Reverse SRVCC Handover Preconfiguration for Voice Continuity
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Solution Overview
Problem
Existing reverse Single Radio Voice Call Continuity (SRVCC) technologies face challenges in ensuring good voice continuity and quality during handovers due to high interruption delays, particularly when transitioning from Circuit Switched (CS) to Packet Switched (PS) domains in 2G/3G and LTE networks.
Innovation Solution
A method involving preconfiguration of resource information in the Packet Switched domain by User Equipment (UE) before handover, establishing a forwarding channel between Access Transfer Gateway (ATGW) and Mobile Switching Center (MSC) using preallocated resources, allowing for seamless voice data transmission without relying on access transfer completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE enables the voice service to exit from the 2G/3G CS domain network first and then access the LTE network, then the access transfer processing is completed quickly, but the voice interruption delay exceeds 300 ms due to the lengthy access transfer procedure
Solution Approach 1:
The patent applies preliminary action by pre-configuring forwarding channel resources in the PS domain before the actual handover occurs. The network pre-allocates bearer resources and establishes forwarding channel parameters in advance, so that when handover is triggered, the UE can immediately use these pre-prepared resources without waiting for lengthy access transfer procedures, thus reducing voice interruption delay below 300 ms while maintaining fast access transfer
2Reliability
If the UE hands over the voice service bearer from CS domain to PS domain in the 2G/3G network first, then the service continuity is ensured, but the voice service quality remains low due to limitations of PS domain voice service in 2G/3G network
Solution Approach 1:
The patent introduces an intermediary forwarding channel that bridges the CS domain and PS domain during handover. The forwarding channel, established in the PS domain with pre-configured resources, acts as a mediator that allows high-quality PS domain voice service to be immediately available when the UE accesses LTE, while the CS domain connection can be gracefully terminated. This intermediary mechanism ensures both service continuity and high voice quality simultaneously
Data Source
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AI summary
The present invention provides a method, device, and system for processing reverse single radio voice call continuity. The method includes: before handing over a voice service from a CS domain network to a PS domain network, preconfiguring, in the PS domain network by a UE, information about resources needed for the voice service handover; and in the process of handing over, by the UE, the voice service from the CS domain network to the PS domain network, establishing a forwarding channel between a first network element of the PS domain and a second network element of the CS domain by using the preconfigured information about resources, where the forwarding channel is configured to forward voice service data between the UE and a peer UE after the UE accesses the PS domain network. A reverse SRVCC handover process in this embodiment is implemented without the need of waiting for completion of an access transfer procedure. This ensures good continuity performance of the voice service in the reverse SRVCC handover and also ensures that the voice service after the handover is capable of achieving good quality of the voice service.