ETSI TS 101 376-1-3 V3.3.1 (2012-12)

GEO-Mobile Radio Interface Specifications (Release 3); Third Generation Satellite Packet Radio Service; Part 1: General specifications; Sub-part 3: General System Description; GMR-1 3G 41.202

RTS/SES-00328-1-3

General Information

• Status: Published
• Publication Date: 20-Dec-2012
• Technical Committee: SES SCN - Satellite Communications and Navigation
• Current Stage: 12 - Completion
• Due Date: 02-Jan-2013
• Completion Date: 21-Dec-2012
• Mandate: M/496

Standards Content (Sample)

Technical Specification
GEO-Mobile Radio Interface Specifications (Release 3);
Third Generation Satellite Packet Radio Service;
Part 1: General specifications;
Sub-part 3: General System Description;
GMR-1 3G 41.202
GMR-1 3G 41.202 2 ETSI TS 101 376-1-3 V3.3.1 (2012-12)

Reference
RTS/SES-00328-1-3
Keywords
3G, generic, GMPRS, GMR, GSM, GSO,
interface, MES, mobile, MSS, radio, satellite
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© European Telecommunications Standards Institute 2012.
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ETSI
GMR-1 3G 41.202 3 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
Contents
Intellectual Property Rights . 4
Foreword . 4
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Abbreviations . 9
4 Introduction to the GMR-1 3G specifications . 10
4.1 History of the GMR-1 air interface . 10
4.2 Key features of the GMR-1 3G air interface . 12
5 Description of the air interface . 16
5.1 Frame structure . 16
5.2 Channels . 17
5.2.1 Traffic channels . 17
5.2.1.1 Cell Broadcast Channels . 19
5.2.2 PUI and PRI . 19
5.2.3 Control channels . 20
5.2.3.1 Broadcast Channels . 20
5.2.3.1.1 FCCH or FCCH3 . 20
5.2.3.1.2 GBCH or GBCH3. 20
5.2.3.1.3 BCCH . 21
5.2.3.2 Common Control Channels (CCCH) . 21
5.2.3.2.1 PCH . 21
5.2.3.2.2 RACH or RACH3. 21
5.2.3.2.3 AGCH . 21
5.2.3.2.4 BACH . 21
5.2.3.2 Dedicated Control Channels. 21
5.3 FEC . 21
5.4 Modulation . 22
5.5 Power Control and Link Adaptation . 24
5.5.1 General . 24
5.5.2 Link Adaptation . 24
5.5.3 Power Control . 24
5.6 Control channel organization . 24
5.7 MAC/RLC Layer Design . 27
5.8 RRC Layer Design . 29
5.9 PDCP Layer Design . 30
5.10 Terminal types . 31
Annex A (informative): Bibliography . 32
History . 33

