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TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
GSM/EDGE Modulation
(3GPP TS 45.004 version 15.0.0 Release 15)
R
GLOBAL SYSTEM FOR
MOBILE COMMUNICATIONS
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3GPP TS 45.004 version 15.0.0 Release 15 1 ETSI TS 145 004 V15.0.0 (2018-07)
Reference
RTS/TSGR-0645004vf00
Keywords
GSM
ETSI
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ETSI
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3GPP TS 45.004 version 15.0.0 Release 15 2 ETSI TS 145 004 V15.0.0 (2018-07)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may 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 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
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 referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
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ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
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Foreword
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
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3GPP TS 45.004 version 15.0.0 Release 15 3 ETSI TS 145 004 V15.0.0 (2018-07)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 4
1 Scope . 5
1.1 References . 5
1.2 Abbreviations . 5
2 Modulation format for GMSK . 5
2.1 Modulating symbol rate . 5
2.2 Start and stop of the burst . 6
2.3 Differential encoding . 6
2.4 Filtering . 6
2.5 Output phase . 7
2.6 Modulation . 7
2.7 Overlaid CDMA . 8
3 Modulation format for 8PSK . 8
3.1 Modulating symbol rate . 8
3.2 Symbol mapping . 8
3.3 Start and stop of the burst . 9
3.4 Symbol rotation . 9
3.5 Pulse shaping . 9
3.6 Modulation . 10
4 Modulation format for 16QAM and 32QAM at the normal symbol rate . 10
4.1 Modulating symbol rate . 10
4.2 Symbol mapping . 10
4.3 Start and stop of the burst . 12
4.4 Symbol rotation . 13
4.5 Pulse shaping . 13
4.6 Modulation . 13
5 Modulation format for QPSK, 16QAM and 32QAM at the higher symbol rate . 13
5.1 Modulating symbol rate . 13
5.2 Symbol mapping . 13
5.3 Start and stop of the burst . 14
5.4 Symbol rotation . 14
5.5 Pulse shaping . 14
5.6 Modulation . 15
6 Modulation format for AQPSK . 15
6.1 Modulating symbol rate . 15
6.2 Symbol mapping . 15
6.3 Start and stop of the burst . 16
6.4 Symbol rotation . 17
6.5 Pulse shaping . 17
6.6 Modulation . 17
Annex A (normative): Tx filter coefficients for the spectrally wide pulse shape . 18
Annex B (informative): Change history . 19
History . 20
ETSI
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3GPP TS 45.004 version 15.0.0 Release 15 4 ETSI TS 145 004 V15.0.0 (2018-07)
Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
ETSI
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3GPP TS 45.004 version 15.0.0 Release 15 5 ETSI TS 145 004 V15.0.0 (2018-07)
1 Scope
The modulator receives the bits from the encryption unit, see 3GPP TS 45.001, and produces an RF signal. The filtering
of the Radio Frequency (RF) signal necessary to obtain the spectral purity is not defined, neither are the tolerances
associated with the theoretical filter requirements specified. These are contained in 3GPP TS 45.005.
1.1 References
The following 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.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 45.001: "Physical Layer on the Radio Path (General Description)".
[3] 3GPP TS 45.002: "Multiplexing and multiple access on the radio path".
[4] 3GPP TS 45.005: "Radio transmission and reception".
[5] 3GPP TS 45.010: "Radio subsystem synchronization".
[6] 3GPP TS 44.060: "Radio Link Control/ Medium Access Control (RLC/MAC) protocol".
[7] 3GPP TS 43.064: "General Packet Radio Service (GPRS)".
[8] 3GPP TS 45.003: "Channel Coding".
1.2 Abbreviations
Abbreviations used in this specification are listed in 3GPP TR 21.905. In addition to abbreviations in 3GPP TR 21.905
the following abbreviation apply:
AQPSK Adaptive Quadrature Phase Shift Keying
EC Extended Coverage
ESAB Extended Synchronization Access Burst
2 Modulation format for GMSK
2.1 Modulating symbol rate
The modulating symbol rate is the normal symbol rate which is defined as 1/T = 1 625/6 ksymb/s (i.e. approximately
270.833 ksymb/s), which corresponds to 1 625/6 kbit/s (i.e. 270.833 kbit/s). T is the normal symbol period (see
3GPP TS 45.010).
