Two-Stage Wake-Up Receiver for LTE Power Saving
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Solution Overview
Problem
In LTE communication systems, the continuous monitoring of the Physical Downlink Control Channel (PDCCH) by user equipment (UE) leads to significant battery power consumption, especially during the Wake Up (WU) process for transitioning into Connected Discontinuous Reception (C-DRX) mode, which is wasteful when no data is scheduled for transmission, and results in reduced battery life and poor scheduling decisions due to stale channel state information.
Innovation Solution
Implementing a multi-stage Wake Up-Discontinuous Reception (WU-DRX) process that determines whether a WU process is warranted before performing it, using a Pre-Wake Up (PWU) stage for control signal monitoring in a low power mode or with a wake-up receiver, and only proceeding to the Wake Up stage if data is expected, thereby conserving power and reducing unnecessary WU processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs continuous PDCCH monitoring during C-DRX mode to ensure data reception readiness, then the reliability of data communication is improved, but the power consumption increases significantly
Solution Approach 1:
The patent segments the wake-up process into two distinct stages: a first wake-up stage for basic readiness and a second wake-up stage for full communication capability. This segmentation allows the UE to perform only essential operations initially, reducing power consumption while maintaining the ability to reliably receive data when needed.
Solution Approach 2:
The patent implements preliminary actions by performing basic wake-up operations (first wake-up stage) before full data reception preparation (second wake-up stage). This preliminary action includes essential tasks like monitoring wake-up indicators and performing basic synchronization, allowing the UE to be partially ready without consuming full power for all possible operations.
2Speed
If the UE performs wake-up process according to predetermined schedule to ensure readiness for data transmission, then the responsiveness to data transmission is improved, but the power consumption increases due to unnecessary wake-up operations
Solution Approach 1:
The patent introduces dynamic wake-up indication where the network can dynamically signal whether data transmission is actually scheduled. The UE transitions from static scheduled wake-up to dynamic wake-up based on network indication, allowing the system to adapt wake-up behavior to actual traffic conditions and reduce unnecessary wake-up operations.
Solution Approach 2:
The patent implements feedback mechanisms where the network provides wake-up indicators to the UE based on actual data scheduling decisions. This feedback loop allows the UE to adjust its wake-up behavior according to real network conditions, ensuring responsiveness only when data is actually scheduled, thereby avoiding unnecessary power consumption.
3Reliability
If the UE performs full wake-up process including RF and baseband warm-up to ensure communication readiness, then the communication quality is improved, but the time required for wake-up increases
Solution Approach 1:
The patent segments the wake-up process into distinct stages with different levels of preparation. The first wake-up stage performs essential operations quickly, while the second wake-up stage performs more comprehensive preparation only when needed. This segmentation reduces the time for initial wake-up while maintaining communication quality when full preparation is performed.
Solution Approach 2:
The patent performs preliminary wake-up actions (first wake-up stage) that prepare essential components without completing full warm-up procedures. This preliminary action includes basic synchronization and monitoring setup, allowing the UE to be quickly ready for potential data transmission while maintaining the option to perform full warm-up if data is actually scheduled.
Data Source
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AI summary
Systems and method of embodiments herein operate to conserve battery power of user equipment (UE). Embodiments determine whether waking up a UE receiver would be beneficial and based on the determination, the UE either wakes up the receiver or returns to sleep. Embodiments determine whether to wake up the receiver by performing pre-wake up (PWU) operation which either wakes up the receiver in a low power mode or wakes up the UE's wake up receiver. It may be determined whether a wake up (WU) signal is received during a PWU stage. If a WU signal is received during the PWU stage the UE may perform a full wake up of the receiver. If a WU signal is not received the UE may return to idle mode. In embodiments, WU (Wake Up) DRX cycles are supplemented with a Full DRX (Discontinuous Reception) cycle.