new technology based on wireless system

1. By
S.PRANEETH KUMAR
EIE Dept
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2. Outline
• Introduction
• What can Wi-Vi do?
• Design Methodology
• Applications
• Advantages
• Limitations
• Results
• Conclusion
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3. Through Wall RADAR
• Eliminate “Flash Effect” by isolating signals reflected off
the wall from the signals reflected off the objects behind
the wall.
• Isolation can be achieved in Time or Frequency domain
which requires UWB (Ultra-Wideband Widths) of the
order of 2GHz.
• Difficult to capture the reflections.
• Narrowband RADARs use Doppler Shift to detect moving
objects behind the wall but can be done only in free space
with no obstruction or with low attenuation standing wall 3

4. Wi-Vi
• Wi-Vi stands for Wi-Fi Vision.
• Demonstrated by Dina Katabi, a professor in MIT’s
Department of Electrical Engineering and Computer
Science, and her graduate student Fadel Adib.
• Wi-Vi uses Wi-Fi OFDM signals in the ISM band and typical
Wi-Fi hardware.
• Wi-Vi limits itself to a 20 MHz-wide Wi-Fi channel, and
avoids ultra-wide band solutions used to address the
flash effect.
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5. • Wi-Vi is essentially a 3-antenna MIMO device: two of the
antennas are used for transmitting and one is used for
receiving.
• It also employs directional antennas to focus the energy
toward the wall or room.
• It is relatively a low-power, low-cost, low-bandwidth, and
accessible to average users.
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6. What can Wi-Vi Do?
• Detect the Number of Moving Humans in a Closed Room.
• Determine the Relative Locations of Moving Humans.
• Enable Communication through a Wall without Carrying a
Wireless Device.
• Identify Simple Gestures from Behind a Wall.

7. • Transmit two waves that cancel each other when they
reflect off the Static object but not the Moving object.
Wall is Static Disappears
People tend Detactable
to move
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8. Wi-Vi Setup
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9. ISAR
Direction of
reflection
Direction of
motion
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11. Applications
Police avoids ambush Firefighters check for humans
Personal Security Gesture Interface from behind a
wall
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12. Advantages
• Wi-Vi requires only few MHz of bandwidth and operates in
the same range as Wi-Fi. It operates in ISM band.
• Wi-Vi can perform through-wall imaging without access to
any device on the other side of the wall.
• Wi-Vi employs signals whose wavelengths are 12.5 cm.
• Extend human vision beyond the visible electromagnetic
range, allowing us to detect objects in the dark or in smoke.
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13. Limitations
• Display has very low resolution.
• We cannot detect humans behind concrete walls thicker than
8".
• To achieve a narrow beam the human needs to move by
about 4 wavelengths (i.e., about 50 cm).
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14. Future Scope
• Wi-Vi could be built into a Smartphone or a special
handheld device.
• Can be used in search-and-rescue missions and law
enforcement
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15. Results
• A prototype of Wi-Vi using USRP N210 radios software was
implemented and evaluated in two office buildings by Fadel Adib and
Dina Katabi, Massachusetts Institute of Technology (MIT), Results
are as follows:
• Wi-Vi can detect objects and humans moving behind opaque
structural obstructions. This applies to 8" concrete walls, 6"
hollow walls, and 1.75" solid wooden doors.
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16. Conclusion
Wi-Vi, a wireless technology that uses Wi-Fi signals to detect
moving humans behind walls and in closed rooms. In contrast to
previous systems, which are targeted for the military, Wi-Vi enables
small cheap see-through-wall devices that operate in the ISM band,
rendering them feasible to the general public, without carrying any
transmitting device.
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17. THANK YOU
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