I-SMF Capability Selection for Multicast Broadcast PDU Sessions
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Solution Overview
Problem
In scenarios where an intermediate session management function (I-SMF) does not support multicast broadcast service (MBS), data transmission occurs in unicast manner, leading to waste of network resources and low utilization of radio access network resources.
Innovation Solution
A method to select an intermediate session management function network element that supports MBS by learning its multicast/broadcast capability information, enabling data transmission to terminal devices in a multicast/broadcast manner, thereby optimizing network resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an intermediate session management function (I-SMF) is inserted into the control plane path of a PDU session, then the topology of session management function and user plane function (ETSUM) is enhanced, but the I-SMF may not support multicast broadcast service (MBS), causing data transmission to occur only in unicast manner and leading to waste of network resources
Solution Approach 1:
The patent applies preliminary action by having the AMF determine whether the I-SMF supports MBS before establishing the PDU session. The capability information is obtained in advance through network repository function (NRF) query or direct indication from I-SMF, allowing the system to proactively select an appropriate I-SMF that supports MBS, thereby preventing the need for later mode switching and avoiding network resource waste
Solution Approach 2:
The patent uses the AMF as an intermediary between the terminal device and the I-SMF. The AMF collects capability information of the I-SMF, determines whether it supports MBS, and based on this determination, either establishes the PDU session directly or triggers selection of a different I-SMF that supports MBS. This intermediary role allows the system to resolve the contradiction by making informed routing decisions
2Ease of operation
If an I-SMF that does not support MBS is selected, then the PDU session can be established, but data transmission must occur in unicast manner regardless of base station MBS support, resulting in low utilization of radio access network resources
Solution Approach 1:
The patent implements feedback mechanisms where the I-SMF provides capability information indicating whether it supports MBS. The AMF receives this feedback and uses it to determine the appropriate transmission mode. If the I-SMF does not support MBS, the AMF can trigger selection of a different I-SMF that does support MBS, ensuring that multicast/broadcast transmission can be used when appropriate, thereby improving network resource utilization
Solution Approach 2:
The patent introduces dynamic selection of I-SMF based on capability matching. Instead of a static assignment, the system dynamically determines whether to use an existing I-SMF or trigger selection of a different one that supports MBS. This dynamic approach allows the system to adapt to different scenarios and optimize for multicast/broadcast transmission when possible, resolving the contradiction between ease of session establishment and network resource utilization
Data Source
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AI summary
This application provides a multicast/broadcast communication method and a related apparatus. The method includes: A first session management function network element learns of multicast/broadcast capability information of an intermediate session management function network element corresponding to a first protocol data unit session of a terminal device; and if the intermediate session management function network element does not support a multicast broadcast service, the first session management function network element sends first information to an access and mobility management function network element, where the first information is for triggering the access and mobility management function network element to select, for the first protocol data unit session of the terminal device, at least one intermediate session management function network element that supports a multicast broadcast service. In this way, the access and mobility management function network element can effectively select the intermediate session management function network element that supports a multicast broadcast service. Therefore, a base station may transmit data to the terminal device in a multicast/broadcast manner, thereby saving network resources and improving network resource utilization.