ETSI TS 102 721-5 V1.2.1 (2013-08)

Satellite Earth Stations and Systems (SES); Air Interface for S-band Mobile Interactive Multimedia (S-MIM); Part 5: Protocol Specifications, Link Layer

RTS/SES-00337

General Information

• Status: Published
• Publication Date: 07-Aug-2013
• Technical Committee: SES SCN - Satellite Communications and Navigation
• Current Stage: 12 - Completion
• Due Date: 12-Aug-2013
• Completion Date: 08-Aug-2013
• Mandate: M/496

Standards Content (Sample)

Technical Specification
Satellite Earth Stations and Systems (SES);
Air Interface for S-band Mobile Interactive Multimedia (S-MIM);
Part 5: Protocol Specifications, Link Layer

2 ETSI TS 102 721-5 V1.2.1 (2013-08)

Reference
RTS/SES-00337
Keywords
MSS, satellite
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ETSI
3 ETSI TS 102 721-5 V1.2.1 (2013-08)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 8
4 General Description . 11
4.1 Forward Link . 11
4.1.1 Encryption Sub-layers. 12
4.1.2 Header Compression Sub-layer . 12
4.1.3 Encapsulation and Addressing sub-layers . 12
4.2 Return Link . 13
4.2.1 Asynchronous Access . 13
4.2.1.1 Header Compression Sub-layer . 13
4.2.1.2 Transmission Mode sub-layer . 13
4.2.1.3 Encapsulation and Addressing sub-layer . 14
4.2.1.4 Encryption sub-layer . 14
4.2.2 Synchronous Access . 14
4.2.2.1 Header Compression sub-layer . 15
4.2.2.2 Encapsulation and Addressing sub-layer . 15
4.2.2.3 Encryption sub-layer . 15
5 Header Compression . 15
5.1 Header Compression for Broadcast/Multicast Services . 17
5.2 Header Compression for Short Messages . 18
5.2.1 Context Identifier extension . 18
5.3 Header Compression for Bidirectional Services . 20
5.3.1 Feedback Messages. 21
5.3.1.1 Piggybacked or interspersed mode . 22
5.3.1.2 Dedicated channel mode . 23
5.3.2 Encapsulation . 23
5.3.2.1 Encapsulation with MPE . 23
5.3.2.2 Encapsulation with RLE . 24
5.3.3 ROHC parameters . 24
6 Encapsulation (Fragmentation & Reassembly) . 24
6.1 Forward Link Encapsulation . 25
6.2 Return Link Encapsulation . 26
6.2.1 Encapsulation for SSA Radio Interface . 28
6.2.2 Encapsulation for QS-CDMA radio interface . 28
6.2.2.1 DCH transport channel . 29
6.2.2.2 RACH transport channel . 29
7 MAC Layer Addressing . 29
7.1 Forward Link . 30
7.2 MPE MAC Address format . 30
7.3 Return Link . 31
7.3.1 QS-CDMA return link . 31
7.3.1.1 MAC Layer addressing for RACH . 31
7.3.1.2 MAC Layer addressing for QS-CDMA . 31
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4 ETSI TS 102 721-5 V1.2.1 (2013-08)
7.3.2 SSA return link . 31
8 Link Layer ARQ . 31
8.1 ARQ Mechanism at Terminal: Stop and Wait Cumulative ARQ . 33
9 Load control (LC) . 37
9.1 Internal Interfaces . 37
9.2 External Interfaces . 37
10 Call Admission Control/DAMA . 37
10.1 Capacity Allocation Initiated by the Terminal . 37
10.2 Capacity Allocation Initiated by the Hub . 38
10.3 Capacity Release Initiated by the Terminal . 39
10.4 Capacity Release Initiated by the Hub . 40
11 Security Mechanisms . 40
11.1 Security procedures . 42
11.1.1 Mutual authentication procedure . 42
11.1.1.1 Mutual Authentication procedure using IMSI over Satellite . 42
11.1.1.2 Mutual Authentication procedure using IMSI over CGC . 43
11.1.1.3 Mutual Authentication procedure using TMSI over Satellite . 44
11.1.1.4 Mutual Authentication procedure using TMSI over CGC . 44
11.1.2 TMSI renewal procedure . 45
11.1.2.1 TMSI renewal procedure over Sat . 46
11.1.2.2 TMSI renewal procedure over CGC . 46
11.1.3 Forward link security negotiation procedure . 46
11.1.3.1 Forward link security negotiation procedure over Sat . 47
11.1.3.2 Forward link security negotiation procedure over CGC . 47
11.2 IP Layer Security . 48
12 Mobility Management . 49
12.1 Location Management Protocol . 49
