ETSI TS V1.2.1 ( )

Transcription

1 TS V1.2.1 ( ) Tchnical Spcification GEO-Mobil Radio Intrfac Spcifications; Part 5: Radio intrfac physical layr spcifications; Sub-part 4: Modulation; GMR

2 2 TS V1.2.1 ( ) Rfrnc RTS/SES R1 Kywords GMR, MSS, MES, satllit, GSO, S-PCN, GSM, intrfac, mobil, modulation, radio 650 Rout ds Luciols F Sophia Antipolis Cdx - FRANCE Tl.: Fax: Sirt N NAF 742 C Association à but non lucratif nrgistré à la Sous-Préfctur d Grass (06) N 7803/88 Important notic Individual copis of th prsnt documnt can b downloadd from: Th prsnt documnt may b mad availabl in mor than on lctronic vrsion or in print. In any cas of xisting or prcivd diffrnc in contnts btwn such vrsions, th rfrnc vrsion is th Portabl Documnt Format (PDF). In cas of disput, th rfrnc shall b th printing on printrs of th PDF vrsion kpt on a spcific ntwork driv within Scrtariat. Usrs of th prsnt documnt should b awar that th documnt may b subjct to rvision or chang of status. Information on th currnt status of this and othr documnts is availabl at If you find rrors in th prsnt documnt, snd your commnt to: ditor@tsi.fr Copyright Notification No part may b rproducd xcpt as authorizd by writtn prmission. Th copyright and th forgoing rstriction xtnd to rproduction in all mdia. Europan Tlcommunications Standards Institut All rights rsrvd. DECT TM, PLUGTESTS TM and UMTS TM ar Trad Marks of rgistrd for th bnfit of its Mmbrs. TIPHON TM and th TIPHON logo ar Trad Marks currntly bing rgistrd by for th bnfit of its Mmbrs. 3GPP TM is a Trad Mark of rgistrd for th bnfit of its Mmbrs and of th 3GPP Organizational Partnrs.

3 3 TS V1.2.1 ( ) Contnts Intllctual Proprty Rights...4 Forword...6 Introduction Scop Rfrncs Dfinitions and abbrviations Burst structur Signal rprsntation Modulating symbol rat Start and stop of th burst Data bits and data symbols Normal burst π/4-cqpsk modulation Filtring Powr ramp π/4-cbit/sk modulation DKABs π/4-dbit/sk modulation BACH Modulation format Frquncy corrction burst Modulation format Modulation accuracy...16 Annx A (informativ): Bibliography...18 History...19

4 4 TS V1.2.1 ( ) Intllctual Proprty Rights IPRs ssntial or potntially ssntial to th prsnt documnt may hav bn dclard to. Th information prtaining to ths ssntial IPRs, if any, is publicly availabl for mmbrs and non-mmbrs, and can b found in SR : "Intllctual Proprty Rights (IPRs); Essntial, or potntially Essntial, IPRs notifid to in rspct of standards", which is availabl from th Scrtariat. Latst updats ar availabl on th Wb srvr ( Th attntion of has bn drawn to th Intllctual Proprty Rights (IPRs) listd blow which ar, or may b, or may bcom, Essntial to th prsnt documnt. Th IPR ownr has undrtakn to grant irrvocabl licncs, on fair, rasonabl and non-discriminatory trms and conditions undr ths IPRs pursuant to th IPR Policy. Furthr dtails prtaining to ths IPRs can b obtaind dirctly from th IPR ownr. Th prsnt IPR information has bn submittd to and pursuant to th IPR Policy, no invstigation, including IPR sarchs, has bn carrid out by. No guarant can b givn as to th xistnc of othr IPRs not rfrncd in SR (or th updats on th Wb srvr) which ar, or may b, or may bcom, ssntial to th prsnt documnt. IPRs: Projct Company Titl Country of Origin Patnt n Countris Applicabl TS V1.1.1 Digital Voic US US 5,226,084 US Systms Inc TS V1.1.1 Digital Voic US US 5,715,365 US Systms Inc TS V1.1.1 Digital Voic US US 5,826,222 US Systms Inc TS V1.1.1 Digital Voic US US 5,754,974 US Systms Inc TS V1.1.1 Digital Voic Systms Inc US US 5,701,390 US IPR Ownr: Contact: Digital Voic Systms Inc On Van d Graaff Driv Burlington, MA USA John C. Hardwick Tl.: Fax: Projct Company Titl Country of Origin Patnt n Countris Applicabl TS V1.1.1 Ericsson Mobil Improvmnts in, or in rlation GB GB GB Communication to, qualizrs TS V1.1.1 Ericsson Mobil Powr Boostr GB GB GB Communication TS V1.1.1 Ericsson Mobil Rcivr Gain GB GB GB Communication TS V1.1.1 Ericsson Mobil Communication Transmittr Powr Control for Radio Tlphon Systm GB GB GB IPR Ownr: Ericsson Mobil Communications (UK) Limitd Th Kytch Cntr, Ashwood Way Basingstok Hampshir RG23 8BG Unitd Kingdom