ETSI
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3GPP TS 45.004 version 15.0.0 Release 15 6 ETSI TS 145 004 V15.0.0 (2018-07)
2.2 Start and stop of the burst
Before the first bit of the bursts as defined in 3GPP TS 45.002 enters the modulator, the modulator has an internal state
as if a modulating bit stream consisting of consecutive ones (d = 1) had entered the differential encoder. Also after the
i
last bit of the time slot, the modulator has an internal state as if a modulating bit stream consisting of consecutive ones
(d = 1) had continued to enter the differential encoder. These bits are called dummy bits and define the start and the
i
stop of the active and the useful part of the burst as illustrated in figure 1. Nothing is specified about the actual phase of
the modulator output signal outside the useful part of the burst. In case of EC operation, the phase during the useful part
of contiguous bursts, belonging to the same blind physical layer transmissions within a TDMA frame, has a fixed
relation, see subclauses 2.6 and 2.7.
dummy bits 3 tail bits 3 tail bits dummy bits
.......111111 000....... .......000 111111.......
Output phase
The useful part
1/2 bit 1/2 bit
The active part
Figure 1: Relation between active part of burst, tail bits and dummy bits. For the normal burst the
useful part lasts for 147 modulating bits
2.3 Differential encoding
Each data value d = [0,1] is differentially encoded. The output of the differential encoder is:
i
$
dd=⊕d ({d∈ 01,})
ii i−1 i
where ⊕ denotes modulo 2 addition.
The modulating data value α input to the modulator is:
i
$
αα=−12d ({∈ −1,+1})
ii i
2.4 Filtering
The modulating data values α as represented by Dirac pulses excite a linear filter with impulse response defined by:
i
t
g()t = h()t * rect
T
where the function rect(x) is defined by:
t 1 T
rect=
TT 2
ETSI
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3GPP TS 45.004 version 15.0.0 Release 15 7 ETSI TS 145 004 V15.0.0 (2018-07)
t
rect = 0 otherwise
T
and * means convolution. h(t) is defined by:
2
− t
exp
22
2δ T
ht() =
()2πδ. T
ln(2)
where δ==and BT 03.
2πBT
where B is the 3 dB bandwidth of the filter with impulse response h(t). This theoretical filter is associated with
tolerances defined in 3GPP TS 45.005.
2.5 Output phase
The phase of the modulated signal is:
ti'−T
ϕα('th) = π g(u)du
i
i
−∞
where the modulating index h is 1/2 (maximum phase change in radians is π/2 per data interval).
The time reference t' = 0 is the start of the active part of the burst as shown in figure 1. This is also the start of the bit
period of bit number 0 (the first tail bit) as defined in 3GPP TS 45.002.
2.6 Modulation
The modulated RF carrier, except for start and stop of the TDMA burst or ESAB (see 3GPP TS 45.002 [3]) may
therefore be expressed as:
2E
c
xt(')=+. cos(2πϕft' ('t )+ϕ )
00
T
where E is the energy per modulating bit, f is the centre frequency and ϕ is a random phase and is constant during
c 0 0
one burst or ESAB (see 3GPP TS 45.002 [3]).
In case of EC operation when using blind physical layer transmissions (see 3GPP TS 43.064 [7]) the modulated RF
carrier, except for start and stop of the burst may, for each blind physical layer transmission of a burst for which phase
and amplitude coherency is required (see 3GPP TS 45.005 [4]), be expressed as:
2E
c
x(t') = . cos(2π f (t'+t ) +ϕ(t') +ϕ +ϕ )
0 0 157 0
T
where
- t is a burst-specific time offset, constant during one burst, and is defined as the time difference between time
0
instant t' = 0 for the current burst and t' = 0 for the first transmission of the same burst in the current TDMA
frame.
ϕ πh, and is constant during one burst.
- is a phase shift of either 0 or
157
ETSI
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3GPP TS 45.004 version 15.0.0 Release 15 8 ETSI TS 145 004 V15.0.0 (2018-07)
- ϕ is a random phase and is constant during all blind physical layer transmissions of the same burst within the
0
same TDMA frame.
For EC-GSM_IoT, only integer timeslot lengths are allowed (see 3GPP TS 45.010 [5]). If any blind physical layer
transmission is trans
...