ETSI TS 144 035 V13.0.0 (2016-01)

Digital cellular telecommunications system (Phase 2+); Location Services (LCS); Broadcast network assistance for Enhanced Observed Time Difference (E-OTD) and Global Positioning System (GPS) positioning methods (3GPP TS 44.035 version 13.0.0 Release 13)

RTS/TSGG-0244035vd00

General Information

• Status: Published
• Publication Date: 24-Jan-2016
• Technical Committee: 3GPP GERAN 2 - Protocol aspects
• Current Stage: 12 - Completion
• Due Date: 20-Jan-2016
• Completion Date: 25-Jan-2016

Standards Content (Sample)

ETSI TS 1144 035 V13.0.0 (201616-01)






TECHNICAL SPECIFICATIONION
Digital cellular telecocommunications system (Phahase 2+);
Locatcation Services (LCS);
Broadcast network assssistance for Enhanced Obseserved Time
Difference (E-OTD) an and Global Positioning Systetem (GPS)
posositioning methods
(3GPP TS 44.0.035 version 13.0.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS

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3GPP TS 44.035 version 13.0.0 Release 13 1 ETSI TS 144 035 V13.0.0 (2016-01)



Reference
RTS/TSGG-0244035vd00
Keywords
GSM
ETSI
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ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 2 ETSI TS 144 035 V13.0.0 (2016-01)
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 (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.
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
http://webapp.etsi.org/key/queryform.asp.
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 44.035 version 13.0.0 Release 13 3 ETSI TS 144 035 V13.0.0 (2016-01)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 4
1 Scope . 5
2 References . 5
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 6
4 Broadcast Message Contents . 6
4.1 E-OTD Assistance Data Broadcast Message . 6
4.1.1 E-OTD Assistance Data Broadcast Message Content. 7
4.1.1.1 Message Structure Definition IE . 8
4.1.1.2 Reference Time IE . 11
4.1.1.3 Ciphering Serial Number IE . 11
4.1.1.4 Time Slot Scheme IE . 11
4.1.1.5 Neighbour Bitmap Definition IE . 12
4.1.1.6 Sectored Channels Definition IE . 12
4.1.1.7 Sectored Channels BTS ID Definition IE . 12
4.1.1.8 Sectored BTS Sync/Async Definition IE . 13
4.1.1.9 Multiframe Offset Values IE . 13
4.1.1.10 BCC Definition IE . 13
4.1.1.11 RTD Drift Factor Values IE . 14
4.1.1.12 Channel RTD Values IE . 15
4.1.1.13 Serving Cell Location IE . 16
4.1.1.14 Relative Neighbour Location IE . 16
4.2 GPS Assistance Data Broadcast Message . 18
4.2.1 GPS Assistance Data Content . 18
4.2.1.1 DGPS Correction Data . 19
4.2.1.1.1 GSM Time Present IE . 20
4.2.1.1.2 BTS Clock Drift Present IE . 20
4.2.1.1.3 BTS Clock Drift IE . 20
4.2.1.1.4 Reference Location IE . 20
4.2.1.1.5 Reference Time IE . 20
4.2.1.1.6 Status/Health IE . 21
4.2.1.1.7 N_SAT IE . 21
4.2.1.1.8 DGPS Corrections IE . 21
4.2.1.2 Ephemeris and Clock Correction Data . 22
4.2.1.3 Almanac and Other Data . 24
Annex A (informative): Overview of Broadcast Assistance for E-OTD and GPS . 26
A.1 General . 26
A.2 E-OTD Assistance Broadcast . 26
A.3 GPS Assistance Broadcast . 27
A.4 Impact on Other Services . 28
Annex B (informative): Example of E-OTD Assistance Data Broadcast Message . 29
Annex C (informative): Example of GPS Assistance Data Broadcast Message . 33
Annex D (informative): Change History . 34
History . 35
ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 4 ETSI TS 144 035 V13.0.0 (2016-01)
Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The present document defines the contents of LCS assistance data broadcast messages from the Serving Mobile
