Voice Service Redirection With GBR Bearer Retention in LTE
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Solution Overview
Problem
In LTE networks, voice service interruptions and high call drop rates occur due to the release of GBR bearers during redirection processes, particularly in scenarios where the current serving cell is unsuitable for maintaining voice quality, leading to poor user experience.
Innovation Solution
A RAN device actively redirects the voice service terminal, releases the RRC connection, and instructs the CN device to retain the GBR bearer, ensuring it is not released during redirection, allowing the CN device to restore the voice service using the retained GBR bearer upon re-access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the RRC connection is released during redirection process, then the terminal can be redirected to a new cell, but the GBR bearer is released causing voice service interruption
Solution Approach 1:
The patent segments the bearer management from the connection management. The RRC connection is released for redirection while the GBR bearer is preserved separately in the core network. This allows the connection to be torn down (enabling redirection) while the service bearer remains intact (maintaining voice service continuity).
Solution Approach 2:
The patent extracts the GBR bearer retention requirement from the standard connection release process. By instructing the core network to retain the GBR bearer independently of the RRC connection release, the voice service bearer is separated from the control plane connection that is being released for redirection purposes.
2Reliability
If the GBR bearer is retained during redirection, then voice service continuity is maintained, but the core network must be instructed to retain the bearer
Solution Approach 1:
The patent applies preliminary action by including the bearer retention instruction in the RRC connection release message before the actual connection release occurs. The core network is pre-instructed to retain the GBR bearer, so when the connection is released and the terminal redirects, the bearer is already preserved and ready for quick restoration.
Solution Approach 2:
The RRC connection release message acts as an intermediary carrier that conveys the bearer retention instruction from the network to the core network. This single message performs dual functions: initiating the connection release for redirection and simultaneously instructing the core network to preserve the GBR bearer.
3Reliability
If all GBR bearers are retained, then voice service restoration is simplified, but other service bearers cannot be released
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different bearers. Instead of uniformly retaining or releasing all GBR bearers, the solution selectively retains only the voice service GBR bearer while allowing other GBR bearers to be released. This targeted approach preserves voice service continuity while freeing up other network resources.
Solution Approach 2:
The patent changes the state parameter of the GBR bearer from a uniform release action to a selective retention action. By modifying the bearer management parameter to distinguish voice GBR bearers from other GBR bearers, the system can retain only the necessary voice bearer while releasing others, optimizing resource usage.
Data Source
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AI summary
Embodiments of this application provide a method and an apparatus for processing a terminal that is performing a voice service, and a communications system. In the method, a RAN device actively redirects a voice service terminal, releases an RRC connection of the terminal, and instructs a CN device to retain a GBR bearer of the voice service terminal in a release process. Because a bearer type of a VOIP service is a GBR bearer, a bearer of the VOIP service is not released. When the terminal accesses a network again, the CN device may directly use the GBR bearer to restore the voice service, so as to avoid voice service interruption caused by releasing the bearer of the VOIP service in a redirection process, reduce a call drop rate, and improve user experience.