Radio Base Station CSFB Handover Redirection Logic
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Solution Overview
Problem
In mobile communication systems, users cannot access voice services in systems where these services are not provided, leading to issues with handovers between different systems like LTE and 3G, as radio resources may be fully allocated, preventing the establishment of a radio access bearer and subsequent service provision.
Innovation Solution
A radio base station determines the handover capability of a mobile station and selects between CSFB procedures by handover or redirection to ensure service provision, switching to redirection if radio resources cannot be secured for handover, thereby avoiding call loss and improving CSFB success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover procedure is used to provide service in second system, then service availability is improved, but radio resource allocation becomes insufficient when resources are fully allocated
Solution Approach 1:
The patent implements dynamic selection between handover and redirection procedures based on real-time radio resource availability. The base station monitors resource status and adaptively chooses the appropriate CSFB procedure, transitioning from a static handover approach to a dynamic resource-aware decision-making system that optimizes service delivery under varying resource conditions.
Solution Approach 2:
The patent changes the operational parameter of the handover procedure by introducing a conditional switch between handover and redirection modes. When radio resources are insufficient, the system parameter changes from attempting handover to executing redirection, thereby maintaining service availability while adapting to resource constraints.
2Adaptability or versatility
If radio access bearer establishment is required for handover, then handover capability is improved, but connection establishment fails when radio resources are fully allocated
Solution Approach 1:
The patent prepares alternative procedures (redirection) in advance as a cushioning mechanism against potential handover failures. By having redirection ready as a backup option, the system cushions against the risk of connection establishment failure due to resource constraints, ensuring continuous service availability even when handover cannot be completed.
Solution Approach 2:
The patent introduces redirection as an intermediary procedure between the LTE system and the second system when direct handover is not feasible. This intermediary approach allows the mobile station to access services in the second system through an alternative path, maintaining connectivity when the primary handover path is blocked by resource limitations.
3Quantity of substance
If mobile station is redirected to second system without handover, then resource allocation pressure is reduced, but service provision speed may be affected
Solution Approach 1:
The patent makes the service provision process dynamic by selecting between handover and redirection based on resource conditions. When resources are abundant, fast handover is used; when resources are constrained, redirection is employed. This dynamic adaptation optimizes the balance between resource conservation and service delivery speed.
Solution Approach 2:
The patent applies partial action by using redirection only when necessary (when handover fails or resources are insufficient), rather than always using redirection. This selective approach ensures that the simpler but potentially slower redirection method is used only to the extent needed to maintain service availability, minimizing time loss while conserving resources.
Data Source
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AI summary
A radio base station in a first mobile communication system is disclosed. The radio base station includes a radio communication unit; a network communication unit; and a determining unit. If a massage received by the network communication unit from a switching station indicates that a mobile station is requesting a service which is not provided in the first mobile communication system but which is provided in a second mobile communication system and it is determined by the determining unit that a handover to the second mobile communication system cannot be conducted, the network communication unit requests the switching station to release a connection with the mobile station. Then the radio communication unit reports to the mobile station that the connection should be released in accordance with an instruction from the switching station.