Inter-system Handover Data Forwarding in LTE to 5G Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge lies in ensuring data forwarding continuity during handovers between LTE and 5G systems, particularly in allocating EPS bearers and transferring PDU sessions between these systems, as the data bearer modes and architectures differ significantly, leading to uncertainties in how to support seamless service continuity.
Innovation Solution
A method involving base stations acquiring EPS bearer information through intra-system handovers, transmitting handover messages to Access and Mobility Function entities, and receiving data forwarding tunnel information to perform seamless data forwarding between the two systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data forwarding is performed during handover between LTE and 5G systems, then service continuity is improved, but data loss and forwarding delays occur due to architectural differences
Solution Approach 1:
The patent applies preliminary action by establishing data forwarding tunnels and allocating EPS bearer information before the handover is actually executed. The source base station prepares the forwarding path in advance, and the target base station pre-configures the tunnel endpoints, so that when handover occurs, data can be forwarded immediately without waiting for post-handover configuration, thus reducing forwarding delays while ensuring service continuity
2Reliability
If EPS bearer information is acquired through intra-system handover process, then data forwarding continuity is improved, but complexity increases due to mapping between PDU sessions and EPS bearers
Solution Approach 1:
The patent uses the AMF (Access and Mobility Management Function) as an intermediary to manage the complex mapping between PDU sessions and EPS bearers. The AMF receives handover requests from the source base station, performs the PDU session to EPS bearer mapping, and returns the mapped EPS bearer information to the target base station. This intermediary approach centralizes the complexity in the core network rather than distributing it across multiple base stations, simplifying the overall system architecture while ensuring data forwarding continuity
3Reliability
If data forwarding tunnels are established between different systems, then service continuity is maintained, but uncertainty arises from different data bearer modes in LTE and 5G
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the data bearer parameters during handover. The system changes from 5G's PDU session-based architecture to LTE's EPS bearer-based architecture by modifying the tunnel endpoint identifiers, protocol headers, and bearer parameters. The AMF transforms the data flow parameters to be compatible with the target system's bearer mode, enabling seamless transition between different system architectures while maintaining service continuity
Data Source
AI summary
The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services.The present invention provides a method of a base station for supporting an inter-system handover from an evolved packet system (EPS) system to a 5th generation (5G) system. The method comprises receiving, from an access and mobility management function (AMF), a handover request message including E-UTRAN radio access bearer (E-RAB) information and quality of service (Qos) flow information, identifying whether a protocol data unit (PDU) session is accepted or not, determining whether a data forwarding for at least one Qos flow associated with the PDU session is accepted or not based on the E-RAB information and the Qos flow information in case that the PDU session is accepted and transmitting, to the AMF, a handover request acknowledgement message including information on the at least one Qos flow based on the determination. The method solves the data forwarding problem during the movement of a UE between an LTE system and a 5G system, so that the loss of data is avoided and the continuity of services is ensured.