Dual Registration Indication in Network Device Attach Procedures
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Solution Overview
Problem
Dual registration in 4G and 5G networks leads to issues where the UE context is arbitrarily canceled when attaching to either network, causing disruptions in IP connectivity and registration, especially during handovers between EPC and 5GC.
Innovation Solution
A network device and radio communication method that includes a connection processing unit to acquire attach requests and a registration processing unit to notify other network devices of dual registration indications, preventing unnecessary cancellation of UE context and maintaining dual registration by stopping notifications of connection indications when the UE is dually registered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs attach procedure to attach to EPC in dual registration mode, then the UE can connect to the first communication network, but the 5GC registration and IP connectivity are canceled
Solution Approach 1:
The patent introduces a new parameter 'dualRegistrationIndication' that changes the behavior of the attach procedure. When this indication is set, the MME modifies the attach process to preserve 5GC registration instead of canceling it, thus resolving the contradiction between maintaining dual registration and performing standard attach procedure
Solution Approach 2:
The patent uses the 'dualRegistrationIndication' as an intermediary signal between the MME and other network devices (HSS, AMF). This intermediary parameter communicates the dual registration state across network boundaries, enabling coordinated behavior that preserves both EPC and 5GC registrations during attach procedures
2Loss of information
If the network device notifies another network device of connection indication when UE is dually registered, then the connection status is tracked, but the UE context is unnecessarily canceled in the other network
Solution Approach 1:
The patent modifies the connection indication notification by introducing a conditional parameter 'dualRegistrationIndication'. When this parameter is true, the notification behavior changes to preserve UE context in both networks. This parameter-driven approach allows the system to track connection status without triggering unnecessary context cancellations in dual registration scenarios
Solution Approach 2:
Instead of the conventional approach where connection indication automatically triggers context cancellation in the other network, the patent inverts this logic by using the 'dualRegistrationIndication' to prevent cancellation. When dual registration is detected, the normal cancellation behavior is reversed, preserving context in both EPC and 5GC networks
Data Source
AI summary
A radio communication method according to the present invention supports Dual registration in which the same UE (50) is simultaneously registered on 4G and 5G. The radio communication method includes the UE (50) requesting connection to EPC and transmitting, to the 4G, Attach Request that includes Dual registration indication that indicates that the UE (50) has been dually registered, and MME (100) that constitutes the 4G notifying, after the Attach Request has been acquired, HSS (110) of the Dual registration indication that indicates that the UE (50) has been dually registered.