ETSI
GMR-1 3G 41.202 4 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
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 Satellite Earth Stations and
Systems (SES).
The contents of the present document are subject to continuing work within TC-SES and may change following formal
TC-SES approval. Should TC-SES modify the contents of the present document it will then be republished by ETSI
with an identifying change of release date and an increase in version number as follows:
Version 3.m.n
where:
• the third digit (n) is incremented when editorial only changes have been incorporated in the specification;
• the second digit (m) is incremented for all other types of changes, i.e. technical enhancements, corrections,
updates, etc.
The present document is part 1, sub-part 3 of a multi-part deliverable covering the GEO-Mobile Radio Interface
Specifications (Release 3); Third Generation Satellite Packet Radio Service, as identified below:
Part 1: "General specifications":
Sub-part 1:   "Abbreviations and acronyms; GMPRS-1 01.004";
Sub-part 2:   "Introduction to the GMR-1 family; GMR-1 3G 41.201";
Sub-part 3: "General System Description; GMR-1 3G 41.202";
Part 2: "Service specifications";
Part 3: "Network specifications";
Part 4: "Radio interface protocol specifications";
Part 5: "Radio interface physical layer specifications";
Part 6: "Speech coding specifications";
Part 7: "Terminal adaptor specifications".
ETSI
GMR-1 3G 41.202 5 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
Introduction
GMR stands for GEO (Geostationary Earth Orbit) Mobile Radio interface, which is used for Mobile Satellite
Services (MSS) utilizing geostationary satellite(s). GMR is derived from the terrestrial digital cellular standard GSM
and supports access to GSM core networks.
The present document is part of the GMR Release 3 specifications. Release 3 specifications are identified in the title
and can also be identified by the version number:
• Release 1 specifications have a GMR 1 prefix in the title and a version number starting with "1" (V1.x.x).
• Release 2 specifications have a GMPRS 1 prefix in the title and a version number starting with "2" (V2.x.x).
• Release 3 specifications have a GMR-1 3G prefix in the title and a version number starting with "3" (V3.x.x).
The GMR release 1 specifications introduce the GEO-Mobile Radio interface specifications for circuit mode Mobile
Satellite Services (MSS) utilizing geostationary satellite(s). GMR release 1 is derived from the terrestrial digital cellular
standard GSM (phase 2) and it supports access to GSM core networks.
The GMR release 2 specifications add packet mode services to GMR release 1. The GMR release 2 specifications
introduce the GEO-Mobile Packet Radio Service (GMPRS). GMPRS is derived from the terrestrial digital cellular
standard GPRS (included in GSM Phase 2+) and it supports access to GSM/GPRS core networks.
The GMR release 3 specifications evolve packet mode services of GMR release 2 to 3rd generation UMTS compatible
services. The GMR release 3 specifications introduce the GEO-Mobile Radio Third Generation (GMR-1 3G) service.
Where applicable, GMR-1 3G is derived from the terrestrial digital cellular standard 3GPP and it supports access to
3GPP core networks.
Due to the differences between terrestrial and satellite channels, some modifications to the GSM or 3GPP standard are
necessary. Some GSM and 3GPP specifications are directly applicable, whereas others are applicable with
modifications. Similarly, some GSM and 3GPP specifications do not apply, while some GMR specifications have no
corresponding GSM or 3GPP specification.
Since GMR is derived from GSM and 3GPP, the organization of the GMR specifications closely follows that of GSM
or 3GPP as appropriate. The GMR numbers have been designed to correspond to the GSM and 3GPP numbering
system. All GMR specifications are allocated a unique GMR number. This GMR number has a different prefix for
Release 2 and Release 3 specifications as follows:
• Release 1: GMR n xx.zyy
• Release 2: GMPRS n xx.zyy
• Release 3: GMR-1 3G xx.zyy
where:
- xx.0yy (z = 0) is used for GMR specifications that have a corresponding GSM or 3GPP specification. In
this case, the numbers xx and yy correspond to the GSM or 3GPP numbering scheme.
- xx.2yy (z = 2) is used for GMR specifications that do not correspond to a GSM or 3GPP specification. In
this case, only the number xx corresponds to the GSM or 3GPP numbering scheme and the number yy is
allocated by GMR.
- n denotes the first (n = 1) or second (n = 2) family of GMR specifications.
ETSI
GMR-1 3G 41.202 6 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
A GMR system is defined by the combination of a family of GMR specifications and GSM and 3GPP specifications as
follows:
• If a GMR specification exists it takes precedence over the corresponding GSM or 3GPP specification (if any).
This precedence rule applies to any references in the corresponding GSM or 3GPP specifications.
NOTE: Any references to GSM or 3GPP specifications within the GMR specifications are not subject to this
precedence rule. For example, a GMR specification may contain specific references to the corresponding
GSM or 3GPP specification.
• If a GMR specification does not exist, the corresponding GSM or 3GPP specification may or may not apply.
The applicability of the GSM specifications is defined in TS 101 376-1-2 [2].
ETSI
GMR-1 3G 41.202 7 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
1 Scope
The present document is an introduction to Release 3 of the GMR-1 system (GMR-1 3G) and the associated Release 3
of the air interface specification. It is intended to point out some of the differences between the cellular 3GPP and GSM
system and the mobile satellite GMR-1 system.
The GMR-1 system is designed to provide mobile services via a single geostationary satellite as compared to the
thousands of geographically separated cell sites that are used by a typical GSM system. This offers both challenges to
be overcome and opportunities for enhanced services and features.
GMR-1 3G is an extension of the published ETSI TS 101 376 and TIA (S-J-STD-782) specifications for mobile satellite
communications, GMR-1, to support IMT-2000 services. GMR-1 is currently used in mobile satellite systems covering
Europe, Africa, Asia and Middle East. GMR-1 3G is currently being deployed in North America.
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
reference 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.
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 Release 7 or to the latest version of that document in the latest release
less than 7.
In the case of a reference to a GMR-1 3G document, a non-specific reference implicitly refers to the latest version of
that document in the same Release as the present document.
[1] ETSI TS 101 376-1-1: "GEO-Mobile Radio Interface Specifications (Release 2) General Packet
Radio Service; Part 1: General specifications; Sub-part 1: Abbreviations and acronyms;
GMPRS-1 01.004".
NOTE: This is a reference to a GMR-1 Release 2 specification. See the Introduction for more details.
