Coordinated UPF and PPF Selection for 5G Routing Optimization

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Solution Overview

Problem

In 5G networks, the uncoordinated selection of User Plane (UP) Functions (UPFs) and Packet Processing Functions (PPFs) leads to non-optimal routing of user data traffic, resulting in increased latency and extra transport costs due to unnecessary paths, known as tromboning, which is not addressed by existing technologies.

Innovation Solution

A method and system for coordinated selection of UPFs and PPFs in a cellular communications network, where information about the selected UPF is used to choose the optimal PPF based on criteria such as load and location, enabling efficient routing by informing the Radio Access Network (RAN) about the UPF selection for optimal PPF selection, and vice versa, to establish a direct tunnel between UPF and PPF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If UPF and PPF selection are performed independently without coordination, then each function can be selected based on its own criteria, but this leads to non-optimal routing paths (tromboning) and increased latency

Engineering Contradiction:

ImproveIndependent selection flexibilityVSAvoidRouting latency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The SMF performs UPF selection first and communicates the selected UPF identity and location information to the RCF before PPF selection. This preliminary action enables the RCF to make an informed PPF selection that coordinates with the UPF choice, avoiding non-optimal routing paths and reducing latency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback mechanism where the SMF provides UPF selection information (identity, location) to the RCF, which then uses this feedback to make coordinated PPF selection. This feedback loop ensures that both selections work together to optimize routing performance.

Inventive Principle:

Principle #23Feedback

2Device complexity

If UPF and PPF are selected independently, then selection complexity for each function is reduced, but this results in extra transport costs due to non-optimal routing paths

Engineering Contradiction:

ImproveSelection process complexityVSAvoidTransport cost

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The SMF performs UPF selection and communicates the selection results including location information to the RCF before PPF selection. This preliminary action provides the RCF with necessary information to select a PPF that minimizes transport distance and cost, rather than selecting independently.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The coordination mechanism creates a feedback loop where UPF selection information flows to the RCF, enabling the RCF to optimize PPF selection based on actual routing implications. This feedback ensures transport efficiency without significantly increasing selection complexity.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If CP and UP are logically separated in the RAN, then flexibility and scalability are improved, but this creates the need for coordinated selection between RCF and PPF

Engineering Contradiction:

ImproveRAN architecture flexibilityVSAvoidSelection coordination complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The N2 interface serves as an intermediary mechanism between the SMF (core network) and RCF (RAN). The SMF communicates UPF selection information through this interface, enabling coordinated PPF selection without requiring complex direct integration between RCF and PPF selection processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system maintains logical separation of CP and UP functions in the RAN while managing their coordination through distinct interfaces and procedures. The RCF handles control plane functions and selects PPF based on UPF information received from the core network, keeping the selection processes segmented but coordinated.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3602978B1Coordinated selection of user plane functions in core and radio access networks

Publication Date: 2022.10.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

Systems and methods are disclosed herein for coordinated selection of a User Plane Function (UPF) in a core network and a Packet Processing Function (PPF) in a radio access network. In some embodiments, a method of operation of network node of a cellular communications network to enable coordinated UPF and PPF selection comprises receiving information indicative of a UPF selected for a protocol data unit session of a wireless device, where the UPF is part of a core network of the cellular communications network. The method further comprises selecting a PPF for the protocol data unit session of the wireless device based on the information indicative of the UPF selected for the protocol data unit session of the wireless device, where the PPF is part of a radio access network of the cellular communications network. In this manner, an optimal routing of user data traffic can be achieved.