ETSI TS 100 392-18-4 V1.1.1 (2012-06)

Technical Specification
Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D) and Direct Mode Operation (DMO);
Part 18: Air interface optimized applications;
Sub-part 4: Net Assist Protocol 2 (NAP2)

2 ETSI TS 100 392-18-4 V1.1.1 (2012-06)

Reference
DTS/TETRA-03220
Keywords
air interface, location, TETRA, V+D
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ETSI
3 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
Contents
Intellectual Property Rights . 6
Foreword . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 9
4 Net Assist Protocol . 10
4.1 General . 10
4.2 Location information protocol system architecture . 10
4.3 Net assist protocol service description . 11
4.3.1 General on services . 11
4.3.2 Services available at the NAP-SAP . 11
4.3.3 Service primitives at the NAP-SAP . 11
4.3.4 Service primitive parameters at the NAP-SAP . 12
4.3.5 State description . 12
5 Net assist protocol description . 12
5.1 Description of information elements . 12
5.1.1 General on network assistance information elements . 12
5.2 Information flows . 12
5.2.1 General on information flows . 12
5.2.2 Transport layer requirements . 13
5.2.3 Pseudo-segmentation . 13
5.2.4 NAP2 duplicate detection . 13
5.2.5 NAP2 Acknowledgement . 14
5.2.5.1 General . 14
5.2.5.2 Procedure related to acknowledgement . 14
5.2.6 NAP2 retransmission . 15
5.2.6.1 General . 15
5.2.6.2 Procedure related to Retransmission . 15
5.2.7 MS receiving network assistance . 16
5.2.8 MS receiving network assistance and sending response . 16
5.2.9 MS requesting network assistance . 16
5.2.10 MS requesting network assistance and receiving a reject . 17
5.2.11 Allocation of entities . 17
5.3 Procedures . 17
5.3.1 General on procedures . 17
5.3.2 Service availability . 17
5.3.3 Rejection of request for assistance . 18
5.3.4 Routing net assistance to specific terminal groups . 18
5.4 GNSS assistance types . 18
5.4.1 GNSS Ephemeris assistance . 19
5.4.2 GNSS Almanac assistance . 19
5.4.3 GNSS Ionosphere and UTC correction assistance . 19
5.4.4 GNSS Time assistance . 19
5.4.5 Location assistance . 20
6 Net assist protocol coding requirements. 20
6.1 General . 20
6.2 Net assist protocol PDU definitions . 21
6.2.1 Net assist protocol description tables . 21
6.2.1.1 LPP-PDU-Definitions . 22
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4 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
6.2.1.2 NAP-Message . 23
6.2.1.3 LPP-MessageBody . 24
6.2.1.4 NAP-TransactionID . 24
6.2.2 Common IEs . 24
6.2.2.1 Abort . 25
6.2.2.2 Error . 25
6.2.2.3 CommonIEsRequestAssistanceData . 25
6.2.2.4 CommonIEsProvideAssistanceData . 25
6.2.2.5 CommonIEsAbort . 26
6.2.2.6 CommonIEsError . 26
6.2.2.7 RequestAssistanceData . 27
6.2.2.8 ProvideAssistanceData . 27
6.2.2.9 A-GNSS-ProvideAssistanceData . 28
6.2.2.10 GNSS-CommonAssistData . 28
6.2.2.11 GNSS-GenericAssistData . 28
6.2.3 GNSS Assistance Data Elements . 29
6.2.3.1 GNSS-ReferenceTime . 29
6.2.3.2 GNSS-SystemTime . 30
