Local CSG Server Access Control for Roaming UEs
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Solution Overview
Problem
In the context of 4G mobile communication systems, there is a lack of technology to efficiently manage user equipment (UE) access to Home (e)Node B in visited networks, particularly when operating in closed or hybrid access modes, due to the absence of CSG subscriber information from the home network, leading to increased overhead for macro base stations and potential service disruptions.
Innovation Solution
A method is proposed where the UE receives local and home network CSG-related information, which is then used to construct attach or Tracking Area Update (TAU) requests, allowing access control based on predefined priority settings, ensuring proper CSG service provision even in visited networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE roams to a visited network and the Home (e)Node B operates in closed or hybrid access mode, then CSG service can be provided to roaming UEs, but the macro base station overhead increases due to lack of CSG subscriber information from home network
Solution Approach 1:
The patent introduces a local CSG server in the visited network that acts as an intermediary to provide CSG subscriber information to the MME. This mediator enables the visited network to make access control decisions without requiring continuous information transfer from the home network, thereby reducing macro base station overhead while maintaining reliable CSG service provision.
Solution Approach 2:
The local CSG server pre-stores CSG subscriber information and makes it available to the MME before the UE attaches to the Home (e)Node B. This preliminary action eliminates the need for real-time information requests during access control, reducing processing overhead at the macro base station while ensuring reliable service provision.
2Adaptability or versatility
If CSG-related information is obtained from both home network and visited network, then comprehensive access control is possible, but conflicts may arise between the two sources of information
Solution Approach 1:
The patent changes the parameter of information source priority by establishing that visited network CSG information takes precedence over home network CSG information for access control decisions. This parameter change resolves conflicts between the two information sources by clearly defining which source is authoritative, thereby maintaining both comprehensive access control capability and information consistency.
Solution Approach 2:
The system implements a feedback mechanism where the MME uses CSG information from both home and visited networks, applies conflict resolution based on predefined priority rules, and makes access control decisions. This feedback loop ensures that the system adapts to the presence of multiple information sources while maintaining reliable and consistent access control.
3Ease of operation
If macro base stations manually manage CSG access for roaming UEs, then access control can be implemented, but unnecessary handover procedures occur
Solution Approach 1:
The patent enables the network to automatically manage CSG access control by having the MME autonomously make access decisions based on CSG subscriber information from the local CSG server. This self-service approach eliminates the need for manual management and prevents unnecessary handovers by proactively blocking non-CSG UEs before they can attach, thereby saving time while maintaining ease of operation.
Solution Approach 2:
The system performs preliminary access control decisions by checking CSG subscriber information before the UE attempts to attach to the Home (e)Node B. This preliminary action prevents unnecessary handover procedures by identifying and blocking non-CSG UEs in advance, rather than allowing them to attach and then requiring manual intervention or forced handovers.
4Device complexity
If CSG subscriber information is not available from home network, then access control can be simplified, but service disruption may occur for roaming UEs
Solution Approach 1:
The local CSG server in the visited network serves as an intermediary that provides CSG subscriber information to the MME, enabling access control decisions without requiring direct information transfer from the home network. This mediator ensures service availability for roaming UEs while simplifying the information management architecture by localizing the data storage and processing function.
Solution Approach 2:
The patent applies local quality by storing and processing CSG subscriber information locally at the visited network's local CSG server rather than relying on remote home network data. This local quality approach ensures service availability for roaming UEs by having the information readily accessible at the point of access, while simplifying the overall information management system.
Data Source
AI summary
A method of controlling an access, which is controlled by a Mobility Management Entity (MME) of a control plane in a visited network; and the MME therefore are discussed. The method according to one embodiment includes receiving an access request message or an update request message requested by a roaming user equipment (UE) from a Home (e)Node B; and determining Closed Subscriber Group (CSG) information among first CSG information and second CSG information based on predefined priority information when the first CSG information conflicts with the second CSG information. The predefined priority information indicates that the first CSG information takes precedence over the second CSG information. The method further includes transmitting an accept message based on the determined CSG information via the Home (e)Node B. The first CSG information is CSG-related information defined in a home network and the second CSG information is CSG-related information in the visited network.