ETSI TS 101 851-3-1 V2.1.1 (2008-01)

Satellite Earth Stations and Systems (SES); Satellite Component of UMTS/IMT-2000; Part 3: Spreading and modulation; Sub-part 1: G-family (S-UMTS-G 25.213)

RTS/SES-00298-3-1

General Information

• Status: Published
• Publication Date: 30-Jan-2008
• Technical Committee: SES MSS - SES WG on Mobile Satellite Systems
• Current Stage: 12 - Completion
• Due Date: 08-Jan-2008
• Completion Date: 31-Jan-2008

Standards Content (Sample)

ETSI TS 101 851-3-1 V2.1.1 (2008-01)
Technical Specification


Satellite Earth Stations and Systems (SES);
Satellite Component of UMTS/IMT-2000;
Part 3: Spreading and modulation;
Sub-part 1: G-family (S-UMTS-G 25.213)

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2 ETSI TS 101 851-3-1 V2.1.1 (2008-01)



Reference
RTS/SES-00298-3-1
Keywords
interface, MES, MSS, radio, satellite, UMTS
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ETSI

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3 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
Contents
Intellectual Property Rights.4
Foreword.4
Introduction .4
1 Scope.6
2 References.6
2.1 Normative references.6
3 Symbols and abbreviations.7
3.1 Symbols.7
3.2 Abbreviations.7
4 Uplink spreading and modulation .7
4.1 Overview.7
4.2 Spreading.8
4.2.1 DPCCH/DPDCH.8
4.2.2 PRACH.9
4.2.2.1 PRACH preamble part .9
4.2.2.2 PRACH message part.9
4.3 Code generation and allocation .10
4.3.1 Channelization codes.10
4.3.1.1 Code definition.10
4.3.1.2 Code allocation for DPCCH/DPDCH .11
4.3.1.3 Code allocation for PRACH message part .11
4.3.2 Scrambling codes.11
4.3.2.1 General.11
4.3.2.2 Long scrambling sequence.11
4.3.2.3 Short scrambling sequence.13
4.3.2.4 DPCCH/DPDCH scrambling code.14
4.3.2.5 PRACH message part scrambling code.14
4.3.3 PRACH preamble codes .15
4.3.3.1 Preamble code construction .15
4.3.3.2 Preamble scrambling code .15
4.3.3.3 Preamble signature.15
4.4 Modulation.16
4.4.1 Modulating chip rate.16
4.4.2 Modulation.16
5 Downlink spreading and modulation .17
5.1 Spreading.17
5.2 Code generation and allocation .18
5.2.1 Channelization codes.18
5.2.2 Scrambling code.18
5.2.3 Synchronization codes.20
5.2.3.1 Code generation.20
5.2.3.2 Code allocation of SSC .21
5.3 Modulation.22
5.3.1 Modulating chip rate.22
5.3.2 Modulation.22
Annex A (informative): Generalized Hierarchical Golay Sequences.23
A.1 Alternative generation .23
History .24

