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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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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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

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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

DASH7 Confidential

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.