[2] ETSI TS 101 376-1-2: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 1: General specifications; Sub-part 2: Introduction to the
GMR-1 family; GMR-1 3G 41.201".
[3] Void.
[4] Void.
[5] ETSI TS 101 376-4-8: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 4: Radio interface protocol specifications; Sub-part 8: Mobile
Radio Interface Layer 3 Specifications; GMR-1 3G 44.008".
[6] ETSI TS 101 376-5-2: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 5: Radio interface physical layer specifications;
Sub-part 2: Multiplexing and Multiple Access; Stage 2 Service Description; GMR-1 3G 45.002".
ETSI
GMR-1 3G 41.202 8 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
[7] ETSI TS 101 376-5-3: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 5: Radio interface physical layer specifications;
Sub-part 3: Channel Coding; GMR-1 3G 45.003".
[8] ETSI TS 101 376-5-4: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 5: Radio interface physical layer specifications;
Sub-part 4: Modulation; GMR-1 3G 45.004".
[9] ETSI TS 101 376-5-5: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 5: Radio interface physical layer specifications;
Sub-part 5: Radio Transmission and Reception; GMR-1 3G 45.005".
[10] ETSI TS 101 376-5-6: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 5: Radio interface physical layer specifications;
Sub-part 6: Radio Subsystem Link Control; GMR-1 3G 45.008".
[11] ETSI TS 101 376-5-7: "GEO-Mobile Radio Interface Specifications (Release 3); Third Generation
Satellite Packet Radio Service; Part 5: Radio interface physical layer specifications;
Sub-part 7: Radio Subsystem Synchronization; GMR-1 3G 45.010".
[12] ETSI TS 101 376-4-12: "GEO-Mobile Radio Interface Specifications (Release 3); Third
Generation Satellite Packet Radio Service; Part 4: Radio interface protocol specifications;
Sub-part 12: Mobile Earth Station (MES) - Base Station System (BSS) interface; Radio Link
Control/Medium Access Control (RLC/MAC) protocol; GMR-1 3G 44.060".
[13] ETSI TS 101 376-4-13: "GEO-Mobile Radio Interface Specifications (Release 3); Third
Generation Satellite Packet Radio Service; Part 4: Radio interface protocol specifications;
Sub-part 13: Radio Resource Control (RRC) protocol; Iu Mode; GMR-1 3G 44.118".
[14] ETSI TS 144 018: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface
layer 3 specification; Radio Resource Control (RRC) protocol (3GPP TS 44.018)".
[15] ETSI TS 144 118: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface
layer 3 specification, Radio Resource Control (RRC) protocol; Iu mode (3GPP TS 44.118)".
[16] ETSI TS 101 376-4-15: "GEO-Mobile Radio Interface Specifications (Release 3); Third
Generation Satellite Packet Radio Service; Part 4: Radio interface protocol specifications;
Sub-part 15: Packet Data Convergence Protocol (PDCP) specification; GMR-1 3G 25.323".
[17] ETSI TS 101 376-4-14: "GEO-Mobile Radio Interface Specifications (Release 3); Third
Generation Satellite Packet Radio Service; Part 4: Radio interface protocol specifications;
Sub-part 14: Mobile Earth Station (MES) - Base Station System (BSS) interface; Radio Link
Control/Medium Access Control (RLC/MAC) protocol; Iu Mode; GMR-1 3G 44.160".
[18] ITU-R Recommendation M.1457-6: "Detailed specifications of the radio interfaces of
International Mobile Telecommunications (IMT-2000)".
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] IETF RFC 2236: "Internet Group Management Protocol, Version 2".
ETSI
GMR-1 3G 41.202 9 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
3 Abbreviations
For the purposes of the present document, the abbreviations given in TS 101 376-1-1 [1] and the following apply:
APSK Amplitude and Phase Shift Keying
BPSK Binary Phase Shift Keying
DC12 twelve-slot Downlink Control
DCH Dedicated CHannel
DTCH Dedicated Traffic CHannel
EDGE Enhanced Data rates for GSM Evolution
FDD Frequency Division Duplex
GBCH3 GPS Broadcast Channel 3
GERAN GSM EDGE Radio Access Network
GMM/SM GPRS Mobility Management and Session Management
GMPRS-1 GEO-Mobile Packet Radio Service - 1
GMR-1 3G GEO-Mobile Radio interface - 1 Third Generation
GRA GERAN Registration Area
GTP GPRS Tunnelling Protocol
GTP-U GPRS Tunnelling Protocol - User plane
IMS IP Multimedia System
IP Internet Protocol
IPv6 Internet Protocol version 6
Iu Interface between BSS and core network
Iu-PS Interface between BSS and core network - Packet Switched
ksps kilo symbols per second
L1 bis Layer 1 bis
L2 Layer 2
LAPSAT Link Access Protocol for SATellite
LDPC Low Density Parity Check
LLC Logical Link Control
MSS Mobile Satellite Service
MTP-1 Message Transfer Part - 1
MTP-2 Message Transfer Part - 2
MTP-3 Message Transfer Part - 3
NAS Non Access Stratum
Nwk Network
PAPR Peak to Average Power Ratio
PDA Personal Digital Assistant
PDCP Packet Data Convergence Protocol
PDTCH/D Packet Data Traffic Channel/Downlink
PDTCH/U Packet Data Traffic Channel/Uplink
PSD Power Spectral Density
QPSK Quaternary Phase Shift Keying
RACH3 Random Access Channel - 3
RR Radio Resource
RRC Radio Resource Control
SBSS Serving Base Station Subsystem
SES Satellite Earth Stations and Systems
TCP Transmission Control Protocol
TDM Time Division Multiplex
UDP User Datagram Protocol
UL UpLink
VoIP Voice over Internet Protocol
ETSI
GMR-1 3G 41.202 10 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
4 Introduction to the GMR-1 3G specifications
4.1 History of the GMR-1 air interface
The GMR-1 3G air interface is an evolutionary third generation (3G) Mobile Satellite System (MSS) air interface that is
built upon the earlier Release 1 and Release 2 of the GMR-1 air interface.
The GMR-1 development and standardization path follows the evolution of GSM/EDGE Radio Access Network or
GERAN as shown in figure 1.
Version 3.x.x
2012-2013
– Packet switched IP Multimedia
GMR-1 3G – Iu interface – Network side
3GPP
– Up to 590 kbps
– S-band and L-band
Version 2.x.x
DSL+
– Up to 444 kbps (portable)
– Up to 64 kbps (hand-held)
Narrowband
– Up to 144 kbps (portable)
– Packet switched data
R-BGAN
– Gb interface – Network side
Version 1.x.x
– Circuit switched voice and data
GPRS r97 GMPRS
– A interface – Network side
GSM
GMR-1
Figure 1: Evolution of GMR-1 specifications
The GMR-1 air interface specifications were first published in 2001 (GMR-1 Release 1) based on the GSM protocol
architecture with satellite specific optimizations.
The GMR-1 Release 1 radio interface supports compatible services to GSM and reuses the GSM network infrastructure
(see figure 2). It is designed to be used with dual-mode terminals (satellite/terrestrial) allowing the user to roam between
GMR-1 satellite networks and GSM terrestrial networks. Features include spectrally efficient voice, delay tolerant fax,
reliable non-transparent data services up to 9,6 kbps, SMS, cell broadcast services, position-based services, SIM
roaming, high penetration alerting and single-satellite hop terminal-to-terminal calls. A system based on GMR-1
Release 1 is being widely used today in Europe, Africa, Asia and Middle East.
The GMR-1 Release 1 specifications have been revised and updated two additional times in 2002 (Version 1.2.1) and
again in 2005 (Version 1.3.1).
ETSI
GMR-1 3G 41.202 11 ETSI TS 101 376-1-3 V3.3.1 (2012-12)

