Dual-Stack IP Session Recovery Without Preferred RAT Exit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dual stack IP devices experience connection delays and forced transitions to less-preferred radio access technologies (RATs) when attempting to connect to remote resources that only support one IP type, due to current network handling protocols that trigger deregistration and RAT exit.
Innovation Solution
Implementing a dual stack IP handler in the network node to intercept deregistration requests caused by IP type mismatches, allowing the user equipment (UE) to request a new packet data session without exiting its preferred RAT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cellular network sends a deregistration message to trigger UE to exit the preferred RAT when there is an IP type mismatch, then the UE can attempt connection on a lower RAT, but this introduces delay and forces the UE to use a less-referred RAT when the problem is not within the RAT
Solution Approach 1:
The patent introduces a new message type (e.g., PDU Session Establishment Reject or specific indication message) that acts as an intermediary between the network's IP type mismatch detection and the UE's session management. This message conveys the mismatch information to the UE without triggering RAT exit, allowing the UE to maintain its preferred RAT while being informed of the IP type incompatibility. The intermediary message prevents the harmful cascading effect of unnecessary RAT transitions while still communicating the network's position on the IP type mismatch.
2Reliability
If the UE exits the preferred RAT to attempt connection on a lower RAT due to IP type mismatch, then the connection can be established on the lower RAT, but the UE is forced to use a less-referred RAT when the problem is inside the cellular network core
Solution Approach 1:
The patent segments the error handling by distinguishing between RAT-related errors and core network-related errors. By introducing a specific message type that indicates IP type mismatch origin (core network vs. RAT), the system allows the UE to appropriately segment its response: maintaining the preferred RAT when the error is core-network-related, while still allowing RAT exit when the error is genuinely RAT-related. This segmentation prevents the conflation of different error types and their inappropriate uniform handling.
3Adaptability or versatility
If the network supports dual stack IP types, then the UE can support both IPv4 and IPv6, but this introduces challenges when the remote resource supports only one IP type
Solution Approach 1:
The patent implements a feedback mechanism where the network node provides explicit information to the UE about the IP type mismatch and its origin. The deregistration message or session establishment reject message includes indicators that feedback to the UE about whether the mismatch is due to remote resource limitations or network core limitations. This feedback allows the UE to make informed decisions about session establishment without the network needing to implement complex adaptive logic in the UE, thus managing complexity centrally while maintaining adaptability.
Data Source
AI summary
Solutions for improved network core handling of dual stack internet protocol (IP), such as IPv4v6, include receiving, by a first wireless network node, from a user equipment (UE), a request for a packet data session, the request identifying a dual stack IP type having a first IP type and a second IP type; based on at least the first IP type of the dual stack IP type not matching a supported IP type of a second wireless network node, receiving, by the first wireless network node, from the second wireless network node, a deregistration request for the UE; and transmitting, by the first wireless network node, to the UE, a message that triggers the UE to request a new packet data session without exiting the current radio access technology (RAT). In some examples, the first network node comprises an access mobility function (AMF) or a mobility management entity (MME).