6.2.3.3 GPS-TOW-Assist . 31
6.2.3.4 NetworkTime . 32
6.2.3.5 GNSS-ReferenceLocation . 32
6.2.3.6 EllipsoidPointWithAltitudeAndUncertaintyEllipsoid . 33
6.2.3.7 GNSS-IonosphericModel . 33
6.2.3.8 KlobucharModelParameter . 33
6.2.3.9 NeQuickModelParameter . 34
6.2.3.10 GNSS-EarthOrientationParameters . 34
6.2.3.11 GNSS-TimeModelList . 35
6.2.3.12 GNSS-DifferentialCorrections . 36
6.2.3.13 GNSS-NavigationModel . 38
6.2.3.14 StandardClockModelList . 40
6.2.3.15 NAV-ClockModel . 41
6.2.3.16 CNAV-ClockModel . 42
6.2.3.17 GLONASS-ClockModel . 43
6.2.3.18 SBAS-ClockModel . 43
6.2.3.19 NavModelKeplerianSet . 44
6.2.3.20 NavModelNAV-KeplerianSet . 45
6.2.3.21 NavModelCNAV-KeplerianSet . 47
6.2.3.22 NavModel-GLONASS-ECEF . 48
6.2.3.23 NavModel-SBAS-ECEF . 49
6.2.3.24 GNSS-RealTimeIntegrity . 50
6.2.3.25 GNSS-DataBitAssistance . 50
6.2.3.26 GNSS-AcquisitionAssistance. 52
6.2.3.27 GNSS-Almanac . 54
6.2.3.28 AlmanacKeplerianSet . 55
6.2.3.29 AlmanacNAV-KeplerianSet. 56
6.2.3.30 AlmanacReducedKeplerianSet . 57
6.2.3.31 AlmanacMidiAlmanacSet . 58
6.2.3.32 AlmanacGLONASS-AlmanacSet . 59
6.2.3.33 AlmanacECEF-SBAS-AlmanacSet. 60
6.2.3.34 GNSS-UTC-Model . 61
6.2.3.35 UTC-ModelSet1 . 62
6.2.3.36 UTC-ModelSet2 . 62
6.2.3.37 UTC-ModelSet3 . 63
6.2.3.38 UTC-ModelSet4 . 64
6.2.3.39 GNSS-AuxiliaryInformation . 65
6.2.4 GNSS Assistance Data Request . 65
6.2.4.1 A-GNSS-RequestAssistanceData . 65
6.2.4.2 GNSS-CommonAssistDataReq . 66
6.2.4.3 GNSS-GenericAssistDataReq . 66
6.2.5 GNSS Assistance Data Request Elements . 67
6.2.5.1 GNSS-ReferenceTimeReq . 67
6.2.5.2 GNSS-ReferenceLocationReq . 68
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5 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
6.2.5.3 GNSS-IonosphericModelReq. 68
6.2.5.4 GNSS-EarthOrientationParametersReq . 68
6.2.5.5 GNSS-TimeModelListReq . 69
6.2.5.6 GNSS-DifferentialCorrectionsReq . 69
6.2.5.7 GNSS-NavigationModelReq . 69
6.2.5.8 GNSS-RealTimeIntegrityReq . 71
6.2.5.9 GNSS-DataBitAssistanceReq . 71
6.2.5.10 GNSS-AcquisitionAssistanceReq . 72
6.2.5.11 GNSS-AlmanacReq . 72
6.2.5.12 GNSS-UTC-ModelReq . 73
6.2.5.13 GNSS-AuxiliaryInformationReq . 73
6.2.6 GNSS Error Elements . 74
6.2.6.1 A-GNSS-Error . 74
6.2.6.2 GNSS-LocationServerErrorCauses . 74
6.2.6.3 GNSS-TargetDeviceErrorCauses . 74
6.2.7 Common GNSS Information Elements. 75
6.2.7.1 GNSS-ID . 75
6.2.7.2 GNSS-ID-Bitmap . 75
6.2.7.3 GNSS-SignalID . 75
6.2.7.4 GNSS-SignalIDs . 76
6.2.7.5 SBAS-ID . 77
6.2.7.6 SBAS-IDs . 77
6.2.7.7 SV-ID . 77
6.2.7.8 EPDU-Sequence . 78
6.2.8 TETRA Network related IEs . 79
6.2.8.1 Tetra Local Area and Mobile Network Identifier . 79
6.2.8.2 Net assist group address . 79
6.2.8.3 CellGlobalIdTETRA . 79
6.2.8.4 Result code . 80
6.2.8.5 Net assist type . 80
6.2.8.6 Retry interval. 81
History . 82

ETSI
6 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
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://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 Technical Committee Terrestrial Trunked Radio
(TETRA).