CMCMCM CMCMCM
MMMMMM MMMMMM
ReReRelllaaayyy
BSSBSSBSSAPAPAP
RRRRRR BSBSBSSAPSAPSAP
RRRRRR
SCSCSCCCCPPP
SCSCSCCCCPPP
LLLAPSAPSAPSATATAT
LLLAAAPSPSPSATATAT
MTMTMTPPP---333
MTMTMTPPP---333
MTMTMTPPP---222
MTMTMTPPP---222
PHPHPHYYY
PHPHPHYYY
MTMTMTPPP---111
MTMTMTPPP---111
UTUTUT 2G2G2G S S SBBBSSSSSS MSMSMSCCC///VVVLLLRRR
GMGMGMRRR ---111 A A Aiiirrr
A IA IA Innnttteeerrrfffaaaccceee
InInInttteeerrrfffaaaccceee
Figure 2: Protocol architecture for control plane (A interface)
In 2003, the GMR-1 air interface was enhanced with the addition of a packet switched data capability and the revised
air interface published as GMR-1 Release 2 or GMPRS-1 (GEO-Mobile Packet Radio System-1). GMPRS-1 provides
IP data services to transportable terminals using GPRS technology with a Gb interface to the core network. Figures 3
and 4 illustrate protocol architecture of the GMPRS-1 air interface for user plane and control plane using Gb interface
towards core network. A number of satellite specific enhancements were introduced at PHY and MAC layers of the
protocol stack to provide improved throughputs and better spectral efficiencies.
AApplppliiccatatiioonn
IPIP IPIP
ReRellaayy
SNSNDDCCPP SNSNDDCCPP GTGTPP GTGTPP
LLCLLC LLLLCC UDPUDP// TTCPCP UDPUDP// TTCPCP
ReRellaayy
RLRLCC BSBSSSGGPP IPIP IPIP
RLRLCC
BSBSSGSGPP
FFrramame e FFrramame e
MAMACC MAMACC L2L2 L2L2
ReRellaayy ReRellaayy
PHPHYY PHPHYY L1L1 b biiss L1L1 b biiss L1L1 L1L1
UUTT 22.55GG SB SBSSSS SSGGSNSN GGGGSSNN
GMGMRR--11
AiAirr GbGb GnGn GiGi
InIntteerrffaaccee
Figure 3: Protocol architecture for user plane (Gb interface)
ETSI
GMR-1 3G 41.202 12 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
ReRellaayy
GMGMMM//SSMM GTGTPP
GMGMMM//SSMM
GTGTPP
LLLLCC LLCLLC UDUDPP UDUDPP
ReRellaayy
RLRLCC BSBSSSGGPP IPIP IPIP
RLRLCC BSBSSSGGPP
FFrramame e FFrramame e
MAMACC MAMACC L2L2 L2L2
ReRellaayy ReRellaayy
PHPHYY PHPHYY L1L1 b biiss L1L1 bi biss L1L1 L1L1
MEMESS SSGGSNSN GGGGSNSN
2.2.55GG S SBBSSSS
GMGMRR--11 A Aiirr
GbGb GGnn
inintteerrffacacee
Figure 4: Protocol architecture for control plane (Gb interface)
GMPRS-1 Version 2.1.1 supports bidirectional packet data rates up to 144 kbps, QoS differentiation across users, and
dynamic link adaptation. GMPRS-1 Version 2.2.1, published in 2005, adds support for narrow band packet data
services to handheld terminals that permit up to 64 kbps on the forward link (downlink) and 28,8 kbps on the return link
(uplink). GMPRS-1 Version 2.3.1, published in 2008, adds support for wideband packet services that increase the
packet data rates to 444 kbps on the forward link and 202 kbps on the return link for A5 size transportable terminals.
The system also permits data rates up to 400 kbps on the return link with an external antenna. This latest set of
specifications uses the state-of-the art techniques in the physical (PHY) layer such as LDPC codes and 32-APSK
modulation and can provide bi-directional streaming services.
A system using the GMR-1 Release 2 specifications has been successfully deployed in the field and is being extensively
used in Europe, Africa, Asia and Middle East.
The present document describes the latest enhancement to the GMR-1 air interface specifications. This corresponds to a
new Release 3 of the GMR-1 specifications, also known as GMR-1 3G. GMR-1 3G was first published in 2009
(version 3.1.1) and again in 2011 (version 3.2.1). GMR-1 3G is based on the adaptation to the satellite environment of
the ETSI TDMA EDGE radio air interface (see ITU-R Recommendation M.1457-6 [18] TDMA Single-Carrier).
GMR-1 3G is therefore the satellite equivalent to EDGE. The protocol architecture is based on 3GPP Release 6 and
beyond, but the air interface is an evolution of the GMR-1 Release 2 air interface. In line with ETSI 3GPP
specifications, the satellite base-station is therefore equivalent to a GERAN. GMR-1 3G is designed to meet the
requirements of the satellite component of the third generation (3G) wireless communication systems.
Systems based on GMR-1 3G air interface specifications are currently being developed for MSS operators around the
world operating in the MSS bands at both L-band and S-band frequencies as defined in TS 101 376-5-5 [9].
4.2 Key features of the GMR-1 3G air interface
The GMR-1 3G specification uses the Iu-PS interface between radio network and core network. The objective is to
allow MSS operators to provide forward-looking IP Multimedia System (IMS) based services. Key features included in
this air interface are:
• Spectrally efficient multi-rate VoIP with zero byte header compression.
• V.44 Data Compression.
• TCP/IP, UDP/IP and RTP/UDP/IP header compression.
• Robust waveforms for link closure with terrestrial form-factor MESs.
• Up to 590 kbps throughput.
• Multiple carrier bandwidth operation.
• Multiple terminal types - Hand-held terminals, PDA, vehicular, portable, fixed, maritime and aeronautical.
• IP Multimedia Services.
ETSI
GMR-1 3G 41.202 13 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
• Differentiated QoS across users and applications.
• Dynamic Link Adaptation.
• IPv6 compatibility.
• Terrestrial/Satellite handovers.
• Beam-to-Beam Handovers.
• Unmodified Non-Access Stratum (NAS) protocols and core network.
• High Penetration Alerting.
• GPS assist including either Earth Centered Earth Fixed coordinates or Keplerian coordiates.
• Cell Broadcast.
• Capability to multiplex support multiple VOIP sessions for one MES.
• Resource efficient Multicast.
• Resource and Delay Efficient Push-To-Talk.
• Regional beams and spot beam operation with or without overlay.
• Flexible traffic-only beam support.
Figures 5 and 6 illustrate the protocol architecture of the GMR-1 3G air interface for user plane and control plane using
the Iu-PS interface towards the core network.
AppApplliiccatatiioonn AAppppllicicaattioionn
TCTCPP //UUDDPP
TCTCPP //UUDDPP
IPIP IPIP
IPIP
ReRellaayy ReRellaayy
PDPDCCPP GTGTPP--UU GTGTP-P-UU GTGTPP--UU
PDPDCCPP GTGTPP--UU
L2L2
RLRLCC RLRLCC UDPUDP UDUDPP UDUDPP UDUDPP
IPIP IPIP
MAMACC MAMACC IPIP IPIP
L2L2
L2L2
L1L1
PHPHYY PHPHYY EEttherhernenett EtEthheerrnnetet
IPIP
L1L1 L1L1
NeNettww ororkk
ReRemmoottee
MMEESS GGMMRR1-1-3G3G SB SBSSSS SGSGSNSN GGGGSSNN
HoHosstt
GMGMRR11--33GG IuIu --PPSS GnGn GiGi

