Secondary Cell Activation Timing Optimization
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Solution Overview
Problem
The existing methods for secondary cell activation and deactivation in carrier aggregation technologies face challenges due to variable activation timing, leading to potential delays and inefficiencies in power consumption and system performance, particularly in scenarios like blind activation and complex duplex configurations.
Innovation Solution
The method involves aligning the knowledge of secondary cell activation and deactivation between the eNB and UE by using power headroom reports (PHR) or estimated time periods to indicate when a secondary cell is ready for use, allowing for early activation and optimized deactivation timing, which can be triggered upon activation completion or prior to receiving an activation command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the eNB configures and immediately activates an SCell which has not been previously measured by the UE (blind activation), then the SCell activation can proceed without waiting for measurement completion, but the UE needs to perform primary synchronization signal (PSS)/secondary synchronization signal (SSS) timing acquisition which causes activation delays
Solution Approach 1:
The UE performs measurement and synchronization procedures in advance before the SCell activation command is received. When the eNB sends an activation command, the SCell is already synchronized and ready for immediate use, eliminating activation delay. This is achieved by the UE continuously monitoring and synchronizing with potential SCells before activation is requested.
2Reliability
If the SCell activation time is extended beyond 8ms to accommodate challenging cases (TDD configuration with mostly uplink subframes, MBSFN subframes, AGC algorithms), then activation reliability improves, but the likelihood of using activation/deactivation to control UE power consumption is reduced and unnecessary idle time occurs
Solution Approach 1:
The SCell activation timing is made dynamic and adaptable to different UE capabilities and network conditions. The eNB and UE exchange information about actual activation timing requirements, allowing the system to optimize the activation timer based on real-world performance rather than using a fixed conservative value. This enables faster deactivation timing adjustments for power saving when conditions permit.
3Ease of operation
If the eNB uses a fixed 8ms activation timer for SCell deactivation, then the deactivation timing is simple to manage, but it causes unnecessary idle time when the SCell is ready more quickly without knowledge of the network
Solution Approach 1:
The UE provides feedback to the eNB about its actual SCell activation timing through Power Headroom Reports (PHR) or other signaling mechanisms. This feedback allows the eNB to adjust the deactivation timer accurately, preventing premature deactivation and eliminating unnecessary idle time while maintaining simple timer management.
4Speed
If the UE performs comprehensive measurements and synchronization before SCell activation, then activation delays are avoided, but the UE power consumption increases due to continuous monitoring activities
Solution Approach 1:
The UE performs measurement and synchronization activities only when triggered by specific events or conditions, such as receiving a measurement configuration or being in a connected state with potential SCells of interest. This on-demand approach allows the UE to be ready for blind activation without continuous power-consuming monitoring of all possible SCells.
Data Source
AI summary
A method, apparatus and computer program product are provided in order to enhance network notification of secondary cell activation. In a first embodiment, the method includes receiving a secondary cell activation command, activating a secondary cell, and transmitting a PHR indicating activation of the secondary cell. In a second embodiment, the method includes receiving a secondary cell activation command, activating a secondary cell, and transmitting a signal indicating an expected time period until activation of the secondary cell. In a third embodiment, the method may optimize implicit SCell deactivation by receiving a secondary cell activation command, activating a secondary cell, receiving a PDCCH order for an uplink grant or a downlink assignment, and starting a secondary cell deactivation timer associated with the secondary cell in response to receiving the PDCCH order. A corresponding apparatus and computer program product are also provided.