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IEEE Antennos and Propagation Society Newsletter, February 1985

Allen GlissonDepartment of ElectricalEngineeringUniversityof MississippiUniversity,M S 38677(Sal)232-5353

BOOK BEvIgwS

Communication Sa te ll it es n heG e o s t a t i o n a r y O r b i t ,by Donald M. Jansky and Michel C. Jeruchim,ArtechHouse, Dedham, MA 1983, x i i + 519 pages, ISBN: 0-89006-115-7, h ar dc ov er , $60.00.

The frequencypectrum and geos tati ona ryrb i t(GSO) a re in it en a t u r a l e s o u r c e s and t h e i r e f f i c i e n tu se eq u i r e s h eco o r d in a t io nofb o thpol ic y and tech-n o lo g ica lac to r s . This book i s ap p a r en t ly h e i r s tto onso l ida te and pres en t he x tensivem a te r i a l ont h i ssu b jec t h a th e r e to f o r ehas been sca t te red n hel i t e r a tu r e . The au th o rs 'n tendedudienceonsis tsof ...pra ctici ng pect rum managers i n government andindust ry ,o l icylann inger so nn el , and communica-tio ns ngin eers and systemesigners...". Thempha-s i s i s on systems na lysis a ther handesign and im-plementation echniques.

The GSO i s theuniqueorbithav ing an a l t i t ud eo f36.000 km and a periodo f one s id e r e a l d ay ; sa t e l l i t e si n this o r b i t appea r tati ona ry when viewed from theea r th . The o r b i t l sp ec t r u m t i l i z a t i o nf f i c i e n c y i su s u a l l y measured as th enformationandwidthe.g.number ofv o ice h an n e l so rb i t a t e )p e r MHz of RFbandwidthpe rdegree of o r b i t a l a r c , where th e o r b i t a lgreeslonghe ava ila ble 360 degrees fongitude.spacing between s a t e l l i t e s , A O, i s expressed in de-Sourcesfnterfer ence among se pa ra tea t e l l i t esystemsncludeheidelobeesponsesfheer-r e s t r i a ln t e n n a s ,he co- and cros s-pol arize de-s p o n s e so f e r r e s t r i a l and sa t e l l i t ean t en n a s and th ep a t t e r n o l lo f f and s id e lob e e sp o n ses fhe a te l -l i t e an tenna beams. Ind d i t i o n ,r o ss - p o la r i za t io nin t e r f e r en ce an lim it the apaci tyof a dualpolar-izedrequencyeusein k . Among the many o therf a c t o r sha t must beonsideredo maximize or bi t/ -spec t rum ff ic iencyre: andw idth-ef f icient modula-tion and accessmethods, requencyplann ing ,sa te l l i testa tion kee ping . and beam poi ntin g.

The authorsp o in to u t h a t h e GSO i s "crowded" i nterms fpectrum and orb ita l pac e and w i l l becomemore so i n t h euture.here ma y be skep t ics whowould no te heapparen t ronyof h isc la im nv iewofth e ac t h a t h eb o o k ' sp u b l i ca t io nco in c id eswi th acur ren tt ransponder lu t" : A December, 1983 su rv eyof 14 U.S. d o m es t i c sa t e l l i t e sn d i c a t e d that 143transpondersoutof a to ta l o f 312 in o r b i t were id l e- a cap ac i ty t i l i z a t io n f n ly 5 4% (The New YorkTimes,April0.984 ). By Augu st, 1984 th e C-Band

transponderurp lus was beingedu ced s l i g h t ly , u teven so , the re were 145 inacti ver an sp o n d e r s u t o f360 , a u t i l iza t ion o fon ly 60% (S at e ll i t e Week, August6, 984).The INTELSAT space segment i s a l sou n d e r - u t i l i z eda t t h e moment due toslu ggi sh demand growth f or nt er -n a t i o n a lir c ui ts . And to make mat tersorse,hefu ture g rowtho f s a t e l l i t e s ys te ms i s b e in g e r io u s lychallenged by the dventofhigh-capacity iber-opticc a b l e s , a t l e a s t o rp o in t - to - p o in t p p l i ca t io n s . In-deed,he TAT-8 tr an sa tl an ti cib e ra b l ech ed u ledf o rp e r a t io nn 1988 wi thapaci tyqu iva len tf37,800 oicehannels romiseso e a serious com-pe ti to r o h e INTELSAT V I s a t e l l i t e s , e ac h f whichhas a capacityofabo ut 33.000 voi cechannels . An ar-t i c l e in th e May 21, 1984 is su eo f BUSINESS WEEK sug-g e s t s h a t 'I.. . f i b e r o p t i c s i s even li ke ly o makeob-so le t e h e l e e t sof communications s a te l l i t e s now re-l ay in gata aroundheworld.hi sechnology w i l lmake ground ommun ications so cheap and fas t ha t few

