ETSI TS 144 006 V13.0.0 (2016-01)

ETSI TS 1144 006 V13.0.0 (201616-01)

TECHNICAL SPECIFICATIONION
Digital cellular telecocommunications system (Phahase 2+);
Mobile Station - Base e Station System (MS - BSS)) interface; i
Data Linknk (DL) layer specification
(3GPP TS 44.0.006 version 13.0.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS
3GPP TS 44.006 version 13.0.0 Release 13 1 ETSI TS 144 006 V13.0.0 (2016-01)

Reference
RTS/TSGG-0244006vd00
Keywords
GSM
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ETSI
3GPP TS 44.006 version 13.0.0 Release 13 2 ETSI TS 144 006 V13.0.0 (2016-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
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server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
3GPP TS 44.006 version 13.0.0 Release 13 3 ETSI TS 144 006 V13.0.0 (2016-01)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 7
1 Scope . 8
2 References . 8
3 Abbreviations . 8
4 General . 9
4.1 Options . 9
5 Frame structure for peer-to-peer communication . 10
5.1 General . 10
5.2 Frame delimitation and fill bits . 12
5.3 Address field . 12
5.4 Control field . 13
5.5 Length indicator field . 13
5.5a Short L2 header type 1 . 13
5.6 Information field . 13
5.7 Transparency . 13
5.8 Format convention . 13
5.8.1 Numbering convention . 13
5.8.2 Order of bit transmission . 13
5.8.3 Field mapping convention . 13
6 Elements of procedures and formats of fields for Data Link Layer peer-to-peer communication . 14
6.1 General . 14
6.2 Address field format . 14
6.3 Address field variables . 15
6.3.1 Address field extension bit (EA) . 15
6.3.2 Command/response field bit (C/R) . 15
6.3.3 Service access point identifier (SAPI) . 15
6.4 Control field formats . 15
6.4.1 Information transfer format - I . 15
6.4.2 Supervisory format - S . 16
6.4.3 Unnumbered format - U . 16
6.4a Short L2 header type 1 . 16
6.5 Control field parameters and associated state variables . 16
6.5.1 Poll/Final bit . 16
6.5.2 Multiple frame operation - variables and sequence numbers . 17
6.5.2.1 Modulus . 17
6.5.2.2 Send state variable V(S) . 17
6.5.2.3 Acknowledge state variable V(A) . 17
6.5.2.4 Send sequence number N(S) . 17
6.5.2.5 Receive state variable V(R). 17
6.5.2.6 Receive sequence number N(R) . 17
6.5.2.7 Other parameters and variables . 18
6.5.3 Unacknowledged operation variables and parameters . 18
6.6 Length indicator field format. 18
6.7 Length indicator field variables . 18
6.7.1 Length indicator field extension bit (EL) . 18
6.7.2 More data bit (M) . 18
6.7.3 Length indicator (L) . 18
6.8 Commands and responses . 19
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6.8.1 Information (I) commands . 19
6.8.2 Set asynchronous balanced mode (SABM) command . 19
6.8.3 Disconnect (DISC) command . 20
6.8.4 Unnumbered information (UI) command . 20
6.8.5 Receive ready (RR) command/response . 20
6.8.6 Reject (REJ) command/response . 21
6.8.7 Receive not ready (RNR) command/response . 21
6.8.8 Unnumbered acknowledgement (UA) response . 21
6.8.9 Disconnected mode (DM) response . 21
7 Elements for layer-to-layer communication . 22
7.1 Definition of primitives and parameters . 22
7.1.1 Generic names . 22
7.1.1.1 DL-ESTABLISH . 22
7.1.1.2 DL-RELEASE . 22
7.1.1.3 DL-DATA . 22
7.1.1.4 DL-UNIT DATA . 22
7.1.1.5 DL-SUSPEND . 22
7.1.1.6 DL-RESUME . 22
7.1.1.7 DL-RECONNECT . 23
7.1.1.8 DL-RANDOM ACCESS . 23
7.1.1.9 MDL-RELEASE . 23
7.1.1.10 MDL-ERROR . 23
7.1.1.11 PH-DATA . 23
7.1.1.12 PH-RANDOM ACCESS . 23
7.1.1.13 PH-CONNECT . 23
