Annex 10, page 1 of 19. Annex 10. Determination of the basic transmission loss in the Fixed Service. Annex 10, page 1

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1 Annex 10, page 1 of 19 Annex 10 Determnaton of the basc transmsson loss n the Fxe Servce Annex 10, page 1

2 Annex 10, page of 19 PREDICTION PROCEDURE FOR THE EVALUATION OF BASIC TRANSMISSION LOSS 1 Introucton The precton proceure prove n ths chapter s base on the Recommenaton ITU-R P The proceure s approprate to rao relay lnks operatng n the frequency range of about 0.7 GHz to 50 GHz. The metho nclues a complementary set of propagaton moels, whch ensure that the prectons embrace all the sgnfcant propagaton mechansms relevant to long-term nterference. Methos for analysng the rao-meteorologcal an topographcal features of the path are prove so that prectons can be prepare for any practcal nterference path fallng wthn the scope of the proceure. The precton s acheve n four steps escrbe n the sectons, 4, 5 an 6. Bases for the moels use n the precton It s assume that nterference, whch s sgnfcant urng a small percentage of tme (shortterm) can not eterorate the performance an the ablty of the transmsson. As a result of that assumpton, only long-term nterference s taken nto account, an therefore the tme percentage, for whch the calculate basc transmsson loss s not exceee, s taken as 0%. Accorngly, the proceure uses four propagaton moels lste below: lne-of-sght (nclung sgnal enhancements ue to multpath an focusng effects); ffracton (embracng smooth-earth, rregular terran an sub-path cases); tropospherc scatter; surface uctng an layer reflecton. Depenng on the type of path, as etermne by a path profle analyss, one or more of these moels are exercse n orer to prove the requre precton of basc transmsson loss. The propagaton precton moels prect the average annual strbuton of basc transmsson loss. As the rao-meteorologcal an topographcal features for the terran of all sgnatory s countres appeare to be almost the same, the common values were aopte. The values for such parameters are as follows: N : the average rao-refractve nex lapse-rate through the lowest 1 km of the atmosphere, (N-unts/km) = 45 N0: the sea-level surface refractvty, (N-unts)= 5 p : Pressure = 101 hpa t : temperature = 15 C Annex 10, page

3 Annex 10, page of 19 Step 1 of the precton proceure: Preparaton of the nput ata The basc nput ata requre for the proceure s gven n Table1. All other nformaton requre s erve from these basc ata urng the executon of the proceure. TABLE 1 Basc nput ata Parameter Preferre resoluton Descrpton f Frequency (GHz) t, r 1 Lattue of staton (secons) p 1 Requre tme percentage(s) for whch the calculate basc transmsson loss s not exceee t, r 1 Longtue of staton (secons) htg, hrg 1 Antenna centre heght above groun level (m) hts, hrs 1 Antenna centre heght above mean sea level (m) Gt, Gr 0.1 Antenna gan n the recton of the horzon along the great-crcle nterference path (B) NOTE 1 For the nterferng an nterfere-wth statons: t: nterferer r: nterfere-wth staton 4 Step of the precton proceure: Raometeorologcal ata The values of rao-meteorologcal parameters, whch coul be etermne as common to all countres of West, South an Central Europe are gven n. In the precton proceure the tme percentage for whch refractve nex lapse-rates exceeng 100 N-unts/km can be expecte n the frst 100 m of the lower atmosphere, 0 (%) must be evaluate. Ths parameter s use to estmate the relatve ncence of fully evelope anomalous propagaton at the lattue uner conseraton. The value of 0 to be use s that approprate to the path centre lattue. Pont ncence of anomalous propagaton, 0 (%), for the path centre locaton s etermne usng: μ μ % for 70 () β (1.) 4.17μ1 μ4 % for 70 where : path centre lattue (egrees) whch s not greater than 70 an not less than -70 Annex 10, page

