HNB GW Access Control for UTRAN Femtocell Coexistence
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Solution Overview
Problem
Existing femtocell access control systems struggle to simultaneously support legacy UEs that do not support Closed Subscriber Groups (CSGs) and CSG-capable UEs, due to differences in standards between E-UTRAN and UTRAN networks, requiring efficient access control mechanisms to manage diverse UE capabilities.
Innovation Solution
The implementation of a method where the HNB GW defers access control to the CN for CSG-capable UEs, while performing access control for non-CSG capable UEs, using indicators in registration/connection signaling to determine UE capabilities and differentiate handling, ensuring efficient access control processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the HNB GW performs access control for all UEs, then legacy UEs can be supported, but CSG-capable UEs cannot be properly authorized
Solution Approach 1:
The patent segments the access control process into two distinct paths based on UE capability: one path for legacy UEs where the HNB GW performs access control, and another path for CSG-capable UEs where the HNB GW defers to the CN for authorization. This segmentation allows each UE type to be handled according to its specific requirements, resolving the contradiction between supporting legacy UEs and properly authorizing CSG-capable UEs.
Solution Approach 2:
The patent introduces dynamic behavior to the HNB GW, which adapts its access control actions based on the UE's capability indicators. The HNB GW dynamically switches between performing access control locally (for legacy UEs) and deferring to the CN (for CSG-capable UEs), making the system flexible and adaptable to different UE types rather than following a static access control approach.
2Reliability
If the HNB GW defers access control to the CN for all UEs, then CSG-capable UEs can be properly authorized, but access control efficiency decreases
Solution Approach 1:
The patent segments the authorization process by UE capability, directing CSG-capable UEs to the CN for proper CSG ID verification while allowing legacy UEs to be handled efficiently by the HNB GW using existing access control lists. This segmentation ensures reliable authorization for CSG-capable UEs without unnecessarily reducing efficiency for all UEs.
Solution Approach 2:
The patent applies partial deferral to the CN only when necessary (for CSG-capable UEs), rather than deferring all access control decisions. The HNB GW retains access control functionality for legacy UEs, performing access control locally to maintain efficiency, while partially deferring to the CN only for the specific case of CSG-capable UEs requiring CSG ID verification.
3Device complexity
If a unified access control method is used for all UEs, then system complexity is reduced, but compatibility with both legacy and CSG-capable UEs cannot be achieved
Solution Approach 1:
The patent introduces dynamic capability detection and conditional processing logic that allows the HNB GW to automatically adapt its behavior based on UE type indicators. This dynamic approach maintains relatively simple system architecture while achieving high compatibility, as the system automatically selects the appropriate access control method without requiring complex manual configuration or multiple dedicated systems.
Solution Approach 2:
The HNB GW is designed with universal functionality to handle both legacy UEs and CSG-capable UEs through a single access control mechanism that detects UE capability and applies the appropriate authorization method. This multi-functional design eliminates the need for separate access control systems for different UE types, maintaining system simplicity while achieving broad compatibility.
Data Source
AI summary
The teachings herein provide authorization control enabling the co-existence of legacy mobile terminals (20) that do not support Closed Subscriber Groups (CSGs), and non-legacy mobile terminals (20) that do. New behaviors are defined for a CSG femtocell base station (10) (referred to as a Home NodeB or HNB), and for a base station gateway (14) (referred to as a HNB Gateway or HNB GW) that couples the HNB (10) to a Core Network (CN) (22). The HNB (10) and/or the HNB GW (14) determine whether a terminal (20) attempting to gain connection through the HNB (10) supports CSGs. If not, the HNB GW (14) performs access control and rejects the connection attempt if authorization fails. If the terminal (20) is recognized as supporting CSGs, the HNB GW (14) defers access control to the CN (22) by automatically accepting registration/connection requests from the HNB (10) for CSG-capable terminals (20). In such cases, the CN (22) is relied upon for access control, including any CSG authorization of the terminal (20). The HNB GW (14) indicates to the CN (22) whether or not access control was performed for the terminal (20).