Terminal Device Downlink Flow Control in 5G Multi-Point Diversity
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Solution Overview
Problem
5G mobile communication networks face limitations in flow control for downlink multi-point diversity due to weak radio links and high backhaul latency, especially at higher frequency bands, which hinder effective transmission diversity and increase latency.
Innovation Solution
The terminal device measures downlink transmission information from multiple network nodes and makes flow control decisions internally, sending instructions directly to the network nodes to bypass backhaul latency and improve flow control reactivation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If network-based flow control solutions are used in 5G systems, then flow control decisions can be made centrally, but backhaul latency causes performance degradation and delays
Solution Approach 1:
The patent introduces a distributed flow control mechanism where the UE acts as an intermediary that makes local flow control decisions based on measured downlink transmission information. Instead of relying solely on centralized network decisions that suffer from backhaul latency, the UE autonomously determines whether to send measurement reports and triggers flow control actions locally, thereby bypassing the latency bottleneck while still achieving coordinated flow control across multiple access points.
2Measurement precision
If UE measurement feedback is required for flow control, then flow control decisions can be made accurately, but transmission of measurement reports may fail when radio link crashes
Solution Approach 1:
The patent implements preliminary action by having the UE continuously monitor downlink transmission information and pre-evaluate the quality of the measurement report transmission link. When the UE detects that the radio link quality is below a threshold or that transmission failure is likely, it proactively decides not to send the measurement report, thereby avoiding the transmission failure. This preliminary assessment and conditional reporting mechanism ensures that flow control decisions are based on reliable measurements while preventing wasted transmission attempts on degraded links.
3Speed
If 5G air interface capability is improved, then radio link latency is reduced, but backhaul latency remains the bottleneck limiting flow control performance
Solution Approach 1:
The patent extracts the flow control decision-making function from the centralized network entity and relocates it to the UE. By taking out the measurement report transmission and flow control triggering functions from the network-based architecture, the system eliminates the backhaul latency bottleneck that limited flow control performance. The UE independently evaluates downlink transmission quality and triggers flow control actions locally, thereby separating the fast radio link operations from the slower backhaul communication and achieving low-latency flow control in 5G systems.
Data Source
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AI summary
One embodiment of the present disclosure relates to a method for operating in a terminal device for downlink flow control. The terminal device receives duplicated packets from a first network node device and one or more secondary network node devices. The method comprises measuring downlink transmission information for the first network node device and the one or more secondary network node devices; deciding downlink flow control information based on the measured downlink transmission information; and sending the downlink flow control information to at least the first network node device. According to other aspects of the present disclosure, there are provided corresponding methods and devices.