4 Annex 10, page 4 of 19 The parameter 1 epens on the egree to whch the path s over lan (nlan an/or coastal) an water, an s gven by: 1 tm (.) where the value of 1 shall be lmte to 1 1, wth: 1 e lm (.) where tm : lm : longest contnuous lan (nlan + coastal) secton of the great-crcle path (km) longest contnuous nlan secton of the great-crcle path (km) The raoclmatc zones to be use for the ervaton of tm an lm are efne n Table. ( )logμ1 10 for 70 μ4 (4.) 0.logμ 10 1 for 70 TABLE Rao-clmatc zones Zone type Coe Defnton Coastal lan A1 Coastal lan an shore areas,.e. lan ajacent to the sea up to an alttue of 100 m relatve to mean sea or water level, but lmte to a stance of 50 km from the nearest sea area. Where precse 100 m ata s not avalable an approxmate value may be use Inlan A All lan, other than coastal an shore areas efne as coastal lan above Sea B Seas, oceans an other large boes of water (.e. coverng a crcle of at least 100 km n ameter) Large boes of nlan water A large boy of nlan water, to be consere as lyng n Zone B, s efne as one havng an area of at least km, but exclung the area of rvers. Islans wthn such boes of water are to be nclue as water wthn the calculaton of ths area f they have elevatons lower than 100 m above the mean water level for more than 90% of ther area. Islans that o not meet these crtera shoul be classfe as lan for the purposes of the water area calculaton. Large nlan lake or wet-lan areas Large nlan areas of greater than km, whch contan many small lakes or a rver network shoul be eclare as coastal Zone A1 by amnstratons f the area comprses more than 50% water, an more than 90% of the lan s less than 100 m above the mean water level. Clmatc regons pertanng to Zone A1, large nlan boes of water an large nlan lake an Annex 10, page 4

5 Annex 10, page 5 of 19 wetlan regons, are ffcult to etermne unambguously. Therefore amnstratons are requeste to regster wth the TWG HCM those regons wthn ther terrtoral bounares that they wsh entfe as belongng to one of these categores. In the absence of regstere nformaton to the contrary, all lan areas wll be consere to pertan to clmate Zone A. Effectve Earth s raus The mean effectve Earth raus factor k50 for the path s etermne usng: 157 k50 (5.) 157± N Assumng a true Earth raus of 6 71 km an the average rao-refractve nex N (Nunts/km) for West, South an Central Europe of 45, the mean value of effectve Earth raus ae [km] can be etermne from: a e = 671 k 50 (6.) The effectve Earth raus [km] exceee for 0% tme, a, s gven by: a = 6 71 k (7.) where k =.0 s an estmate of the effectve Earth raus factor exceee for 0 % tme. 5 Step of the precton proceure: Path profle analyss Values for a number of path-relate parameters necessary for the calculatons, as ncate n Tables an 4, must be erve va an ntal analyss of the path profle base on the value of ae gven by equaton (6.). For path profle analyss, a path profle of terran heghts above mean sea level s requre. Havng thus analyse the profle, the path wll also have been classfe nto transhorzontal or lne of sght. Annex 10, page 5

6 Annex 10, page 6 of 19 TABLE Parameter values to be erve from the path profle analyss Parameter lt, lr t, r hts, hrs b ct, cr Descrpton Great-crcle path stance (km) For a transhorzon path, stance from the transmt an receve antennas to ther respectve horzons (km). ). For a lne-of-sght path, each s set to the stance from the termnal to the profle pont entfe as the prncpal ege n the ffracton metho for 50% tme. For a transhorzon path, transmt an receve horzon elevaton angles respectvely (mra). For a lne-of-sght path, each s set to the elevaton angle of the other termnal. Path angular stance (mra) Antenna centre heght above mean sea level (m) Aggregate length of the path sectons over water (km) Fracton of the total path over water: = b / (8.) where s the great-crcle stance (km) For totally overlan paths = 0 Dstance over lan from the transmt an receve antennas to the coast along the great-crcle nterference path (km). Set to zero for a termnal on a shp or sea platform. Annex 10, page 6

