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    Understanding Ultra Wideband Technology: Advantages, Applications and Regulatory Policy

    Master of Arts in Law and Diplomacy Thesis

    Deepali Iyengar Page 1 5/23/02

    THE FLETCHER SCHOOL OF LAW & DIPLOMACYTufts University

    Understanding Ultra Wideband Technology: Advantages,

    Applicat ions and Regulatory Policy

    Deepali Iyengar

    MALD 2002

    Prof. Lee McKnight

    MALD Thesis

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    Master of Arts in Law and Diplomacy Thesis

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    ABSTRACT

    Ultra-Wideband (UWB) is a wireless technology for transmitting large amounts of

    digital data over a wide spectrum of frequency bands with very low power for a

    short distance. Some of the advantages of UWB include high data rate

    performance for high speed mobile and multi-user applications, very fine range

    resolution, precision distance and positioning measurement capabilities, low

    probability of detection as well as low system complexity and low cost. The

    disadvantages of UWB include the possibility of interference with other systems

    and signal noise.

    The purpose of this thesis is to understand Ultra Wideband Technology and its

    applications and to see whether this technology is really breakthrough and

    whether it is a viable technology for the future.

    Different applications for Ultra Wideband technology are classified under three

    main areas: Communications, Radar and Tracking. UWB communications

    applications include: in-building communications systems, indoor broadband

    cellular phones, private radios, and wireless broadband Internet access. Radar

    applications of UWB technology include: through-wall sensing radar, security

    systems tracking movement, collision avoidance sensors for cars and boats,

    industrial robotic controls and advanced highway construction and inspection

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    and the FCC are not convinced that this overlap would not cause interference

    with other existing technologies as well as with defense and aviation frequencies.

    Hence they have been very cautious with their policies for commercializing UWB.

    Therefore, it would probably be more beneficial for the propagators of Ultra

    Wideband, to first commercialize this technology in developing countries, which

    are still establishing their telecommunication infrastructures. These countries

    would be more willing to adapt to UWB as it would benefit them greatly and the

    companies involved in UWB would have ready markets in which they could test

    their products and prove their effectiveness. Once established in these markets,

    it would be easier for them to make inroads into developed countries.

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    traffic. Today, huge amounts of R&D are being spent to develop new methods

    that more efficiently use each radio frequency band.

    One new and interesting technology is gaining prominence in the industry today.

    This new technology is considered to be a breakthrough as it is not restricted to a

    particular band of spectrum, but in fact, overlays itself over existing spectrum,

    thus making better use of available bandwidth. It is known as Ultra Wideband

    Technology. This paper will be focusing on the various aspects of Ultra

    Wideband Technology including its advantages, commercial applications and

    also the regulatory policies surrounding it.

    As this is such a cutting edge technology, there is not much information on Ultra

    Wideband that is found in either books or industry journals. For example, even

    the latest issue of the IEEE Communications magazine (April 2002), which has a

    special edition on Wideband technology, does not address Ultra Wideband in any

    significant way. Thus, the author had to rely on information from company

    sources and white papers to research and study this subject.

    What is Ultra Wideband Technology?

    Ultra-Wideband (UWB) is an alternative wireless communications technology that

    offers the promise of high bandwidth wireless communications without the

    constraints of spectrum allocation. Fundamentally different from conventional

    radio frequency communications, UWB relies on a series of narrow, precisely

    timed pulses to transmit digital data. Transmitters and receivers that use UWB

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    can be much simpler to build than their conventional counterparts, resulting in

    lower cost and higher power efficiency. Moreover, the inherent properties of

    UWB emissions allow them to potentially coexist with conventional wireless

    systems on a non-interfering basis1.

    Ultra Wideband radio is a revolutionary wireless technology for transmitting

    digital data over a wide spectrum of frequency bands with very low power. It can

    transmit data at very high rates (for wireless local area network applications) and

    very low rates (for telemetry applications). Within the power limit allowed under

    the current FCC regulations, Ultra Wideband can not only carry huge amounts of

    data over a short distance at very low power, but also has the ability to carry

    signals through doors and other obstacles that tend to reflect signals at more

    limited bandwidths and a higher power. At higher power levels, UWB signals can

    travel to significantly greater ranges. Instead of traditional sine waves, Ultra

    Wideband Radio broadcasts digital pulses that are timed very precisely on a

    signal across a very wide spectrum at the same time. Transmitter and receiver

    must be coordinated to send and receive pulses with an accuracy of trillionths of

    a second2.

    The term "ultra wideband" is a relatively new term to describe a technology,

    which had been known since the early 1960s as carrier-free, baseband, or

    "impulse" technology. The basic concept is to develop, transmit and receive an

    1 Tomorrows Technology Teachers, Ultra wideband Technology What is it? August 1999. Available at

    http://ed.tsud.edu/tcubed/whats_this/whats_this_intro.htm (visited on October 5, 2001)

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    extremely short duration burst of radio frequency (RF) energy typically a few

    tens of picoseconds (trillionths of a second) to a few nanoseconds (billionths of a

    second) in duration. These bursts represent from one to only a few cycles of an

    RF carrier wave. The resultant waveforms are extremely broadband, so much so

    that it is often difficult to determine an actual RF center frequency thus, the

    term "carrier-free". Early methods of signal generation utilized "baseband" (i.e.,

    non-RF), fast rise-time pulse excitation of a wideband microwave antenna to

    generate and radiate the antennas effective "impulse" response. (More

    precisely, it is the antennas "step" response that is actually produced.) More

    modern UWB systems, no longer utilize direct impulse excitation of an antenna

    because of the inability of such an approach to adequately control emission

    bandwidths and apparent center frequencies3.

    Please refer to Exhibit 1 at the end of the paper, for a diagram that shows the

    Emission Bandwidth of a UWB transmitter.

    History of Ultra Wideband Technology4

    The only radio technologies available in the earliest days of wireless at the end of

    the 19th century and at the beginning of the 20th century were pulse radios. In

    1893, Heinrich Hertz used a pulsed spark discharge to generate electromagnetic

    waves for his experiments, and for 20 years thereafter, spark gaps and arc

    2

    Ibid3 What is Ultra Wideband Technology May 2000. Available at

    www.aetherwire.com/CDROM/Welcome.html (Visited on October 3, 2001)

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    discharges between carbon electrodes were the principal mechanisms for

    producing these signals. Eventually, rotating generators and later vacuum tube

    and solid-state oscillators were used to produce sinusoidal radio waves.

    Receivers could then discriminate among transmitters operating at different

    frequencies.5

    In 1942, Louis de Rosa filed for two patents. On November 23 he sought one for

    radio detection systems in which the transmission of impulses may occur either

    steadily or at random. He applied for the second patent, random impulse

    system, a few weeks after the first, on December 18, 1942, and received it more

    than eleven years later, in 1954 it was among numerous patents that were

    frozen until long after WW II because the U.S. government believed they covered

    critical wartime secrets. Conrad H. Hoeppner filed for another core patent in

    November 1945, and received it sixteen years later, in September 1961. It

    outlines a pulse communication system meant to reduce interference and

    jamming, and to enhance specificity, reliability, and secrecy.6

    Modern contributions to the field of UWB stepped up in the late 1960s with the

    published work of Gerald Ross at the Sperry Corporation and Henning Harmuth

    at Catholic University, who studied the main components of a UWB transmission

    4

    Fantasma Networks, Ultra Wideband: An Emerging Technology for Wireless Communications G

    Roberto Aiello, Minnie Ho, Jim Lovette. Available at www.fantasma.net (visited on February 26, 2002)5 Fantasma Networks, Ultra Wideband: An Emerging Technology for Wireless Communications6 Fantasma Networks, Ultra Wideband: An Emerging Technology for Wireless Communications

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    system and established the basic design for UWB transceivers. The main focus

    was on pulse generation and detection techniques7.

