LTE Neighbor List Update via Zero Handover Detection
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Solution Overview
Problem
In LTE networks deployed in a popcorn fashion, handover failures occur due to out-of-date neighbor lists, where cells with the same Physical Cell Identity (PCI) are not uniquely identified, leading to incorrect handover executions and dropped calls.
Innovation Solution
A master neighbor list is maintained by the core network to identify cell pairs with zero handover counts, determine distances, and update the source neighbor list by adding newly deployed cells with matching PCI and removing incorrect entries, ensuring accurate handover operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If neighbor lists are maintained statically without frequent updates, then network operation simplicity is improved, but handover reliability deteriorates due to out-of-date neighbor information
Solution Approach 1:
The system performs periodic updates of neighbor lists by identifying cell pairs with zero handover counts at regular intervals, determining distances, and updating source neighbor lists with newly deployed cells. This periodic action ensures neighbor information remains current without requiring continuous updates, balancing operational simplicity with handover reliability.
Solution Approach 2:
The system uses handover count feedback to identify outdated neighbor relationships. By monitoring handover counts for cell pairs and detecting when they remain at zero despite network changes, the system triggers updates only when necessary, maintaining reliability while avoiding unnecessary operations.
2Reliability
If neighbor lists are updated frequently to maintain accuracy, then handover reliability is improved, but network operation complexity increases
Solution Approach 1:
Instead of updating all neighbor lists comprehensively, the system performs partial updates by identifying only cell pairs with zero handover counts and updating only those specific source neighbor lists that contain outdated entries. This selective approach maintains handover reliability while minimizing operational complexity.
Solution Approach 2:
The system automatically identifies outdated neighbor relationships and performs updates without requiring manual intervention. By self-managing the neighbor list maintenance process through automated detection of zero handover count cell pairs and distance-based updates, the system improves reliability without increasing operational complexity.
3Device complexity
If cells with same PCI are not uniquely identified, then neighbor list management is simplified, but handover accuracy deteriorates leading to incorrect handover executions
Solution Approach 1:
The system applies local quality by uniquely identifying cells with the same PCI through distance measurements from source cells. Instead of treating all cells with a given PCI uniformly, the system determines the specific cell that is geographically closest to the source cell, ensuring accurate handover execution while maintaining simplified PCI-based neighbor list management.
4Measurement precision
If distance calculation is performed for all cell pairs, then neighbor list accuracy is improved, but processing time increases
Solution Approach 1:
The system performs distance calculations only for cell pairs with zero handover counts rather than all cell pairs. By limiting distance calculations to only those cell pairs that are likely to contain outdated information, the system achieves necessary neighbor list accuracy while significantly reducing processing time.
Data Source
AI summary
Systems, methods, and computer-readable media for updating an out-of-date source neighbor list. In embodiments, the method includes maintaining a master neighbor list comprising a plurality of neighbor lists created by self-organizing network (SON) Automatic Neighbor Relation (ANR). Cell pairs in the master neighbor list with zero handover counts are identified. Each cell pair may comprise a source cell and a potential neighbor cell. A distance between each source cell and each corresponding potential neighbor cell having zero handover counts is determined. For each cell pair, a PCI (Physical Cell Identity) associated with a potential neighbor cell is identified. For each potential neighbor cell, an identity of a source neighbor cell in a source neighbor list corresponding to each source cell is determined, wherein the source neighbor cell having and the potential neighbor cell have a matching PCI. The distance between the source cell and the source neighbor cell is determined.