7 Annex 10, page 7 of Constructon of path profle Base on the geographcal co-ornates of the nterferng (t, t) an nterfere-wth (r, r) statons, terran heghts (above mean sea level) along the great-crcle path shoul be erve from a topographcal atabase or from approprate large-scale contour maps. The preferre stance resoluton of the profle s that gvng an nteger number of steps of 0.1 km. The profle shoul nclue the groun heghts at the nterferng an nterfere-wth staton locatons as the start an en ponts. To the heghts along the path shoul be ae the necessary Earth s curvature, base on the value of ae foun n equaton (6.). For the purposes of ths Annex the pont of the path profle at the nterferer s consere as pont 0, an the pont at the nterfere-wth staton s consere as pont n. The path profle therefore conssts of n + 1 ponts. Fgure 1 gves an example of a path profle of terran heghts above mean sea level, showng the varous parameters relate to the actual terran. Table 4 efnes parameters use or erve urng the path profle analyss. The path length, (km), shoul be calculate accorng to the formula relate to the great crcle stance: =671 arccos(sn(φ t ) sn(φ r ) + cos(φ t ) cos(φ r ) cos(ψ t ψ r )) (9.) FIGURE 1 Example of a (trans-horzon) path profle th terran pont Interferng staton (T) t Mean sea level h l Interfere-wth staton (R) r h tg h h gt ts lt a e =k 50 a lr h gr h rg h rs Note 1 The value of t as rawn wll be negatve. Annex 10, page 7

8 Annex 10, page 8 of 19 TABLE 4 Path profle parameter efntons Parameter a e f λ h ts h rs θ t θ r Descrpton Effectve Earth s raus (km) Great-crcle path stance (km) Great-crcle stance of the -th terran pont from the nterferer (km) Incremental stance for regular path profle ata (km) Frequency (GHz) Wavelength (m) Interferer antenna heght (m) above mean sea level (amsl) Interfere-wth antenna heght (m) (amsl) For a transhorzon path, horzon elevaton angle above local horzontal (mra), measure from the nterferng antenna. For a lne-of-sght path ths shoul be the elevaton angle of the nterfere-wth antenna For a transhorzon path, horzon elevaton angle above local horzontal (mra), measure from the nterfere-wth antenna. For a lne-of-sght path ths shoul be the elevaton angle of the nterferng antenna 5. Path classfcaton The path must be classfe nto lne-of-sght or transhorzon. The path profle must be use to etermne whether the path s lne-of-sght or transhorzon base on the mean effectve Earth s raus of a e. A path s trans-horzon f the physcal horzon elevaton angle as seen by the nterferng antenna (relatve to the local horzontal) s greater than the angle (agan relatve to the nterferer s local horzontal) subtene by the nterfere-wth antenna. The test for the trans-horzon path conton s thus: (mra) (10.) max t max n max 1 ( ) (mra) (11.) 1 : h : hts : : elevaton angle to the th terran pont h hts 10 = - (mra) (1.) a heght of the th terran pont (m) amsl nterferer antenna heght (m) amsl stance from nterferer to the th terran element (km) e hrs hts 10 t = - (mra) (1.) a e hrs : nterfere-wth antenna heght (m) amsl : total great-crcle path stance (km) ae : mean effectve Earth s raus approprate to the path (equaton (6.)). Annex 10, page 8

9 Annex 10, page 9 of 19 Dervaton of parameters from the path profle for trans-horzon paths The parameters to be erve from the path profle are those contane n Table 4. Interferng antenna horzon elevaton angle, t The nterferng antenna s horzon elevaton angle s the maxmum antenna horzon elevaton angle when equaton (11.) s apple to the n 1 terran profle heghts. t max (mra) (14.) wth max as etermne n equaton (11.). Interferng antenna horzon stance, lt The horzon stance s the mnmum stance from the transmtter at whch the maxmum antenna horzon elevaton angle s calculate from equaton (11.). (km) for max( ) (15.) lt Interfere-wth antenna horzon elevaton angle, r The receve antenna horzon elevaton angle s the maxmum antenna horzon elevaton angle when equaton (11.) s apple to the n 1 terran profle heghts. n1 r max ( j ) (mra) (16.) j1 h j hrs 10 ( j ) j = - (mra) (17.) a j e Angular stance θ (mra) The angular stance θ s calculate usng formula : = 10 ae + t + r (mra) (18.) Interfere-wth antenna horzon stance, lr The horzon stance s the mnmum stance from the recever at whch the maxmum antenna horzon elevaton angle s calculate from equaton (11.). lr = - j (km) for max(θ j ) (19.) Annex 10, page 9