    Since the 1960s and 1970s, UWB technologies have been developed for

    commercial non-communications applications. By the late 1990s new

    implementations of UWB components as well as a better understanding of

    system characteristics have taken UWB technologies to a stage of maturity that

    allows the building and commercialization of high performance, low cost wireless

    communication systems. Most UWB developments are still in the laboratory

    because the FCC has not yet authorized their use. In the same period, an

    explosive growth of consumer demand for access to networked and media-based

    broadband information has outstripped available wireless delivery capacity8.

    In 1996, members of the wireless industry began to discuss several new wireless

    LAN standards, including BlueTooth, HomeRF, and IEEE 802.15. Each LAN

    concept was based upon different usage models and was backed by different

    telecommunications providers. The lack of an alternative, possibly international,

    frequency band forced all the standards to be based on the 2.4 GHz band, even

    though the FCC initiated the 5 GHz band in the same year9.

    Each of the standards was a small evolution of previous LAN standards,

    especially with respect to the quality of service provided for voice and video.

    7 Fantasma Networks, Ultra Wideband: An Emerging Technology for Wireless Communications8 Fantasma Networks, Ultra Wideband: An Emerging Technology for Wireless Communications

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    None approached the ability to deliver the combinations of high definition video

    and other media that were demanded by the consumer market. This shortcoming

    invigorated a search for better technologies, which called attention to the unique

    merits of UWB10.

    9 Fantasma Networks, Ultra Wideband: An Emerging Technology for Wireless Communications10 Fantasma Networks, Ultra Wideband: An Emerging Technology for Wireless Communications

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    2. Features of Ultra Wideband Technology

    Ultra Wideband and Wideband Technology

    Ultra Wideband Technology is part of a larger gamut of technology known as

    Wideband or Broadband technology. To understand Ultra Wideband better, let us

    first try to understand wideband or broadband.

    Wideband and Broadband are two synonymous terms used for the same

    technology. In general, wideband or broadband refers to telecommunication in

    which a wide band of frequencies is available to transmit information. It is a

    transmission medium or channel that has a wider bandwidth than one voice

    channel (with a carrier wave of a certain modulated frequency). Because a wide

    band of frequencies is available, information can be multiplexed and sent on

    many different frequencies or channels within the band concurrently, allowing

    more information to be transmitted in a given amount of time. It is generally

    agreed that Digital Subscriber Line (DSL) and cable TV are broadband services

    in the downstream direction11.

    Various definers of wideband or broadband have assigned a minimum data rate

    to the term. Here are a few:

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    Newton's Telecom Dictionary: "...greater than a voice grade line of 3

    KHz.some say [it should be at least] 20 KHz."

    J upiter Communications: at least 256 Kbps.

    IBM Dictionary of Computing: A broadband channel is "6 MHz wide."12

    Thus, Ultra Wideband, which is a part of wideband, is a wireless technology for

    transmitting large amounts of digital data over a wide spectrum of frequency

    bands with very low power for a short distance. Ultra wideband radio not only can

    carry a huge amount of data over a distance up to 230 feet at very low power

    (less than 0.5 milliwatts), but also has the ability to carry signals through doors

    and other obstacles that tend to reflect signals at more limited bandwidths and a

    higher power. Ultra wideband can be compared with another short-distance

    wireless technology, Bluetooth, which is a standard for connecting handheld

    wireless devices with other similar devices and with desktop computers. 13

    Ultra wideband broadcasts digital pulses that are timed very precisely on a

    carrier signal across a very wide spectrum (number of frequency channels) at the

    same time. Transmitter and receiver must be coordinated to send and receive

    pulses with an accuracy of trillionths of a second. On any given frequency band

    that may already be in use, the ultra wideband signal has less power than the

    11

    Ross D. Murch, Khaled Ben Lataief, Wideband Wireless Access Technologies to Broadband Internet,

    IEEE Communications Magazine, April 200212

    Ibid13 Search Networking, Ultra Wideband Definition Available at

    http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci213243,00.html (visited on February 27,

    2002)

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    normal and anticipated background noise so theoretically no interference is

    possible. Time Domain, a company applying to use the technology, uses a

    microchip manufactured by IBM to transmit 1.25 million bits per second, but

    believes that there is the potential for a data rate in the billions of bits per

    second14.

    The term Wideband is commonly contrasted with the term Narrowband.

    Generally, narrowband describes telecommunication that carries voice

    information in a narrow band of frequencies. More specifically, the term has been

    used to describe a specific frequency range set aside by the U.S. FCC for mobile

    or radio services, including paging systems, from 50 cps to 64 Kbps.15

    Advantages of Ultra Wideband Technology

    Since UWB waveforms are of such short time duration, they have some rather

    unique properties. In communications, for example, UWB pulses can be used to

    provide extremely high data rate performance in multi-user network applications.

    For radar applications, these same pulses can provide very fine range resolution

    and precision distance and/or positioning measurement capabilities. In fact,

    14

    Ibid15

    Search Networking, Narrowband Definition Available at

    http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci213243,00.html (visited on February 27,

    2002)

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    multifunction architectures encompassing communications, radar and positioning

    applications have been developed16.

    These short duration waveforms are relatively immune to multipath cancellation

    effects as observed in mobile and in-building environments. Multipath

    cancellation occurs when a strong reflected wave e.g., off of a wall, ceiling,

    vehicle, building, etc. arrives partially or totally out of phase with the direct path

    signal, causing a reduced amplitude response in the receiver. With very short

    pulses, the direct path has come and gone before the reflected path arrives and

    no cancellation occurs. As a consequence, UWB systems are particularly well

    suited for high-speed, mobile wireless applications. In addition, because of the

    extremely short duration waveforms, packet burst and time division multiple

    access (TDMA) protocols for multi-user communications are readily

    implemented17.

    As bandwidth is inversely related to pulse duration, the spectral extent of these

    waveforms can be made quite large. With proper engineering design, the

    resultant energy densities (i.e., transmitted Watts of power per unit Hertz of

    bandwidth) can be quite low. This low energy density translates into a low

    probability of detection (LPD) RF signature. An LPD signature is of particular

    interest for military applications (e.g., for covert communications and radar);

    however, an LPD signature also produces minimal interference to proximity

    16 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ), September

    27, 2001. Available at http://www.multispectral.com/UWBFAQ.html (visited on October 17 2001)17 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)

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    systems and minimal RF health hazards, significant for both military and

    commercial applications18.

    Among the most important advantages of UWB technology, however, are those

    of low system complexity and low cost. UWB systems can be made nearly "all-

    digital", with minimal RF or microwave electronics. Because of the inherent RF

    simplicity of UWB designs, these systems are highly frequency adaptive,

    enabling them to be positioned anywhere within the RF spectrum. This feature

    avoids interference to existing services, while fully utilizing the available

    spectrum19.

    Disadvantages of Ultra Wideband Technology

    As with any technology, there are always applications that may be better served

    by other approaches. For example, for extremely high data rate (10s of

    Gigabits/second and higher), point-to-point or point-to-multipoint applications, it is

    difficult today for UWB systems to compete with high capacity optical fiber or

    optical wireless communications systems. Of course, the high cost associated

    with optical fiber installation and the inability of an optical wireless signal to

    penetrate a wall dramatically limits the applicability of optically based systems for

    in-home or in-building applications. In addition, optical wireless systems have

    18 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)19 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)

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    extremely precise pointing requirements, obviating their use in mobile

    environments20.

