Voice Call Fallback to Circuit Switched Domain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current voice call fallback mechanisms in LTE networks experience significant delays due to serial processing of CS handover and CS core network processing, affecting user experience.
Innovation Solution
Implementing a method that parallelizes CS handover and CS core network processing by directly instructing an eNB to initiate CSFB handover and using an Sv interface between the MME and MSC to send PS to CS Handover Request messages, allowing simultaneous execution of CS handover and CS core network procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If CS handover and CS core network processing are performed in serial manner, then processing reliability is maintained, but connection delay increases significantly
Solution Approach 1:
The patent initiates CS handover procedure in advance by sending Handover Request from eNB to MME before the CS core network processing is fully completed. This preliminary action allows the handover to start earlier, reducing overall connection delay while maintaining reliability through proper sequencing of subsequent steps.
Solution Approach 2:
The patent transforms the single-dimensional serial processing into a multi-dimensional parallel processing approach by executing CS handover and CS core network processing simultaneously through coordinated message exchanges between MME, eNB, and MSC, thereby reducing total processing time while maintaining system reliability.
2Productivity
If parallel processing of CS handover and CS core network procedures is implemented, then connection delay is reduced, but system complexity increases
Solution Approach 1:
The patent segments the parallel processing into distinct functional modules: eNB handles radio resource management and handover initiation, MME coordinates between PS and CS domains, and MSC manages CS call setup. This segmentation allows parallel execution while keeping each node's complexity manageable through clear interface definitions.
Solution Approach 2:
The MME acts as an intermediary coordinator between the eNB (PS domain) and MSC (CS domain), managing the parallel processing through standardized message exchanges. This intermediary role simplifies the overall system complexity by providing a centralized coordination point rather than requiring direct complex interactions between all components.
3Adaptability or versatility
If radio module tunes from LTE network to 2G/3G network for voice call, then voice service compatibility is achieved, but service interruption time increases
Solution Approach 1:
The patent performs the radio module tuning from LTE to 2G/3G network in advance as part of the handover procedure before the actual voice call setup begins. This preliminary frequency switching ensures that when the call is established, the radio is already tuned to the correct network, minimizing perceptible service interruption.
Solution Approach 2:
The patent maintains continuous useful action by overlapping the radio tuning process with the call setup signaling procedures. The handover command is sent while the radio module is already tuning, and data services continue to be managed by the PS domain during the transition, ensuring no complete service interruption occurs.
Data Source
AI summary
A method for voice call fallback to a circuit switched (CS) domain disclosed in the present invention includes: receiving a Service Request message from a calling user equipment (UE), where the Service Request message includes called number information of a voice call in a CS domain, instructing an evolved NodeB (eNB) to initiate circuit switched fallback (CSFB) handover; receiving a Handover Request message from the eNB, where the Handover Request message includes information required for CS handover, selecting a mobile switching center (MSC) and sending a packet switched (PS) to CS Handover Request message to the MSC, where the PS to CS Handover Request message carries information required for the CS handover and a called number so that the MSC calls a called UE. The corresponding apparatuses and systems are also disclosed. The technical solution of the present invention can reduce the connection delay.