Mobile Terminal Inter-System Handover via Bearer Capability
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Solution Overview
Problem
Current inter-system handover methods in communication networks are network-centric, lacking the ability for mobile terminals to initiate service-based handovers between different radio access technologies, which limits the utilization of suitable radio access technologies based on service requirements and quality.
Innovation Solution
A method allowing mobile terminals to initiate service-based inter-system handovers by setting specific Bearer Capability fields in call control messages, indicating the need for a different radio access technology, without requiring additional signaling, ensuring interoperability with terminals and network entities that lack support for this functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If network-centric handover methods are used, then network control over handover is maintained, but mobile terminals cannot initiate service-based handovers to optimize service quality
Solution Approach 1:
The mobile terminal performs preliminary actions by setting specific Bearer Capability fields in call control messages before the handover is executed. This allows the terminal to indicate its service requirements and trigger the handover process proactively, rather than waiting for network-initiated handover decisions.
Solution Approach 2:
The Bearer Capability fields serve as an intermediary mechanism between the mobile terminal and the network. By setting these fields to indicate unsupported radio access technologies, the terminal communicates its service requirements to the network without requiring direct handover control, allowing the network to autonomously make the handover decision.
2Adaptability or versatility
If additional signaling is added for terminal-initiated handover, then service-based handover capability is enabled, but signaling overhead increases
Solution Approach 1:
The Bearer Capability fields, which are already part of the standard call control message structure, are repurposed to carry handover initiation information. This multi-functional use of existing signaling elements enables terminal-initiated handover without adding separate dedicated signaling messages, thereby avoiding increased signaling overhead.
3Adaptability or versatility
If new handover initiation mechanism is implemented, then service quality optimization is improved, but interoperability with existing terminals and network entities is compromised
Solution Approach 1:
The solution uses existing Bearer Capability fields that are universally supported in call control messages. Legacy terminals and network entities that do not support the new handover initiation mechanism will simply ignore the handover indication in these fields, while newer entities can interpret and act upon them, ensuring backward compatibility.
Solution Approach 2:
The mechanism is designed to be self-service in that it automatically maintains interoperability without requiring additional configuration or coordination. Existing terminals continue to operate normally, while new terminals with the enhanced capability can autonomously initiate service-based handovers when needed.
Data Source
AI summary
The present invention provides a method of initiation a mobile originating service-based inter-system handover, and devices enabling the method. A communication network comprises at least two radio access networks (RANs) of different types, i.e. a radio access network (RAN) of a first type and a radio access network (RAN) of a second type. A dual-mode mobile terminal designed to be operable with both the RAN of the first type and the RAN of the second type communicates with the communication system via the RAN of the first type. The initiation of the inter-system handover is included in a transmission, which comprises at least one bearer capability (BC) field. The bearer capability (BC) field is set to indicate that a requested service is only operable with the RAN of the second type. In particular, at least one bearer capability (BC) field is set to a parameter value, which serves as indication for the receiving network and its processing entities, respectively, which receiving network indicated to carry out the inter-system handover initiated by the mobile terminal.