SIP Call Re-Establishment After Duplicate INVITE Conflicts
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Solution Overview
Problem
Existing VoLTE call establishment methods fail to successfully connect two electronic devices due to asynchronous communication between the network and terminal, resulting in reduced success rates when multiple INVITE requests are sent, often leading to a 486 (user busy) error code and failed voice or video calls.
Innovation Solution
A call establishment method that interrupts the communication connection based on a first INVITE request and establishes a new connection using a second INVITE request by sending a target message, such as a CANCEL or BYE message, when duplicate INVITE requests are detected, ensuring successful call establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the MT device sends a 486 (user busy) error code for multiple INVITE requests, then call connection conflicts are avoided, but the call establishment success rate decreases
Solution Approach 1:
The patent applies preliminary action by having the MT device send a CANCEL message before processing the second INVITE request. This preliminary cancellation action clears the previous call state, preventing connection conflicts while allowing the new call to be established successfully. The CANCEL message is sent in advance to remove the harmful effect of the pending first INVITE request.
2Productivity
If the MT device processes multiple INVITE requests simultaneously, then call establishment speed is improved, but connection reliability deteriorates due to asynchronous communication failures
Solution Approach 1:
The patent applies dynamics by making the MT device's processing behavior adaptive rather than static. The device dynamically adjusts its handling of INVITE requests based on whether an ACK message has been received for the first request. If ACK is received, it processes normally; if not, it sends CANCEL before processing the second request. This dynamic adjustment maintains both speed and reliability.
3Stability of the object's composition
If the MT device maintains strict protocol compliance by sending 486 error codes, then protocol consistency is improved, but call establishment flexibility deteriorates in asynchronous communication scenarios
Solution Approach 1:
The patent applies parameter changes by modifying the response parameter sent by the MT device based on the communication state. Instead of always sending the fixed 486 error code, the device changes its behavior: it sends a CANCEL message first (changing the protocol flow parameter) when the first INVITE's ACK is not received, then processes the second INVITE normally. This parameter change allows the system to adapt to asynchronous communication failures while maintaining overall protocol consistency.
Data Source
AI summary
A call establishment method includes: in a case that a first INVITE request sent by a second electronic device is received and that an INVITE ACK message sent by the second electronic device is not received, receiving a second INVITE request; and in a case that it is determined that both the second INVITE request and the first INVITE request are sent by the second electronic device, sending a target message to the second electronic device, and establishing a communication connection based on the second INVITE request. The target message is used for interrupting a communication connection established on the basis of the first INVITE request.