DASH7 Context aware sensor and actuator data propagation system using sub-1 Ghz

Prof. Maarten Weyn 17th Work Meeting – Wireless Connectivity for the Internet of Things

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ORIGIN The Dash7 Alliance Protocol originates from ISO/IEC 18000-7

ISO/IEC 18000 is an international standard describing diverse RFID technologies, each utilizing a unique frequency range.

ISO/IEC 18000-7 (”dash 7” ) describes the parameters for active air interface communications at 433 MHz (2008 - 2009)

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The DASH7 Alliance (D7A) enhanced ISO 18000-7 for Ultra Low Power, Mid-Range Wireless Sensor Communication.

The DASH7 Alliance is working on the expansion of the air interface to all sub-GHZ ISM/SRD bands.

OPEN WIRELESS SENSOR

COMMUNICATION STANDARD

history

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CoSys-Lab and DASH7 Alliance

CoSys-Lab / UAntwerpen • Active in DASH7 Alliance meetings starting from 2011 • Developing Open Source Stack • Developed different DASH7 hardware prototypes • M. Weyn, G. Ergeerts, D. Subotic Maarten Weyn • Board of Directors (Secretary) from 2013 • Chair of University Action Group • Active in Protocol Action Group

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BLAST networking technology

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Data transfer is abrupt and does not include content such as video, audio, or other isochronous forms of data For most applications, packet sizes are limited to 256 bytes. DASH7's main method of communication is by command-response, which by design requires no periodic network "hand-shaking" or synchronization between devices. DASH7 does not use discovery beacons, end nodes can chose to respond only to pre-approved devices. A DASH7 system of devices is inherently mobile or transitional.

BURSTY LIGHT ASYNC STEALTH TRANSITIONAL

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USE CASE

Collection of humidity sensor data

SENSOR DATA

SOLUTION 1: application implements communication

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Application periodically measures humidity and sends data to the gateway.

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Application periodically measures humidity and writes value to the file system

SOLUTION 2: use file notifications

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DASH7 detects file change Notification file is enabled

DASH7 checks query

DASH7 sends notification

SOLUTION 2: use file notifications

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Application periodically measures humidity and writes value to the file system

SOLUTION 3: request - response

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Gateway wakes up nodes using AdvP

Gateway requests file content in query

Nodes respond with data

SOLUTION 3: request - response

Context Aware Sensor and Actuator Data Propagation

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Write and read to/from files Configure system through configuration files

Configured through file system Handles scheduled scan cycles Handles queries from other devices Handles queries and notifications on file changes File system configurable over the air

Technology Comparison

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Distance – Complexity – Energy – Latency

Tree Mesh Star

Passive RFID Tags can only be read in the intermediate proximity of a reader

Active RFID Longer range interrogators – Master/Slave

DASH7 Simple routing (2 hops) subcontrollers are power but only few are needed Tag-to-Tag & Tag-Talk-First

Mesh Range depends on number of router nodes Congestion – Routing Complexity – Latency Routers need to be powered Each hop consumes energy

Passive RFID

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Active RFID

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Mesh WSN

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DASH7 18

Frequency vs Range

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Spectrum and Modulation

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ISM/SDR 433: 433.056 Mhz - 434.784 Mhz • 2-GFSK Modulation • 8 non overlapping normal rate channels (55 kbs) • 7 hi-rate channels (4 non overlapping) (200 kbs) • Proposal for 72 low rate channels (9.6 kbs)

EU: ISM 868: 868.000 – 870 Mhz USA: ISM 902 – 928 Mhz

• Long range

• Low Power

• Hardware provider independent

• Mobile communication

• Full stack specified

• Dynamic pull/push

• Low Power wakeup

• Asynchronous

• Open source stack

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• Low datarate

• Low Power

• Antenna design

• Full stack specified

• Asynchronous

• Open source stack

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POWER BUDGET

Application Driven:

E.g.: 1 year on coin cell (200 mAh)

E.g.: “the lifetime of the bird and weight ≤ 1 gram”

E.g.: 2 years on ½ AA 3.6V battery 1100 mAh 62 µAh/day

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Low Power?

LG Nexus 5: 2300 mAh / day?!!!

Raspberry pi: 500 mAh

TelosB

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Presence Detection

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Open Source Stack for DASH7

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http://oss-7.cosys.be

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Open Source Stack for DASH7

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www.dash7-alliance.org maarten.weyn@uantwerpen.be

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Open Standard

Very Low

Power

Security Privacy

Large Number Of Nodes

Low Bitrate

Low Cost

Long

Range