ETSI ETS 300 579 ed.3 (1995-10)

SLOVENSKI STANDARD
SIST ETS 300 579 E3:2003
01-december-2003
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European digital cellular telecommunications system (Phase 2); Radio subsystem
synchronization (GSM 05.10)
Ta slovenski standard je istoveten z: ETS 300 579 Edition 3
ICS:
33.070.50 Globalni sistem za mobilno Global System for Mobile
telekomunikacijo (GSM) Communication (GSM)
SIST ETS 300 579 E3:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 579 E3:2003
EUROPEAN ETS 300 579
TELECOMMUNICATION September 1995
STANDARD Third Edition
Source: ETSI TC-SMG Reference: RE/SMG-020510PR2
ICS: 33.060.50
European digital cellular telecommunications system, Global System for Mobile communications
Key words:
(GSM)
European digital cellular telecommunications system (Phase 2);
Radio subsystem synchronisation
(GSM 05.10)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16
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 1995. All rights reserved.
New presentation - see History box

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ETS 300 579: September 1995 (GSM 05.10 version 4.6.0)
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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ETS 300 579: September 1995 (GSM 05.10 version 4.6.0)
Contents
Foreword .5
1.1 Scope .7
1.2 Normative references.7
1.3 Definitions and abbreviations .7
2 General description of synchronization system.8
3 Timebase Counters.8
4 Timing of Transmitted Signals.8
5 BS Requirements for Synchronization .9
6 MS Requirements for Synchronization.9
Annex A (normative): Additional requirements for pseudo-synchronisation, synchronised
handovers and pseudo-synchronised handovers.12
A1 General descriptions and definitions .12
A1.1 Conventions.12
A1.2 Definitions .12
A1.3 Details of operations .12
A2 BTS requirements .13
A2.1 The pseudo-synchronisation scheme.13
A2.2 The synchronisation scheme .13
A3 MS requirements.13
History.15

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ETS 300 579: September 1995 (GSM 05.10 version 4.6.0)
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 synchronisation of the Radio sub-system within the European
digital cellular telecommunications system (Phase 2). This ETS does not define the synchronisation
algorithms implemented in the Mobile Station (MS) and Base Station System (BSS).
This third edition of the ETS is a result of further work carried out by TC-SMG and correspond to GSM
technical specification, GSM 05.10 version 4.6.0.
The specification from which this ETS has been derived was originally based on CEPT documentation,
hence the presentation of this ETS is not in accordance with the ETSI/PNE rules.
Reference is made within this ETS to GSM Technical Specifications (GSM-TSs) (NOTE).
NOTE: TC-SMG has produced documents which give the technical specifications for the
implementation of the European digital cellular telecommunications system.
Historically, these documents have been identified as GSM Technical Specifications
(GSM-TSs). These TSs may have subsequently become I-ETSs (Phase 1), or ETSs
(Phase 2), whilst others may become ETSI Technical Reports (ETRs). GSM-TSs are,
for editorial reasons, still referred to in GSM ETSs.
Transposition dates
Date of adoption of this ETS: 30 September 1995
Date of latest announcement of this ETS (doa): 31 December 1995
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 June 1996
Date of withdrawal of any conflicting National Standard (dow): 30 June 1996

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ETS 300 579: September 1995 (GSM 05.10 version 4.6.0)
1.1 Scope
This European Telecommunications 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 Station (BS) 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 100): "European digital cellular telecommunication system
(Phase 2); Abbreviations and acronyms".
[2] GSM 04.08 (ETS 300 557): "European digital cellular telecommunication system
(Phase 2); Mobile radio interface layer 3 specification".
[3] GSM 05.02 (ETS 300 574): "European digital cellular telecommunication system
(Phase 2); Multiplexing and multiple access on the radio path".
[4] GSM 05.05 (ETS 300 577): "European digital cellular telecommunication system
(Phase 2); Radio transmission and reception".
[5] GSM 05.08 (ETS 300 578): "European digital cellular telecommunication system
(Phase 2); Radio subsystem link control".
[6] GSM 03.30 (ETR 103): "European digital cellular telecommunication system
(Phase 2); Radio network planning aspects".
1.3 Definitions and abbreviations
In addition to those below, Abbreviations used in this ETS are listed in GSM 01.04.
BS Base Station
Timing Advance: A signal sent by the BS to the MS which the MS uses to advance its timings
of transmissions to the BS 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 BS: The BS 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 BS 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 (ie 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.

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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 BS sends signals on the BCCH to enable the MS to synchronize itself to the BS and if necessary
correct its frequency standard to be in line with that of the BS. The signals sent by the BS 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 BS 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 BS.
The MS times its transmissions to the BS in line with those received from the BS. The BS sends to each
MS a "timing advance" parameter according to the perceived round trip propagation delay BS-MS-BS. The
MS advances its timing by this amount, with the result that signals from different MS's arriving at the BS
and compensated for propagation delay. This process is called "adaptive frame alignment".
Additionally, synchronisation functions may be implemented in both the MS and the BS to support the so-
called pseudo synchronisation 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-synchronisation scheme are included in Annex A.
3 Timebase Counters
3.1 The timing state of the signals transmitted by a BS 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 2048) - 1 = 2715647)
3.2 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 BS 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 section 3.2.
(When adjacent BS's are being monitored for handover purposes, the MS may choose to store the values
of QN, TN and FN for all the BS's whose synchronization bursts have been detected relative to QN, TN
and FN for its current serving BS).

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5 BS Requirements for Synchronization
The conditions under which the requirements of sections 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 The BS shall use a single frequency source of absolute accuracy better than 0.05 ppm for both RF
frequency generation and clocking the timebase. The same source shall be used for all carriers of
the BS.
5.2 It is optional whether the timebase counters of different BS's are synchronized together.
5.3 The channels of different carriers transmitted by a BS shall be synchronized together, ie controlled
by the same set of counters. The timing difference between the different carriers shall be less than
1/4 bit periods, measured at the BS antenna.
5.4 When the BS detects a random access CCCH transmission or a message with a long guard time
(eg handover acknowledgement) on a TCH, 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 BS
when applicable.
5.5 The maximum timing advance value shall be 63. If the BS measures a value larger than this, it shall
set the timing advance to 63. (GSM 03.30 defines how the PLMN deals with MS's where the delay
exceeds timing advance value 63.)
5.6 The BS shall thereafter continuously monitor the delay 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 MS. The delay shall be assessed in such a way that the assessment error (due to noise and
interference) is less than 1/2 bit periods for
...