ETSI ETS 300 912 ed.1 (1997-05)

Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem synchronization (GSM 05.10 version 5.1.1)

DE/SMG-020510QR

Digitalni celični telekomunikacijski sistem (faza 2+) – Sinhronizacija radijskega podsistema (GSM 05.10, različica 5.1.1)

General Information

• Status: Published
• Publication Date: 02-Jun-1997
• Technical Committee: SMG 2 - Radio
• Current Stage: 12 - Completion
• Due Date: 09-May-1997
• Completion Date: 03-Jun-1997
• Ref Project: SIST ETS 300 912 E1:2003 - Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem synchronization (GSM 05.10 version 5.1.1)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 912 E1:2003
01-december-2003
'LJLWDOQLFHOLþQLWHOHNRPXQLNDFLMVNLVLVWHPID]D±6LQKURQL]DFLMDUDGLMVNHJD
SRGVLVWHPD*60UD]OLþLFD
Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem
synchronization (GSM 05.10 version 5.1.1)
Ta slovenski standard je istoveten z: ETS 300 912 Edition 1
ICS:
33.070.50 Globalni sistem za mobilno Global System for Mobile
telekomunikacijo (GSM) Communication (GSM)
SIST ETS 300 912 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 912 E1:2003

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SIST ETS 300 912 E1:2003
EUROPEAN ETS 300 912
TELECOMMUNICATION May 1997
STANDARD
Source: ETSI TC-SMG Reference: DE/SMG-020510QR
ICS: 33.020
Key words: Digital cellular telecommunications system, Global System for Mobile communications (GSM)
R
GLOBAL SYSTEM FOR
MOBILE COMMUNICATIONS
Digital cellular telecommunications system (Phase 2+);
Radio subsystem synchronization
(GSM 05.10 version 5.1.1)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail]
Tel.: [phone] - Fax: [phone]
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1997. All rights reserved.

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ETS 300 912 (GSM 05.10 version 5.1.1): May 1997
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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Contents
Foreword .5
1 Scope .7
1.2 Normative references .7
1.3 Definitions and abbreviations.7
2 General description of synchronization system.8
3 Timebase counters.8
3.1 Timing state of the signals.8
3.2 Relationship between counters.8
4 Timing of transmitted signals .8
5 BTS Requirements for Synchronization .9
5.1 Frequency source .9
5.2 Timebase counters .9
5.3 Internal BTS carrier timing .9
5.4 Timing advance estimation.9
5.5 Maximum timing advance value .9
5.6 Delay tracking .9
5.7 Timeslot length .9
5.8 Range of Timing advance.10
6 MS Requirements for Synchronization.10
6.1 MS carrier frequency.10
6.2 Internal timebase .10
6.3 Assessment of BTS timing .10
6.4 Timing of transmission.10
6.5 Application of Timing Advance .10
6.6 Access to a new BTS.11
6.7 Temporary loss of signal.11
6.8 Timing of intracell channel change .11
6.9 Application of new Timing Advance value .11
6.10 Definition of "ready to transmit within x ms".11
Annex A (normative): Additional requirements for pseudo-synchronization, synchronized handovers
and pseudo-synchronized handovers.12
A.1 General descriptions and definitions .12
A.1.1 Conventions.12
A.1.2 Definitions .12
A.1.3 Details of operations .12
A.2 BTS requirements .13
A.2.1 The pseudo-synchronization scheme .13
A.2.1.1 BTS a time difference estimate.13
A.2.1.2 The reception epoch criterion.13
A.2.1.3 Pseudo-synchronized handover.13
A.2.2 The synchronization requirement.13
A.3 MS requirements.13
A.3.1 Provision of time difference information .13
A.3.2 After each successful handover.13
A.3.3 Synchronized or a pseudo synchronized handover .14
History.15

