CSFB RIM Coordination Without Network Support for Faster Call Setup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The delay in establishing a voice call due to cell acquisition on the target cell during Circuit Switch Fall Back (CSFB) in 4G networks when neither the 4G network nor the UE supports VoLTE is significant, as the UE needs to search and capture System Information of the target cell.
Innovation Solution
A method and system that utilizes a coordinating server, such as a HetNet Gateway (HNG), to route Radio Access Network (RAN) Information Management (RIM) messages between a 4G eNodeB and other RAT cells, enabling direct transfer of System Information (SI) without network support, thereby reducing the need for the UE to search for and capture target cell information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE searches and captures System Information of the target cell during CSFB, then the call can be established, but the call setup time increases significantly
Solution Approach 1:
The patent applies preliminary action by having the eNodeB request and pre-fetch the System Information of the target cell before the actual call setup. The eNodeB receives the SI from the target cell in advance, stores it locally, and then provides it to the UE when needed, eliminating the need for the UE to perform time-consuming cell search and SI capture during call establishment.
Solution Approach 2:
The patent uses the eNodeB as an intermediary to transfer System Information from the target cell to the UE. Instead of the UE directly searching for and capturing SI from the target cell, the eNodeB acts as a mediator that has already acquired the SI and can efficiently deliver it to the UE, significantly reducing the call setup time.
2Reliability
If the UE performs cell acquisition on the target cell, then the call can be established, but the complexity of the mobility procedure increases
Solution Approach 1:
The eNodeB performs the complex task of requesting and capturing System Information from the target cell in advance, before the UE needs to establish a call. This preliminary action shifts the complexity from the UE's mobility procedure to the eNodeB's preparation process, simplifying the UE's role during actual call setup.
Solution Approach 2:
The eNodeB serves as an intermediary that handles the complex cell acquisition and System Information capture processes. By centralizing this complexity in the eNodeB rather than requiring the UE to perform it, the mobility procedure becomes simpler for the UE while maintaining reliable call establishment.
Data Source
AI summary
A method and system for for providing Circuit Switch Fall Back (CSFB) with Radio Access Network (RAN) Information Management (RIM) without network support is presented. In one embodiment, a method includes receiving, by a coordinating server, direct information transfer System Information (SI) messages with RIM Packet Data Unit (PDU) from an eNodeB; sending, by the coordinating server, a RAN-information-request message to a relevant cell, using the routing information in the RIM PDU; collecting and replaying by the cell the SI needed for CFSB to the coordinating server; storing, by the coordinating server, the latest SI information per cell; and replaying, by the coordinating server, the eNodeB with the stored SI information using a MME direct information transfer S1 message.