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A.~.3 Wireless Communication Wireless communication has significant ITS applications: 1. Any vehicle-to-infrastructure communication (i.e., mobile applications) 2. Temporary communication faciiides including rapid deployment when required 3. Cations where wire or fiber are not options: a. canyon, ever, other geographic obstacles b. Business or traffic disruptions for installation are unacceptable 4. Situations where more cost effective Han wire or fiber 5. Diversity~ot-standby for reliability Wireless offers bandwidths and bit rate capabilities comparable to wire and, to a lesser extent, to fiber. Vanous wireless options are available to support virtually any llS link, including low- speed local links, high-speed backbones, and TOC-to-TOC links. Wireless communication has unique characteristics compared win wire and fiber: 1. Wireless communication requires installation of only terminal equipment. In addition, up to Me repeaterless propagation limits of We installation, has fixed (constant) cost per link regardless of distance, compared USA fiber/wire which must include approximate linear cost/un~t of distance. This comparison is depicted in Figure A.13-~. Ri~t-of-way~site acquisition costs are only incurred at terminal locations, not between as with fiber/wire. 2. Wireless requires FCC licensing for guaranteed interference-free operation or careful design/operation considerations in Be unlicensed bands. L:W~h~c2~t N~3-51e P~2F~Re~n A1-124

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r 3. Wireless propagation and coverage characteristics vary widely based on frequency, antenna heights, intervening terrain, weaker, allowable power, etc., which makes design of wireless systems more complex than wire or fiber design. Wireless, like fiber and wire, has link budget criteria for successful operations. Table A.~.3 lists typical wireless little parameters. Because wireless has different propagation modes and widely varying weaker, atmospheric, terrain, etc., lim~tabons, repeaterIess distances and achievable bit rates are highly vanable. Table A.~.3 Typical Wireless Link Budge! Parameters I Parameter T Example Transmit Power | 50,000 WaNsAM Broadcast Stat on (77 dbm) Transmission Loss* -6 dB/Octave Free Space (Octave is double the distance) -6too18dB/Octave inMultipath Receiver Sensitivity -80 to -120 dam *Actual Transmission Loss is highly variable depending on many factors as discussed In text. A.~.3.! Wireless Propagation and Coverage At Me most fi~nd~mental level, wireless propagation and coverage can be modeled by He free space transmission (i.e. Line of Sight propagation) formula (Equation A.~.3.~-~) (adapted from lakes, Microwave Mobile Communications). LW~h~2.~t NC~3-51e P0e2F~Re~n A1-126

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Equation A.1.3.1-1 Pr = Pt (4 d) g&, or Pr ~ ,1 2 L = - = if_ gtgr where: L = pad loss P. = Receive Power P'= Transmit Power A = wavelength = c - 10 "meters /see d = distance between g2. = gain of transmit antenna gr = gain of recede antenna c = speed of light, f = frequency transmit Id receive antennas For an antenna that receives or transmits equally In all directions over a sphere, grge = I. This is generally referred to as an isotropic antenna Needless to say, directional antennae are frequently employed to Improve wireless system performance. Equation A.~.3.~-1 is often converted to Lab (]OSS expressed in decibel or dB) with antenna gates, gigs = I, and the loss equivalently expressed as: c Equation A.1.3.1-2 LdB = - 92.4 - 20 x log ~.O(fGNz) ~ 20 X log ~o~dk,,') In free space line-of-sight propagation, Here is a loss of 6 dB for each doubling of distance and 6 dB per doubling of frequency. Thus, propagation distance, or coverage, is less at higher frequencies (assuming all other factors are equal). Free space (or spaces) propagation is usually only consistently achieved in outer space, although many earthbound applications under favorable conditions, closely approximate free space propagation. Generally, actual propagation losses are more severe Man free space and must be modeled (usually stadshcally) accordingly. Free space propagation is typically "line-of-sight," t.:\.NCHRP`.Phase2.rp~ NCHRP 3-51 Phase 2 Ftnal Report A1-127

