IMS Centralized Services Gateway CSFB Signaling Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Circuit Switched Fallback (CSFB) methods in LTE systems require high signaling efforts due to the lack of voice call support, leading to complex procedures and increased overhead in network operations.
Innovation Solution
Implementing an improved CSFB method within an IMS centralized services architecture that reduces signaling requirements by utilizing an IP Multimedia Subsystem (IMS) infrastructure, specifically through the use of an IP Multimedia Subsystem Centralized Services (ICS) Gateway (GW) and Telephony Application Server (TAS), which facilitates voice call handling with reduced signaling via SIP interfaces and CSFB indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional CSFB methods are used in LTE systems, then voice call functionality is achieved, but signaling overhead and network complexity increase significantly
Solution Approach 1:
The patent introduces an IMS centralized services gateway as an intermediary entity that mediates between the LTE packet-switched network and the legacy circuit-switched network. This gateway handles the complex signaling translations and protocol conversions, shielding the LTE core network from CSFB signaling complexity while enabling voice call functionality through the IMS framework
2Adaptability or versatility
If CSFB procedures are implemented to enable voice calls on LTE, then voice service is provided, but network operation overhead increases
Solution Approach 1:
The patent leverages the IMS framework's multi-functionality to handle both voice calls and data services through a unified packet-switched architecture. The IMS centralized services gateway provides universal service handling, allowing the network to manage voice, video, and data services through common signaling paths, thereby reducing overall network operation overhead while maintaining voice service capability
3Reliability
If LTE systems implement CSFB for voice calls, then voice communication is enabled, but service consistency across different access types deteriorates
Solution Approach 1:
The patent merges the circuit-switched voice call handling into the packet-switched IMS framework by combining CSFB procedures with IMS service flow. This integration allows voice calls to be managed through the same IMS signaling paths as other IP-based services, ensuring consistent service delivery across different access types and eliminating the dichotomy between CS and PS service handling
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of performing CSFB in an IMS comprises receiving, at a TAS, an incoming voice call for a UE attached to an EPS; paging the UE by the first ICS GW; receiving, by a second ICS GW associated with a second CS RAN currently connected to the UE, a Location Update message from the UE, the Location Update message containing a first CSFB indicator; transmitting, by the second ICS GW, a Registration message to the TAS, the Registration message containing a second CSFB indicator in response to the first CSFB indicator in the Location Update message; transmitting, by the TAS, a Cancel message to the first ICS GW; and transmitting, by the TAS, an Invite message to the second ICS GW to complete the voice call with the UE.