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CryptographyCryptographic keymanagementDecodingDecryptionDemodulationDelayDownlinkDragEarth stationEncryption(enciphering)FeedFootprintForward errorcorrectionA science that comprises encryption, decryption, anda cryptographic key management unit.The generation, distribution, recognition, and receptionof the cryptographic keys (passwords).The process required to reconstruct the data bitsequence encoded onto the carrier.The unlocking of the locked (decrypted) message; thereverse of encryption.A process by which the original signal is recoveredfrom a modulated carrier; the reverse of modulation.Time a signal takes to go from the sending stationthrough the satellite to the receiving station.The space-to-earth telecommunication pathway.The friction between a moving vehicle through theearth’s atmosphere opposing the vehicle’s forwardmotion.A terrestrial terminal that provides a means of transmittingthe modulated RF carrier to the satellite withinthe uplink frequency spectrum and receiving the RFcarrier from the satellite with the downlink frequencyspectrum. It is the vital link between satellite andcommunications users.The process of converting messages, information, ordata into a form unreadable by anyone except theintended recipient.The radiofrequency (RF) input=output device.An area on earth illuminated by a satellite antenna. Itsshape and size depend on a number of factors,including the antenna design and the satellite’s angleof elevation.A transmission error detection and correction techniquethat, in addition to detecting errors, also correctserrors at the receive end of the link.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
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interpreting or uncovering the deci
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cryptographic keys K ti (where i ¼
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FIGURE 1.6Block ciphering technique
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FIGURE 1.7Part of block ciphering w
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Based on the ordering sequence of (
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TABLE 1.1 (continued )S612 1 10 15
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For an uncoded message x and the fe
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2. Your task is to develop a commun
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FIGURE 2.1Geometry of a satellite.
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Future trends in satellite antennas
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In the United States, the three sat
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TABLE 2.3Typical Links Frequency Ba
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FIGURE 2.4Satellite period and orbi
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FIGURE 2.6An illustration of covera
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FIGURE 2.7constellation.A sketch of
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width of 1:73 with reduced coverag
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y ¼ elevation angle of satellite f
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We can conclude that the antenna mu
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FIGURE 2.9Design flowchart of a sat
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Risk control and monitoring measure
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TABLE 2.4Antenna Selection Criteria
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Then the system availability can be
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In fact, MTBF is the reciprocal of
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2.7 ANTENNASBased on function, sate
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Two kinds of horns in common use ar
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FIGURE 2.13Geometry of a parabolic
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FIGURE 2.14 Axisymmetric reflector
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A transceiver antenna is a single a
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The gain, in the axial mode, of a h
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angles, spacecraft may shadow the s
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3. The probability of both parallel
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the baseband signal (more details a
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matrix in the communications subsys
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FIGURE 2.24Typical transfer charact
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4. Iridium LCC (1997). Iridium Syst
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3Earth StationsIn Chap. 2 we discus
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The most popular forms of modulatio
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Small earth stations are antennas w
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FIGURE 3.2BPSK space diagram.Instea
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OQPSKOffset QPSK (OQPSK) is a modif
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FIGURE 3.7An 8-PSK space diagram.an
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aud. The word ‘‘baud’’ hono
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Noise power density N 0bandwidth:N
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We observe in (3.11) that E b =N 0
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to (3.23) shows that a margin of 11
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FIGURE 3.12 Principle of scrambling
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Equalization FilterAn equalization
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that is, N zeros at the top and bot
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Example 3.2: Consider a transmissio
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which can be written as89>=R xy ðt
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ecause a voice signal is usually hi
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systems is discussed in Sec. 4.2. O
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where T e is the equivalent tempera
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operating principle of all directio
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performance of the satellite commun
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3. For two independent sources, wit
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FIGURE 3.21 A representation of mut
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In practice, Eqs. (3.78) and (3.76)
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This condition is always satisfied
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Copyright © 2002 by Marcel Dekker,
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epeaters overshooting into subseque
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6. Conventional BPSK modulation all
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4Satellite LinksA satellite link co
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FIGURE 4.2 Basic antenna parameters
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For unity efficiency, and substitut
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This expression neglects losses oth
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This expression is equally valid fo
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and Lin [5]:whereL ¼L o1 þ L oðr
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3. Calculate attenuation A r in dB
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4.2.1 Intersatellite LinksAs indica
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We know from (4.4b) that f c is dep
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FIGURE 4.9 Cross-link transmission
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Follow the uplink procedure for the
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Satellite:Frequencies:14.75 GHz up
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6. For link to be maintained betwee
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5.1 PRINCIPLES OF MULTIPLE ACCESSAs
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neously, their transmissions collid
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technique and would remain the most
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FIGURE 5.4 Typical TDMA frame struc
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FIGURE 5.6TDMA throughput for an IN
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and transmits through the satellite
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FIGURE 5.8FDMA total capacity respo
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tion; that is, log e ð1 þ xÞ x t
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REFERENCES1. Spilker, J.J. (1977).
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6.1 CHANNEL CODINGNoise within a tr
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where G is a generator matrix that
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The syndrome is a single word of le
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SolutionComparing (i) and (ii) with
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Cyclic CodesCyclic codes are a subs
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When errors occur in bursts, the nu
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FIGURE 6.3Rate 1/2 convolutional en
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us to a particular node in the tree
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FIGURE 6.6 Trellis diagram of Fig.
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FIGURE 6.9 Trellis diagram of Fig.
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A generalized Viterbi algorithm is
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3. Huffman, D.A. (1952). A method f
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4. Draw a block diagram for a convo
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1. The first essential requirement
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use. The ITU Radio Regulations gove
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Within the CCITT structure exist a
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7.2 NATIONAL AND REGIONAL REGULATIO
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8Mobile Satellite System Services8.
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Copyright © 2002 by Marcel Dekker,
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may reside within a single LDSN. Th
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destination through the intermediat
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can be used at separate user-to-net
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where0 n 40 m 246n þ m 24ð8:
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elationship between OSI and ISDN: t
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network and for networks to communi
Page 474: Copyright © 2002 by Marcel Dekker,
Page 478: shown in Fig. 8.1. Some of the attr
Page 482: It is possible to formulate a metho
Page 486: transmitting power. The smaller the
Page 490: FIGURE 8.12Tessellated clusters of
Page 494: 8.3.1 The InternetThe Internet cons
Page 498: SecurityData security is a matter o
Page 502: Copyright © 2002 by Marcel Dekker,
Page 506: well suited to this method. The con
Page 510: 4. Describe the protocol used on th
Page 514: B Aperture length in E-plane of a p
Page 518: e lf cf lghh 0kk ek slmm km snn cn
Page 522: Appendix BGlossary of TermsAntennaA
Page 528: Frequency divisionmultiple accessFr
Page 532: MultiplexingNetworkOmnidirectionala
Page 536: UplinkUser-to-networkinterfaceThe e
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