UE Forbidden CSG List Management for Wireless Access Control
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Solution Overview
Problem
In wireless communication systems, access control issues arise due to lack of synchronization between user equipment (UE) and the network, particularly when a UE is removed from a Closed Subscriber Group (CSG) but the operator CSG list is not updated, leading to authorization rejections and inability to modify the list due to its read-only nature.
Innovation Solution
A method where the UE stores forbidden CSG IDs after receiving authorization rejections, preventing access to unsynchronized CSG cells and allowing for future updates to the operator CSG list, thereby avoiding unauthorized access and enabling manual CSG selection mode management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operator CSG list is maintained as read-only and operator-controlled, then network security and centralized control are improved, but the UE cannot update the list locally when desynchronized, leading to repeated authorization failures
Solution Approach 1:
The patent divides the CSG list management into two separate lists: the operator CSG list (read-only, network-controlled) and the forbidden CSG list (UE-managed). This segmentation allows the UE to independently track and avoid forbidden CSGs without compromising the security and centralized control of the operator CSG list.
Solution Approach 2:
The forbidden CSG list acts as an intermediary mechanism between the operator CSG list and the UE's access attempts. When the UE receives a reject message, it adds the CSG ID to the forbidden list, which then mediates future access decisions by preventing attempts to access forbidden CSGs, thus resolving the synchronization issue without modifying the read-only operator list.
2Adaptability or versatility
If the UE attempts to access a CSG cell using an outdated operator CSG list, then the UE can initiate access attempts, but it receives repeated authorization rejections and cannot remove outdated CSG entries
Solution Approach 1:
The system implements feedback through reject messages from the network to the UE. When the UE attempts to access a CSG cell and receives a reject message indicating lack of authorization, this feedback triggers the UE to add the CSG ID to its forbidden CSG list, thereby learning from the failure and avoiding repeated attempts to the same forbidden CSG.
Solution Approach 2:
The patent converts the harmful effect of repeated authorization failures into a beneficial outcome by using the reject messages to automatically populate the forbidden CSG list. The failures provide information that enables the UE to improve its access behavior, transforming negative experiences into positive synchronization without needing to modify the operator CSG list.
3Speed
If the UE stores and uses the operator CSG list locally, then access decisions can be made quickly, but synchronization issues arise when the network updates CSG memberships without notifying the UE
Solution Approach 1:
The UE performs preliminary actions by maintaining a forbidden CSG list that proactively blocks access to known unauthorized CSGs. This preliminary filtering occurs before actual access attempts, preventing wasted time on doomed attempts and maintaining speed while gradually improving synchronization through accumulated forbidden CSG information.
Data Source
AI summary
Systems and methodologies are described that facilitate managing access control to Closed Subscriber Groups (CSGs) in a wireless communication environment. A user equipment (UE) can store an operator CSG list, which can be read only and controlled by an operator. Further, the operator CSG list can lack synchronization to a CSG subscription for the UE retained in the network. Thus, upon selecting to access a CSG cell associated with a CSG with a corresponding CSG Identifier (ID) included in the operator CSG list of the UE, a reject message that indicates that the UE lacks authorization for the CSG can be received. Moreover, the CSG ID can be stored as a forbidden CSG ID of the UE in a set of forbidden CSG IDs in response to receipt of the reject message when the CSG ID is included in the operator CSG list.