MGCF Video RBT Interworking for CS to IMS Calls
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Solution Overview
Problem
Existing systems fail to enable the playing of multimedia Ring Back Tone (RBT) services across different domains, specifically preventing CS users from receiving video RBTs when calling IMS users, as they cannot query RBT service subscription status and cannot determine whether to play IMS video RBTs.
Innovation Solution
A method and device for implementing RBT interworking, where the Multimedia Ring Back Tone Application Server (MRBT AS) sends video RBT information to the Media Gateway Control Function (MGCF) to determine if a video RBT should be played, and notifies the home MSC to put through the calling terminal, allowing IMS video RBTs to be played to CS users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the prior art enables RBT function in PS domain and IMS domain, then the calling terminal in PS core network can receive signal tone from called party in CS domain, but the calling terminal in CS domain cannot receive MRBT from called party in PS core network
Solution Approach 1:
The MGCF acts as an intermediary between the CS domain (MSC) and IMS domain (MRBT AS). It receives video RBT information from the MRBT AS, determines whether to play video RBT, and notifies the home MSC to put through the calling terminal. This intermediary enables bidirectional RBT interworking between domains that previously could not communicate service subscription status.
2Reliability
If the home MSC server cannot query RBT service subscription status in different domain, then the system cannot determine whether to play IMS video RBT, but enabling cross-domain query increases system complexity
Solution Approach 1:
The system segments the RBT service functionality into domain-specific components: the MRBT AS in the IMS domain handles subscription status and video RBT information, while the MSC in the CS domain handles call control. The MGCF segments the interworking function by translating and transmitting only necessary information between domains, avoiding full system integration and reducing overall complexity.
3Ease of operation
If the system cannot determine whether calling party needs to be put through after receiving Alerting message, then video RBT cannot be played to CS user, but adding determination logic increases processing time
Solution Approach 1:
The system performs preliminary determination of whether to play video RBT and whether to put through the calling terminal before the call is fully established. The MGCF receives video RBT information from the MRBT AS, makes the determination early in the call setup process, and notifies the home MSC accordingly, enabling automated decision-making that reduces manual intervention and speeds up call setup.
Data Source
AI summary
A method for implementing Ring Back Tone (RBT) interworking, a Media Gateway Control Function (MGCF) device, and an Application Server (AS) are provided. A Multimedia Ring Back Tone (MRBT) service is triggered when a Circuit Switched (CS) user originates a call to an MRBT subscriber in an Internet Protocol Multimedia Subsystem (IMS). The method includes: receiving a message sent by an MRBT AS, where the message carries video RBT information; and notifying a Mobile Switching Center (MSC) to put through a calling terminal if determining that a video RBT needs to be played to the calling terminal according to the message. Therefore, a video RBT can be played when a CS user originates a call to an IMS user in the case of network interworking. An IMS video RBT may be played to the calling party when the CS user originates a call to the IMS user.