5 5 TS V1.2.1 ( ) Contact: John Watson Tl.: Projct Company Titl Country of Origin Patnt n Countris Applicabl TS V1.1.1 Hughs Ntwork Systms US Pnding US IPR Ownr: Contact: Hughs Ntwork Systms Exploration Lan Grmantown, Maryland USA John T. Whlan Tl: Fax: Projct Company Titl Country of Origin Patnt n Countris Applicabl TS V1.1.1 Lockhd Martin Global Tlcommunic. Inc 2.4-to-3 KBPS Rat Adaptation Apparatus for Us in Narrowband Data and Facsimil Communication US US 6,108,348 US TS V1.1.1 TS V1.1.1 TS V1.1.1 TS V1.1.1 TS V1.1.1 TS V1.1.1 Lockhd Martin Global Tlcommunic. Inc Lockhd Martin Global Tlcommunic. Inc Lockhd Martin Global Tlcommunic. Inc Lockhd Martin Global Tlcommunic. Inc Lockhd Martin Global Tlcommunic. Inc Lockhd Martin Global Tlcommunic. Inc Systms Cllular Spaccraft TDMA Communications Systm with Call Intrrupt Coding Systm for Maximizing Traffic ThroughputCllular Spaccraft TDMA Communications Systm with Call Intrrupt Coding Systm for Maximizing Traffic Throughput Enhancd Accss Burst for Random Accss Channls in TDMA Mobil Satllit Systm Spaccraft Cllular Communication Systm Spaccraft Cllular Communication Systm Spaccraft Cllular Communication Systm with Mutual Offst High-Margin Forward Control Signals Spaccraft Cllular Communication Systm with Spot Bam Pairing for Rducd Updats US US 5,717,686 US US US 5,875,182 US US 5,974,314 US US US 5,974,315 US US US 6,072,985 US US US 6,118,998 US IPR Ownr: Contact: Lockhd Martin Global Tlcommunications, Inc. 900 Forg Road Norristown, PA USA R.F. Francios Tl.: Fax:

6 6 TS V1.2.1 ( ) Forword This Tchnical Spcification (TS) has bn producd by Tchnical Committ Satllit Earth Stations and Systms (SES). Th contnts of th prsnt documnt ar subjct to continuing work within TC-SES and may chang following formal TC-SES approval. Should TC-SES modify th contnts of th prsnt documnt, it will thn b rpublishd by with an idntifying chang of rlas dat and an incras in vrsion numbr as follows: Vrsion 1.m.n whr: th third digit (n) is incrmntd whn ditorial only changs hav bn incorporatd in th spcification; th scond digit (m) is incrmntd for all othr typs of changs, i.. tchnical nhancmnts, corrctions, updats, tc. Th prsnt documnt is part 5, sub-part 4 of a multi-part dlivrabl covring th GEO-Mobil Radio Intrfac Spcifications, as idntifid blow: Part 1: Part 2: Part 3: Part 4: Part 5: "Gnral spcifications"; "Srvic spcifications"; "Ntwork spcifications"; "Radio intrfac protocol spcifications"; "Radio intrfac physical layr spcifications"; Sub-part 1: "Physical Layr on th Radio Path: Gnral Dscription; GMR "; Sub-part 2: "Multiplxing and Multipl Accss; Stag 2 Srvic Dscription; GMR "; Sub-part 3: "Channl Coding; GMR "; Sub-part 4: "Modulation; GMR "; Sub-part 5: "Radio Transmission and Rcption; GMR "; Sub-part 6: "Radio Subsystm Link Control; GMR "; Sub-part 7: "Radio Subsystm Synchronization; GMR "; Part 6: Part 7: "Spch coding spcifications"; "Trminal adaptor spcifications".

