HSS SRVCC Ability Information Distribution for IMS Anchoring

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Solution Overview

Problem

The IMS network elements lack SRVCC ability information of user equipment, leading to unnecessary session and media anchoring, resulting in resource waste and potential voice interruptions during network switching.

Innovation Solution

The Home Subscriber Server (HSS) obtains and communicates user equipment ability information, such as SRVCC capabilities, to IMS network elements like ATCF and SCC AS, enabling informed decisions on session anchoring and reducing resource waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If IMS network elements perform session and media anchoring without SRVCC ability information, then service coverage is ensured, but network resources are wasted

Engineering Contradiction:
Improveservice coverageVSAvoidnetwork resources
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The HSS obtains SRVCC ability information from the UE in advance during the attach procedure and stores it in the subscriber data. This preliminary action allows IMS network elements to make informed anchoring decisions later without wasting resources on UEs that don't support SRVCC.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The HSS acts as an intermediary that collects SRVCC ability information from the UE and makes this information available to IMS network elements (S-CSCF, P-CSCF, ATCF) through standardized interfaces. This mediator approach allows distributed decision-making while avoiding resource waste.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If IMS network elements perform session anchoring for all users, then voice continuity is ensured, but voice interruptions occur during network switching

Engineering Contradiction:
Improvevoice continuityVSAvoidvoice interruption time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system applies different anchoring strategies based on the local quality of the UE - specifically whether the UE has SRVCC ability. UEs with SRVCC ability receive anchoring configuration that enables voice continuity during switching, while UEs without SRVCC ability receive standard anchoring. This localized differentiation avoids unnecessary voice interruptions.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the HSS obtains SRVCC ability information from the UE, then correct anchoring decisions are made, but additional signaling is required

Engineering Contradiction:
Improveanchoring decision accuracyVSAvoidsignaling complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The SRVCC ability information is merged with the existing subscriber data stored in the HSS. The HSS utilizes its existing data structures and interfaces to store and transmit this ability information, combining multiple functions into a unified system rather than creating separate signaling channels.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The HSS performs multiple functions: it stores subscriber data, obtains SRVCC ability information from UEs, and provides this information to IMS network elements. This multi-functionality approach avoids adding separate dedicated systems for ability information collection and distribution.

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

Data Source

PatentEP2549796B1Method and system for obtaining user equipment ability by user equipment, home subscriber data server and core network element
Publication Date: 2021.10.20 ZTE CORP
  • EP2549796B1 patent drawingFigure 1
  • EP2549796B1 patent drawingFigure 2~3
  • EP2549796B1 patent drawingFigure 4~5

AI summary

The present invention discloses user equipment, a home subscriber data server (HSS) and a method and system for obtaining user equipment ability by a core network element. Wherein, the method for obtaining user equipment ability by the core network element includes: in and/or after the IP multimedia network subsystem (IMS) registration process, the home subscriber data server (HSS) informing the IMS network element of the ability information of user equipment (UE). The HSS is enabled to obtain the user equipment ability information in present invention, and can provide services for various operations of subscribers.