RAN Interface Handover Signalling for LTE-NR Interworking
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Solution Overview
Problem
Current mobile telecommunications systems face challenges in efficiently managing handovers between network nodes, particularly in new radio access technology (NR) systems, due to high control signalling overhead and increased chances of handover failure, especially in small cells and fast-moving devices.
Innovation Solution
The proposed solution involves a wireless telecommunications system that facilitates handovers by forming an interworking arrangement between LTE and NR networks, where information necessary for completing handovers is exchanged directly between infrastructure equipment using a RAN interface associated with the second RAT, reducing reliance on core network signalling and minimizing data packet loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover procedures are managed through core network signalling in current mobile telecommunications systems, then handover can be completed with established protocols, but control signalling overhead increases and handover failure chances increase
Solution Approach 1:
The patent extracts the handover signalling process from the core network domain and relocates it to the RAN (Radio Access Network) domain. By implementing handover procedures directly between gNBs (next generation base stations) using RAN interface signalling, the solution removes the need for core network involvement in handover signalling, thereby reducing control signalling overhead while maintaining handover reliability
Solution Approach 2:
The patent introduces the RAN interface as an intermediary channel for handover signalling between infrastructure equipment. This intermediary mechanism enables direct communication between source and target gNBs for handover purposes, bypassing the core network and reducing signalling overhead while ensuring reliable handover execution
2Reliability
If handover procedures involve extensive core network signalling, then protocol standards can be followed, but data packet loss increases during handover
Solution Approach 1:
The patent implements preliminary data forwarding from the source gNB to the target gNB before the actual handover execution. By pre-positioning data packets at the target infrastructure equipment, the system ensures continuous data flow during handover, preventing packet loss while maintaining reliable connectivity throughout the transition
3Adaptability or versatility
If traditional handover procedures are used in new RAT networks, then existing protocols can be applied, but support for diverse device requirements becomes insufficient
Solution Approach 1:
The patent introduces dynamic handover parameters and flexible mobility management mechanisms that can be adapted to different device types and service requirements. By enabling dynamic adjustment of handover thresholds, timing, and data forwarding parameters, the system can optimize performance for diverse devices ranging from low-complexity IoT devices to high-performance smartphones, thereby improving adaptability without significantly increasing complexity
Data Source
AI summary
A wireless telecommunications system including a terminal device; first infrastructure equipment operable to communicate with the terminal device using a first radio access technology (RAT) and second infrastructure equipment operable to communicate with the terminal device using a second RAT. During a handover procedure for handover from the first infrastructure equipment as a source master infrastructure equipment to a third infrastructure equipment as a target master infrastructure equipment, the second infrastructure equipment is operable to communicate with the third infrastructure equipment using an interface associated with the second RAT so as to allow information necessary for completing the handover to be exchanged between the first infrastructure equipment and the third infrastructure equipment via the second infrastructure equipment.