ETSI TS 102 744-3-4 V1.1.1 (2015-10)

ETSI TS 102 744-3-4 V1.1.1 (2015-10)






TECHNICAL SPECIFICATION
Satellite Earth Stations and Systems (SES);
Family SL Satellite Radio Interface (Release 1);
Part 3: Control Plane and User Plane Specifications;
Sub-part 4: Bearer Connection Layer Operation

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2 ETSI TS 102 744-3-4 V1.1.1 (2015-10)



Reference
DTS/SES-00299-3-4
Keywords
3GPP, GPRS, GSM, GSO, interface, MSS, radio,
satellite, TDM, TDMA, UMTS
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3 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Symbols and abbreviations . 7
3.1 Symbols . 7
3.2 Abbreviations . 7
4 General Architecture . 7
4.0 Overview . 7
4.1 Bearer Connection Layer Entities . 8
4.1.0 General . 8
4.1.1 Bearer Connection Manager (BCnM) . 9
4.1.2 Acknowledged Mode Data Handler (AM_DH) . 10
4.1.3 Transparent Mode Data Handler (TM_DH) . 10
4.1.4 Numbered Frame Data Handler (NUM_DH) . 10
4.1.5 Common Signalling Data Handler (COM_DH) . 10
4.2 Interfaces to Upper Layers . 10
4.2.1 User Plane Interfaces . 10
4.2.1.0 General . 10
4.2.1.1 Acknowledged Mode (AM)-SAP Primitives and Parameters . 11
4.2.1.2 Transparent Mode (TM) SAP Primitives and Parameters . 11
4.2.1.3 Unacknowledged Mode (UM) SAP Primitives and Parameters. 12
4.2.2 Control Plane Interfaces . 12
4.2.2.0 General . 12
4.2.2.1 CBCn-SAP Primitives and Parameters . 12
4.2.2.2 COM-SAP Primitives and Parameters . 15
4.3 Interfaces to the Lower Layer . 15
5 Bearer Connection Operations . 16
5.0 General . 16
5.1 Bearer Connection Manager . 16
5.2 Quality of Service (QoS) Control Function . 16
5.3 Acknowledged Mode Operation . 17
5.3.0 General . 17
5.3.1 AM_DH Architecture . 17
5.3.1.0 Overview . 17
5.3.1.1 Transmit Path Processing . 18
5.3.1.2 Receive Path Processing . 19
5.3.1.3 AM_DH Control Unit . 19
5.3.1.4 Transmit Path Processing in the Suspended State (UESS AM_DH only) . 20
5.3.2 The ARQ Mechanism . 20
5.3.3 Data Packet Structures . 21
5.3.3.0 General . 21
5.3.3.1 Definition of the I-Frame . 21
5.3.3.2 Definition of the RR-Frame . 21
5.3.3.3 Definition of the SREJ-Frame . 22
5.3.3.4 Definition of the Sub-Segment Frame. 22
5.3.4 Sending I-Frames . 22
5.3.5 Receiving I-Frames . 23
5.3.6 Polling Mechanism . 23
5.3.6.0 General . 23
ETSI

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4 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
5.3.6.1 ARQ Timer . 24
5.3.6.2 Sending a Poll . 24
5.3.6.3 Response to a Poll . 25
5.3.6.4 Response to a Poll Response . 25
5.3.7 Transmit Behaviour . 26
5.3.7.0 General . 26
5.3.7.1 Support for final-seg-retx-allowed (fsr) Mode . 29
5.3.8 Receive Behaviour . 29
5.3.8.0 General . 29
5.3.8.1 RNC Support for final-seg-retx-allowed ("fsr") Mode . 30
5.3.9 Tx and Rx Window Size Control . 32
5.3.10 Acknowledged Mode Timers . 33
5.3.11 Example Retransmission Sequence . 34
5.4 Transparent Mode Operations . 36
5.4.0 General . 36
5.4.1 Transparent Mode Timers . 37
5.5 Un-Acknowledged Mode Operations . 38
5.5.0 General . 38
5.5.1 Un-Acknowledged Mode Timers . 39
5.6 Common Signalling Data Handler Operation . 39
5.7 Ciphering Operation . 39
5.7.0 General . 39
5.7.1 Input Parameters to the Ciphering Algorithm . 40
5.7.1.0 General . 40
5.7.1.1 CK . 40
5.7.1.2 COUNT-C . 40
5.7.1.3 TBCNID and BCNID . 41
5.7.1.4 DIRECTION . 41
5.7.1.5 LENGTH . 41
5.7.2 Initialization of Keystream Generator. 41
5.7.3 Maintenance of COUNT-C . 41
5.7.4 MBMS Connections . 42
5.8 Handover Operations . 42
History . 43

