PLMN Selection for Multi-Access Network Connectivity

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Solution Overview

Problem

Current PLMN selection procedures for multi-interface terminals are independent across different access technologies, limiting network mobility and traffic offload capabilities, as they do not consider the terminal's multiple-interface capability or network policies, leading to separate connections and restricted traffic steering between access networks.

Innovation Solution

A generalized PLMN selection mechanism that coordinates PLMN selection across multiple access technologies, minimizing the number of registered PLMNs and utilizing stored information to optimize connectivity, allowing operators to manage traffic flows by selecting PLMNs that provide access to the largest number of technologies and adhering to network policies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If independent PLMN selection procedures are used for each access technology, then the selection process is simple and follows existing standards, but the terminal connects to multiple different PLMNs across different accesses and network traffic cannot be steered between accesses

Engineering Contradiction:
ImprovePLMN selection procedure simplicityVSAvoidNetwork traffic steering capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent merges the PLMN selection processes of multiple access technologies by introducing a master PLMN selection that coordinates selections across all accesses. The terminal now selects a master PLMN once, and this master PLMN is used as the reference for all other access technologies, combining what were previously independent selection procedures into a unified approach.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The master PLMN selection serves multiple functions: it acts as the primary PLMN for the terminal, provides the basis for selecting PLMNs on other accesses, enables network traffic steering across accesses, and allows operators to apply policies across the entire multi-access terminal. This single selection mechanism performs what previously required multiple independent selections.

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

2Adaptability or versatility

If separate PLMN lists are maintained for different access technologies, then each access can be configured independently, but the number of registered PLMNs increases and network management becomes complex

Engineering Contradiction:
ImproveAccess-specific PLMN configurationVSAvoidPLMN list management
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent consolidates multiple access-specific PLMN lists into a single master PLMN list. Instead of maintaining separate lists for 3GPP and non-3GPP accesses, the terminal now maintains one master list from which all access-specific selections are derived, significantly reducing the complexity of PLMN list management while still allowing access-specific configurations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The master PLMN selection is performed first as a preliminary step before any access-specific PLMN selections are made. This preliminary action establishes a reference point that simplifies subsequent selections on other accesses, as they can now reference the master PLMN rather than requiring independent selection logic.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If each access technology performs independent PLMN selection, then the terminal can connect to available networks on each access, but flow mobility among access networks is limited due to policies being applicable only within operator domains

Engineering Contradiction:
ImproveNetwork connectivityVSAvoidFlow mobility across accesses
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The master PLMN selection creates a universal reference point that enables operators to apply network policies across all access technologies. By ensuring all accesses are connected to the same master PLMN or equivalent PLMNs, the system enables flow mobility and traffic steering between accesses, as policies can now be applied uniformly across the entire multi-access terminal rather than being restricted to individual operator domains.

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

Data Source

PatentEP2524525B1Public land mobile network selection procedures for simultaneous network connectivity through multiple accesses
Publication Date: 2015.10.21 KK TOSHIBA
  • EP2524525B1 patent drawingFigure 1
  • EP2524525B1 patent drawingFigure 2
  • EP2524525B1 patent drawingFigure 3

AI summary

A system and method for network selection procedures for simultaneous network connectivity through multiple accesses comprises obtaining stored and registered PLMNs, determining whether PLMNs are both stored PLMN for access technology type Ai and registered PLMN, when no PLMNs are both, performing PLMN selection using a standard procedure, when only one PLMN is both, determining whether the PLMN satisfies a condition, and when the PLMN satisfies the condition, attempting to connect to the PLMN, and when more than one PLMN is both, creating a set of PLMNs, selecting one PLMN that satisfies the condition, from the set PLMN, attempting to connect to the selected PLMN, and when attempting to connect fails, removing the selected PLMN from the set, and selecting another PLMN. In one aspect, the PLMN that minimizes changes is selected. In one aspect, the PLMN that provides access to a larger number of access technologies is selected.