10 Annex 10, page 10 of 19 6 Step 4 of the precton proceure: Calculaton of propagaton prectons Basc transmsson loss, L b (B), not exceee for the requre annual percentage tme, p, s evaluate as escrbe n the followng sub-sectons. 6.1 Lne-of-sght propagaton (nclung short-term effects) The followng shoul be evaluate for both lne-of-sght an transhorzon paths. Basc transmsson loss ue to free-space propagaton an attenuaton by atmospherc gases: L bfsg = log f + 0 log + A g B (0.) Ag : total gaseous absorpton (B): ) ( B) A w( (1.) g o o, w() : specfc attenuaton ue to ry ar an water vapour, respectvely, an are foun from the equatons (.), (4.) : water vapour ensty: ρ = ω (g/m ) (.) : fracton of the total path over water. For ry ar, the attenuaton o (B/km) s gven by Recommenaton ITU-R P as follows: o f 7. r t rp 1.6 t r (54 f ) f rp 10 (.) f : frequency (GHz) rp = p / 101 rt = 88/(7 + t) p : pressure (hpa) - see t : temperature (C) see. ( r,,0.0717, 1.81,0.0156, 1 p rt ( r p, rt,0.5146, 4.668, 0.191, ( r p, rt,0.414, ,0.10, a ) ) ) ( rp, rt, a, b, c, ) rp rt exp[ c(1 rp) (1 rt )] For water vapour, the attenuaton w (B/km) s gven by: b Annex 10, page 10

11 Annex 10, page 11 of 19 w.981 exp[.(1 rt )] exp[0.7(1 rt )] g( f,) ( f.5) 9.41 ( f 18.1) exp[6.44(1 r )].661 exp[1.6(1 rt )] ( f 1.6) 6.9 ( f 5.15) 9. t exp[1.09(1 rt )] exp[1.46(1 rt )] ( f 80) ( f 448) exp[0.17(1 rt )] 901 exp[0.41(1 rt )] g( f,557) g( f,75) ( f 557) ( f 75) exp[0.99(1 r )] t g( f,1 780) f ( f 1 780) 1.5 rt (4.) r prt r prt rt g ( f, f ) 1 f f f f 4 Correctons for multpath an focusng effects at p an 0 percentage tmes: E sp =.6 [1 exp( 0.1 { lt + lr })] log (p/50) B (5.) E s =.6 [1 exp( 0.1 { lt + lr })] log ( 0 /50) B (6.) Basc transmsson loss not exceee for tme percentage, p%, ue to lne-of-sght propagaton: L b0p = L bfsg + E sp B (7.) Basc transmsson loss not exceee for tme percentage, 0 %, ue to lne-of-sght propagaton: L b0 = L bfsg + E s B (8.) 6. Dffracton The ffracton moel calculates the followng quanttes requre n 6.5: L p : ffracton loss not exceee for p% tme L b50 : mean basc transmsson loss assocate wth ffracton L b : basc transmsson loss assocate wth ffracton not exceee for p% tme. The ffracton loss s calculate for all paths usng a hybr metho base on the Deygout constructon an an emprcal correcton. Ths metho proves an estmate of ffracton loss for all types of paths, nclung over-sea or over-nlan or coastal lan, an rrespectve of whether the lan s smooth or rough. Ths metho shoul be use, even f the eges entfe by the Deygout constructon are ajacent profle ponts. Ths metho also makes extensve use of an approxmaton to the sngle knfe-ege ffracton loss as a functon of the mensonless parameter,, gven by: J ( ) 6.90log (9.) Annex 10, page 11