12.1.1 Terminal Location in the FWD Link . 50
12.1.2 Terminal Location in the RTN Link: Cell Selection Procedure . 50
12.1.2.1 Positioning Device-Disabled Terminals . 51
12.2 Handover Protocols for SS1/SS2 . 52
12.2.1 FWD link handover . 52
12.2.2 RTN Link Handover . 52
12.3 Handover Protocols for SS3 . 52
12.4 Roaming . 52
12.4.1 Scope of roaming in the S-MIM system . 52
12.4.2 The roaming procedure . 53
Annex A (informative): Recommendations for use of higher layer protocols. 55
A.1 IP Addressing . 55
A.1.1 Unique Local IPv6 address . 55
A.1.2 Global IPv6 address. 56
Annex B (informative): Recommendations for SS3 handover . 57
B.1 Forward Link Handover . 57
B.2 Return Link Handover . 57
B.2.1 Spot Selection Procedure . 57
B.2.2 Handover . 57
B.3 Network Layer (IP) Handover . 58
B.4 Link Layer Handover . 58
History . 59

ETSI
5 ETSI TS 102 721-5 V1.2.1 (2013-08)
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 present document is part 5 of a multi-part deliverable. Full details of the entire series can be found in part 1 [i.10].
Introduction
The S-MIM system specified herein is designed to provide:
• Interactive mobile broadcast services.
• Messaging services for handhelds and vehicular terminals, capable of serving millions of terminals due to a
novel optimized air-interface in the RTN link.
• Real-time emergency services such as voice and file transfer, mainly addressing institutional users
on-the-move such as fire brigades, civil protection, etc.
Inside the S-band, the 2 GHz MSS band is of particular interest for interactive multimedia, since it allows two-way
transmission. Typically, the DVB-SH standard [i.9] is applied for broadcast transmission; ETSI SDR [i.5] or
DVB-NGH [i.15] standards are other alternatives. Essential requirements under the R&TTE directive are covered by the
harmonized standard EN 302 574 [i.6], [i.7] and [i.8].
The technology applied has been developed in the framework of the ESA funded project "DENISE" (ESTEC/Contract
Number 22439/09/NL/US).
ETSI
6 ETSI TS 102 721-5 V1.2.1 (2013-08)
1 Scope
The present document specifies the S-MIM (S-band Mobile Interactive Multimedia) system in which a standardized
S-band satellite mobile broadcast system is complemented by the addition of a return channel.
The present document is part 5 of a multi-part deliverable and concerns aspects of the air interface for the S-band
Mobile Interactive Multimedia (S-MIM) system, and in particular it specifies the Link Layer protocols.
The other parts are listed in the foreword of part 1 [i.10].
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] ETSI EN 301 192: "Digital Video Broadcasting (DVB); DVB specification for data broadcasting".
[2] ETSI TS 102 721-3: "Satellite Earth Stations and Systems (SES); Air Interface for S-band Mobile
Interactive Multimedia (S-MIM); Part 3: Physical Layer Specification, Return Link Asynchronous
Access".
[3] ETSI TS 102 721-4: "Satellite Earth Stations and Systems (SES); Air Interface for S-band Mobile
Interactive Multimedia (S-MIM); Part 4: Physical Layer Specification, Return Link Synchronous
Access".
[4] ETSI TS 102 721-6: "Satellite Earth Stations and Systems (SES); Air Interface for S-band Mobile
Interactive Multimedia (S-MIM); Part 6: Protocol Specifications, System Signalling".
[5] ETSI TS 133 102 (V10.0.0): "Universal Mobile Telecommunications System (UMTS); LTE; 3G
security; Security architecture (3GPP TS 33.102 version 10.0.0 Release 10)".
[6] ETSI TS 133 105 (V10.0.0): "Universal Mobile Telecommunications System (UMTS); LTE;
Cryptographic algorithm requirements (3GPP TS 33.105 version 10.0.0 Release 10)".
[7] IETF RFC 2406: "IP Encapsulating Security Payload (ESP)".
[8] IETF RFC 2464: "Transmission of IPv6 Packets over Ethernet Networks".
