RRC Inactive State Downlink Data Reception Mechanism

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Solution Overview

Problem

Current wireless communication systems do not provide a method for user equipment (UE) in the RRC_INACTIVE state to perform data transmission and reception, nor do they outline the procedures for a base station to control data transmission and reception with a UE in this state.

Innovation Solution

A method for a UE in the RRC_INACTIVE state to receive downlink user data involves entering the RRC_INACTIVE state, receiving a notification indication from the base station, transmitting its ID, and receiving data units based on the indication, utilizing a processor and transceiver to manage these operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a UE enters RRC_INACTIVE state to reduce power consumption, then energy efficiency is improved, but the ability to receive downlink user data is lost

Engineering Contradiction:
Improvepower consumptionVSAvoiddata reception capability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a dynamic mechanism where the UE can transition between RRC_INACTIVE and RRC_CONNECTED states based on downlink data arrival. The network can trigger state transitions by sending notification indications, allowing the system to adapt between power-saving mode and active data reception mode dynamically

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The network performs preliminary actions by maintaining context information and sending notification indications to UEs in RRC_INACTIVE state before data transmission. This allows the UE to be prepared for data reception without being in a fully connected state, enabling efficient state management

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a UE maintains RRC_CONNECTED state to receive downlink user data, then data reception capability is improved, but power consumption increases

Engineering Contradiction:
Improvedata reception capabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic monitoring where UEs in RRC_INACTIVE state wake up at specific intervals to check for notification indications from the network. This periodic action allows the UE to maintain power-saving mode while still being able to receive downlink data when available

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The network autonomously manages the UE's state by sending notification indications without requiring the UE to continuously monitor or request data. The UE simply responds to notifications, reducing its operational complexity and power consumption

Inventive Principle:
Principle #25Self-service

3Reliability

If a UE transitions from RRC_INACTIVE to RRC_CONNECTED to receive data, then data transmission and reception is enabled, but control procedure complexity increases

Engineering Contradiction:
Improvedata transmission capabilityVSAvoidcontrol procedure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential data reception functionality from the full RRC_CONNECTED state, allowing UEs to receive downlink data while remaining in RRC_INACTIVE state. This extraction eliminates the need for complex state transitions while maintaining core data reception capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The notification indication acts as an intermediary mechanism between the network and UE, enabling data transmission without requiring full connection establishment. This intermediary simplifies the control procedure by providing a lightweight signaling mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3537826B1Method and device for receiving downlink user data
Publication Date: 2021.07.21 LG ELECTRONICS INC
  • EP3537826B1 patent drawingFigure 1
  • EP3537826B1 patent drawingFigure 2
  • EP3537826B1 patent drawingFigure 3

AI summary

A method for a terminal to receive downlink user data in a wireless communication system and a device supporting the method are provided. The method may comprise: a step of entering an RRC_INACTIVE state; a step of receiving, from a base station, a notification indication indicating if downlink data is transmitted in the RRC _INACTIVE state; a step of transmitting an ID of a terminal to the base station; and a step of receiving, based on the indication, a data unit from the base station in the RRC _INACTIVE state.