12 Annex 10, page 1 of 19 Note that J( 0.78) 0, an ths efnes the lower lmt at whch ths approxmaton shoul be use. J(ν) s set to zero for ν< Mean ffracton loss The mean ffracton loss, L 50 (B), s calculate usng the mean value of the effectve Earth raus, a e, gven by equaton (6.). Mean ffracton loss for the prncpal ege Calculate a correcton, m, for overall path slope gven by: h rs hts m cos tan 1 10 (0.) Fn the man (.e. prncpal) ege, an calculate ts ffracton parameter, m50, gven by: n1 10 m50 max mh 1, (1.) where the vertcal clearance, H, s: h h H h ts rs 10 (.) ae an h ts,rs : transmtter an recever heghts above sea level (m) (see Table.) : wavelength (m) = 0./f f : frequency (GHz) : path length (km) : stance of the -th profle pont from transmtter (km) (see 5.) h : heght of the -th profle pont above sea level (m) (see 5.). Set m50 to the nex of the profle pont wth the maxmum value, m50. Calculate the mean knfe-ege ffracton loss for the man ege, L m50, gven by: L m 50 J m50 f m otherwse (.) If L m50 = 0, the mean ffracton loss, L 50, an the ffracton loss not exceee for 0 % tme, L, are both zero an no further ffracton calculatons are necessary. Otherwse possble atonal losses ue to seconary eges on the transmtter an recever ses of the prncpal ege shoul be nvestgate, as follows. Mean ffracton loss for transmtter-se seconary ege If m50 = 1, there s no transmtter-se seconary ege, an the assocate ffracton loss, L t50, shoul be set to zero. Otherwse, the calculaton procees as follows. Calculate a correcton, t, for the slope of the path from the transmtter to the prncpal ege: 1 h cos tan 10 hts t (4.) m 50 Fn the transmtter-se seconary ege an calculate ts ffracton parameter, t50, gven by: Annex 10, page 1

13 Annex 10, page 1 of 19 t50 m50 1 max th 1 10 (5.) h 10 ts hm 50 H h (6.) ae m 50 Set t50 to the nex of the profle pont for the transmtter-se seconary ege (.e. the nex of the terran heght array element corresponng to the value ν t50 ). Calculate the mean knfe-ege ffracton loss for the transmtter-se seconary ege, L t50, gven by: L t50 Jt50 for t an (7.) 0 otherwse Mean ffracton loss for the recever-se seconary ege If m50 = n-1, there s no recever-se seconary ege, an the assocate ffracton loss, L r50, shoul be set to zero. Otherwse the calculaton procees as follows. Calculate a correcton, r, for the slope of the path from the prncpal ege to the recever: 1 hrs h cos tan 10 r (8.) m 50 Fn the recever-se seconary ege an calculate ts ffracton parameter, r50, gven by: n1 10 m r rh max (9.) 1 H h h 10 rs h (40.) ae m 50 Set r50 to the nex of the profle pont for the recever-se seconary ege (.e. the nex of the terran heght array element corresponng to the value ν r50 ). Calculate the mean knfe-ege ffracton loss for the recever-se seconary ege, L r50, gven by: Lr 50 Jr50 for r an n1 (41.) 0 otherwse Combnaton of the ege losses for mean Earth curvature Calculate the mean ffracton loss, L 50, gven by: L 50 m 1 e 6 L 50 Lm50 Lt 50 Lr for m otherwse (4.) In equaton (4.) L t50 wll be zero f the transmtter-se seconary ege oes not exst an, smlarly, L r50 wll be zero f the recever-se seconary ege oes not exst. If L 50 = 0, then the ffracton loss not exceee for 0 % tme wll also be zero. If the precton s requre only for p = 50%, no further ffracton calculatons wll be necessary (see 6..). Otherwse, the ffracton loss not exceee for 0 % tme must be calculate, as Annex 10, page 1

14 Annex 10, page 14 of 19 follows. 6.. The ffracton loss not exceee for 0 % of the tme The ffracton loss not exceee for 0 % tme s calculate usng the effectve Earth raus exceee for 0 % tme, a, gven by equaton (7.). For ths secon ffracton calculaton, the same eges as those foun for the mean case shoul be use for the Deygout constructon. The calculaton of ths ffracton loss then procees as follows. Prncpal ege ffracton loss not exceee for 0 % tme Fn the man (.e. prncpal) ege ffracton parameter, m, gven by: 10 m mhm (4.) m 50 m 50 H m h 10 h a ts h rs (44.) Calculate the knfe-ege ffracton loss for the man ege, L m, gven by: L m J m for m otherwse (45.) Transmtter-se seconary ege ffracton loss not exceee for 0 % tme If L t50 = 0, then L t wll be zero. Otherwse calculate the transmtter-se seconary ege ffracton parameter, t, gven by: 10 t tht (46.) t50 t50 H t h t50 10 t50 h a t50 ts t50 h t50 (47.) Calculate the knfe-ege ffracton loss for the transmtter-se seconary ege, L t, gven by: L t J t for t 0.78 (48.) 0 otherwse Recever-se seconary ege ffracton loss not exceee for 0 % tme If L r50 = 0, then L r wll be zero. Otherwse, calculate the recever-se seconary ege ffracton parameter, r, gven by: 10 r rhr (49.) r50 r50 Annex 10, page 14

