PDN Connection Reset for LTE Resource Consistency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the LTE system, the release of Packet Data Network (PDN) connections can lead to inconsistencies between the information stored by the EPC and UE, resulting in resource wastage and reliability issues with data transmission, especially when the EPC initiates unsolicited releases or when the UE is unable to delete PDN connections due to rejection messages.
Innovation Solution
The method involves a UE sending a PDN release request message when connected to at least two PDNs, handling PDN release rejection messages by sending a disconnection request, and subsequently sending an attach request to reset up a PDN connection with the EPC, ensuring consistent PDN information and resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the EPC initiates a PDN release request actively due to insufficient resources, then resource utilization is improved, but information consistency between EPC and UE deteriorates when notification fails
Solution Approach 1:
The patent implements a feedback mechanism where the UE sends an uplink message containing context information of EPS bearer reception to confirm receipt of release requests. The EPC starts a timer (T3495) and waits for this feedback. If feedback is not received within the timer period, the EPC re-sends the release request or handles the inconsistency, ensuring information consistency is maintained through continuous feedback loops.
Solution Approach 2:
The patent applies preliminary action by having the EPC proactively initiate PDN release requests before resources are completely exhausted. The EPC sends bearer deleting requests to the eNB and UE in advance, allowing graceful resource management while maintaining synchronization through subsequent confirmation messages from the UE.
2Ease of operation
If the UE sends a PDN release request to the EPC, then connection management is improved, but data transmission reliability deteriorates when the EPC rejects the release request
Solution Approach 1:
The patent applies inversion by changing the UE's behavior when facing a release rejection. Instead of simply accepting the rejection and maintaining the connection, the UE inverts the approach by disconnecting all PDN connections and resetting the PDN connection. This reverse action resolves the inconsistency caused by the rejected release request and restores reliability.
Solution Approach 2:
The patent changes the PDN connection parameters by resetting the entire PDN connection when a release request is rejected. The UE transitions from the rejected connection state to a fresh PDN connection establishment, changing connection parameters such as IP addresses and bearer configurations to ensure consistency between UE and EPC states.
3Productivity
If the EPC deletes PDN connection resources locally without notifying the UE, then resource release speed is improved, but information consistency between EPC and UE deteriorates
Solution Approach 1:
The patent introduces the eNB as an intermediary in the PDN release process. The EPC sends bearer deleting requests through the eNB, which then forwards RRC connection reconfiguration messages to the UE. This intermediary mechanism ensures that the UE is properly notified of release requests while maintaining efficient resource management at the EPC side.
Solution Approach 2:
The patent implements feedback mechanisms where the UE sends confirmation messages (uplink messages containing context information of EPS bearer reception) to the EPC after receiving release requests. The EPC uses timers to track these feedback messages, ensuring that both sides have consistent information about PDN connection status while maintaining fast resource release capability.
Data Source
AI summary
The present disclosure provides a method, system and device for processing the release failure of a PDN. The method includes: a UE, when the UE determines that it currently connects with at least two PDNs, sends a PDN release request message to an EPC and then receives a release rejection message from the EPC, wherein a rejection reason is that the last PDN connection is not allowed to be released; and the UE releases each PDN connection with the EPC and then resets up a PDN connection with the EPC. Through the technical solution, the PDN connection information of the UE and that of the EPC are kept consistent, so that resources are saved and the reliability of data transmission is improved.