IMS UE Registration Using SIP Low Access Priority Signaling

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Solution Overview

Problem

Existing communication networks fail to differentiate between User Equipments (UEs) using low access priority in the Internet Protocol based Multimedia Subsystem (IMS), leading to issues with voice service availability and inability to utilize low access priority information for IMS purposes such as prioritization, charging, and network selection.

Innovation Solution

A method where User Equipment (UE) includes a low access priority indication in the Session Initiation Protocol (SIP) register message to inform the IMS network of its access priority, allowing the IMS network to recognize and utilize this information for prioritization, charging, and network selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the IMS network does not differentiate between UEs using low access priority and normal priority, then the network operation is simpler, but voice service availability deteriorates and proper charging cannot be implemented

Engineering Contradiction:
Improvenetwork operation complexityVSAvoidvoice service availability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the UE population into different priority groups (low access priority and normal priority) by introducing a specific indication in the SIP REGISTER message. This segmentation allows the IMS network to differentiate between UEs and apply appropriate handling, thereby ensuring voice service availability for prioritized UEs while maintaining simpler operations for the overall network through standardized message structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by enabling the IMS network to identify and selectively process UEs with low access priority indications. The network can then apply different quality levels locally - providing enhanced voice service guarantees to specific UEs while maintaining standard operations for others, thus improving voice service availability without requiring complete network redesign.

Inventive Principle:
Principle #3Local quality

2Reliability

If the IMS network differentiates between UEs with low access priority, then voice service availability and charging accuracy improve, but network complexity increases

Engineering Contradiction:
Improvevoice service availabilityVSAvoidnetwork operation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements universality by using the existing SIP REGISTER message structure to carry the low access priority indication. This multi-functional approach allows the same message to serve both registration purposes and priority indication purposes, thereby improving voice service availability without proportionally increasing network complexity through separate signaling mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies self-service by enabling UEs to automatically indicate their access priority in the SIP REGISTER message without requiring additional network configuration or manual intervention. This self-indication mechanism allows the IMS network to differentiate UEs and provide appropriate voice service guarantees while minimizing the operational complexity burden on network administrators.

Inventive Principle:
Principle #25Self-service

3Quantity of substance

If low access priority indication is not transmitted to the IMS network, then signaling overhead is reduced, but the network cannot perform proper prioritization and charging

Engineering Contradiction:
Improvesignaling overheadVSAvoidprioritization capability
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent merges the low access priority indication with the existing SIP REGISTER message, combining multiple functions (registration and priority indication) into a single signaling exchange. This approach enables the IMS network to perform prioritization and charging while minimizing additional signaling overhead, as the priority information is conveyed within the already-necessary registration signaling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The SIP REGISTER message serves multiple purposes: it performs the standard UE registration function and simultaneously conveys the low access priority indication. This multi-functionality allows the network to gain prioritization capability without proportionally increasing signaling overhead, as the same message structure carries both registration data and priority information.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If the UE transmits low access priority indication in SIP REGISTER message, then the IMS network can provide proper charging and prioritization, but the message complexity increases

Engineering Contradiction:
Improvecharging and prioritization capabilityVSAvoidmessage structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses the SIP REGISTER message to serve dual purposes: standard UE registration and conveying low access priority indication. This multi-functional use of an existing standardized message format enables the IMS network to implement charging and prioritization capabilities without requiring completely new message structures, thereby limiting the increase in message complexity while gaining enhanced functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of creating separate complex signaling messages for priority indication, the patent inverts the approach by embedding the priority indication within the already-necessary SIP REGISTER message. This inversion allows the network to gain charging and prioritization capabilities while actually reducing overall signaling complexity compared to implementing separate dedicated priority signaling mechanisms.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3669581B1Methods and devices for registering a user equipment, UE, with low access priority in an internet protocol based multimedia subsystem, IMS
Publication Date: 2025.07.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3669581B1 patent drawingFigure 1
  • EP3669581B1 patent drawingFigure 2
  • EP3669581B1 patent drawingFigure 3

AI summary

A method for registering a User Equipment, UE, with low access priority in an Internet Protocol based Multimedia Subsystem, IMS, network said method comprising the steps of receiving, by a Proxy-Call Serving Control Function, P-CSCF node comprised by said IMS network, a Session Initiation Protocol, SIP, Register message for registering said UE in said IMS network, determining, by said P-CSCF node, that said SIP Register message comprises an indication that said UE is using a low access priority, wherein said low access priority indicates at least a reduced priority for said UE for accessing network resources, and establishing, by said P-CSCF node, said registration of said UE with said determined low access priority indication. Complementary methods and devices for performing a method according to the invention are also presented herein.