RAN Cell Restriction Status Global Messaging

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Solution Overview

Problem

In mobile radio communications systems like UMTS and LTE, there is a challenge in efficiently communicating cell restriction status changes to other RAN nodes, leading to delays and potential dropped connections due to inadequate access control and lack of systematic provision of access class information, which affects handover processes and emergency call availability.

Innovation Solution

Implementing a global, non-UE specific messaging system where RAN nodes inform each other of cell restriction status changes, using access class information to steer handovers and ensure appropriate cell access, and storing emergency call information to prioritize such calls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RAN nodes use traditional UE-specific messaging to communicate cell restriction status changes, then access control is maintained, but significant delays occur and handover failures increase

Engineering Contradiction:

Improvehandover success rateVSAvoidcell restriction status update delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the cell restriction status information communication by separating it from UE-specific messages. Instead of waiting for UE-specific handover messages to convey restriction status changes, the system uses dedicated global messages (SystemInformationBroadcast, SystemInformationModificationIndication) that are sent independently and immediately when restriction status changes occur. This segmentation eliminates the dependency on UE-specific messaging timing and ensures timely propagation of restriction status to all RAN nodes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by proactively sending global messages to inform RAN nodes of cell restriction status changes before any UE-specific handover attempts occur. When a cell's restriction status changes (e.g., from restricted to unrestricted), the serving RAN node immediately broadcasts this information via SystemInformationBroadcast or SystemInformationModificationIndication messages to neighboring RAN nodes, enabling them to update their local information and avoid failed handover attempts.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If RAN nodes do not systematically provision access class information, then device complexity is reduced, but handover processes fail and emergency call availability is compromised

Engineering Contradiction:

Improveemergency call connectivityVSAvoidaccess class information management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by integrating access class information management into the existing global system information broadcasting infrastructure. The same SystemInformationBroadcast and SystemInformationModificationIndication messages that convey cell restriction status also carry access class information (accessClassBarred, accessClassRestricted). This multi-functional approach allows the system to manage both restriction status and access class information through a single messaging mechanism, avoiding the need for separate dedicated protocols while ensuring emergency call connectivity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If RAN nodes wait for UE-specific messages to detect restriction status changes, then message complexity is minimized, but productivity of network resource utilization decreases

Engineering Contradiction:

Improvenetwork resource utilizationVSAvoidmessaging system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent ensures continuity of useful action by implementing continuous monitoring and immediate broadcasting of cell restriction status changes through global messages. Instead of relying on intermittent UE-specific messages, the system continuously monitors cell restriction status and promptly propagates changes via SystemInformationBroadcast and SystemInformationModificationIndication messages. This continuous action ensures that all RAN nodes maintain up-to-date information, enabling immediate and accurate handover decisions without waiting for UE-specific triggers.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS8165587B2Communicating cell restriction status information between radio access network nodes

Publication Date: 2012.04.24 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A cellular radio communications network includes a core network coupled to a radio access network (RAN) that has multiple RAN nodes for communication with mobile radio terminals. Each of the multiple RAN nodes serves one or more cells. At least one cell associated with a first RAN node is in a restricted or reserved access state in which access to the one cell is restricted for at least some mobile radio terminals. The first RAN node sends a message to a second RAN node to inform the second RAN node of that restricted access cell. The fact that the restricted status of the one cell has changed is detected. A global message tha is not related to a specific mobile terminal is generated that includes information that the restricted status of the one cell has changed. The first RAN node sends the global message to the second RAN node to inform the second RAN node of the change in the restricted status of the one cell.