The present document is part 18, sub-part 4 of a multi-part deliverable covering the Voice plus Data (V+D), as
identified below:
EN 300 392-1: "General network design";
EN 300 392-2: "Air Interface (AI)";
EN 300 392-3: "Interworking at the Inter-System Interface (ISI)";
ETS 300 392-4: "Gateways basic operation";
TS 100 392-5: "Peripheral Equipment Interface (PEI)";
TS 100 392-7: "Security";
EN 300 392-9: "General requirements for supplementary services";
EN 300 392-10: "Supplementary services stage 1";
TS 100 392-11: "Supplementary services stage 2";
EN 300 392-12: "Supplementary services stage 3";
ETS 300 392-13: "SDL model of the Air Interface (AI)";
ETS 300 392-14: "Protocol Implementation Conformance Statement (PICS) proforma specification";
TS 100 392-15: "TETRA frequency bands, duplex spacings and channel numbering";
TS 100 392-16: "Network Performance Metrics";
TR 100 392-17: "TETRA V+D and DMO specifications";
TS 100 392-18: "Air interface optimized applications":
Sub-part 1: "Location Information Protocol (LIP)";
Sub-part 2: "Net Assist Protocol (NAP)";
Sub-part 3: "Direct mode Over The Air Management protocol (DOTAM)";
Sub-part 4: "Net Assist Protocol 2 (NAP2)".
NOTE: Part 3, sub-parts 6 and 7 (Speech format implementation), part 4, sub-part 3 (Data networks gateway),
part 10, sub-part 15 (Transfer of control), part 13 (SDL) and part 14 (PICS) of this multi-part deliverable
are in status "historical" and are not maintained.
ETSI
7 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
1 Scope
The present document defines Net Assist Protocol 2 that is optimized for TETRA air interface. It defines services:
• allowing information to be passed to a location determining entity;
• allowing a location determining entity to request assistance information.
The information passed to the location determining entity, when relevant, reflects the content and format of the
equivalent information (navigation data) which passes from satellites to the location determining entity.
The protocol is capable of supporting more than one position determining technology. Presently it covers multiple
GNSS, and is extensible to all network positioning methods.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
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 necessary for the application of the present document.
[1] IS-GPS-200F: "Navstar GPS Space Segment/Navigation User Interfaces", September 21, 2011.
NOTE: Available at: http://www.gps.gov/technical/icwg/#is-gps-200
[2] ETSI EN 300 392-1: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 1: General network design".
[3] ETSI EN 300 392-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air
Interface (AI)".
[4] ETSI TS 100 392-18-1: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D) and Direct
Mode Operation (DMO); Part 18: Air interface optimized applications; Sub-part 1: Location
Information Protocol (LIP)".
[5] IS-GPS-705B: "Navstar GPS Space Segment/User Segment L5 Interfaces", September 21, 2011.
[6] IS-GPS-800, Navstar GPS Space Segment/User Segment L1C Interfaces, September 4, 2008.
[7] IS-QZSS, Quasi Zenith Satellite System Navigation Service, Interface Specifications for QZSS,
Ver.1.1, July 31, 2009.
[8] Galileo OS Signal in Space ICD (OS SIS ICD), Issue 1.1, Galileo Joint Undertaking, September
2010.
NOTE Available at: http://ec.europa.eu/enterprise/policies/satnav/galileo/open-service/index_en.htm
[9] Global Navigation Satellite System GLONASS, Interface Control Document, Version 5.1, 2008.
