Base Station Neighbor List Management for PLMN Availability

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Solution Overview

Problem

In multi-operator wireless communication networks, existing technologies fail to efficiently manage the availability of served Public Land Mobile Networks (PLMNs) between base stations, leading to temporary unavailability and improper handover decisions due to loss of PLMN connectivity, resulting in unnecessary removal of network performance data and potential service disruptions.

Innovation Solution

A method is implemented where a base station receives messages indicating the availability of PLMNs from neighboring cells, removing them from the neighbor list only when no PLMNs are available, while retaining performance data for potential future restoration, and reinstating links when PLMNs become available again, using the X2 interface to manage handover targets and maintain accurate network performance data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a base station removes a neighboring cell from its neighbor list when no served PLMNs are available, then handover decisions are prevented from targeting unavailable cells, but network performance data for that cell is discarded, causing loss of information and potential service disruptions when PLMN availability is restored

Engineering Contradiction:

Improvehandover decision accuracyVSAvoidnetwork performance data

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the neighbor list into two distinct components: (1) the cell list that tracks PLMN availability status for handover decisions, and (2) the performance data store that preserves historical network performance information. This segmentation allows the system to remove cells from the cell list when no PLMNs are available while retaining their performance data, thus preventing incorrect handover decisions without losing valuable historical information.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a selective discarding mechanism where neighboring cells are removed from the cell list (not permanently discarded) when no served PLMNs are available. The system retains performance data for these cells and can recover by reinstating them to the cell list when PLMN availability is restored, enabling seamless service recovery without data loss.

Inventive Principle:

Principle #34Discarding and recovering

2Quantity of substance

If a base station removes performance data for a neighboring cell when it is removed from the neighbor list, then storage resources are freed, but the ability to restore service quickly when PLMNs become available is impaired

Engineering Contradiction:

Improvestorage resource utilizationVSAvoidservice restoration time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent performs preliminary action by continuously maintaining and updating performance data for neighboring cells in advance, even when they are temporarily removed from the cell list due to PLMN unavailability. This pre-retention of performance data eliminates the need for time-consuming data recollection and reconstruction when service restoration is needed, allowing for rapid service recovery.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If a base station maintains neighbor list information for cells with no available PLMNs, then future handover decisions can be made, but unnecessary handover attempts may be prepared and executed for unavailable cells

Engineering Contradiction:

Improvehandover flexibilityVSAvoidunnecessary handover attempts

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements a dynamic cell list management mechanism where the cell list is continuously updated based on real-time PLMN availability status. Cells are dynamically added or removed from the cell list according to whether served PLMNs are currently available, enabling the system to adapt to changing network conditions and prevent unnecessary handover attempts while maintaining flexibility when PLMNs become available.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8891488B2Inter-base-station interface enhancement for multi-operator core networks

Publication Date: 2014.11.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

In one aspect, the teachings herein provide an enhanced inter-base-station interface and associated processing in which a base station receives a message from a neighboring base station that zero served PLMNs are available in a neighboring cell. In response to receiving that message, the base station removes the neighboring cell from its neighbor list, or otherwise marks the neighboring cell as unavailable, but advantageously does not discard any network performance data accumulated or otherwise generated for that neighboring cell. Correspondingly, should the base station receive a subsequent message indicating that one or more served PLMNs have become available in the neighboring cell, it restores the neighboring cell to its neighbor list and reinstates links or associations, as needed, to the retained network performance data.