Cell Identifier Conflict Resolution in LTE Networks

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Solution Overview

Problem

In LTE cellular radio communications networks, cell identifier collisions occur due to limited unique signature sequences, leading to ambiguities in neighbor cell lists and disruptions in handover processes, especially in densely populated areas or during network expansions, where manual planning is challenging and automated solutions are needed to resolve these collisions efficiently and seamlessly.

Innovation Solution

An automated method is implemented to detect and resolve cell identifier collisions by selecting one conflicting cell to change its identifier, determining a new identifier, and disseminating it to other cells and user equipment without disrupting ongoing communications, using a detecting node that receives information from user equipment and neighbor cell relations to ensure seamless updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual planning is used to assign unique cell identifiers, then identifier uniqueness can be maintained, but the complexity and time required for network deployment and expansion increases significantly

Engineering Contradiction:
Improvecell identifier uniquenessVSAvoidnetwork planning complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system enables automated cell identifier assignment where base stations autonomously detect collisions and resolve them through self-organization. The detecting node automatically identifies conflicting identifiers and coordinates changes without manual intervention, allowing the network to self-configure during deployment and expansion.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system dynamically changes cell identifier parameters automatically when collisions are detected. The detecting node modifies the identifier of one conflicting cell to a different value, resolving the collision while maintaining uniqueness. This automated parameter adjustment eliminates the need for complex manual planning.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the number of unique signature sequences is increased, then cell identifier collision probability decreases, but the radio resource cost increases

Engineering Contradiction:
Improvecell identifier collision avoidanceVSAvoidradio resource consumption
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system extracts and reuses signature sequences that were previously reserved or unused, making them available for assignment to base stations. By utilizing previously闲置 resources rather than creating new ones, the system increases identifier availability without proportionally increasing radio resource consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system implements dynamic signature sequence assignment where identifiers are allocated and reassigned based on current network conditions and collision detection. This dynamic approach allows efficient utilization of the available signature sequence pool, maximizing the number of usable identifiers without requiring a static increase in total resources.

Inventive Principle:
Principle #15Dynamics

3Productivity

If automated collision resolution is implemented, then network deployment efficiency improves, but the system complexity and coordination requirements increase

Engineering Contradiction:
Improvenetwork deployment efficiencyVSAvoidcollision resolution system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The detecting node serves as an intermediary that coordinates the collision resolution process. It detects conflicts, selects which cell should change its identifier, determines appropriate new identifiers, and communicates decisions to affected base stations. This intermediary approach automates the complex coordination required for collision resolution while maintaining system manageability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary detection and resolution actions before conflicts impact network operations. By proactively identifying and resolving identifier collisions during the cell setup and handover processes, the system prevents service disruptions and eliminates the need for more complex reactive resolution mechanisms.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If cell identifier changes are made frequently to resolve collisions, then identifier uniqueness is maintained, but service disruptions and handover failures increase

Engineering Contradiction:
Improvecell identifier uniquenessVSAvoidservice disruption
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system applies preliminary anti-action by notifying user equipment of upcoming cell identifier changes before they take effect. This advance notification allows UEs to prepare for the change, update their internal records, and maintain continuous connectivity. The detecting node coordinates timing to ensure changes occur with minimal disruption to ongoing services.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The system implements feedback mechanisms where base stations report their current identifier status and UEs report measurement results that may indicate collisions. This continuous feedback loop allows the detecting node to make informed decisions about when and how to change identifiers, minimizing unnecessary changes and their associated disruptions while ensuring uniqueness is maintained.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2672750B1Cell identifier conflict resolution
Publication Date: 2016.05.11 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2672750B1 patent drawingFigure 1
  • EP2672750B1 patent drawingFigure 2
  • EP2672750B1 patent drawingFigure 3

AI summary

The technology described automatically resolves cell identify collisions/conflicts in a cellular radio communications network. A detecting node determines that a first cell identifier associated with a first conflicting cell is the same as a second cell identifier associated with a second conflicting cell. One of the first and second conflicting cells is selected to change its cell identifier. A different cell identifier is determined for the selected cell. The different cell identifier is then provided to other cells and preferably to user equipment (UE) terminals without disrupting ongoing UE communications.