Technical Presentation of the 433 MHz based, low power DASH7 Alliance Protocol

1. Dash7 Alliance Protocol

2. ISO/IEC 18000-7
The Dash7 Alliance Protocol is based on the ISO/IEC 18000-7
ISO/IEC 18000 is an international standard that describes a series
of diverse RFID technologies, each utilizing a unique frequency
range.
ISO/IEC 18000-7 describes the parameters for active air interface
communications at 433 MHz (2008 - 2009)
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3. DASH7 Alliance Protocol
Active RFID Standard for 433 MHz.
•
•
•
•
Build on top of asynchronous WSN MAC.
High level functionality optimized for RFID.
Defines full functional RFID tag.
Can be extended to non RFID applications.
Supports Tag to Tag communication.
DASH7 Alliance Protocol is designed to support fixed and mobile nodes
that need to upload or retrieve small chunks of information
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4. History
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5. OSI Model
ZigBee
WirelessHart
ISA100.11a
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Protocol
IEEE 802.15.4
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6. Wireless Available Solutions
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7. Technology Comparison
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8. Node Types
Transmit
Receive
Complete
Feature set
Blinker
X
X
Subcontroller
X
X
X
Gateway
X
X
X
Always-on
Receive
X
Endpoint
Wake-on
Scan Cycle
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X
X
X
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9. Spectrum and Modulation
Dash 7 band: 433.056 Mhz - 434.784 Mhz
• Modulation GFSK
• 8 non overlapping normal rate channels (55 kbs)
• 7 hi-rate channels (4 non overlapping) (200 kbs)
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10. DASH7 band available worldwide
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11. 433MHz band regulations
Unlicensed ISM/SRD bands
USA/Canada
• 260-470 MHz (FCC Part 15.231; 15.205)
Europe:
• 433.050 - 434.790 MHz (ETSI EN 300 220)
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12. Frequency vs Range
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13. Network Topology
Star
Tree
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Mesh
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14. Passive RFID
Tags can only be read in the immediate proximity of a reader
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15. Active RFID
Longer range interrogators - Master/Slave
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16. Mesh WSN
Range depends on number of router nodes
Congestion - Routing complexity
Latency due to propagation through the network
Routers need to be powered and add to the overall consumption of the system
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17. DASH7
Range of Gateway can be extended by subcontrollers
Simple routing (2 hops)
Subcontrollers need to be powered but only a few are needed
Tag-2-Tag communication
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18. BLAST networking technology
Bursty: Data transfer is abrupt and does not include content such as video, audio, or
other isochronous forms of data
Light: For most applications, packet sizes are limited to 256 bytes. Transmission of
multiple, consecutive packets may occur but is generally avoided if possible.
Asynchronous: DASH7's main method of communication is by command-response,
which by design requires no periodic network "hand-shaking" or synchronization
between devices.
Stealth: DASH7 does not use discovery beacons, end nodes can chose to respond
only to pre-approved devices.
Transitive: A DASH7 system of devices is inherently mobile or transitional. Unlike
other wireless technologies DASH7 is upload-centric, not download-centric, thus
devices do not need to be managed extensively by fixed infrastructure (i.e. base
stations) to respond only to pre-approved devices.
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19. Communication Model
Pull
Push
To obtain spontaneous data
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For alarms and periodic data
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20. Asynchronous communication
DASH7 supports asynchronous communication using the
advertisement protocol
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21. Query
Query based addressing by
data content (id, sensor values,
location, metadata, …)
In contrast to address based
addressing in other technologies.
I want to know all nodes with a
temperature above 15°C
All nodes respond with your
temperature.
I want to know all the person
tags within proximity of the
LivingRoomNode.
All nodes with subnet X send me
your RSSI.
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22. Global & Local Querying
Global addressing enables the
notification of a big group that a
query will shortly follow and then
selectively query a local group.
1. Ad-hoc synchronization is
used to notify all endnodes of
coming query.
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23. Global & Local Querying
1. Ad-hoc synchronization is
used to notify all endnodes of
coming query.
2. Global query activates all
endnodes with temperature
sensor. Others go in sleep
mode (red).
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24. Global & Local Querying
1. Ad-hoc synchronization is
used to notify all endnodes of
coming query.
2. Global query activates all
endnodes with temperature
sensor. Others go in sleep
mode (red).
3. Local query asks response of
all endnodes with T > 25°
(yellow). Other go in sleep
mode till next local query
period (orange).
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25. Global & Local Querying
1. Ad-hoc synchronization is
used to notify all endnodes of
coming query.
2. Global query activates all
endnodes with temperature
sensor. Others go in sleep
mode (red).
3. Local query asks response of
all endnodes with T > 25°
(yellow). Other go in sleep
mode till next local query
period (orange).
4. Next local query for endnodes
with T < 25° and T >10°
(yellow). Remaining go in
short sleep mode (orange).
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26. Global & Local Querying
1. Ad-hoc synchronization is
used to notify all endnodes of
coming query.
2. Global query activates all
endnodes with temperature
sensor. Others go in sleep
mode (red).
3. Local query asks response of
all endnodes with T > 25°
(yellow). Other go in sleep
mode till next local query
period (orange).
4. Next local query for endnodes
with T < 25° and T >10°
(yellow). Remaining go in
short sleep mode (orange).
5. Remaining nodes are queried.
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27. Tag to Tag communication
At any time an endnode can communicate to another endnode.
E.g. Proximity based events can trigger communication
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28. Low
Cost
Low
Bitrate
Long
Range
Large
Number
Of Nodes
Very
Low
Power
Open
Standard
Security
Privacy
www.dash7.org
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