Cellular Handover via Sector-Specific Neighbor Lists

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Solution Overview

Problem

In cellular networks with small cell sizes, especially in urban areas, the handover process from a serving base station to a new one is delayed due to the need for accurate signal strength measurements from a large number of neighboring base stations, which can lead to either prolonged measurement times or reduced accuracy, risking communication disruption.

Innovation Solution

The method involves partitioning the radio coverage cell into sectors, with each sector having a list of neighboring base stations whose coverage overlaps the serving base station's area, allowing the serving base station to transmit a selected list based on the mobile station's location, reducing the number of stations to measure and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the mobile station measures signal strength from all neighboring base stations in the neighbor list, then the selection accuracy is improved, but the measurement time increases

Engineering Contradiction:
Improvesignal strength measurement accuracyVSAvoidobservation phase duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The neighbor list is segmented into multiple subsets based on geographic sectors. Each subset contains only the neighboring base stations relevant to a specific sector. The mobile station receives only the subset corresponding to its current sector, thereby reducing the number of measurements required while maintaining accuracy for the relevant area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sectors of the serving base station coverage area are assigned different neighbor list subsets tailored to their specific geographic characteristics. Each sector has a customized list containing only the neighboring base stations that are actually relevant to that local area, rather than using a single comprehensive list for all sectors.

Inventive Principle:
Principle #3Local quality

2Productivity

If the cell size is reduced to increase network capacity, then the throughput is improved, but the number of handovers increases

Engineering Contradiction:
Improvenetwork throughputVSAvoidhandover management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

By segmenting the neighbor list into sector-specific subsets, the system reduces the measurement burden during each handover event. This makes the handover process more efficient and manageable even when handovers occur frequently due to small cell sizes, thereby supporting high network capacity without overwhelming the handover management complexity.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If a comprehensive neighbor list is transmitted to all mobile stations, then the coverage is improved, but the message size increases

Engineering Contradiction:
Improveneighbor list coverageVSAvoidmessage size
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

Each sector receives a customized neighbor list subset that is appropriate for its specific geographic area. This provides locally optimized coverage information to each mobile station based on its sector location, rather than transmitting a single comprehensive list to all stations. The overall system maintains comprehensive coverage capability while each individual message remains compact.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2227056B1Method for enhancing the handover of a mobile station and base station for carrying out the method
Publication Date: 2019.04.24 ALCATEL LUCENT SA
  • EP2227056B1 patent drawingFigure 1a~2a
  • EP2227056B1 patent drawingFigure 1b~2b
  • EP2227056B1 patent drawingFigure 3

AI summary

The invention concerns a method for enhancing the handover of a mobile station (20-23) from a serving base station (1) of a cellular network to a new base station, the new base station is selected among a neighbor list including neighboring base stations, the radio coverage cell (r2-r8) of which overlaps the radio coverage cell (r1) of said serving base station (1). It is also provided the base station for carrying out the method. According to the invention it is determined a current sector (s1-s3; s1-s6) in which said mobile station (20-23) is located among a plurality of sectors (s1-s3 ; s1-s6) partitioning the radio coverage cell (r1) of said serving base station (1), and the neighbor list includes only the neighboring base stations the radio coverage cell (r2-r8) of which overlaps said current sector (s1-s3; s1-s6).