[10] Specification for the Wide Area Augmentation System (WAAS), US Department of
Transportation, Federal Aviation Administration, DTFA01-96-C-00025, 2001.
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8 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
[11] RTCM-SC104, RTCM Recommended Standards for Differential GNSS Service (v.2.3),
August 20, 2001.
[12] ITU-T Recommendation X.680: "Information technology - Abstract Syntax Notation One,
(ASN.1): Specification of basic notation".
[13] ITU-T Recommendation X.681: "Information technology - Abstract Syntax Notation One,
(ASN.1): Information object specification".
[14] ITU-T Recommendation X.690: "Information technology - ASN.1 encoding rules: Specification of
Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding
Rules (DER)". OSI networking and syste aspects - Abstract Syntax Notation One (ASN.1).
[15] ITU-T Recommendation X.691: "Information technology - ASN.1 encoding rules: Specification of
Packed Encoding Rules (PER)".
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TS 136 355: "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); LTE Positioning
Protocol (LPP) (3GPP TS 36.355 version 10.4.0 Release 10)".
[i.2] LPP Extensions Specification, Open Mobile Alliance OMA-TS-LPPe-V1-0-20110929-C.
[i.3] ETSI TS 144 031: "Digital cellular telecommunications system (Phase 2+); Location Services
(LCS); Mobile Station (MS) - Serving Mobile Location Centre (SMLC) Radio Resource LCS
Protocol (RRLP) (3GPP TS 44.031 version 10.0.0 Release 10)".
[i.4] ETSI TS 100 392-18-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D) and Direct
Mode Operation (DMO); Part 18: Air interface optimized applications; Sub-part 2: Net Assist
Protocol (NAP)".
[i.5] ETSI TS 143 059: "Digital cellular telecommunications system (Phase 2+); Functional stage 2
description of Location Services (LCS) in GERAN (3GPP TS 43.059 version 10.0.0 Release 10)".
[i.6] ETSI TS 123 032: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Universal Geographical Area Description (GAD) (3GPP
TS 23.032 version 10.0.0 Release 10)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in EN 300 392-2 [3] and the following apply:
assistance server: entity that maintains location assistance information and sends location assistance information to its
clients
navigation data: data that is passed from satellites to the location determining entity and supports said location
determination, for example by defining satellite positioning
NOTE: For GPS assistance this data is defined by ICD-GPS-200 [1], IS-GPS-705 [5], IS-GPS-800 [6], for QZSS,
it is defined in IS-QZSS, [7], for Galileo in OS SIS ICD [8], and for GLONASS in GLONASS ICD [9].
TETRA domain: all entities that are addressed using TETRA defined addresses and understand the binary format of
Net Assist Protocol
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9 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
A-GNSS Assisted- Global Navigation Satellite System
AGNSS Assisted Global Navigation Satellite System
BS Base Station
C Conditional
CGI Cell Global Identification
CNAV Civil Navigation
DGNSS GNSS Differential Corrections
DMO Direct Mode Operation
DN Day Number
ECEF Earth Centred Earth Fixed (coordinate system)
ECI Earth Centered Inertial (coordinate system)
EGNOS European Geostationary Navigation Overlay ServiceGAGAN GPS Aided Geo Augmented
Navigation
EOP Earth Orientation Parameters
EPDU Extended Protocol Data Unit
FDMA Frequency Division Multiple Access
FE Functional Entity
FEC Forward Error Correction
GLONASS GLObal'naya NAvigatsionnaya Sputnikovaya Sistema
NOTE: Engl.: Global Navigation Satellite System
GNSS Global Navigation Satellite System
GPS Global Positioning System
ICD Interface Control Document
IE Information Element
IOD Issue of Data
IODC Issue of Data Clock
LA Location Area
LIP Location Information Protocol
LOC LOCation group (at OMA)
LPP LTE Positioning Protocol
M Mandatory
MNI Mobile Network Identity
MO-LR Mobile Originated Location Request
MS Mobile Station
NAP Net Assist Protocol
NAV Navigation
OMA Open Mobile Alliance
PDU Protocol Data Unit
PRC Pseudo-Range Correction
PRN Pseudo Random Noise
QZSS Quasi-Zenith Satellite System
QZS-L Quasi-Zenith Satellite System
QZST Quasi-Zenith Satellite Time
RRC Range-Rate Correction
SAP Service Access Point
SBAS Space Based Augmentation System
SDS Short Data Service
SDS-TL Short Data Service - Transport Layer
SNDCP SAP SubNetwork Dependent Convergence Protocol Service Access Point
SV Space Vehicle
SV-ID Satellite Vehicle Identifier
TBD To Be Defined
TCP Transmission Control Protocol
TOD Time Of Day
TOW Time Of Week
UDP User Datagram Protocol
UDRE User Differential Range Error
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10 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
URA User Range Accuracy
UTC Universal Coordinated Time
WAAS Wide Area Augmentation System
WGS-84 World Geodetic System 1984
4 Net Assist Protocol
4.1 General
The Net Assist Protocol (NAP) is a TETRA air interface optimized application layer protocol that can utilize various
transport mechanisms.
