ProSe Handover Control via Core Network Entity
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Solution Overview
Problem
Existing handover processes for radio terminals performing inter-terminal direct communication often result in delayed handovers due to extra signaling requirements and lack of involvement from controlling entities like the ProSe function entity, leading to mismatches in configuration information during inter-base station handovers.
Innovation Solution
A method where radio terminals communicate with a controlling entity through a radio access network and core network to establish ProSe direct communication, allowing for proactive transmission of handover control information to ensure seamless handovers between cells without relying solely on the radio access network, thus enabling the ProSe function entity to manage changes in communication states and configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the source base station sends handover commands to radio terminals during inter-base station handover, then the handover process can be executed, but handover delays occur due to extra signaling requirements and lack of involvement from controlling entities
Solution Approach 1:
The target base station proactively sends handover control information to the controlling entity (ProSe function entity) before the actual handover occurs. This preliminary action allows the controlling entity to prepare configuration information in advance, reducing signaling requirements during the handover execution phase and minimizing handover delays.
2Device complexity
If the radio access network manages handover without core network involvement, then the handover process is simplified, but mismatches in configuration information occur during inter-base station handovers
Solution Approach 1:
The controlling entity (ProSe function entity) acts as an intermediary between the radio access network and the core network during handover. It receives handover control information from the target base station, manages configuration information, and ensures consistency across the handover process, thereby maintaining reliability without excessive complexity.
3Loss of energy
If the controlling entity is not involved in the handover process, then the signaling overhead is reduced, but the controlling entity cannot recognize changes in ProSe communication state
Solution Approach 1:
The target base station sends handover control information to the controlling entity before handover execution. This preliminary notification enables the controlling entity to recognize and prepare for changes in ProSe communication state without requiring extensive signaling during the actual handover, thus balancing information completeness with signaling efficiency.
Data Source
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AI summary
A radio terminal (1) communicates with a controlling entity (9) through a first cell (32S) managed by a first radio access network entity (31S) located in a radio access network (RAN) (3) and also through a core network connected to the RAN (3) in order to establish ProSe communication with a second radio terminal (2), and then starts the ProSe communication (103) with the second radio terminal (2) in the first cell (32S). The radio terminal (1) transmits or receives, to or from the controlling entity (9), first control information about a handover of the first and second radio terminals (1, 2) from the first cell (32S) to a second cell (32T) managed by a second radio access network entity (31T) located in the RAN (3). This contributes to improvement in an inter-base station handover of a radio terminal that is performing inter-terminal direct communication.