Wireless Sensor Network Protocol Using Idle Beacons for Power Reduction

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Solution Overview

Problem

Existing wireless sensor networks face challenges in minimizing power consumption, particularly due to inefficient communications protocols that require frequent and energy-intensive network scanning, and rely on complex hardware for signal strength measurements.

Innovation Solution

A communications protocol that combines frequency channelization and time-slotted channel access, using idle beacons to reduce unnecessary scanning and allow nodes to determine the minimum power level for transmission, enabling nodes to scavenge energy from environmental sources like vibration and ambient light, and circulating headnode responsibilities among nodes to optimize energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If nodes perform frequent network scanning to discover available communication possibilities, then network adaptability and connectivity are improved, but power consumption increases significantly

Engineering Contradiction:

Improvenetwork adaptabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

Headnodes transmit idle beacons in advance during their active periods to announce upcoming active periods and provide timing information. This preliminary action allows scanning nodes to perform shorter, more efficient scans by knowing when the next active period occurs, reducing the overall network scanning time and power consumption while maintaining network adaptability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protocol implements periodic active periods followed by idle periods, with headnodes transmitting beacons at the beginning of active periods. This periodic structure creates predictable communication patterns that allow nodes to synchronize their scanning activities, reducing the total scanning time required and consequently lowering power consumption while maintaining network responsiveness.

Inventive Principle:

Principle #19Periodic action

2Reliability

If nodes use complex hardware for signal strength measurements to determine transmission power, then communication reliability is improved, but device complexity increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidhardware complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Each node uses its own received signal strength measurements of idle beacons to automatically determine the minimum transmission power level needed for reliable communication with neighboring nodes. This self-service approach eliminates the need for complex external measurement hardware, as nodes leverage their existing receivers and processors to perform power level determination through simple signal strength detection.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Nodes continuously measure the signal strength of received idle beacons and use this feedback information to adjust their transmission power levels. This feedback mechanism allows nodes to adapt their communication power dynamically based on actual channel conditions, maintaining communication reliability without requiring complex hardware, as the adjustment is performed through software-based power control.

Inventive Principle:

Principle #23Feedback

3Reliability

If headnodes transmit beacons frequently to maintain network information, then network connectivity is improved, but energy consumption increases

Engineering Contradiction:

Improvenetwork connectivityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

Headnodes transmit beacons periodically at the beginning of their active periods rather than continuously. This periodic transmission pattern maintains network connectivity information availability while significantly reducing energy consumption, as beacons are only transmitted during brief active windows rather than continuously throughout the entire cycle.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The protocol transmits beacons multiple times during active periods (excessive action) to ensure reliable reception by scanning nodes, but only during the necessary active periods rather than continuously. This partial application of excessive transmission ensures connectivity is maintained without the full energy cost of continuous beaconing.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7830838B2Energy efficient wireless sensor network, node devices for the same and a method for arranging communications in a wireless sensor network

Publication Date: 2010.11.09 WIREPAS OY

AI summary

A wireless sensor network, a node device thereof and a method for arranging communications therein are presented. A first frequency is used in wireless communication of information between a headnode and subnodes of a first cluster (103) using a time slotted channel access scheme. A headnode of a second cluster (113) known the first frequency and selects a second, different frequency for use in wireless communication of information within said second cluster (113) using a time slotted channel access scheme. The headnode of the first cluster (103) is informed about the second frequency selected for the second cluster (113). Information from the headnode of said first cluster (103) to the headnode of said second cluster (113) is communicated on said second frequency, using the same time slotted channel access scheme as other nodes in said second cluster (113).