Power Headroom Reporting MAC CE Structure for Supplemental Uplink Carriers
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Solution Overview
Problem
In Multi-Radio Access Technology (RAT)-Dual Connectivity (MR-DC) and MR-Multiple Connectivity (MR-MC) scenarios, existing technologies face challenges in efficiently reporting power headroom across different radio access technologies, particularly in LTE-NR scenarios, where the existing Power Headroom Report (PHR) structure is not adequately designed to handle supplemental uplink carriers, leading to difficulties in resource management and uplink bandwidth allocation.
Innovation Solution
The proposed solution involves modifying the PHR MAC Control Element structure to include additional octets for indicating the presence of power headroom for each serving cell, with specific configurations for Dual Connectivity and Multiple Entry scenarios, allowing for the reporting of power headroom for both original and supplemental uplink carriers, and using reserved bits to differentiate between them, enabling more accurate power headroom reporting and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing PHR MAC CE structure is used, then the structure remains simple and compatible with legacy systems, but it cannot adequately report power headroom for supplemental uplink carriers in MR-DC scenarios
Solution Approach 1:
The PHR MAC CE structure is segmented into multiple parts: a first octet with a first bitmap for original uplink carriers, and a second octet with a second bitmap for supplemental uplink carriers. This segmentation allows independent tracking and reporting of power headroom for different uplink carrier types, enabling the system to accommodate supplemental uplink carriers without completely redesigning the existing structure.
Solution Approach 2:
The solution adds a new dimension to the PHR reporting by introducing a second bitmap in the second octet specifically for supplemental uplink carriers, while retaining the first bitmap in the first octet for original uplink carriers. This dimensional expansion allows the system to report power headroom for multiple uplink carrier types simultaneously within a single PHR MAC CE, enhancing adaptability without excessive complexity.
2Measurement precision
If the PHR structure is modified to include additional octets for supplemental uplink carriers, then reporting accuracy improves, but resource overhead increases
Solution Approach 1:
The solution implements partial action by conditionally including the second octet with the second bitmap only when supplemental uplink carriers are configured and power headroom reporting for them is needed. When supplemental uplink carriers are not present, the PHR MAC CE maintains its original size with only the first octet, thus avoiding unnecessary resource overhead while preserving the capability for enhanced reporting when required.
3Productivity
If separate PHR reporting for original and supplemental uplink carriers is implemented, then resource allocation efficiency improves, but processing complexity increases
Solution Approach 1:
The solution merges the reporting of power headroom for both original uplink carriers (first bitmap in first octet) and supplemental uplink carriers (second bitmap in second octet) into a single PHR MAC CE structure. This unified approach allows the network to process both types of power headroom reports simultaneously, improving resource allocation efficiency for multi-carrier scenarios while keeping processing complexity manageable through a consolidated structure rather than separate reporting mechanisms.
Data Source
AI summary
A method by a base station for receiving power headroom reporting from a user equipment (UE) in a Multi-Radio Access Technology (RAT)-Dual Connectivity (MR-DC) scenario, the method includes receiving a DC Power Headroom Report (PHR) Medium Access Control (MAC) Control Element (CE) from the UE, the DC PHR MAC CE having a fixed number of octets with cell index fields for indicating whether a power headroom (PH) for a serving cell with a corresponding cell index is reported, wherein the fixed number of octets is independent of a highest secondary Cell Index (SCellIndex) for serving cells with configured uplinks.