Wireless Device Synchronization After Prolonged Sleep
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Solution Overview
Problem
Wireless devices, especially MTC devices, face challenges in efficiently re-acquiring synchronization with the network after prolonged sleep periods, as conventional methods are energy-intensive and prone to synchronization errors due to accumulated frequency drift, leading to potential missed paging opportunities.
Innovation Solution
A wireless device computes a time for synchronization based on estimated frequency drift and expected bursts, setting a timer to wake up and perform synchronization efficiently, reducing energy consumption by optimizing the synchronization process through intermediate sync procedures when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional synchronization methods are used after prolonged sleep periods, then synchronization is achieved, but energy consumption increases significantly
Solution Approach 1:
The wireless device performs preliminary frequency drift estimation before the synchronization procedure. By calculating the expected frequency offset based on sleep duration and oscillator characteristics in advance, the device can directly compensate for the drift during synchronization, avoiding the need for lengthy frequency search and correction procedures, thus reducing energy consumption while maintaining synchronization accuracy.
Solution Approach 2:
The synchronization procedure is made adaptive by dynamically adjusting the frequency offset compensation based on the actual sleep duration and observed frequency drift. The device modifies its synchronization approach according to the accumulated drift, using shorter and more efficient synchronization procedures when drift is predictable, thereby optimizing the balance between synchronization reliability and energy consumption.
2Use of energy by moving object
If prolonged sleep periods are used to save energy, then power consumption decreases, but synchronization errors accumulate
Solution Approach 1:
The device performs preliminary frequency drift estimation before the synchronization procedure. By calculating the expected frequency offset based on sleep duration and oscillator characteristics in advance, the device can directly compensate for the drift during synchronization, avoiding the need for lengthy frequency search and correction procedures, thus reducing energy consumption while maintaining synchronization accuracy.
Solution Approach 2:
The synchronization procedure incorporates feedback mechanisms where the device monitors the actual frequency offset during synchronization and adjusts its compensation strategy accordingly. This feedback loop allows the device to learn from actual drift patterns and optimize future synchronization procedures, maintaining accuracy even after prolonged sleep periods.
3Reliability
If frequent synchronization verification is performed to maintain accuracy, then synchronization reliability improves, but energy consumption increases
Solution Approach 1:
Instead of continuous synchronization verification, the device employs periodic synchronization checks at strategically determined intervals. By using the estimated frequency drift to predict when synchronization will be needed and performing synchronization only at those predicted moments, the device maintains synchronization accuracy while minimizing the energy consumption associated with frequent verification.
4Use of energy by moving object
If long DRX cycles are used for MTC devices, then power savings increase, but the risk of missing paging opportunities increases
Solution Approach 1:
The device performs preliminary frequency drift estimation and calculates the optimal synchronization timing before entering long DRX cycles. By proactively compensating for frequency drift and scheduling synchronization at precise moments when paging bursts are expected to occur, the device maintains reliable paging reception even during extended sleep periods, enabling longer DRX cycles without increasing the risk of missed pages.
Solution Approach 2:
The patent replaces the traditional mechanical approach of continuous monitoring and frequent synchronization with a predictive model based on frequency drift estimation. This substitution allows the device to operate in long DRX cycles with minimal active monitoring, achieving both power savings and reliable paging reception through intelligent prediction rather than continuous mechanical synchronization.
Data Source
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AI summary
A wireless device and method are described herein for implementing synchronization procedures when the wireless device operates using a prolonged sleep mode in a cellular network, wherein the synchronization procedures have a benefit of reducing the energy consumption of the wireless device's battery.