The net assist protocol may use SDS-TL service at SDS-TL SAP, refer to EN 300 392-2 [3], clauses 29.1.1 to 29.5.12 in
the case of TETRA MS, though it does not use SDS-TL transport mechanisms to ensure delivery. The same protocol
can use packet data at SNDCP SAP as defined in EN 300 392-2 [3], clause 28 in the case of TETRA MS.
The net assist protocol defines an extendable protocol that can provide net assist information, initially in a GNSS
technology based location determination scenario. Resource optimization is achieved by ensuring data is transported in
its most compact form as binary data and not in an expanded human readable form. Because of the volume of data and
because of the number of satellites it should be noted that some messages have a length which exceeds 500 bits and
multiple messages (one for each satellite) may need to be sent.
The net assist protocol can be used in various system configurations including:
• MS to assistance server communication (request for assistance information).
• Assistance server to MS communication (transmission of assistance information).
• MS to MS communication (request for and transmission of assistance information).
NOTE: Although NAP2 supports direct MS to individual MS communication; the use of it is discouraged as the
optimized air interface usage may be compromised. One possibility to maintain air interface optimization
is the use of a group address as the destination address.
4.2 Location information protocol system architecture
Physical entities identified for the purpose of the present document are:
• Mobile Station (MS) and location accessory requiring net assist information. It is referred as the "Target
Device" of location.
• Assistance server inside the TETRA domain with available net assist information (which may have been
sourced outside the TETRA domain and passed to it using a suitable protocol which is outside the scope of the
present document). It is also called a "Location Server".
How the assistance server acquires its net assist information and how it decides when to make that information available
are outside the scope of the present document.
Similarly, how the MS determines when and what assistance information is required is outside the scope of the present
document.
The assistance information exchange contains scenarios:
• MS determines that it would like assistance and makes a request to the assistance server for information.
• Assistance server to MS, where the assistance server has net assist information, and the assistance server
distributes the information to MS.
• MS to MS net assist information exchange without any action in any other entities.
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11 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
For the purposes of the present document, the TETRA domain consists of entities that are addressable using TETRA
addressing and understand the net assist protocol NAP in the binary format of the protocol.
For the purposes of the present document protocol Functional Entities (FE) are used in some clauses instead of physical
entities:
FE1: MS requiring net assist information.
FE2: Assistance server.
Figure 4.2.1 defines a typical scenario for the net assist protocol usage.
In figure 4.2.1 the MS FE1 requests assistance information from the assistance server FE2.
In figure 4.2.1 the assistance server FE2 acts as the distribution point for assistance information to one or more MSs
FE1 requiring and able to accept assistance information.
