Ultra Wide Band UWB Technology

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Ultra Wide Band (UWB) Technology Its
Applications
by Dr.A.T.Kalghatgi
Chief Scientist Central Research
Laboratory Bharat Electronics Limited., Bangalore
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Overview

• Trends that drive short range wireless
• Definition of UWB
• Advantages of UWB
• Applications of UWB
• UWB Challenges

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Trends that are driving short-range wireless

• The growing demand for wireless data capability
  in portable devices at higher bandwidth
• Crowding in the spectrum that is segmented and
  licensed by regulatory authorities in traditional
  ways.
• The growth of high-speed wired access to the
  Internet in enterprises, homes, and public
  spaces.
• Shrinking semiconductor cost and power
  consumption for signal processing.

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Communication using Pulse
Sinusoidal signals are narrow in frequency and
"wide" over time
A pulse is narrow in time and wideband in
frequency
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Narrow band Problems
Narrowband Problems Multipath
fading -Destructive interference of CW signals
causes signal loss Insecure -Narrow Band
signals are easily detected and jammed Poor
range resolution-Range resolution for tracking
applications is a function of RF bandwidth
Limited data rate -Narrow RF bandwidth means
narrow data bandwidth
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The UWB solution

• Ultimate in spectrum spreading
• GHz of RF bandwidth
• Has all the advantages of spread spectrum
• But to a much larger extent
• Immune to multipath fading
• Virtually undetectable
• Unprecedented range resolution
• Potential for very high data rates
• Simple to implement
• High capacity

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Comparison of UWB vs Spread Spectrum and Narrow
Band
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Definition of UWB

• Conventional Definition- Short Pulse
• Carrier Free,Baseband or Impulse based
• Typically only a Free RF Cycles
• - Large fractional bandwidth (BW/f)
• Very low duty cycles resulting in low average
  energy densities
• Typically generated by impulse or step excited
  antennas and filters

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UWB Pulse Waveforms
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UWB Fractional Bandwidth
As per FCC guidelines UWB fractional bandwidth is
defined by,
Where fu upper 10 dB point fl lower 10 dB
point   Either 25 fractional bandwidth criteria
should be met or the instantaneous bandwidth of
500 MHz.
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Multi Band OFDM
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FCC Emission Requirements
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Comparison of occupied bandwidths by UWB and
other wireless technologies
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Comparison of Spatial Capacity
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Comparison of Spatial Capacity of Various Indoor
Wireless System
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Comparison of UWB bit rate with other wired and
wireless standards
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UWB Major Application Areas
a) Communications Wireless Audio, Data Video
Distribution RF Tagging Identification b)
Radar Collision/Obstacle Avoidance Precision
Altimetry Intrusion Detection (see through
wall) Ground Penetrating Radar c) Precision
Geolocation Asset Tracking Personnel
localization
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Some of Military Commercial Applications of UWB
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SourceMSSI
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Voice and Data Communications

• With increasing congestion in the radio spectrum
  from communications appliances of all forms, new
  schemes for allowing more users in a given area
  are always sought.

• UWB allows users to simultaneously share the
  spectrum with no interference to one another and
  to apply it in UWB devices, such as high-speed
  home and business networking devices as well as
  storage tank measurement.

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 Ground and Ice Penetrating RADAR

•   A system used to detect objects buried in the
  ground.
• A special directional antenna to transmit the
  stimulus signal into the ground and receive the
  reflected waves.
• Depth of penetration is typically between 0.5 and
  10 m, very short pulses are needed to resolve
  typical buried targets.

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Wall Imaging Radar System

• To detect the location of objects contained
  within a "wall," such as a concrete structure,
  the side of a bridge, or the wall of a mine.
• Operation is restricted by FCC to law
  enforcement, fire and rescue organizations, to
  scientific research institutions, to commercial
  mining companies, and to construction companies.

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Through Wall Radar System

• Uses very short pulses to provide detection of
  objects on the opposite side of a non-metallic
  wall.
• The stimulus signal is transmitted into the wall.
  A portion of the signal incident on the wall is
  transmitted through the wall and into the space
  on the far side.

• Objects in the field then reflect the signal back
  to the wall where part of the signal is
  transmitted through the wall to the receiver.
• Freq of Operation below 960 MHz or 3.1-10.6 GHz
  band.

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Surveillance Systems

• UWB based Surveillance systems operate as
  "security fences" by establishing a stationary RF
  perimeter field ("bubble") and detecting the
  intrusion of persons or objects in that field.

• "Bubble" can be established to cover either
  certain area or certain object, such as aircraft,
  vehicle etc.
• Frequency band 1.99-10.6 GHz.

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Vehicular Radar Systems

• Potential applications include
• collision avoidance,
• proximity aids,
• intelligent cruise control systems,
• improved airbag activation
• suspension systems that better respond to road
  conditions.
• FCC limits operation of vehicular radar to the
  22-29 GHz band using directional antennas on
  terrestrial transportation vehicles provided the
  center frequency of the emission and the
  frequency at which the highest radiated emission
  occurs are greater than 24.075 GHz.

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Fluid Level Measurements
UWB distance measuring hardware can be used as
an electronic dipstick, to determine the level of
a fluid in a tank by measuring the distance
between the top of the tank and the interface
with the surface of the fluid.   
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Asset Location

• Another form of data communications.
• Up-to-date inventory of assets in a given
  location.
• A coded transmitter can be attached to each
  asset for instantaneous inventory control.
• Not only can determine the presence of a
  particular object, but also provides information
  as to its exact location.

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ID Tags

• Similar to asset tracking, ID tags can be used to
  wirelessly identify individuals with issued ID
  tags.
• Other applications are Intelligent Transportation
  Systems, Electronic Signs and Smart Appliances

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UWB can enable a wide variety of WPAN
applications.

• Replacing IEEE1394 cables between portable
  multimedia CE devices, such as camcorders,
  digital cameras, and portable MP3 players, with
  wireless connectivity
• Enabling high-speed wireless universal serial
  bus (WUSB) connectivity for PCs and PC
  peripherals, including printers,scanners, and
  external storage devices
• Replacing cables in next-generation Bluetooth
  Technology devices, such as 3G cell phones, as
  well as IP/UPnP-based connectivity for the next
  generation of IP-based PC/CE/mobile devices
• Creating ad-hoc high-bit-rate wireless
  connectivity for CE,PC, and mobile devices

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PC Clusters interconnected thru UWB enabled
Wireless USB
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UWB Key Design Challenges

• Co-existence with other services Strong narrow
  band interference
• Shaping of spectrum of the TX signal (impulse
  radio, multi-band OFDM based UWB etc.)
• Practical and Simple Receiver Design
  (Synchronisation/Coherent or non coherent
  receiver design)
• Wideband RF components (antenna,LNA etc.)
• Time Domain response of antenna is important
  since the antenna shapes the pulse
• Antennas for impulse radio can no longer be
  optimized at the carrier frequency
• Flat group delay so that high and low frequency
  signals arrive simultaneously
• High Sampling rate ADCs for digital
  implementations

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Other Challenges for UWB

• For UWB technology to become a widely adopted
  radio solution, a few key areas need to be
  resolved
• Performance (including over-the-air data rate
  performance, power consumption, co-existence with
  other wireless devices, immunity to interference,
  and link robustness)
• Interoperability
• Time-to-market considerations
• Ease of product integration and certification
• Overall solution cost (to the OEM)
• Fulfillment and support
• Quality of service
• Global spectrum allocation

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Thank You