Gateway User Plane Split for Low-Latency Idle Downlink Delivery

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Solution Overview

Problem

The separation of control plane and user plane functions in a mobile communication system poses challenges in efficiently processing downlink traffic for user equipment in idle mode, leading to increased latency and resource inefficiency.

Innovation Solution

The system separates user plane nodes into a node for processing connected mode traffic and another for buffering idle mode traffic, using service chaining and buffering strategies to optimize data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If control plane and user plane are separated in gateway nodes, then network resource efficiency is improved, but downlink traffic processing for idle mode UE becomes complex and latency increases

Engineering Contradiction:
Improvenetwork resource efficiencyVSAvoidtraffic processing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The gateway node is segmented into control plane (CP) and user plane (UP) functions. The UP is further divided into multiple UP nodes with specialized roles: some UP nodes handle downlink traffic buffering for idle mode UEs, while others handle connected mode traffic forwarding. This segmentation allows each node to be optimized for specific functions, improving overall network resource efficiency while managing complexity through functional specialization.

Inventive Principle:
Principle #1Segmentation

2Loss of time

If downlink traffic is buffered at user plane node, then data transmission latency is reduced, but network resource overhead increases

Engineering Contradiction:
Improvedata transmission latencyVSAvoidnetwork resource overhead
Core Design Contradiction:
Loss of timeVSQuantity of substance

Solution Approach 1:

Different UP nodes are assigned different functional qualities based on local needs. Some UP nodes are configured with buffering capabilities for idle mode UEs, while others are optimized for connected mode traffic forwarding without buffering. This local quality differentiation allows the system to reduce latency for idle mode UEs by buffering at appropriate nodes, while avoiding unnecessary buffering overhead at nodes where it is not needed.

Inventive Principle:
Principle #3Local quality

3Reliability

If user plane nodes are divided into connected mode and idle mode nodes, then service quality is enhanced, but system complexity increases

Engineering Contradiction:
Improveservice qualityVSAvoiduser plane node complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The user plane is segmented into dedicated UP nodes for connected mode traffic and separate UP nodes for idle mode traffic buffering. This segmentation allows each node type to be optimized for its specific function, enhancing service quality by ensuring that idle mode UEs receive timely data delivery while connected mode UEs enjoy efficient traffic forwarding. The complexity is managed through clear functional separation and standardized interfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control plane acts as an intermediary that manages the interaction between different UP nodes. It handles the coordination of traffic routing decisions, determining when to buffer traffic at idle mode UP nodes and when to forward directly through connected mode UP nodes. This intermediary role of the CP simplifies the complexity of managing multiple UP node types by centralizing control logic.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3843456B1Method and gateway for transmitting downlink packet in function-separated core network
Publication Date: 2026.04.22 SK TELECOM CO LTD
  • EP3843456B1 patent drawingFigure 1
  • EP3843456B1 patent drawingFigure 2
  • EP3843456B1 patent drawingFigure 3

AI summary

The present invention discloses method for transmitting downlink packet in function-separated core network. It is an object of the embodiments of the present disclosure to provide a method for transmitting a downlink packet for a UE in an idle mode which is capable of reducing a data transmission latency for a user and efficiently using network resources in a mobile communication system in which the control plane and the user plane of a gateway node are separated.