7 7 TS V1.2.1 ( ) Introduction GMR stands for GEO (Gostationary Earth Orbit) Mobil Radio intrfac, which is usd for mobil satllit srvics (MSS) utilizing gostationary satllit(s). GMR is drivd from th trrstrial digital cllular standard GSM and supports accss to GSM cor ntworks. Du to th diffrncs btwn trrstrial and satllit channls, som modifications to th GSM standard ar ncssary. Som GSM spcifications ar dirctly applicabl, whras othrs ar applicabl with modifications. Similarly, som GSM spcifications do not apply, whil som GMR spcifications hav no corrsponding GSM spcification. Sinc GMR is drivd from GSM, th organization of th GMR spcifications closly follows that of GSM. Th GMR numbrs hav bn dsignd to corrspond to th GSM numbring systm. All GMR spcifications ar allocatd a uniqu GMR numbr as follows: GMR-n xx.zyy whr: - xx.0yy (z = 0) is usd for GMR spcifications that hav a corrsponding GSM spcification. In this cas, th numbrs xx and yy corrspond to th GSM numbring schm. - xx.2yy (z = 2) is usd for GMR spcifications that do not corrspond to a GSM spcification. In this cas, only th numbr xx corrsponds to th GSM numbring schm and th numbr yy is allocatd by GMR. - n dnots th first (n = 1) or scond (n = 2) family of GMR spcifications. A GMR systm is dfind by th combination of a family of GMR spcifications and GSM spcifications as follows: If a GMR spcification xists it taks prcdnc ovr th corrsponding GSM spcification (if any). This prcdnc rul applis to any rfrncs in th corrsponding GSM spcifications. NOTE: Any rfrncs to GSM spcifications within th GMR spcifications ar not subjct to this prcdnc rul. For xampl, a GMR spcification may contain spcific rfrncs to th corrsponding GSM spcification. If a GMR spcification dos not xist, th corrsponding GSM spcification may or may not apply. Th applicability of th GSM spcifications is dfind in GMR [2].

8 8 TS V1.2.1 ( ) 1 Scop Th prsnt documnt dfins th modulation usd within th GMR-1 Mobil Satllit Systm. It includs th various modulation formats that ar rquird for diffrnt physical channl typs. It also dfins th concpt of th transmission burst and th mapping of modulatd symbols to th burst, dscribs th rquird transmit filtring in gnral trms, and spcifis th modulation accuracy. 2 Rfrncs Th following documnts contain provisions which, through rfrnc in this txt, constitut provisions of th prsnt documnt. Rfrncs ar ithr spcific (idntifid by dat of publication and/or dition numbr or vrsion numbr) or non-spcific. For a spcific rfrnc, subsqunt rvisions do not apply. For a non-spcific rfrnc, th latst vrsion applis. [1] GMR ( TS ): "GEO-Mobil Radio Intrfac Spcifications; Part 1: Gnral spcifications; Sub-part 1: Abbrviations and acronyms; GMR ". [2] GMR ( TS ): "GEO-Mobil Radio Intrfac Spcifications; Part 1: Gnral spcifications; Sub-part 2: Introduction to th GMR-1 Family; GMR ". [3] GMR ( TS ): "GEO-Mobil Radio Intrfac Spcifications; Part 5: Radio intrfac physical layr spcifications; Sub-part 2: Multiplxing and Multipl Accss; Stag 2 Srvic Dscription; GMR ". [4] GMR ( TS ): "GEO-Mobil Radio Intrfac Spcifications; Part 5: Radio intrfac physical layr spcifications; Sub-part 5: Radio Transmission and Rcption; GMR ". 3 Dfinitions and abbrviations For th purposs of th prsnt documnt, th trms, dfinitions and abbrviations givn in GMR [1] apply. 4 Burst structur 4.1 Signal rprsntation All transmittd signals s(t) ar rprsntd as basband complx signals x(t). Th actual transmittd signal may b drivd from its basband rprsntation as follows: s( t) = R j2πft ( x( t) ) whr f is th carrir frquncy, and R rprsnts th ral part of a complx numbr. 4.2 Modulating symbol rat Th modulating symbol rat is 23,4 ksymbol/s for all burst typs, xcpt for th Broadcasting Alrt Channl (BACH). Th symbol priod T is dfind as 1/23,4 ms. For BACH, th symbol rat is 300 symbol/s (1 200 bit/s).