ETSI

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5 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
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 3, sub-part 4 of a multi-part deliverable. Full details of the entire series can be found in
ETSI TS 102 744-1-1 [i.1].
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
This multi-part deliverable (Release 1) defines a satellite radio interface that provides UMTS services to users of mobile
terminals via geostationary (GEO) satellites in the frequency range 1 518,000 MHz to 1 559,000 MHz (downlink) and
1 626,500 MHz to 1 660,500 MHz and 1 668,000 MHz to 1 675,000 MHz (uplink).
ETSI

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6 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
1 Scope
The present document defines the Bearer Connection Layer operation of the Family SL satellite radio interface between
the Radio Network Controller (RNC) and the User Equipment (UE) used in the satellite network. The Bearer
Connection Layer (BCn) peer-to-peer interface is described in ETSI TS 102 744-3-3 [9].
2 References
2.1 Normative 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.
The following referenced documents are necessary for the application of the present document.
[1] ETSI TS 125 322: "Universal Mobile Telecommunications System (UMTS); Radio Link Control
(RLC) protocol specification (3GPP TS 25.322 Release 4)".
[2] ETSI TS 133 102: "Universal Mobile Telecommunications System (UMTS); 3G security; Security
architecture (3GPP TS 33.102 Release 4)".
[3] ETSI TS 133 105: "Universal Mobile Telecommunications System (UMTS); Cryptographic
algorithm requirements (3GPP TS 33.105 Release 4)".
[4] ETSI TS 135 201: "Universal Mobile Telecommunications System (UMTS); Specification of the
3GPP confidentiality and integrity algorithms; Document 1: f8 and f9 specifications
(3GPP TS 35.201 Release 4)".
[5] ETSI TS 102 744-1-3: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 1: General Specifications; Sub-part 3: Satellite Radio Interface
Overview".
[6] ETSI TS 102 744-1-4: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 1: General Specifications; Sub-part 4: Applicable External
Specifications, Symbols and Abbreviations".
[7] ETSI TS 102 744-3-1: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 1: Bearer
Control Layer Interface".
[8] ETSI TS 102 744-3-2: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 2: Bearer
Control Layer Operation".
[9] ETSI TS 102 744-3-3: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 3: Bearer
Connection Layer Interface".
[10] ETSI TS 102 744-3-5: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 5: Adaptation
Layer Interface".
[11] ETSI TS 102 744-3-6: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 6: Adaptation
Layer Operation".
ETSI

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7 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
2.2 Informative 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.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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 102 744-1-1: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 1: General Specifications; Sub-part 1: Services and Architectures".
3 Symbols and abbreviations
3.1 Symbols
For the purposes of the present document, the symbols given in ETSI TS 102 744-1-4 [6], clause 3 apply.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI TS 102 744-1-4 [6], clause 3 apply.
4 General Architecture
4.0 Overview
The function of the satellite radio interface Bearer Connection Layer (BCn) is to provide a number of different data
transport services to upper layers. Figure 4.1 illustrates the position of the Bearer Connection Layer within the Family
SL air interface protocol stack. An overview of the radio interface layering and relationship to the Bearer Control Layer
is provided in ETSI TS 102 744-1-3 [5], clause 4 and ETSI TS 102 744-3-3 [9], clause 4. An overview of the Bearer
Connection Layer operation is provided in ETSI TS 102 744-1-3 [5], clause 6.

Figure 4.1: Bearer Connection Layer Position in Protocol Stack (Control Plane Illustrated)
ETSI

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8 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
The Bearer Connection Layer is generic to the radio interface and is responsible for the following:
• Queuing;
• QoS Policing;
• QoS Monitoring;
• Segmentation and Re-assembly;
• Ciphering; and
• Selectable ARQ.
The data transport services provided by the Bearer Connection Layer are used to carry signalling and data PDUs across
the satellite radio interface. Three main data transport modes are supported:
• Acknowledged Mode (AM)
• Transparent Mode (TM)
• Unacknowledged (Numbered Frame) Mode (UM)
These are provided to the upper layers via a number of different service access points (SAP). The control plane and user
plane architecture of the Bearer Connection Layer is illustrated in Figure 4.2 and Figure 4.3 respectively.
The following clauses describe the Bearer Connection Layer SAP primitives for the upper interface to the Adaptation
Layer. The SAP primitives for the lower interface to the Bearer Control Layer are described in ETSI
TS 102 744-3-2 [8].
4.1 Bearer Connection Layer Entities
4.1.0 General
The Bearer Connection Layer consists of a Bearer Connection Manager and instances of one of four possible data
handlers (COM_DH, AM_DH, NUM_DH and TM_DH) with their associated Service Access Points (SAPs).
The Control Plane of each UE consists of an AM_DH for the UE Specific Signalling connection, a COM_DH for
managing the Common Signalling connection and a Bearer Connection Manager. On the RNC side, the Control Plane
consists of multiple sets of AM_DH and Bearer Connection Manager entities, one for each UE registered. It also has a
COM_DH for each of the Primary Shared Access Bearer.
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9 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
Adaptation Layer -
Control Plane
CBCn-
AM-SAP COM-SAP
SAP
Bearer
AM_DH Connection COM_DH
Manager
Bearer Connection
Layer - Control
BCt-DATA-
Plane BCt-COM-
STATUS-SAP
SAP
SAP
Bearer Control Layer