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but may include refraction (i.e., sometimes creating multiparty), and some diffraction over terrain or obstacles (e.g., buildings). Free space propagation occurs at all RF frequencies and is dominant at hider frequencies. Another mode of propagation is ground (or surface) wave propagation which is the dominant component at frequencies less than 2 megahertz. This is a secondary component up to He very high frequency range (30-300 MHz) and can usually be neglected at frequencies above 300 MHz. Ground waves usually combine with direct (free space) signals and other reflected signals in a manner such Hat He received signal has greater attenuation Han a free space signal; however, at very low-frequencies, ground waves dominate and therefore are used by the rnilit.ary for worldwide commun~cabon with submarines and for other cndcal missions. Propagation is very good at these low frequencies and literacy provides worldwide communication. The AM broadcast band propagates via ground waves (as wed as other modes). Skywaves, another mode of propagation, is the bending of a wave as it passes from one medium to another because of different propagation speeds in He two mediums. This bending causes radiowaves Hat would normally propagate into space to bend back toward He earn. This bending typically occurs in the ionosphere region which is approximately 30 to 260 miles above the earths surface. Depending on He frequency employed, time-of-day (night is best), plus other factors; skywave propagation can support communication link distances from 60 to over 6000 miles. Skywave propagation is the dominant mode of propagation in the 2 to 30 MHz frequency range. Figure A.~.3.~-1 illustrates these modes of propagation. Propagation characteristics are highly dependent on frequency and can be classified into frequency bands with each band having essentially similar propagation charactenstics. Table A.~.3.~-! lists the generally accepted frequency band cIassificabons, range of frequencies, propagation characteristics, and typical uses. ~;\NC~Phasc~rp ~NCHRP 3-51 Phase 2 final }report A1-128

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In RF (wireless) system design, coverage is estimated based on propagation loss between transmitting and receiving antennae. For frequency reuse based on geographic separation, signal attenuation of a potential interfering transmitter due to propagation loss at a receiving antenna must be sufficient so that the interfering signal level is significantly less Can the desired signal. Obviously, at lower frequencies that support over-the-honzon propagation modes such as groundwave and skywave, frequency reuse distances will be great. Conversely, LOS propagation to the horizon, which is the dominant propagation mode above 30 MHz, permits much shorter frequency reuse distances and smaller direct coverage areas, but greater system capacity through frequency reuse. In addition to slywave, ground/surfacewave, and free space LOS propagation modes, over factors influence propagation: 1) In free space propagation, multipath attenuation, (where reflected and direct signals combine) can be greater or less. A typical multiparty loss profile is depicted in Figure A.~.3.~-2. Up to a distance prior to onset of multiparty, the loss profile is He typical 6 dB/km and Hereafter has a steeper loss profile greater Han 6 dB/km. Under more severe multipath conditions, multiple breakpoints may exist with successively steeper loss per unit Of distance. Multiparty is a dominant factor in mobile wireless communication (e.g., cellular, unlicensed spread spectrum). 2) Above VHF, traditional suggests theory is that propagation is limited to He LOS honzon. Experience, often He result of unexpected interference, has proven overwise. Current theory suggests that weaker produces venous select conditions Hat actually enhance propagation. These conditions include tropospheric scatter, rain scatter, dusting, radiation inversion, reflection from objects, etc. When these conditions anse, propagation can extend significantly beyond LOS. These conditions can occur virtually anywhere, but seem to be most prevalent over wann water areas such as Florida, He Gulf Coast, and California, In He U.S. These conditions also often create undesired interference; however, RF communication propagation engineers usually understand local conditions and often have mesons to address these problems and/or use to their advantage. L:~h=~.~t NC^P3^51 P~e2F~Re ~A1-131

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Wireless propagation modeling and design is not an exact science. Many variables exist so detailed RF propagation and coverage design should be accomplished by communication engineers who have access to many models. Rough planning estimates, however, can be calculated using the free space model of Equation 1, modified as appropriate, by Me actual antenna gain. A.~.3.2 FCC Rules RF spectrum for wireless communicators is a scarce resource ~at, except for some unlicensed bands, is allocated to service providers and/or users on exclusive or shared bases, though licensing administered by the Federal Communications Commission (FCC). The mles governing licensed and unlicensed wireless operations are contained in the Code of Federal Regulations (CFEt) Title 47, Telecommunications, consisting of parts 0 Trough 101 (currently). Table A.1.3.2-1 lists Me parts of CFR 47 relevant to ITS. Their titles provide an indication of the services addressed. Table A.1.3.2-2 provides more detail on some of the Parts significant to ITS and includes services, comments, pending FCC Notices of Proposed Rule Malting (NPRM) and Reports and Orders wig ITS impact, and ITS applications. A. l.3.2. ~ FCC Licensing and Coordination FCC licensing procedures and rules are generally described in Part ~ of CRF 47. These procedures and rules are complicated, partly because of many years of evolution and upgrade. This section is not intended to be an in-depth discussion of the details of licensing and coordination, but a general overview of Me concepts of Importance to ITS. FCC licenses/au~onzations may be required in the following situations: I) Operator/station license to operate a transmitter at a given site or within a specified geographic area L~\NCHRP\Phas~p' NCHRP 3-51 Phase 2 Final Report A1-133