Figure 5: Protocol architecture for user plane (Iu interface)
ETSI
GMR-1 3G 41.202 14 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
NNoonn--AAcccesscess
GMGMMM//SSMM GMGMMM//SSMM
StStrraattuumm
RelRelaayy
RRRRCC RARANANAPP
RRRRCC RARANANAPP
SCSCCCPP SCSCCCPP
RLRLCC RLRLCC
M3M3 UUAA M3M3UUAA
MAMACC MAMACC
AcAccceessss
SCSCTTPP SCSCTTPP
StStrraattuumm
IPIP IPIP
PHPHYY PHPHYY
EEttherhernetnet EEttheherrnnetet
GMGMRR11--33GG IuIu--PPSS
MEMESS
GGMMRR11-3-3GG S SBBSSSS SGSGSNSN

Figure 6: Protocol architecture for control plane (Iu interface)
End-to-end architectures using the GMR-1 3G air interface with different core network interfaces are shown in figure 7.
A given operator may choose an individual architecture option (A, Gb, Iu-PS) or a combination thereof.
In this description, the term "GMR-1" is used to refer to attributes of the air interface and system that uses the
A-interface and/or the Gb-interface. Where a particular attribute is only applicable to A-interface or Gb-interface, it will
be referred to as GMR-1 (A mode) or GMR-1 (Gb mode), respectively. The term GMR-1 3G is used to refer to
attributes of the air interface and system that uses the Iu-PS interface, and will be referred to as GMR-1 3G (Iu mode).
If no interface is referenced the attribute is common to all interfaces.