Location Centre (SMLC) and the Mobile Station (MS).
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 44.035 version 13.0.0 Release 13 5 ETSI TS 144 035 V13.0.0 (2016-01)
1 Scope
The present document contains the content of messages necessary for support of MS Based location service operation
on the mobile radio interface layer 3.
2 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] Void.
[3] Void.
[4] Void.
[5] Void"
[6] 3GPP TS 23.041: "Technical realization of Cell Broadcast Service (CBS)".
[7] Void.
[8] Void.
[9] Void.
[10] Void.
[11] Void.
[12] Void.
[13] Void.
[14] Void.
[15] RTCM-SC104: "RTCM Recommended Standards for Differential GNSS Service (v.2.2)".
[16] ICD-GPS-200: "Navstar GPS Space Segment / Navigation User Interfaces".
ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 6 ETSI TS 144 035 V13.0.0 (2016-01)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
E-OTD Assistance Data Message: contains the RTD and BTS coordinates of the neighbours that should be used in
E-OTD measurements. This E-OTD Assistance Data is broadcasted using CBCH channel using SMSCB DRX service.
The reception of this broadcast message enables MS to calculate its own location.
GPS Assistance Data Message: contains GPS differential corrections. The reception of this broadcast message enables
MS to have calculate more accurate location estimate.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 apply.
4 Broadcast Message Contents
This clause describes the LCS Assistance Data messages to be broadcasted in SMSCB message's content part over
CBCH channel using SMSCB DRX service. The rules and contets are described so that SMLC is able to construct the
message as well as MS is able to process the received message. The E-OTD Assistance Data message contains RTD
and BTS coordinate information and GPS Assistance Data contains GPS Differential Correction data, Emphemeris and
Clock Correction Data and Almanac and Other Data.
4.1 E-OTD Assistance Data Broadcast Message
The E-OTD Assistance Data message contents are defined in this clause. The E-OTD Assistance Data message is built
so that it has always a fixed length and some of the information elements are scalable according to the amount of
neighbours and the amount of sectored channels. The information elements are in the order which is described in
subclause 4.1.1 and no spare bits are allowed between elements. The MSB bits of the information elements are
presented always first and if boundary of the octet divides the information element then the LSB part of the information
element continues in the LSB part of the next octet (figure 1). Example of E-OTD Assistance Data Broadcast Message
is in annex B. The channel to broadcast the E-OTD Assistance Data message is CBCH over which the SMSCB DRX
service is used. One SMSCB message has fixed information data length of 82 octets and the purpose is always to use
the whole fixed length message capacity for the message. MS can identify the LCS SMSCB message with E-OTD
Message Identifier declared in 3GPP TS 23.041.
ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 7 ETSI TS 144 035 V13.0.0 (2016-01)
MSB LSB
Information Element Containing 26 bits
7   6   5   4   3   2   1   0 7   6   5   4   3   2   1   0 7   6   5   4   3   2   1   0 1   0
Broadcast Message
7   6   5   4   3   2   1   0
Octet n
7   6   5   4   3   2   1   0
Octet n+1
7   6   5   4   3   2   1   0
Octet n+2
MSB   Next IE 1   0
Octet n+3
  …………. Next IE LSB
Octet n+4
  ………….
Octet n+5

