QoS Flow-to-DRB Mapping Sharing for Reliable 5G Handover
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Solution Overview
Problem
In the 5G communication system, base stations lack the knowledge of QoS flow-to-DRB mapping rules for neighboring base stations, leading to incorrect packet transmission during handovers and offloading due to differing mapping rules between source and target base stations.
Innovation Solution
A method for sharing QoS flow-to-DRB mapping rules between base stations, including procedures for handover, offloading, Xn interface setup, and configuration updates, ensuring consistent mapping rules across neighboring base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If base stations use independent QoS flow-to-DRB mapping rules, then each base station can optimize its own packet routing, but handover and offloading fail when mapping rules differ between source and target base stations
Solution Approach 1:
The source base station transmits its QoS flow-to-DRB mapping rule to the target base station before handover occurs. This preliminary action ensures the target base station has the necessary mapping information in advance, allowing it to correctly route packets without needing to independently determine the mapping rule, thus resolving the reliability issue while preserving independent optimization capability
Solution Approach 2:
The mapping rule transmission acts as an intermediary mechanism between source and target base stations. Instead of requiring the target base station to independently discover or infer the mapping rule, the rule is directly transmitted from the source, serving as a mediator that ensures consistent mapping behavior across handover boundaries
2Reliability
If base stations share QoS flow-to-DRB mapping rules, then handover and offloading reliability improves, but base stations must exchange additional information increasing system complexity
Solution Approach 1:
The patent extracts only the essential mapping rule information needed for handover, rather than exchanging complete base station configuration data. By taking out and transmitting only the specific QoS flow-to-DRB mapping rule parameter, the solution improves reliability while minimizing the increase in system complexity
Solution Approach 2:
The mapping rule is transmitted in advance through existing handover signaling procedures, rather than establishing new complex information exchange mechanisms. This preliminary transmission of necessary information leverages existing system structures, reducing the overall complexity increase
3Measurement precision
If base stations transmit mapping rules during handover, then packet forwarding accuracy improves, but handover signaling overhead increases
Solution Approach 1:
The mapping rule transmission is integrated into existing handover signaling messages, allowing these messages to serve multiple functions: both coordinating the handover process and conveying the mapping rule information. This multi-functionality improves packet routing accuracy without proportionally increasing signaling overhead
Solution Approach 2:
The patent merges the mapping rule transmission with the handover request and response signaling. By combining these information exchanges into a single integrated process rather than separate transmissions, the solution achieves accurate packet forwarding while minimizing the total signaling overhead
Data Source
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AI summary
Provided are a method in which a source base station (BS) transmits a Quality of Service (QoS) flow-to-data radio bearer (DRB) mapping rule to a target BS in a wireless communication system, and a device supporting the same. The method may include: receiving, from a user equipment (UE), a measurement result of a target cell; determining the handover of the UE to the target BS on the basis of the measurement result; and transmitting, to the target BS, a handover request message including a QoS flow-to-DRB mapping rule of the source BS.