[9] IETF RFC 3409: "Lower Layer Guidelines for Robust RTP/UDP/IP Header Compression".
[10] IETF RFC 4306: "Internet Key Exchange (IKEv2) Protocol".
[11] IETF RFC 4815: "RObust Header Compression (ROHC): Corrections and Clarifications to
RFC 3095".
[12] IEEE Std 802-2001 "IEEE Standard for Local and Metropolitan Area Networks: Overview and
Architecture".
[13] IETF Internet Draft 6LowPAN-hc-15: "Compression Format for IPv6 Datagrams in Low Power
and Lossy Networks (6LowPAN)".
ETSI
7 ETSI TS 102 721-5 V1.2.1 (2013-08)
[14] ETSI TS 102 606: "Digital Video Broadcasting (DVB); Generic Stream Encapsulation (GSE)
Protocol".
[15] ETSI TS 103 179: "Satellite Earth Stations and Systems (SES); Return Link Encapsulation
Protocol (RLE)".
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 102 611-1: "Digital Video Broadcasting (DVB); IP Datacast: Implementation Guidelines
for Mobility; Part 1: IP Datacast over DVB-H".
[i.2] ETSI TS 102 611-2: "Digital Video Broadcasting (DVB); IP Datacast: Implementation Guidelines
for Mobility; Part 2: IP Datacast over DVB-SH".
[i.3] ETSI TS 102 470-1: "Digital Video Broadcasting (DVB); IP Datacast: Program Specific
Information (PSI)/Service Information (SI); Part 1: IP Datacast over DVB-H".
[i.4] IANA: "Robust Header Compression (ROHC) Profile identifiers".
NOTE: Available at http://www.iana.org/assignments/rohc-pro-ids/.
[i.5] ETSI EN 302 550 (all parts and sub-parts): "Satellite Earth Stations and Systems (SES); Satellite
Digital Radio (SDR) Systems".
[i.6] ETSI EN 302 574-1: "Satellite Earth Stations and Systems (SES); Harmonized standard for
satellite earth stations for MSS operating in the 1 980 MHz to 2 010 MHz (earth-to-space) and
2 170 MHz to 2 200 MHz (space-to-earth) frequency bands; Part 1: Complementary Ground
Component (CGC) for wideband systems: Harmonized EN covering the essential requirements of
article 3.2 of the R&TTE Directive".
[i.7] ETSI EN 302 574-2: "Satellite Earth Stations and Systems (SES); Harmonized standard for
satellite earth stations for MSS operating in the 1 980 MHz to 2 010 MHz (earth-to-space) and
2 170 MHz to 2 200 MHz (space-to-earth) frequency bands; Part 2: User Equipment (UE) for
wideband systems: Harmonized EN covering the essential requirements of article 3.2 of the
R&TTE Directive".
[i.8] ETSI EN 302 574-3: "Satellite Earth Stations and Systems (SES); Harmonized standard for
satellite earth stations for MSS operating in the 1 980 MHz to 2 010 MHz (earth-to-space) and
2 170 MHz to 2 200 MHz (space-to-earth) frequency bands; Part 3: User Equipment (UE) for
narrowband systems: Harmonized EN covering the essential requirements of article 3.2 of the
R&TTE Directive".
[i.9] ETSI TS 102 585: "Digital Video Broadcasting (DVB); System Specifications for Satellite
services to Handheld devices (SH) below 3 GHz".
[i.10] ETSI TS 102 721-1: "Satellite Earth Stations and Systems (SES); Air Interface for S-band Mobile
Interactive Multimedia (S-MIM); Part 1: General System Architecture and Configurations".
[i.11] IETF RFC 4193: "Unique Local IPv6 Unicast Addresses".
[i.12] IETF RFC 2462: "IPv6 Stateless Address Autoconfiguration".
[i.13] IETF RFC 3095: "RObust Header Compression (ROHC): Framework and four profiles: RTP,
UDP, ESP, and uncompressed".
[i.14] IETF RFC 6282: "Compression Format for IPv6 Datagrams over IEEE 802.15.4-Based
Networks".
[i.15] DVB BlueBook A160: "Next Generation broadcasting system to Handheld, physical layer
specification (DVB-NGH)".