A
interface
MSC
2G SBSS PSTN
Gs
interface
SGSN
2.5G SBSS
IP
(R97)
Web
Server
Gb
interface
SGSN
3G SBSS
MG
IP/IMS
W
(3G Rel 6/7))
PSTN
Iu-PS
interface SIP Server
SIP Server
Figure 7: End-to-end architectures
GMR-1 3G operates in Frequency Division Duplex (FDD) mode with RF channel bandwidths from 31,25 kHz up to
312,5 kHz. It provides finer spectrum granularity yielding an easier spectrum sharing among different systems.
GMR-1 3G provides a wide range of bearer services from 1,2 kbit/s up to 590 kbit/s. High-quality telecommunication
services can be supported including voice quality telephony and data services in a global coverage satellite
environment.
ETSI
GMR-1 3G 41.202 15 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
The implementation of efficient multicast is shown in figure 8. Terminals use Internet Group Management
Protocol (IGMPv2) (see RFC 2236 [i.1]) to join multicast sessions. The core network functions as defined in 3GPP
specifications. The SBSS merges the multiple streams onto a single multicast TFI stream per beam. Details are provided
in TS 144 118 [15] and TS 101 376-4-12 [12].
The implementation of efficient multicast is shown in figure 8. Terminals use Internet Group Management Protocol
(IGMPv2) (see RFC 2236 [i.1]) to join multicast sessions.
IGMPv2
encapsulated in
PIM-SM
IGMPv2
Unicast UDP/IP
Multicast tree
encapsulated in
IGMPv2 encapsulated in
construction
Unicast UDP/IP
Joins GTP+UDP+IP
Mcast
RAN SGSN GGSN MCG Content
Server
Figure 8: Efficient multicast implementation
An example of flexible beam coverage support is shown in figure 9. GMR-1 3G is deployed in systems which use a
variety of beam types in the same system. Figure 9 shows a regional beam overlay, a spot beam overlay and flexible
traffic-only beams superimposed on the same coverage area. In this example, regional beams might be large with
relatively low G/T and EIRP properties suitable for support of aeronautical terminals with high-gain antennas. Spot
beam might be very small with much higher G/T and EIRP designed to support high capacity and very small handheld
terminals with electrically small, low gain antennas. Traffic-only beams might be stationary or steerable and configured
to support spot traffic needs. With the advances in satellite/ground technology including ground based beam formers,
steerable antennas and array architectures, the GMR-1 3G air interface does not constrain satellite or system design.
ETSI
GMR-1 3G 41.202 16 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
Traffic only
Regional Beam
beams
Overlay
Spot Beam
Overlay
Figure 9: Example of a flexible satellite beam architecture
5 Description of the air interface
5.1 Frame structure
See TS 101 376-5-2 [6] and TS 101 376-5-7 [11] for more details.
GMR-1 uses Frequency Division Duplex (FDD) of the forward and return links, with time division multiplex (TDM) on
the forward link and Time Division Multiple Access (TDMA) on the return link.
The air interface frame structure is shown in figure 10. The same frame structure is used on both the forward link and
the return link: in this description all references to "TDMA Frames" apply equally to TDM frames on the forward link
and TDMA frames on the return link.
The timeslots within a TDMA frame are numbered from 0 to 23 and a particular timeslot is referred to by its Timeslot
Number (TN). TDMA frames are numbered by a Frame Number (FN). The frame number is cyclic and has a range of
0 to FN_MAX = (16 × 4 × 4 896) - 1 = 313 343. The frame number is incremented at the end of each TDMA frame.
The complete cycle of TDMA frame numbers from 0 to FN_MAX is defined as a hyperframe. Other combinations of
frames include:
• Multiframes: A multiframe consists of 16 TDMA frames. Multiframes are aligned so that the FN of the first
frame in a multiframe, modulo 16, is always 0.
• Superframes: A superframe consists of four multiframes. Superframes are aligned so that the FN of the first
frame in a superframe, modulo 64, is always 0.
ETSI
GMR-1 3G 41.202 17 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
• System information cycle: The system information cycle has the same duration as a superframe. However,
the first frame of the system information cycle is delayed an integer number of frames (0 to 15) from the start
of a superframe. The actual delay is intentionally varied from spot beam to spot beam to reduce the satellite's
peak power requirements. The FCCH and BCCH are used to achieve system information cycle
synchronization at the MES.
1 hyperframe = 4 896 superframes = 19 584 multiframes = 313 344 TDMA frames (3h 28mn 53 s 760ms)