9 9 TS V1.2.1 ( ) 4.3 Start and stop of th burst Thtimintrval[0,N(39T)] is th burst tim window whr N = 2, 3, 4, 6, 9, corrsponding to th burst typs dfind in GMR [3]. Th tim intrval [2,5T, N(39T)-2,5T] is th burst tim window corrsponding to th activ part of this burst. Th contnt of this part corrsponds to data symbols, i.. rfrnc and fr symbols. Th rmaining tim corrsponds to th guard intrvals (s GMR [3]). Ths guard intrvals corrspond to th transition from no signal to a continuous carrir and vic-vrsa. 4.4 Data bits and data symbols Thr ar 78N binary data bits dfind in {0,1} in ach burst for π/4-cqpsk (Cohrnt Quadratur Phas-Shift Kying) modulation and 39N binary bits for π/4-dbit/sk (Diffrntial Binary Phas-Shift Kying) and π/4-cbit/sk (Cohrnt Binary Phas-Shift Kying) modulation. For π/4-cqpsk, th burst bits ar rprsntd by [b 0 b 1 b 2 b 3 b 78N-2 b 78N-1 ], whr b 0 to b 4 and b 78N-5 to b 78N-1 ar guard bits. For π/4-dbit/sk and π/4-cbit/sk, th burst bits ar dnotd by [b 0 b 1 b 2 b 3 b 39N-2 b 39N-1 ]andb 0 to b 2 and b 39N-2 to b 39N-1 ar guard bits (total 5 guard bits). Whn modulating ths bits, w want to avoid grouping 1 guard bit with 1 information bit. Thus for π/4-cqpsk, th mapping rul from data bits to data symbols shall b: dk = ( b2 k 1b2 k ), k = 0,1,..., 39N which rsults in 39N+1 diffrnt symbols bing transmittd during 39NT (39N symbol duration). Howvr, th signals containd in th first and th last half symbol duration ar not actually transmittd according to th burst window dfinition in claus 4.3. To gnrat th first and th last symbols, on nds to us 2 dummy bits, which ar rprsntd by b -1 and b 78N Th dummy bits can b ithr of th two binary valus {0,1}. Figur 4.1 clarly illustrats th rlationship of data bits, dummy bits, data symbols, burst boundary, and symbol boundary for a π/4-cqpsk modulatd burst. Similarly, figur 4.2 shows th rlationship of th π/4-dbit/sk and π/4-cbit/sk bursts. According to figur 4.2, th mapping rul from data bits to data symbols for π/4-dbit/sk and π/4-cbit/sk bursts is: whr b 39N is considrd to b a dummy bit. dk = bk, k = 0,1,..., 39N Finally, th mapping of {d k } to th constllation points is dfind in clauss 5.1 and 6.1.

