5G Inactive UE Downlink Data Transmission via MSG3

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Solution Overview

Problem

5G networks face challenges in transmitting downlink data to User Equipment (UE) in an inactive state, as LTE networks do not support this functionality, leading to inefficiencies in data transmission.

Innovation Solution

A method and device for directly transmitting downlink data to a UE in an inactive state in a 5G network, using paging signaling, random access, and RRC connection recovery requests to enable efficient data transmission through specific message exchanges (MSG3 and MSG4) between the UE and the base station.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If downlink data transmission to inactive UE is not supported (LTE approach), then network complexity is reduced, but data transmission efficiency deteriorates

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidnetwork complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the RRC state transitions flexible and conditional. The UE can dynamically transition between inactive and connected states based on downlink data arrival, enabling adaptive response to traffic conditions rather than fixed state management

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary mechanism through the MSG4 message that carries both RRC connection recovery and downlink data simultaneously. This intermediary message structure enables indirect data delivery to inactive UEs through the random access procedure, bridging the gap between inactive state and data transmission capability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If UE transitions to connected state for downlink data reception, then data transmission reliability is improved, but energy consumption increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidUE energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by allowing UEs to remain in inactive state for minimal data transmissions. The UE only transitions to connected state when necessary, using the random access procedure for small amounts of data rather than maintaining full connection, thus reducing unnecessary energy consumption while ensuring reliable delivery when needed

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the parameter of RRC state from static to dynamic, allowing transition between inactive and connected states based on traffic conditions. This parameter change enables the system to optimize energy consumption by maintaining UEs in low-power inactive state during idle periods while ensuring reliable data transmission when data arrives

Inventive Principle:
Principle #35Parameter changes

3Speed

If direct downlink data transmission to inactive UE is implemented, then data transmission speed is improved, but protocol complexity increases

Engineering Contradiction:
Improvedata transmission speedVSAvoidprotocol complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the MSG4 message, which simultaneously carries RRC connection recovery information and downlink data. This consolidation eliminates the need for separate signaling messages, enabling direct data transmission to inactive UEs while managing protocol complexity through message multiplexing

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3675532B1Downlink data transmission method and device, user equipment, and base station
Publication Date: 2024.04.17 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3675532B1 patent drawingFigure 1~2A
  • EP3675532B1 patent drawingFigure 2B~3
  • EP3675532B1 patent drawingFigure 4

AI summary

The present disclosure relates to a downlink data transmission method and device, a User Equipment (UE), a base station, and a computer-readable storage medium. The downlink data transmission method is applied to a UE in an inactive state. The method includes: receiving paging signaling from a base station; initiating a random access according to the paging signaling, and sending a third message MSG3 to the base station, the MSG3 including a Radio Resource Control (RRC) connection recovery request; and receiving a fourth message MSG4 from the base station, the MSG4 including RRC connection recovery and downlink data to be sent. In embodiments of the disclosure, downlink data may be directly transmitted to a UE in an inactive state in a 5G network, and downlink data transmission is completed through an MSG3 and an MSG4, thus improving data transmission efficiency.