Figure 1: Information element bit mapping to the broadcast message
4.1.1 E-OTD Assistance Data Broadcast Message Content
The Broadcast Assistance Data is a point-to-multipoint message from the GSM Network to the MSs. This message
gives assistance data to the MS for performing E-OTD measurements and calculating its own position. It contains the
following information elements. The information elements are always in the order described in table 1. The ciphered
part of message is end of message and indicated with grey shading in table 1.
Table 1: E-OTD Assistance Data Broadcast Message Content
Information element Type/Reference Presence
Message Structure Definition Message Structure M
Definition 4.1.1.1
Reference Time Reference Time 4.1.1.2 M
Ciphering Serial Number Ciphering Serial C
Number 4.1.1.3
Time Slot Scheme Time Slot M
Scheme 4.1.1.4
Neighbour Bitmap Definition Neighbour C
BitmapDefinition 4.1.1.5
Sectored Channels Definition Sectored Channels C
Definition 4.1.1.6
Sectored Channels BTS ID Sectored Channel's BTS C
Definition ID Definition 4.1.1.7
Sectored BTS Sync/Async Sectored BTS C
Definition Sync/Async
Definition 4.1.1.8
51 Multiframe Offset Values 51 Multiframe Offset M
Values 4.1.1.9
BCC Definition BCC Definition 4.1.1.10 M
RTD Drift Factor Values RTD Drift Factor C
Values 4.1.1.11
Channel RTD Values Channel RTD C
Values 4.1.1.12
Serving Cell Location Serving Cell M
Location 4.1.1.13
Relative Neighbour Location Values Relative Neighbour M
Location Values 4.1.1.14

ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 8 ETSI TS 144 035 V13.0.0 (2016-01)
4.1.1.1 Message Structure Definition IE
This IE contains the definition of this broadcast message. The length of this IE is 19 bits and it is mandatory. This IE
contains the following bits.
Table 2: Message Structure Definition
Bit order
Bit
Definition
in field
1 LSB
2 Neighbour List Map (bits 2-0)
MSB
3
4 LSB
5
Accuracy Range (bits 2-0)

6
MSB
7 Ciphering Key Flag
8 Cipher On/Off
9 Sector Ind
10 RTD Range
11 LSB
RTD Accuracy (bits 1-0)
12
MSB
13 RTD Drift Factors Present
14 RTDs Present
15 LSB

16

17
Number of Neighbours (bits 4-0)
18


19
MSB

The first three octets upto bit 3 in octet 3 in the broadcast message's content part containing the Message Structure
Definition IE look always as follows.
8 7 6 5 4 3 2 1
Cipher Cipher- Accuracy Range Neighbour List Map Octet1
On/Off ing Key (bits 2-0) (bits 2-0)
Flag
Number of RTDs RTD RTD Accuracy RTD Sector Octet2
Neighbours Present Drift (bits 1-0) Range Ind
(bits 4-3) Factors
Present
(Next IE) Number of Neighbours (bits 2-0) Octet3

The definitions of each structure item is declared below:
Neighbour List Map
These bits define in which order the neighbours in the System Information Neighbour List (max 32 neighbours) are
reported with the broadcast message.
- The Neighbour List Map will also affect the amount of bits that can be used for Relative Neighbour Location
Value definitions.
- This Broadcast Assistance Data message is always referring to the neighbour BTSs included in the System
Information Neighbour List which is received in idle state from BCCH. The E-OTD broadcast message does not
allow the possibility for delivering assistance data for other BTSs (outside the the System Information Neighbour
List.
ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 9 ETSI TS 144 035 V13.0.0 (2016-01)
Table 3: Neighbour List Map
2 1 0 Definition
0 0 0 All Neigbours from neighbour list
0 0 1 Even Neighbours from neighbour list
0 1 0 Odd Neighbours from neighbour list
st st
0 1 1 1 & 1 +n*3
nd nd
1 0 0 2 & 2 +n*3
rd rd
1 0 1 3 & 3 +n*3
1 1 0 Neighbour Bitmap Definition
1 1 1 Spare