    UWB is an RF wireless technology, and as such is still subject to the same laws

    of physics as every other RF technology. Thus, there are obvious tradeoffs to be

    made in signal-to-noise ratio versus bandwidth, range versus peak and average

    power levels, etc21.

    Overlap between Ultra Wideband and Other Systems

    UWB is a Radio Frequency technology and has the potential to interfere with

    existing systems if not properly designed. Furthermore, there are several ways in

    which UWB emissions can be generated. Some of these techniques are more

    prone to generate harmful interference effects than are others. For example,

    UWB systems, which utilize direct impulse excitation of an antenna, produce

    energy, which is typically spread over a spectral extent significantly greater than

    the design bandwidth of the antenna. Unfortunately, it is very difficult to tightly

    control the bandwidth and center frequency of such emissions with an antenna

    alone, and the end result is that these emissions typically span restricted bands

    set aside by the Federal Communications Commission22.

    Other important aspects of UWB design, which directly impact interference

    potential, include pulse duty cycle and modulation strategy. Of course, the higher

    20 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)21 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)22 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)

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    the pulse duty cycle, the greater the average amount of energy transmitted. In

    some proposed UWB schemes, multiple pulses are transmitted per single bit of

    information. This has the effect of further increasing the total amount of energy

    transmitted, or forcing the designer to accept a much lower data rate for a given

    average energy. In addition, a high pulse repetition frequency (PRF) has the

    effect of further concentrating this energy into a set of spectral lines. When a

    spectral line falls into the band of a sensitive receiver (e.g., GPS), considerable

    interference can result23.

    But, more modern techniques create a UWB waveform through pulse shaping

    prior to transmission from an antenna. These techniques have the considerable

    advantage of being controllable, both in frequency and bandwidth; and can be

    made to operate outside of restricted bands such as those reserved for GPS and

    safety of life systems24.

    23 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)24 Multispectral Solutions Inc, Ultra Wideband (UWB) Frequently Asked Questions (FAQ)

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    3. Major Players in the UWB Market

    Time Domain Corporation

    Time Domain Corporation is considered by most people to be the founder and

    chief propagator of Ultra Wideband Technology. Time Domain has developed

    PulsON TM chipsets and chip designs based upon the Time Modulated Ultra

    Wideband (TM-UWB) architecture. PulsON TM technology transmits pulse trains

    of individual ultra-wideband pulses at very precise time intervals. The result: a

    low power, noise-like signal that can transmit data, voice and video

    communications; can be used as a personal radar; or can be used as a

    positioning and tracking device. The TM-UWB architecture was conceived as a

    means to enable high-bandwidth transmissions in the increasingly crowded

    spectrum. The TM-UWB technology is radically different from the traditional sine

    wave technology used in current wireless technology such as CDMA and

    TDMA25.

    The TM-UWB architecture is characterized by:

    Ultra-short duration pulses which yield ultra-wide bandwidth signals

    Extremely low power spectral densities

    25

    Time Domain Corporation, PulsON Technology Time Modulated Ultra Wideband for Wireless

    Applications, June 2000, Available at

    http://www.ero.dk/EROWEB/SRD/UWB/Time%20Domain/Tech%20Overview%20400-0001%20A.pdf

    (visited on October 21, 2001)

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    Center frequencies typically between 650 MHz and 5 GHz, with potential to

    go higher as technology advances

    Multi-mile ranges with sub-milliWatt average power levels (even with low gain

    antennas)

    Excellent immunity to interference from other radio systems26.

    Time Domain uses Application Specific Integrated Circuits (ASICs) to implement

    its PulsON technology into the market via products made by existing legacy

    companies, and to enable the incorporation of this technology into entirely new

    markets. Time Domain has developed two chips specific to TM-UWB radios. The

    first chip, the Timer, is capable of handling the 10-picosecond timing required by

    the radios. The second chip is a Correlator. It consists of a variable gain amplifier

    and three independent correlating circuits. Both of the RF chips have been

    developed using the Silicon Germanium process. These chips constitute the bulk

    of the RF portion of the radio. The third chip, a Digital Baseband Signal

    Processor and Controller, is currently under design27.

    Products based upon the PulsON chipset are expected to enjoy the following

    benefits:

    Exceptional multipath immunity

    Relatively simple and likely less costly to build than spread spectrum radios

    26 Time Domain Corporation, The Pulse of the Future, Available at

    http://www.timedomain.com/Files/HTML/pressreleases/reportandorderfcc.html (visited on October 21,

    2001)

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    Home wireless networks

    Numerous public safety applications involving motion detection through

    walls or rubble.

    In-building personnel and asset tracking

    High-speed local area networks and wide area networks

    Invisible security domes and fences

    Collision avoidance sensors

    Ultra high precision positioning/tracking systems30

    Multispectral Solutions Inc.

    Multispectral Solutions (MSSI) has had a long history of developing and fielding

    UWB hardware and systems for a large number of Government and military

    customers and applications. With its patented UWB receiver technology, MSSI

    has demonstrated the ability to detect single pulses of UWB energy with

    extremely high sensitivity and in the presence of high interference. A single-pulse

    detection capability is critical for high-speed mobile wireless applications. Single-

    pulse detection also allows for a significant reduction in transmitted power, with

    resultant reduction in interference potential to other systems. The unique

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    properties of MSSI's detector also include the ability to respond to the leading

    edge of a UWB pulse, enabling applications for precision positioning and

    geolocation for buildings and environments with multi-paths31.

    MSSI's patented UWB transmitter design provides for architectures adapted for

    different frequencies as well as several bandwidths. These unique architectures

    enable the development of UWB systems which can coexist with existing spectral

    users without mutual interference, while minimizing the peak and average power

    levels required for reliable communications. Also, MSSI's technology has been

    proven competent through extensive field tests and evaluations in harsh

    electromagnetic environments32.

    Since its inception, MSSI has received a total of 43 contract awards (as of 21

    November 2000) to develop UWB systems for the U.S. Government and military.

    These systems have included:

    Tactical handheld & network-capable LPI/D radios LPI/D standing for low

    probability of intercept and detection. These radios are designed for mobile

    ad hoc wireless network communications with data rates to 1.544 Mb/s;

    Non line-of-sight, surface wave communications systems, which utilize the

    unique properties of the earth to allow ultra wideband communications over

    difficult or blocked terrain;

    30

    Mobileinfo.com, US West takes stake in Time Domain to explore Ultra Wideband31 Multispectral Solutions Inc., History and Overview Available at www.multispectral.com/history.html

    (visited on 12/7/2001)32 Ibid

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    Datalinks for unmanned aerial vehicles (UAVs) and ground robotic vehicles

    these are used for the relay of video and data from these platforms, as well as

    for command & control of the vehicles. Data rates to 25 Mb/s have been

    demonstrated, with higher data rates envisioned for future applications;

    UWB wireless intercom systems for secure communications on-board aircraft.

    These wireless systems use digital voice transmissions having significantly

    improved audio quality over existing, tethered systems.

