Discontinuous Reception Period Control for Mobile Network Power Saving

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Solution Overview

Problem

Current discontinuous reception (DRX) systems in mobile radio communications networks, particularly in LTE systems, are limited in power-saving due to the need for frequent uplink timing updates, which restricts DRX periods, especially for slowly moving User Equipment (UE) handsets, as existing methods require periodic updates based on maximum permitted TA inaccuracy.

Innovation Solution

The method controls the magnitude of the discontinuous reception period responsive to the velocity of the mobile device, using timing offset signals from downlink signaling to determine velocity and adjust DRX periods, allowing longer sleep times for slowly moving devices while maintaining uplink timing synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If periodic uplink timing updates are performed at a fixed rate (e.g., 2 Hz) to account for the fastest UE speed, then uplink timing synchronization is maintained, but the DRX period is limited to less than 0.5 second, reducing power-saving potential

Engineering Contradiction:
Improveuplink timing synchronizationVSAvoidpower-saving
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the DRX period variable rather than fixed. The DRX period is dynamically adjusted based on the actual velocity of the UE, allowing the system to adapt between different operational states (high mobility vs. low mobility) and resolve the contradiction between maintaining synchronization and maximizing power-saving.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of DRX period based on UE velocity conditions. By monitoring UE velocity and adjusting the DRX period parameter accordingly (shorter periods for high velocity, longer periods for low velocity), the system optimizes both timing synchronization reliability and power-saving efficiency for different mobility scenarios.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the DRX period is extended to maximize power-saving, then energy consumption is reduced, but the UE may lose uplink timing after long sleeping periods due to UE mobility

Engineering Contradiction:
Improvepower-savingVSAvoiduplink timing synchronization
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts the DRX period based on real-time UE velocity measurements. When UE velocity is low, longer DRX periods are permitted, maximizing power-saving. When UE velocity increases, the system switches to shorter DRX periods to maintain timing synchronization, thus resolving the contradiction adaptively.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by monitoring UE velocity and using this information to adjust the DRX period. The network device receives velocity information from the UE and responds by configuring appropriate DRX parameters, creating a closed-loop system that maintains timing synchronization while optimizing power-saving based on actual mobility conditions.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If a fixed UL timing update rate of 2 Hz is used to cover the fastest UE speed of 350 km/h, then timing accuracy is maintained for high-speed UEs, but power-saving is disadvantageously limited for UEs moving at much lower speeds

Engineering Contradiction:
Improvetiming accuracyVSAvoidpower-saving
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by tailoring the DRX period to the specific mobility characteristics of each UE. Instead of using a uniform timing update rate for all UEs, the system configures appropriate DRX periods based on individual UE velocity measurements, allowing low-speed UEs to benefit from longer sleep periods while high-speed UEs maintain frequent updates for timing accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the DRX period parameter based on UE velocity conditions. By monitoring UE velocity and adjusting the DRX period parameter accordingly (shorter periods for high velocity, longer periods for low velocity), the system optimizes both timing synchronization reliability and power-saving efficiency for different mobility scenarios.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2158779B1Discontinuous reception in a mobile radio communications network
Publication Date: 2019.08.07 NEC CORP
  • EP2158779B1 patent drawingFigure 1~2
  • EP2158779B1 patent drawingFigure 3
  • EP2158779B1 patent drawing

AI summary

The invention provides for a method of controlling discontinuous reception between a mobile radio communications network device and a mobile radio communications device within a mobile radio communications network and including the step of controlling magnitude of the discontinuous reception period in a manner responsive to the velocity of movement of the mobile radio communications device within the network such that a decrease in velocity can lead to an increase in the discontinuous reception period employed by the devices.