LTE Voice Redirection Bearer Reservation
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Solution Overview
Problem
In LTE networks, voice services experience call drops after user equipment (UE) is redirected due to poor link quality, as existing redirection methods fail to reserve the necessary bearers, leading to service disruptions.
Innovation Solution
The method involves a base station determining the need for redirection and instructing the core network and UE to reserve a guaranteed bit rate (GBR) or voice service bearer, ensuring that the bearer is reserved on both the core network and UE sides before the redirection, allowing for seamless voice service continuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redirection operation is performed on UE due to poor link quality, then link quality is improved, but voice service continuity deteriorates (call drop occurs)
Solution Approach 1:
The patent applies preliminary action by reserving the voice service bearer before the redirection operation. The base station sends a UE context release request message to the mobility management network element with voice redirection cause indication information, which triggers the core network to reserve the GBR bearer in advance. This ensures that when UE is redirected, the bearer is already reserved and ready, preventing call drop and maintaining voice service continuity.
2Ease of operation
If bearer is not reserved during redirection, then redirection operation is simple, but voice service quality deteriorates (call drop occurs)
Solution Approach 1:
The patent performs the bearer reservation action in advance by including voice redirection cause indication information in the UE context release request message. This triggers the mobility management network element to reserve the GBR bearer before UE actually performs redirection. The approach maintains operational simplicity while ensuring voice service quality through pre-reservation.
Solution Approach 2:
The patent introduces the mobility management network element as an intermediary between the base station and the core network. This intermediary receives the UE context release request message with voice redirection cause indication information and coordinates the bearer reservation process, simplifying the overall redirection operation while ensuring reliable voice service continuation.
3Reliability
If GBR bearer is reserved in core network and UE, then voice service continuity is maintained, but system complexity increases
Solution Approach 1:
The patent applies universality by using the existing UE context release request message and RRC connection release message for dual purposes: normal UE context release and voice service bearer reservation. The voice redirection cause indication information is embedded in these existing messages, allowing the same message structure to serve multiple functions without adding significant system complexity.
Solution Approach 2:
The mobility management network element acts as an intermediary that coordinates the bearer reservation between core network and UE. It receives the UE context release request with voice redirection cause indication, reserves the bearer locally, and sends suspend bearer messages to the gateway device, thereby managing the complexity centrally rather than distributing it across multiple components.
Data Source
AI summary
This application relates to the field of communications technologies, and discloses example redirection methods and apparatuses to ensure that a call drop does not occur after UE is redirected. One example method includes determining, by a base station, that a redirection operation needs to be performed on user equipment UE, and then instructing a core network to reserve a guaranteed bit rate (GBR) bearer or a voice service bearer that is corresponding to the UE. The UE is then instructed to reserve the GBR bearer or the voice service bearer that is corresponding to the UE. After the UE is redirected to a new base station, the voice service bearer of the UE is reserved on a UE side.