RLC SDU Retransmission Using PDCP Remaining-Time Thresholds
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Solution Overview
Problem
The challenge in mobile wireless communication systems, particularly in 5G networks, is the inefficient handling of data bursts from Extended Reality (XR) services, which require stringent delay budgets and often result in excessive resource waste due to inadequate uplink scheduling techniques.
Innovation Solution
The method involves receiving a Radio Resource Control (RRC) message with parameters for radio bearers and performing retransmission of specific Radio Link Control (RLC) Service Data Units (SDUs) based on a remaining time threshold and maximum retransmission number, enhancing retransmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional uplink scheduling techniques are used for XR services, then resource allocation is simplified, but delay requirements are not met and resource waste increases
Solution Approach 1:
The patent applies preliminary action by performing retransmission of RLC SDUs before the PDCP discard timer expires. The UE proactively retransmits data segments when remaining time becomes less than a threshold, ensuring delivery before the original delay budget is exhausted, thus meeting XR service delay requirements while avoiding waste of radio resources on expired data
Solution Approach 2:
The patent implements dynamics by making the retransmission decision adaptive based on the remaining time of PDCP SDUs. The UE dynamically adjusts retransmission behavior by monitoring the remaining time threshold and selectively retransmitting only those RLC SDUs whose associated PDCP SDUs have not yet expired, optimizing resource usage according to real-time delay constraints
2Reliability
If retransmission of all RLC SDUs is performed, then delivery reliability is improved, but resource consumption increases
Solution Approach 1:
The patent applies local quality by performing selective retransmission rather than blanket retransmission of all RLC SDUs. The UE identifies and retransmits only those specific RLC SDUs whose associated PDCP SDUs have remaining time greater than the threshold, applying different treatment (retransmission vs. discard) to different data segments based on their individual delay status, thus improving reliability for deliverable data while conserving resources for expired data
Solution Approach 2:
The patent uses parameter changes by introducing a remaining time threshold parameter that controls retransmission behavior. The UE monitors the remaining time of PDCP SDUs and changes retransmission decisions based on whether this parameter exceeds the threshold, dynamically adjusting the set of RLC SDUs to be retransmitted according to the current delay status of associated PDCP data
Data Source
AI summary
A method and apparatus to support enhanced retransmission is provided. Method for supporting enhanced retransmission includes receiving from a base station a Radio Resource Control (RRC) message, wherein the RRC message comprises a parameter indicating a remaining time threshold related to a radio bearer and a parameter indicating a maximum retransmission number for a Radio Link Control (RLC) entity that is associated with the radio bearer, and performing retransmission of a specific RLC Service Data Unit (SDU) in case that at least one byte of the specific RLC SDU has been transmitted and remaining time of a Packet Data Convergence Protocol (PDCP) SDU associated the specific RLC SDU becomes less than the remaining time threshold.