UE Downlink Flow Control via PDCP Packet Dropping
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Solution Overview
Problem
In wireless communication systems, particularly in LTE networks, user equipment (UE) faces challenges in managing downlink data flow due to resource limitations such as memory size and processing power, leading to potential data loss and congestion, which existing methods do not adequately address.
Innovation Solution
The UE monitors parameters like temperature, memory, and processing power to selectively drop packets at the PDCP layer before transferring them to the applications processor, triggering a rate control mechanism to reduce TCP throughput and free resources, thereby implementing downlink flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE continues to receive and buffer downlink packets at high rate, then the data throughput is improved, but the buffer overflow and data loss increase due to resource limitations
Solution Approach 1:
The patent implements downlink flow control by monitoring UE buffer status and packet processing capability, then feeding back this information to the base station to adjust downlink transmission rate. The UE monitors parameters such as buffer occupancy, packet processing speed, and temperature, and uses this feedback to dynamically control packet dropping rates, thereby preventing buffer overflow while maintaining optimal throughput.
Solution Approach 2:
The patent dynamically changes the packet dropping rate parameter based on real-time UE resource status. When buffer occupancy exceeds thresholds or processing resources are constrained, the packet dropping rate is increased to prevent overflow. Conversely, when resources are abundant, the dropping rate is reduced to maximize throughput. This dynamic parameter adjustment resolves the contradiction between maintaining high throughput and preventing data loss.
2Reliability
If the UE implements strict packet filtering to prevent data loss, then data reliability is improved, but the processing overhead and resource consumption increase
Solution Approach 1:
Instead of implementing strict packet filtering for all packets, the patent applies partial filtering based on priority and buffer status. The system selectively drops only excess packets when buffer occupancy exceeds thresholds, rather than filtering all incoming packets. This partial action approach prevents data loss while minimizing processing overhead and resource consumption.
3Productivity
If the base station increases downlink transmission rate to improve throughput, then productivity is improved, but the UE buffer overflow and congestion increase
Solution Approach 1:
The base station receives feedback from the UE about buffer status, packet processing capability, and resource availability. Based on this feedback, the base station dynamically adjusts the downlink transmission rate to match UE capacity. When the UE indicates buffer near-capacity or processing constraints, the base station reduces transmission rate to prevent overflow. This feedback mechanism resolves the contradiction between maximizing throughput and preventing congestion.
Solution Approach 2:
The downlink transmission rate is made dynamic rather than fixed. The system continuously adapts the transmission rate based on real-time UE resource status, buffer occupancy, and packet processing speed. This dynamic adjustment allows the system to maximize throughput when resources are abundant and prevent overflow when resources are constrained, resolving the contradiction between productivity and harmful factors.
Data Source
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AI summary
Certain aspects of the present disclosure relate to wireless communications and methods and apparatus for downlink flow control at a user equipment (UE). Aspects generally include monitoring, by a UE, one or more parameters related to the UE (902), and selectively dropping received packets based on the one or more parameters in order to trigger a rate control mechanism (904). Selectively dropping received packets may occur at a Packet Data Convergence Protocol (PDCP) layer in order to reduce a corresponding transmission control protocol (TCP) throughput. Accordingly, packets may be selectively dropped prior to reaching an applications processor.