7.1.1.14 PH-READY-TO-SEND . 23
7.1.1.15 PH-EMPT Y-FRAME . 23
7.1.2 Primitives types . 23
7.1.2.1 REQUEST . 24
7.1.2.2 INDICATION . 24
7.1.2.3 RESPONSE . 24
7.1.2.4 CONFIRM . 24
7.1.3 Parameter definition . 25
7.1.3.1 Message unit . 25
7.1.3.2 Channel type . 25
7.1.3.3 Service Access Point . 25
7.1.3.4 Release mode . 25
7.1.3.5 Error cause . 25
7.1.3.6 Establish mode . 26
7.1.3.7 L2 header type . 26
7.1.3.8 Priority . 26
7.2 Primitive procedures. 29
8 Definition of the peer-to-peer protocol LAPDm . 29
8.1 General . 29
8.2 General Protocol Procedures . 30
8.2.1 Unacknowledged information transfer . 30
8.2.2 Acknowledged multiple frame information transfer . 31
8.3 Procedures for unacknowledged information transfer . 31
8.3.1 General . 31
8.3.2 Transmission of unacknowledged information . 31
8.3.3 Receipt of unacknowledged information . 31
8.4 Procedures for establishment and release of multiple frame operation . 31
8.4.1 Establishment of multiple frame operation . 31
8.4.1.1 General . 31
8.4.1.2 Normal establishment procedures . 32
8.4.1.3 Procedure on expiry of timer T200: Normal establishment . 33
8.4.1.4 Contention resolution establishment procedure . 33
8.4.1.5 Procedure on expiry of timer T200: contention resolution (MS only) . 35
8.4.2 Information transfer . 35
8.4.2.1 General requirements . 35
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8.4.2.2 Error conditions . 35
8.4.2.3 Fill frames . 36
8.4.3 Suspension and resumption of multiple frame operation . 36
8.4.3.1 General . 36
8.4.3.2 Suspension . 37
8.4.3.3 Resumption . 37
8.4.3.3.1 Procedure after channel change . 37
8.4.3.3.2 Procedure after returning to the old channel (MS only) . 38
8.4.4 Termination of multiple frame operation . 38
8.4.4.1 General . 38
8.4.4.2 Normal release procedure . 38
8.4.4.3 Procedure on expiry of timer T200 for normal release . 39
8.4.4.4 Local end release procedure . 39
8.4.5 Idle state . 39
8.4.6 Collision of unnumbered commands and responses . 40
8.4.6.1 Identical transmitted and received commands . 40
8.4.6.2 Different transmitted and received commands . 40
8.4.6.3 Unsolicited DM response and SABM or DISC command . 40
8.5 Procedures for information transfer in multiple frame operation . 40
8.5.1 Transmitting I frames. 40
8.5.2 Receiving I frames . 41
8.5.2.1 P bit of the received I frame set to "1" . 41
8.5.2.2 P bit of the received I frame set to "0" . 41
8.5.3 Receiving acknowledgement . 42
8.5.3.1 On receipt of a valid I frame . 42
8.5.3.2 Receiving supervisory command frames with the P bit set to "1" . 42
8.5.4 Receiving REJ frames . 42
8.5.4.1 Receipt of a valid REJ frame. 42
8.5.4.2 Transmitting frames . 43
8.5.5 Receiving RNR frame . 43
8.5.6 Data link layer own receiver busy condition. 45
8.5.7 Waiting acknowledgement . 45
8.5.8 Preemption . 46
8.5.8.1 Sender Requirements . 46
8.5.8.2 Receiver Requirements . 46
8.6 Abnormal release and re-establishment of multiple frame operation . 46
8.6.1 Criteria for re-establishment . 46
8.6.2 Criteria for abnormal release . 46
8.6.3 Procedures for re-establishment . 47
8.6.4 Procedures for abnormal release . 47
8.7 Exception condition reporting and recovery for multiple frame operation . 47
8.7.1 N(S) sequence error . 47
8.7.2 Timer recovery . 48
8.7.3 Invalid frame condition . 48
8.7.4 N(R) sequence error . 48
8.8 List of system parameters . 49
8.8.1 Timer T200 . 49
8.8.1.1 For SAPI=0 and SAPI=3 . 49
8.8.1.2 For SAPIs other than 0 or 3 . 49
8.8.2 Maximum number of retransmissions (N200) . 49
