Adaptive Transmit Power for D2D Battery Management

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Solution Overview

Problem

Device-to-device (D2D) communication systems face challenges in efficient power management and message transmission, particularly in emergency situations where battery life is critical and message congestion leads to resource drainage and collisions.

Innovation Solution

Implementing a method that dynamically adjusts transmit power by looping through a sequence of default and reduced power values in consecutive frames, and reducing the frequency of emergency message broadcasting based on acknowledgement messages received, along with using reduced payload ACK messages to minimize collisions and conserve battery power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a primary device continuously transmits synchronization signals and discovery messages at default power levels, then communication reliability is improved, but battery life deteriorates

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidbattery life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies periodic action by implementing frame-based transmission cycles where the primary device transmits synchronization signals and discovery messages at regular intervals rather than continuously. Each frame contains specific time slots for these transmissions, creating a periodic pattern that maintains communication reliability while allowing battery rest periods between frames, thus extending battery life.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the transmit power level variable rather than fixed. The primary device dynamically adjusts transmission power between default and reduced levels based on battery status and communication needs. This dynamic power adjustment allows the system to optimize between reliability and battery conservation in real-time operating conditions.

Inventive Principle:

Principle #15Dynamics

2Reliability

If emergency messages are broadcast frequently to ensure message delivery, then message delivery reliability is improved, but resource drainage increases

Engineering Contradiction:

Improvemessage delivery reliabilityVSAvoidresource drainage

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies feedback by implementing an acknowledgment message mechanism where secondary devices confirm receipt of emergency messages. The primary device monitors these acknowledgments and adjusts subsequent message broadcasting based on the feedback received. This feedback loop ensures reliable message delivery while avoiding redundant transmissions that would waste battery resources.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies partial action by transmitting only the essential portions of emergency messages when battery resources are constrained. Rather than continuously broadcasting complete message sets, the system transmits critical information selectively based on acknowledgment feedback and battery status, reducing resource drainage while maintaining essential message delivery reliability.

Inventive Principle:

Principle #16Partial or excessive action

3Area of stationary object

If transmit power is increased to extend communication range, then coverage area is improved, but power consumption increases

Engineering Contradiction:

Improvecoverage areaVSAvoidpower consumption

Core Design Contradiction:

Area of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by dynamically modifying the transmit power parameter based on operational conditions. The system switches between default power levels (providing extended coverage) and reduced power levels (conserving energy) according to battery status and communication requirements. This parameter adjustment allows optimization of the coverage area versus power consumption trade-off.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If ACK messages are transmitted with full payload to confirm message receipt, then acknowledgment reliability is improved, but collision probability increases

Engineering Contradiction:

Improveacknowledgment reliabilityVSAvoidmessage collision

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies extraction by removing unnecessary payload data from acknowledgment messages, retaining only the essential confirmation information. This streamlined ACK approach maintains sufficient acknowledgment reliability for emergency communication while significantly reducing the probability of message collisions by minimizing the time secondary devices spend transmitting and the amount of data in the channel.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20200100177A1Adaptive transmit power for efficient battery management

Publication Date: 2020.03.26 APPLE INC

AI summary

In a method of device-to-device communication, efficient power management is provided when a primary device has a low battery level. The primary device can send synchronization signals and discovery messages to secondary devices by looping through a sequence of transmit power values in a sequence of consecutive frames, where the sequence of transmitting values includes a default power value and a reduced power value.