DRX Timer Control for Wireless Network Battery Optimization

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Solution Overview

Problem

Current discontinuous reception (DRX) technologies in LTE_ACTIVE state face challenges such as inefficient signaling, missed handover opportunities, and timer configuration issues, which affect battery life and network resource utilization.

Innovation Solution

Implementing a method to control a short DRX timer, prevent retransmission timer start, and adjust DRX periods using a MAC-PDU header with optional fields for DRX activation/deactivation, and utilizing a DRX MAC control element to manage DRX cycles, allowing for efficient transition to long DRX periods without explicit RRC reconfiguration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If DRX is implemented in LTE_ACTIVE state, then battery life is improved, but network resource utilization deteriorates due to missed handover opportunities and inefficient signaling

Engineering Contradiction:

Improvebattery lifeVSAvoidnetwork resource utilization

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent implements dynamic DRX cycle adjustment where the UE transitions between short DRX and long DRX cycles based on network conditions and traffic patterns. The MAC entity monitors downlink data arrivals and adjusts the DRX cycle length accordingly, allowing the system to adapt between energy-saving mode (long DRX) and network-responsive mode (short DRX), thus resolving the contradiction between battery life and network resource utilization

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs preliminary actions by configuring DRX parameters and timers in advance through RRC signaling and MAC control elements. The network pre-configures shortDRX-SlotOffset, drx-HARQ-RTT-TimerDL, and other parameters before DRX operation begins, enabling the UE to proactively manage its reception schedule and avoid missed handovers while maintaining battery savings

Inventive Principle:

Principle #10Preliminary action

2Speed

If short DRX cycle is used, then network responsiveness is improved, but energy consumption increases

Engineering Contradiction:

Improvenetwork responsivenessVSAvoidenergy consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic DRX cycles with alternating short and long durations. The UE alternates between short DRX cycles (providing fast network responsiveness) and long DRX cycles (reducing energy consumption). The MAC entity transitions to long DRX after a threshold number of short DRX cycles or when downlink data becomes inactive, creating a periodic pattern that balances responsiveness and energy efficiency

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the DRX cycle length based on real-time network conditions. When downlink data arrives frequently, the UE uses short DRX cycles for rapid response. When traffic subsides, the UE transitions to long DRX cycles to conserve energy. This dynamic adaptation resolves the contradiction between network responsiveness and energy consumption

Inventive Principle:

Principle #15Dynamics

3Reliability

If DRX activation is signaled explicitly through RRC, then reliability is improved, but signaling overhead increases

Engineering Contradiction:

ImproveDRX activation reliabilityVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent introduces a MAC Control Element (MAC CE) as an intermediary for DRX activation and deactivation signaling. Instead of using only RRC signaling (which is reliable but overhead-heavy), the MAC CE provides a lightweight layer 2 mechanism for DRX control. The MAC CE contains compact fields for DRX command indication, allowing reliable DRX activation with minimal signaling overhead

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the DRX control signaling into multiple layers: RRC signaling for initial configuration (high reliability) and MAC CE for dynamic activation/deactivation (low overhead). This segmentation allows the system to use the appropriate signaling method for each function, achieving both reliability and low overhead

Inventive Principle:

Principle #1Segmentation

4Reliability

If retransmission timer is always started, then reliability is improved, but unnecessary monitoring increases energy consumption

Engineering Contradiction:

Improveretransmission reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements self-service by having the UE autonomously determine whether to start the retransmission timer based on local conditions. The MAC entity checks whether a short DRX cycle is configured and whether the current timing conditions meet the criteria for retransmission. This autonomous decision-making eliminates unnecessary timer startups during long DRX periods, reducing energy consumption while maintaining reliability when needed

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP3723420B1Method and system for the control of discontinuous reception in a wireless network

Publication Date: 2022.08.31 BLACKBERRY LTD

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AI summary

A method to control a short discontinuous reception 'DRX' timer. The method comprises: determining whether a short DRX cycle is configured; using a long DRX cycle if the short DRX cycle is not configured; determining whether a MAC control element is received, if the short DRX cycle is configured; and determining whether the short DRX timer is started, and restarting the short DRX timer associated with the short DRX cycle if the short DRX timer is running, in a case that the MAC control element is received.