    UWB tags for Intelligent Transportation System (ITS) applications including

    vehicle-to-vehicle and vehicle-to-roadside communications, as well as unique

    applications such as the detection of problem (i.e., suspended license)

    drivers;

    High accuracy UWB precision geolocation systems for 3-D location of

    materiel or personnel in both indoor and urban environments without the use

    of the Global Positioning System (GPS);

    Collision and obstacle avoidance radars for helicopters, micro air vehicles,

    large mining equipment, etc. One specific example was the development of a

    UWB obstacle avoidance radar which could detect a small diameter power

    line a serious threat to helicopter air safety;

    High precision altimeters for height above ground level determination in

    helicopters and other air platforms;

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    LPI proximity fuses for "smart munitions" these are extremely precise radars

    which are very difficult to jam; and,

    Intrusion detection radars for wide area surveillance, as well as "through-the-

    wall" sensors for detection of personnel behind walls or other obstacles33.

    Fantasma Networks Inc.

    Fantasma Networks was formed to provide solutions to eliminate the obstacles

    that prevent the sharing of content, connections, and peripherals in the home.

    While common data types including MPEG and HTML are seemingly driving the

    convergence of the PC and consumer electronics worlds, networking solutions

    haven't kept pace. Today's solutions were developed for corporate applications

    and do not address the unique performance or ease of use requirements

    necessary for widespread consumer adoption34.

    In 1996, under the direction of G. Roberto Aiello, a project team began a best of

    breed technology approach to solving the entertainment-networking problem.

    Fantasma Networks became an independent organization in January 2000, with

    the charter to combine ultra-wideband (UWB) radio transmission technology,

    33

    Multispectral Solutions Inc, Perspectives on Ultra Wideband Technology, Available at

    http://www.darpa.mil/ipto/research/netex/presentations/Fontana.pdf (visited on 12/7/2001)34 Fantasma Networks, Overview, News and Press Releases, Available at

    www.fantasma.net/content/news_content.shtml (visited on 02/02/2002)

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    which is particularly well suited to short-range broadband networking, and a

    network architecture designed for consumer applications35.

    In May 2001, Fantasma Networks was acquired by Pulse-Link Inc., another

    company innovating UWB technologies. All continued product development is

    occurring at Pulse-Link's offices in San Diego, California. In recognition of and

    respect for the outstanding work, commitment and accomplishments of the

    Fantasma team, Pulse-Link has chosen to continue identifying the UWB

    technology pioneered at Fantasma Networks under the Fantasma name36.

    The Fantasma chipset provides reliable wireless video networking. Its silicon-

    based solutions combine a flexible networking protocol with ultra-wideband

    (UWB) radio technology to provide a simple yet powerful solution for distributing

    high quality video throughout the home. Designed from inception to meet

    consumers' high quality of service expectations, Fantasmas network architecture

    provides ease of installation and unmatched multi-stream reliability37

    In 1996, the original Fantasma team set out to develop a system for distributing

    digital content, including high quality video, throughout homes, schools, and

    other indoor environments. This initial idea coupled with extensive user

    requirements research led to the current Fantasma technology platform

    35 Fantasma Networks, Overview, News and Press Releases36 Fantasma Networks, Overview, News and Press Releases37 Fantasma Networks, Overview, News and Press Releases

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    consisting of an ultra-wideband (UWB) physical layer and a networking protocol

    ideal for entertainment based digital content38.

    Fantasma's UWB physical layer is the wireless link between networked devices.

    UWB was chosen for four key reasons: reliability, high throughput, ease of use

    and affordability. Fantasma's wireless network was able to achieve the most

    reliable wireless solution because its UWB implementation is robust to the effects

    of interference, multi-path fading and poor propagation frequently encountered

    with existing indoor solutions. Using pulse-amplitude modulation, Fantasma's 1st

    generation product will transmit data at 60Mbps, providing more than enough

    throughput to simultaneously transmit multiple video streams. Because this

    solution has been continuously developed with the end user in mind, ease of use

    and affordability have been consistent design constraints. For example, UWB

    systems have relatively fewer analog radio frequency components allowing more

    user benefits within the cost constraints of consumer price points39.

    The other essential part of Fantasma's solution is the networking protocol.

    Network protocols designed for data-centric traffic generally do not meet the

    requirements of networks transmitting digital audio and video content. These

    digital video networks require time synchronization for audio and video stream

    support, high-traffic network stability, and prioritization to ensure quality of

    service for the audio/video streams. Fantasmas network protocol specifically

    addresses issues such as uncontrolled deployment, a mixture of both time

    38 Pulse-Link Inc., Ultra Wideband Technology, Available at www.pulselink.net/technology/default.htm

    (visited on 02/02/2002)39 Pulse-Link Inc., Ultra Wideband Technology

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    bounded (A/V) and bursty (data) traffic, support of a high continuous load, and

    the ability to negotiate traffic during transmission within a single channel, with

    minimized interruption or interference40.

    Intel

    Intel Architecture Labs (IAL) is currently researching UWB technology in order to

    better understand its benefits, limitations, and technical challenges when used for

    high-rate communications.

    One of the important aspects in this case is the fact that the Federal

    Communications Commission (FCC) is currently working on setting emissions

    limits that would allow UWB communication systems to be deployed on an

    unlicensed basis. This rule change would allow UWB-enabled devices to overlay

    existing narrowband systems, which is currently not allowed, and result in a

    much more efficient use of the available spectrum. Devices could, in essence, fill

    in the unused portions of the frequency spectrum in any particular location.

    These recent developments by the FCC have given Intel a unique opportunity to

    develop equipment that could potentially take advantage of the vast amount of

    usable spectrum that exists in the wireless space, and that could provide an

    40 Fantasma Networks, Overview, News and Press Releases

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    engine to drive the future high-rate applications that are being conceived

    throughout this industry.

    Intel has identified several areas that show the promise of UWB for use in high-

    rate, short to medium-range communications. These include potential low-cost

    implementations, low-power consumption due to limits on transmit power spectral

    density, high output afforded by the wide occupied bandwidth, accurate position

    location that can be combined with communications capabilities, and favorable

    multi-path fading robustness due to the nature of the short impulse. However,

    there are still challenges in making this technology live up to its full potential. The

    regulatory process is still in motion. Intel is involved in helping the Federal

    Communications Commission (FCC) identify emission limits favorable to Ultra-

    Wideband (UWB) systems that allow them to be competitive within the

    marketplace, while at the same time not allowing them to cause an unacceptable

    level of interference for other wireless services that happen to be sharing the

    same frequency band. The FCC regulations are just a first step in this process,

    and it is anticipated that standardization will be needed in the future to help make

    this technology ubiquitous in the consumer market41.

    In addition, Intel has identified three main areas that are important for helping

    UWB make the best use of this newly available spectrum. First, as discussed

    previously, a reliable model is critical for helping to predict performance as well

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    as for optimizing the physical design. In this regard, Intel is actively engaging the

    industry to help determine a reliable model that systems engineers can use to

    help study the performance of UWB systems. Second, Intel is investigating

    several receiver designs that will help to improve the robustness and long-term

    viability of this technology. This includes the ability to capture the significant

    amount of energy that will be present in the multiple reflections caused by the

    channel, and mechanisms for suppressing the narrowband interference that will

    typically be seen in this type of overlay environment. Finally, Intel is investigating

    the feasibility for high-level silicon integration in order to yield a very low-cost and

    low-power solution42.

    41

    Intel Technology Journal, Ultra Wideband Technology for Short or Medium Range Wireless

    Communications, Available at http://developer.intel.com/technology/itj/q22001/articles/art_4.htm (visited

    on 11/09/2001)42 Intel Technology Journal, Ultra Wideband Technology for Short or Medium Range Wireless

    Communications

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    4. Potential Markets and Applications

    Potential Markets for Ultra Wideband Technology

    The potential markets for UWB can be broadly classified into three areas:

    Communications, Radar and Tracking. We will now be discussing each of these

    in a little more detail.

