Power Headroom Reporting Across Mixed-TTI 5G NR Carriers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication networks like 3GPP 5G NR, where carriers have different Orthogonal Frequency Division Multiplexing (OFDM) numerologies and/or different Transmission Time Intervals (TTIs), existing methods struggle to accurately report power headroom information due to misalignment of subframes/TTIs, leading to incorrect scheduling assumptions and resource underutilization.
Innovation Solution
The UE calculates power headroom information for a second serving cell with a shorter TTI length by identifying a third TTI that overlaps with a first TTI on a first serving cell and reports this information in an uplink transmission on the first serving cell, ensuring accurate power headroom reporting across carriers with different TTI lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If carriers are configured with different TTI lengths to support diverse service requirements, then system adaptability is improved, but power headroom reporting accuracy deteriorates due to subframe misalignment
Solution Approach 1:
The patent segments the power headroom reporting mechanism by introducing separate reporting structures for different TTI lengths. For carriers with different TTI lengths, the UE performs separate PHR calculations and reporting for each TTI length, preventing mixing of power headroom information from misaligned subframes and ensuring accurate reporting for each carrier type.
Solution Approach 2:
The patent adds a time dimension to the PHR reporting mechanism by introducing a time offset parameter that indicates the temporal relationship between PHR transmission subframes and the reference subframes for power headroom calculation. This allows the base station to correctly interpret power headroom values even when subframes are misaligned across carriers with different TTI lengths.
2Ease of operation
If PHR is reported for each activated serving cell with aligned subframes, then reporting simplicity is maintained, but resource utilization efficiency deteriorates when carriers have different TTI lengths due to inability to accurately reflect real-time power status
Solution Approach 1:
The patent introduces dynamic PHR reporting where the UE determines the appropriate PHR reporting mechanism based on the TTI length configuration of each serving cell. When carriers have different TTI lengths, the system dynamically switches to the enhanced reporting mechanism with time offset indicators, while maintaining the simpler aligned subframe reporting when TTI lengths are uniform, thus adapting complexity to actual needs.
Solution Approach 2:
The patent changes the reporting parameters by introducing a time offset indicator field in the PHR message when carriers have different TTI lengths. This parameter change allows the PHR to carry additional temporal context information, enabling the base station to accurately schedule uplink resources even when the PHR is transmitted in a subframe that is not aligned with the reference subframe of the reported carrier.
3Stability of the object's composition
If subframes are aligned across all carriers for PHR reporting, then reporting consistency is improved, but system flexibility deteriorates when supporting carriers with different OFDM numerologies and TTI lengths
Solution Approach 1:
The patent introduces a time offset indicator as an intermediary element between the PHR transmission subframe and the reference subframe for power headroom calculation. This intermediary parameter bridges the gap between misaligned subframes, allowing consistent and accurate PHR reporting even when carriers have different OFDM numerologies and TTI lengths, thus maintaining reporting consistency without requiring subframe alignment.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed. One apparatus is configured to determine that the UE is configured with a first subcarrier spacing (SCS) configuration for a first active bandwidth part (BWP) of a first serving cell, where the first SCS configuration is smaller than a second SCS configuration for a second active BWP of a second serving cell. The apparatus is further configured to transmit a power headroom report (PHR) in a slot associated with the first active BWP that overlaps with a plurality of slots associated with the second active BWP, where the PHR is for a first physical uplink shared channel (PUSCH) on a first slot of the plurality of slots associated with the second active BWP that fully overlaps with the slot associated with the first active BWP.