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cryptographic keys K ti (where i ¼ 1; 2; ...; n) shared between the communicatingearth stations while the satellite remains transparent: meaning thesatellite has no role in the ciphering process.A cryptosystem that may work for the scenario depicted by Fig. 1.4 isdescribed as follows. All the earth stations TS(i) and RS( j) are assumedcapable of generating random numbers RDN(i) and RDN( j), respectively.Each transmitting earth station TS(i) generates and stores the random numbersRDN(i). It then encrypts RDN(i), that is, E y ½RDNðiÞŠ, and transmits theencrypted random number E y ½RDNðiÞŠ to RS( j). The receiving earth stationRS( j) generates RDN( j) and performs modulo-2 (simply, mod-2) additionwith RDN(i); that is, RDNð jÞRDNðiÞ to obtain the session key K r ð jÞ,where denotes mod-2 addition. It should be noted that mod-2 addition isimplemented with exclusive-OR gates and obeys the ordinary rules of additionexcept that 1 1 ¼ 0.The transmitting earth station retrieves RDN(i) and performs mod-2addition with RDN( j) (that is, RDNðiÞRDNð jÞ) to obtain the session keyK t ðiÞ. This process is reversed if RSð jÞ transmits messages and TSðiÞ receives.Figure 1.5 demonstrates the case where the satellite plays an activeciphering role. In it the keys K Ei (where i ¼ 1; 2; ...; nÞ the satellite receivesfrom the transmitting uplink stations TS i are recognized by the onboardprocessor, which in turn arranges, ciphers, and distributes to the downlinkFIGURE 1.5Ciphering with keyed satellite onboard processors.Copyright © 2002 by Marcel Dekker, Inc. All Rights Reserved.
Page 2: SatelliteCommunicationEngineeringMi
Page 6: This book is dedicated to my famili
Page 10: Because of the immense importance o
Page 14: means of a combination of applicati
Page 18: about my promise to my students, an
Page 22: 2.3 Coverage Area and Satellite Net
Page 26: 1Basic Principles of SatelliteCommu
Page 30: and voice (telephone) communication
Page 34: FIGURE 1.2Communication between two
Page 38: interpreting or uncovering the deci
Page 44: earthstations, RS( j) (more issaid
Page 48: Technology developed an advanced en
Page 52: FIGURE 1.8Sequence of the transform
Page 56: TABLE 1.1The DES Selection Function
Page 60: and the 32-bit block input isY ¼ y
Page 64: communication package placed in orb
Page 68: 2Satellites2.1 OVERVIEWA satellite
Page 72: stable over their operating tempera
Page 76: FIGURE 2.3 Geometric properties of
Page 80: at the altitudes of satellites, the
Page 84: whereg ¼ acceleration due to gravi
Page 88: 2.3 COVERAGE AREA AND SATELLITENETW
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The apex angle required at the sate
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the frontline satellites is then pa
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station antenna must be pointed to
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and the azimuth angle is a z ¼ 180
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2.5.3 Swath WidthThe width of the v
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2.6.3 System Speci¢cations: Analys
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Like all materials that require cou
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By the first definition, the system
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SolutionFrom (2.28), we can estimat
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FIGURE 2.11An example of redundancy
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adiators. An antenna array is a fam
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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,
Page 360:
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
Page 528:
Frequency divisionmultiple accessFr
Page 532:
MultiplexingNetworkOmnidirectionala
Page 536:
UplinkUser-to-networkinterfaceThe e
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