Inter-RAT Handover Access Control for Closed Subscriber RANs
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Solution Overview
Problem
Existing wireless networks face challenges in performing inter-radio access technology (inter-RAT) handovers between networks with different access policies, particularly when the source network lacks information about the target network's access policies, leading to difficulties in determining whether to allow or deny handovers for UEs.
Innovation Solution
A system where provisioning system maintains access policies and identifiers for base stations, allowing target base stations to determine handover authorization based on their own policies, without requiring core network modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target LTE RAN enforces access policies to restrict usage to certain UEs, then network security is improved, but handover complexity increases because access policy information is not readily available in the source RAN
Solution Approach 1:
The patent applies preliminary action by having the source RAN provide access policy information to the EPC before the handover is executed. The EPC stores this information and uses it during the handover decision-making process, allowing the target RAN to enforce access policies without encountering complexity during the actual handover execution.
Solution Approach 2:
The EPC acts as an intermediary between the source RAN and target RAN. It receives access policy information from the source RAN, stores it, and provides it to the target RAN during handover, thereby mediating the information flow and reducing handover complexity while maintaining security enforcement.
2Productivity
If access policy information is provided from source RAN to EPC to enable handover decisions, then handover efficiency is improved, but information management complexity increases
Solution Approach 1:
The patent extracts access policy information from the source RAN and transfers it to the EPC, which then manages this information separately. This extraction allows the handover process to proceed efficiently using pre-available information, while the EPC handles the information management complexity in a centralized manner rather than distributing it across multiple RANs.
3Reliability
If the target LTE RAN determines handover authorization independently, then network security is improved, but handover speed decreases due to additional verification steps
Solution Approach 1:
The patent applies preliminary action by having the EPC determine handover authorization in advance using access policy information provided from the source RAN. This pre-determination of authorization eliminates the need for additional verification steps at the target RAN during handover execution, thereby maintaining security while improving handover speed.
Data Source
AI summary
A system described herein may receive a request for a User Equipment (“UE”) to access a radio access network (“RAN”), which may implement a Closed Subscriber Group (“CSG”) technique. The request may be a handover request from a different RAN, which may implement a different radio access technology (“RAT”). The system may determine that an access policy for the particular RAN does not indicate that the UE is authorized to access the RAN. The system may output a request to the RAN, including an indication that the access policy for the RAN does not indicate that the UE is authorized to access the RAN. The system may receive a response to the second request. The response may include an indication of whether the UE is allowed to access the RAN, as determined by the RAN based on one or more conditions in addition to an identifier of the UE.