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Table A.~.3.2-1 Code of Federal Regulation (CFR) 47 ~ Telecommunications Parts Relevant to ITS FCC Part (partial list of Communication Organization relevant parts) Part 1 Practice and Procedures Part 2 Frequency Allocations and radio treaty matters; general rules and regulations Part 5 Experimental radio service (other than broadcast) Part 13 Commercial radio operator Part 15 Radio Frequency devices Part 17 Construction, marking, and lighting of antenna structures Part 18 Industrial, scientific, and medical, devices (ISM) Part 21 Domestic public fixed radio services Part 22 Public mobile services Part 23 International fixed public radio communications see/ices . _ Part 25 Satellite communications Part 68 Connections of terminal equipment to the telephone network Part 73 Radio broadcast services Part 74 Experimental, auxiliary, and special broadcast and program distributional services Part 76 Cable television services . Part 79 Cable television relay service Part 80 Stations in the maritime services Part 87 Aviation services Part 90 Private land mobile radio services Part 94 Private operational-fixed microwave services Part 95 Personal Radio services Part 97 Amateur radio services .. Part 99 ~ Part 100 Direct broadcast satellite service . . . . Part 101 Terrestrial Microwave Fixed Radio Services (will replace Part 94 and Parts of Part 21) L:\NCHRP\Phase2~pt NCHRP 3-51 ~ Phase 2 Fmal Report A1-134

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Table A.1.3.5.1-1 lists the selected amended Part 90 frequency bands including the refarm~ng bands as well as others. Included In the table are channel spacings and au~onzed channel bandwidths. As opposed to requ~nng users to upgrade, He new rules encourage upgrade over an anticipated lO-year nonnal replacement cycle by not type accepting new equipment for the refanning bands unless it meets He new rules. After August I, 1996, type acceptance win be granted only if one of He following is met: Single or multimode equipment with a maximum banded of 12.5 kHz; 25 MHz of bandwidth for multimode equipment that is also capable of operating on channels of 12.5 kHz or less; or 25 kHz bandwidth operation equipment is permitted by employing spectrum efficiency standards of at least one voice channel per 12.5 kHz of bandwidth or data channel operations supporting at least 4800 bps per 6.25 kHz of bandwidth (i.e., .768 bits/second/hertz). This will permit spectral efficient TDMA equipment to be deployed. On January 1, 2005 the spectral efficiency requirements win be reduced from 12.5 to 6.25 kHz. The refarniing order contains a Further Notice of Proposed Rulemaldug (FNPRM) to consolidate frequency coordination. Currently, the refanning bands are divided into 20 services for He purposes of frequency coordination. These current services are listed in Table A.~.3.5.~-2, as: The number of transmitters as of December, 1994; \ The number of assigned 25 kHz channels (some channels are shared by different services in both the Vim and UHF bands); and The frequency coordinator. It should be noted that this definition of services for frequency coordination purposes is close, but not the same, as the definition of services under Subparts B. C, D, and E (see Table A.~.3.5-~. The FNPRM directs He PLUM users community to assess their needs and submit a consensus L:~h~.~t NC~3-51 Ph~2F~Re~n A1-179