0 1 2 3 4892 4893 4894 4895
1 superframe = 4 multiframes = 64 TDMA frames (2,56 s)
0 1 2 3
1 multiframe = 16 TDMA frames (640 ms)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 TDMA frame = 24 timeslots (40 ms)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
1 timeslot = 78 bit durations (5/3 ms)
(1 bit duration = 5/234 ms)
Figure 10: Frame structure
5.2 Channels
See TS 101 376-5-2 [6] for more details.
The radio subsystem is required to support a certain number of logical channels that can be separated into two overall
categories.
• Traffic Channels (TCHs);
• Control Channels (CCHs).
5.2.1 Traffic channels
Circuit switched or A-mode traffic channels include those listed in table 1. These traffic channels are bidirectional.
Table 1: Circuit switched Traffic Channels
Gross data
Channel type User information capability Modulation Channel coding
transmission rate
TCH3 Encoded speech 5,85 kbit/s π /4 CQPSK Convolutional
Code
TCH6 User data: 4,8 kbit/s 11,70 kbit/s Convolutional
π /4 CQPSK
Fax: 2 kbit/s; 4 kbit/s or Code
4,8 kbit/s
TCH9 User data: 9,6 kbit/s 17,55 kbit/s π /4 CQPSK Convolutional
Fax: 2 kbit/s; 4 kbit/s; Code
4,8 kbit/s or 9,6 kbit/s
ETSI
GMR-1 3G 41.202 18 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
Packet channels are defined which provide data rates between 8,8 kbps and 587,2 kbps.
A packet data traffic channel (PDTCH) corresponds to the resource allocated to a single MES on one physical channel
for user data transmission. Different logical channels may be dynamically multiplexed on to the same PDTCH. The
PDTCH uses π/2 BPSK, π/4 QPSK, 16 APSK, or 32 APSK modulation. All packet data traffic channels are
unidirectional, either uplink (PDTCH/U), for a mobile-originated packet transfer or downlink (PDTCH/D) for a
mobile-terminated packet transfer.
PDTCHs are used to carry packet data traffic in either Gb or Iu mode. Those applicable to Gb mode are listed in table 2
and those applicable to Iu mode are listed in table 3. Different PDTCHs are defined by the suffix (m, n) where m
indicates the bandwidth of the physical channel in which the PDTCH is mapped, m × 31,25 kHz, and n defines the
number of timeslots allocated to this physical channel. Tables 2 and 3 summarize different types of packet traffic data
channels, PDTCH (m, 3), (m = 1, 4, 5 and 10), where the burst duration is 5 ms , PDTCH (m, 6), (m = 1, 2), where the
burst duration is 10 ms, and PDTCH (m, 12), (m = 5), where the burst duration is 20 ms.
A Dedicated Traffic Channel (DTCH) is used to carry user traffic when a dedicated channel (DCH) is allocated to the
terminal in packet dedicated mode. A DTCH is unidirectional. DTCH/U is used for the uplink and a DTCH/D is used
for the downlink. A DTCH may support either 2,45 kbps or 4,0 kbps encoded speech. Table 3 summarizes different
types of packet traffic data channels, DTCH (m, 3), (m = 1, 4, 5 and 10), where the burst duration is 5 ms,
DTCH (m, 6), (m = 1, 2), where the burst duration is 10 ms, and DTCH (m, 8), (m = 1), where the burst duration is
13,333 ms.
Table 2: Packet Data Traffic Channels (PDTCH and PDTCH2)
Channels Direction Trans- Channel Modulation Trans- Peak payload Peak payload
(U: Uplink, mission Coding mission transmission transmission
D: symbol rate bandwidth rate (without rate (with
Downlink) (ksps) (kHz) CRC) CRC)
(kbps) (kbps)
PDTCH (4,3) U/D 93,6 Conv π/4-QPSK 125,0 113,6 116,8
PDTCH (5,3) U/D 117,0 Conv 156,25 145,6 148,8
π/4-QPSK
PDTCH (1,6) U/D 23,4 Conv π/4-QPSK 31,25 27,2 28,8
PDTCH (2,6) D/D 46,8 Conv 62,5 62,4 64,0
π/4-QPSK
PDTCH2 (5,12) D 117,0 LDPC π/4-QPSK 156,25 199,2 199,6
PDTCH2 (5,12) D 117,0 LDPC 16-APSK 156,25 354,8 355,2
PDTCH2 (5,12) D 117,0 LDPC 32-APSK 156,25 443,6 444,0
PDTCH2 (5,12) U 117,0 LDPC 156,25 199,2 199,6
π/4-QPSK
PDTCH2 (5,12) U 117,0 LDPC 16-APSK 156,25 399,2 399,6
PDTCH2 (5,3) U/D 117,0 LDPC 156,25 169,6 171,2
π/4-QPSK
PDTCH2 (5,3) U/D 117,0 LDPC 16-APSK 156,25 342,4 344,0
PDTCH2 (5,3) U/D 117,0 LDPC 32-APSK 156,25 380,8 382,4

