Energy consumption study of a WSN using 6TiSCH architecture

Institut Mines-Télécom

P805 – Energy consumption study

of a Wireless Sensor Network

Cristina LUCACI

Federico SISMONDI

Wi6LABS :

Ludovic CHARPENTIER

Julien SAINT-MARTIN

Tutors :

Géraldine TEXIER

Tanguy KERDONCUFF


Agenda

WSN application

Introduction to 6TiSCH architecture and OpenWSN project

Measuring methodology

Tests: presentation, measurements and analysis

Conclusion

18/03/2015 Consumption study - 6tisch architecture 2


WSN example

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Source: http://www.cs.iit.edu/~winet/images/projects/greenObs-logo.jpg

Source http://www.libelium.com/wireless_sensor_networks_to_detec_forest_fires/


WSN application


Temp Sensor

Temp Sensor

S S

S

Lumin. Sensor

Heating

Automated blind

Root

Automated blind

Automated blind

Lumin. Sensor

SS

SS SS


Lower layers problems in WSN

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Source: IETF 6TiSCH, a New Standardization Effort to Combine IPv6 Connectivity with Industrial Performance, Xavier Vilajosana, UC Berkeley

Limiting factors:

Interference in the wireless medium

Half-duplex transceivers on the sensor

nodes


IEEE 802.15.4e TSCH

Time Slotted Channel Hopping


Source: IETF 6TiSCH, a New Standardization Effort to Combine IPv6 Connectivity with Industrial Performance, Xavier Vilajosana, UC Berkeley

Channel hopping mitigates:

Multipath fading

External interference


6 TiSCH architecture


Source 2: T.Watteyne, X.Vilajosana : OpenWSN: A standards-Based Low-Power Wireless Devepment Environment

Source1: IETF 6TiSCH, a New Standardization Effort to Combine IPv6 Connectivity with Industrial Performance

Xavier Vilajosana, UC Berkeley


OpenWSN and hardware used

Open source project developed by University of Berkeley

Provides the full stack for the 6TiSCH architecture

Provides the following tools :

• Firmware for the mote TelosB

• A web interface for monitoring and interacting with the network

Hardware: Motes TelosB

• Low-power MCU

• Energy capacity around 2500 mAh


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Which tasks and which mechanisms implemented are the most expensive in terms of energy consumption.

Which parameters of the communications stack will affect the energy consumption.

Implementation of TESTs: Allows us to test the framework OPENWSN and 6TiSCH mechanisms

Determine how the 6tisch architecture performs energy-wise in OPENWSN implementation

Objectives of Project




Radio ON Radio OFF

MCU

On Tradio (TRx+TTx) TMCU

MCU

Idle n/a Tsleep


Tests

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• Default OpenWSN implementation

• Purpose:

• Validate the measurement methodology

• Familiarize with the OpenWSN implementation

• Obtaining an approximate energy consumption

Test 1

• Default OpenWSN implementation + UDP traffic

• Purpose

• Defining an UDP application to have data messages on the network Test 2

• Tree topology +Specific schedule + UDP application

• Purpose:

• Forcing a specific topology

• Implementing an optimal schedule

Test 3

• Tree topology +Specific schedule + UDP application

• Purpose:

• Implementing a realistic scenario

• Schedule generated with optimizing communication paths tool

• Obtaining a new estimation of the energy consumption

Test 4

Institut Mines-Télécom 18/03/2015 P805 - Energy consumption study of a WSN 13

Test 1

Topology

Routing tree Traffic Specifications

• No data messages

• Only RPL messages

• Communications over one frequency

Schedule

• 11 slots in the frameslot

• 15 ms each slot

• 1 advertisment slot

• 5 shared slots

Measurement Observations

• Battery life of the acquisition mote < 1 month


Traffic Specifications

•No data messages

•Only RPL messages

•Communications over one frequency


Test 1

Topology


Test 4

Topology

Routing tree Traffic Specifications

UDP Application

• Each mote sends an UDP packet to the sink, each 10 s.

• Two frequency channels.

Schedule

Observations


Test 4

Topology


Time management


State of the art.

Theoretical study of consumption.

Definition of tests.

Modification of the code for

• Forcing topology:

─ Poisoning of neighbor tables

─ Forcing Rank of motes

• Hardcoding schedules in motes.

• Implementation of UDP applications.

• A lot of debugging time.

Measurements.

Analysis

Problems faced:

• Study the whole implementation of OPENWSN firmware.

• Rolling release problems.

Total time: 280hs


Conclusion


Project purpose: analyze 6TiSCH architecture energywise, based on OpenWSN’s

implementation.

Radio activity: main consumer in our scenarios.

Schedule implementation: significant impact on mote’s battery life.

Schedule optimization:

• can be adjusted to long and sparsed frameslots

• mote will get to sleep more and have less radio activity.

Schedule size: trade off between throughput, latency and power consumption.

No PCE entity: need of managing slots manually, to optimize the schedule for each

application in particular.


Conclusion and future work


In the following stages of this project we intended to experiment

more with the parameters

• Frameslot size

• Slot duration

• Structure of schedules

• Larger scale topology

• Different traffic load

Guarantee life battery expectancy of one year (in the lower levels of

the RPL DODAG).

Due to the lack of time, bugs and other problems encountered we

couldn’t achieve this last stage, but we are certain of its feasibility.


Thank you for your attention !


Institut Mines-Télécom 29 18/03/2015 P805 - Energy consumption study of a WSN

The protocol stack

Source: T.Watteyne, X.Vilajosana : OpenWSN: A standards-Based Low-Power Wireless Devepment Environment


Star topology



Mesh topology



First measurements


-Frame slot -FSM

-Radio on -Energy consumption

5ms


Theoretical consumption of the mote


Source: Datasheet: Mote iv Telos (Ultra low power IEEE 802.15.4 compliant wireless sensor module Revision B :

Humidity, Light, and Temperature sensors with USB)

Typical Operating Conditions nom max unit

Current Consumption: MCU on, Radio RX 21,8 23 mA

Current Consumption: MCU on, Radio TX 19,5 21 mA

Current Consumption: MCU on, Radio off 1800 2400 uA

Current Consumption: MCU idle, Radio off 54,5 1200 uA

Current Consumption: MCU standby 5,1 21 uA


The time chart of a simple Tx/Rx Scenario


Source: https://openwsn.atlassian.net/wiki/display/OW/IEEE802.15.4e

Energy consumption study of a WSN using 6TiSCH architecture

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