
2Measurement precision
If the device remains in operational mode to maintain time reference accuracy, then time reference accuracy is maintained, but power consumption increases
Solution Approach 1:
Instead of continuous operation, the device employs periodic action by receiving timing signals at predetermined intervals rather than continuously. This periodic reception maintains time reference accuracy while allowing the device to enter low power mode between intervals, thus reducing overall power consumption while preserving synchronization.
3Measurement precision
If timing signals are transmitted more frequently to maintain synchronization, then time reference accuracy is improved, but network resource consumption increases
Solution Approach 1:
The device applies partial action by receiving timing signals at predetermined intervals rather than continuously or at maximum frequency. This partial reception is sufficient to maintain time reference accuracy given the device's ability to compensate for drift and temperature variations, thereby avoiding excessive network resource consumption while achieving the required synchronization level.
Data Source
AI summary
A method is disclosed—for a wireless communication device served by a network access node—of keeping a time reference at the wireless communication device. The wireless communication device is configured for operation according to at least first and second operational modes, the second operational mode having lower power consumption than the first operational mode. The method comprises (during operation according to the first operational mode) determining (for the second operational mode) desired timings of timing signals to be transmitted from the network access node, and transmitting a request signal to the network access node, wherein the request signal carries information of the desired timings of timing signals to be transmitted from the network access node. In some embodiments, the method further comprises receiving a response signal from the network access node, wherein the response signal carries information of actual timings of timing signals to be transmitted from the network access node. Corresponding method for a network access node, apparatuses, wireless communication device, network access node and computer program product are also disclosed.