ETSI
8 ETSI TS 102 721-5 V1.2.1 (2013-08)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
2 GHz MSS band: 1 980 MHz to 2 010 MHz (earth-to-space) and 2 170 MHz to 2 200 MHz (space-to-earth) frequency
bands
NOTE: These paired bands are assigned to MSS.
architecture: abstract representation of a communications system
NOTE: Three complementary types of architecture are defined:
� Functional Architecture: the discrete functional elements of the system and the associated logical
interfaces.
� Network Architecture: the discrete physical (network) elements of the system and the associated
physical interfaces.
� Protocol Architecture: the protocol stacks involved in the operation of the system and the
associated peering relationships.
collector: terrestrial components that "collect" return link transmissions from terminals and forward them towards the
ground segment
control plane: plane that has a layered structure and performs the call control and connection control functions; it deals
with the signalling necessary to set up, supervise and release calls and connections
flow (of IP packets): traffic associated with a given connection-oriented, or connectionless, packet sequence having the
same 5-tuple of source address, destination address, Source Port, Destination Port, and Protocol type
management plane: plane that provides two types of functions, namely layer management and plane management
functions:
• Plane management functions: performs management functions related to a system as a whole and provides
co-ordination between all the planes. Plane management has no layered structure.
• Layer Management functions: performs management functions (e.g. meta-signalling) relating to resources
and parameters residing in its protocol entities.
repeater: terrestrial components that (mainly) repeat the satellite signal in the forward link
S-band: equivalent to 2 GHz MSS band
user plane: plane that has a layered structure and provides user information transfer, along with associated controls
(e.g. flow control, recovery from errors, etc.)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
3G Third generation mobile services,
3GPP Third Generation Partnership Project
ACK Acknowledgement
ALPDU Addressed Link Protocol Data Unit
ARQ Automatic Repeat reQuest
AuC Authentication Centre
AUTN Authentication Token
BCC Bidirectional Compressed Channel
Bslbf bit string left bit first
ETSI
9 ETSI TS 102 721-5 V1.2.1 (2013-08)
CAC Call Admission Control
CCITT Comité Consultatif International Téléphonique et Télégraphique
CD Compact Disk
CDMA Code Division Multiple Access
CGC Complementary Ground Component
CID Context Identifier
CK Encryption Key
CoS Class of Service
CRC Cyclic Redundancy Check
DAC Destination Address Compression
DAM Destination Address Mode
DAMA Dynamic Assignment Multiple Access
DCH Dedicated Channel
DCI Destination Context Identifier
DHCP Dynamic Host Configuration Protocol
DoS Denial of Service
DVB-H Digital Video Broadcasting, services to Handhelds
DVB-SH Digital Video Broadcasting, Satellites services to Handhelds
DVB-SHrt DVB-SH with real time features
EC Encrypted Channel
ESP Encapsulated Security Payload
E-SSA Enhanced Spread Spectrum Aloha
ETSI European Telecommunication Standards Institute
FO First-Order
FPDU Frame PDU
FWD Forward
GHz Giga Hertz
GNSS Global Navigation Satellite System
GPS Global Positioning System
GSE Generic Stream Encapsulation
HLIM Hop Limit
HLR Home Location Register
HNO Home Network Operator
IANA Internet Assigned Numbers Authority
ID Identifier
IETF Internet Engineering Task Force
IK Integrity Key
IKE Internet Key Exchange
IMSI International Mobile Subscriber Identity
IP Internet Protocol
IPSec IP Security
IPv4 Internet Protocol version 4
IPv6 Internet Protocol version 6
IR Initialization and Refresh state
IS Interface Satellite
L2 Layer 2
LAI Local Area Identifier
LAN Local Area Network
LC Load Control
LLC/SNAP Logical Link Control/Sub-Network Access Protocol
MAC Medium Access Control
MCC Mobile Country Code
MNC Mobile Network Code
MPE Multiprotocol Encapsulation
MPEG Moving Pictures Experts Group
MPEG-TS MPEG Transport Stream
MPE-IFEC MPE Inter-burst FEC
MSB Most Significant Bit
MSN Mobile Subscriber Number