    Communications

    UWB technology provides reliable high speed and high performance wireless

    networks transmitting megabits of information for many new wireless

    applications. UWB technology can support high data rate links at very low power

    levels. Communications products will benefit from Ultra Wideband Technologys

    excellent performance in multipath reflective environments (such as inside

    buildings and other highly cluttered areas), and high bandwidth, multi-channel

    performance. UWB communications applications include: in-building

    communications systems, indoor broadband cellular phones, private radios, and

    wireless broadband Internet access43.

    Some of the uses of Ultra Wideband Technology in communications are:

    43 Time Domain Corporation, Applications of Ultra Wideband Technology, Available at

    www.ero.dk/EROWEB/SRD/UWB/Time%20Domain/Tech%20Overview%20400-0001%20A.pdf(visited

    on 10/13/2001)

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    A Smart Home environment providing mobile connectivity for all fixed and

    mobile "smart home" appliances such as computers, security systems,

    PDA's and gaming, and televisions and stereos. Home systems can be

    provided with high bandwidth, low power links.

    Wireless Networks supplying short- range indoor data and video

    communications without multipath interference.

    Indoor Wireless Communications transmitting voice, data, and video --

    not susceptible to multipath and not impairing the performance of existing

    devices.

    Rural Access Systems supplying wireless self-configuring networks that

    bring voice and data direct to users in remote areas44.

    Radar

    Ultra Wideband technology enables high performance, high-resolution radar

    systems. Radars using UWB technology can be range gated, have excellent

    clutter rejection, possess the highest resolution at the lowest possible frequency,

    attain excellent penetration results, and can function as both imagers and motion

    sensors. Unlike today's infrared and Doppler radars, UWB security sensors

    cannot be evaded - even a stealthy target would be detected! Radar applications

    44 Time Domain Corporation, Applications of Ultra Wideband Technology

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    Ultra Wideband Technology's use of an ultra precise positioning system can

    provide seamless indoor and outdoor tracking for many applications. Devices

    using UWB technology fuse tracking and communications into a single device

    and can measure both distance and position with an accurate positioning range

    of less than one inch. The technology's advanced time resolution and the pulse

    nature of the transmitted signal result in exceptional multipath resistance.

    Examples of UWB precision tracking applications include: personnel and asset

    tracking for increased safety and security, location-based content delivery

    systems, and mobility-based commerce capabilities

    47

    .

    Ultra Wideband Technology uses in real time tracking are:

    Locator Beacons aiding Emergency 911 services and tracking mobile

    inventory with highly accurate 3-D asset tracking.

    Indoor Tracking and Communication with children, elderly, co-workers

    and fire and rescue teams.

    Precision Navigation devices improving the safety and performance of

    vehicles and agricultural and industrial equipment.

    Precision Location devices supporting public safety, military and rescue

    teams.

    47 Time Domain Corporation, Applications of Ultra Wideband Technology

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    Ranging Instruments determining precise distances between objects for

    precision surveying and measurement48.

    Appl ications of Ultra Wideband Technology

    The following are some examples of products that use Ultra Wideband

    Technology and its various applications.

    Exhibit 2: Applications of UWB Technology

    Communications Applications Radar Applications

    Ultra Wideband Handheld Transceiver HummingbirdUWB Altimeter and Collision Avoidance Sensor

    Radio for non line-of-sight communications UWB Backup Sensor

    Radio for Digital Voice and DataUWB Electronic License Plate

    Compressed Video RadioX-Band UWB Fuse Sensor

    Ultra Wideband Tag and Tag ReaderUWB Through-The- Wall Intrusion Sensor

    UWB TransceiversRadar Collision Avoidance

    UWB Wireless Intercom Communications System

    UWB TacticalAd Hoc Wireless Networks

    UWB Precision Geolocation Communication Transceiver

    Ultra Wideband Handheld Transceiver - This was designed for full duplex

    voice and data transmission at rates of up to 128 kb/s (CVSD) and 115.2 kb/s

    (RS232). The radio has an operational center frequency in L-band (1.5 GHz) with

    48 Time Domain Corporation, Applications of Ultra Wideband Technology

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    an instantaneous bandwidth of 400 MHz (27% fractional BW). Peak power output

    from the UWB transceiver was measured at 2.0 Watts, with a resultant average

    power (worst case) of 640 mW. This results in a worst-case power density of 1.6

    pW/Hz. These units have a range of approximately 1 to 2 km (with small

    antennas shown and line-of-sight), and an extended range of 10 to 20 miles with

    small gain antennas49.

    Radio for non line-of-sight communications This radio was designed for

    non line-of-sight communications utilizing surface or ground wave propagation.

    To excite such propagation modes, the frequency of operation needs to be well

    below 100 MHz. Thus, this system was designed to operate in the frequency

    band from 30 to 50 MHz (50% fractional BW) and utilized a peak power output of

    approximately 35 Watts50.

    Radio for Digital Voice and Data - this radio is capable of both digital voice and

    data transmission to 128 kb/s and had an operational range over water of

    approximately 10 miles using a standard SINCGARS (30-88 MHz) VHF military

    antenna. Operational range over land depended upon terrain, but was observed

    to be from 1 to 5 miles with intervening foliage, buildings and hills. [Multipath

    cancellation is a serious problem over water, even with UWB impulse technology,

    49 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems, Available at http://www.multispectral.com/pdf/UWBApplications.pdf (visited

    on 02/22/2002)

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    because of the typically low grazing angles (resulting in small differential delays

    between direct and reflected paths) and strong, out-of- phase reflection from the

    water surface]. Also unique to the receiver design is the addition of anti-jam

    circuitry to prevent loss of sensitivity due to strong, in-band interferers commonly

    observed in this frequency range51.

    Compressed Video Radio This is a high-speed (up to 25 Mb/s) UWB radio

    designed for transmission of compressed video and command & control

    information across an asymmetric, bi-directional link. This system was also

    designed to operate in the 1.3 to 1.7 GHz region (27% fractional BW) with a 4W

    peak power output. An earlier design, developed under funding from the U.S.

    Defense Advanced research Projects Agency (DARPA), operated with a 500

    MHz instantaneous bandwidth in the C-band region (5.4 to 5.9 GHz). The

    ultimate goal of this design is to provide for up to 60 nautical miles, line-of-sight

    transmission to/from an unmanned aerial vehicle (UAV). A small parabolic dish

    antenna was used at the ground platform52.

    Ultra Wideband Tag & Tag Reader- This system, dubbed Vehicular Electronic

    Tagging and Alert System (VETAS), was designed for the U.S. Department of

    Transportation to provide a means for keeping problem drivers (i.e., drivers who

    have repeated been convicted of traffic accidents or violations due to driving

    50

    Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems51 Ibid52 Ibid

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    while under the influence of alcohol) off the road. The concept was to tag the

    vehicle with a device, which relays a picture of the driver, together with

    information on the driver and the vehicle, to a roadside sensor in a police vehicle.

    The tag would be installed in lieu of impounding the vehicle or placing the

    convicted driver in jail. Ultra wideband technology was considered for this

    application because of its ability to transmit large amounts of data at high speed

    in a mobile, multipath-prone environment. The UWB tag operated in the L-band

    region (1.4 to 1.65 GHz) and had a peak output power of approximately 250 mW

    for a demonstrated range of over 300 meters. The image of the driver was stored

    as a compressed J PEG file, together with additional ASCII data, in EEPROM and

    periodically transmitted at a 400 kb/s burst rate to a UWB receiver with display.

