LCH Mapping Restrictions for Small Data in RRC Inactive

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Solution Overview

Problem

Existing wireless communication technologies do not support efficient small-data transmission in the RRC_INACTIVE state, leading to unnecessary power consumption and signaling overhead due to frequent transitions between RRC_CONNECTED and RRC_INACTIVE states for small data packets.

Innovation Solution

Configuring User Equipment (UE) with two sets of Logical Channel (LCH) mapping restrictions, one for RRC_CONNECTED and another for RRC_INACTIVE, allowing small-data transmission on pre-configured resources and enabling flexible payload sizes for RACH-based schemes, and using DCI to indicate allowed LCHs for uplink transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE transitions between RRC_CONNECTED and RRC_INACTIVE states for small data packets, then the UE can maintain proper connection management, but power consumption and signaling overhead increase

Engineering Contradiction:
Improveconnection managementVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The network pre-configures the UE with two sets of LCH mapping restrictions (first set for RRC_CONNECTED, second set for RRC_INACTIVE) before the UE needs to transmit small data. This preliminary configuration allows the UE to immediately apply the appropriate restrictions without state transition, reducing unnecessary power consumption and signaling overhead while maintaining proper connection management

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically switches between two sets of LCH mapping restrictions based on the UE's RRC state. The UE applies the first set of restrictions when in RRC_CONNECTED state and the second set when in RRC_INACTIVE state, enabling flexible adaptation to different operational modes without frequent state transitions

Inventive Principle:
Principle #15Dynamics

2Reliability

If the UE transitions between RRC_CONNECTED and RRC_INACTIVE states for small data packets, then the UE can maintain proper connection management, but signaling overhead increases

Engineering Contradiction:
Improveconnection managementVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The network provides preliminary configuration of both sets of LCH mapping restrictions in advance, so the UE has all necessary information stored locally. This eliminates the need for frequent signaling exchanges during small data transmissions, reducing signaling overhead while maintaining proper connection management

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The dynamic selection between first and second sets of LCH mapping restrictions based on RRC state allows the system to adapt to different operational contexts without requiring continuous network signaling, thereby reducing signaling overhead while maintaining connection management reliability

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the UE uses a single set of LCH mapping restrictions for both RRC_CONNECTED and RRC_INACTIVE states, then the configuration is simple, but small-data transmission efficiency is reduced

Engineering Contradiction:
Improveconfiguration complexityVSAvoidsmall-data transmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The LCH mapping restrictions are segmented into two distinct sets: the first set optimized for RRC_CONNECTED state and the second set optimized for RRC_INACTIVE state. This segmentation allows each set to be tailored for specific transmission requirements, improving small-data transmission efficiency while maintaining manageable configuration complexity through structured organization

Inventive Principle:
Principle #1Segmentation

4Productivity

If the UE applies different LCH mapping restrictions for RRC_CONNECTED and RRC_INACTIVE states, then small-data transmission efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvesmall-data transmission efficiencyVSAvoidconfiguration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system uses dynamic state-based selection between two sets of LCH mapping restrictions, where the UE automatically applies the first set in RRC_CONNECTED state and the second set in RRC_INACTIVE state. This dynamic approach improves small-data transmission efficiency by optimizing restrictions for each state while managing complexity through clear state-dependent rules

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4256896B1LCH configuration for small data transmission
Publication Date: 2026.03.25 LENOVO (SINGAPORE) PTE LTD
  • EP4256896B1 patent drawingFigure 1
  • EP4256896B1 patent drawingFigure 2
  • EP4256896B1 patent drawingFigure 3

AI summary

Apparatuses, methods, and systems are disclosed for configuring LCH mapping restriction for SDT. One apparatus (600) includes a transceiver (625) that receives (805) a configuration with logical channel ("LCH") mapping restrictions for an LCH. The apparatus (600) includes a processor (605) applies (810) a first set of LCH mapping restrictions for uplink transmissions when the first apparatus is in an RRC connected state and applies (815) a second set of LCH mapping restrictions for uplink transmissions when the first apparatus is in a RRC inactive state, where the LCH mapping restrictions of the first set are different than the LCH mapping restrictions of the second set.