NR Flow-Control Feedback for SCG Split-Bearer Latency
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Solution Overview
Problem
Existing wireless communication systems, particularly in LTE and LTE-Advanced, lack efficient network-based flow control mechanisms for dual connectivity, especially in scenarios involving secondary cell group (SCG) split-bearer operations and packet data convergence protocol (PDCP) duplication, leading to inefficiencies and challenges in meeting latency and reliability targets.
Innovation Solution
Enhancements are introduced for network-based flow control, including support for uplink and downlink operations, SCG split-bearer operations, and PDCP duplication, through modifications to frame formats and feedback mechanisms, such as UL/DL USER DATA and DELIVERY STATUS messages, with features like polling, periodicity, and threshold-based reporting to optimize scheduling and reduce duplicative transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDCP duplication is implemented for reliability, then reliability improves, but duplicative transmissions increase latency
Solution Approach 1:
The patent implements feedback mechanisms where the receiving node sends delivery status information back to the transmitting node. This feedback enables the transmitting node to determine which duplicated packets have been successfully received and which need retransmission, thereby reducing unnecessary retransmissions and lowering latency while maintaining reliability through selective retransmission based on actual delivery status.
Solution Approach 2:
The patent enables the receiving node to discard duplicate packets that have already been successfully received by comparing sequence numbers against previously received packets. This discarding mechanism prevents duplicative transmissions from consuming additional latency, while the recovery mechanism allows the system to request retransmission only of packets that were actually lost, optimizing the balance between reliability and latency.
2Productivity
If flow control mechanisms are enhanced for dual connectivity, then network performance improves, but device complexity increases
Solution Approach 1:
The patent extends the flow control mechanism to be universal across both master cell group (MCG) and secondary cell group (SCG) bearers in dual connectivity scenarios. The same delivery status reporting and packet discarding mechanisms apply to both regular bearers and split bearers, allowing a single unified flow control approach to improve network performance across multiple connectivity modes without requiring separate complex mechanisms for each case.
Solution Approach 2:
The patent segments the flow control functionality into distinct modular components: packet transmission, delivery status reporting, duplicate detection, and selective retransmission. This segmentation allows each component to be independently implemented and optimized, reducing overall device complexity while enabling enhanced flow control for dual connectivity through composition of these manageable functional blocks.
3Loss of time
If duplicative transmissions are reduced, then latency decreases, but reliability may be compromised without proper feedback
Solution Approach 1:
The patent implements feedback mechanisms where the receiving node sends delivery status information back to the transmitting node. This feedback enables the transmitting node to determine which duplicated packets have been successfully received and which need retransmission, thereby reducing unnecessary retransmissions and lowering latency while maintaining reliability through selective retransmission based on actual delivery status.
Data Source
AI summary
Devices, methods, communication nodes, base stations, storage media, and other embodiments are provided for managing associations in a communication network. In one example embodiment, a New Radio (NR) node is configured for NR user-plane protocol communications between a master node (MN) and a secondary node (SN). The NRnode is configured to generate a downlink (DL) user data message with downlink user data, initiate transmission of the DL user data message to a second node, and process a DL data delivery status message from the second node in response to the DL user data message. In various embodiments, polling and SCG split-bearer configurations are supported by such messaging. In some embodiments, packet data convergence protocol (PDCP) serial numbers are communicated for transmission and retransmission management. In some embodiments, DL configurations initiated by an SN are enabled, as well as UL configurations initiated by either an MN or an SN.