Power Headroom Reporting Granularity for 5G Uplink Scheduling
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Solution Overview
Problem
The existing power headroom reporting methods in LTE systems are inadequate for 5G new radio (NR) systems, as they report power headroom on a per cell basis, which fails to provide the necessary granularity for accurate uplink scheduling, especially with supplementary uplink (SUL) and bandwidth part (BWP) operations.
Innovation Solution
The proposed solution involves reporting power headroom for each uplink subcarrier and/or bandwidth part, allowing for more precise power headroom reporting, which includes triggering conditions based on the activation or reconfiguration of these components, and a new PHR MAC CE format to support reporting of multiple subcarriers and bandwidth parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If power headroom is reported on a per cell basis as in LTE, then the reporting structure is simple and compatible with existing systems, but it cannot meet the requirements of 5G NR systems that need finer granularity for accurate uplink scheduling
Solution Approach 1:
The patent divides the power headroom reporting into multiple granularity levels: cell-level, carrier-level, and bandwidth part-level reports. Each level provides power headroom information for different scopes, enabling the base station to obtain precise power status for specific bandwidth parts while maintaining a hierarchical structure that manages complexity through organized segmentation of reporting domains.
2Measurement precision
If power headroom reporting includes multiple uplink subcarriers and bandwidth parts, then scheduling accuracy improves, but the size and complexity of the PHR MAC CE increases
Solution Approach 1:
The PHR MAC CE is segmented into multiple independent report structures, each corresponding to a specific bandwidth part. Each report contains power headroom information for a specific scope (cell, carrier, or bandwidth part), allowing the base station to receive detailed information without requiring a single overly complex message structure.
Solution Approach 2:
The patent introduces a hierarchical dimension to power headroom reporting by organizing reports at different levels (cell-level, carrier-level, bandwidth part-level). This multi-dimensional approach allows comprehensive power information to be conveyed through structured layers rather than a flat, monolithic message, managing information quantity through dimensional organization.
3Ease of operation
If power headroom reporting is triggered only by cell activation or reconfiguration, then the triggering conditions are simple to manage, but it cannot respond timely to activation or reconfiguration of uplink subcarriers or bandwidth parts
Solution Approach 1:
The triggering conditions are segmented into multiple independent events: cell activation/reconfiguration, carrier activation/reconfiguration, and bandwidth part activation/reconfiguration. Each segment triggers the appropriate level of power headroom reporting, enabling timely responses to specific events while maintaining manageable triggering logic through organized separation of trigger types.
Data Source
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AI summary
This application provides an uplink data transmission method, a terminal device and a base station. The transmission method includes: receiving, by a terminal device, an uplink grant from a base station; and sending, by the terminal device, a report to the base station, where the report includes a power headroom of each of at least one uplink subcarrier, and/or a power headroom of each of at least one bandwidth part. According to the uplink data transmission method, the terminal device, and the base station in embodiments of this application, a power headroom can be reported at a finer granularity. This helps improve accuracy of scheduling by the base station.