1、ETSI EN 300 912 V6.6.1 (2001-05) European Standard (Telecommunications series) Digital cellular telecommunications system (Phase 2+); Radio subsystem synchronization (GSM 05.10 version 6.6.1 Release 1997) (GSM 05.10 version 6.6.1 Release 1997) 2 ETSI EN 300 912 V6.6.1 (2001-05) Reference REN/SMG-020
2、51 OQ6R4 Keywords Digital cellular telecommunications system, Global System for Mobile communications (GSM) ETSI 650 Route des Lucioles F-O6921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 Siret No 348 623 562 O0017 - NAF 742 C Association but non lucratif enregistr
3、e la Sous-prfecture de Grasse (06) No 7803/88 Important notice Individual copies of the present document can be downloaded from: htt!x/w.ettlsi. orq The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents
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5、ay be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at If you find errors in the present document, send your comment to: ed itoretsi .fr Copyright Notification No part may be reproduced except as authorized by written permiss
6、ion. The copyright and the foregoing restriction extend to reproduction in all media. O European Telecommunications Standards Institute 2001. All rights reserved. ETSI (GSM 05.10 version 6.6.1 Release 1997) 3 ETSI EN 300 912 V6.6.1 (2001-05) Contents Intellectual Property Rights 5 Foreword 5 1 1.1 1
7、.2 2 3 3.1 3.2 4 5 5.1 5.2 5.3 5.4 5.5 5.6 5.6.1 5.6.2 5.6.3 5.7 5.8 6 6.1 6.2 6.3 6.4 6.5 6.5.1 6.5.2 6.6 6.7 6.8 6.9 6.10 6.11 Scope 6 References 6 Definitions and abbreviations 6 General description of synchronization system 7 Timebase counters 7 Timing state of the signals . 7 Relationship betwe
8、en counters . 8 Timing of transmitted signals 8 BTS Requirements for Synchronization 8 Frequency source 8 Timebase counters . 8 Internal BTS carrier timing 8 Initial Timing advance estimation 9 Maximum timing advance value 9 Delay tracking . 9 For circuit switched channels . 9 For packet switched ch
9、annels . 9 Delay assessment error . 9 Timeslot length . 9 Range of Timing advance 9 MS carrier ftequency . 10 MS Requirements for Synchronization 10 Internal timebase . 10 Assessment of BTS timing . 10 Timing of transmission 10 Application of Timing Advance . 10 For circuit switched channels . 10 Fo
10、r packet switched channels . 11 Access to a new BTS . 11 Temporary loss of signal 12 Timing of intracell channel change 12 Application of new Timing Advance value 12 Definition of ?ready to transmit within x ms“ . 12 Definition of additional reaction times for GPRS mobile stations . 12 6.11.1 6.11.2
11、 6.11.3 6.11.4 Annex A (normative): handovers and pseudo-synchronized handovers . 14 A . 1 General descriptions and definitions 14 A.l.l Conventions 14 A.1.2 Definitions 14 Details of operations 14 A.2 BTS requirements . 15 The pseudo-synchronization scheme 15 BTS a time difference estimate . 15 The
12、 reception epoch criterion . 15 Uplink and downlink assignment reaction times . 12 Change in channel coding scheme commanded by network . 12 Contention resolution reaction time 13 Reaction time in response to other commanding messages 13 Additional requirements for pseudo-synchronization, synchroniz
13、ed A.1.3 A.2.1 A.2.1.1 A.2.1.2 ETSI (GSM 05.10 version 6.6.1 Release 1997) 4 ETSI EN 300 912 V6.6.1 (2001-05) A.2.1.3 Pseudo-synchronized handover 15 The synchronization requirement . 15 A.3 MS requirements 16 Provision of time difference information 16 After each successful handover 16 Synchronized
14、 or a pseudo synchronized handover 16 Change Request History 17 A.2.2 A.3.1 A.3.2 A.3.3 Annex B (informative): History . 18 ETSI (GSM 05.10 version 6.6.1 Release 1997) 5 ETSI EN 300 912 V6.6.1 (2001-05) Intellectual Property Rights IPRs essential or potentially essential to the present document may
15、have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR O00 3 14: “Intellectual Property Rights (IPRs); Essential, orpotentially Essential, IPRs notjed to ETSI in respect OfETSIstandar
16、ds“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (htt:/!wvw.etsi ordj r). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not ref
17、erenced in ETSI SR O00 3 14 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Special Mobile Group (SMG). The present document defin
18、es the requirements for synchronization on the GSM radio sub-system of the digital mobile cellular and personal communication systems operating in the 900 MHz and 1 800 MHz band (GSM 900 and DCS 1 SOO). The contents of the present document are subject to continuing work within SMG and may change fol