MSS Mobile Satellite Service
NAT Network Address Translation
NCC Network Control Centre
ETSI
10 ETSI TS 102 721-5 V1.2.1 (2013-08)
nCC Non-Compressed Channel
NEC Non-Encrypted Channel
NH Next Header
NRT Non-Real Time
OSPF Open Shortest Path First
PCCH Physical Control Channel
PCH Physical Channel
PDCH Physical Data Channel
PDU Protocol Data Unit
PHY Physical Layer
PID Packet Identifier
PLR Packet Loss Ratio
PPDU Payload-adapted Protocol Data Unit
PSI/SI Program Specific Information/Service Information
PSTN Public Switched Telephone Network
QS-CDMA Quasi Synchronous CDMA
RACH Random Access Channel
RAND Random Number
RES Response
RFC Request for Comment
RLE Return Link Encapsulation
RM Resource Management
ROHC Robust Header Compression
RTN Return (link)
RTP Real-Time Transport Protocol
SA Security Association
SAC Source Address Compression
SAT SSA Access Table
SCI Source Context Identifier
SDR Satellite Digital Radio
SDR Satellite Digital Radio
SDT SSA Dynamic Table
SEL Service Enabling Layer
SEP Service Enabling Platform
SFN Single Frequency Network
SIP Session Initiation Protocol
S-MIM S-band Mobile Interactive Multimedia
SMS Short Message Service
SS Subsystem
SS1 Service Segment 1
SS2 Service Segment 2
SS3 Service Segment 3
SSA Spread Spectrum Aloha
TCP Transmission Control Protocol
TF Traffic Class
TMSI Temporary Mobile Subscriber Identity
UACK Unequivocally Acknowledged Mode
UCC Unidirectional Compressed Channel
UDP User Datagram Protocol
ULA Unique Local addressing
UMTS Universal Mobile Telecommunications System
UsCC Unidirectional stateless Compressed Channel
USIM Universal Subscriber Identity Module
VLR Visitor Location Register
VoIP Voice over IP General Description
XRES Expected Response
ETSI
11 ETSI TS 102 721-5 V1.2.1 (2013-08)
4 General Description
The S-MIM Link Layer provides a number of functionalities that will allow transport of IP traffic of different types
(broadcast, messaging, bidirectional traffic) over the radio interfaces of the S-MIM system.
The Link Layer implements the following functions:
• Header Compression to reduce the overhead transmitted over the system
• Encapsulation to transport the higher layer packets over the air interfaces of the S-MIM system
• MAC Layer Addressing
• ARQ for reliable link layer transmission
• Load control
• Call Admission Control/DAMA
• Security mechanisms
• Mobility Management
The related protocols are specified in the present document.
4.1 Forward Link
The detailed protocol stack for the S-MIM link and physical layers for access to SS1, SS2 and SS3 in the Forward Link
is depicted in Figure 4.1.
USER PLANE CONTROL PLANE MANAGEMENT PLANE

/
P
t
s M
a
D
c
Subscriber Service
/
a
t
P
a Management Protection
D M
N
P
I
S
P
Network /
C
T Traffic
P /
Terminal
I
P
Monitoring
D Management
U
IPsec
Encryption (IPSEC) Authentication
EC NEC
Ctrl
C
L
R
Header
Compression
Header Compression
nCC UCC UsCC BCC
Mutual
Management
Authentication
r
Ctrl
e
y
MPE Encapsulation
a
Mobility
L MPE MPE-iFEC
k & Addressing
Management
n
i
LL
L
Authentication
C Ctrl
Content
A
Encryption (LL)
EC NEC
M
Management
MPEG-TS Encapsulation
Signalling Resource
MPEG-TS
& Addressing Management Management
Coding,
rt-DCH rt-CCH nrt-CCH nrt-BCH
Y Modulation &
H
P Transmission
rt-PCH
nrt-PCH
Figure 4.1: Detailed protocol stack for the Forward Link
ETSI
12 ETSI TS 102 721-5 V1.2.1 (2013-08)
4.1.1 Encryption Sub-layers
The encryption functions are split in two sublayers: at IP and at MAC layers to provide security in the access to the
S-MIM communications system. In practice, hub and terminals will negotiate at which level encryption is applied (this
will depend on the capabilities of the communication peers) and upon successful negotiation, encryption will be only
applied at the agreed level by both peers according to the most restrictive capability. Both Encryption sub-layers,
managed by the mutual authentication control function, provide two access services to the respective underlying
sub-layer:
• Encrypted Channel (EC): upper layer packets mapped into this access service will be transmitted encrypted.
• Non-Encrypted Channel (NEC): upper layer packets mapped into this access service will be transmitted not
encrypted.
