Small Data Transmission Rejection for Congested 5G NR Cells

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Solution Overview

Problem

In 5G NR systems, frequent small data transmissions lead to excessive signaling resource occupation due to frequent RRC state switching, resulting in resource wastage.

Innovation Solution

A data transmission method that allows a serving access network device to reject or terminate Small Data Transmission (SDT) when resource congestion occurs, providing redirection or cell reselection parameters to the terminal device, thereby improving data transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the UE frequently switches from RRC inactive state to RRC connected state for small data transmission, then data transmission capability is maintained, but signaling resources are excessively occupied

Engineering Contradiction:
Improvedata transmission capabilityVSAvoidsignaling resource occupation
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent extracts the data transmission function from the complete RRC connected state and allows it to operate independently in the RRC inactive state through SDT. This separation enables small data packets to be transmitted without requiring full RRC state switching, thereby reducing signaling resource occupation while maintaining data transmission capability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If the serving access network device continues to allocate resources for congested SDT, then resource allocation simplicity is maintained, but data transmission delay increases

Engineering Contradiction:
Improveresource allocation simplicityVSAvoiddata transmission delay
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent implements preliminary congestion detection and SDT termination mechanisms in the serving access network device. When congestion is detected, the device proactively terminates SDT and redirects the UE to an anchor access network device before actual data transmission occurs. This preliminary action prevents resource allocation waste and reduces transmission delay by avoiding failed transmission attempts.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the SDT is terminated or rejected by the serving access network device, then data transmission efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidcontrol mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces the anchor access network device as an intermediary to handle SDT when the serving access network device is congested. The serving device can quickly terminate SDT and redirect to the anchor device without complex local resource management decisions. This intermediary approach improves transmission efficiency while keeping the serving device's control logic relatively simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4418733B1Data transmission methods
Publication Date: 2025.09.17 HONOR DEVICE CO LTD
  • EP4418733B1 patent drawingFigure 1
  • EP4418733B1 patent drawingFigure 2
  • EP4418733B1 patent drawingFigure 3

AI summary

This application provides a data transmission method, an apparatus, and a system, which are applied to the field of communication technologies. The data transmission method includes: receiving, by a serving access network device, a first radio resource control RRC message from a terminal device, where the first RRC message is used to establish small data transmission SDT; and if the serving access network device does not meet a requirement of the SDT, sending a second RRC message or a third RRC message to the terminal device, where the second RRC message may be used to indicate the terminal device to terminate the SDT, and the third RRC message may be used to indicate the serving access network device to reject performing the SDT. Based on this solution, once the serving access network device does not meet the requirement of the SDT, the SDT may be rejected or terminated, so that the terminal device can subsequently reselect a cell to initiate the SDT again. Compared with a solution in which a terminal continues to wait in a current cell, data transmission efficiency of the terminal device can be improved.