    The tag operated off of two AAA batteries (3.0V) and, in an operational scenario,

    was mounted behind the front grill of the automobile53.

    UWB transceivers These were designed for the U.S. Navy to provide a

    wireless intercom capability on-board Navy aircraft. The prototype UWB

    transceivers provide multichannel, full duplex, 32 kb/s digital voice over a range

    of approximately 100 meters. An ultra wideband waveform was selected because

    of its ability to operate in severe multipath (created by multiple RF reflections

    inside and around aircraft), and because of its non-interfering, low probability of

    intercept signature54.

    53

    Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems54 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems

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    UWB Wireless Intercom Communications System (WICS) Current

    intercommunications systems (ICS) designs for aircraft utilize lengthy, and often

    unwieldy, cords to physically attach the crewmans headset to a distributed audio

    (intercom) system. Such physical attachment presents a safety hazard to

    personnel, impedes movement throughout the platform and reduces mission

    effectiveness. Replacement of these mechanical tethers with wireless RF links is

    a desirable alternative. Frequency of operation for the WICS transceivers is

    again in the L-band region (1.2 to 1.8 GHz). One of the unique features of the

    WICS design is the use of a frequency division multiplex, time division multiple

    access (FDM/TDMA) strategy for full duplex, multi-user operation. Because of

    the extremely short duration pulsewidths and resulting low energy densities,

    UWB systems are much less vulnerable to intercept and attack than conventional

    RF communications systems. As a consequence, they also minimize interference

    with other on-board electronics, such as sensitive flight control systems, GPS,

    etc. With an extremely low duty cycle, a very low power drain can be achieved,

    thereby providing communications capability for mission life exceeding 12 hours.

    The WICS program has recently received additional funding to further improve

    and miniaturize the design55.

    55 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems

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    UWB TacticalAd Hoc Wireless Networks - One of the most recent applications

    of UWB communications technology is to the development of highly mobile,

    multi-node, ad hoc wireless communications networks. Such a system is

    currently under development for the U.S. Department of Defense. The system is

    designed to provide a secure, low probability of intercept and detection. The

    UWB ad hoc wireless network has the capability to support encrypted voice/data

    (to 128 kb/s) and high-speed video (1.544 Mb/s T1) transmissions56.

    A parallel effort, currently funded by the Office of Naval Research under a Dual

    Use Science and Technology (DUS&T) effort is developing a state-of-the-art,

    mobile ad hoc network (MANET) based upon an Internet Protocol (IP) suite to

    provide a connectionless, multihop, packet switching solution for survivable

    communications in a high link failure environment. The thrust of the DUS&T effort

    is toward commercialization of UWB technology for applications to high-speed

    (20+ Mb/s) wireless applications for the home and business57.

    UWB Precision Geolocation System Transceiver - A UWB application that

    bridges the gap between communications and radar is that of precision

    geolocation. There is a system designed to provide 3-dimensional location

    information utilizing a set of untethered UWB beacons and an untethered, mobile

    UWB rover. Precision location is derived from round trip, time-of-flight

    56 Ibid57 Ibid

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    measurements using packet burst transmissions from the UWB rover and

    beacon transponders. This system utilizes 2.5 ns, 4-Watt peak, and UWB pulse,

    again operating in the 1.3 to 1.7 GHz region. Line-of-sight range for the system is

    better than 2 kilometers utilizing small, omni directional vertically polarized

    (smaller) or circularly polarized (larger) antennas. Within a building, the range

    becomes limited by wall and obstacle attenuation; however, ranges exceeding

    100 meters inside have been attained. A unique feature of the system is the

    ability to detect the pulse leading edge through the use of a charge sensitive,

    tunnel diode detector. Leading edge detection is critical to the resolution of the

    direct path from the plethora of multipath returns produced from internal

    reflections58.

    The UWB geolocation system was originally developed to permit a soldier to

    determine his or her position to within 1-foot resolution in an urban environment.

    It is currently being used to augment a video capture system for 3-D modeling,

    and for materiel location onboard a Navy ship59.

    Hummingbird UWB Altimeter and Collision Avoidance Sensor This is an

    ultra wideband system designed as a precision altimeter and obstacle/collision

    avoidance sensor. Originally developed for the U.S. Marine Corps' Hummingbird

    unmanned aerial vehicle, the sensor has proved capable of detecting small

    58 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems

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    diameter (0.25" or 6.35 mm) suspended wires to ranges beyond 250 feet. With a

    peak output power of only 0.2 Watts, the system operates in the C-band region

    from 5.4 to 5.9 GHz (8.9% fractional BW) and has an average output power at 10

    kpps of less than 4 mW. Range resolution of the radar was better than one foot

    utilizing the leading edge detection capability60.

    For the Hummingbird application, the system incorporated a linear forward-

    looking phased array, and broad beamwidth side-looking antennas, for use in

    autonomous control. Interestingly, a predecessor ofHummingbird was developed

    for the U.S. Naval Air Systems Command as a multifunction precision altimeter,

    collision avoidance sensor and low data rate communications system. A 1-Watt

    version of the radar operated as a precision (1 foot resolution) radar altimeter to

    an altitude of better than 5000 feet. Several variants of the Hummingbird radar

    have also been developed61.

    .

    UWB Backup Sensor - Operating with approximately 250 MW peak in the C-

    band region from 5.4 to 5.9 GHz, the backup sensor utilizes a dual antenna

    configuration for the detection of objects as close as 1 foot to beyond 350 feet

    from the vehicle. Ultra wideband provides a significant advantage for this

    application because of the ability to provide precision range gating to eliminate

    59

    Ibid60 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems61 Ibid

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    clutter, which, with conventional Doppler-based sensors, often results in large

    false alarm rates. This sensor was developed for the National Institute of

    Occupational Safety and Health62.

    UWB Electronic License Plate - Another variant of the Hummingbird collision

    avoidance sensor was developed as part of an electronic license plate for the

    U.S. National Academy of Sciences' Transportation Research Board The UWB

    Electronic License Plate provides a dual function capability for both automobile

    collision avoidance and RF tagging for vehicle to roadside communications.

    Collision avoidance functions are achieved with a miniature, 500 MHz bandwidth

    C-band UWB radar; and RF tagging functions are accomplished with a low

    power, 250 MHz bandwidth L-band system63.

    The UWB C-band radar utilized a 0.2W peak power (4 mW average) waveform to

    achieve a range of better than 100 feet against other vehicles, with an accuracy

    of better than 1 foot. The L-band tag operated with a 0.3W peak power (500 mW

    average) packet burst transmission to achieve a data throughput of 128 kb/s over

    a range exceeding 800 feet. An ultra wideband solution was chosen for the

    Electronic License Plate because of its precision ranging capability (radar mode)

    and high multipath immunity (tag mode)64.

    62

    Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems63 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems64 Ibid

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    X-band UWB Fuse Sensor- This prototype sensor was developed for the U.S.

    Army Missile Command as a low probability of intercept and detection (LPI/D),

    anti-jam, radar proximity sensor for medium caliber, small caliber and

    submunition applications. The system exhibited an operational bandwidth of 2.5

    GHz with a 10 GHz center frequency. Specifically designed for very short-range

    applications (less than 6 feet), the UWB sensor has a 6-inch range resolution65.

    UWB Through-the-wall Intrusion Sensor This is a UWB intrusion sensor

    radar, which was designed for through-the- wall penetration. With an L-band

    operational frequency and 33% fractional bandwidth, this system utilizes a 1-Watt

    peak UWB waveform to detect personnel through several intervening walls.