ETSI
GMR-1 3G 41.202 19 ETSI TS 101 376-1-3 V3.3.1 (2012-12)
Table 3: Dedicated Traffic Channels (DTCH) and Packet Data Traffic Channels (PDTCH3)
Channels Direction Trans- Channel Modulation Trans- Peak payload Peak payload
(U: Uplink, mission Coding mission transmission transmission
D: symbol rate bandwidth rate (without rate (with
Downlink) (ksps) (kHz) CRC) CRC)
(kbps) (kbps)
DTCH (1,3) U/D 23,4 Conv 31,25 28,8 32,0
π/4-QPSK
DTCH (1,6) U/D 23,4 Conv π/2-BPSK 31,25 14,4 16,0
DTCH (1,6) U/D 23,4 Conv 31,25 8,8 10,4
π/4-QPSK
DTCH (1,8) U/D 23,4 Conv π/2-BPSK 31,25 10,8 12,0
PDTCH3(1,6) U/D 23,4 Conv. 31,25 27,2 28,8
π/4-QPSK
PDTCH3(2,6) U/D 46,8 Conv. π/4-QPSK 62,5 62,4 64,0
PDTCH3 (2,6) U/D 46,8 Turbo 62,5 62,4 64,0
π/4-QPSK
PDTCH3 (5,3) U/D 117,0 Turbo π/4-QPSK 156,25 156,8 160,0
PDTCH3 (5,3) D 117,0 Turbo 16-APSK 156,25 252,8 256,0
PDTCH3 (5,12) U/D 117,0 Turbo 156,25
π/4-QPSK 185,2 186,0
PDTCH3(5,12) U/D 117,0 Turbo 16-APSK 156,25 257,6 259,2
PDTCH3 (5,12) D 117,0 Turbo 16-APSK 156,25 294,4 296,0
PDTCH3 (10,3) D 234,0 Turbo 312,50
π/4-QPSK 344,0 347,2
PDTCH3 (10,3) D 234,0 Turbo 16-APSK 312,50 587,2 590,4

A complete listof supported modulation and coding schemes is found in TS 101 376-4-12 [12].
5.2.1.1 Cell Broadcast Channels
Traffic can be broadcast on a per spot beam basis using the Cell Broadcast CHannel (CBCH). This channel is downlink
only and used to broadcast Short Message Service Cell Broadcast (SMSCB) information to MESs. When the FCCH is
used the CBCH is broadcast using a DC6 burst structure and when the FCCH3 is used the CBCH is broadcast using a
DC12 burst structure.
5.2.2 PUI and PRI
A MAC/RLC block consists of PUI (Public User Information) and PRI (Private User Information) as shown in
figure 11. Downlink blocks may include an extended PUI which contains an uplink allocation mapping or
ULMAP. This field allows multiple uplink assignments to different MES using the same downlink burst.
See TS 101 376-4-12 [12] and TS 101 376-5-2 [6] for more detaile
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