Small Data Transmission Configuration for Inactive User Equipment

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently managing small data transmission (SDT) for user equipment (UE) operating in an inactive or idle state, particularly in configuring UE with SDT parameters when transitioning between radio resource control (RRC) states.

Innovation Solution

A central unit (CU) of a base station determines to configure or reconfigure a UE for SDT operation by requesting a SDT DU configuration from a distributed unit (DU) via CU-to-DU messages, and subsequently sends the SDT DU and CU configurations to the UE, enabling efficient SDT even in inactive states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE transitions to RRC_CONNECTED state for data transmission, then reliable data communication is achieved, but transition time and latency increase

Engineering Contradiction:

Improvedata communication reliabilityVSAvoidstate transition latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The network configures SDT parameters and resources in advance while the UE is in RRC_CONNECTED state, storing them in the inactive state. When small data needs to be transmitted, the UE can immediately use the pre-configured SDT resources without transitioning to RRC_CONNECTED, thereby reducing latency while maintaining communication reliability.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If the UE remains in RRC_IDLE or RRC_INACTIVE state for small data transmission, then transition latency is reduced, but configuration complexity increases

Engineering Contradiction:

Improvestate transition latencyVSAvoidSDT configuration complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The SDT configuration is segmented into multiple components: SDT parameters (data volume thresholds, RSRP thresholds), SDT resources (random access resources, configured grant resources), and SDT procedure parameters. This segmentation allows the network to flexibly configure only the necessary components for each UE scenario, reducing overall configuration complexity while enabling low-latency small data transmission.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If SDT configuration is provided for all UEs, then small data transmission capability is improved, but signaling overhead increases

Engineering Contradiction:

ImproveSDT transmission capabilityVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

Instead of providing uniform SDT configuration to all UEs, the network applies local quality by configuring SDT parameters specifically for UEs that meet certain criteria (e.g., UEs with small data transmission needs, UEs in specific coverage conditions). The SDT configuration is provided selectively through dedicated RRC signaling or system information blocks, reducing overall signaling overhead while maintaining SDT capability for target UEs.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250175814A1Managing radio resource configurations for small data communication

Publication Date: 2025.05.29 GOOGLE LLC

AI summary

In a method of handling small data transmission (SDT) with a user equipment (UE), a DU communicates (318 or 418) with the UE in accordance with a first DU configuration. While communicating with the UE in accordance with the first DU configuration, the DU determines that there is data inactivity of the UE. The DU transmits an indication of UE data inactivity to the CU (322 or 422). After transmitting the indication, the DU receives (328 or 428), from the CU, a CU-to-DU message requesting a SDT DU configuration for the UE, and transmits (332 and 334, or 432 and 434) a SDT DU configuration to the UE.