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2.3 COVERAGE AREA AND SATELLITENETWORKS2.3.1 Geometric Coverage AreaClarke [2] foresaw in his 1945 article that it would be possible to providecomplete radio coverage of the world from just three satellites, provided thatthey could be precisely placed in geosynchronous orbit. Figure 2.5 demonstratesthis.The amount of coverage is an important feature in the design of earthobservation satellites. Coverage depends on altitude and look angles of theequipment, among several factors. To establish the geometric relationship ofthe coverage, we take a section of the satellites in Fig. 2.5 as an illustration.This section is redrawn as shown in Fig. 2.6.The maximum geometric coverage can then be defined as the portion ofthe earth within a cone of the satellite at its apex, which is tangential to theearth’s surface. Consider the angle of view from the satellite to the earthterminal as a; then the apex angle is 2a. The view angle has a mathematicalphysical function given by a ¼ sin 1 R e¼ sin 1 R eh 0 þ R erð2:13ÞFIGURE 2.5Complete coverage of the earth’s surface from three satellites.Copyright © 2002 by Marcel Dekker, Inc. All Rights Reserved.
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SatelliteCommunicationEngineeringMi
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This book is dedicated to my famili
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Because of the immense importance o
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means of a combination of applicati
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about my promise to my students, an
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2.3 Coverage Area and Satellite Net
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1Basic Principles of SatelliteCommu
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and voice (telephone) communication
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FIGURE 1.2Communication between two
Page 38: interpreting or uncovering the deci
Page 42: cryptographic keys K ti (where i ¼
Page 46: FIGURE 1.6Block ciphering technique
Page 50: FIGURE 1.7Part of block ciphering w
Page 54: Based on the ordering sequence of (
Page 58: TABLE 1.1 (continued )S612 1 10 15
Page 62: For an uncoded message x and the fe
Page 66: 2. Your task is to develop a commun
Page 70: FIGURE 2.1Geometry of a satellite.
Page 74: Future trends in satellite antennas
Page 78: In the United States, the three sat
Page 82: TABLE 2.3Typical Links Frequency Ba
Page 86: FIGURE 2.4Satellite period and orbi
Page 92: The apex angle required at the sate
Page 96: the frontline satellites is then pa
Page 100: station antenna must be pointed to
Page 104: and the azimuth angle is a z ¼ 180
Page 108: 2.5.3 Swath WidthThe width of the v
Page 112: 2.6.3 System Speci¢cations: Analys
Page 116: Like all materials that require cou
Page 120: By the first definition, the system
Page 124: SolutionFrom (2.28), we can estimat
Page 128: FIGURE 2.11An example of redundancy
Page 132: adiators. An antenna array is a fam
Page 136: Example 2.3: The earth subtends an
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eam is assumed symmetrical (i.e., y
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FIGURE 2.15Feed array elements ðy
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If the steering is in the direction
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2.8 SATELLITE POWER SYSTEMSA key co
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Calculate (1) the probability that
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FIGURE 2.20Carrier processing.infor
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FIGURE 2.22(d) elliptic.Types of ba
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FIGURE 2.23A klystron. (Courtesy of
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FIGURE 2.25A simple block diagram o
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tional protection is required to en
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3.1 BASIC PRINCIPLE OF EARTH STATIO
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3.1.1 Technical and Operational Req
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excellent protection against noise
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FIGURE 3.3QPSK modulator.FIGURE 3.4
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TABLE 3.28-PSK Truth TableInput bit
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FIGURE 3.8An M-ary PSK demodulator
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where B is the allocated channel ba
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A frequently used function is the Q
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In view of (3.11), Eq. (3.18) can b
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Encoder and DecoderAn encoder is an
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Modulator and DemodulatorA modulato
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Zero Forcing Technique. Suppose the
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The adjoint of matrix A is obtained
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FIGURE 3.14The three-tap equalizer
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First, in the case of digital signa
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than 1=A. Whichever law is used, th
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FIGURE 3.16Block diagram for estima
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3.4.2 Antenna TrackingAn earth stat
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controlling antenna pointing. The m
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FIGURE 3.19A generalized model of a
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FIGURE 3.20Entropy of a binary sour
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whereHðYÞ¼output entropy, the av
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To have a feel for this expression,
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2. The system’s overall condition
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transmitted down the fiber as digit
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10. Kantor, L. Y. (ed). (1987). Han
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142. Simulate the probability of bi
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FIGURE 4.1A simplex link.baseband c
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Chapter 2, Sec. 2.7, discusses that
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From (4.6), the received power P r
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FIGURE 4.3A model of the combined-l
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4.1.2 Rain AttenuationRain attenuat
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FIGURE 4.5rates.Average rainstorm p
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FIGURE 4.6Adjacent satellite interf
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FIGURE 4.8Satellite separation dist
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inability of satellite A to accurat
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FIGURE 4.10 Cross-link E b =N 0 vs.
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Then using (4.41), the overall C=N
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(iv)(v)(vi)(vii)Calculate the recei
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5Communication Networks andSystemsC
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discriminate among carriers by temp
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FIGURE 5.2 Principle of FDMA system
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FIGURE 5.3 Operational concept of T
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FIGURE 5.5TDMA: bit rate r b for 1
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Copyright © 2002 by Marcel Dekker,
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5.2 CAPACITY COMPARISON OFMULTIPLE-
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Rearranging (5.11) in terms of ener
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The transmission bit rate isR r ¼
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6Error Detection and CorrectionCodi
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the channel and reconstruct the sou
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message sequence X . Thus, a system
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If we consider a message X ¼ð1010
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can be seen in Table 6.1 that the m
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FIGURE 6.1A (7, 4) cyclic code gene
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FIGURE 6.2Convolutional codes encod
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Alternative methods of describing a
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FIGURE 6.5 Code tree diagram of Fig
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FIGURE 6.8 Code tree diagram of rat
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consistent with the constraint leng
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trellis depth is approximated to 5L
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FIGURE P.1A convolutional coder.the
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7Regulatory Agencies andProceduresT
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of the radiofrequency spectrum, and
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The CCIR works through the medium o
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7.1.3 IFRBThe International Frequen
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The national or regional spectrum m
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3. The need to expand or enhance th
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The DSP will be responsible for res
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2. Provide a convenient framework w
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FIGURE 8.3Types of user-to-network
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H1-channels are designed to carry v
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information. The transfer cell prov
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The OSI layers are divided into two
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plane is denoted by U, the control
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interfacing, maintenance, and conne
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adjoining base station to scan the
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FIGURE 8.9Geometry of a polygon.The
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FIGURE 8.11Splitting cells into sma
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causes signal fading. Of course, th
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FIGURE 8.14TCP=IP suite and its rel
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access to an Internet point of pres
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message security via satellite is d
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REFERENCES1. Wu, W.W. (1989). Eleme
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Appendix ANotationsThe symbols have
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N sPP rP sP TRRðtÞR cR eR rR vSS
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g Central anglez Channel gainZ Ante
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AttenuationBandwidthBearer serviceB
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Frequency divisionmultiple accessFr
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MultiplexingNetworkOmnidirectionala
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UplinkUser-to-networkinterfaceThe e
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