Figure 4.2: Bearer Connection Layer - Control Plane
The User Plane of each UE consists of a Bearer Connection Manager and one data handler (either TM_DH, NUM_DH
or AM_DH) for each data connection that is set up. On the RNC side, the User Plane consists of multiple sets of these
entities, one for each UE registered.
Adaptation Layer - User Plane
TM-SAP UM-SAP AM-SAP
Bearer
Connection
Layer
TM_DH NUM_DH AM_DH
Bearer
Connection
Manager
STATUS-
BCt-UCDATA- BCt-DATA-
SAP
SAP SAP
Bearer Control Layer

Figure 4.3: Bearer Connection Layer - User Plane
4.1.1 Bearer Connection Manager (BCnM)
The Bearer Connection Manager (BCnM) provides bearer connection management services to the Adaptation Layer via
the CBCn-SAP. This includes the creation and removal of a particular connection, and the setting of its QoS parameters.
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10 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
Four data handlers are supported by the Bearer Connection Layer:
• Acknowledged Mode Data Handler (AM_DH)
• Transparent Mode Data Handler (TM_DH)
• Numbered Frame Data Handler (NUM_DH)
• Common Signalling Data Handler (COM_DH)
These shall be created by the BCnM based on the requests received from the Adaptation Layer.
4.1.2 Acknowledged Mode Data Handler (AM_DH)
The Acknowledged Mode Data Handler shall be created when a reliable delivery message transport is required e.g. for
packet data and signalling connections. In the control plane, it is used to transport UE Specific Signalling (UESS)
messages from the Adaptation Layer (AL). Note that the SIG-SAP as defined in the Adaptation Layer
(see ETSI TS 102 744-3-6 [11]) is an instance of the AM-SAP.
Reliable delivery of data is provided by the AM_DH using an ARQ mechanism. It can also guarantee the ordered
delivery of packets and provide ciphering of data packets. The ciphered data Protocol Data Unit (PDU) is sent to the
Bearer Control Layer via the BCt-DATA-SAP. Queue status in the AM_DH is reported to the Bearer Control Layer by
the BCnM via the STATUS-SAP.
4.1.3 Transparent Mode Data Handler (TM_DH)
The transparent mode data handler (TM_DH) is created when a transparent data link is requested. This is primarily used
to support circuit switched (CS) traffic. In transparent mode, no connection layer overhead is added to the data arriving
from the layer above.
Data coming from the higher layer via the TM-SAP is buffered by the TM_DH before forwarding to the Bearer Control
Layer. No ciphering is performed at the connection layer and the data is sent to the Bearer Control Layer via the BCt-
UCDATA-SAP. The size of the buffer in TM_DH is always reported to the Bearer Control Layer by the BCnM via the
STATUS-SAP.
4.1.4 Numbered Frame Data Handler (NUM_DH)
For Un-Acknowledged Mode data coming from the layer above via the UM-SAP, a Numbered Frame Data Handler
(NUM_DH) shall be used. The NUM_DH provides in-sequence delivery, segmentation and re-assembly, and ciphering
of data. However, packet delivery is not guaranteed. The ciphered data PDUs are sent to the Bearer Control Layer via
the BCt-DATA-SAP.
4.1.5 Common Signalling Data Handler (COM_DH)
The Common Signalling Data Handler exists only in the control plane of the Bearer Connection Layer. This handler
provides buffering for Common Signalling messages from the Adaptation Layer. It also supports the reporting of
STATUS information via the STATUS-SAP to the control layer. No Ciphering is required for Common Signalling
messages in the Connection Layer.
4.2 Interfaces to Upper Layers
4.2.1 User Plane Interfaces
4.2.1.0 General
Three SAPs (AM-SAP, UM-SAP and TM-SAP) are defined between the Bearer Connection Layer and the upper layers
in the user plane. Their definitions are based on [1]. The primitives and parameters used are summarized below.
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11 ETSI TS 102 744-3-4 V1.1.1 (2015-10)
4.2.1.1 Acknowledged Mode (AM)-SAP Primitives and Parameters
Three primitives are defined for the AM-SAP, as shown in Table 4.1.
Table 4.1: Primitives at the AM-SAP
Primitive Name Direction Paramete
...