Power Headroom Reporting Across Source and Target Cells
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Solution Overview
Problem
Conventional 5G systems are designed to perform power headroom reporting (PHR) for only one primary cell during a handover procedure, failing to accommodate the dual activity protocol structure (DAPS) that maintains two connection paths, leading to inefficiencies in PHR procedures during handovers.
Innovation Solution
The method involves determining conditions for PHR triggering, selecting appropriate PHR formats, and reporting PHR information for both source and target cells during a DAPS handover, using multiple entry MAC CEs with virtual serving cell identifiers and different logical channel identifiers to differentiate between cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional PHR procedure is used during handover, then the system maintains simplicity in PHR reporting, but it fails to accommodate dual activity protocol structure requiring reporting for both source and target cells
Solution Approach 1:
The PHR reporting mechanism is segmented into separate reporting procedures for source cell and target cell. The UE performs independent PHR calculations and reporting for each cell, with source cell PHR reported on uplink resources of source cell and target cell PHR reported on uplink resources of target cell. This segmentation allows the system to accommodate DAPS handover while maintaining clear, manageable reporting procedures for each cell independently.
Solution Approach 2:
The patent introduces a new dimension to PHR reporting by enabling simultaneous reporting for multiple cells (source and target) during handover. Instead of a single PHR report for one cell, the system now operates in a multi-dimensional space where PHR information is reported across multiple cells and multiple uplink resources simultaneously, thus adapting to DAPS handover requirements.
2Loss of information
If PHR is reported for both source and target cells during DAPS handover, then the system achieves complete power headroom information, but it increases signaling overhead and processing complexity
Solution Approach 1:
The patent extracts PHR reporting for source cell and target cell into separate, independent reporting procedures. Each PHR report contains only the necessary information for its respective cell, extracting and reporting only the relevant power headroom data without redundant information. This reduces signaling overhead while maintaining complete power headroom information for both cells.
Solution Approach 2:
The UE performs preliminary PHR calculations and preparations for both source and target cells before actual reporting. The system pre-computes power headroom values and prepares reporting structures in advance, reducing real-time processing complexity during the handover execution phase while ensuring complete information is available for reporting.
3Reliability
If separate PHR reporting for source and target cells is implemented, then the system maintains data buffer preservation, but it requires additional uplink resources and increases resource allocation complexity
Solution Approach 1:
The patent applies local quality by allocating uplink resources specifically tailored to each cell's PHR reporting needs. Source cell PHR is reported using uplink resources of the source cell, while target cell PHR is reported using uplink resources of the target cell. Each resource allocation is optimized locally for its specific purpose, maintaining data buffer preservation while managing resource allocation complexity through localized, purpose-specific resource assignment.
Data Source
AI summary
A system and method for power headroom reporting (PHR) during a Dual Activity Protocol Structure (DAPS) handover procedure. The system and method include receiving, by a wireless communication device, a handover command to begin a dual activity protocol structure (DAPS) handover; detecting, by the wireless communication device during the DAPS handover, a condition for power headroom reporting (PHR); and performing, by the wireless communication device during the DAPS handover, the PHR.