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uwb abhi kothari

Apr 05, 2018

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Abhi Kothari
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    UWB:

    ULTRA-WIDE BAND

    Presented by:

    ABHI KOTHARI

    [email protected]

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    UWB: What is it?

    Ultra-Wideband is defined by the FCC (Federal Communications

    Commission) as a transmission whose bandwidth is either:

    -20% of its center frequency-At least 500 MHz wide

    Narrowband Bf < 1%

    Wideband 1% < Bf < 20%

    Ultra-Wideband Bf > 20%

    Ultra wide band technology working can be applicable on the places

    where the distance is shorter and needs transmission of higher

    speed.

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    So why UWB is interesting?

    7.5 Ghz of free spectrum in the U.S.

    FCC recently legalized UWB for commercial use

    Spectrum allocation overlays existing users, but its allowed powerlevel is very low to minimize interference

    Very high data rates possible

    500 Mbps can be achieved at distances of 10 feet under current

    regulations

    The peak or instantaneous power of individual UWB pulses can berelatively large, but because they are transmitted for only a very short

    time (Ton < 1nanosecond), the average power becomes

    considerably lower.

    .

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    Narrow band 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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    UWB v/s NB: modulation

    Frequency

    Modulation

    2.4 GHz

    Narrowband

    Communicatin

    0 1 0 1

    Time-domain behavior Frequency-domain behavior

    Impulse

    Modulation

    3 10 GHzfrequency

    Ultrawideband

    Communication

    time

    1 0 1

    (FCC Min=500Mhz)

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    mpulse modulation Impulse Radio (IR): the use of extremely short duration pulses (sub-

    nanosecond) instead of continuous waves to transmit information.

    The pulse directly generates a very wide instantaneous bandwidth

    signal according to is property. As frequency is inversely related to time, the short-duration UWB

    pulses spreadtheir energy across a wide range of frequencies from

    near DC to several Gigahertz (GHz)

    Spread-spectrum techniques are methods by which a signal

    generated in a particular bandwidth is deliberately spread in the

    frequency domain, resulting in a signal with a wider bandwidth

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    mpulse modulation (contd)

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    COMPARISION

    UWB is a form of extremely wide spread spectrum where RF energyis spread over gigahertz of spectrum

    Wider than any narrowband system by orders of magnitude Power seen by a narrowband system is a fraction of the total

    UWB signals can be designed to look like imperceptible random noise toconventional radios

    Narrowband (30kHz)

    Wideband CDMA (5 MHz)

    UWB (Several GHz)

    Frequency

    Part 15 Limit

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    UWB Signal Propagation

    Generally follow a free space propagation law.

    Millions of coded pulses transmitted per second.

    Emissions below conventional receiver noise floor and across an

    ultra wide bandwidth.

    Low probability of detection and interception.

    UWB systems reside below the noise level of a typical narrowband

    receiver and enables UWB signals to coexist with current radio

    services with minimal or no interference.

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    Dells UWB Usage Models

    Peripherals

    Displays

    Human Interface Devices

    Mobilephones

    Digital Home

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    Applications Digital video camcorder (DVC)

    Smartphone/PDS, Media player

    Requirements Range is in view of display (