4.1.2 Header Compression Sub-layer
The Header Compression sub-layer provides four access services (also called header compression channels) to the
higher layer:
• Non-Compressed Channel (nCC): IP packets accessing through this service will be transmitted with
uncompressed header. This header compression channel can be accessed by all applications and services in
FWD and RTN links.
• Unidirectional Compressed Channel (UCC): IP packets accessing through this service will be transmitted with
compressed header using the technique as specified in clause 5. This header compression channel can be
accessed by SS1 broadcast/multicast applications (streaming, datacast) and services in the FWD link.
• Unidirectional stateless Compressed Channel (UsCC): IP packets accessing through this service will be
transmitted with compressed header using the technique as specified in clause 5. This header compression
channel can be accessed by short message application services in the FWD link.
• Bidirectional Compressed Channel (BCC): IP packets accessing through this service will be transmitted with
compressed header using the technique as specified in clause 5. This header compression channel can be
accessed by real-time bidirectional services in the FWD.
For the user plane, all four access services can be used. For the control plane, most of the data is system signalling that
is generated below IP, and therefore header compression is not applicable. Signalling applied to support synchronization
of compression profiles in the Bidirectional Compressed Channel shall be transmitted with uncompressed header.
For the management plane, the higher layer signalling that deals with network and terminal management can access all
four access services of the Header Compression sub-layer.
4.1.3 Encapsulation and Addressing sub-layers
Encapsulation and addressing is split in two sub-layers, one at MPE level and another one at MPEG-TS level. This
splitting serves the possibility to insert MAC layer encryption in the Forward Link. These sub-layers shall provide the
following encapsulation services in the FWD link:
• MPE Encapsulation:
- MPE Encapsulation (mandatory)
- MPE-iFEC Encapsulation (optional, only compatible with DVB-SH)
• MPEG Encapsulation.
NOTE: MPE-iFEC is only compatible with NRT broadcast. Unicast traffic needs a MAC address in the MPE
header, which is incompatible with MPE-iFEC.
All planes (user, control and management) shall have access to the mandatory access services of this sub-layer.
In terms of addressing, broadcast, multicast and unicast addressing is supported in the S-MIM forward radio interface.
Different descriptors can be used for addressing as defined in [1].
ETSI
13 ETSI TS 102 721-5 V1.2.1 (2013-08)
4.2 Return Link
The SSA and QS-CDMA options are described separately below.
4.2.1 Asynchronous Access
This refers to the SSA option. The detailed protocol stack for the S-MIM link any physical layers for access to SS1, SS2
in the Asynchronous Return Link is depicted in Figure 4.2.
USER PLANE CONTROL PLANE MANAGEMENT PLANE

/
P
t
s M
a
D
c
Subscriber Service
/
a
t
P
a Management Protection
D M
N
P
I
S
P
Network /
C
T Traffic
/
P Terminal
I
P
Monitoring
D Management
U
Header
Header IPsec
nCC UsCC
Signalling
Compression Compression Authentication
Management
Control Control
C
L
R
ARQ
Mobility Mutual
r Transmission Management
Tr Mode ACK Mode uACK Mode
e
Management Authentication
y & Congestion
Mode
a
Control
L
Control
k
n
i
L
Encapsulation &
LL
RLE
Addressing Authentication
C
Control
A
M
Encryption (LL)
EC NEC
Modulation &
Y
RACH
H
Transmission
P
PCCH PDCH
Figure 4.2: Detailed protocol stack for the Asynchronous Return Link
4.2.1.1 Header Compression Sub-layer
The Header Compression sub-layer provides two access services to the IP layer:
• Non-Compressed Channel (nCC).
• Unidirectional stateless Compressed Channel (UsCC).
These are as defined in clause 4.1.2.
4.2.1.2 Transmission Mode sub-layer
The Transmission Mode sub-layer, managed by the ARQ Management and Load control function, offers three access
services to the Header Compression sub-layer:
• Transparent Mode (Tr Mode): PDUs mapped into this transmission mode will be transmitted without
expecting any link layer acknowledgements in the forward link.
• Acknowledged Mode (ACK Mode): PDUs mapped into this transmission mode will require a link layer
CRC-based acknowledgement in the forward link, as specified in clause 8.
ETSI
14 ETSI TS 102 721-5 V1.2.1 (2013-08)
• Unequivocally Acknowledged Mode (uACK Mode): PDUs mapped into this transmission mode will require a
link layer dedicated and uniquely addressed ACK message in the forward link as specified in clause 8.
