QoS Flow Reordering Timer for Lossless Packet Delivery
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Solution Overview
Problem
In wireless communication systems, particularly in LTE and 5G networks, the change in QoS flow to DRB mapping leads to packet loss and out-of-sequence delivery issues, as existing technologies fail to ensure in-sequence delivery and lossless data transmission during handovers.
Innovation Solution
A method and apparatus for User Equipment (UE) that implements a reordering timer mechanism to delay and reorder packets when QoS flow mapping changes from an old DRB to a new DRB, ensuring lossless and in-sequence delivery by temporarily buffering packets from the old DRB and delivering them only after a configured time has elapsed, thereby maintaining data integrity during network handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If QoS flow to DRB mapping is changed during handover, then network flexibility and adaptability are improved, but packet loss and out-of-sequence delivery occur
Solution Approach 1:
The patent applies preliminary action by configuring a reordering timer before the actual handover completes. The timer is set to a value greater than the handover execution time, ensuring that packets are buffered in advance and delivered in the correct sequence after handover, preventing out-of-sequence delivery and packet loss while maintaining mapping flexibility
Solution Approach 2:
The patent introduces a reordering timer as an intermediary mechanism between the QoS flow mapping change and packet delivery. This timer acts as a mediator that temporarily holds packets during the mapping transition, ensuring reliable in-sequence delivery while allowing the network to perform flexible remapping operations
2Reliability
If packets are buffered during reordering, then in-sequence delivery is ensured, but transmission delay increases
Solution Approach 1:
The reordering timer is configured in advance with a value that exceeds the handover execution time. This preliminary configuration allows the system to prepare for handover without actual packet buffering during the transition, minimizing transmission delay while ensuring in-sequence delivery through pre-planned timer-based reordering
3Reliability
If reordering timer is configured, then packet loss is prevented, but device complexity increases
Solution Approach 1:
The reordering mechanism operates autonomously through the configured timer without requiring complex external control or intervention. The timer automatically manages packet buffering and release based on the pre-configured value, preventing packet loss through a self-service mechanism that minimizes device complexity
Data Source
Figure 1~2A
Figure 2B
Figure 3(a)~3(b)
AI summary
The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for transmitting lossless data packet based on QoS framework in wireless communication system, the method comprising: starting a timer for a first QoS flow when a DRB which is mapped to the first QoS flow is changed from a first DRB to a second DRB; delivering packets of the first QoS flow received from the first DRB to an upper layer while the timer is running; when the timer expires, starting to deliver the packets of the first QoS flow received from the second DRB while stopping the delivering packets of the first QoS flow received from the first DRB.