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6. Conventional BPSK modulation allows the transmission of either 0 or180 phase values. If the phases in the signal are 60 or 120 ,willtheresulting waveform still remain BPSK?7. If data are scrambled in a transmitter, a corresponding descrambler will berequired in the receiver. Explain how the data can be recovered. Alsoexplain modes of transmission where a descrambler (a) must be synchronizedto the incoming data and (b) operates without initialization. Whattype of error, if any, will be introduced in (b)?8. Consider a channel for which the following sample values of its pulseresponse are given:z c ð0Þ ¼1:0; z c ðTÞ ¼0:2; z c ð2TÞ ¼ 0:08; z c ð3TÞ ¼0:008z c ð 3TÞ ¼0:001; z c ð 2TÞ ¼ 0:05; z c ð TÞ ¼0:12Find (a) the taps coefficient for the 3-tap zero forcing equalizer and (b) theoutput samples for mT ¼ 2T; T; 0; T, and 2T.9. A 20-m Cassegrain antenna, whose receive antenna gain is 54.53 dB at11.2 GHz and ambient temperature is 275 K, is characterized by thefollowing parameters:Antenna noise temperature ¼ 60 K.Waveguide loss ¼ 0.3 dB.The LNA has a 20-dB gain and an effective noise temperature of350 K.If the effective noise temperature of the downconverter is 1500 K,estimate the earth station system noise temperature and the antennagain referred to the input of the LNA.10. A satellite repeater system consists of three channels: the uplink, transponderprocessing unit, and the downlink. The uplink has an errorprobability of 0.1%. The processing unit has an error probability of0.025%. If the downlink error probability of 1% is desired, calculate(a) The capacity of each channel(b) The conditional probability of the whole system(c) The expected capacity of the overall system11. Write a computer program to design an equalizer for specified channelconditions using (a) zero forcing and (b) minimum mean-square errorcriteria.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
Page 230: Example 3.2: Consider a transmissio
Page 234: which can be written as89>=R xy ðt
Page 238: ecause a voice signal is usually hi
Page 242: systems is discussed in Sec. 4.2. O
Page 246: where T e is the equivalent tempera
Page 250: operating principle of all directio
Page 254: performance of the satellite commun
Page 258: 3. For two independent sources, wit
Page 262: FIGURE 3.21 A representation of mut
Page 266: In practice, Eqs. (3.78) and (3.76)
Page 270: This condition is always satisfied
Page 274: Copyright © 2002 by Marcel Dekker,
Page 278: epeaters overshooting into subseque
Page 284: 142. Simulate the probability of bi
Page 288: FIGURE 4.1A simplex link.baseband c
Page 292: Chapter 2, Sec. 2.7, discusses that
Page 296: From (4.6), the received power P r
Page 300: FIGURE 4.3A model of the combined-l
Page 304: 4.1.2 Rain AttenuationRain attenuat
Page 308: FIGURE 4.5rates.Average rainstorm p
Page 312: FIGURE 4.6Adjacent satellite interf
Page 316: FIGURE 4.8Satellite separation dist
Page 320: inability of satellite A to accurat
Page 324: FIGURE 4.10 Cross-link E b =N 0 vs.
Page 328: 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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