19、lowing formal SMG approval. Should SMG modi6 the contents of the present document it will then be republished by ETSI with an identifiing change of release date and an increase in version number as follows: Version 6.x.y where: 6 indicates release 1997 of GSM Phase 2+ x the second digit is increment
20、ed for all changes of substance, i.e. technical enhancements, corrections, updates, etc. y the third digit is incremented when editorial only changes have been incorporated in the specification. National transposition dates Date of adoption of this EN: Date of latest announcement of this EN (doa): D
21、ate of latest publication of new National Standard or endorsement of this EN (dop/e): Date of withdrawal of any conflicting National Standard (dow): 18 May 2001 3 1 August 200 1 28 February 2002 28 February 2002 ETSI (GSM 05.10 version 6.6.1 Release 1997) 6 ETSI EN 300 912 V6.6.1 (2001-05) 1 Scope T
22、he present document defines the requirements for synchronization on the GSM radio sub-system. (However, it does not define the synchronization algorithms to be used in the Base Transceiver Station (BTS) and Mobile Station (MS). These are up to the manufacturer to spec.) 1 .I References The following
23、 documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. For a specific reference, subsequent revisions do not apply. F
24、or a non-specific reference, the latest version applies. A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. For this Release 1997 document, references to GSM documents are for Release 1997 versions (version 6.x.y). GSM O 1.04: “
25、Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms“. GSM 03.60: “Digital cellular telecommunications system (Phase 2+); General Packet Radio Service (GPRS); Service Description Stage 2“. GSM 03.64: “Digital cellular telecommunications system (Phase 2+); General Packet
26、Radio Service (GPRS); GPRS Radio Interface Stage 2“. GSM 04.08: “Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specification“. GSM 04.60: “Digital cellular telecommunications system (Phase 2+); General Packet Radio Service (GPRS); Mobile Station (MS) - Base St
27、ation System (BSS interface; Radio Link Control (RLC) and Medium Access Control (MAC) Layer Specification“. GSM 05.02: “Digital cellular telecommunications system (Phase 2+); Multiplexing and multiple access on the radio path“. GSM 05.05: “Digital cellular telecommunications system (Phase 2+); Radio
28、 transmission and reception“. GSM 05.08: “Digital cellular telecommunications system (Phase 2+); Radio subsystem link control“. GSM 03.30: “Digital cellular telecommunications system (Phase 2+); Radio network planning aspects“. Defi nit ions and ab brevi at ions In addition to those below, abbreviat
29、ions used in the present document are listed in GSM O 1.04. For the purposes of the present document, the following terms and definitions apply: BTS: Base Transceiver Station Timing Advance: signal sent by the BTS to the MS which the MS uses to advance its timings of transmissions to the BTS so as t
30、o compensate for propagation delay ETSI (GSM 05.10 version 6.6.1 Release 1997) 7 ETSI EN 300 912 V6.6.1 (2001-05) Quarter bit number: timing of quarter bit periods (12/13 ps) within a timeslot Timeslot number: timing of timeslots within a TDMA frame TDMA frame number: count of TDMA frames relative t
31、o an arbitrary start point Current Serving BTS: BTS on one of whose channels (TCH, DCCH, CCCH or PDCH) the MS is currently operating Timebase counters: set of counters which determine the timing state of signals transmitted by a BTS or MS MS timing offset: delay of the received signal relative to th
32、e expected signal from an MS at zero distance under static channel conditions with zero timing advance. This is accurate to *1 bit, and reported once per SACCH or after a RACH as. required (i.e. at the same rate as timing advance). For example, for an MS with a round trip propagation delay of P bits
33、, but with a timing advance of T bits, the reported timing offset will be P-T quantized to the nearest bit. For GPRS the MS timing offset is not reported Timing Advance Index: Timing Advance Index TAI used for GPRS, which determines the position of the subchannel on PTCCH (see GSM 05.02) used by the
34、 MS to send an access burst, from which the network can derive the timing advance 2 General description of synchronization system This clause gives a general description of the synchronization system. Detailed requirements are given in clauses 3 to 6. The BTS sends signals on the BCCH to enable the
35、MS to synchronize itself to the BTS and if necessary correct its frequency standard to be in line with that of the BTS. The signals sent by the BTS for these purposes are: a) frequency correction bursts; b) synchronization bursts. The timings of timeslots, TDMA frames, TCH frames and control channel