10 10 TS V1.2.1 ( ) guard bits information bits guard bits data bits b -1 b 0 b 1 b 2 b 3 b 4 b 5 b 6 b 78N-7 b 78N-6 b 78N-5 b 78N-4 b 78N-3 b 78N-2 b 78N-1 b 78N data symbols d 0 d 1 d 2 d 3 d 39N-3 d 39N-2 d 39N-1 d 39N data pulss 39NT burst boundary burst boundary NOTE: Th vrtical dottd lins rprsnt th symbol boundaris. Figur 4.1: Rlationship of data bits, data symbols, burst timing, and symbol timing for QPSK guard bits information bits guard bits data bits b 0 b 1 b 2 b 3 b 39N-3 b 39N-2 b 39N-1 b 39N data symbols d 0 d 1 d 2 d 3 d 39N-3 d 39N-2 d 39N-1 d 39N data pulss 39NT burst boundary burst boundary NOTE: Th vrtical dottd lins rprsnt th symbol boundaris. Figur 4.2: Rlationship of data bits, data symbols, burst timing, and symbol timing for BIT/SK

11 11 TS V1.2.1 ( ) 5 Normal burst All traffic and control channl bursts xcpt for DKAB, BACH, and FCCH ar calld normal bursts. Thy can b uplink or downlink bursts. 5.1 π/4-cqpsk modulation Normal bursts ar π/4-cqpsk (cohrnt quadratur phas shift kying) modulatd. Th complx nvlop of th transmittd signal is dfind as follows: jϕ = x( t) p( t) o α k h( t kt ) k = whr ϕ o is a random phas, h(t) is th impuls rspons of a shaping filtr dfind in claus 5.1.1, p(t)isthramp function as dfind in claus 5.1.2, and {α k } ar th modulating symbols dfind as follows: 0 k < 0 : k 39N : k > 39N: α k = 0 s tabl 5.1 α k = 0 whr N = 2, 3, 4, 6, 9 dpnding on th typ of th burst. Th modulating symbols ar drivd from th data symbols (fr and rfrnc symbols) according to tabl 5.1. Tabl 5.1: π/4-cqpsk modulation Data symbols (d k ) 00 jkπ 4 (1 + j0) 01 jkπ 4 (0 + j1) 11 j kπ 4 ( 1+ j0) 10 jkπ 4 (0 j1) Modulating symbols α k Filtring Th puls shaping filtr is th root raisd cosin filtr with a rolloff factor of 0,35. Its frquncy rspons H(f) is dfind by th following function: H ( f ) = 1 2 π 1 sin 1 0 ( 2 f T 1) 0,7 0,325 for 0 < f < T 0,325 0,675 for f T T 0,675 for f > T

12 12 TS V1.2.1 ( ) Th impuls rspons h(t), th invrs Fourir transform of H(f), is writtn as: Powr ramp 5 2 T 1,35πt 5T 0,65πt h( t) = 7 cos + sin 2 5 T 7t T 2 π T t 7 Th powr ramp function shall mt th GMR [4] spcification. NOTE: An approach to mting th GMR [4] spcification is th convolution of a Blackman window of appropriat duration x (th duration may b diffrnt for diffrnt typs of bursts) and a rctangular-shapd function of duration ( Tb x) ms., whr T b is th burst lngth in ms. An altrnativ approach is to st all th guard modulating symbols (α 0, α 1, α 2, α 3N-2, α 3N-1, α 3N ) to zro. In this way, th ramp ffct is achivd by th filtr rspons dfind in claus π/4-cbit/sk modulation Som of th normal bursts ar π/4-cbit/sk (cohrnt binary phas-shift kying) modulatd. Th complx nvlop of th transmittd signal is dfind as for th π/4-cqpsk cas. π/4-cbit/sk bursts ar considrd as a spcial cas of π/4-cqpsk with th following corrspondnc. Tabl 5.2: π/4-cbit/sk modulation Data symbols (d k ) 0 jkπ 4 (1 + j0) 1 j kπ 4 ( 1+ j0) Modulating symbols α k

