Group Communication Continuity via Multicast to Unicast Switching
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Solution Overview
Problem
In group communication services for LTE systems, switching from multicast to unicast transmission in the MBSFN domain often results in service interruptions due to the lack of an appropriate unicast EPS bearer, compromising service continuity.
Innovation Solution
A method where the GCSE-AS notifies terminals of the impending switch from multicast to unicast transmission, allowing them to set up a unicast bearer, ensuring seamless continuity by transmitting the group communication service over this newly established bearer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the network switches the service from multicast transmission to unicast transmission in the MBSFN domain, then network resources are made more efficient, but service continuity is compromised due to lack of appropriate unicast EPS bearer
Solution Approach 1:
The network side performs preliminary actions by notifying the terminal in advance about the upcoming transmission mode switch from multicast to unicast. This allows the terminal to proactively establish the necessary unicast EPS bearer before the actual switch occurs, ensuring service continuity while enabling efficient unicast transmission.
2Adaptability or versatility
If the network switches from multicast to unicast transmission without advance notification, then transmission mode flexibility is improved, but service interruption time increases
Solution Approach 1:
The network side sends a first notification message to the terminal in advance, indicating the planned switch from multicast to unicast transmission. The terminal uses this advance notice to establish the unicast EPS bearer before the switch, thereby minimizing service interruption time while maintaining transmission mode flexibility.
Solution Approach 2:
The terminal responds to the network's notification by establishing the unicast bearer and sending a second notification message back to confirm readiness. This feedback mechanism ensures coordinated switching with minimal interruption, balancing flexibility and time loss.
Data Source
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AI summary
Disclosed are a method, device and system for maintaining the continuity of a group communication service, for solving the problem in the prior art that the service continuity requirement of group communication may not be satisfied due to the switching of network service from multicast transmission to unicast transmission in an MBSFN domain. The method comprises: when determining that group communication service needs to be switched from multicast transmission to unicast transmission, a GCSE-AS notifies a terminal served by the GCSE-AS that the GCSE-AS is going to switch the group communication service from multicast transmission to unicast transmission; and after receiving a first notification message transmitted by the terminal, the GCSE-AS transmits the group communication service over a unicast carrier established by the terminal for unicast transmission, and stops transmitting the communication service in multicast mode. The terminal has already established a unicast carrier for unicast transmission before the GCSE-AS switches the group communication service from multicast transmission to unicast transmission, thus ensuring the continuity of the group communication service.