Wiggins, LaQuita December 2006 DTEC 6810 Ultra-wideband Technology: Catholic University of America, The Revolution is Here Gerald F. Ross and K.W. Robins at Sperry Rand Corporation, and ABSTRACT Paul van Etten at the United States Air Force (USAF) Rome Ultra-wideband is a radio Air Development Center. The technology that has been technology was restricted to explored since the early 1960’s. military and Department of With new regulations and Defense applications from the technological advancements it is 1960’s to the 1990’s. In 1989 now poised for used in the Department of Defense advanced communications and coined the term ultra-wideband radar applications. [1]. The 2003 FCC ruling releasing the 3.6-10.1 GHz bandwidth at the noise floor [2], Ultra-wideband (UWB) is along with advances in an emerging wireless radio microprocessing and fast technology. UWB gains its switching in semiconductor name from its operation over a technology have transformed wide range of frequency UWB into a promising spectrum, greater than 500 MHz technology with a myriad of or 20% of the center frequency possible uses. according to FCC and ITU-R definitions. This vast bandwidth UWB Systems Technical is used instantaneously by low Details power, ultra short-pulses to carry information. UWB can be divided into Technological advances, new two main implementations: regulations, the unique impulse UWB (I-UWB) and properties of UWB signals multicarrier UWB (MC-UWB). I- combine to catapult this UWB is a single band technology in revolutionary implementation that using ultra- communications and radar short pulses to convey applications. information across the entire available spectrum. MC-UWB is History of UWB a multiband implementation that uses multiple simultaneous As with most technology, carriers [3]. I will now briefly there are many and overlapping discuss the most prominent origins. UWB as we know it implementation of each form. today can be traced back to the work of several groups in the 1960s, Henning F. Harmuth at Wiggins, LaQuita December 2006 DTEC 6810 Direct-Sequence UWB 480 Mbps. Devices have a range of up 20 m and transmit DS-UWB is a single band powers range from 15 µW while implementation. A single pulse in sleep mode to 145 mW at representing data is sent over 480 Mbps [6]. the entire spectrum. BPSK modulation, time domain signal Advantages and processing and DSSS Disadvantages of UWB techniques and RAKE receivers are used [4]. These pulses may The ultra-short occur in one of two spectra, 3.1 waveforms, in the nanoscale GHz - 4.85 GHz or 6.2 GHz - 9.7 range, that UWB systems use GHz. Depending on the offer several advantages. They parameters selected, DS-UWB offer the enhanced ability to radios can achieve a data rate penetrate through obstacles, between 55 Mbps to 1.32 Gbps opening up possible uses such in the 3.1 GHz band, or 55 Mbps as radar imaging. They have to 2 Gbps in the 6.2 GHz band. fine precision ranging at the DS-UWB devices have a 10 m or centimeter level opening up better range in multipath possible uses such as environments for 110 Mbps and positioning and tracking. They a total transmit power of about have the potential for high data 1/10 mW [5]. rates in multi-user networks opening up possible uses such MB-OFDM UWB as high speed networking. Transmitting in short pulses Multi-Band Orthogonal decreases interference because Frequency Division Multiplexing the signals do not last long is a multiband implementation. enough to interfere with other The spectrum from 3.1 GHz to signals. Ultra-short UWB waves 10.6 Ghz is divided into 14 also require limited processing bands, each with a 528 MHz power. The use of low power bandwidth. Each band has 110 waves allow UWB systems to subcarriers. Information working in tandem with existing carrying signals hop across the systems and makes them bands every 312.5 ns, with a difficult to intercept. UWB 9.5 ns guard in-between hops. signals have a resistant to QPSK modulation and time- jamming because of the vast domain and frequency-domain range of frequencies used by processing in the receiver are UWB. UWB systems are used. MB-OFDM supports data potentially low-cost because rates of 53.3 Mbps, 80 Mbps, they use carrierless 106.7 Mbps, 160 Mbps, 200 transmissions which mean they Mbps, 320 Mbps, 400 Mbps and can be designed with simple Wiggins, LaQuita December 2006 DTEC 6810 hardware or nearly all