Call Signaling Recovery for Caller Ring Back Tone Audio Continuity
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Solution Overview
Problem
Terminals with caller ring back tone function experience higher instances of no audio or one-way audio during calls due to additional signaling procedures and potential signaling loss, affecting user experience.
Innovation Solution
Implementing a method where terminals and network devices handle signaling interactions by assuming receipt of missing ACK signals, sending alternate 200 OK responses, and setting timers to manage signaling wait times, ensuring subsequent interactions proceed and voice data transmission occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the caller ring back tone function is enabled on the terminal, then the user can listen to a ring tone during call waiting, but the terminal becomes more prone to no audio or one-way audio problems during calls
Solution Approach 1:
The terminal performs preliminary actions by sending the second 200 OK signaling in advance when the first ACK signaling is not received but the second INVITE signaling is received. This proactive response prevents the call setup from stalling and ensures audio connectivity is established, resolving the reliability issue while maintaining the caller ring back tone function
Solution Approach 2:
The terminal prepares for potential signaling loss by having a fallback mechanism ready. When the first ACK signaling is not received, the terminal assumes it was received and proceeds to send the second 200 OK signaling, cushioning against the harmful effect of signaling loss and preventing call setup failure
2Adaptability or versatility
If additional signaling procedures are added during call establishment for caller ring back tone, then the ring back tone can be played to the calling terminal, but the probability of signaling loss increases
Solution Approach 1:
The terminal uses feedback from receiving the second INVITE signaling to determine whether to send the second 200 OK signaling. This feedback mechanism allows the terminal to adapt its response based on the signaling it receives, ensuring call setup continues even when the first ACK signaling is lost
Solution Approach 2:
The second INVITE signaling acts as an intermediary indicator that helps the terminal infer the status of the first ACK signaling. By using this intermediate signal, the terminal can make informed decisions about whether to proceed with sending the second 200 OK signaling, reducing the impact of signaling loss
Data Source
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AI summary
A call connection method and apparatus are provided, and are applied to a process of establishing a call between a calling side and a called side in a scenario in which a called terminal subscribes to a caller ring back tone business. The method includes: In a process of signaling interaction between a calling terminal and the called terminal, after an action of tapping answering by a user of the called terminal, if the called terminal has not received first ACK signaling replied by a network side (for example, an S-CSCF), but receives second INVITE signaling, in this case, the called terminal assumes that the network side has sent the first ACK signaling, and replies to the network side with second 200 OK (INVITE) signaling after receiving the second INVITE signaling. In comparison with a manner of replying 491 signaling in this case, the method in embodiments of this application reduces a probability of no audio in a call, can increase a probability of successful calls, and helps improve user call experience.