8.8.2.1 For SAPI=0 and 3 . 49
8.8.2.2 For SAPIs other than 0 or 3 . 50
8.8.3 Maximum number of octets in an I, UI, SABM and UA frame partially or entirely available for the
information field (N201) . 50
8.8.4 Maximum number of outstanding I frames (k) . 50
8.8.5 Maximum number of octets in a Layer 3 message . 50
8.9 System performance requirements . 50
9 Special protocol operation on SAPI=0 and SAPI=3 . 51
10 Repeated Downlink FACCH . 52
10.1 General . 52
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10.2 The FACCH Repetition . 52
10.3 BSS requirements . 52
10.4 MS requirements . 52
11 Repeated SACCH . 53
11.1 General . 53
11.2 Procedure for Repeated SACCH on the downlink . 53
11.3 Procedure for Repeated SACCH on the uplink . 53
Annex A (normative): Random access procedures . 54
A.1 Description of the procedure . 54
A.1.1 Procedure in the MS . 54
A.1.2 Procedure in the BS . 54
A.2 Format . 54
Annex G (normative): Handling of frames with parameter errors in the address, control
and length indicator fields . 55
G.1 General . 55
G.2 Parameter errors in the address field . 55
G.2.1 Unallocated SAPI . 55
G.2.2 Wrong value of the C/R bit . 55
G.2.3 EA bit set to "0". 55
G.3 Parameter errors in the control field . 56
G.3.1 Supervisory frames . 56
G.3.2 Unnumbered frames . 56
G.4 Parameter errors in the length indicator field . 56
G.4.1 EL bit error . 56
G.4.2 Information frames . 56
G.4.3 Supervisory frames . 57
G.4.4 DISC and DM frames . 57
G.4.5 SABM UA and UI frames . 57
Annex C (informative): Change History . 58
History . 59

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Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
ETSI
3GPP TS 44.006 version 13.0.0 Release 13 8 ETSI TS 144 006 V13.0.0 (2016-01)
1 Scope
The present document defines a data link layer protocol to be used for signalling, and possibly also for other
applications, on the MS-BS interface.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TS 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 44.001: "Mobile Station - Base Station System (MS - BSS) Interface General Aspects
and Principles".
[3] 3GPP TS 44.003: "Mobile Station - Base Station System (MS - BSS) interface Channel structures
and access capabilities".
[4] 3GPP TS 44.004: "Layer 1 General requirements".
[5] 3GPP TS 44.005: "Data Link (DL) layer General aspects".
[6] 3GPP TS 24.007: "Mobile radio interface signalling layer 3; General aspects".
[7] 3GPP TS 44.018: "Mobile radio interface layer 3 specification; Radio Resource Control Protocol".
[8] 3GPP TS 24.010: "Mobile radio interface layer 3 Supplementary services specification; General
aspects".
[9] 3GPP TS 44.012: "Short Message Service Cell Broadcast (SMSCB) support on the mobile radio
interface".
[10] 3GPP TS 45.002: "Multiplexing and multiple access on the radio path".
[11] 3GPP TS 48.056: "Base Station Controller - Base Transceiver Station (BSC - BTS) interface;
Layer 2 specification".
[12] 3GPP TS 48.058: "Base Station Controller - Base Transceiver Station (BSC - BTS) interface;
Layer 3 specification".
[13] CCITT Recommendation Z.100: "Specification and description language (SDL)".
3 Abbreviations
Abbreviations used in the present document are listed in 3GPP TS 21.905.
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4 General
The present document describes the frame structure, elements of procedure, format of fields and procedures for the
proper operation of the Link Access Procedure on the Dm channel, LAPDm.
