Power Headroom Reporting for Carrier Aggregation
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Solution Overview
Problem
In mobile communication systems supporting carrier aggregation, there is a need for an efficient method to report Power Headroom (PH) for User Equipment (UE) as the existing uplink transmission power determination algorithms are designed for single carrier scenarios, making it difficult to manage power effectively with multiple carriers.
Innovation Solution
A method and apparatus for efficiently reporting Power Headroom (PH) in a mobile communication system supporting carrier aggregation, where the UE determines and transmits PH values for multiple activated serving cells based on real transmission or reference formats, using indicators to differentiate between the two, and transmits an extended PH report on one of the carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing uplink transmission power determination algorithm is used for single carrier scenarios, then the power management is simple, but it becomes difficult to manage power effectively when multiple carriers are used in carrier aggregation
Solution Approach 1:
The patent segments the power headroom reporting by introducing separate indicators for each serving cell. Each PH report includes a first indicator for a first serving cell and a second indicator for a second serving cell, allowing independent tracking and management of power headroom for each carrier in the carrier aggregation scenario.
Solution Approach 2:
The patent adds a new dimension to power headroom reporting by introducing cell-specific indicators that differentiate between multiple serving cells. This transforms the single-dimension power reporting (single carrier) into a multi-dimensional reporting structure that can handle multiple carriers simultaneously.
2Measurement precision
If per-carrier Power Headroom reporting is implemented for multiple carriers, then accurate power management is achieved, but signaling overhead increases
Solution Approach 1:
The patent merges multiple power headroom reports into a single uplink transmission. By combining the first PH report for the first serving cell and the second PH report for the second serving cell into one unified report structure, the patent reduces the number of separate transmissions needed while still providing per-carrier accuracy.
Solution Approach 2:
The patent creates a universal PH report structure that can accommodate multiple serving cells simultaneously. The report format is designed to be multi-functional, handling both single-carrier and multi-carrier scenarios through the inclusion of cell-specific indicators, thereby reducing the need for separate reporting mechanisms.
3Loss of information
If an extended PH report with multiple indicators is transmitted, then complete power information is provided, but the report size and processing complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-defining the indicator structure and encoding rules for multiple serving cells. The first and second indicators are predetermined to represent specific serving cells, allowing the base station to efficiently decode and process the power headroom information without complex real-time analysis.
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 determining 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 determined 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. The each indicator is set to “0”, if the corresponding PH is determined based on the real transmission, and the each indicator is set to “1”, if the corresponding PH is determined based on the reference format.