- All Neighbours means all the neighbours from System Information Neighbour list (max 32 neighbours) are
reported in this broadcast message (1 broadcast message).
- Even/Odd neighbours from neighbour list means the even/odd list entries in the System Information Neighbour
List are reported in this broadcast message (two broadcast messages needed).
st st st th th th st
& 1 + n*3 means that 1 , 4 , 7 , 10 , …, 31 (max 11 neighbours) will be reported in this broadcast message
- 1
(1/3 of total broadcast).
nd nd nd th th th nd
- 2 & 2 +n*3 means that 2 , 5 , 8 , 11 , …, 32 (max 11 neighbours) will be reported in this broadcast
message (2/3 of total broadcast).
rd rd rd th th th th
- 3 & 3 +n*3 means that 3 , 6 , 9 , 12 , …, 30 (max 10 neighbours) will be reported in this broadcast
message (3/3 of total broadcast).
st st nd nd rd rd
& 1 +n*3, 2 & 2 +n*3 and 3 & 3 +n*3 means total 3 broadcast messages.
- The 1
- Neighbour Bitmap Definition will define which neighbours are included into this broadcast message, see
subclause 4.1.1.5.
Accuracy Range
The accuracy range declares the accuracy of the values in the Relative Neigbour Location Value IE. The accuracy range
has the following information.
Table 4: Accuracy Range
2 1 0 Definition
0 0 0 5 km
0 0 1 10 km
0 1 0 15 km
0 1 1 20 km
1 0 0 30 km
1 0 1 45 km
1 1 0 60 km
1 1 1 120 km

For example if there are 15 bits (1 sign bit and 14 value bits) reserved for Relative Neighbour North or East Value and
the accuracy range is defined to be 20 km, then resolution of Relative Neighbour North or East Value is 0.6 m.
Ciphering Key Flag
The MS gets two (2) deciphering keys always with location update, a deciphering key that is time stamped to be current
one and deciphering key that time stamped to be next one. Thus the MS has always two deciphering keys in memory.
With this Ciphering Key Flag in this broadcast message the MS knows whether to use current/next deciphering key for
deciphering the received broadcast message. The MS shall interpret this IE as follows:
- Ciphering Key Flag(previous message) = Ciphering Key Flag(this message) => Deciphering Key not changed.
- Ciphering Key Flag(previous message) <> Cipher Key Flag(this message) => Deciphering Key changed.
ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 10 ETSI TS 144 035 V13.0.0 (2016-01)
Cipher On/Off
This bit indicates whether this broadcast message has been ciphered or not. The RTD Drift Factor Values IE, Channel
RTD Values IE, Serving Cell Location IE and Relative Neighbour Location Values IE will be ciphered if ciphering is
active.
- '0' Ciphering Off.
- '1' Ciphering On.
Sector Ind
This bit indicates whether this broadcast message contains BTS Sectored Cell information or not.
- '0' No Sector Information included.
- '1' Sector Information included.
RTD Range
This bit indicates whether the RTD value covers only one time slot period or 8 time slot period. This bit will affect the
RTD field so that there will be need for 3 bits more for RTD if whole 8 time slot period need to be indicated with RTD
value.
- '0' RTD value covers 1 time slot period.
- '1' RTD value covers 8 time slots period.
RTD Accuracy
This contains two bits, which define what will be the accuracy of RTD value in this broadcast message. The accuracy
will be coded as follows.
Table 5: Accuracy Range
1 0 Definition
0 0 1/16 bit accuracy
0 1 1/32 bit accuracy
1 0 1/64 bit accuracy
1 1 1/128 bit accuracy

The RTD accuracy will affect the amount of bits needed to indicate the RTD value. The following table describes the
accuracy related to needed bits.
Table 6: Amount of RTD bits needed
Time Slots Accuracy Amount of Bits Needed
1/16 12 bits
1/32 13 bits
1
1/64 14 bits
1/128 15 bits
1/16 15 bits
1/32 16 bits
8
1/64 17 bits
1/128 18 bits