NOTE 1: The term Dm channel is used for convenience to designate the collection of all the various signalling
channels required in the GSM system. See also 3GPP TS 44.003.
The concepts, terminology, overview description of LAPDm functions and procedures, and the relationship with other
Technical Specifications are described in general terms in 3GPP TS 44.005.
The frame formats defined for LAPDm are based on those defined for LAPD. However, there are important differences
between LAPDm and LAPD, in particular with regard to frame delimitation methods and transparency mechanisms.
These differences are necessary for operation within the constraints set by the radio path.
LAPDm supports two modes of operation:
- unacknowledged operation using UI frames;
- acknowledged operation using the multiple frame procedure.
As a choice of implementation, the two modes of operation may be implemented independently of each other. This is
possible since there is no interactions between the two modes, other than queuing at the transmitter, even when they
coexist on the same physical channel. For BCCHs and CCCHs only the unacknowledged mode of operation needs to be
implemented.
LAPDm is used for information sent on the control channels BCCH, AGCH, NCH, PCH, FACCH, SACCH and
SDCCH as defined in 3GPP TS 44.003.
NOTE 2: AGCH, NCH and PCH are sometimes referred to by the collective name CCCH and FACCH, SACCH and
SDCCH are, similarly, referred to by the collective name DCCH.
LAPDm may also be used on other types of channel.
NOTE 3: As stated in 3GPP TS 44.005, the term "data link layer" is used in the main text of this Technical
Specification. However, mainly in figures and tables, the terms "layer 2" and "L2" are used as abbreviations.
Furthermore, in accordance with 3GPP TS 24.007 and 3GPP TS 44.018, the term "layer 3" is used to indicate the layer
above the data link layer.
This Technical Specification is organized as follows:
The frame structure for peer-to-peer communication is given in clause 5. The elements of procedure and formats of
fields are given in clause 6. The elements of layer-to-layer communication are contained in clause 7. The details of the
peer-to-peer procedures are given in clause 8. clause 6 summarizes the special protocol operations used mandatorily
with SAPI=0 and SAPI = 3.
The specification for the random access channel is contained in annex A, even though it is not a LAPDm function. The
present document is descriptive and does not constrain the implementation of the random access function. The
procedure is used for CHANNEL REQUEST on the RACH and HANDOVER ACCESS on the main DCCH.
(Annexes B to F are deleted).
Annex G gives an overview of actions taken on frames containing parameter errors.
4.1 Options
Support of short L2 header type 1 is an option in both the mobile station and the network; under certain conditions the
support is mandatory, as specified in other Specifications. A layer 2 protocol entity not implementing short L2 header
type 1 shall diagnose an E/A bit error and proceed as defined in annex G.2.3.
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5 Frame structure for peer-to-peer communication
5.1 General
All data link layer peer-to-peer exchanges are in frames conforming to one of the formats shown in figure 1. Several
format types are shown in the figure:
- Format A is used on DCCHs for frames where there is no information field.
- Formats B, Bter and B4 are used on DCCHs for frames containing an information field:
- format Bter is used on request of higher layers if and only if short L2 header type 1 is supported and a UI
command is to be transmitted on SAPI 0;
- format B4 is used for UI frames transmitted by the network on SACCH;
- format B is applied in all other cases.
- Format Bbis is used only on BCCH, PCH, NCH, and AGCH.
- In addition there is a Format C for transmission of random access signals.
Format C frames are described in annex A. Format A, B, Bbis, Bter and B4 frames are described in the remainder of the
present document.
Bit 8 7 6 5 4 3 2 1
Octet No
: Address field :
k
Control field k+1
k+2
: Length indicator field :
n
n+1
: Fill bits :
N201+n
Format type A
Figure 1 (sheet 1 of 3): General frame formats
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8 7 6 5 4 3 2 1
Bit
Octet No
: Address field :
k
Control field k+1
k+2
: Length indicator field :
n
n+1
: Information field :
N
N+1
: Fill bits :
N201+n
Format type B
Bit 8 7 6 5 4 3 2 1
Octet No
:    :
: Information field :
: :
N201
Format type Bbis
Figure 1 (sheet 2 of
...