PDCP Discard Timer Selection for Low-Latency Uplink Handover
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies due to static discard timer durations set by network entities, which lack access to UE characteristics, leading to increased latency and decreased efficiency, especially during handover operations.
Innovation Solution
User equipment (UE) performs discard timer selection using a machine learning model based on network entity-specified configuration parameters, allowing dynamic configuration of discard timers for PDCP SDUs, and releases SDUs upon timer expiration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If network entities set static discard timer durations, then configuration simplicity is maintained, but latency increases and system efficiency decreases
Solution Approach 1:
The patent transforms the static discard timer configuration into a dynamic selection mechanism. The UE now performs discard timer selection based on multiple parameters including buffer utilization threshold, QoS values, logical channels, component carriers, and cell groups. This dynamic approach allows the system to adapt timer durations to current network conditions and UE characteristics, reducing latency while maintaining manageable complexity through automated selection procedures.
Solution Approach 2:
The invention changes the discard timer from a fixed parameter to a selectable parameter with multiple possible values. The network entity provides a set of candidate discard timer values, and the UE selects the appropriate value based on current conditions. This parameter change enables the system to optimize latency performance by selecting shorter timers when appropriate while maintaining the ability to use longer timers when needed.
2Device complexity
If network entities set static discard timer durations, then system simplicity is maintained, but system efficiency decreases
Solution Approach 1:
The patent implements self-service by enabling the UE to autonomously perform discard timer selection. Instead of requiring the network entity to continuously adjust timer values based on UE characteristics, the UE uses its own capabilities and received parameters to make the selection. This self-service approach improves system efficiency by enabling faster, more context-aware timer configuration while maintaining system simplicity through standardized procedures.
Solution Approach 2:
The network entity performs preliminary action by providing a configured set of candidate discard timer values and selection parameters to the UE before actual data transmission begins. This preliminary configuration enables the UE to quickly select an appropriate timer value without requiring real-time network intervention, thereby improving system efficiency while keeping the overall system structure simple and manageable.
3Loss of time
If UE-specific dynamic discard timer selection is implemented, then latency is reduced and efficiency improved, but device complexity increases
Solution Approach 1:
The patent manages UE processing complexity by changing the approach from calculating optimal timer values to selecting from pre-configured candidate values. The network entity provides a limited set of discard timer values and selection parameters, which constrains the UE's selection task and reduces processing complexity while still enabling dynamic, latency-optimized timer configuration specific to each UE's conditions.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. For example, a user equipment (UE) may be capable of performing a discard timer selection procedure for a discard timer associated with a packet data convergence protocol (PDCP) layer of a protocol stack of the UE. The UE may receive, from the network entity, a control message indicating one or more selection parameters for the discard timer selection procedure of the UE. In response to receiving the control message, the UE may perform the discard timer selection procedure to obtain a discard timer value for the discard timer. The UE may store one or more PDCP service data units (SDUs) associated with an uplink message for the UE according to the selected discard timer value, such that one or more of the stored PDCP SDUs may be dropped upon expiration of an associated discard timer.