commercialommunication satell i tes w i l l be launchedin th e1990's."Maybe. But th eprophetsof doom ove rlo ok he pos-s i b i l i t y t h a t s uc hcompetit ionmightstimulate urthersa t e l l i t e gr owth and in n o v at io noro tho in t - to -po in tswel l as wideband multidestination p p l i ca -t ions uch shin -rou te and bro adc ast ing . The Timesa r t i c l eu g g e s t e dh a ta te l l i te apa c i ty demand i sc y c l i c . This i s presumptuous s inceh en t i r en -d u s t r y sn ' tol d enough tohaveexperienced any sig ni-

f i c an tcy lce sy e t !The po in t fh i s i g r e s s i o n i s t of f i r mh a tth is book i s indeedimely. The con tin ued iab il i tyand com pet it i ven ess f ate ll i te communications w i l l

ultimately depend on i t s co s t f f ec t iv en ess and th a t ,i nh e long run, i s d i r e c t l y e l a t e d o r b i t a l andspect rum ef f ic iency .This book i s e r t a i n l y a c on v en ie n tourcefr e f e r en cem a te r i a l on pol icy and techn ica l ssues e-l a t ed o i t s in tended ub jec tof he GSO and i t s ef-f e c t i v et i l i z a t i o n . I t i s a p p a r e n t l yh ei r s tsy s t em a t i c r ea tm en to fa l l e l ev an ta sp ec t so f n t e r -ference nlysis ncluding hemajor ntenna ontr ibu-t io n s swe l l sh e f f ec t s f requenc y lans and

analog and digitalm o d u la t io n s . I t beginsith anoverviewfolicyevelopments and in t ern a t i ona lregu la t ions . Next i s presen tedhe ub jec tmat ter ft h ea r g es t a r t fhe book, namely th eechnica lanalysisof pectrum and or bi tu t i l i z a t io n . B eg in n in gwithheimpl e homogeneous model, which po st ul at esid en t i ca ly s t em squid ista nt from eachtherlongth e r c , h e n f lu en ceo f n t en n a id e lo b e n v e lo p es ,f requency n ter leav ing ,modula t ionparameters , a te l -l i t e p ac i n g , and p o la r i za t io n r ed i sp l ay ed . I t thenproceedsn toeeperevelsfe ta i lover inghemore realist icb u tco mp li ca te d non-homogeneous ca se , adeta i led rea tmen t f na log and d ig i ta lm o d u la t io n sfrom the iewpoin t f pectrum fficiency, a disc us-s io no f h ean a ly t i ca la sp ec t so f n t e r f e r en cecan ce l -la ti o n and reduc tion echn iques , and a number of ap-pendicesdealingwithmodulationparameters, GSO geo-metry, tationkeeping, and other opics .

Whi le the vera l l u t l in e i s l o g ica l ly r d e r ed ,the book suffers from severallawsncluding an un-usu all y arg e number of ypographical and spe ll i ng e r -rors , giving heappearance that i t was edited h a s t i l y23

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IEEE Antennas and Propagation Society Newslelter, February 1985andushednto r int . Also, theechnical resenta-t i o n s r e o t f o n s i s t en t u a l i t y . The a r i t h m e t i co f n t e r f e r en ceca lcu la t io n s i s g e n e r a l l y s t r a i g h t f o rward but ften ppe arso e more complicatedhannecessary ecause fhe need to eeprac k f manyin t er fe ren ce n t r ies and pa ths .This ookkeepingas kr e su l t snhe res enc e f many sub sc rip ts and thec l a r i t yo f h ep r e s e n t a t i o n so f t e n u f f e r s n h e at-tempt to be comp lete ly enera l and rigo rou s. In t h i sregard, he uthorsmighthave upplemented hederi-va t ionsith a few well-cho senpecif icxamples.Nev e r th e l e s s , h e e r s i s t en t e ad e r will gain an ap-pre cia tio n f how themulti tude fndividual ara-metersn a s a t e l l i t e communicat ionsy s t em in t e r ac tto lim'it the vera l l apac i ty . While th i s a th er ex-pensive book i s n o t i k e ly o in dwidespread accep-tance among subsystem and component designers, i tshould be a convenient eference or ystemdesignersand planners.