ETSI

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4 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document 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 (http://webapp.etsi.org/IPR/home.asp).
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.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Satellite Earth Stations and
Systems (SES).
The present document is specifying the Satellite Radio Interface referenced as SRI Family G at ITU-R, in the frame of
the modification of ITU-R Recommendation M.1457 [4]. This modification has been approved at SG8 meeting in
November 2005.
The present document is part 3, sub-part 1 of a multi-part deliverable covering Satellite Earth Stations and Systems
(SES); Satellite Component of UMTS/IMT-2000; G-family, as identified below:
Part 1: "Physical channels and mapping of transport channels into physical channels";
Part 2: "Multiplexing and channel coding";
Part 3: "Spreading and modulation";
Sub-part 1: "G-family (S-UMTS-G 25.213)";
Sub-part 2: "A-family (S-UMTS-A 25.213)";
Part 4: "Physical layer procedures";
Part 5: "UE Radio Transmission and Reception";
Part 6: "Ground stations and space segment radio transmission and reception".
Introduction
S-UMTS stands for the Satellite component of the Universal Mobile Telecommunication System. S-UMTS systems will
complement the terrestrial UMTS (T-UMTS) and inter-work with other IMT-2000 family members through the UMTS
rd
core network. S-UMTS will be used to deliver 3 generation Mobile Satellite Services (MSS) utilizing either low
(LEO) or medium (MEO) earth orbiting, or geostationary (GEO) satellite(s). S-UMTS systems are based on terrestrial
3GPP specifications and will support access to GSM/UMTS core networks.
NOTE 1: The term T-UMTS will be used in the present document to further differentiate the Terrestrial UMTS
component.
Due to the differences between terrestrial and satellite channel characteristics, some modifications to the terrestrial
UMTS (T-UMTS) standards are necessary. Some specifications are directly applicable, whereas others are applicable
with modifications. Similarly, some T-UMTS specifications do not apply, whilst some S-UMTS specifications have no
corresponding T-UMTS specification.
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5 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
Since S-UMTS is derived from T-UMTS, the organization of the S-UMTS specifications closely follows the original
rd
3 Generation Partnership Project (3GPP) structure. The S-UMTS numbers have been designed to correspond to the
3GPP terrestrial UMTS numbering system. All S-UMTS specifications are allocated a unique S-UMTS number as
follows:
S-UMTS-n xx.yyy
Where:
• The numbers xx and yyy correspond to the 3GPP numbering scheme.
• n (n = A, B, C, etc.) denotes the family of S-UMTS specifications.
An S-UMTS system is defined by the combination of a family of S-UMTS specifications and 3GPP specifications, as
follows:
• If an S-UMTS specification exists it takes precedence over the corresponding 3GPP specification (if any). This
precedence rule applies to any references in the corresponding 3GPP specifications.
NOTE 2: Any references to 3GPP specifications within the S-UMTS specifications are not subject to this
precedence rule.
EXAMPLE: An S-UMTS specification may contain specific references to the corresponding 3GPP
specification.
• If an S-UMTS specification does not exist, the corresponding 3GPP specification may or may not apply. The
exact applicability of the complete list of 3GPP specifications shall be defined at a later stage.
ETSI

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6 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
1 Scope
The present document describes spreading and modulation for the Physical Layer for family G of the satellite
component of UMTS (S-UMTS-G).
It is based on the FDD mode of UTRA defined by TS 101 851-1-1 [1], TS 101 851-2-1 [2], TS 101 851-4-1 [3] and
adapted for operation over satellite transponders.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
For online referenced documents, information sufficient to identify and locate the source shall be provided. Preferably,
the primary source of the referenced document should be cited, in order to ensure traceability. Furthermore, the
reference should, as far as possible, remain valid for the expected life of the document. The reference shall include the
method of access to the referenced document and the full network address, with the same punctuation and use of upper
case and lower case letters.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
[1] ETSI TS 101 851-1-1: "Satellite Earth Stations and Systems (SES); Satellite Component of
UMTS/IMT-2000; Part 1: Physical channels and mapping of transport channels into physical
channels; Sub-part 1: G-family (S-UMTS-G 25.211)".
[2] ETSI TS 101 851-2-1: "Satellite Earth Stations and Systems (SES); Satellite Component of
UMTS/IMT-2000; Part 2: Multiplexing and channel coding; Sub-part 1: G-family
(S-UMTS-G 25.212)".
[3] ETSI TS 101 851-4-1: "Satellite Earth Stations and Systems (SES); Satellite Component of
UMTS/IMT-2000; Part 4: Physical layer procedures; Sub-part 1: G-family (S-UMTS-G 25.214)".
[4] ITU-R Recommendation M.1457 (2006): "Detailed specifications of the radio interfaces of
International Mobile Telecommunications-2000 (IMT-2000)".
ETSI

