Bandwidth-Based Cell Selection in GSM Networks

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Solution Overview

Problem

Current cell re-selection methods in GSM networks are inefficient for packet-based GPRS/EDGE communications, as they lack agile handover mechanisms, leading to difficulties in maintaining data transfers across multiple cells due to varying signal quality and system information lengths.

Innovation Solution

A method that incorporates bandwidth assessments as a parameter for cell selection and re-selection, using signal strength and capacity indications to choose cells with optimal capacity and signal quality, ensuring robust data communication by multiplying capacity and signal strength metrics for each cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If cell re-selection is based solely on signal strength (RSSI), then the method is simple and compatible with existing GSM infrastructure, but packet-based data transfer reliability deteriorates due to lack of agile handover mechanisms

Engineering Contradiction:
Improvecell re-selection mechanism complexityVSAvoidpacket-based data transfer reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention changes the selection parameter from only signal strength (RSSI) to a composite metric that includes both signal strength and available bandwidth/capacity. This allows the system to maintain simplicity in measurement while improving reliability by considering network conditions that affect data transfer performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic cell re-selection based on real-time bandwidth availability and signal strength measurements. The mobile station continuously monitors both parameters and can rapidly switch cells when conditions deteriorate, creating an agile handover mechanism for packet-based communications without requiring network infrastructure changes.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the mobile station waits for system information transmission before cell re-selection, then it can avoid misinterpreting transmission time as poor quality, but data transfer efficiency deteriorates due to delays in cell switching

Engineering Contradiction:
Improvequality of service interpretation accuracyVSAvoiddata transfer efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention performs preliminary measurements of both signal strength and bandwidth availability before system information transmission completes. The mobile station has these metrics ready in advance, allowing immediate cell re-selection decisions without waiting for system information, thus maintaining both accuracy and efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses feedback from bandwidth measurements and signal strength monitoring to make informed cell re-selection decisions. The mobile station continuously receives feedback about network conditions and uses this information to proactively switch cells before service degradation occurs, improving both accuracy and efficiency.

Inventive Principle:
Principle #23Feedback

3Reliability

If multiple adjacent timeslots are assigned on adjacent cells, then data transfer robustness improves through diversity, but the probability of finding suitable cells deteriorates due to difficulty in locating multiple adjacent cells with appropriate conditions

Engineering Contradiction:
Improvedata transfer robustnessVSAvoiddifficulty of finding suitable adjacent cells
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The invention applies local quality assessment by evaluating bandwidth and signal strength characteristics of individual cells and their neighbors. The mobile station identifies specific cells with favorable local conditions and can assign multiple timeslots on these selected cells, achieving robustness without requiring extensive searches across many cells.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP1954077B1Bandwidth-based cell selection in a cellular network
Publication Date: 2012.07.04 BLACKBERRY LTD
  • EP1954077B1 patent drawingFigure 1
  • EP1954077B1 patent drawingFigure 2
  • EP1954077B1 patent drawingFigure 3

AI summary

A method of cell selection in a wireless cellular network having a plurality of radio system cells involves determining a bandwidth indication for data communication through each of a serving cell and at least one neighbouring cell to the serving cell. The bandwidth indication comprises an indication of the capacity for data communication through each cell. One of the cells is then selected for packet-based communication in accordance with the determined bandwidth indications.