lhe book i s d iv id ed n toPa r t s I , 11, and I11 p lu sappendices .ar t I i s wr i t t en by th ei r s tu t h o r(Jansky) and parts I1 and I11 by Jeruchim.he astm a jo r i tyo fm a te r i a l i s in t h e s e a t t e r two P a r t s .

P a r t I , Regulatory and PolicyConsiderations, de-s c r i b e sh e GSO g eo m e t r i ca lea tu r e s ,r e sen t shee v o l u t i o no fs a t e l l i t epo li cy from theea r lyy ea r s o1982, and l i s t s t he r om inent sa t e l l i t e e r v i ce s andfrequencybands.This hortbut eadable ection m o -t i v a t e sap p r ec i a t io n o r h e many p o l i t i c a l a s we l l a st ech n ica lac to r sf f ec t in gn te r n a t io n a lg r eem en t sf o r a t e l l i t e use. Here ared isp layed requency l lo -ca t ion har ts and frequency har ing and coord ina t ionc r i t e r i a s u c h a sh e CCIR Recommendation 4 6 6 ; i .e . .the "ATIT rule." Ibis r u l ea l l so ro o r d i n a t i o namong administrations when intersystemn te r f e r en cepower increases a l i n k ' s q u iv a l en tn o i se em p er a tu r eby 4% or more.

Chapter 3 gives a chronology of policy evelop-m en t s ,s t a r t i n gwi th n t e r n a t io n a lagreeme nts and cu l -minatingwithhe U.S . pol icy l lowinghe x is tenceu f many owners and operatorso fd o m es t i c a t e l l i t e s .While this chapter i s asimely as can be expected,g iv en h ep u b l i ca t io nd a te , h epoli cy and regula torya r e a sa r ec u r r e n t l yve ry dynamic and this i s t h es o r to fm a t e r i a l that i s threatenedwith bso lescence al-most as soon s i t i s published. For example, recentp e t i t i o n s fo r deregula t ion in t h e n t e r n a tio n a l r en acouldnothavebeen reated in this book but may pro-f o u n d l ya l t e r u t u r ed i r e c t i o n s in satell i te communi-ca t io n s .

P a r t 11, Technica lConsiderations, eginswi th ad esc r ip t io n fhe homogeneous model in Chapter 4.Here are ef ined hemea sur es f rbi t and spectrumu t i l i z a t i o n n te rm s o f :vo icechannels or b i t s / s e c / -MHz/degree-of-arc. Alternatively, given t h a t a l lo th e rp a r am e te r sa r e i x ed , h eu t i l i z a t io nca n be ex-The s t ra igh t fo rward pp l ica t io n f he ink quat ionpressedshe m i n i m u m i n t e r s a t e l l i t ep a c i n g , Ae.l e ad so an e x p l i c i t f o r m u l aorarr ier- to-inter-f e r en cea t ioC/I ) and s ignal - to - no iseatio (SIN)for any system in the resence fhe thers . Thisan al ys is shows theerymportantnfluencefheear th n tenna ide lobe nvelopes on A B . Antenna de-s ig n e r sa r ewel l aware o f h i s as theyattem pt o de-vel op nte nna s whose gain nvelop e beyond one degr eefrom boresight i s l e s sha n 29-251agB wh ile nti cip at -ing even more str i ngen t utur e equ irem ents that mayportend he demise of he us e of ymmetrical ef lec-t o r s . Dual p o l a r i z a t i o n is discussed ere s i s thee f f e c t on cap ac i ty fmodulationype and frequencyin t e r l eav in g .m e ead e r n t e r e s t ed in a cursory un-ders tand ing of theseac to r s o u ldu f f i cewi thhem a te r i a l in t h i sch ap te r .

