DRX Cycle Switching for RRC Inactive Data Reception

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Solution Overview

Problem

Current methods for transmitting downlink data to a terminal in the RRC_INACTIVE state result in radio resource waste, large delays, and poor battery saving, as they either require unnecessary resource allocation or involve inefficient state transitions.

Innovation Solution

A method where a terminal in the RRC_INACTIVE state receives configuration for a first and second DRX cycle, determines if downlink data transmission is indicated without state transition, and switches to the second DRX cycle for efficient data reception, thereby reducing resource waste and delay while improving battery life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If downlink data is transmitted to terminal in RRC_INACTIVE state using conventional methods, then data transmission is achieved, but radio resource waste occurs

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidradio resource waste
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent changes the DRX cycle parameter from a first DRX cycle to a second DRX cycle when downlink data is detected, optimizing resource usage by adjusting the monitoring periodicity parameter to match current traffic conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically switches between different DRX cycle configurations based on real-time data transmission needs, transitioning from a conservative first DRX cycle to a more efficient second DRX cycle when data is present

Inventive Principle:
Principle #15Dynamics

2Productivity

If terminal transitions to RRC_CONNECTED state for data transmission, then data can be transmitted, but transmission delay increases

Engineering Contradiction:
Improvedata transmission capabilityVSAvoidstate transition delay
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The network performs preliminary actions by detecting downlink data and notifying the terminal in advance while it remains in RRC_INACTIVE state, allowing the terminal to prepare for data reception without completing the full state transition to RRC_CONNECTED

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the essential data transmission function from the complete RRC state transition process, allowing data to be transmitted and received in RRC_INACTIVE state by separating the data path from the control plane state machine

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of time

If terminal frequently monitors for downlink data in RRC_INACTIVE state, then data reception is timely, but battery consumption increases

Engineering Contradiction:
Improvedata reception delayVSAvoidbattery consumption
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The terminal uses periodic DRX cycles to monitor for downlink data instead of continuous monitoring, waking up at scheduled intervals defined by the DRX cycle to check for data, thereby reducing battery consumption while maintaining timely data reception

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The DRX cycle parameter is adjusted from a first DRX cycle to a second DRX cycle based on data presence, optimizing the monitoring periodicity to balance between power savings and data reception timeliness

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If terminal uses first DRX cycle for data transmission, then battery saving is achieved, but transmission efficiency decreases

Engineering Contradiction:
Improvebattery savingVSAvoiddata transmission efficiency
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The system dynamically adapts the DRX cycle configuration based on real-time conditions, switching from a battery-optimized first DRX cycle to a more efficient second DRX cycle when data transmission is required, and switching back when data transmission is complete

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The DRX cycle parameter is changed from first DRX cycle to second DRX cycle in response to data transmission needs, allowing the system to optimize between power consumption and transmission efficiency by adjusting the monitoring periodicity parameter

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3554183B1Method and device for terminal transmitting/receiving data
Publication Date: 2021.03.03 LG ELECTRONICS INC
  • EP3554183B1 patent drawingFigure 1
  • EP3554183B1 patent drawingFigure 2
  • EP3554183B1 patent drawingFigure 3

AI summary

Provided are a method for a terminal receiving downlink data in a wireless communication system, and a device supporting same. The method may comprise the steps of: entering a radio resource control (RRC)_INACTIVE state; receiving a configuration associated with a first DRX cycle and a second DRX cycle; receiving a first paging message on the basis of the first DRX cycle; stopping the use of the first DRX cycle if the first paging message indicates that downlink data has been transmitted to the terminal without an RRC state transition; and receiving the downlink data from a base station in the RRC_INACTIVE state on the basis of the second DRX cycle.