Assistance info destination Assistance server
FE1 FE2
TETRA domain
Figure 4.2.1: Simple system with assistance server in TETRA domain
4.3 Net assist protocol service description
4.3.1 General on services
The majority of the location information protocol (TS 100 392-18-1 [4]) is independent of position determination
technology. However, the technology currently used is frequently GPS (or other GNSS in short term) and in this case a
net assistance delivery service is defined. Assistance data, delivered via the TETRA network, can improve the
performance of some GNSS receivers, particularly when they are in areas of poor GNSS satellite signal reception, such
that they cannot reliably receive navigation data from the satellites themselves. Additional information is made
available in the form of time and location (with uncertainty) assistance data. This release support all known Global
Navigation Satellite System (GNSS) covering GPS as well as constellation currently partial as GLONASS, COMPASS
or yet to be launched as Galileo, QZSS. Support of various GNSS allow better position determination in polar region,
sub-tropical regions, or difficult environment where only a few satellites are visible , and more availability. The
th
structure of the assistance is consistent with the AGNSS data in the LPP [13] from 3GPP, established for the 4
generation of Public Mobile Land Network (PLMN), and it semantic and usage is based on the relevant ICD for each
supported constellation.
4.3.2 Services available at the NAP-SAP
FE2 may support network assistance delivery to FE1s, typically using group addressing. For the case that network
assistance is delivered to an individual FE1, FE2 may ask for and receive an acknowledgement.
FE1 may support requesting network assistance from FE2. FE2 may respond by delivering network assistance as above.
4.3.3 Service primitives at the NAP-SAP
Service primitives at the NAP-SAP define service access. This service primitive definition assumes that the entity using
these service primitives gets all trigger invocations by other means and those are outside the scope of the present
document.
NAP-Net assist provide request: this primitive is used to send network assistance data.
NAP-Net assist provide indication: this primitive is used to receive network assistance data.
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12 ETSI TS 100 392-18-4 V1.1.1 (2012-06)
NAP-Net assist provide response: this primitive is used to acknowledge network assistance data.
NAP-Net assist provide confirmation: this primitive is used to receive network assistance data acknowledgements.
NAP-Net assist demand request: this primitive is used to request (demand) network assistance.
NAP-Net assist demand indication: this primitive is used to receive requests (demands) for network assistance.
NAP-Net assist reject response: this primitive is used to reject the network assistance request.
NAP-Net assist reject confirmation: this primitive is used to receive a network assistance rejection.
4.3.4 Service primitive parameters at the NAP-SAP
As the present document does not define a physical access to the NAP-SAP, the description of the conceptual service
primitives is minimized and the service primitive parameters are implied by the information elements in the PDUs.
4.3.5 State description
The net assist protocol uses a single state at the FE that does not link request and response together. At that state NAP
sends and receives all the service primitives and PDUs. If it is important for an application to get e.g. response to a
specific request or receive an acknowledgement before proceeding, then the application should use a suitable state
machine or other means to make that possible.
5 Net assist protocol description
5.1 Description of information elements
5.1.1 General on network assistance information elements
The forms of GNSS network assistance supported are defined by Net assist type grouped in common assistance (which
are provided once for all constellations) and generic assistance data that are provided for satellites of a given
constellation, and in some case, one signal broadcasted by this constellation, in a generic format. ReferenceTime,
ReferenceLocation, Ionosphere and EarthOrientationParameters are defined in a common model, whereas Almanac
data, Almanac reference week, Ephemeris and clock data, Real-time integrity, UTC correction data, Differential
Corrections, Data Bit Assistance, Acquisition Assistance and AuxiliaryInformation are all defined in the same model as
variant data model with respect to the respective ICD for the constellation (e.g. ICD-GPS-200 [1] for GPS).
Which assistance type and for which constellation is either specified by the MS requesting network assistance, or by
configuration in the network for the set of GNSS enabled MS. There is a tradeoff between the required bandwidth and
the benefits provided by the assistance on a given constellation.
5.2 Information flows
5.2.1 General on information flows
The information flows in clauses 5.2.2 to 5.2.5 present ty
...