15 Annex 10, page 15 of 19 H r h r50 10 h h r50 a r50 r50 rs (50.) Calculate the knfe-ege ffracton loss for the recever-se seconary ege, L r, gven by: L r J r for r 0.78 (51.) 0 otherwse Combnaton of the ege losses not exceee for 0 % tme Calculate the ffracton loss not exceee for 0 % of the tme, L, gven by: Lm L 1 e 6 Lm Lt Lr for m otherwse (5.) 6.. The ffracton loss not exceee for p% of the tme The applcaton of the two possble values of effectve Earth raus factor s controlle by an nterpolaton factor, F, base on a log-normal strbuton of ffracton loss over the range β 0 % < p < 50%. gven by: F = 0 p = 50% (5.) p I = 100 I for 50% > p > β 0 % (54.) = 1 for β 0 % p (55.) where I(x) s the nverse cumulatve normal functon. An approxmaton for I(x) whch may be use wth confence for x < 0.5 s gven n (59.). The ffracton loss, L p, not exceee for p% tme, s now gven by: L p = L 50 + F ( L L 50 ) B (56.) where L 50 an L are efne by equatons (4.) an (5.), respectvely, an F s efne by equatons (5. to 55.), epenng on the values of p an 0. The mean basc transmsson loss assocate wth ffracton, L b50, s gven by: L b50 = L bfsg + L 50 B (57.) where L bfsg s gven by equaton (0.). The basc transmsson loss assocate wth ffracton not exceee for p% tme s gven by: where L b0p s gven by equaton (7.). L b = L b0p + L p B (58.) The followng approxmaton to the nverse cumulatve normal strbuton functon s val for x 0.5 an s n error by a maxmum of It may be use wth confence for the nterpolaton functon n equaton (54.). If x < , whch mples 0 < %, x Annex 10, page 15

16 Annex 10, page 16 of 19 shoul be set to The functon I(x) s then gven by: I(x) = (x) T(x) (59.) x T( x) ln (60.) C T x C1 TxC0 D T ( x) D T ( x) D T ( x) 1 ( x)= (61.) 1 C0 = (6.) C1 = (6.) C = (64.) D1 = (65.) D = (66.) D = (67.) 6. Tropospherc scatter The basc transmsson loss ue to troposcatter, Lbs (p) (B) not exceee for any tme percentage, p, s gven by: Lbs 190 Lf 0log 0.57θ 0.15 N0 Lc Ag 10.1 log ( p/50) 0. 7 (68.) Lf : frequency epenent loss: L ƒ = 5logƒ-.5[log(ƒ/)] (B) (69.) Lc : aperture to meum couplng loss (B): 0.055( G r ) t G L c e (B) (70.) Ag: gaseous absorpton erve from equaton (1.) usng = g/m for the whole path length 6.4 Ductng/layer reflecton The precton of the basc transmsson loss, L ba (B) occurrng urng peros of anomalous propagaton (uctng an layer reflecton) s base on the followng functon: L ba = A f + A ( p) + A g B (71.) A f : total of fxe couplng losses (except for local clutter losses) between the antennas an the anomalous propagaton structure wthn the atmosphere: Annex 10, page 16