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7 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
3 Symbols and abbreviations
3.1 Symbols
For the purposes of the present document, the following symbols apply:
C n:th channelization code with spreading factor SF
ch,SF,n
C PRACH preamble code for n:th preamble scrambling code and signature s
pre,n,s
C PRACH/PCPCH signature code for signature s
sig,s
S n:th DPCCH/DPDCH uplink scrambling code
dpch,n
S n:th PRACH preamble scrambling code
r-pre,n
S n:th PRACH message scrambling code
r-msg,n
S DL scrambling code
dl,n
C PSC code
psc
C n:th SSC code
ssc,n
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AICH Acquisition Indicator CHannel
CCPCH Common Control Physical CHannel
CPICH Common PIlot CHannel
DCH Dedicated CHannel
DPCCH Dedicated Physical Control CHannel
DPCH Dedicated Physical CHannel
DPDCH Dedicated Physical Data CHannel
DTX Discontinuous Transmission
FDD Frequency Division Duplex
GEO Geostationary Earth Orbit
LEO Low Earth Orbit
Mcps Mega chip per second
MEO Medium Earth Orbit
MICH MBMS Indication CHannel
MSS Mobile Satellite Services
OVSF Orthogonal Variable Spreading Factor (codes)
PICH Page Indication CHannel
PRACH Physical Random Access CHannel
PSC Primary Synchronization Code
QPSK Quaternary Phase Shift Keying
SCH Synchronization CHannel
SF Spreading Factor
SSC Secondary Synchronization Code
USRAN UMTS Satellite Radio Access Network
UTRA UMTS Terrestrial Radio Access
4 Uplink spreading and modulation
4.1 Overview
Spreading is applied to the physical channels. It consists of two operations. The first is the channelization operation,
which transforms every data symbol into a number of chips, thus increasing the bandwidth of the signal. The number of
chips per data symbol is called the Spreading Factor (SF). The second operation is the scrambling operation, where a
scrambling code is applied to the spread signal.
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8 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
With the channelization, data symbols on so-called I- and Q-branches are independently multiplied with an OVSF code.
With the scrambling operation, the resultant signals on the I- and Q-branches are further multiplied by complex-valued
scrambling code, where I and Q denote real and imaginary parts, respectively.
4.2 Spreading
4.2.1 DPCCH/DPDCH
Figure 1 illustrates the principle of the uplink spreading of DPCCH and DPDCHs. The binary DPCCH and DPDCHs to
be spread are represented by real-valued sequences, i.e. the binary value "0" is mapped to the real value +1, and the
binary value "1" is mapped to the real value -1. The DPCCH is spread to the chip rate by the channelization code c .
c
The n:th DPDCH called DPDCH is spread to the chip rate by the channelization code c . One DPCCH, up to six
n d,n
parallel DPDCHs, i.e. 1 ≤ n ≤ 6.
c β
d,1
d
DPDCH
1
c
β
d,3
d
I
DPDCH
3
S
dpch,n
Σ
c
β
d,5 d
I+jQ
DPDCH
5
S
c
β
d,2
d
DPDCH
2
c
β
d,4 d
DPDCH
4
Q
c β
d,6
d
Σ
DPDCH
6
j
c
β
c
c
DPCCH

Figure 1: Spreading for uplink DPCCH and DPDCHs
After channelization, the real-valued spread signals are weighted by gain factors, β for DPCCH, and β for all
c d
DPDCHs.
The β and β values are signalled by higher layers or calculated as described in TS 101 851-4-1 [3]. At every instant in
c d
time, at least one of the values β and β has the amplitude 1,0. The β and β values are quantized into 4 bit words. The
c d c d
quantization steps are given in table 1.
ETSI

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9 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
Table 1: The quantization of the gain parameters
Signalling values for Quantized amplitude ratios
β and β β and β
c d c d
15 1,0
14 14/15
13 13/15
12 12/15
11 11/15
10 10/15
9 9/15
8 8/15
7 7/15
6 6/15
5 5/15
4 4/15
3 3/15
2 2/15
1 1/15
0 Switch off

After the weighting, the stream of real-valued chips on the I- and Q-branches are then summed and treated as a
complex-valued stream of chips. This complex-valued signal is then scrambled by the complex-valued scrambling code

S . The scrambling code is applied aligned with the radio frames, i.e. the first scrambling chip corresponds to the
dpch,n
beginning of a radio frame.
4.2.2 PRACH
4.2.2.1 PRACH preamble part
The PRACH preamble part consists of a complex-valued code, described in clause 4.3.3.
4.2.2.2 PRACH message part
Figure 2 illustrates the principle of the spreading and scrambling of the PRACH message part, consisting of data and
control parts. The binary control and data parts to be spread are represented by real-valued sequences, i.e. the binary
value "0" is mapped to the real value +1, while the binary value "1" is mapped to the real value -1. The control part is
spread to the chip rate by the channelization code c , while the data part is spread to the chip rate by the channelization
c
code c .
d
c β
d
d
S
r-msg,n
PRACH message
I
data part
I+jQ
PRACH message
Q
S
control part
c j
β
c
c

Figure 2: Spreading of PRACH message part
After channelization, the real-valued spread signals are weighted by gain factors, β for the control part and β for the
c d
data part. At every instant in time, at least one of the values β and β has the amplitude 1,0. The β-values are quantized
c d
into 4 bit words. The quantization steps are given in clause 4.2.1.
ETSI