13 13 TS V1.2.1 ( ) 6 DKABs 6.1 π/4-dbit/sk modulation Dual Kp-Aliv Bursts (DKABs) ar π/4-dbit/sk modulatd. Th complx nvlop of th transmittd signal is dfind as follows: = jϕ p( t) k = x( t) o α k h( t kt ) whr ϕ o is a random phas, h(t) is th impuls rspons of a shaping filtr dfind in claus 5.1.1, p(t)isthramp function as dfind in claus 1.2, and {α k } ar th modulating symbols dfind as follows: k < 3 + q / 2 : k = 3 + q / 2 : 3 + q / 2 < k 7 + q / 2 : 7 + q/ 2 < k < 62 + q/ 2 : k = 62 + q / 2 : 62 + q / 2 < k 66 + q / 2 : k > 66 + q / 2 : α k = 0 α k = 1 s tabl 6.1 α k = 0 α k = 1 s tabl 6.1 α k = 0 whr q shall b vn and 0 < q < 95 as xplaind in GMR [3]. Th modulating symbols ar drivd from th data symbols (fr and rfrnc symbols) according to tabl 6.1. Tabl 6.1: π/4-dbit/sk modulation Data symbols d k Modulating symbols α k 0 jπ 4 α k 1 1 3π 4 α k 1 j α3+ q 2 and α62+ q 2 rprsnt th first and th scond rfrnc symbols rspctivly.

14 14 TS V1.2.1 ( ) 7 BACH Th Alrt channl (BACH) data consists of a 36-bit mssag that addrsss th intndd trminal notifying th usr of a call attmpt. Th mssag bits ar ncodd to output 60 codd bits. Each BACH burst of two slots carris 4 codd bits. 15 BACH bursts ar rquird to transmit a complt alrting mssag. 7.1 Modulation format BACH bursts ar 6PSK modulatd. Th complx nvlop of th transmittd signal is dfind as follows: = jϕ x( t) p( t) o α k h( t kt ) k = whr ϕ o is a random phas, h(t) is th impuls rspons of a shaping filtr dfind in claus 5.1.1, p(t)isthramp function as dfind in claus 5.1.2, and {α k } ar th modulating symbols dfind as follows: 0 k < 0 : k k > 78 : 78 : α k = 0 s tabl 7.1 α k = 0 Th modulating symbols ar drivd from a BACH squnc {v k } according to tabl 7.1. Tabl 7.1: HPSK modulation Squnc valus (v k ) 0 j0 1 j2π / j2π / 3 jπ 4 jπ / jπ / Modulating symbols α k Th squnc valu v k is uniquly dfind by on of th 16 squncs S j in tabl 7.2 as follows: v k {any of = S j ( i), {any of (0,1, (0,1, 2, 3, 4, 5)}, 2, 3, 4, 5)}, j = 0, 1,...,15; k = 0,1, 2. k = 3, 4,...,74. k = 75,76,77,78. whr I is computd by: and x i = k 3 4 taks th intgr part of x. i taks numbrs from {0, 1,, 17} for th rang of k valus.

15 15 TS V1.2.1 ( ) Tabl 7.2: Dfinition of 16 BACH squncs Squncs Squnc lmnts (18 pr ach squnc) S S S S S S S S S S S S S S S S From th abov quation, v k for k =0,1,2andk = 75, 76, 77, 78 also blongs to {0, 1, 2, 3, 4, 5}. Th spcific squnc pattrns can b arbitrarily dfind. Th mapping from th 4 codd bits to on of th 16 squncs S j is dfind in tabl 7.3. Tabl 7.3: Codd bits to S j mapping Codd bits Squncs S j 0000 S S S S S S S S S S S S S S S S 15