17 Annex 10, page 17 of 19 A f = log f + 0 log ( lt + lr ) + A st + A sr + A ct + A cr B (7.) A st, A sr : ste-shelng ffracton losses for the nterferng an nterfere-wth statons respectvely: 1/ 1/ 0log t, r f lt,lr 0.64 t, r f B for t, r 0 mra A st, sr (7.) 0 B for 0 mra t, r θ 0.1 mra (74.) t, r t,r lt,lr A ct, A cr : over-sea surface uct couplng correctons for the nterferng an nterfere-wth statons respectvely: 0.5 e ct,cr Act,cr 1 tanh (0.07(50 hts,rs )) B for 0.75 ct,cr lt,lr (75.) ct,cr 5 km A ct, cr 0 B for all other contons (76.) It s useful to note the lmte set of contons uner whch equaton (75.) s neee. A ( p) : tme percentage an angular-stance epenent losses wthn the anomalous propagaton mechansm: A ( p) = γ θ + A ( p) B (77.) γ : specfc attenuaton: γ = a e f 1/ B/mra (78.) θ : angular stance (correcte where approprate (va equaton (79.)) to allow for the applcaton of the ste shelng moel n equaton (7.)): 10 t r a e mra (79.) t, r θt,r 0.1lt,lr for θt,r 0.1lt,lr for θt,r 0.1lt,lr mra mra (80.) A( p) : tme percentage varablty (cumulatve strbuton): Γ p p A ( p) 1 ( ) log 1 β β B (81.) (log ) log e (8.) logβ Annex 10, page 17

18 Annex 10, page 18 of 19 β = β 0 μ μ % (8.) μ : correcton for path geometry: 500 ae h te h re The value of μ shall not excee 1. (84.) τ (85.) μ : =.5 : s efne n equaton (.) an the value of shall not be allowe to reuce below.4 correcton for terran roughness: 1 for hm 10 m (86.) 5 exp ( hm 10) (4 6 I ) for hm 10 m I = mn ( lt lr, 40) km (87.) A g : total gaseous absorpton etermne from equaton (1.). 6.5 The overall precton The followng proceure shoul be apple to the results of the foregong calculatons for all paths. Calculate an nterpolaton factor, F j, to take account of the path angular stance: ( ) F j tanh.0 (88.) Θ = 0. ξ = 0.8 θ : path angular stance (mra) (efne n Table ). Calculate an nterpolaton factor, F k, to take account of the great crcle path stance: ( sw) Fk tanh.0 (89.) sw : great crcle path length (km) (efne n Table ) sw : fxe parameter etermnng the stance range of the assocate blenng, set to 0 κ : fxe parameter etermnng the blenng slope at the ens of the range, set to 0.5. Calculate a notonal mnmum basc transmsson loss, L mnb0p (B) assocate wth lne-of-sght propagaton an over-sea sub-path ffracton. Annex 10, page 18

19 Annex 10, page 19 of 19 Lb0 p (1) Lp for p 0 Lmnb 0 p B (90.) Lb50 ( Lb0 (1) Lp Lb50) F for p 0 L b0p : notonal lne-of-sght basc transmsson loss not exceee for p% tme, gven by equaton (7.) L b0 : notonal lne-of-sght basc transmsson loss not exceee for % tme, gven by equaton (8.) L p : ffracton loss not exceee for p% tme, calculate usng the metho n 6.. Calculate a notonal mnmum basc transmsson loss, L mnbap (B), assocate wth lne-of-sght an transhorzon sgnal enhancements: L L ba b0 p L mnbap ln exp exp B (91.) L ba : uctng/layer reflecton basc transmsson loss not exceee for p% tme, gven by equaton (71.) L b0p : notonal lne-of-sght basc transmsson loss not exceee for p% tme, gven by equaton (7.) η =.5 Calculate a notonal basc transmsson loss, L ba (B), assocate wth ffracton an lne-ofsght or uctng/layer-reflecton enhancements: Lb Lba Lmnbap ( Lb Lmnbap ) Fk for for Lmnbap Lmnbap Lb B (9.) Lb L b : basc transmsson loss for ffracton not exceee for p% tme from equaton (58.). F k : nterpolaton factor gven by equaton (89.) accorng to the values of p an 0. Calculate a mofe basc transmsson loss, L bam (B), whch takes ffracton an lne-of-sght or uctng/layer-reflecton enhancements nto account L ) bam Lba ( Lmnb 0 p Lba Fj B (9.) Calculate the fnal basc transmsson loss not excee for p% tme, L b (B), as gven by: 0. L s 0. L L bam b 5log B (94.) Annex 10, page 19