Low-Latency Handover via Direct Core Network Tunnel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional mobile communication systems face challenges in satisfying ultra-reliability and low-latency (URLLC) requirements due to significant latency and jitter caused by non-ideal backhaul transmission delays during handover procedures in LTE or NR systems.
Innovation Solution
The proposed method involves a terminal and base stations managing packet data convergence protocol (PDCP) downlink and uplink reception status information to configure separate tunnels for data transmission, allowing direct forwarding of data from the core network to the target base station, enabling the terminal to discard and reorder redundant data units, thereby minimizing delay and jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is forwarded through the forwarding tunnel configured based on the inter-base station interface, then the handover procedure can be completed, but a latency or jitter may become so large that it cannot be ignored, and thus ultra-reliability and low-latency (URLLC) requirements cannot be satisfied
Solution Approach 1:
The patent extracts the data forwarding function from the inter-base station interface path and creates a separate direct tunnel from the core network to the target base station. This removes the problematic intermediate forwarding path that causes latency and jitter, allowing URLLC data to bypass the slow inter-base station interface while maintaining standard handover procedures.
Solution Approach 2:
The patent segments the data transmission path into two separate channels: a standard path through the inter-base station interface for regular data, and a dedicated direct tunnel from the core network to the target base station for URLLC data. This segmentation allows different data types to use optimized paths, resolving the contradiction between maintaining handover functionality and achieving low latency.
2Productivity
If a forwarding tunnel is configured between source base station and target base station for data transmission, then data can be forwarded during handover, but the non-ideal backhaul causes transmission delay that cannot be neglected
Solution Approach 1:
The patent introduces a new intermediary element - a direct tunnel connection from the core network to the target base station - that mediates URLLC data transmission. This bypasses the slow inter-base station interface intermediary, providing a faster path for time-sensitive data while preserving the original forwarding tunnel for other data types.
3Stability of the object's composition
If the source base station forwards downlink data to the target base station through the configured forwarding tunnel, then data continuity is maintained during handover, but the transmission delay time is not negligibly small
Solution Approach 1:
The patent establishes the direct tunnel from the core network to the target base station in advance, before the handover is needed for URLLC data. This preliminary setup ensures that when handover occurs, the low-latency path is already ready, maintaining data continuity without the transmission delays that would occur if the path were established after handover initiation.
Data Source
AI summary
An operation method of a terminal performing handover in a mobile communication system may comprise transmitting packet data convergence protocol (PDCP) downlink reception status information of the terminal and information on a target base station to a source base station; receiving downlink data from a user plane function (UPF) via the source base station based on a first tunnel configured between the source base station and the UPF; receiving downlink data from the UPF via the target base station based on a second tunnel configured by the UPF between the target base station and the UPF by using the PDCP downlink reception status information and the information on the target base station, which are transferred from the source base station; and discarding duplicated-received protocol data units (PDUs) from the source base station and the target base station, and reordering remaining PDUs.