NB-IoT Terminal DRX Timer Control for Power Efficiency

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current LTE and NB-IoT communication systems face inefficiencies in power consumption and DRX handling due to half-duplex transmission and limited HARQ processes, which affect communication efficiency between terminal apparatuses and base stations.

Innovation Solution

The proposed solution involves modifying the DRX timers and start/stop criteria for NB-IoT UE, specifically starting the drx-InactivityTimer after successful uplink transmission and stopping it upon receiving a downlink or uplink grant, to reduce NB-PDCCH monitoring time and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal apparatus continuously monitors NB-PDCCH to ensure reliable communication, then communication reliability is improved, but power consumption increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements discontinuous reception (DRX) where the terminal apparatus periodically monitors NB-PDCCH during active time and enters sleep mode during inactive time. The drx-InactivityTimer creates periodic monitoring intervals triggered by downlink assignments, allowing the terminal to balance between monitoring for reliable communication and sleeping to conserve power.

Inventive Principle:

Principle #19Periodic action

2Speed

If the terminal apparatus monitors NB-PDCCH frequently to detect downlink assignments quickly, then response speed is improved, but NB-PDCCH monitoring time increases

Engineering Contradiction:

Improveresponse speedVSAvoidNB-PDCCH monitoring time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The patent dynamically adjusts NB-PDCCH monitoring behavior based on communication state. The terminal transitions between continuous monitoring and periodic monitoring based on drx-InactivityTimer status, adapting monitoring intensity to actual downlink data arrival patterns and minimizing unnecessary monitoring while maintaining responsive detection.

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If the terminal apparatus reduces NB-PDCCH monitoring time to save power, then power consumption is reduced, but communication efficiency deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidcommunication efficiency

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent uses feedback from downlink assignment reception to control monitoring behavior. When a downlink assignment is received, the drx-InactivityTimer is restarted, triggering periodic monitoring. This feedback mechanism ensures monitoring resumes when downlink data is present, maintaining communication efficiency while allowing power savings during inactive periods.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3410784B1Terminal device, communication method, and integrated circuit

Publication Date: 2020.12.16 SHARP KK

Figure 1
Figure 2
Figure 3

AI summary

A terminal apparatus and a base station apparatus are capable of efficiently communicating with each other. A terminal apparatus monitors an NB-PDCCH, performs a DRX functionality that controls monitoring of the NB-PDCCH, starts a downlink HARQ RTT timer, based at least on the NB-PDCCH indicating a downlink transmission, starts an uplink HARQ RTT timer, based at least on the NB-PDCCH indicating an uplink transmission, starts a drx-InactivityTimer, based at least on the downlink HARQ RTT timer expires, starts the drx-InactivityTimer, based at least on the uplink HARQ RTT timer expires, and stops the drx-InactivityTimer, based at least on the NB-PDCCH indicating the downlink transmission or the uplink transmission.