Dash7 and 433
Transcript of Dash7 and 433
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Why Does DASH7 Use 433 MHz?JP Norair
Why Does DASH7 Use 433 MHz?
Co-chair, DASH7 Technology Working Group18 September 2009
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www.dash7.orgDASH7 Confidential
Ultra-low Energy
What isWireless Data Technology
Based on the ISO 18000-7 standardWhat is
DASH7?standardMandated by U.S. Department of Defense, allied militariesTypical range: 250 m (up to 5 km)433 MHz
DASH7 i t ISO 18000 7 28 kbpsExtendable to 2-hop (ad hoc), sensor, security, and other
DASH7 is to ISO 18000-7
what WiFi is to IEEE sensor, security, and other features802.11
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Why does DASH7use 433 MHz ?
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THERE ARE DASH7 Confidential
~1 MHz AM Radio
~100 MHz FM RadioMANY
FREQUENCIES ~100 MHz FM Radio433 MHz DASH7
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FREQUENCIES AVAILABLE
900 MHz 2G/3G Cellular
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Each frequency band has its own strengths and weaknesses Low 2 GHz US 3G Cellular
2.45 GHz WiFi, Bluetooth
strengths and weaknesses. Low-power, two-way communication
typically can only be done in one of the bands to the leftthe bands to the left.
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www.dash7.orgDASH7 Confidential
433 MHz DASH7
900 MHz 2G/3G Cellular900 MHz 2G/3G Cellular
2.45 GHz WiFi, Bluetooth
Of these bands, there are only three can be used in most countries without paying the local government for a license.
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433 MHz DASH7
2.45 GHz WiFi, Bluetooth
And only two that can be used internationallywithout a license
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1 GHz 2 GHz 3 GHz
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ApplicationsRadio US
3G
Bluetooth
WiFiDASH7
GSMpp
ZigBeeHDTV HDTV
Long Range High Data Rate
Attributes Low NoiseNon-Line-of-Sight
Many Channels
High Interference
WHICH FREQUENCY IS BEST?Each frequency has basic advantages and disadvantages. Higher frequencies sacrifice most attributes in order to deliver larger bandwidths and higher data rates.
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HOW DOES
DASH7 Confidential
HOW DOES DASH7DASH7
STACK UP?Different technologies utilize their frequency bands in different ways
(the basic attributes still apply).( y)Communications engineers can turn
weaknesses into strengths, at the cost of added complexity or other
tradeoffs.
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2.45 GHz
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433 MHz High Data Rate Multiple Channels Streaming Video
High Power Short Range Easily Interfered
2.45 GHz Medium Data Rate Frequency
Hopping
Very Short Range Poor Coverage Medium Power
Long Range Penetrates Concrete
(Great Coverage) Ultra Low Power
2.45 GHz
g Streaming Audio
Low Power Easily Interfered
U a o o e Low Interference
Low Data Rata Some Antenna Low Power Easily Interfered
Poor Coverage Short Range
Limitations
A technology should be used in applications that maximize its strengths.Technologies without strengths will struggle even if they have no weaknesses.