digital. UWB receivers are subject In addition, a single system can to long synchronization times be adapted to multiple uses, and must be complex enough to from communications to radar handle the multipath rich and positioning. channels inherent to the short UWB systems have pulse signals used by UWB considerable real and possible systems. UWB antennas also disadvantages that must be pose an engineering challenge addressed in order to build real- due to the unique demands and world applications. UWB shares challenges of UWB systems. a wide swath of bandwidth with Carrierless systems must rely other RF technologies, which on complex signal processing means there is potential techniques to recover data from interference, both from and to noisy environments. Channel existing systems (See Table 1). characterization, an essential part of communications systems Systems Possibly Degraded by Ultra design, is difficult in UWB Wideband systems because of wide Name Frequency bandwidth and reduced signal Distance Measuring energy [7] [8]. Equipment
● Airborne receivers 960-1215 MHz ● Ground transponders 1025-1150 MHz Regulation and Standardization Air Traffic Control Radio Beacon System ● Ground receivers 1090 MHz In addition to physical ● Airborne transponders 1030 MHz limitations, UWB faces many Air Route Surveillance 1240-1400 MHz regulatory hurdles related to Radar licensing. The FCC allocated Search and Rescue 1544-1545 MHz Satellite Land User spectrum for UWB in 2002 along Terminals with power limitations that Airport Surveillance 2700-2900 MHz influence UWB system design. Radar The FCC allows UWB Next Generation 2700-3000 MHz communication in the 3.1 to Weather Radar 10.6 GHz band, with a -10 dB bandwidth greater than 500 Maritime 2900-3100 MHz Radionavigation Radar MHz, and a maximum equivalent isotropic radiated Global Positioning power (EIRP) spectral density of Satellite Receivers -41.3 dBm/Mhz. The timeline in Link 1 1575 +/- 12 MHz Figure 1 outlines the progress of Link 2 1227 +/- 12 MHz FCC regulations. The European Link 5 1176 +/- 12 MHz Communications Committee and Japanese regulatory bodies both Table 1 released regulations earlier this Wiggins, LaQuita December 2006 DTEC 6810
Figure 1
year. Technology is expected to agreed upon, TG3a called it take off faster in the US quits and dissolved without because Japan and Europe agreeing on a standard in require interference mitigation January 2006. The two groups schemes referred to as detect promised to continue to grow and avoid (DAA). DAA and the UWB market; ironically, other developing specifications many think the dissolution of will remain a factor in UWB TG3a will speed up the development. development of UWB products. Standards battles also WiMedia Alliance supported MB- threaten UWB technology. Two OFDM was standardized by opposing groups began battling international standards group on the best implementation ECMA in December 2005 and is shortly after the FCC first expected to be standardized by allocated unlicensed spectrum ISO very soon. In addition, for UWB, single band or Bluetooth SIG has selected MB- multiband. In January 2003 the OFDM. The UWB Forum IEEE formed the IEEE 802.15.3a continues to support DS-UWB. task group (TG3a) to define the We can expect products on the physical layer for high data rate market from both groups this short range applications. The year. group’s biggest success IEEE 802.15.4a, a task occurred in a May 2003 meeting group for low data rate short when it narrowed down 23 range applications is also physical specifications into two considering a version of I-UWB. proposals: MB-OFDM UWB, supported by the WiMedia Applications Alliance, and DS-UWB supported by the UWB Forum. After two As mentioned earlier, and a half years of trying to UWB has many communications reach a standard both groups and radars applications. Wiggins, LaQuita December 2006 DTEC 6810 Engineers are challenged to market to determine which one create products that balance of these technologies dominates high data rates, low power wireless USB [9]. demands, performance and High speed Bluetooth is cost. In communications another budding UWB WPAN. It various WPAN implementations, will use WiMedia UWB with the such as wireless USB, are most promise of reaching multimedia promising. Each of the major speeds. Imagine downloading players in the UWB game have hundreds of photos in seconds their own