Ultra WideBand

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Ultra WideBand

• Paul Solecki

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History of UWB

• 1962 Study in time-domain
  electromagnetics (Ross)
• 1968 - Short Pulse Radar and Communications
  Systems conceived
• 1973 First UWB patent issued
• 1978 Developed SPR and CS
• 1984 LPI/D developed
• 1989 DoD refers to it as UWB
• 1994 to present Most work done without
  classified government restriction

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Ultra WideBand

• Also referred to as impulse, baseband or
  zero-carrier technology
• Pulses instead of continuous waves
• Pulse length on order of sub-nanoseconds in time
  domain
• Result is that it uses a wide swath of bandwidth
  in frequency domain

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Pulse vs. Continuous Wave
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Benefits

• 100-500 Mbps rate
• Ideal for short range WPANs , lt 10m
• Virtually NO Multi-path interference
• Very low power emission
• UWB radio 75nW/GHz , .26mW aggregate
• 802.11b radio - 30 100mW
• Bluetooth radio 1mW-1W
• Shannons equation becomes linear with respect to
  Bandwidth and Power
• Simplified architecture, nearly all digital
• Small silicon space usage

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UWB Disadvantages

• Bad for gt 10 Gbps
• Due to FCC limit of power emission

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UWB - Applications

• Wireless Networks WPANs
• Wireless home systems
• Computer
• Entertainment center
• Covert communication
• Radar
• fine resolution
• Automotive
• Ground penetrating
• Streaming A/V for
• PDAs
• Digital camera
• MP3 players
• Electronic measuring devices
• Electronic positioning devices
• See through walls etc.

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UWB Standard

• IEEE 802.15.3a Task Force
• FCC set aside 7500MHz of spectrum for unlicensed
  use
• 3.1 GHz - 10.6 GHz
• 100/200/400 Mbps at 10/4/2m
• OFDM vs. DS-CDMA
• TI/Intel vs. Motorola/XtremeSpectrum
• 4.8 GHz is perceived to be the upper band due to
  current CMOS technology

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UWB

• FCC spectral mask
• UWB signals must not exceed threshold of spectral
  mask

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UWB vs. WiFi
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802.15.3a Debate

• Sept. 2003 IEEE conference results in 60
  approval for OFDM
• OFDM vs. DS-CDMA
• TI/Intel vs. Motorola/XtremeSpectrum
• 75 needed for acceptance
• Compatibility issues

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UWB-OFDM

• Multiple Bands in 3.1 GHz 4.8 GHz
• 500 MHz slices
• Interleave signals

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UWB-OFDM Advantages

• Cost
• Power consumption
• Complexity of device
• Proven in 802.11a

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UWB OFDMDisadvantages

• Interference
• Time synchronization needed

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UWB DS-CDMA

• Direct Sequence Spread Spectrum
• In a direct sequence system, the
• transmitted baseband signal is multiplied
• by a pseudonoise code digital stream.

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UWB - DS-CDMA
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UWB DS-CDMAAdvantages

• Very low interference along ENTIRE spectrum
• Avoids potential cross-border interference

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UWB DS-CDMA Disadvantages

• Complexity of device
• Power use
• Cost

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UWB vs. Competing Technologies
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UWB Bi-phase Radio system

• All Digital !!
• No Power Amplifier needed