UE Temporary Identifier Handling in Small Data Transmission Sessions

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Solution Overview

Problem

The management of small data transmission configuration parameters for user equipment (UE) in inactive or idle states associated with a radio access network (RAN) is unclear, particularly in scenarios involving Small Data Transmission (SDT) procedures, leading to inefficiencies in handling downlink and uplink data without transitioning to a connected state.

Innovation Solution

The UE monitors downlink control channels during RA-SDT and CG-SDT sessions using temporary identifiers, and upon receiving indications, stops monitoring and retains these identifiers, allowing for efficient management of SDT configuration parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the UE transitions to RRC_CONNECTED state for data transmission, then data transmission capability is improved, but state transition overhead and latency increase

Engineering Contradiction:

Improvedata transmission capabilityVSAvoidstate transition latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent segments the data transmission process by enabling small data transmissions directly in RRC_INACTIVE state through SDT procedures. This allows the UE to transmit small packets without transitioning to RRC_CONNECTED, thereby avoiding state transition latency while maintaining data transmission capability for small packets.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The network configures SDT resources and parameters in advance while the UE is in RRC_INACTIVE state. This preliminary configuration includes allocating uplink resources, setting timing alignment parameters, and providing grant configurations, so that when small data needs to be transmitted, the UE can immediately use these pre-configured resources without state transition overhead.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the UE monitors downlink control channels continuously, then downlink data reception capability is improved, but energy consumption increases

Engineering Contradiction:

Improvedownlink data reception capabilityVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The UE monitors downlink control channels periodically based on configured monitoring occasions rather than continuously. The network configures specific monitoring periods and occasions for the UE to check for downlink assignments during SDT, allowing the UE to enter low-power states between monitoring occasions while still being able to receive downlink data when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The UE uses pre-configured SDT parameters and resources to autonomously manage its monitoring behavior. The UE determines when to monitor based on configured grants and timing alignment validity without requiring continuous network control, enabling energy-efficient autonomous operation in RRC_INACTIVE state.

Inventive Principle:

Principle #25Self-service

3Device complexity

If the UE releases SDT configuration parameters after SDT session, then resource management is simplified, but re-establishment time increases

Engineering Contradiction:

Improveconfiguration management complexityVSAvoidre-establishment time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The UE releases SDT configuration parameters after completing an SDT session to free up resources, but retains the ability to quickly re-establish SDT by obtaining new configuration parameters through RAN paging or system information broadcasts. This approach balances resource management with quick re-establishment capability.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The network maintains pre-configured SDT parameter templates and resource allocations that can be quickly re-applied to UEs. When a UE needs to re-establish SDT, the network can rapidly provide configuration parameters through efficient signaling mechanisms, reducing re-establishment time while allowing the UE to release detailed configurations after use.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4487645B1Managing small data transmission configuration parameters when detecting a failure

Publication Date: 2026.02.18 GOOGLE LLC

Figure 1A
Figure 1B~2A
Figure 2B

AI summary

A user equipment (UE) communicating with a radio access network (RAN) node can implement a method for monitoring a downlink control channel during a random access small data transmission (RA-SDT) session. The method includes: (i) receiving, at the UE and from the RAN node, a random access procedure message including a temporary identifier for the UE; (ii) monitoring, at the UE and during the RA-SDT session, the downlink control channel using the temporary identifier; (iii) receiving, at the UE and from the RAN node, an indication to end the RA-SDT session; and (iv) responsive to the receiving of the indication, stopping, at the UE, the monitoring of the downlink control channel using the temporary identifier.