36、 frames are all related to a common set of counters which run continuously whether the MS and BTS are transmitting or not. Thus, once the MS has determined the correct setting of these counters, all its processes are synchronized to the current serving BTS. The MS times its transmissions to the BTS
37、in line with those received from the BTS. The BTS sends to each MS a “timing advance“ parameter (TA) according to the perceived round trip propagation delay BTS-MS-BTS. The MS advances its timing by this amount, with the result that signals from different MSs arriving at the BTS and compensated for
38、propagation delay. This process is called “adaptive frame alignment“. Additionally, synchronization functions may be implemented in both the MS and the BTS to support the so-called pseudo synchronization scheme. The support of this scheme is optional except that MS shall measure and report the Obser
39、ved Timing Difference (OTD), which is a mandatory requirement. The detailed specifications of the pseudo-synchronization scheme are included in annex A. 3 Timebase counters 3.1 Timing state of the signals The timing state of the signals transmitted by a BTS or MS is defined by the following counters
40、: - - - Quarter bit number QN (O - 624)- Bit number BN (O - 156); Timeslot number TN (O - 7); TDMA frame number FN (O to (26 x 51 x 2048) - 1 = 2715647). ETSI (GSM 05.10 version 6.6.1 Release 1997) 8 ETSI EN 300 912 V6.6.1 (2001-05) 3.2 Re1 at i o ns h i p between cou n t ers The relationship betwee
41、n these counters is as follows: - - - - QN increments every 12/13 ps; BN = Integer part of QN/4; TN increments whenever QN changes from count 624 to O; FN increments whenever TN changes from count 7 to O. 4 Timing of transmitted signals The timing of signals transmitted by the MS and BTS are defined
42、 in GSM 05.02. The MS can use the timing of receipt of the synchronization burst to set up its timebase counters as follows: QN is set by the timing of the training sequence; TN= O when the synch burst is received; FN= 51 (T3-T2) mod (26) + T3 + 51 x 26 x T1 when the synch burst is received, (where
43、T3 = (10 x T3) + 1, T1, T2 and T3 being contained in information fields in synchronization burst). Thereafter, the timebase counters are incremented as in clause 3.2. (When adjacent BTSs are being monitored for handover purposes, or for cell reselection purposes in group receive mode, the MS may cho
44、ose to store the values of QN, TN and FN for all the BTSs whose synchronization bursts have been detected relative to QN, TN and FN for its current serving BTS.) 5 BTS Requirements for Synchronization The conditions under which the requirements of clauses 5.4 and 5.6 must be met shall be 3 dB below
45、the reference sensitivity level in GSM 05.05 and 3 dB less carrier to interference ratio than the reference interference ratios in GSM 05.05. 5.1 Frequency source The BTS shall use a single frequency source of absolute accuracy better than 0,05 ppm for both RF frequency generation and clocking the t
46、imebase. The same source shall be used for all carriers of the BTS. 5.2 Timebase counters It is optional whether the timebase counters of different BTSs are synchronized together. 5.3 Internal BTS carrier timing The channels of different carriers transmitted by a BTS shall be synchronized together,
47、i.e. controlled by the same set of counters. The timing difference between the different carriers shall be less than 114 bit periods, measured at the BTS antenna. ETSI (GSM 05.10 version 6.6.1 Release 1997) 9 ETSI EN 300 912 V6.6.1 (2001-05) 5.4 Initial Timing advance estimation When the BTS detects
48、 an access burst transmission on RACH or PRACH, it shall measure the delay of this signal relative to the expected signal from an MS at zero distance under static channel conditions. This delay, called the timing advance, shall be rounded to the nearest bit period and included in a response from the
49、 BTS when applicable. 5.5 Maximum timing advance value The maximum timing advance value shall be 63. If the BTS measures a value larger than this, it shall set the timing advance to 63. (GSM 03.30 defines how the PLMN deals with MSs where the delay exceeds timing advance value 63 .) 5.6 Delay tracking 5.6.1 For circuit switched channels The BTS shall thereafter continuously monitor the delay of the normal bursts sent by from the MS. If the delay changes by more than one bit period, the timing advance shall be advanced or retarded 1 and the new value signalled to the M
