RRC Inactive Small Data Transmission in 5G NR

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Solution Overview

Problem

In 5G New Radio (NR) communication, user equipment (UEs) in the RRC_INACTIVE state cannot transmit data, leading to inefficient and power-consuming connection building and releasing for small and infrequent data transmissions.

Innovation Solution

The method involves transmitting a control message from a first wireless communication node to a second node to instruct a UE to enter the RRC_INACTIVE mode and configure it for small data transmission (SDT), while preventing the release of associated information for SDT purposes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If UEs enter RRC_INACTIVE state to reduce power consumption, then power consumption is reduced, but data transmission capability is lost

Engineering Contradiction:

Improvepower consumptionVSAvoiddata transmission capability

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent changes the state parameters of the UE by introducing a new RRC state (RRC_INACTIVE) that differs from both RRC_CONNECTED and RRC_IDLE. This state allows the UE to maintain certain parameters (like AS context) while reducing others (like full connection establishment), enabling limited data transmission capability with reduced power consumption compared to RRC_CONNECTED state.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If UEs resume connections for small data transmission, then data transmission capability is restored, but connection building and releasing becomes inefficient and power consuming

Engineering Contradiction:

Improvedata transmission capabilityVSAvoidconnection building and releasing overhead

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by pre-configuring the UE with SDT configuration information and maintaining AS context during the RRC_INACTIVE state. This preliminary preparation allows the UE to perform small data transmissions without needing to fully resume the complete connection, thereby avoiding the overhead of full connection building and releasing for each small data transmission.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If UEs cannot transmit data in RRC_INACTIVE state, then power consumption is reduced, but small data transmission efficiency is compromised

Engineering Contradiction:

Improvepower consumptionVSAvoidsmall data transmission efficiency

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent segments the data transmission function by introducing a dedicated Small Data Transmission (SDT) mechanism that operates independently from the full connection resume procedure. This segmentation allows small data transmissions to occur in RRC_INACTIVE state using simplified procedures (like configured grant type-1 or 2-step RACH) rather than requiring full connection establishment, thus maintaining transmission efficiency while preserving power savings.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250168916A1Method, device and computer program product for wireless communication

Publication Date: 2025.05.22 ZTE CORP

AI summary

Method, device and computer program product for wireless communication are provided. A method includes: transmitting, by a first wireless communication node, a control message to a second wireless communication node, to control the second wireless communication node to instruct a wireless communication terminal to enter a radio resource control, RRC, inactive mode and transmitting at least one small data transmiexemplssion, SDT, configuration to the wireless communication terminal.