5G NR Uplink Packet Dropping via HARQ Failure Feedback
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Solution Overview
Problem
In 5G new radio (NR) networks, if a critical packet of a packet data unit (PDU) set is not successfully delivered, the remaining packets in the set become useless, necessitating proactive uplink packet dropping to avoid unnecessary transmission.
Innovation Solution
Implementing a hybrid automatic repeat request (HARQ) mechanism with a NACK counter to track implicit and explicit acknowledgments, and using new MAC CEs to manage packet dropping based on configured thresholds and timers, allowing the UE to proactively drop packets when delivery failure is imminent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the UE continues to transmit all packets in a PDU set, then the quantity of transmitted packets increases, but the loss of time and energy increases when packets are ultimately useless
Solution Approach 1:
The UE performs preliminary actions by monitoring HARQ feedback and proactively determining packet delivery status before the PDB expires. When a critical packet delivery failure is detected, the UE preemptively drops associated packets in the same PDU set or different PDU sets, avoiding the time waste of transmitting packets that will not be useful to the receiving entity.
2Productivity
If the UE transmits all packets in a PDU set, then the productivity increases, but the loss of energy increases for transmitting useless packets
Solution Approach 1:
The UE utilizes HARQ feedback mechanisms to monitor the delivery status of critical packets. Based on this feedback, the UE makes informed decisions about dropping subsequent packets in the same PDU set or different PDU sets, thereby eliminating energy waste on transmissions that would not contribute to productive communication.
3Loss of time
If the UE implements proactive packet dropping, then the loss of time decreases by avoiding useless transmissions, but the device complexity increases due to HARQ monitoring and packet association tracking
Solution Approach 1:
The UE autonomously monitors its own packet transmission status through HARQ feedback and self-determines which packets should be dropped based on pre-configured PDU set associations. This self-service approach enables the UE to reduce time loss from useless transmissions while managing the complexity through automated decision-making rather than external control.
4Reliability
If the UE drops packets based on critical packet failure, then the reliability of resource utilization improves, but the measurement precision required for packet delivery status detection increases
Solution Approach 1:
The network configures the UE with specific parameters including PDU set associations, packet delay budgets, and thresholds for critical packet determination. By changing and optimizing these parameters, the system achieves reliable resource utilization while managing the measurement precision requirements through configurable thresholds and timing parameters rather than requiring perfect detection accuracy.
Data Source
AI summary
A user equipment (UE) is configured to identify an indication in response to uplink data, the indication indicating that a first packet was not successfully delivered to a receiving entity, determine that one or more packets associated with the first packet are to be dropped by the UE based on at least the indication, wherein the first packet and the one or more packets associated with the first packet are part of a same packet data unit (PDU) set or a different PDU set and drop the one or more packets associated with the first packet.