Base Station Handover Messaging With Selective UE Capability Inclusion
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Solution Overview
Problem
The increased size of UE Radio Access Capability signaling in 3GPP networks leads to high network resource usage and processing delays during handover, particularly for unusual UE models, and there is no clear method to decide whether to include UE capabilities with the Capability ID, leading to potential handover delays and increased signaling load.
Innovation Solution
A base station decides whether to include UE radio access capabilities in the handover message based on criteria such as Capability ID commonality, QoS requirements, network slice, and interface load, minimizing overhead and avoiding additional latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE radio access capabilities are always included in handover messages, then handover reliability is improved, but signaling overhead increases and processing delays occur
Solution Approach 1:
The patent extracts only the necessary UE capabilities information from the full capability set by using Capability ID references. Instead of including complete capability descriptions, the system extracts minimal identifying information (Capability ID) that can be mapped to full capabilities at the target base station, thereby reducing signaling overhead while maintaining handover reliability.
Solution Approach 2:
The patent segments the capability information transmission into two parts: (1) Capability ID transmission in the handover message, and (2) full capability mapping at the target base station using stored mappings or on-demand retrieval. This segmentation allows the handover message to remain compact while ensuring complete capability information is available where needed.
2Quantity of substance
If UE capabilities are selectively excluded from handover messages to reduce overhead, then signaling overhead is reduced, but handover delays increase for unusual UE models
Solution Approach 1:
The patent applies preliminary action by pre-storing capability ID mappings at the target base station before handover occurs. The target base station maintains a cache of common capability mappings and can immediately resolve Capability IDs to full capabilities without waiting for additional signaling exchanges, thus avoiding handover delays while still reducing overhead.
Solution Approach 2:
The system implements feedback mechanisms where the source base station can indicate whether the UE model is common or unusual, and the target base station can request capability information from the core network if the Capability ID is not recognized. This feedback loop ensures that unusual UE models receive appropriate handling while common models benefit from fast processing.
3Speed
If base stations cache all capability ID mappings, then handover speed is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by making the capability mapping cache optional and selective rather than universal. Base stations can choose to cache only common capability mappings that are relevant to their deployment context, while relying on core network retrieval for unusual models. This localized approach reduces memory and processing requirements while maintaining fast handover for the majority of cases.
4Measurement precision
If complete UE capabilities are transmitted during handover, then capability accuracy is improved, but network resource usage increases
Solution Approach 1:
The patent uses copying by transmitting a reference (Capability ID) instead of the full capability description. The target base station retrieves the complete capability information from its cached mappings or from the core network, creating a local copy of the needed information. This approach maintains capability accuracy while dramatically reducing the amount of data transmitted over the network.
Data Source
AI summary
The disclosure provides a method performed by a base station. The method comprises, when the base station is acting as a source base station for handover of a wireless device to a target base station: preparing a handover message for transmission to the target base station, the handover message comprising an indication of an identity associated with a set of capabilities of the wireless device; and causing the handover message to be transmitted to the target base station. The step of preparing the handover message comprises selectively including the set of capabilities of the wireless device in the handover message based on one or more criteria.