Indirect SRVCC Handover via LTE Mediator for 5G Voice Continuity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current 5G wireless communication systems lack a direct interface with 2G or 3G systems, leading to inefficient two-step fallback procedures when a user equipment (UE) moves out of 5G coverage, resulting in poor user experience due to indirect handovers via LTE systems.
Innovation Solution
Implementing an indirect Single Radio Voice Call Continuity (SRVCC) method that allows a UE to perform a bypass handover from a 5G system directly to a 2G or 3G system using an LTE system as an intermediary, by configuring the UE to measure neighboring 2G or 3G base stations and initiating a handover procedure through an Access and Mobility Management Function (AMF) and Mobility Management Entity (MME) to transfer the voice call.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a two-step fallback procedure is used from 5G to 2G/3G via LTE, then voice service can be maintained, but handover efficiency deteriorates and user experience worsens
Solution Approach 1:
The patent introduces the LTE system as an intermediary network device that mediates between the 5G system and the 2G/3G system. The AMF in the 5G system communicates with the MME in the LTE system, which then communicates with the MSC server in the 2G/3G system. This intermediary approach enables indirect SRVCC handover, allowing the UE to transition from 5G to 2G/3G voice services without requiring a direct interface, thereby improving handover efficiency and reducing time loss compared to traditional two-step fallback procedures.
2Device complexity
If no direct interface exists between 5G and 2G/3G systems, then system complexity is reduced, but handover capability deteriorates
Solution Approach 1:
The patent utilizes the LTE system as an intermediary to enable handover capability between 5G and 2G/3G systems without requiring a direct interface. The MME in the LTE system acts as a mediator that receives handover requests from the 5G system's AMF and forwards them to the 2G/3G system's MSC server. This approach maintains low system interface complexity while restoring full handover capability through the indirect SRVCC procedure.
Solution Approach 2:
The patent leverages the universal compatibility of the LTE system, which can interface with both 5G systems (via AMF) and 2G/3G systems (via MSC server). The LTE network's MME performs multiple functions: receiving handover requests from 5G, selecting appropriate target 2G/3G base stations, and coordinating the actual handover execution. This multi-functionality enables the LTE system to serve as a universal bridge, maintaining adaptability across different network generations without increasing overall system complexity.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. An access and mobility management function (AMF) associated with a first radio access network (RAN) may identify a user equipment (UE) connected to a source base station of the first RAN. The AMF may receive a handover message including a voice call continuity handover trigger message indicating a handover of the UE to a target base station associated with a second RAN. In some examples, the AMF may transmit a bypass handover message to a second network device based a on the received handover message. In some cases, the bypass handover message may include the voice call continuity handover trigger message. In some examples, the second network device is a mobility management entity (MME) associated with an Evolved Universal Terrestrial Radio Access Network (E-UTRAN).