Parallel Downlink Transmission for Lower-Latency Wireless Handover
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Solution Overview
Problem
Mobile communication systems experience service disruptions and delays during handover procedures due to the need for path switch operations and data buffering at target base stations, which can take up to 20-30 milliseconds.
Innovation Solution
Simultaneously transmitting downlink data to both the source and target base stations during handover, enforcing mapping rules between Protocol Data Unit (PDU) sessions, Quality of Service (QoS) flows, and Data Radio Bearers (DRBs) to eliminate the need for data forwarding and path switch operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If downlink data is transmitted only to the source base station during handover, then data transmission simplicity is maintained, but service disruption and delay increase (20-30 milliseconds)
Solution Approach 1:
The patent applies preliminary action by transmitting downlink data to both the source base station and the target base station simultaneously before the handover is completed. This allows the target base station to have data ready in advance, eliminating the 20-30 millisecond delay that would otherwise occur when data is forwarded after handover. The mapping relationship between PDU sessions, QoS flows, and DRBs is established beforehand to enable this parallel transmission approach.
2Reliability
If data buffering is performed at the target base station, then data continuity is ensured, but service disruption time increases
Solution Approach 1:
The patent implements continuity of useful action by maintaining parallel data transmission paths to both source and target base stations during handover. This ensures that data flow continues uninterrupted to the UE regardless of which base station is serving it, eliminating service disruption while maintaining data continuity. The simultaneous transmission approach keeps the data delivery process continuously active without interruption.
3Reliability
If path switch operations are performed during handover, then network routing is updated, but handover delay increases
Solution Approach 1:
The patent applies preliminary action by establishing the mapping relationship between PDU sessions, QoS flows, and DRBs before handover occurs. This pre-configuration allows the target base station to be ready to receive and process data immediately upon handover completion, eliminating the need for time-consuming path switch operations during the handover process itself.
Data Source
AI summary
Methods, apparatus, and systems for wireless communication are described. In one example aspect, a method includes performing, by a communication node, a handover procedure from a source base station to a target base station based on information associated with a Protocol Data Unit (PDU) session. The information indicates that at least one tunnel in a list of tunnels that carry user data has a one-to-one correspondence with a Quality of Service (QoS) flow. The method also includes transmitting, for the handover procedure, downlink data to both the source base station and the target base station by the communication node.