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Foreword
This European Telecommunication Standard (ETS) has been produced by the Special Mobile Group
(SMG) Technical Committee (TC) of the European Telecommunications Standards Institute (ETSI).
This ETS defines 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 1 800).
This ETS is a GSM technical specification version 5, which incorporates GSM Phase 2+
enhancements/features to the version 4 GSM technical specification. The ETS from which this Phase 2+
ETS has evolved is Phase 2 GSM ETS 300 579 Edition 6 (GSM 05.10 version 4.9.0).
The contents of this ETS is subject to continuing work within TC-SMG and may change following formal
TC-SMG approval. Should TC-SMG modify the contents of this ETS, it will be resubmitted for OAP by
ETSI with an identifying change of release date and an increase in version number as follows:
Version 5.x.y
where:
y the third digit is incremented when editorial only changes have been incorporated in the
specification;
x the second digit is incremented for all other types of changes, i.e. technical enhancements,
corrections, updates, etc.
The specification from which this ETS has been derived was originally based on CEPT documentation,
hence the presentation of this ETS may not be entirely in accordance with the ETSI rules.
Transposition dates
Date of adoption: 18 April 1997
Date of latest announcement of this ETS (doa): 31 August 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 28 February 1998
Date of withdrawal of any conflicting National Standard (dow): 28 February 1998

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1 Scope
This European Telecommunication Standard (ETS) 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 specify.)
1.2 Normative references
This ETS incorporates by dated and undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this ETS only when incorporated in it by amendment or revision. For undated references, the
latest edition of the publication referred to applies.
[1] GSM 01.04 (ETR 350): "Digital cellular telecommunications system (Phase 2+);
Abbreviations and acronyms".
[2] GSM 04.08 (ETS 300 940): "Digital cellular telecommunications system
(Phase 2+); Mobile radio interface layer 3 specification".
[3] GSM 05.02 (ETS 300 908): "Digital cellular telecommunications system
(Phase 2+); Multiplexing and multiple access on the radio path".
[4] GSM 05.05 (ETS 300 910): "Digital cellular telecommunications system
(Phase 2+); Radio transmission and reception".
[5] GSM 05.08 (ETS 300 911): "Digital cellular telecommunications system
(Phase 2+); Radio subsystem link control".
[6] GSM 03.30 (ETR 364): "Digital cellular telecommunications system; Radio
network planning aspects".
1.3 Definitions and abbreviations
For the purposes of this ETS, the following definitions apply:
BTS: Base Transceiver Station.
Timing Advance: A signal sent by the BTS to the MS which the MS uses to advance its timings of
transmissions to the BTS so as to compensate for propagation delay.
Quarter bit number: The timing of quarter bit periods (12/13 μs) within a timeslot.
Timeslot number: The timing of timeslots within a TDMA frame.
TDMA frame number: The count of TDMA frames relative to an arbitrary start point.
Current Serving BTS: The BTS on one of whose channels (TCH, DCCH or CCCH) the MS is currently
operating.
Timebase counters: A set of counters which determine the timing state of signals transmitted by a BTS
or MS.
MS timing offset: The delay of the received signal relative to the 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, but with a timing advance of T bits, the reported timing
offset will be P-T quantized to the nearest bit.
Abbreviations used in this ETS are listed in GSM 01.04.

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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 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 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 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 MS's
arriving at the BTS and compensated for 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 Observed 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:
- Quarter bit number QN (0 - 624)- Bit number BN (0 - 156).
- Timeslot number TN (0 - 7).
- TDMA frame number FN (0 to (26 x 51 x 2 048) - 1 = 2715647).
3.2 Relationship between counters
The relationship between these counters is as follows:
- QN increments every 12/13 μs.
- BN = Integer part of QN/4.
- TN increments whenever QN changes from count 624 to 0.
- FN increments whenever TN changes from count 7 to 0.
4 Timing of transmitted signals
The timing of signals transmitted by the MS and BTS are defined 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 = 0 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 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 subclause 3.2.

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(When adjacent BTS's are being monitored for handover purposes, or for cell reselection purposes in
group receive mode, the MS may choose to store the values of QN, TN and FN for all the BTS's 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 subclauses 5.4 and 5.6 must be met shall be 3 dB below
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 Freque
...