5G RLC Data Retransmission via MAC-RLC Cross-Layer Feedback

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Solution Overview

Problem

Traditional wireless communication technologies in the 5G RLC layer face challenges in meeting real-time requirements for low-latency services due to inefficiencies in data retransmission processes, particularly in utilizing uplink resources effectively.

Innovation Solution

A cross-layer collaboration method is implemented, where the MAC layer of the transmitting end immediately reports index information of data unit packets with negative feedback to the RLC layer, enabling faster retransmission without waiting for control PDU feedback from the receiving end.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple error response signals NACK are sent at MAC layer before feedback to RLC layer, then uplink resources are reasonably utilized, but real-time requirements of low-latency services are not met

Engineering Contradiction:

Improveuplink resource utilization efficiencyVSAvoidretransmission latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent segments the feedback process into two independent paths: MAC layer sends NACK immediately upon detecting errors, while RLC layer processes feedback separately. This segmentation allows the MAC layer to respond quickly without waiting for RLC layer processing, reducing overall latency while maintaining resource utilization efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The MAC layer performs preliminary action by sending NACK feedback immediately when errors are detected, before the RLC layer has finished processing. This preliminary feedback mechanism ensures that retransmission can start as soon as possible, addressing the real-time requirements of low-latency services.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If traditional RLC layer retransmission process is used, then protocol compatibility is maintained, but retransmission efficiency and accuracy are insufficient

Engineering Contradiction:

Improveprotocol compatibilityVSAvoidretransmission efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges the feedback mechanisms of MAC layer and RLC layer into a unified retransmission process. The MAC layer's immediate NACK feedback is combined with the RLC layer's processing logic, creating a hybrid system that maintains protocol compatibility while significantly improving retransmission efficiency and accuracy through cross-layer collaboration.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250047414A1Radio link control layer data retransmission method, apparatus, system, and storage medium

Publication Date: 2025.02.06 LENOVO (BEIJING) LTD

AI summary

A radio link control (RLC) layer data retransmission method includes: sending, by a first media access control (MAC) layer of a transmitting end, at least one code block group (CBG), each CBG including at least one data unit packet, and records index information of each corresponding data unit packet; within a timeslot period and before receiving feedback, receiving feedback information from a second MAC layer of a receiving end for each CBG; reporting, by the first MAC layer, the index information of each data unit packet corresponding to the CBG whose feedback information is negative to a first RLC layer of the transmitting end; and retransmitting, by the first RLC layer, the data unit packet whose feedback information is negative.