implementation, or wirelessly downloading Belkin CableFree USB, which movies from an airport kiosk. Freescale Semiconductor and its Expect market entry in 2008. partners promote, and Certified Ultra Vision Security Wireless USB, which the Systems is leading UWB product WiMedia Alliance and the USB development in the search and Implementers Forum (USB-IF) rescue realm. Its portable promote. CableFree USB units LifeLocater system has were shipped in July 2006, stationary sensors that use UWB coincidentally these were also signals to detect moving the first UWB products objects. It can detect and introduced into the US market. locate motion, even breathing, In September 2006 USB-IF through debris and dense announced a certification materials in as little as 30 program, allowing seconds. The use of UWB manufacturers to gain signals gives this system better certification by building products object penetration, motion to its specifications. Products resolution, and distance should hit the market soon. measurement [10]. Both groups aim to replace the The 2006 Mercedes S- USB cable by providing secure Class uses 24 GHz short range high speed, short range UWB radar as part of its driver communications, like USB but assistant systems. Elapsed time without the cables. Data rates of pulsed signals is used to of 480 Mbps should be reached detect objects within 0.2 to 30 at distances up to 30 feet. m. It can detect and track up to Unfortunately CableFree devices 10 objects with a range and Certified Wireless USB accuracy of 7.5 cm [11]. devices cannot communicate LifeWave has developed a with each other. Surprisingly, patent pending UWB medical this hurdle for UWB technology radar. UWB signals are is not to be blamed on the transmitted into the body and different radio implementations reflected off of tissues and each uses, but on protocol organs. Signal processing is differences. We can expect the used to determine information Wiggins, LaQuita December 2006 DTEC 6810 about tissue size, location and communications: Pioneers and innovators” in Proc. Progress in movement. The images gained Electromagnetics Symposium, are not distorted by bone and Cambridge, MA 2000. 2. L. Yang and G.B. Giannakis, “Ultra- air cavities such as the lungs as wideband communications: an idea in other imaging systems. whose time has come” in IEEE Signal Processing Mag., vol 21, no. 6, pp. 26- Direct skin contact is not 54, Nov. 2004. required and information can be 3. J.H. Reed, Introduction to Ultra Wideband Communications Systems. collected through clothes and New Jersey: Prentice Hall PTR, 2005. bedding. The radar will be 4. F. Nekoogar, Introduction to Ultra Wideband Communication: inexpensive and low power, Fundamentals and Applications. New making it ideal for portable Jersey: Prentice Hall PTR, 2005. 5. “IEEE 802.15.3a Updated DS-UWB applications [12]. Proposal Specification”, IEEE 802.15 Working Group for WPANs, July 2004. 6. ECMA, [4] ECMA, "Standard ECMA- The Future 368:High Rate Ultra Wideband PHY and MAC Standard," Dec. 2005, [Online]:http://www.ecma- Home audio systems and international.org/publications/standards PCs without the confusing and /Ecma-368.htm. 7. L.E. Miller, “Why UWB? A Review of messy cables and even more Ultra Wideband Technology” April 2003. tech savvy cell phones are the [Online]:http://www.antd.nist.gov/wctg /manet/NIST_UWB_Report_April03.pdf promise of UWB. Some people 8. D. Iyengar, “Understanding ultra question whether UWB really wideband technology: Advantages, applications, and regulatory policy,” will impact consumer life. A M.A. Thesis, Tufts University, May better question is when? There 2002. 9. R.A. Quinnell, “Clash of the wireless- is a definite demand for the USB standards” in EDN, September 1, applications that can be 2006. [Online]: http://www.edn.com/index.asp?layout developed using UWB. UWB =article&articleid=CA6363903&spacede also has a unique edge over sc=features 10. UltraVision Security Systems, Inc. 10 competing technologies in its December 2006. < low cost and low power model. http://www.ultravisionsecurity.com/> 11. J. Wenger, “Automotive radar-status Unfortunately early regulatory and perspectives” in Compound division has split UWB Semiconductor Integrated Circuit Symposium, 2005. implementers down the middle. 12. LifeWave. 10 December 2006. Countries around the world
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