    Broad area surveillance coverage was provided for both in-building and outdoor

    field environments. An extended range system was also developed to detect and

    track human targets at distances exceeding 1000 feet66.

    Radar Collision Avoidance - To suit radar, collision avoidance, and potentially

    synthetic vision, requirements in flight, the same types of impulses can be used

    to accurately measure scattered components in an environment better than

    conventional radar. UWB technology has been used for decades for ground-

    65

    Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems66 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems

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    penetrating radar, and one company is even able to locate striations of gold 20

    feet into rock. Dolphins naturally emit echolocation impulses similar to UWB

    waveforms to navigate in unclear waters, and have even located a meal buried a

    several feet under a sandy sea bottom. UWB radar also has the capability to

    range gate impulse returns, enabling them to ignore returns from close objects

    (like a wall, boulder, etc) and effectively see through these objects to image the

    environment on the other side67.

    UWB collision avoidance systems have already been employed in support of

    DARPAs Micro Air Vehicle (MAV) program, at least one company demonstrating

    a capability for an autonomous flying vehicle to detect and avoid objects as small

    as a 0.25 wire in the flight path. This technology could be enhanced to provide

    an autonomous flight vehicle with this capability, as well as a real-time synthetic

    view of the environment in any direction, and avoidance of other vehicles in flight.

    With additional special processing, such a system could be used in conjunction

    with the intercraft positioning processing to synchronize formation or cluster flight

    arrangements68.

    67 Robert Fontana, Multispectral Solutions Recent Applications of Ultra Wideband Radar and

    Communications Systems68 Ibid

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    5. Ultra Wideband Technology and Policy

    DARPAs Assessment of Ultra Wideband Technology

    The Defense Advanced Research Projects Agency (DARPA) and the Office of

    the Secretary of Defense set up a committee to review UWB technologies and

    applications. They convened the Ultra Wideband Radar Review Panel to

    examine state of the art and potential performance benefits and limitations of

    UWB, with particular focus on radar applications. The panel was also charged

    with identifying and prioritizing UWB research to be pursued and exploited. The

    panel worked mainly on radar applications of Ultra Wideband Technology.

    The panel found that essentially all the interest and claims for the versatility and

    usefulness of UWB radars was in the area of impulse radar implementation,

    which generates its radiated energy through applying a very short pulse to the

    antenna. The interest in these types of radars has centered on claims involving

    counter stealth, Low Probability of Intercept (LPI) and detection of relocatable

    targets in camouflage and foliage. There has also been some controversy about

    whether standard analytical tools were either inappropriate or inadequate to deal

    with impulse radar issues69

    .

    69

    Charles Fowler, John Entzminger, James Corum, DARPA- Assessment of Ultra Wideband Technology

    A Report, Available at

    http://umunhum.stanford.edu/~morf/ss/ss/UWB_CDROM_1/PAPERS/REPORT.PDF ( visited on

    10/3/2001)

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    The panel found that claims on the uniqueness of the properties and

    performance capabilities of impulse radars were overrated and in some respects,

    false. The panel did not find much theoretical or experimental evidence at

    frequencies or operating ranges of any interest to the military. But the panel also

    found that there were a lot of applications where the combination of high

    resolution and low frequency is desirable, most notably, terrain profiling and earth

    penetration as well as foliage penetration and low surveillance. The panel

    indicated that these applications should be pursued in greater detail. The panel

    suggested that impulse radar probably represents the most cost effective solution

    for terrain profiling and ground probing activities70.

    The panel concluded that in terms of counter stealth, the impulse radar is not

    inherently anti-stealth and it does not have any unique advantages in this

    respect. Also, the panel observed that impulse radar has no special LPI

    characteristics and is easily detectable by an appropriately designed intercept

    receiver. The panel also concluded that all the applications presented could be

    implemented by alternative non-impulse techniques and there was no application

    on which only impulse radar could work. It also concluded that available analysis

    tools were completely adequate and appropriate for dealing rigorously with

    impulse radar performance71.

    But the panel also made the following recommendations; -

    70 Ibid71 Ibid

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    It recommended that the Department of Defense analyses of point designs for

    four UWB radar applications that seem to have important military implications

    - A short range system for detecting moving target behind walls or

    foliage

    - A short range airborne imaging radar for detecting military targets

    under canopy or in wooded terrain

    - A medium range air defense radar for detection identification of

    airborne targets including helicopters in the tree line

    - A medium range radar for detection of sea skimming missiles in fleet

    defense applications72

    The panel also recommended that the Department of Defense fund two other

    studies relevant to UWB to help the point analyses

    - A review and analysis of the clutter behavior of UWB radar systems

    - An analysis that characterizes the range and angle pattern of UWB

    linear and planer antenna rays73

    Thus, in conclusion, though the panel did not see any significant scientific

    breakthrough for military applications with UWB, it did feel that the technology

    72

    Charles Fowler, John Entzminger, James Corum, DARPA- Assessment of Ultra Wideband Technology

    A Report73 Charles Fowler, John Entzminger, James Corum, DARPA- Assessment of Ultra Wideband

    Technology A Report

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    was interesting and should be pursued, as it could be efficient and cost effective

    in the long run74.

    FAAs Issues with Ultra Wideband Technology

    The Federal Aviation Administration (FAA) has been involved in an issue

    regarding ultra-wideband technology. The UWB systems of interest at the

    present time are generally those systems that are low-powered and use very

    narrow pulses or impulses that generate a very wide bandwidth, greater than

    25% of the center frequency. The Federal Communications Commission (FCC) is

    modifying their Part 15 rules for unlicensed, low-powered devices, which would

    allow UWB devices to be operated across radio spectrum that is used for

    international civil aviation safety-related systems75.

    In its memorandum to its members, the FAA states that the proponents of UWB

    technology believe that this technology could have enormous benefits for public

    safety, consumers and businesses. Furthermore, UWB technology could create

    new business opportunities for manufacturers, distributors and vendors that will

    enhance market competition and enhance the economy. It is believed that UWB

    technology may enable increased use of scarce spectrum resources when

    sharing among conventional narrowband technology is not feasible. It is claimed

    74

    Ibid75 RTCA Special Committee, Ultra Wideband Technology Radio Frequency Interference Effects to GPS

    and Interference Scenario Development Available at http://ostpxweb.dot.gov/policy/gps/interim1.pdf

    (visited on 02/19/2002)

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    that UWB communication devices will be able to transmit very high data rates

    over short distances without being affected by multi-path interference. The UWB

    radar imaging devices may have application in the automotive industry, for

    example for collision avoidance and air bag deployment. Public safety personnel

    could use the devices to see through walls in hostage situations or to locate

    people trapped by fire. Field disturbance devices can be used for security.

    Ground-penetrating radar can be used to detect faults in a roadbed. The

    application will dictate where a UWB device operates in the spectrum76.

    The FAA also states that the impact of UWB systems on aeronautical systems is

    not well understood at this time. The NTIA has completed two studies - one is on

    spectral characteristics of UWB signals, and the other is on the compatibility

    between UWB devices and selected federal systems. The results of the latter

    report reveal that depending on signal structure, separation distance, and height

    of the UWB device, UWB devices can interfere with various aeronautical

    systems. For the scenarios evaluated, the non-GNSS aeronautical systems that

    could be affected are distance measuring equipment (DME), air traffic control

    radar beacon system, air route surveillance radars, airport surveillance radar,

    microwave landing system, terminal Doppler weather radar, and search and

    rescue satellite land user terminals. NTIA released its report on GPS, however it

    did not include results for a civil aviation GPS receiver for en-route and non-

    precision approaches. That GPS receiver will be included in an addendum to the

    76 Aviation Week, International Civil Aviation Authority Ultra Wideband Technology Available at

    http://www.aviationnow.com/content/publication/b_ca/bca.htm (visited on 02/19/2002)

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    report later. The preliminary results from the NTIA GPS report shows that UWB

    overlay with GPS will be challenging and require UWB signal structure

    dependent regulations and restrictions to ensure compatibility. Preliminary

    analyses and tests by the DOT have shown that interference to GPS receivers

    can occur from even a single UWB device. The DOT has also published a report

    on GPS receivers including an aeronautical receiver for precision approaches

    and landings. Preliminary results of these tests are similar to the results obtained

    by NTIA77.