16 16 TS V1.2.1 ( ) 8 Frquncy corrction burst 8.1 Modulation format Frquncy corrction burst is a ral chirp signal spanning thr slots. Th complx nvlop of th transmittd burst is dfind as follows: jϕ 2 2 [ o 2 cos( 0,64 ( t 58,5T ) /(117T ))] x( t) = p( t) π whr ϕ o is a random phas and p(t) is th ramp function as dfind in claus This signal dfins th chirp swping rang as (-7,488 khz, 7,488 khz). 9 Modulation accuracy Modulation accuracy is dfind as th diffrnc btwn th actual transmittd signal and th thortical signal dfind in prvious clauss. Modulation accuracy is masurd in trms of th rror vctor magnitud from th transmittd symbol to th thortical point in th constllation at th optimum symbol sampling points. Th transmit accuracy rquirmnts ar: th root-man-squar (rms) rror vctor magnitud ovr th ntir burst shall b lss than 0,09; th rms rror vctor magnitud ovr th first ight symbols of th burst shall b lss than 0,18. Th rms rror vctor magnitud, th masur of modulation accuracy, shall b computd as follows: Obsrving an idal transmittr through an idal squar root raisd-cosin rcivr filtr at th corrct sampling instants on symbol apart would rsult in th squnc of valus givn (for π/4-cqpsk) by: S [ 4 ( ) 2 ( k j kπ B k π ) S ] R + = whr S R is a rfrnc symbol position dfind by th transmittd sync pattrn and k = 0, 1,..., 39N, S(k) = 1 and B(k) = 0, 1, 2, 3 according to tabl 9.1. For π/4-dbit/sk, S( k) = S( k 1) [ π / 4+ B( k) π / 2] j whr k = 0, 1,..., 39N, S(k) = 1 and B(k) = 0, 2 according to tabl 9.2. Tabl 9.1: Drivation of B(k) for π/4-cqpsk Data symbols (d k ) B(k) Tabl 9.2: Drivation of B(k) for π/4-dbit/sk Data symbols (d k ) B(k)

17 17 TS V1.2.1 ( ) Th idal transmit and rciv filtrs in cascad form a raisd cosin Nyquist filtr having an impuls rspons going through zro at symbol priod intrvals so thr is no intrsymbol intrfrnc at th idal sampling points. Thrfor, th idal signal sampls tak on on of th ight valus dfind abov, at th output of th rciv filtr. Lt Z(k) b th complx vctors producd by obsrving th ral transmittr through an idal masuring rcivr filtr at instants k, on symbol priod apart. With S(k) dfind as abov, th transmittr is modlld as: whr: { C + C [ S( k) E( k ]} W k Z k) = ) ( ) W = dr + jdσ accounts for both a frquncy offst giving "dσ" radians pr symbol phas rotation and an amplitud chang of "dr" nprs pr symbol; 2) C 0 is a constant origin offst rprsnting carrir fdthrough at th transmittr; 3) C 1 is a complx constant rprsnting th arbitrary phas and output powr of th transmittr; and 4) E(k) is th rsidual vctor rror on sampl S(k). Th sum squar vctor rror is thn: MAX MAX 2 E( k ) = k = MIN k = MIN k [ Z ( k) W C0 ] C1 S ( k ) 2 C 0, C 1,andW will b chosn to minimiz this xprssion and ar thn usd to comput th individual vctor rrors E(k) on ach symbol. Th symbol timing phas of th rcivr output sampls usd to comput th vctor rror will also b chosn to giv th lowst valu. Th valus of MAX and MIN ar th last and first maximum ffct points in th (sgmnt of th) burst undr masurmnt. Th rms vctor rror is thn computd as th squar root of th sum-squar vctor dividd by th numbr of symbols in th sgmnt undr masurmnt. Th rsult is thn normalizd rlativ to th symbol magnitud. Th abov rquirmnts shall b satisfid ovr th xtrm st of nvironmntal conditions spcifid in annx B of GMR [4]. If th MES is opratd outsid th rang of xtrm nvironmntal conditions, th EVM of th whol burst shall not xcd 0,12, and th EVM of th first ight symbols of th burst shall not xcd 0,24.

18 18 TS V1.2.1 ( ) Annx A (informativ): Bibliography GMR ( TS ): "GEO-Mobil Radio Intrfac Spcifications; Part 5: Radio intrfac physical layr spcifications; Sub-part 1: Physical Layr on th Radio Path: Gnral Dscription; GMR ".

19 19 TS V1.2.1 ( ) History V1.1.1 March 2001 Publication V1.2.1 April 2002 Publication Documnt history