Control Plane Gateway DDN Signaling Optimization
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Solution Overview
Problem
In the context of an evolved packet system (EPS) network with control and user plane separation, the challenge lies in efficiently sending downlink data notification (DDN) messages across distributed gateway architectures, where the user plane gateway is unaware of the Mobility Management Entity (MME) to which a user equipment (UE) is registered, leading to increased signaling load and processing complexity.
Innovation Solution
A method where a control plane network element receives a delay instruction and an event report from a user plane network element, determining the UE's registration in an MME based on identifier information and routing information, and only sends the DDN message after a specified time period, thereby reducing signaling load and processing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control plane gateway sends DDN messages for every idle-state UE to the MME, then the MME can page all UEs, but the signaling load on the MME increases significantly
Solution Approach 1:
The control plane gateway performs partial action by selectively sending DDN messages only for UEs that are not currently connected to any base station, rather than sending DDN messages for all idle-state UEs. This reduces the number of DDN messages sent to the MME while ensuring that UEs needing paging are still notified, thus reducing signaling load while maintaining necessary reliability
Solution Approach 2:
The system implements feedback through the event report mechanism where base stations report idle-state UE information to the control plane gateway. The gateway uses this feedback to determine whether to send DDN messages based on current connection status, avoiding unnecessary signaling when UEs are already connected or becoming connected
2Device complexity
If the user plane gateway buffers downlink data for idle-state UEs, then data delivery is delayed, but signaling load on MME is reduced
Solution Approach 1:
The control plane gateway performs preliminary action by sending DDN messages proactively to the MME for UEs that are not connected, enabling the MME to page UEs before data arrives. This preliminary notification prevents data delivery delays while reducing the need for extensive buffering, as the paging mechanism is triggered in advance
Solution Approach 2:
The system dynamically adjusts data handling based on UE connection status. When UEs are idle and not connected, data is buffered with DDN notification sent. When UEs become connected, data is forwarded immediately. This dynamic approach optimizes both delivery time and signaling load based on real-time network conditions
3Measurement precision
If the control plane gateway determines MME registration for each downlink data packet, then DDN message accuracy improves, but processing complexity increases
Solution Approach 1:
The system segments the processing by separating the MME determination function from the base station connection status checking function. The control plane gateway maintains separate information structures for UE-MME associations and UE-base station associations, allowing efficient lookup and determination without complex processing for each data packet
Solution Approach 2:
The control plane gateway uses self-service by maintaining local context information about UE registrations and base station connections. Instead of querying the MME or base stations for each downlink data packet, the gateway uses its own stored information to rapidly determine whether to send DDN messages, reducing processing complexity while maintaining accuracy
Data Source
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AI summary
Embodiments of the present invention relate to the communications field, and in particular, to a downlink data notification message sending method, and an apparatus. The method is: receiving, by a control plane network element, a delay instruction sent by a mobility management network element, where the delay instruction is used to instruct the control plane network element to delay sending a DDN message; receiving, by the control plane network element, an event report message sent by a user plane network element, where the event report message includes a reported event, and the reported event is used to notify the control plane network element that a downlink data packet sent to user equipment UE matches no bearer; determining, by the control plane network element, that the UE is registered in the mobility management network element; and if the control plane network element has not received, within a first time period, routing information of a base station sent by the mobility management network element, sending, by the control plane network element, the DDN message to the mobility management network element when the first time period expires. According to the solutions of the embodiments of the present invention, DDN sending can be reduced, reducing signaling load of the mobility management network element, and further, processing complexity of the user plane network element can be lowered.