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H1-channels are designed to carry very high-speed facsimile signals,standard compressed videoconferencing signals with reduced spatialresolution and movement, and transmission capacity for privatenetwork trunks.H2-channels are intended to satisfy the requirements of fast-scancompressed video sources.The H4-channel is designed for a variety of user-information functions,including enhanced video, compressed high-definition television(HDTV) and telecasting.For circuit-switched connections none of the H-channels carries signallinginformation.Channel Structures. Channel structures define the maximum digitalcarrying capacity in terms of bit rates across the ISDN interface. The bit ratesand channel combinations are chosen to match the aggregate data rates of theintended application(s). The fundamental objective of channel combinations isto create the possibility of several simultaneous and independent voice or datacalls, either by the same or by different terminals over a single user-to-networkinterface particularly for synchronous channel structures.The basic channel structure, corresponding to basic access, is comprisedof two B-channels and one D-channel. As an illustration, for an aggregate datarate of 144 kbit=sec, we can choose2B þ 1D ¼ð2 64 þ 16Þ kbit=secð8:1ÞThe primary channel structure corresponds to primary access, designed toaccommodate applications requiring more than two simultaneous connectionsand=or data rates in excess of 64 kbit=sec. For example, for an aggregate datarate of 1.544 Mbit=sec, we choose eithernH0 þ mB þ Dð8:2aÞwhere the integers n and m have values in the range0 n 30 m 236n þ m 23ð8:2bÞor in the formnH0 þ mBð8:3aÞCopyright © 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.
Page 410: FIGURE 6.9 Trellis diagram of Fig.
Page 414: A generalized Viterbi algorithm is
Page 418: 3. Huffman, D.A. (1952). A method f
Page 422: 4. Draw a block diagram for a convo
Page 426: 1. The first essential requirement
Page 430: use. The ITU Radio Regulations gove
Page 434: Within the CCITT structure exist a
Page 438: 7.2 NATIONAL AND REGIONAL REGULATIO
Page 442: 8Mobile Satellite System Services8.
Page 446: Copyright © 2002 by Marcel Dekker,
Page 450: may reside within a single LDSN. Th
Page 454: destination through the intermediat
Page 458: can be used at separate user-to-net
Page 464: information. The transfer cell prov
Page 468: The OSI layers are divided into two
Page 472: plane is denoted by U, the control
Page 476: interfacing, maintenance, and conne
Page 480: adjoining base station to scan the
Page 484: FIGURE 8.9Geometry of a polygon.The
Page 488: FIGURE 8.11Splitting cells into sma
Page 492: causes signal fading. Of course, th
Page 496: FIGURE 8.14TCP=IP suite and its rel
Page 500: access to an Internet point of pres
Page 504: message security via satellite is d
Page 508: 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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