PCRF Selection via HSS Integration for Latency Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for accessing a Policy Control and Charging Rules Function (PCRF) in 3GPP networks introduce additional latency and transport connection scaling issues during IP-CAN session establishment, modification, and termination, requiring deployment of additional Diameter Routing Agent (DRA) elements and message forwarding.
Innovation Solution
Integrate the PCRF Selection Function within existing elements, such as the Home Subscriber Server (HSS) or 3GPP AAA server, sharing a common state store for User-Equipment-to-PCRF binding, utilizing existing signaling connections to avoid additional latency and scaling issues, and communicate the selected PCRF through established interfaces like S6a, S8, S6b, or SGi.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redirect DRA or proxy DRA is deployed to access PCRF, then PCRF selection functionality is provided, but additional latency is introduced during IP-CAN session establishment and termination
Solution Approach 1:
The patent combines the DRA and PCRF Selection Function into a single integrated element. The DRA maintains information about user identity, APN, user equipment IP addresses, and the selected PCRF in a unified database, eliminating the need for separate PCRF selection functionality and reducing latency by removing additional lookup steps.
Solution Approach 2:
The DRA pre-selects and stores the appropriate PCRF address in its database before actual PCRF access is needed. When session establishment or modification requests arrive, the DRA can immediately retrieve the pre-determined PCRF address without performing real-time selection, thereby reducing latency.
2Reliability
If a proxy DRA is deployed to forward messages to PCRF, then message routing is provided, but additional latency is introduced to session modification exchanges
Solution Approach 1:
The patent integrates message routing and PCRF selection functions within the same DRA element that maintains the UE-to-PCRF binding database. This unified approach allows the DRA to directly route messages to the correct PCRF using pre-stored binding information, eliminating the additional forwarding latency that would occur with separate proxy elements.
3Reliability
If additional DRA elements are deployed for PCRF access, then PCRF selection capability is enhanced, but transport connection scaling issues arise
Solution Approach 1:
The patent merges the PCRF selection function with the existing DRA infrastructure rather than deploying separate elements. The DRA's existing database capabilities are extended to store UE-to-PCRF bindings, and its existing message handling capabilities are utilized for PCRF access, thereby enhancing functionality without increasing network element complexity or deployment burden.
Solution Approach 2:
The DRA is designed to perform multiple functions: maintaining user session information, selecting appropriate PCRFs based on UE identity and APN, and routing messages to the selected PCRF. This multi-functional approach eliminates the need for dedicated PCRF selection elements and reduces overall network complexity.
Data Source
AI summary
The PCRF Selection Function selects the PCRF for an IP-CAN session. In embodiments, the PCRF Selection Function is located in the HSS and/or the 3GPP AAA server. The PCRF Selection Function is only required to be located in the HSS if a Bearer Binding and Event Reporting Function (BBERF) is deployed in the serving gateway. In this case, the PCRF selection takes place at the time that the PDN Gateway is selected and returned by the HSS to the serving gateway over the HSS to MME interface (S6a).