Discontinuous Reception Control for VoIP Power Saving

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Solution Overview

Problem

Current wireless communication systems face inefficiencies in battery power consumption due to continuous monitoring for dynamic scheduling grants during VoIP sessions, which leads to reduced battery life, especially when few or no grants are received.

Innovation Solution

Combining semi-persistent scheduling for VoIP with dynamic scheduling for additional packet transmissions, allowing mobile devices to enter a discontinuous reception (DRX) mode by allocating awake and sleep periods, thus reducing power consumption by only monitoring layer 1 CCEs during awake periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous monitoring for dynamic scheduling grants is implemented during VoIP sessions, then communication reliability is improved, but battery power consumption increases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidbattery power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements discontinuous reception (DRX) where the mobile device alternates between awake periods (monitoring for grants) and sleep periods (power saving). This periodic monitoring pattern resolves the contradiction by maintaining communication reliability during awake periods while reducing battery consumption during sleep periods, allowing the device to reliably receive VoIP packets during talk-spurts without continuous monitoring.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the DRX configuration parameters (awake period duration, sleep period duration, offset values) based on traffic conditions and service requirements. This dynamic adaptation allows the device to optimize between reliability and power consumption by extending awake periods when communication reliability is critical and extending sleep periods when power saving is prioritized.

Inventive Principle:
Principle #15Dynamics

2Duration of action of moving object

If discontinuous reception mode is implemented to save battery power, then battery life is extended, but the ability to receive additional packets dynamically may be compromised

Engineering Contradiction:
Improvebattery lifeVSAvoidability to receive additional packets
Core Design Contradiction:
Duration of action of moving objectVSAdaptability or versatility

Solution Approach 1:

The network pre-configures DRX parameters including awake period durations and offsets before the mobile device enters DRX mode. This preliminary configuration ensures that the device has predetermined windows to monitor for both VoIP packets and additional dynamic packets, allowing battery saving while maintaining the ability to receive various packet types during configured awake periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The DRX awake periods are designed to serve multiple functions: receiving VoIP packets during talk-spurts, receiving additional dynamic packets (such as RTCP, SIP/SDP, or RRC signaling), and allowing the device to remain in power-saving mode otherwise. This multi-functionality resolves the contradiction by making the same awake periods useful for various communication needs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If semi-persistent scheduling is used for VoIP traffic, then signaling overhead is reduced, but flexibility to handle additional packet types is limited

Engineering Contradiction:
Improvesignaling overheadVSAvoidflexibility to handle additional packet types
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent merges semi-persistent scheduling (for regular VoIP traffic) with dynamic scheduling (for additional packet types) within the same DRX framework. The mobile device uses semi-persistent resources during awake periods for VoIP packets while also monitoring for dynamic grants during the same awake periods for additional packets. This combination resolves the contradiction by maintaining the low signaling overhead of semi-persistent scheduling while adding the flexibility of dynamic scheduling through shared DRX resources.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2413638B1System and method for discontinuous reception control start time
Publication Date: 2015.10.07 BLACKBERRY LTD
  • EP2413638B1 patent drawingFigure 1~2
  • EP2413638B1 patent drawingFigure 3~4
  • EP2413638B1 patent drawingFigure 5

AI summary

Methods of combining semi-persistent resource allocation and dynamic resource allocation are provided. Packets, such as VoIP packets, are transmitted on the uplink and downlink using respective semi-persistent resources. For each mobile device, awake periods and sleep periods are defined. The semi-persistent resources are aligned with the awake periods so that most of the time the mobile device can turn off its wireless access radio during the sleep periods. In addition, signalling to request, and to allocate, resources for additional packets are transmitted during the awake periods, and the resources allocated for the additional packets are within the awake periods. Methods of extending the awake periods in various embodiments are also provided. Methods of determining the first on period are also provided.