Multi-Access PDN Connection Control via NBIFOM and ESM Cause
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Solution Overview
Problem
The detailed procedure for establishing a multi-access PDN connection in Network-based IP Flow Mobility (NBIFOM) has not been stipulated, particularly for successful and failure scenarios, and the acceptance or rejection mechanisms from the network are not clearly defined for terminal devices supporting NBIFOM.
Innovation Solution
A terminal device and network entities, such as the Mobility Management Entity (MME) and PDN Gateway (PGW), transmit specific messages with Protocol Configuration Options (PCO) and Error Status Message (ESM) Cause values to manage PDN connectivity requests, allowing for the establishment or rejection of multi-access PDN connections based on supported NBIFOM functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the network supports NBIFOM function for multi-access PDN connection, then the terminal device can simultaneously utilize 3GPP and non-3GPP interfaces, but the procedure for establishing multi-access PDN connection is not clearly defined
Solution Approach 1:
The patent segments the PDN connection establishment procedure into distinct phases: initial PDN connection establishment via 3GPP interface, and subsequent multi-access PDN connection establishment. Each phase has clearly defined message exchanges and acceptance/rejection criteria, breaking down the complex multi-access procedure into manageable steps with specific ESM Cause values for different scenarios.
Solution Approach 2:
The patent establishes preliminary conditions and procedures before enabling multi-access functionality. The terminal device first establishes a basic PDN connection through the 3GPP interface, and only after this initial connection is confirmed does the multi-access PDN connection procedure begin. This preliminary action ensures a stable foundation before adding complexity.
2Reliability
If the network defines detailed accept and reject procedures for multi-access PDN connection, then the communication control is improved, but the message exchange complexity increases
Solution Approach 1:
The patent uses ESM Cause parameter changes to differentiate between various acceptance and rejection scenarios. Specific ESM Cause values indicate different outcomes (e.g., multi-access not allowed, NBIFOM not supported), allowing the network to convey detailed control decisions through standardized parameters rather than complex custom message structures.
Solution Approach 2:
The patent introduces the PCO (Protocol Configuration Option) as an intermediary element that carries NBIFOM capability information between the terminal device and network. This intermediary simplifies the interaction by providing a standardized mechanism for capability negotiation without requiring complex direct negotiation protocols.
3Ease of operation
If the terminal device requests multi-access PDN connection with NBIFOM support, then the network can control the connection establishment, but the rejection procedure is not clearly defined
Solution Approach 1:
The patent implements a feedback mechanism where the network provides specific ESM Cause values in rejection messages to explain why a multi-access PDN connection request was denied. Different ESM Cause values convey different rejection reasons (e.g., multi-access not allowed, NBIFOM not supported by network), ensuring that termination information is not lost and the terminal device understands the rejection rationale.
Data Source
AI summary
Communication control in response to establishment of a multi-access PDN connection or rejection of establishment of a multi-access PDN connection is performed based on a response to a PDN connectivity establishment request from a terminal device. This provides a method of communication control and the like in response to a multi-access PDN connectivity establishment request from the terminal device.