Home eNodeB Access Control for Seamless CSG Handover
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Solution Overview
Problem
In mobile communication systems, particularly in 3GPP LTE/SAE networks, there is a challenge in efficiently managing handovers between Closed Subscriber Groups (CSGs) to minimize wireless resource waste and ensure service continuity when a terminal's access permission expires or is revoked, especially in Home(e)NodeB systems where concrete methods for status consideration and resource optimization are lacking.
Innovation Solution
A method is introduced to control terminal access by determining if the access timer has expired, comparing the terminal's allowed CSG list with the Home(e)NodeB's CSG ID list, and changing the CSG ID to another accessible ID if available, thereby maintaining service continuity while minimizing signaling exchange and resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal's access permission to a Home(e)NodeB expires or is revoked, then the terminal should be denied access to maintain security and resource management, but this causes service interruption and requires handover to other cells which wastes wireless resources
Solution Approach 1:
The Home(e)NodeB proactively checks whether the terminal can access other CSGs before denying access due to expired or revoked permission. The network performs preliminary evaluation of alternative CSGs and prepares handover parameters in advance, enabling seamless transition without forcing the terminal to search for alternative cells independently, thus reducing wireless resource waste.
Solution Approach 2:
The Home(e)NodeB acts as an intermediary between the terminal and the core network, providing CSG ID list information to assist the terminal in selecting alternative CSGs. This intermediary role allows the network to manage access control while guiding the terminal to appropriate alternative cells, reducing unnecessary handovers and resource waste.
2Reliability
If the terminal performs handover to other cells when access permission expires, then service continuity can be maintained, but this increases signaling exchange and network complexity
Solution Approach 1:
The Home(e)NodeB performs preliminary action by checking alternative CSG accessibility and preparing handover parameters before the terminal actually needs to handover. This advance preparation reduces the signaling exchange during the actual handover process, as the network already has the necessary information and parameters ready.
Solution Approach 2:
The Home(e)NodeB provides feedback to the terminal in the form of CSG ID list information, enabling the terminal to make informed decisions about alternative CSGs. This feedback mechanism simplifies the handover process by providing the terminal with pre-processed network information, reducing the need for complex signaling exchanges.
3Measurement precision
If the Home(e)NodeB provides detailed access control information to the terminal, then access management precision is improved, but this increases the burden on the terminal and network processing
Solution Approach 1:
The Home(e)NodeB extracts only the necessary access control information (CSG ID list) and provides it to the terminal in a condensed format. This extraction approach maintains access control precision by providing sufficient information for the terminal to make appropriate decisions, while reducing the overall information processing burden on both the terminal and network.
Data Source
AI summary
A method for controlling access of a terminal, which is connected to a Home (e)NodeB operated in a closed access mode, the method comprises: determining whether a timer, which designates allowable time to access to the Home (e)NodeB by using a specific closed subscriber group (CSG) ID, has expired; comparing an allowed CSG list for the terminal with a CSG ID list of the Home (e)NodeB if the allowed access timer has expired; and changing the specific CSG ID of the terminal into another CSG ID such that service to the terminal from the Home (e)NodeB is maintained if there is the another CSG ID in both the allowed CSG ID list for the terminal and the CSG ID list of the Home (e)NodeB.