Power Headroom Reporting for Carrier Aggregation
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Solution Overview
Problem
In mobile communication systems supporting carrier aggregation, existing technologies face challenges in efficiently reporting Power Headroom (PH) for User Equipment (UE) due to the complexity of uplink transmission power determination across multiple carriers, leading to difficulties in optimizing resource allocation and maintaining interference mitigation.
Innovation Solution
A method and apparatus for efficiently reporting Power Headroom (PH) in a mobile communication system supporting carrier aggregation, where the UE calculates and transmits PH values for multiple activated serving cells based on real transmission or reference formats, using an extended PH report that includes indicators to differentiate between actual and reference calculations, allowing the base station to accurately determine PH values for each carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE uses multiple uplink and/or downlink carriers for carrier aggregation, then the data rate and capacity are improved, but the complexity of uplink transmission power determination increases
Solution Approach 1:
The patent segments the power headroom reporting by introducing per-carrier PH indicators (ph-Indicator) that separately identify the power headroom status for each uplink carrier. This segmentation allows the base station to independently determine transmission power for each carrier, resolving the complexity issue while maintaining the high data rate benefits of carrier aggregation.
2Ease of operation
If per-carrier Power Headroom reporting is implemented in carrier aggregation, then uplink transmission power management is improved, but signaling overhead increases
Solution Approach 1:
The patent uses a universal indicator field (ph-Indicator) that serves multiple functions: it identifies the serving cell, indicates the power headroom type (real or reference), and enables per-carrier power management. This multi-functionality achieves precise uplink power management while minimizing signaling overhead by avoiding separate indicator fields for each purpose.
3Ease of manufacture
If the existing uplink transmission power determination algorithm is applied to carrier aggregation, then implementation simplicity is maintained, but accurate power allocation across multiple carriers cannot be achieved
Solution Approach 1:
The patent introduces new parameters including per-carrier power headroom indicators (ph-Indicator) and extended power headroom reporting formats. These parameter changes enable the system to track and control transmission power for each carrier individually, achieving accurate power allocation while maintaining implementation feasibility through standardized protocol extensions.
Data Source
AI summary
A method and apparatus for transmitting a power headroom (PH) report by a terminal in a mobile communication system supporting carrier aggregation are provided. The method includes calculating respective PHs for multiple activated serving cells based on a real transmission or a reference format, setting respective indicators for the PHs, wherein each indicator indicates that a corresponding PH is calculated based on the real transmission or the reference format, and transmitting, to a base station, an extended PH report including the PHs and the indicators on one of the multiple activated serving cells.