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10 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
After the weighting, the stream of real-valued chips on the I- and Q-branches is treated as a complex-valued stream of
chips. This complex-valued signal is then scrambled by the complex-valued scrambling code S . The 10 ms
r-msg,n
scrambling code is applied aligned with the 10 ms message part radio frames, i.e. the first scrambling chip corresponds
to the beginning of a message part radio frame.
4.3 Code generation and allocation
4.3.1 Channelization codes
4.3.1.1 Code definition
The channelization codes of figure 1 are Orthogonal Variable Spreading Factor (OVSF) codes that preserve the
orthogonality between a user's different physical channels. The OVSF codes can be defined using the code tree of
figure 3.
C =(1,1,1,1)
ch,4,0
C = (1,1)
ch,2,0
C = (1,1,-1,-1)
ch,4,1
C = (1)
ch,1,0
C = (1,-1,1,-1)
ch,4,2
C = (1,-1)
ch,2,1
C = (1,-1,-1,1)
ch,4,3
SF = 1 SF = 2 SF = 4

Figure 3: Code-tree for generation of Orthogonal Variable Spreading Factor (OVSF) codes
In figure 3, the channelization codes are uniquely described as C , where SF is the spreading factor of the code and
ch,SF,k
k is the code number, 0 ≤ k ≤ SF- 1.
Each level in the code tree defines channelization codes of length SF, corresponding to a spreading factor of SF in
figure 3.
The generation method for the channelization code is defined as:
C = 1,
ch,1,0
⎡C ⎤ C C
⎡ ⎤ 1 1
⎡ ⎤
ch,2,0 ch,1,0 ch,1,0
= =
⎢ ⎥
⎢ ⎥ ⎢ ⎥
C − C
C 1 −1
ch,1,0 ch,1,0
ch,2,1 ⎣ ⎦
⎣ ⎦ ⎣ ⎦
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11 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
C ⎡ C C ⎤
⎡ ()n+1 ⎤ n n
ch, 2 ,0 ch, 2 ,0 ch, 2 ,0
⎢ ⎥ ⎢ ⎥
C C − C
()n+1 n n
ch, 2 ,1 ch, 2 ,0 ch,2 ,0
⎢ ⎥
⎢ ⎥
⎢ ⎥ ⎢ C C ⎥
C
()n+1 n n
ch, 2 ,2 ch,2 ,1 ch,2 ,1
⎢ ⎥
⎢ ⎥
C − C
C
()n+1 = n n
ch,2 ,3 ch,2 ,1 ch, 2 ,1
⎢ ⎥ ⎢ ⎥
⎢ ⎥
⎢ ⎥
: :
:
⎢ ⎥ ⎢ ⎥
C C
C
()n+1 (n+1) n n n n
⎢ ⎥
⎢ ch, 2 ,2 −2 ⎥ ch, 2 , 2 −1 ch, 2 ,2 −1
⎢ ⎥ ⎢ ⎥
C − C
C
()n+1 ()n+1 n n n n
ch, 2 ,2 −1 ch, 2 , 2 −1 ch,2 , 2 −1
⎣ ⎦ ⎣ ⎦
The leftmost value in each channelization code word corresponds to the chip transmitted first in time.
4.3.1.2 Code allocation for DPCCH/DPDCH
For the DPCCH and DPDCHs the following applies:
- The DPCCH is always spread by code c = C .
c ch,256,0
- When only one DPDCH is to be transmitted, DPDCH is spread by code c = C where SF is the
1 d,1 ch,SF,k
spreading factor of DPDCH and k = SF / 4.
1
- When more than one DPDCH is to be transmitted, all DPDCHs have spreading factors equal to 4. DPDCH is
n
spread by the code c = C , where k = 1 if n ∈ {1, 2}, k = 3 if n ∈ {3, 4}, and k = 2 if n ∈ {5, 6}.
d,n ch,4,k
If a power control preamble is used to initialize a DCH, the channelization code for the DPCCH during the power
control preamble shall be the same as that to be used afterwards.
4.3.1.3 Code allocation for PRACH message part
The preamble signature s, 0 ≤ s ≤ 15, points to one of the 16 nodes in the code-tree that corresponds to channelization
codes of length 16. The sub-tree below the specified node is used for spreading of the message part. The control part is
spread with the channelization code c (as shown in clause 4.2.2.2) of spreading factor 256 in the lowest branch of the
c
sub-tree, i.e. c = C where m = 16 × s + 15. The data part uses any of the channelization codes from spreading
c ch,256,m
factor 32 to 256 in the upper-most branch of the sub-tree. To be exact, the data part is spread by channelization code
c = C and SF is the spreading factor used for the data part and m = SF × s / 16.
d ch,SF,m
4.3.2 Scrambling codes
4.3.2.1 General
All uplink physical channels are subjected to scrambling with a complex-valued scrambling code. The DPCCH/DPDCH
may be scrambled by either long or short scrambling codes, defined in clause 4.3.2.4. The PRACH message part is
scrambled with a long scrambling code, defined in clause 4.3.2.5.
24 24
There are 2 long and 2 short uplink scrambling codes. Uplink scrambling codes are assigned by higher layers.
The long scrambling code is built from constituent long sequences defined in clause 4.3.2.2, while the constituent short
sequences used to build the short scrambling code are defined in clause 4.3.2.3.
4.3.2.2 Long scrambling sequence
The long scrambling sequences c and c are constructed from position wise modulo 2 sum of 38 400 chips
long,1,n long,2,n
segments of two binary m-sequences generated by means of two generator polynomials of degree 25. Let x, and y be the
25 3
two m-sequences respectively. The x sequence is constructed using the primitive (over GF(2)) polynomial X + X + 1.
25 3 2
The y sequence is constructed using the polynomial X + X + X + X + 1. The resulting sequences thus constitute
segments of a set of Gold sequences.
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12 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
The sequence c is a 16 777 232 chips shifted version of the sequence c .
long,2,n long,1,n
Let n … n be the 24 bit binary representation of the scrambling sequence number n with n being the least significant
23 0 0
bit. The x sequence depends on the chosen scrambling sequence number n and is denoted x , in the sequel. Furthermore,
n
let x (i) and y(i) denote the i:th symbol of the sequence x and y, respectively.
n n
The m-sequences x and y are constructed as:
n
Initial conditions:
- x (0) = n , x (1) = n , … = x (22) = n ,x (23) = n , x (24) = 1.
n 0 n 1 n 22 n 23 n
- y(0) = y(1) = … = y(23) = y(24) = 1.
Recursive definition of subsequent symbols:
25
- x (i + 25) = x (i + 3) + x (i) modulo 2, i = 0,…, 2 - 27.
n n n
25
- y(i + 25) = y(i + 3) + y(i + 2) + y(i + 1) + y(i) modulo 2, i = 0,…, 2 - 27.
Define the binary Gold sequence z by:
n
25
- z (i) = x (i) + y(i) modulo 2, i = 0, 1, 2, …, 2 - 2.
n n
The real valued Gold sequence Z is defined by:
n
+1 if z (i) = 0
⎧
n
25
Z (i) = for i = 0,1,K,2 − 2.
⎨
n
−1 if z (i) = 1
⎩ n
Now, the real-valued long scrambling sequences c and c are defined as follows:
long,1,n long,2,n
25
c (i) = Z (i), i = 0, 1, 2, …, 2 - 2; and
long,1,n n
25 25
c (i) = Z ((i + 16 777 232) modulo (2 - 1)), i = 0, 1, 2, …, 2 - 2.
long,2,n n
Finally, the complex-valued long scrambling sequence C , is defined as:
long, n
i
C (i) = c (i)(1+ j()−1 c ()2 i / 2 )
⎣⎦
long ,n long,1,n long,2,n
25
where i = 0, 1, …, 2 - 2 and ⎣⎦ denotes rounding to nearest lower integer.
c
long,1,n
LSB
MSB
c
long,2,n