    The private sector has also performed GPS/UWB tests. The raw data from the

    tests are still being evaluated. The FCC states that it will also consider these

    results. The draft question calls for a study of the characteristics of UWB

    technology and to assess the impact it may have on civil aviation. The FAA

    further states that all member organizations should be aware of this new

    technology and take appropriate action to ensure that aviation safety is not

    jeopardized if UWB is implemented78.

    FCCs View on Ultra Wideband Technology

    On May 10, 2000, the Commission adopted a proposal to consider permitting the

    operation of ultra-wideband (UWB) technology on an unlicensed basis. The FCC

    believed that UWB devices appeared to be able to operate on spectrum already

    77 Aviation Week, International Civil Aviation Authority Ultra Wideband Technology78 Aviation Week, International Civil Aviation Authority Ultra Wideband Technology

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    occupied by existing radio services without causing interference. Thus, it could

    permit scarce spectrum resources to be used more efficiently, a core

    responsibility of the Commission in its role as the nations spectrum manager.

    The FCC did understand and appreciate the useful implications of the use of

    UWB. In their report, they stated that recent advances in UWB technology have

    resulted in its potential use for a variety of applications such as radar imaging of

    objects buried under the ground or behind walls or hidden flaws in airport

    runways or highways and short-range, high-speed data transmissions suitable for

    broadband access to the Internet. Other radar systems could be used as fluid

    level sensors in difficult-to-measure situations such as oil refinery tanks and other

    storage tanks. UWB communications devices can also be used by police, fire

    and rescue personnel to provide covert secure communications and to detect

    people hidden behind walls or covered with debris, such as from an earthquake.

    UWB devices can be used for a variety of communications applications involving

    the transmission of very high data rates over short distances without interference.

    Such devices can be used to distribute wirelessly services such as phone, cable

    and computer networking throughout a building or home79.

    In its consideration of proposals for the authorization of UWB technology, the

    Commission has committed to ensuring that safety services, such as the Global

    Positioning System (GPS), are protected against harmful interference. To ensure

    79 Communications Convergence.com, FCC Consideration of Ultra Wideband Technology, Available at

    http://www.cconvergence.com/article/COM20020215S0001 (visited on 10/03/2001)

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    this protection, the Commission noted that further testing and analysis would be

    needed before UWB technology could be authorized to operate in the bands

    used for these services. The Commission stressed, in particular, the need for

    further testing and analysis in bands below 2 GHz. It said such testing is already

    being planned by a number of organizations, including the Department of

    Transportation and the National Telecommunications Information Administration.

    The Commission noted that it would provide ample opportunity to complete these

    tests and ensure that the analysis of the test results are submitted in the record

    for public comment before adopting any final rules

    80

    .

    More recently, the FCC just voted on and passed an authorization to remove the

    cap on the amount of spectrum owned by any particular service or carrier. This

    would probably be another step in the direction of allowing the widespread use of

    Ultra Wideband technology.

    80 Ibid

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    6. Regulatory Policy for Ultra Wideband Technology

    The existing rules for unlicensed devices were developed for devices using

    conventional narrowband technology and did not address UWB devices.

    Paragraph 15.209 of Volume 47 of the Code of Federal Regulations establishes

    the rules for the radiated emission limits of devices that can be authorized as

    unlicensed intentional radiators. Intentional radiating unlicensed devices are not

    permitted to transmit signals in any of the 64 restricted bands, which occupy a

    total of 13.283 GHz of the spectrum between 90 kHz and 36.5 GHz, because of

    potentially harmful effects to critical radio services operating in them. Although

    UWB device output powers are often low enough to operate under these

    regulations, their bandwidths are so wide that most emit portions of their signal

    within the restricted bands. Moreover, operation of many proposed UWB devices

    under current Part 15 rules was made difficult because they used to seek to

    operate with much higher peak powers than the rules permitted. Revision of the

    current rules was required before UWB devices, as must be the case with any

    new system or technology, whether licensed or unlicensed, could be

    accommodated compatibly with existing systems in the electromagnetic

    environment81.

    81 Spectrum Management Program, Regulations for use of Ultra Wideband Technology, Available at

    http://cio.doe.gov/spectrum/UWBregs.htm (visited on 02/15/2002)

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    NTIA and the FCC are working closely with both the UWB community and the

    operators of conventional radio communication equipment they authorize and

    license, to identify under what conditions UWB devices can operate without

    causing unacceptable interference to authorized and licensed radio services. To

    this end, the FCC initiated a formal proceeding that has included a Notice of

    Inquiry to gather information from the interested parties on UWB devices and

    their potential impact on conventional devices and a Notice of Proposed

    Rulemaking to examine proposed rules for the regulation of UWB devices. NTIA,

    meanwhile, has conducted a series of measurements and analyses for

    characterizing and assessing the impact of UWB devices on selected Federal

    equipment operating between 400 and 6000 MHz, which includes 18 bands and

    a total of 2502.7 MHz of restricted spectrum. The results include practical

    methods for characterizing UWB systems and providing the information needed

    to estimate or measure their potential to interfere with existing radio

    communications or sensing systems82.

    This report shows that operation of UWB devices is feasible in portions of the

    spectrum between about 3.1 and 5.650 GHz at heights of about 2 meters with

    some operating constraints. UWB operations at greater heights between 3.1 and

    5.650 GHz and near low elevation angle 4 GHz FSS earth stations may have to

    be constrained with respect to such factors as spectral output power, amount of

    operating time, and quantity of units operating in any area. Operations of UWB

    devices below 3.1 GHz will be quite challenging and any policy developed

    82

    Spectrum Management Program, Regulations for use of Ultra Wideband Technology

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    needed to consider the results of the analyses of interactions of GPS and UWB

    systems underway at NTIA and other facilities. While the study showed that

    aggregate UWB interference could be a significant factor to receiving systems

    under ideal propagation conditions, a number of mitigating factors were also to

    be taken into account to reduce or eliminate these aggregate affects83.

    Any radio frequency use must be authorized by either the National

    Telecommunications and Information Administration (NTIA) or the Federal

    Communications Commission (FCC) prior to operation. NTIA regulation for

    determining whether a radio station is under the control of the Federal

    Government, and thus must be authorized by NTIA, is contained in Section

    8.2.17 of the NTIA Manual of Regulations and Procedures for Federal Radio

    Frequency Management (NTIA Manual). NTIA regulations require that Federal

    agencies first obtain approval for major spectrum systems from NTIA, prior to

    submitting a request to the Frequency Assignment Subcommittee (FAS)84.

    On February 14, 2002, the Federal Communication Commission (FCC) adopted

    a First Report and Order that permitted the marketing and operation of certain

    types of new products incorporating ultra-wideband technology. They claimed

    that UWB technology holds great promise for a vast array of new applications

    that have the potential to provide significant benefits for public safety, businesses

    and consumers in a variety of applications such as radar imagin