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Table A.~.3.5.~-1 Amended Part 90, PROS Standard Channel Spacing/Bandwidth . Frequency Band (MHz) Channel Spacing (kHz) Authorized Bandwidth (kHz) 25 - 50 ~20 ~20 72 - 76 20 20 150 - 174 1 (25 kHz) 7.52 25/11.25/623 220 - 222 5 4 421 - 430 (25 kHz) 6.52 25/11.25/623 . 450 - 470 1 (25 kHz) 6.52 1 25/11.25/6~3 470 - 512 1 (25 kHz) 6.52 1 25/11.25/623 806 - 821/851-866 1 25 20 ._ . 821 - 824/866 - 869 1 12.5 1 20 896 - 901/935 - 940 12.5 13 0 929 - 930 1 25 1 20 proposal within Free months of He effective date of Be Report and Order on how to consolidate frequency coordination arid create a consolidated real-dine database of assigned frequencies. The FNP~M cites a goal of 24 coordination categories based on Me user proposal justifiable categones. The reasons for Me consolidation are: More efficient and effective frequency assignments among low and high use groups; Simplify interservice shanng; 2 Prior to August 16, 1995. For stations authorized on or after August 16, 1995, type acceptance of equipment after August 16, 1996 must be capable of operating on channel bandwidths of 12.5 klIz or less and support one voice channel per 12.5 kHz of bandwidth and a minimum data rate of 4800 bps per 6.25 Adz of bandwidth (i.e. about .768 b/s}Hz). 3 Multimode capable of operating on He old 25 kHz and He new channel spacing/bandwid~ can be type accepted after August 1, 1996 .~NCHRP\.Phase:.rp ~NCHRP 3-51 Phase 2 Penal Report Al-180

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Table A.~.3.5.~-2 Private Land Mobile Radio Services and Frequency Coordinators Description of Private Land Mobile Radio Services Below 470 MHz Number of Number of Frequency Transmitters Channels Coordinator (see list below) VHF UHF 3,575,223 109 289 NABER(PCIA) 1,550,394 75 86 APCO 1,382,647 80 78 APCO 843,747 815 30 ITA 826,773 38 48 IMSA 768,551 40 UTC 742,454 119 20 MR 419,436 19 74 IMSAIIAFC NABER(PCIA) 356,607 58 38 MSHTO .. 340,913 103 36 PFCC of API 335,109 43 38 MSHTO 308,227 52 48 MRFAC 182,598 56 30 ATA 137,640 10 36 TELFAC 123,864 36 24 ITLA Business: educational, religious, hospital, small business, etc. Police: protection of citizens in emergency and non-emergency situations Local Government: official functions of governmental activities Special Industrial: heavy construction (roads/bridges), farming, and mining Fire: fire protection services by state and local entities Power: electricity, natural or manufactured gas, water, and steam Railroad: rail transport of passengers and freight Special Emergency protection of life and property for emergency medical care Forestry Conservation: protection and conservation of forests and wildlife Petroleum: production, collection, and refining petroleum products by pipeline Highway construction and maintenance of highway activities Manufacturers: plants, factories, mills, and shipyards Motor Carrier: trucking (short and long haul) and public buses Telephone Maintenance: daily repair and emergency restoration Taxi Cabs: nonscheduled passenger land transportation L.\NCHR~Phasc2.rpt NCHRP 3-51 Phase 2 Final Report A1-181

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Description of Private Land Mobile Number of Number of Frequency Radio Services Below 470 MHz Transmitters Channels Coordinator (see list below) VHF ~ UHF Forest Products: logging,hauling,and ~119,428 | 106 | 50 | FIT l manufacturing of lumber products Automobile Emergency: dispatching of 35~877 23 4 MA repair trucks, tow trucks, etc. Relay Press: publication and operation of 22,017 12 4 AN PA newspaper and press Video Production: producing, 12,794 18 O AMPTP videotaping, filming of movies and television programs l l l l l Totals: 20 Radio Services (includes 553 324 EMRS) I 12,084,299 1 1 1 1 AAA Amencan Automobile Association AASHTO American Association of State Highway and Transportation Officials AAR Association of Amencan Railroads AMPTP Alliance of Modon Picture and Television Producers ANPA AmencaD Newspaper Publishers Association APCO Association of Public Safety Communications Officials - International, Inc. API Amencan Petroleum Institute FIT Forest Industries Telecommunications LAFC International Association of Fire Chiefs IMSA International Municipal Signal Association ITA Industnal Telecommunications Association, Inc. 1TLA International Taxicab and Lively Association MRFAC Manufacturers Radio Frequency Advisory Committee NABER National Association of Business and Educational Radio (merged win PCIA) PCLA PFCC Personal Communications Industry Association Petroleum Frequency Coordinadng Committee TELFAC Telephone Maintenance Frequency Advisor Committee UTC L:\NCHRP\Ph;~se2.rpt Ublides Telecommunications Committee NCHRP 3-51 ~ Phase 2 final Report A1-182

