UE Bearer Synchronization via TAU for PDN Reconnection
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Solution Overview
Problem
In wireless communication systems, particularly in LTE networks, there is a challenge with bearer synchronization between user equipment (UE) and the network, leading to potential rejections of connection requests when a UE disconnects from a packet data network (PDN) during data throttling, causing the UE and network to become out of sync.
Innovation Solution
The UE initiates a Tracking Area Update (TAU) procedure to synchronize its bearer status with the network either immediately or upon expiration of a throttling timer if the disconnection occurred during data throttling, or checks for unexpected active radio bearers and performs a TAU to resolve synchronization issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE disconnects from PDN locally during data throttling without notifying the network, then the UE can quickly disconnect from the PDN, but the network and UE become out of sync leading to rejection of reconnection requests
Solution Approach 1:
The UE performs a Tracking Area Update (TAU) procedure as a preliminary action before attempting to reconnect to the PDN. This TAU procedure proactively synchronizes the UE's bearer status with the network, ensuring that when the reconnection request is subsequently made, the network and UE are in sync, thereby preventing rejection of the reconnection request.
2Reliability
If the UE performs TAU procedure immediately upon local PDN disconnection, then synchronization between UE and network is maintained, but unnecessary TAU procedures increase signaling overhead and network load
Solution Approach 1:
The UE changes its behavior based on the state of the throttling timer. When the throttling timer is active, the UE delays the TAU procedure until the timer expires. When the throttling timer is not active, the UE can perform TAU immediately or based on other conditions. This parameter-based decision-making optimizes the balance between maintaining synchronization and reducing unnecessary signaling.
3Reliability
If the UE checks for unexpected active radio bearers before reconnection, then synchronization issues can be detected and resolved, but the reconnection process becomes more complex and time-consuming
Solution Approach 1:
The UE implements a feedback mechanism by checking for unexpected active radio bearers before attempting reconnection to the PDN. This check provides feedback about the synchronization state between the UE and network. Based on this feedback, the UE decides whether to perform a TAU procedure before reconnection, thereby resolving synchronization issues while avoiding unnecessary complexity when no synchronization problem exists.
Data Source
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AI summary
Certain aspects of the present disclosure relate to methods and apparatus for improving data service availability. Certain aspects provide methods and apparatus for wireless communications by a UE including determining, while the UE is in a coverage area of a first network, that a connection to a second network, comprising a packet data network (PDN), is disconnected locally, and taking at least one action to avoid a rejection of a request to connect to the second network.