Cell Reselection Parameter Segmentation for Radio Access Load Sharing

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Solution Overview

Problem

Current mobile radio access networks lack the ability to flexibly and individually distribute user terminals between different radio access technologies, leading to inefficient data traffic management and increased latency when switching between technologies like UTRAN and E-UTRAN, particularly for data services.

Innovation Solution

A method is introduced where the network selectively signals parameters to influence the cell reselection process of mobile terminals, allowing for UE-specific RAT selection between technologies like LTE, UMTS, GERAN, or WLAN, using dedicated RRC signaling or broadcast channels, with configurable offset parameters and timers to steer terminals efficiently between radio access technologies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If UE-controlled cell reselection algorithms operate independently of subscriber-specific considerations using broadcast parameters, then all user equipments are handled uniformly with simple implementation, but service differentiation and flexible traffic steering between GERAN and UTRAN cannot be achieved

Engineering Contradiction:
Improveservice differentiation capabilityVSAvoidcell reselection algorithm complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the cell reselection parameter set into two distinct groups: broadcast parameters (common for all UEs) and dedicated parameters (specific to individual UEs or service types). This segmentation allows the system to maintain simple broadcast-based operation for general cases while enabling complex service-specific steering through dedicated parameter sets transmitted via dedicated signaling when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by providing different parameter sets to different UEs based on their specific service requirements, subscriber profiles, or traffic types. Instead of uniform treatment, the network can assign customized offset values, threshold parameters, or frequency priorities to specific UEs, enabling localized optimization for voice traffic versus data traffic or for different service classes.

Inventive Principle:
Principle #3Local quality

2Speed

If network controls mobility in CELL_DCH state with dedicated physical channels, then service-specific traffic steering can be performed, but network switching delay increases when users need to switch between radio access technologies

Engineering Contradiction:
Improvenetwork switching speedVSAvoidcall set-up time
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent implements preliminary action by configuring cell reselection parameters in advance during idle mode or earlier connection states, so that when traffic steering is needed, the UE is already prepared with the appropriate parameters for rapid execution. The network can pre-configure offset values and thresholds that enable fast switching without requiring full CELL_DCH state transitions, thereby reducing both switching delay and call set-up time.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If users are steered to alternative network using directed retry during call set-up, then traffic can be distributed between networks, but location updates and paging outages occur when users return to UE-controlled cell reselection

Engineering Contradiction:
Improvetraffic distribution efficiencyVSAvoidservice continuity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where the network continuously monitors UE location, service type, and network load conditions, then dynamically adjusts dedicated cell reselection parameters to maintain optimal traffic distribution. This feedback loop ensures that when users return to UE-controlled mode, the pre-configured parameters guide them back to appropriate networks without triggering location updates or causing paging outages, thereby maintaining both traffic distribution efficiency and service continuity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP1835780B1Load sharing in mobile radio access networks using modified parameters for cell reselection by dedicated signalling
Publication Date: 2019.10.09 T MOBILE INTERNATSIONAL AG
  • EP1835780B1 patent drawingFigure 1
  • EP1835780B1 patent drawingFigure 2
  • EP1835780B1 patent drawingFigure 3a~3b

AI summary

The User-Equipment-controlled cell reselection algorithms in a UMTS or GERAN system currently operate independently of any subscriber-specific or service considerations. All user equipments, UE, are handled in the same way. In the case that any service or subscriber differentiation is required, e.g. for traffic steering between UTRAN and GERAN, this is typically performed once the UE has entered the UMTS CELL_DCH RRC state in which the network controls the mobility of terminal individually. The proposed invention allows the mobile radio network to signal to certain mobiles an offset which is applied on the normal cell reselection parameters in order to selectively change the cell reselection behaviour of specific mobile terminals. This allows for example to steer some mobiles, e.g. depending on the used service, subscription, terminal capabilities etc., from one radio access technology to another based on changed cell reselection parameters.