4.2.1.3 Encapsulation and Addressing sub-layer
The Encapsulation sub-layer offers one access service to the Transmission Mode sub-layer:
• RLE: Return Link Encapsulation.
Hence, RLE is used to encapsulate higher layer packets and to insert the system specific MAC layer addressing. The
MAC layer addresses applied are specified in clause 7.
4.2.1.4 Encryption sub-layer
The encryption sub-layer, only in the link layer in the case of the return link, managed by the link layer authentication
control, provide two access services to the Encapsulation and Addressing sub-layer:
• Encrypted Channel (EC): upper layer packets mapped into this access service will be transmitted encrypted, as
specified in clause 11.
• Non-Encrypted Channel (NEC): upper layer packets mapped into this access service will be transmitted not
encrypted.
4.2.2 Synchronous Access
This refers to the QS-CDMA option. The detailed protocol stack for the S-MIM link any physical layers for access to
SS3, in the Synchronous Return Link is depicted in Figure 4.3.
USER PLANE CONTROL PLANE MANAGEMENT PLANE
n
o
e i
t t
i
a Subscriber Service
u
c
s i
l
Management Protection
p
P
I
p
A
P
C Network /
Traffic
T
P /
Terminal
I
P Monitoring
D Management
U
Header
C Header
L
nCC BCC Compression Signalling
R
Compression
Control Management
r
e
y
a
L CAC/DAMA
Encapsulation &
Mobility
k
RLE Management
n
i
Management
Addressing
L
C
A
M
LL Encryption
Encryption (LL)
EC NEC
Control
Modulation & Sync & Power
DCH
RACH
Y
H Control
Transmission
P
DMPDCH DMPCCH
PDRACH PCRACH DPDCH
Figure 4.3: Detailed protocol stack for the Synchronous Return Link
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15 ETSI TS 102 721-5 V1.2.1 (2013-08)
4.2.2.1 Header Compression sub-layer
The Header Compression sub-layer provides two access services (also called header compression channel) to the IP
layer:
• Non-Compressed Channel (nCC): IP packets accessing through this service will be transmitted with
uncompressed header. This header compression channel can be accessed by all applications and services in
FWD and RTN links.
• Bidirectional Compressed Channel (BCC): IP packets accessing through this service will be transmitted with
compressed header using the technique as specified in clause 5. This header compression channel can be
accessed by bidirectional services under SS3.
4.2.2.2 Encapsulation and Addressing sub-layer
The Encapsulation sub-layer offers one access service to the Transmission Mode sub-layer:
• RLE: Return Link Encapsulation.
Hence, RLE is used to encapsulate higher layer packets and to insert the system specific MAC layer addressing. The
MAC layer addresses applied are specified in clause 7.
4.2.2.3 Encryption sub-layer
The encryption sub-layer, only in the link layer in the case of the return link, managed by the link layer authentication
control, provide two access services to the Encapsulation and Addressing sub-layer:
• Encrypted Channel (EC): upper layer packets mapped into this access service will be transmitted encrypted, as
specified in clause 11.
• Non-Encrypted Channel (NEC): upper layer packets mapped into this access service will be transmitted not
encrypted.
5 Header Compression
The Header Compression sub-layer provides four access services (also called header compression channels in the
present document) to the IP layer, as can be observed in Figure 5.1 and Figure 5.2:
• Non-Compressed Channel (nCC): IP packets accessing through this service will be transmitted with
uncompressed header. This header compression channel can be accessed by all applications and services in
FWD and RTN links. The traffic going through the path of the NCC can be mapped in all air interfaces of the
FWD and RTN link of the S-MIM system.
• Unidirectional Compressed Channel (UCC): IP packets accessing through this service will be transmitted with
compressed header using an adaptation of ROHC in unidirectional mode that will be specified in the following
clauses. This header compression channel can be accessed by SS1 broadcast/multicast applications (streaming,
datacast) and services in the FWD link. The traffic going through the path of the UCC can be mapped in the
Non Real Time PCH of the FWD air interface.
• Unidirectional stateless Compressed Channel (UsCC): IP packets accessing through this service will be
transmitted with compressed header using an adaptation of the RFC 6282 [i.14] that will be specified in clause
5.2. This header compression channel can be accessed by short message application services in the FWD and
RTN links. The traffic going through the path of the UsCC can be mapped in the Real Time PCH or the Non
Real Time PCH of the FWD air interface and on the SSA air inte
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