Figure 4: Configuration of uplink scrambling sequence generator
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13 ETSI TS 101 851-3-1 V2.1.1 (2008-01)
4.3.2.3 Short scrambling sequence
The short scrambling sequences c (i) and c (i) are defined from a sequence from the family of periodically
short,1,n short,2,n
extended S(2) codes.
Let n n …n be the 24 bit binary representation of the code number n.
23 22 0
The n:th quaternary S(2) sequence z (i), 0 ≤ n ≤ 16 777 215, is obtained by modulo 4 addition of three sequences, a
n
quaternary sequence a(i) and two binary sequences b(i) and d(i), where the initial loading of the three sequences is
determined from the code number n. The sequence z (i) of length 255 is generated according to the following relation:
n
- z (i) = a(i) + 2b(i) + 2d(i) modulo 4, i = 0, 1, …, 254;
n
where the quaternary sequence a(i) is generated recursively by the polynomial
8 5 3 2
g (x) = x + x + 3x + x + 2x + 1 as:
0
- a(0) = 2n + 1 modulo 4;
0
- a(i) = 2n modulo 4, i = 1, 2, …, 7;
i
- a(i) = 3a(i - 3) + a(i - 5) + 3a(i - 6) + 2a(i - 7) + 3a(i - 8) modulo 4, i
...