RTD Drift Factors Present
This bit indicates whether the RTD Drift Factors are present in this broadcast message. If RTDs Present bit indicates
that the RTD Values are not included into this broadcast message, the state of this bit should be ignored and the RTD
Drift Factors are not present in this broadcast message.
- '0' RTD Drift Factors are not present in the message.
- '1' RTD Drift Factors are present in the message.
ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 11 ETSI TS 144 035 V13.0.0 (2016-01)
RTDs Present
This bit indicates whether RTD Values IE is present in this broadcast or not.
- '0' RTD Values IE not present.
- '1' RTD Values IE present.
Number of Neighbours
These 5 bits are indicating the amount of neighbours are in System Information Neighbour List according to which this
broadcast message was created. The number of neigbours indicated here makes sure that MS can decode back this
broadcast message IEs as they were originally sended. If the MS has received different amount of neighbours in System
Information Neighbour List than indicated in this field in broadcast message, the MS should ignore this broadcast
message.
Range: 1 - 32 Neighbours.
4.1.1.2 Reference Time IE
The Reference Time IE gives information about the time when the RTD values in the broadcast message are calculated.
The Reference Time IE contains the serving cell frame number modulo 131072 with 7 LSB bits omitted. The resolution
of this Reference Time IE is thus 0.59 s. The Reference Time IE has 10 minutes periodicy. This IE is mandatory.
Range: 0 - 1023.
4.1.1.3 Ciphering Serial Number IE
The Ciphering Serial Number IE contains the serial number used in ciphering process of the broadcast message. The IE
contains two octets, MSB part and LSB part. The serial number range is 0 - 65535. This IE is conditional and it is
present only if the ciphering flag is active in Message Structure Definition IE.
Table 7: Ciphering Serial Number IE
MSB LSB
Ciphering Serial Number (8 bits) Ciphering Serial Number (8 bits)

4.1.1.4 Time Slot Scheme IE
This information element contains information about the serving cell channel and neighbour channel time slot scheme.
The list starts with Serving Cell Channel and the rest of the list is in the same order as the neighbours in the System
Information Neighbour List. For each list member there is one bit reserved to indicate whether the channel has
156.25 bits time slot duration or 156/157 bits time slot duration. This field is varying length depending on amount of
neighbours of System Information Neighbour List (max 32) and maximum length of this IE is 33 bits (1+32 bits). The
Serving Cell Channel time slot scheme is always indicated as the first (MSB) element of this field. This IE is
mandatory.
- '0' 156.25 bits time slot duration.
- '1' 156/157 bits time slot duration.
Table 8: Time Slot Scheme
Serving Cell Ch (MSB) Neigh Ch … Neigh Ch Neigh Ch Neigh Ch (LSB)
last 3 2 1
0/1 0/1 … 0/1 0/1 0/1

ETSI

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3GPP TS 44.035 version 13.0.0 Release 13 12 ETSI TS 144 035 V13.0.0 (2016-01)
4.1.1.5 Neighbour Bitmap Definition IE
This IE defines which neighbours from System Information Neighbour List are included in this message. The IE is
conditional and included only if Message Structure Definition IE's Neighbour List Map indicates the use of this
Neighbour Bitmap Definition. The list is in the same order as the neighbours in the System Information Neighbour List,
the last member of the list presented as the MSB element of this field. For each Neighbour List channel number there is
one bit reserved to indicate whether the neighbour is included into this broadcast message. This field is varying length
depending on the amount of neighbours of System Information Neighbour List (max 32) and maximum length of this IE
is 32 bits.
- '0' Neighbour not included into this broadcast message.
- '1' Neighbour included into this broadcast message.
Table 9: Neighbour Bitmap Definition
Neigh Ch (MSB) … Neigh Ch Neigh Ch Neigh Ch (LSB)
last 3 2 1
0/1 … 0/1 0/1

4.1.1.6 Sectored Channels Definition IE
This information element defines which neighbours in System Information Neighbour List that are included in this
broadcast message are belonging to sectored BTSs. This IE is conditional and included only if Message Structure
Definition IE's Sector Indicator is active. This field is varying length depending on amount of neighbours included into
this broadcast message (max 32) and the maximum length of
...