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Organize channel allocation to more easily use advance technology; More effectively allocate He newly created channels; and Provide a mechanism for exclusive channel use of He expanded channel capacity. This urn also allow more efficient enlacing. If a consensus user proposal cannot be reached, the FCC says it win make a decision. Competing frequency coordination services will be allowed in each coordination category (or group). Refarming could have important ITS implications: Access to lower frequencies wad greater coverage potential. (This might be essential for rural applications.~; Substantially greater number of channels becoming available for new applications; Streamlined technical rules permitting more efficient trundling and TDMA. (Spread spectrum will be allowed, but only for police applications.~; It promotes interoperability with 12.5 kHz equipment used by Federal Government users (e.g., FBI, DOD), and He new APCU-25 standard developed by the public safety community; It promotes upgrades of existing PEMA systems (e.g., highway maintenance). (Some will require network reconfiguration due to new technical rules reducing maximum allowable powers and lower maximum antenna heights.~; and The data rate capacity of the channels ranges from 4,800 bps (6.25 kHz bandwidth) to 19,200 bps (25 Lutz bandwidth) at BERs between i0~3 and lo-6 . The ITS community needs to actively promote its needs during He transitional period. L:\NCHTWhase2.rpt NCHRP3-51e Phase2F'nalReport A1-183

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A.~.3.~.2 Transportation /nfrastruefure Radio Service {T/RSJ - AVW[MS ~ February, 1995, the FCC adopted rules (FCC 9541, February 5, 1995) for Automatic Vehicle Monitoring (AVM) under a new Subpart M stardng at Part 90.350. These new rules replace interim (1970) AVM rules in 90.239 (deleted). The title of Subpart M is "Transportation Infrastructure Radio Service" AIRS) and is intended to allow new radio-based technologies for ITS applications. The AVM name is changed to Location and Monitoring Service (LMS) and is Me first radio-based technology service under this subpart. The LMS will share spectrum in the 902-928 MHz band with over users (see Table A.~.3.4-~. The FCC 9541 Report and Order (R&O) modifies and eliminates outdated regulations that have not kept pace with technological evolution that is supportive of ITS applications. The key elements of Me R&O are as follows: Defined two general categories of EMS technologies multilateration, or w~deband Including direct sequence spread spectrum, and non-muldIateration, or narrowband. The subbands and ban dwid~s are in Table A.13.S.2~. Table A.~.3.5.2~1 EMS Frequency Subbands Subband(MHz) ~ System LicenseBandwidths tMHz) ~ Power(Watts) 902.00 - 904.00 Non-multilateration2.00 MHz 30 904.00 - 909.75 I Multilateration 5.75 MHz | 30 l 909.75 - 921.75 | Non-multilateration 12.00 MHz | 30 l 919.75 - 921.75 Both (shared equally) 2.00 MHz 30 921.75 - 927.25 1 Multilateration 5.75 MHz 1 30 927.25 - 928.00 i Multilateration (Forward links, 250 KHZ) | 300 Permit Multilateration LMS systems to locate any object (i.e., vehicle or not). In addition to locations and monitoring information, permit LMS systems to transmit about a mobile unit, status and instructional inflation including voice and non-voice. Under ~ :\NC~Whase2.rp ~NCHRP 3-51 Phase 2 Fmal Report Al-184

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certain conditions related to public safety or special emergency radio service, L`MS systems may interconnect with the Public Switched Network (PSN). Expand EMS license eligibility to all entices eligible under Part 90 and to allow licensees, under qualifying critena, to provide commercial service to paying subscnbers. Establish exclusive license for multilateration systems in Major Trading Areas (MTAs) Trough competitive bidding, but provide a mechanism for existing operators to godfather current licenses. License non-multilateration systems on a shared basis in designated subbands. Clarify what constitutes harmful interference from Part 15 device and amateur operations as defined In Part 90.361. (Basically, indoor operations and operations with low antenna heights win not be considered hannfill interference.) Make provisions for furler testing of muldlateradon systems to ensure that interference to Me existing, widely deployed, and expanding Part 15, unlicensed operation is minimized. These rules have been defined to accommodate various EMS services from multiple vendors. The multilaterabon, or wideband, licenses will support vehicle location using a broad band signal. Technically, a w~deband signal can be received with better time resolution (Time Resolution B0tdwid~ that can employ several techniques to accurately locate a signal source, typically a vehicle. Pulse ranging techniques are typically employed. Thus, LMS services will be available for: Vehicle location within approximately 50-200 feet depending on infrastructure and interviewing te~Ta~n/obstacles; Bit rates for voice/data from 1200 bps to in excess of 400,000 bps; and ~:\NCHRP`Phase~rp ~NCHRP 3-51 Phase 2 final Report Al-185