For thoseeq u i r in gr ea t e re t a i l ,h ap te r 5tr ea ts he more re a li s t ic nom-homogeneous casewheresymmetry i s l o s tei th er because ach ystem has d i f -f e r en t a r am e te r s or becausefropagationondi-tions, assumed tobe bs en t n he homogeneous case .homogeneous carr iers, leadingohe d e f i n i t i o n s o rThe analysisroceeds by considering p a i r s o f non-"is ola tio n" between networks. lh ise a d so a de-s c r i p t i o no f n t e r f e r e n c ec r i t e r i a o r a s i n g l ee n t r yand f o r h e o t a l n t e r f e r en ce . n t e r n a t io n a l eg u la -t i o nl a c e s limits on both. therop icsn thisc h a p t e r n c l u d es a t e l l i t ec lu s te r in g and f requency re-use a t t h e a t e l l i t ev i am ul ti pl e beams. Once again,givenhe se fhe most e f f ic ien t reque ncy lansand m o d u la t io n s , h e a t e l l i t ean ten n ap r o p e r t i e sa r ea s ig n i f i can t a c to r im i t in gu l t i m a t ec a p a c i t y .

P a r t 111, I n t e r f e r en ce , o v e r s in g r e a t e r e t a i lt h e u b jec to f n t e r f e r en ce as ca lcu la t ed or measureda t the eceiver .Chapter 6 d ea l swi th n a lo g ig n a l sand concentrates on FDMIFM telephony and TV. The pri-mary measureof nterference i s th enoise power ra ti o(NPR) and exp re ss io ns redeveloped or he NPR fo r anumber o fm u l t i p l e a r r i e r s o rb o th n t e r l e av ed andnon-interleaved cases .Chapter 7 describeshenterference erformance

o fd i g i t a lsi gn al s. Of course, heprimarymeasureofperformance i s t h e b i t e r r o r r a t e (BER) b u t , as point-ed ou t , he acko f a l i n ea r e l a t io n sh ip b etween h ewaveforms nd the BER makes exacta n a l y s e sd i f f i c u l t .Eowever, approximateormulas and BFX bounds are de-terminedor a number ofn t e r f e r en cecen a r io so rthepeci f icig i ta lmodula t ionsfoheren thases h i f t keying (CPSK) and m i n i m u m sh i f t k ey in g ( M S K ) .One observation made in the hapter i s t h a tco n s id e r -inghe nterference oise o eGaussian rovides aconvenientupp er bound on BBR f o r C j N ' s of genera l n -t e r e s t . '&is al so seems too ldorheonl inearchannelwith hardwired synchronization, butwi thsynchrecovery heGaussianapproximationdoesnot bound theperformance.

F in a l ly .ch ap te r 8 d e a l swi th n ter f eren ce reduc-t i on and cancel la t ionechniques . I t d esc r ib e sh euseof an auxilia ry ntenna oprov ide a su b t r ac t io no r can ce l l a t io n signal when a s in g le n t e r f e r in g p a t h ,such as a s ig n a l en te r in g via a sidelobe,ca nbe den-t i f i ed . B o th RF and I F can ce l l a t io n r ed esc r ib ed asare basebandechniquesornalogmodulation. Ther em a in d e r o f h e chap te r b r i e f ly o u t l i n e s h e co n cept sof beam shaping and adapti ve nulling with antenn a pat-t e r n s as well as p o la r i za t io nn u l l in g ech n iq u es .

The Appendices over a v a r i e t yo f o p i c s in somed e t a i l .B e s e p p e n d i c e s are g en e r a l lye ryo o r lywr i t ten and appearo aveo ta l ly scaped d i t ing .Appendix A. "Some Sign al-to -Noi se elati onshi psorAnalog Sign als," ontai ns so many e rr o rs and typos sto be almostunreadable.

i n t e n t o f i t s au thors . It will be a u se f u lso u r ceo fIn conclusion , th is book g en e r a l ly a t i s f i e s h er e f e r en cem a te r i a l on th e u b jec to for bi t and spec-trum u t i l i z a t i o n tha t may appealo ystem lanners.It w i l l b e e s su se f u l oen g in ee r sco n ce r n edwi th im -p lem en ta t io n o f sp ec i f i c h ar dwaredesigns.

Reviewed byDaniel F. DiFonzoCommunications S at el l i te Cow.95 0 L'EnfantPlaza, S.W.Washington, DC 20024

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