Conditional Handover for XR Traffic and Cell Load Selection
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Solution Overview
Problem
Existing wireless communication systems face challenges in ensuring robustness and accuracy of signal transmission and reception, particularly in conditional handover (CHO) scenarios, especially for extended reality (XR) applications, due to factors like cell loading, cell coverage, and handover latency, which are not adequately addressed by current RRC measurement-based CHO execution conditions.
Innovation Solution
Implementing systems and methods that provide XR traffic characteristics and load information to base stations, allowing for informed handover decisions by UEs, including cell loading awareness and enhanced admission control, to select target cells based on both RRC measurements and congestion levels, thereby optimizing CHO execution conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RRC measurement-based CHO execution conditions are used, then handover decisions can be made based on signal quality, but cell loading and congestion levels are not considered leading to suboptimal target cell selection
Solution Approach 1:
The patent combines RRC measurements (signal quality) with load information (congestion levels) into a unified handover decision framework. The network entity transmits both measurement results and load information to the UE, which then executes CHO based on both parameters, merging two previously separate decision criteria into one comprehensive evaluation.
Solution Approach 2:
The network entity performs preliminary actions by transmitting load information from target cells to the serving cell before the handover execution. This allows the UE to have advance knowledge of target cell congestion levels, enabling informed CHO decisions before actually connecting to the target cell.
2Productivity
If traditional handover methods are used, then handover can be executed based on basic signal conditions, but handover latency remains high and XR service quality is degraded
Solution Approach 1:
The system performs preliminary actions by pre-configuring CHO conditions and transmitting load information before handover execution. The UE is provided with multiple candidate target cells and their respective load conditions in advance, allowing it to quickly select an appropriate target when CHO conditions are met, thereby reducing handover latency.
Solution Approach 2:
The handover decision framework becomes dynamic by continuously updating load information from target cells. Instead of static handover parameters, the system dynamically adjusts CHO execution decisions based on real-time or near-real-time load conditions, enabling faster and more adaptive handover execution.
3Ease of operation
If CHO is executed without load information, then handover decisions are simpler, but resource allocation efficiency deteriorates and congested cells may be selected
Solution Approach 1:
The patent segments the handover decision process into distinct components: measurement evaluation, load information assessment, and final CHO execution. The network entity handles the complex task of gathering and transmitting load information, while the UE focuses on evaluating conditions and executing handover, dividing the complexity between network and device.
4Speed
If admission control is not performed based on XR traffic characteristics, then handover processing is faster, but service quality for XR applications deteriorates
Solution Approach 1:
The system changes the parameters considered in admission control by specifically incorporating XR traffic characteristics (such as latency requirements, bandwidth needs) into the evaluation. This allows admission control to be tailored to XR services, ensuring that handovers maintain the specific quality requirements of XR applications while still processing efficiently.
Data Source
AI summary
Apparatuses, systems, and methods for conditional handover (CHO) and extended reality (XR) capacity enhancements. A base station may receive XR traffic characteristics from a user equipment (UE) and/or from a core network. The XR traffic characteristics may be UE specific and/or flow specific. The base station may provide, to one or more target base stations, the XR traffic characteristics as part of a conditional handover request. The XR traffic characteristics may be provided in an information element over an Xn interface. In addition, the base station may receive, from the one or more target base stations, handover request acknowledgments. The handover request acknowledgments may be based, at least in part, on admission control procedures performed based on the XR traffic characteristics. Further, the base station may generate a list of candidate target base stations based on the handover request acknowledgments and provide the list of candidate target base stations to the UE.