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If voice is not supported, packet technology can be employed and packet size can be tailored for short, efficient, location messages. Unlike GPS band location systems, these multilateration services can offer two-way and other communication and integrated fleet management, emergency, vehicle secunty, smart/probe, communication services. These EMS services should not be as susceptible as satellite to shadouang/facing in urban areas. Additionally, EMS services ability to integrate location and communication services should prove cost-effective when available. The non-multilateration cards, essentially narrowband, are intended for non-commercial applications and shared spectrum usage. Toll/RF tags are the best examples. Many of these applications can be implemented under the Part 15 unlicensed rules, but can increase power and achieve some interference protection benefits by licensing under Part 90. It should be emphasized that Part 90 EMS operations in 902-928 MHz band have primary status and Part 15, unlicensed, operation has secondary status. Thus, in Me event of interference, Part 15 applications must cease operation or change installation or configuration to eliminate interference. A. 1.3.5.3 Meteor Burst Communications the 1930s, researchers observed that ionized trails of meteors entering Me ear~'s atmosphere win reflect radio waves. In the 1940s and 1950s, much research was conducted on meteor burst propagation charactenstics. In Me 1950s and 1960s, as satellite technology emerged for '`beyond line-of-sight" communication, interest in meteor burst communication waved. Nevertheless, meteor burst communication has achieved cost effective application primarily in government sponsored remote sensor data collection. The U.S. Forestry Service has placed snow/weather sensors on remote western mountaintops to measure snow depths and melting to predict spring river~creek flow. This "SNOTEL" program uses meteor burst communication from remote mountaintop sites to communication hubs. The mutiny uses it as a backup to potentially vulnerable satellite long range links. Meteor burst technology is also employed for truck fleet management applications. ~:wCHRP`Phasc2.rps NCHRP3-51. Phase2FinaIReport A1-186

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The meteor burst communication channel phenomenon is illustrated in Figure A.~.3.53-~. When a meteor trail sweeps into the earths atmosphere and is properly oriented, the transmit signal is reflected to We receiver for as long as the trait persists. The occurrence of a properly oriented trail is a statistical phenomenon in both start time, total time of occurrence, and channel characteristics. This statistical nature makes meteor burst communication unsuited for tight real- time applications. Table A.~.3.5.3-1 illustrates typical parameters for meteor burst communication channels. The ITS applications for meteor burst focus on rural locations where data sources and destinations can be sparsely located over an extended- geographical area. The specific applications include: Automated weather stations; VMS; Non-real-time control data such as timing plans; Kiosk database updates (not remotely interactive); Non-real-time sensor data (monitored, but not control); and Fleet management (e.g., CVO, transit). ; L:\NCHRP\Phase2.rpt NIP 3-51 Pee 2 Fed Reed A1-187

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Table A.~.3.5.3~1 Typical Meteor Burst Communication Parameters Parameter | Value Coverage Distance 2000 km (1250 miles - maximum) Carrier Frequency 40- 100 MHz Transmit Power 200 - 2999 Watt Bandwidth 100 kHz Typical Bit Rates 1200- 19,200 bps(intermittent) Trail Duration 0.2 - 1.0 seconds Information Duty Cycle 2.5 - 5.0 percent . Average Message Delay 10 - 80 seconds . Worst Message Delay ~ ~ em_ The FCC rules for meteor burst are in 90.250 and only authorizes operations for the state of Alaska. Coterminous U.S. operation is by FCC developmental authorization defined in Subpart Q of Part 90. L:~h~.~t NCH~ 3-51 PI 2 Few Ream A1-189